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Foot Design for a Large Walking Delta Robot | Biologically inspired approaches to robotics: what can we learn from insects? | Metric Factorization: Recommendation beyond Matrix Factorization | eng_Latn | 21,500 |
Multiple chaotic central pattern generators with learning for legged locomotion and malfunction compensation | Multiple chaotic central pattern generators for locomotion generation and leg damage compensation in a hexapod robot | Anatomic considerations and the relationship between the piriformis muscle and the sciatic nerve | eng_Latn | 21,501 |
Towards a Self-Organized Agent-Based Simulation Model for Exploration of Human Synaptic Connections | Tutorial on Agent-Based Modeling and Simulation PART 2: How to Model with Agents | Proprioceptive control of an over-actuated hexapod robot in unstructured terrain | eng_Latn | 21,502 |
Understanding Convolutional Neural Networks | Invariant Scattering Convolution Networks | Balance control of a unicycle robot | eng_Latn | 21,503 |
A Bio-Inspired Control Strategy for Locomotion of a Quadruped Robot | Learning, planning, and control for quadruped locomotion over challenging terrain | Citadel: Efficiently Protecting Stacked Memory from Large Granularity Failures | eng_Latn | 21,504 |
Learning in the Fast Lane: New Insights into Neuroplasticity | Structural basis of long-term potentiation in single dendritic spines | Spontaneous cross-species imitation in interactions between chimpanzees and zoo visitors | eng_Latn | 21,505 |
Teaching by demonstration on dual-arm robot using variable stiffness transferring | The central nervous system stabilizes unstable dynamics by learning optimal impedance | Unsupervised feature learning usingself-organizing maps. | eng_Latn | 21,506 |
Gecko adhesion: evolutionary nanotechnology | Whole body adhesion: hierarchical, directional and distributed control of adhesive forces for a climbing robot | genetics of antisocial personality disorder : literature review . | eng_Latn | 21,507 |
AQUA: An Amphibious Autonomous Robot | RHex: A Biologically Inspired Hexapod Runner | Multi-Domain Neural Machine Translation through Unsupervised Adaptation | eng_Latn | 21,508 |
Gecko inspired micro-fibrillar adhesives for wall climbing robots on micro/nanoscale rough surfaces | Gecko Inspired Surface Climbing Robots | An optimization model for collaborative recommendation using a covariance-based regularizer | eng_Latn | 21,509 |
Social acceptance of humanoid robots in Japan: A survey for development of the frankenstein syndorome questionnaire | Mechatronic design of NAO humanoid | embodied cognition : a field guide . | eng_Latn | 21,510 |
attitude vicon ( 100 hz ) step controller ( 100 hz ) laptop computer desktop computer robot thrusters tail leg motor driver . | Variable-speed quadrupedal bounding using impulse planning: Untethered high-speed 3D Running of MIT Cheetah 2 | Location and Clonal Analysis of Stem Cells and Their Differentiated Progeny in the Human Ocular Surface | eng_Latn | 21,511 |
Arbitrarily shaped formations of mobile robots: artificial potential fields and coordinate transformation | Materials for enabling hands-on robotics and stem education | B-cell depletion with rituximab in relapsing-remitting multiple sclerosis | eng_Latn | 21,512 |
Closed-Loop Neuromorphic Benchmarks | The Transferability Approach: Crossing the Reality Gap in Evolutionary Robotics | FingARtips: gesture based direct manipulation in Augmented Reality | eng_Latn | 21,513 |
Full-Body Compliant Human–Humanoid Interaction: Balancing in the Presence of Unknown External Forces | CB: a humanoid research platform for exploring neuroscience | Is it Happy?: Behavioural and Narrative Frame Complexity Impact Perceptions of a Simple Furry Robot's Emotions | eng_Latn | 21,514 |
Experimental Verification of the Oscillating Paddling Gait for an ePaddle-EGM Amphibious Locomotion Mechanism | snake - like robots [ tutorial ] . | Introducing a New Benchmarked Dataset for Activity Monitoring | eng_Latn | 21,515 |
Six-stator spherical induction motor for balancing mobile robots | The ballbot: An omnidirectional balancing mobile robot | modeling age progression in young faces . | eng_Latn | 21,516 |
A native Android application development based on watercolor stylized image | Towards Photo Watercolorization with Artistic Verisimilitude | Switchable Adhesion Actuator for Amphibious Climbing Soft Robot | eng_Latn | 21,517 |
Should Robots be Obedient? | Reinforcement Learning: A Survey | Distinct phospho-forms of cortactin differentially regulate actin polymerization and focal adhesions | deu_Latn | 21,518 |
A multiparadigm intelligent tutoring system for robotic arm training | Path integration and the neural basis of the 'cognitive map' | Microtubules in health and degenerative disease of the nervous system | eng_Latn | 21,519 |
A distributed approach to load balance for multi-robot task allocation | Analysis of Dynamic Task Allocation in Multi-Robot Systems | Encapsulation of Iron in Liposomes Significantly Improved the Efficiency of Iron Supplementation in Strenuously Exercised Rats | eng_Latn | 21,520 |
Long-Legged Hexapod Giacometti Robot Using Thin Soft McKibben Actuator | Soft-amphibious robot using thin and soft McKibben actuator | CAPIR: Collaborative Action Planning with Intention Recognition | kor_Hang | 21,521 |
Quality Diversity: A New Frontier for Evolutionary Computation | Evolutionary Robotics: What, Why, and Where to | Exercise-induced muscle damage in humans. | kor_Hang | 21,522 |
CB: a humanoid research platform for exploring neuroscience | Development of a new humanoid robot WABIAN-2 | The analysis, roles and regulation of quiescence in hematopoietic stem cells. | eng_Latn | 21,523 |
Design, fabrication and analysis of a body-caudal fin propulsion system for a microrobotic fish | Caterpillar locomotion: A new model for softbodied climbing and burrowing robots | Amphibot I: an amphibious snake-like robot | eng_Latn | 21,524 |
Hexapod robot: Test platform for bio-inspired controllers | A comparison of three insect-inspired locomotion controllers | Non invasive estimation of blood glucose using near infra red spectroscopy and double regression analysis | eng_Latn | 21,525 |
Neuromechanical models for insect locomotion: Stability, maneuverability, and proprioceptive feedback | A hexapedal jointed-leg model for insect locomotion in the horizontal plane | Sleep Deprivation and Vigilant Attention | eng_Latn | 21,526 |
Getting Humanoids to Move and Imitate | Learning by imitation: a hierarchical approach. | Compliance and Force Control for Computer Controlled Manipulators | eng_Latn | 21,527 |
Self-generated mobility via locomotion is a key for the cognitive, social and motor development of young infants. For certain children with special needs, self-generated mobility is only attained via assistive technology such as a power wheelchair. Up until recently, infants under 24 months of age were not considered candidates for training in power mobility. Recent work in our labs and others suggest that younger infants can utilize their reaching and grasping ability to learn power mobility. This interdisciplinary study combines our previous work in motor development and learning in infants with special needs, and the application of robot technology for rehabilitation to determine whether young infants without structured training, would drive a mobile robot, and if so, to determine how their driving would change over multiple sessions. The two infants that were seen for the most sessions were the focus of this pilot study. Both infants increased their total session time, percentage of session time spent driving, and total path length. These results suggest that, without training, young infants will independently move themselves using a mobile robot. These results provide the foundation for training studies to advance the self-generated mobility in young infants with special needs. Our future studies will explore the multiple training and technology combinations to reduce the barriers to exploration via self-generated mobility, and advance the general development of infants with special needs.. Title: Babies driving robots: self-generated mobility in very young infants | The goal of this research is to train children seated on mobile robots to purposefully and safely drive indoors. Our previous studies show that in about six weeks of training, infants can learn to drive directly to a goal using conventional joysticks. However, they are unable to acquire the advanced skill to avoid obstacles while driving. This limits mobility impaired children from exploring their home environment safely, which in turn impacts their cognitive and social developments in the important early years. In this paper, we describe results where toddlers are trained to drive a robot within an obstacle course. Using algorithms based on artificial potential fields to avoid obstacles, we create force field on the joystick that trains them to navigate while avoiding obstacles. In this ‘assist-as-needed’ approach, if the child steers the mobile robot outside a force tunnel centered around the desired direction, the driver experiences a bias force on the hand. The results suggest that force-feedback joystick results in faster learning than with a conventional joystick.. Title: Training toddlers seated on mobile robots to drive indoors amidst obstacles | This study reports the effects of powered mobility on the self-initiated behavior of six children with various disabilities who, between 23 and 38 months of age, learnt to use motorized wheelchairs in less than three weeks. Using a multiple baseline design, two-hour observation periods were video-recorded at 10-day intervals before and after they achieved independent mobility. Frequency of self-initiated interaction with objects, spatial exploration and communication with care-giver were analyzed. Three children increased all three types of behavior; one increased in two types but decreased in interaction with objects; and two increased in spatial exploration only.. Title: Localized diacylglycerol drives the polarization of the microtubule-organizing center in T cells | eng_Latn | 21,528 |
BEADS: High dimensional data cluster visualization | chameleon : hierarchical clustering using dynamic modeling . | soft robotics : from torque feedback controlled lightweightrobots to intrinsically compliant systems . | eng_Latn | 21,529 |
This was the concept that one could build an artificial object which was a stronger stimulus or releaser for an instinct than the object for which the instinct originally evolved . | This was the concept that an artificial object could be a stronger trigger for an instinct than the natural object for which the instinct originally evolved . | Lifelike or anatomically correct dolls are used by health professionals , medical schools , and social workers to train doctors and nurses in different health procedures or to find out about cases of sexual abuse of children . | eng_Latn | 21,530 |
Automatic Chatbot Knowledge Acquisition from Online Forum via Rough Set and Ensemble Learning | Rough Sets | An Underwater Surface-Drying Peptide Inspired by a Mussel Adhesive Protein | eng_Latn | 21,531 |
Securing the exocortex: A twenty-first century cybernetics challenge | Neurosecurity: security and privacy for neural devices. | How infants perceive the toy robot Pleo. An exploratory case study on infant-robot-interaction | eng_Latn | 21,532 |
Functional Hashing for Compressing Neural Networks | deep compression : compressing deep neural network with pruning , trained quantization and huffman coding . | A Biomimetic Underwater Soft Robot Inspired by Cephalopod Mollusc | eng_Latn | 21,533 |
Fitness and Novelty in Evolutionary Art | Enhancements to constrained novelty search: two-population novelty search for generating game content | velvet fingers : a dexterous gripper with active surfaces . | eng_Latn | 21,534 |
Robots could reduce animal tests | US scientists investigate whether robots could be used instead of animals for testing chemicals. | Computers can beat some of the world's top chess players, but the most powerful machines have failed at the popular Asian board game "Go" in which human intuition has so far proven key. | eng_Latn | 21,535 |
Continual Learning with Neural Networks: A Review | Variational Continual Learning | Sphenoderiidae (fam. nov.), a new clade of euglyphid testate amoebae characterized by small, round scales surrounding the aperture. | eng_Latn | 21,536 |
how does amoeba move | The term amoeba refers to simple eukaryotic organisms that move in a characteristic crawling fashion. However, a comparison of the genetic content of the various amoebae shows that these organisms are not necessarily closely related. | Many Protozoans have advanced evolved Cilia (hair like fibers) or Flagella(a big tail) which help them move. Where others, such as, the amoeba use a pseudopodia to move around by stretching its cytoplasm âpullingâ itself forward to its next destination. | eng_Latn | 21,537 |
How Nervous Systems Evolve in Relation to Their Embodiment: What We Can Learn from Octopuses and Other Molluscs | An octopus-bioinspired solution to movement and manipulation for soft robots. | The development of arithmetical abilities | eng_Latn | 21,538 |
How do Giant octopuses behave? | It depends how they've been brought up. Some octopuses teach their offspring to be polite, to say please and thankyou in all the right places, and even to give up their seat to a lady. \n\nSadly, these traditions are not much in evidence now. \nIn fact, I doubt if you will ever have been thanked by an octopus. \nMany of the young seem to do whatever they like, going out clubbing and suchlike at the weekend, drinking until they can't stand upright. \nIf you have doubts about that, just think. When was the last time you saw an octopus stand upright? \n\nOf course, this is just my opinion. If you want anything else, you could always try this site. It tells you more than anyone would ever want to know about octopuses. \n\nhttp://en.wikipedia.org/wiki/Octopus \n\nThough I'm not sure how accurate it is. It has a picture of a Big Blue Octopus that sure looks pink to me. \nAnd it doesn't mention rowdy behaviour either. \n\nHope that helps. | Do a simple web search. I got almost 1 million hits with most educational. There are entire book collections written on the subject. Narrow down your question with some research. | eng_Latn | 21,539 |
Evolving multi-objective strategies for task allocation of scientific workflows on public clouds | Taverna: A tool for the composition and enactment of bioinformatics workflows | Control of dynamic gaits for a quadrupedal robot | eng_Latn | 21,540 |
chapter 6 reconciling self - protection with self - improvement self - affirmation theory . | Self-regulation and depletion of limited resources: does self-control resemble a muscle | Optimization Algorithms Inspired by Biological Ants and Swarm Behavior | eng_Latn | 21,541 |
Can an Octopus bite you with it's beak? Can you really suck the poison out of a snake bite to keep from dying? | Of course it can. Most likely it will shy away from you, but it IS possible.\n\nAs far as sucking venom, it appears that treatment has fallen out of favor, but not because it harms the "sucker" but because it increases trauma in the wound area.\n\nInterestingly, from the FDA site below, it says sucking has fallen out of favor, but the CDC site below says it's OK! It also says that venom can be ingested orally with no ill effects.\n\nCDC: Do suck and squeeze - as much venom as possible directly from the wound. Venom is protein and can be taken orally with no ill effects. | faster processers, larger harddrives, and more ram memory\n\nThey also came out with a "Physx chip" that will process physics type code. It is designed to give the computer more processing power. It is also designed to take the strain off of pushing physics type code to the processor and just send it to "Physix" and it will process the code. \n\nThe "Physx chip" will make games look really real. To some, games already look really real, but they lack a lot of the characteristics of what is offered in life. Like if you sawed some guys head off on a game that is being processed by the "Physx chip", then blood will squirt out the right way. Depending on the angle you cut the head off at, it will fall either frontwards or backwards in respect to the angle that you were at when you were cutting the head off.\n\nI don't know why I used a decapitation example. I was just thinking of something horrific and gory at the moment.\n\nAlso, Microsoft is going to write an operating system type software for robots, so developers won't have to write as much low level code. Microsoft claims that robots will be used in the majority of business settings. | eng_Latn | 21,542 |
Control over β-form hybrid shish-kebab crystals in polypropylene pipe via coupled effect of self-assembly β nucleating agent and rotation extrusion | Reinforcement for polypropylene via self-assembly of β-form nucleating agent: new insight on the perpendicular orientation of lamellae | Reinforcement for polypropylene via self-assembly of β-form nucleating agent: new insight on the perpendicular orientation of lamellae | eng_Latn | 21,543 |
Development of emission factors for polypropylene processing | Elimination of Odors Emitted from Hot-Melting of Recycle PS by Oxidative-Reductive Scrubbing | CYP3A5 genotype is not associated with a higher risk of acute rejection in tacrolimus-treated renal transplant recipients | eng_Latn | 21,544 |
The effect of processing method on dry sliding performance of polyimides at high load/high velocity conditions | Tailored Porosity for Polymer Infiltration in Stainless Steel Coatings | Absence of CCR8 does not impair the response to ovalbumin-induced allergic airway disease. | eng_Latn | 21,545 |
Evaluation of contactor performance for extraction with ionic liquids | Conceptual process design for aromatic/aliphatic separation with ionic liquids | Simulation and Experiment Research of Non-contact Micro-liquid Reagent Dispensing | eng_Latn | 21,546 |
Estimating Thermal Stability of Experimental Polymers by Empirical Thermogravimetric Analysis | Compatibility and thermal decomposition behavior of acrylic block copolymer modified epoxy resin | Polyimides: Thermally Stable Polymers | eng_Latn | 21,547 |
Jet measurement with the CASTOR calorimeter | Measurement of inclusive very forward jet cross sections in proton-lead collisions at $\sqrt{s_\mathrm{NN}}=$ 5.02 TeV | Completely water-processable and other chemically amplified resists from maleic anhydride copolymers | eng_Latn | 21,548 |
Nonionic Surfactants from Recycled Poly(ethylene terephthalate) as Corrosion Inhibitors of Steel in 1 M HCl | Synthesis and Kinetics of Corrosion Inhibition of Water-Soluble Terpolymer of Polyvinyl Alcohol Functionalized with Vinyl Sulfonate and p-Vinyl Benzene Sulfonate, in Molar HCl | Spatiotemporal Nonattainment Assessment of Surface Water Tetrachloroethylene in New Jersey | eng_Latn | 21,549 |
Water-solubilized, cap-stabilized, helical polyalanines: calibration standards for NMR and CD analyses. | Coarse-grained, foldable, physical model of the polypeptide chain. | One-Pot Synthesis of Waterborne Polymeric Dispersions Stabilized with Alkali-Soluble Resins | eng_Latn | 21,550 |
Use of solutions of radiation-synthesized telomers of tetrafluoroethylene to modify glass fiber | Development of technological foundations of production of glass/polymer composite materials using tetrafluoroethylene oligomers (Telomers) as binders | Development of technological foundations of production of glass/polymer composite materials using tetrafluoroethylene oligomers (Telomers) as binders | eng_Latn | 21,551 |
Basic Aspects of Polymer Degradation | Multiscale Analysis of the Polymeric Insulators Degradation in Simulated Arid Environment Conditions: Cross-Correlation Assessment | Combinatorial discovery of polymers resistant to bacterial attachment | eng_Latn | 21,552 |
Miscible binary blends of poly(ethylene oxide) and poly(ether sulphone). Part 1 : Crystallization kinetics, morphology and thermal behavior | Miscibility of Polymer Blends Comprising Poly (Ethylene Oxide) - Epoxidized Natural Rubber | Miscibility of Polymer Blends Comprising Poly (Ethylene Oxide) - Epoxidized Natural Rubber | eng_Latn | 21,553 |
Removal of Microcontaminants From Surfaces Using a Chemicalfree, Laser-Assisted Process | Sacrificial layer process with laser-driven release for batch assembly operations | Methodological constraints in the molecular biodiversity study of a thermomineral spring cyanobacterial mat: a case study | eng_Latn | 21,554 |
An Onboard ATM Switching Fabric Based on Ant Algorithm with Blocking Avoidance | Satellite ATM networks: a survey | Easy access to oxygenated block polymers via switchable catalysis | eng_Latn | 21,555 |
Study of melting processes in fatty acids and oils mixtures. A comparison of photopyroelectric (PPE) and differential scanning calorimetry (DSC). | A Comprehensive Evaluation of the Melting Points of Fatty Acids and Esters Determined by Differential Scanning Calorimetry | Completely water-processable and other chemically amplified resists from maleic anhydride copolymers | eng_Latn | 21,556 |
The cure characteristics and mechanical properties of gum and filled acrylic rubber (ACM), fluorocarbon rubber (FKM), and their blends of varying compositions were studied both under unaged and aged conditions. The rheometric study showed that optimum cure properties were obtained using a mixed curing system of blocked diamine, hexamethylenediamine carbamate (Diak #1), and ammonium benzoate. From varying the curing agents, the optimum levels of Diak #1 and ammonium benzoate were found to be 1.5 and 2.5 phr, respectively. The addition of different fillers and their loading influenced the cure properties, with increased torque and reduced scorch safety. The gum and filled 50:50 (w/w) ACM-FKM showed overall performance in strength properties. Postcuring improved the strength of all the systems, especially the systems with a higher proportion of FKM. None of the properties changed significantly during aging of the blends. FKM and the blends containing a higher proportion of FKM were affected least by aging. Swelling of the blends was reduced by the addition of fillers. Dynamic mechanical thermal analysis showed a single tan δ peak corresponding to a single phase transition for both cured and filled blends. The storage modulus of the blend increased from the gum blend to the filled blend, indicating the presence of polymer-filler interaction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1442–1452, 2003 | The obtaining and characterization of some environmental-friendly composites that are based on natural rubber and plasticized starch, as filler, are presented. These were obtained by peroxide cross-linking in the presence of a polyfunctional monomer used here as cross-linking co-agent, trimethylolpropane trimethacrylate. The influence of plasticized starch amount on the composites physical and mechanical characteristics, gel fraction and cross-link density, water uptake, structure and morphology before and after accelerated (thermal) degradation, and natural (for one year in temperate climate) ageing, was studied. Differences of two orders of magnitude between the degradation/aging methods were registered in the case of some mechanical characteristics, by increasing the plasticized starch amount. The cross-link density, water uptake and mass loss were also significant affected by the plasticized starch amount increasing and exposing for one year to natural ageing in temperate climate. Based on the results of Fourier Transform Infrared Spectroscopy (FTIR) and cross-link density measurements, reaction mechanisms attributed to degradation induced by accelerated and natural ageing were done. SEM micrographs have confirmed in addition that by incorporating a quantity of hydrophilic starch amount over 20 phr and by exposing the composites to natural ageing, and then degradability can be enhanced by comparing with thermal degradation. | The combination of verapamil or diltiazem with beta-blockers should be avoided because of potentially profound adverse effects on AV (atrioventricular) nodal conduction, heart rate, or cardiac contractility. This effect is unpredictable but may be enhanced due to CYP2D6 poor metabolizer status which could be a special vulnerability factor. | eng_Latn | 21,557 |
This study determined the hardness, solubility and curing depth of a new photo-activated composite polymerized with three different laboratory photo-curing units for the purpose of evaluating the post-curing properties ofthe material. A new photo-activated composite material for both direct and indirect applications (DiamondCrown) was polymerized with three photo-curing units equipped with the following light sources: (i) two halogen lamps (DiamondLite-VLTM. Halogen Light Curing Booth); (ii) two metal halide lamps (Hyper LII) and (iii) two xenon stroboscopic tubes (UniXS II). Knoop hardness, water solubility and curing depth were determined for groups of five specimens according to standardized testing methods. All data were compared using analysis of variance (ANOVA) and Scheffe's S intervals (P < 0.05). The Knoop hardness number (KHN) generated with the metal halide unit (63.3 ′ 2.4 KHN) was statistically (P < 0.05) greater than those produced by the other two curing units. Water solubility values for both the halogen unit (2.5 ′ 0.5 pg mm - 3 ) and the metal halide unit (2.5 ′ 0.5 μg mm - 3 ) were significantly (P < 0.05) lower than for the xenon unit (3.8 ′ 0.5 μg mm - 3 ). Of the three photo-curing units, the metal halide curing-unit consistently exhibited the greatest depth of cure. The composite material appears to be reliable, although its post-curing properties were found to be influenced by the type of curing unit. | The purpose of this study was to eval- uate the depth of cure and Knoop hardness of indirect composite materials polymerized with different labo- ratory curing units. Five composite materials designed for fixed restoration veneer (Artglass, Ceramage, Epricord, Prossimo, and Solidex) were filled into a cylindrical mold and then light-exposed by using the respective proprietary laboratory curing unit or two metal halide curing units (Hyper LII and Twinkle X). Depth of cure was determined by a scraping technique, as described in ISO 4049. Composites also underwent Knoop hardness testing after immersion in water. The results (n = 5) were analyzed with the Kruskal-Wallis test and Dunn's multiple comparison test. For three materials (Prossimo, Artglass, and Epricord), depth of cure after polymerization with the Twinkle X unit was greater than that after polymerization with the respective proprietary units. For the Ceramage and Artglass materials, the Twinkle X unit resulted in the highest Knoop hardness number (KHN), whereas, for the Prossimo material, the Hyper LII unit resulted in the highest KHN. The metal halide units were effec- tive in enhancing the post-polymerization properties of specific composite materials while reducing expo- sure time. (J Oral Sci 54, 121-125, 2012) | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 21,558 |
We examine the technology of degradable polyethylene film, focusing on definitions, mechanisms, and testing procedures. three tecnological areas will be reviewed: photodegradation, biodegradation, and oxidative or chemical degradation. In addition, we will look at the current technology and research at Consolidated Thermoplastics Co. | Six corn starch-LDPE film blends containing starch in the range 5-40 % by weight, oleic acid as a Lewis catalyst with concentration of either 5 % or 10 %, maleic anhydride as a coupling agent with concentration of either 2 % or 10 % and benzoyl peroxide as free radical initiator with concentration of either 0.1 % or 0.25 % were prepared. Fungal growth tests (ASTM G21) using Penicillium funiculosum were carried out on the samples made according to the above formulations. Tensile tests (ASTM D638) and SEM imaging were also carried out on the samples before and after incubation with Penicillium funiculosum for three weeks. The results of ASTM G21 test and SEM imaging showed that the increase in starch content from 5 % to 40 % in the formulations containing all three additive increases the biodegradability of the samples whereas increase in the concentration of oleic acid from 5 % to 10 % has an opposite effect. Formulations containing only 5 % starch with a fairly high concentrations of additives or 40 % starch with no additives supported none or very little growth after three weeks, which indicates the importance of the concentration of starch and the presence of additives on the biodegradability of starch-LDPE film blends. Tensile test results showed that increase in starch content in the range of 20-30 % leads to a decrease in the values of the tensile strength and increase in the values of the elongation-at-break whereas further increase up to 40 % has the opposite effect. Tests with blends containing 40 % starch and no additive or 5 % starch with a fairly high concentration of additives resulted in low yield stresses and high elongation-at-break values. Increase the concentration of oleic acid from 5 % to 10 % in the blends resulted in a decrease in both the yield stress and elongation-at-break values. polyethylene; starch; biodegradable; Penicillium funiculosum. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 21,559 |
To improve knowledge on the biodegradation of cotton seed coat fragments in bioscouring, in this study Fourier-transform infrared (FT-IR) microspectroscopy was performed to analyze the composition of cotton seed coat. Microscope observation showed that cotton seed coat has a five-layer structure: epidermal layer, outer pigment layer, colorless layer, palisade layer, and inner pigment layer. Analysis of the FT-IR spectra from each layer shows that cutin, wax, cellulose, and pectin are the main components of the epidermal layer, while pectin and hemicellulose are the main constituents of the palisade layer, as well as aromatic and polyphenol, which are commonly considered as lignins. The main component of the outer and inner pigment layers is lignin. The results suggest that cellulase, pectinase, xylanase, and lignin oxidase are suitable for degradation of cotton seed coat. In addition, cutinase might be very promising in improving the enzymatic degradation of cotton seed coat. | Cutinases (E.C. 3.1.1.74) belong to the α/β-hydrolase superfamily. They were initially discovered because they are secreted by fungi to hydrolyze the ester bonds of the plant polymer cutin. Since then, they have been shown to catalyze the hydrolysis of a variety of polymers, insoluble triacylglycerols, and low-molecular-weight soluble esters. Cutinases are also capable of catalyzing esterification and transesterification reactions. These relatively small, versatile, secreted catalysts have shown promise in a number of industrial applications. This review begins by describing the characteristics of cutinases, pointing out key differences among cutinases, esterases and lipases, and reviewing recent progress in engineering improved cutinases. It continues with a review of the methods used to produce cutinases, with the goal of obtaining sufficient quantities of material for use in industrial processes. Finally, the uses of cutinases in the textile industry are described. The studies presented here demonstrate that the cutinases are poised to become important industrial catalysts, replacing older technologies with more environmentally friendly processes. | This paper reports a fabrication process for the deposition of a polymer insulation layer on the sidewall of through silicon vias in wafer level packaging. The novolac resin based glue was used as precursor to prepare the insulation layer. The glue is a Newtonian fluid and has low viscosity (24 mPa*s @ 100 l/s) as well as low contact angle (25.9°) to silicon. The resultant polymer insulation layer has a shearing strength as high as 25.8 Kg/mm2. Furthermore, the polymer insulation layer exhibits good uniformity in thickness and roughness over the whole 8″ wafer. On the conformal coating of the polymer insulation layer, the Ti/Cu seed layer and Cu conductive layer were fabricated by PVD and electroplating. Therefore, all the results show that the polymer materials could be a reliable and economical solution for the TSV insulator in the view of wafer level packaging. | eng_Latn | 21,560 |
Polymer degradation is an example of fragmentation of macromolecules of distributed molecular weight (MW). We investigated polystyrene (PS) oxidative degradation kinetics by di-tert-butyl peroxide in solvent trichlorobenzene at 428 K. Peroxide was consumed by the PS decomposition reaction and also by an independent deactivation reaction involving the polymer. Gel permeation chromatography (GPC) showed that the initial PS molar molecular weight distribution (MWD) was exponential in MW. After the peroxide was depleted (in less than 15 min), GPC analysis of polymer samples showed that the final MWD was also exponential in MW for all experimental conditions. The initial peroxide concentration, 5–40 g/l, and initial polymer concentration, 12.5–50 g/l, affected the reaction rates and hence the final MWDs. A continuous-distribution model for polymer fragmentation (first-order in both peroxide concentration and polymer MWD) and simultaneous peroxide deactivation (first-order in polymer concentration) describes the temporal behavior of the MWD and its moments. To be consistent with the experimental data, the model incorporates random chain scission and rate coefficients that increase linearly with MW. Moment analysis provides the ratio of the rate parameters for the peroxide deactivation and polymer decomposition. | Time-resolved rheometry was employed to study thermal and thermo-oxidative degradation of poly(ethylene terephthalate) (PET). Degradation results in a vertical downward shift of the complex viscosity in air atmosphere. We conclude that reduction of moduli and viscosity is governed by oligomers emerging from chain scission and acting as plasticizer. Additionally, cross-linking leading to a yield stress is observed at long times. In nitrogen atmosphere, polycondensation increases the molar mass and viscosity and extends the shear thinning regime. With longer degradation times, thermal degradation prevails and leads to a vertical downward shift. The reaction kinetics of three PETs with different molar mass was analyzed by a time constant τ assuming first-order kinetics. The low molecular weight PET exhibits the largest time constant in air atmosphere, and hence the lowest degradation rate, while high molecular weight PET exhibits a small τ and rapid degradation. The enhancement rate in nitrogen is vice versa. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 21,561 |
It is well known that polypropylene undergoes simultaneous crosslinking and degradation under irradiation.However, there are speculations regarding the formation of branching under special conditions. It is also well knownthat the melt-strength property ofa polymer increases with molecular weight and with long-chain branching due to theincrease in the entanglement level. This study was a contribution to the understanding ofthe following points: the roleofmolecular weight, the role ofstructural modifications on nucleation properties; the structural changes onpolypropylene.The results showed that degradation was the major reaction in the initial step ofirradiation, however, the largelymodified molecules concentrated in the high molecular weight fraction. The results also confirm that the branchingformation is likely to occur. r 2002 Elsevier Science Ltd. All rights reserved.1. IntroductionThe fathers ofradiation chemistry ofpolymers(Chapiro, 1962; Charlesby, 1960; Dole, 1973) havestudied Polypropylene irradiations in air or inertmedium. It was shown that PP undergoes pronounceddegradation in air and have similar trends to incrosslinking anddegradation underinertmedium. Otherauthors (Black and Lyons, 1957; Schnabel and Dole,1963) have already showed the effect of low-doseirradiation in vacuum. It was showed that an expressivedegradation occurs even in vacuum and low dose at theinitial stages ofirradiation. Controlled rheology PP orvisbreaking PP was already introduced in the marketand produced in some case by irradiation. For example,Williams et al. (1998) (US Pat. No. 5,820,981, 1998)disclose a process for reducing the molecular weight of apropylene polymer by activating the first portion ofthepolymer by exposing to ionizing radiation, adding theirradiated polymer to the second portion ofunirradiatedpolymer, adding a stabilizing amount ofan antioxidantto the mixture, and visbreaking by shear mixing in anextruder.PP has been extensively studied, as already shown, forseveral years, and even industrially used to produce PPgrades ofcontrolled rheology, nevertheless the use ofirradiation ofPP under N2 to promote long-chainbranching in order to improve the elongational viscositywas never reported before the clever patents of (Scheveet al., 1990; DeNicola et al., 1995) to Himont nowMontell (US Patent 4,916,198; US patent 5,414,027).PP suffers from low melt strength, i.e., the melted PPdoes not exhibit an increase in resistance to stretchingduring elongation. It is well known that the melt-strength properties ofa polymer increase with molecularweight and with long-chain branching due to theincrease in the entanglement level (high melt strengthPP–HMSPP). In spite ofbeing the most fast-growingpolymeric commodity nowadays those new grades ofPPand its development have been barely studied and its | It is well-known that the melt-strength properties of a polymer increases with molecular weight and with long chain branching due to the increase in the entanglement level. This study is a contribution for the understanding of the following points: — the role of branching, crosslinking and degradation on melt strength properties; — the mechanism and the kinetics of PP irradiation with time of irradiation and the importance of double bond formation. The results showed that degradation was the major reaction in the initial step of irradiation no matter the atmosphere and or antioxidant. However, double bond formation increased the production of branching and crosslinking reactions. Double bond formation had no effect on the crystallization kinetics, on the other hand, long chain branching had a marked effect on the crystallization temperature. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 21,562 |
A new epoxy resin matrix with good adherence to T800 carbon fibers (T800 CFs) in filament winding was developed by addition of hardener and resin diluter. Interfacial behavior of the T800 CF/epoxy composites was analyzed according to the Naval Ordnance laboratory (NOL) ring test, short-beam-shear test and fracture surface observation. Meanwhile, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used in analysis of the interfacial behavior. The interfacial properties of the T800 CF/epoxy filament wound composites were improved by optimizing the matrices through increasing the toughness and reducing the viscosity, which is an important factor in influencing the wettability of T800 CFs. The Interlaminar shear strength (ILSS) of the unidirectional T800 CF/epoxy composites and the tensile strength of NOL-ring in this work reached to 123 and 2570 MPa, respectively. Also, the interfacial adhesion was much improved by the chemical reactions between the new matrix and the sizing on the T800 CFs. | Non-isothermal curing reactions of three different multifunctional epoxy resin systems were investigated by differential scanning calorimetry. The Kissinger equation was applied to calculate the apparent activation energy, and the Levenberg–Marquardt algorithm was used to fit the curing kinetic data. It was observed that the two-parameter model was in good match with the curing kinetics. In addition, dynamic mechanical thermal analysis was used to obtain the glass transition temperature (Tg). Furthermore, the thermal stabilities of the systems were studied by thermogravimetric (TG) analysis, the integral procedure decomposition temperature and temperature index Ts were used to characterize the thermal stability. Finally, the gelation time was measured by plate–knife method of a home-made device, and the relationship between gelation time and temperature was established, according to which the pultrusion process parameters were predicted. | MLL1 regulates circadian promoters by depositing H3K4 trimethyl marks, whose levels are also modulated by the NAD+-dependent deacetylase SIRT1. SIRT1 is now shown to promote circadian deacetylation of MLL1, thus affecting MLL1's methyltransferase activity. | eng_Latn | 21,563 |
Viscosity behavior of incompatible poly(vinyl chloride) (PVC)/polystyrene (PS) blends in various solvents | Miscibility studies of pvc/pmma blends in tetrahydrofuran by viscosity, density, refractive index and ultrasonic velocity method | A Universal Optimal Consumption Rate for an Insider | eng_Latn | 21,564 |
Effects of hemicellulose content on TEMPO-mediated selective oxidation, and the properties of films prepared from bleached chemical pulp | A precise study on the feasibility of enzyme treatments of a kraft pulp for viscose application | High-speed running performance is largely unaffected by hypoxic reductions in aerobic power | eng_Latn | 21,565 |
Measurement of Nonlinearity and Spectral Study of a Laser Dye | Review: Evolution of Plastics in Medicine | On the Fundamental Limits of Recovering Tree Sparse Vectors From Noisy Linear Measurements | eng_Latn | 21,566 |
Comparison of manufacturer-recommended exposure durations with those determined using biaxial flexure strength and scraped composite thickness among a variety of light-curing units. | Light-curing considerations for resin-based composite materials: a review. Part II. | Completely water-processable and other chemically amplified resists from maleic anhydride copolymers | eng_Latn | 21,567 |
Control of Batch Free Radical Polymerization Reactors | Heterogeneous polymer systems. III. Phase separation in styrene-acrylonitrile copolymers | The polymerization of sickle hemoglobin in solutions and cells | eng_Latn | 21,568 |
Backstepping control of the one-phase stefan problem | Backstepping control of the Stefan problem with flowing liquid | Facile one-step photopatterning of polystyrene films | eng_Latn | 21,569 |
The Resistance of Semitransparent Photocathodes | The Image Tube In Ultra-High-Speed Frame And Streak Photography | Easy access to oxygenated block polymers via switchable catalysis | eng_Latn | 21,570 |
A Micrometer Syringe Dilatometer: Application to the Measurement of the Excess Volumes of some Ethylbenzene Systems at 298.15 K | Role of alcohol in microemulsions. III. Volumes and heat capacities in the continuous phase water-n-butanol-toluene of reverse micelles | Calibration of Microscopic Traffic Simulation Models: Methods and Application | eng_Latn | 21,571 |
LDPE phase composition in LDPE/Cu composites using thermal analysis and FTIR spectroscopy | CARS-PLS regression and ATR-FTIR spectroscopy for eco-friendly and fast composition analyses of LDPE/HDPE blends | Microtubule capture by CENP-E silences BubR1-dependent mitotic checkpoint signaling | eng_Latn | 21,572 |
Lack of effect on the sodium efflux of the microinjection of d-Ins(1,4,5)P3 into ouabain-poisoned barnacle muscle-fibers | Influence of pentachlorophenol on light emission from single barnacle muscle fibers preloaded with aequorin. | The ubiquity of frequency effects in first language acquisition* | eng_Latn | 21,573 |
Evaluation of polybenzimidazole-based polymers for the removal of uranium, thorium and palladium from aqueous medium | Sorption of europium and actinides by means of octyl(phenyl)-N,N-diisobutyl carbamoylmethyl phosphine oxide (CMPO) loaded on silica | Ultra-strong long-chain polyamide elastomers with programmable supramolecular interactions and oriented crystalline microstructures | eng_Latn | 21,574 |
A simple method is presented to estimate the detonation pressure of mixed CHNO explosives at various loading densities. This method is based upon a simple correlation in which the detonation pressure is interrelated by estimated gaseous detonation products and combustion temperature. Heat of formation calculated by semi-empirical PM3 procedure is used to calculate the combustion temperature. Calculated detonation pressure for known mixtures of CHNO explosives give results in better agreement with measured values than complicated BKW-EOS computer code. | This paper describes formulation of plastic bonded explosives (PBXs) compositions based on 2,4,6- triamino-1,3,5-trinitrobenzene (TATB), Octahydro l,3,5,7-tetranitro- 1,3,5,7-tetrazocine (HMX) by varying their relative amounts with Viton A as polymeric binder by slurry coating technique. These PBXs compositions are studied for mechanical and detonic properties. It has been observed that sensitivity and explosive performance of PBXs based on mixture of HMX and TATB were varied over a wide considerable range by varying relative amounts of TATB and HMX. The detonation study revealed there was increased in velocity of detonation (VOD) and detonation pressure with increasing amount of HMX from 10-80 % by weight. The sensitivity test results exhibited that insensitivity to impact for PBXs compositions was found to decrease with increasing HMX amount. Friction sensitivity study showed that no reactions were observed upto 36 kg load for PBXs compositions namely HT6030, HT5040, HT4050, HT3060, HT2070 and HT1080. The compressive strength of these PBXs compositions was found within the range of 9-11 MPa. Defence Science Journal, 2013, 63(6), pp.622 -629 , DOI:http://dx.doi.org/10.14429/dsj.63.5764 | The process of Vertical handoff has become one of the major components of today's wireless environment due to the availability of the vast variety of signals. The decision for a handoff should be performed catering to the needs of the current transmission that is being carried out. Our paper describes a modified Ant Colony Optimization based handoff mechanism, that considers multiple criteria in its decision making process rather than a single parameter (pheromone intensity). In general, ACO considers the pheromone intensity and the evaporation rates as the parameters for selecting a route. In this paper, we describe a mechanism that determines the evaporation rates of each path connected to the source using various criteria, which in turn reflects on the pheromone levels present in the path and hence the probability of selecting that route. Experiments show that our process exhibits better convergence rates, hence better usability. | eng_Latn | 21,575 |
Parylene, a chemical vapor deposited polymer, is shown here to have limited stability when annealed and/or bias temperature stressed. Parylene N thin films were preannealed at 250, 300, and 350°C for 30 min and then bias temperature stressed at 150°C and 0.5 MV/cm for 0, 30, 60, and 90 min. An order of magnitude increase in leakage current was observed for films preannealed at 300°C compared to the 250°C films but a precipitous increase was observed for the 350°C samples, which lead to shorting. Further, an electron spin resonance signal was observed for films annealed at 350°C without bias. | The thermoplastic nature of Parylene C is leveraged to enable the formation of three-dimensional structures using a thermal forming (thermoforming) technique. Thermoforming involves the heating of Parylene films above its glass transition temperature while they are physically confined in the final desired conformation. Micro and macro scale three-dimensional structures composed of Parylene thin films were developed using the thermoforming process, and the resulting chemical and mechanical changes to the films were characterized. No large changes to the surface and bulk chemistries of the polymer were observed following the thermoforming process conducted in vacuum. Heat treated structures exhibited increased stiffness by a maximum of 37% depending on the treatment temperature, due to an increase in crystallinity of the Parylene polymer. This study revealed important property changes resulting from the process, namely (1) the development of high strains in thermoformed areas of small radii of curvature (30?90??m) and (2) ?1.5% bulk material shrinkage in thermoformed multilayered Parylene?Parylene and Parylene?metal?Parylene films. Thermoforming is a simple process whereby three-dimensional structures can be achieved from Parylene C-based thin film structures with tunable mechanical properties as a function of treatment temperature. | The viscoelastic behavior of annealed fabric specimens produced from wool and manmade fibers has been assessed by measuring the fabric bending stress relaxation characteristics. The study reveals that the presence of water provides an effective me dium for de-ageing of fabrics produced from both wool and manmade fibers. Optimum annealing conditions occur when these fabrics are heated below the glass transition temperature of each fiber type at the equilibrium moisture regain corresponding to 20°C, 65% RH (the time taken depending on the annealing temperature). Under these conditions, the fabric bending stress relaxation rate is reduced to its minimum value, thus resulting in maximum fabric recovery from bending or wrinkling. The application of horizontal and vertical shift factors produces a master stress relaxation curve of aged and annealed fabric specimens produced from both wool and manmade fibers. | eng_Latn | 21,576 |
Multiplex PCR with fluorescently labeled primers has been an essential method for the amplification of short tandem repeats used in human identify testing. Within the STR workflow of extraction, quantitation, amplification, separation, and detection, multiplex PCR is commonly identified as the bottleneck in the process. The time requirement of up to three hours to complete 28-30 cycles of multiplex PCR for STR genotyping is the greatest amount of time required for a single step within the process. The historical use of commercially available thermal cyclers and heat stable polymerases may have given the impression that large multiplex will always require long PCR cycling times to ensure that all of the varying sized targets (typically 100-400bp) can be amplified in a balanced manner throughout the multiplex. However, with the advent of improved polymerases and faster thermal cyclers the time required for the amplification of large STR multiplexes is no longer on the order of three hours, but as little as 14min. Faster amplification times can be performed while retaining the balance and integrity of large multiplex PCRs by implementation of alternate polymerases and thermal cyclers. With the reduction in PCR cycling times there has also been an impact on the development of integrated and microfluidics devices which employ the use of reduced or rapid thermal cycling protocols as part of their integration. Similarly, PCR inhibitor resistant polymerases can also reduce overall STR processing times for reference samples by eliminating the need for DNA extraction and purification that is additionally implemented within the development of integrated DNA typing devices. | ObjectivesWith the widespread use of DNA testing, police, death investigators, and attorneys need to be aware of the capabilities of this technology. This review provides an overview of scenarios w... | By using a superluminescent diode as the light source and a depolariser inside the fibre coil, a constant scale factor is achieved without using polarisation control elements. For long-term behaviour an RMS-bias drift of 10 degrees/h is obtained. | eng_Latn | 21,577 |
The curing mechanisms and kinetics of diglycidyl ether of bisphenol A with diethylenetriamine as the curing agent and different amounts of organic montmorillonite were examined with isothermal and dynamic scanning calorimetry. The modified Avrami equation was used to calculate the activation energy and reaction orders in the isothermal experiment. A single peak was observed in each dynamic scan. The curing mechanism and kinetics of the curing reaction were also analyzed by two kinds of methods—Kissinger and Flynn–Wall–Ozawa. The results obtained from those methods under dynamic measurement agreed with those obtained from the modified Avrami equation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 378–386, 2003 | To investigate the influence of combustion modifiers on the curing of glycidyl azide polymer spherical propellants (GAPSPs), the curing process of the GAPSPs was explored using an isothermal rheological measurement method. The parameters of cure kinetics were solved to further establish a kinetic model for the curing reaction of GAPSPs. The results showed that the curing process of GAPSPs under isothermal conditions conformed to the Kamal and LSK (Lu–Shim–Kim) models. The model data indicated significant agreement with the experimental data. The influence of four kinds of combustion performance modifiers on the curing process was explored and the results demonstrated that lead phthalate had a catalytic effect on the curing reaction of GAPSPs, whilst oxides of lead and copper, and copper adipate had no influence on the curing reaction. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 21,578 |
The acrylonitrile-butadiene-styrene (ABS) surface was etched by dipping it into chromic acid-sulfuric acid containing a trace amount of palladium. The surface roughness, activity, and valence bond were characterized by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The results showed that with the increase of Pd concentration in the etching solution the ABS surface roughness reduced. The ratio of O to C increases and forms a large amount of O=C-O functional groups by dipping into Pd contained etching solution, thus the amount of colloids palladium adsorption increases. The carboxyl group acts as the adsorption site for the Pd/Sn catalyst. | ABS is an engineering plastic that has butadiene part uniformly distributed over the acrylonitrile-styrene matrix. It possesses excellent toughness, good dimensional stability, easy processing ability, chemical resistance, and cheapness. However, it suffers from inherent shortcomings in terms of mechanical strength and vulnerability to environmental conditions. Furthermore, it is non-conducting and easily fretted. Plating on ABS can serve to enhance the strength and structural integrity as well as to improve durability and thermal resistance resulting in metallic properties on the ABS material. ABS is described as the most suitable candidate for plating because it is possible to deposit an adherent metal coating on it by only the use of chemical pretreatment process and without the use of any mechanical abrasion. This article aims to review the history of ABS plastics, properties of ABS, processes and mechanisms of plating, and studies of plating on ABS involving mainly eco-friendly methods of plating by discussing the literature published in recent years. The details of electroplating of ABS carried out in the authors’ laboratory are also presented. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 21,579 |
Thin organic coatings commonly are used for insulating microelectrodes and electronic packages designed for implant applications. The adherence of these coatings to the underlying substrates is a key parameter in their selection for various devices. Instron pull tests were performed on glow-discharge polymerized monomers, Parylene-N, medical-grade Silastic and various epoxies. The application of a thin coating of glow-discharge polymerized methane under a thicker Parylene-N coating improved the adhesion of the latter to the underlying substrate in isotonic sodium chloride solution and during accelerated testing conditions done by boiling. | We conducted a neurophysiological study of attempted speech production in a paralyzed human volunteer using chronic microelectrode recordings. The volunteer suffers from locked-in syndrome leaving him in a state of near-total paralysis, though he maintains good cognition and sensation. In this study, we investigated the feasibility of supervised classification techniques for prediction of intended phoneme production in the absence of any overt movements including speech. Such classification or decoding ability has the potential to greatly improve the quality-of-life of many people who are otherwise unable to speak by providing a direct communicative link to the general community. We examined the performance of three classifiers on a multi-class discrimination problem in which the items were 38 American English phonemes including monophthong and diphthong vowels and consonants. The three classifiers differed in performance, but averaged between 16-21% overall accuracy (chance-level is 1/38 or 2.6%). Further, the distribution of phonemes classified statistically above chance was non-uniform though 20 of 38 phonemes were classified with statistical significance for all three classifiers. These preliminary results suggest supervised classification techniques are capable of performing large scale multi-class discrimination for attempted speech production and may provide the basis for future communication prostheses. | organic synthesis for preparation of functionalized oxygenated compounds. Solidphase synthesis, in particular reactions using polymer supported nucleophiles, have been widely used in organic synthesis mainly because of the ease of separation of products. Thus, as new polymeric reagents, Amberlite IRA-400 supported azide, nitrite and nitrate are introduced as polymeric reagents for efficient and regioselective conversion of epoxides to azidohydrins, nitrohydrins and nitratohydrins in good yields under mild reaction conditions. The advantages of these reagents over some of those reported in the literature, are easy work-up procedure, regeneration of the reagent, clean and neutral reaction conditions. In addition, no catalyst is required for occurrence of the reactions. Bahman Tamami, Naser Iranpoor, and Ramin Rezaie | eng_Latn | 21,580 |
Low-molecular-weight poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) was prepared by the redistribution of regular PPO with 4,4′-isopropylidenediphenol (bisphenol A) with benzoyl peroxide as an initiator in toluene. The redistributed PPO was characterized by proton nuclear magnetic resonance, mass spectra, and Fourier transform infrared spectroscopy. The redistributed PPO oligomers with terminal phenolic hydroxyl groups and low molecular weights (weight-average molecular weight = 800–4000) were used in the modification of a diglycidyl ether of bisphenol A/4,4′-diaminodiphenylmethane network system. The curing behaviors were investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy. The effect of molecular weight and the amount of redistributed PPO oligomers incorporated into the network on the physical properties of the resulting systems were investigated. The thermal properties of the cured redistributed PPO/epoxy resins were studied by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetric analysis, and dielectric analysis. These cured redistributed PPO/epoxy resins exhibited lower dielectric constants, dissipation factors, coefficients of thermal expansion, and moisture absorptions than those of the control diglycidyl ether of bisphenol A based epoxy. The effects of the composition on the glass-transition temperature and thermal stability are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 | Poly (2, 6-dimethyl-1, 4-phenylene oxide) (PPO) has been extensively investigated as an outstanding engineering plastic. Functionalized PPO with low molecular weight has been widely studied to expand its applications, while there are relatively few reports on PPO-containing coatings. In this work, a terminal phenolic hydroxyl group PPO (RPPO) with low molecular weight was synthesized by redistribution of high molecular weight commercial PPO with bisphenol A via benzoyl peroxide as an initiator. The self-curing, thermosetting RPPO-organic titanium chelate resins were first developed via the reaction between phenolic hydroxyl groups in RPPO and isopropoxy groups of diisopropoxy titanium bis (acetylacetonate). Thin coatings with 10 μm thickness could be obtained by heat curing without any curing agents. Characterization using Fourier transform infrared spectroscopy and 13 C nuclear magnetic resonance showed evidence of the successful preparation of the self-curing, thermosetting resins. The curing behavior and thermal stability were assessed via differential scanning calorimetry and thermo-gravimetric analysis. The mechanical properties of the cured coating were discussed and the chemical resistance was tested using accelerated immersion tests. Benefited by the self-curing mechanism, issues of non-uniformity, bubbles, and low storage stability caused by curing agents were avoided. It was found that the thin coating possessed good thermal and mechanical properties. Owing to the rigid aromatic chain structure and strong Ti-O bond in the crosslinked structure, the glass transition temperature was improved and the thermal degradation temperature could reach up to 402 °C. No degradation was found after 72 h accelerated immersion tests in boiling water, boiling seawater and boiling butanone, which should be critical to the resin’s potential application for anticorrosive coating. | The oxidative polymorphism of debrisoquine (DBQ) has been determined in 89 patients with colo-rectal cancer and in 556 normal control subjects. Four patients and 34 controls, with a metabolic ratio >12.6, were classified as poor metabolisers of DBQ (n.s.). | eng_Latn | 21,581 |
The common plastic film mulching technology causes a series of environmental issues while it controls or increases soil temperature and maintain soil humidity to increase crop yields and improve produce. The new pattern of plastic mulch film, it's called “Environmental Degradable Mulch Film” (EDMF), which successfully achieves degradation of appearance from pieces to powders. Therefore the effect of polyethylene powder products of EDMF on physical property and chemical property of soil becomes new hotspot of discussion. This study made use of four kinds of molecular weight to simulate polyethylene powder products of EDMF as soil additive of potted soybean, tested total P, efficient P, organic matter, acid phosphatase of soil in soybean developmental periods. The results showed that the total P content of experimental groups which added polyethylene powder products of EDMF were lower than control group, and the max decrement was 25.5%; efficient P content, organic matter content and acid phosphatase activity had no significant differences between experimental groups and control group in soil, and there were relativity among all of them. Efficient P and acid phosphatase activity, efficient P and organic matter were significant positive correlation (R=0.9982 R=0.9985); organic matter and acid phosphatase were negative correlation (R=−0.9966). The polyethylene powder products of EDMF have no significant effects on efficient P, organic matter and acid phosphatase in soil, whereas there are a little effect on speed total P consumption. | In a previous paper, we demonstrated that the main mechanism of degradation of poly(butylene adipate-co-terephthalate) (PBAT) biodegradable mulch films when exposed to field conditions was crosslinking due to the photodegradation from solar radiation. The aim of this work was to determine the effect of crosslinking on the biodegradability of PBAT samples. PBAT films were subjected to UV photodegradation in laboratory simulated conditions to investigate the effects of crosslinking and other major changes in the structure and mechanical properties of the films. Crosslinking caused the films to become more brittle and produced a reduction of the tensile strength and percent elongation. Besides the crosslinking degradation mechanism, chain scission also occurred in the samples. After 45d of biodegradation test, the non-crosslinked PBAT sample reached 60% of mineralization. However, the percent mineralization was reduced when samples were crosslinked. The percent mineralization of samples with 10%, 30%, 50%, and 70% gel content was 36%, 43%, 21%, and 24%, respectively. Our results indicate that crosslinking is a key process underlying the degradation of the PBAT film and did affect the biodegradability of the films, since the samples with greater amount of gel content generally showed less percent mineralization in the biodegradation tests. | Background ::: Serum calcium (Ca) and inorganic phosphate (Pi) concentrations and calcium-phosphate product (CPP) levels are positively associated with worse outcomes in patients with chronic kidney disease, but there are few data for Pi or Ca and none for CPP in patients with chronic heart failure (CHF). | eng_Latn | 21,582 |
Based on the techniques of laser microdrilling and solvent reflow, this study reports on a straightforward approach for fabricating plastic microlens arrays (MLAs). First, we use the ArF excimer laser to drill microholes on a polymethylmethacrylate plate for defining the lens number, initial depth, and diameter. The propylene glycol monomethyl ether acetate solvent is then employed to regulate the surface profile that leads to a resulting negative (concave) MLA. The corresponding positive (convex), polydimethyl-siloxane MLA is obtained by the soft-replica-molding technique. Through varying the pattern size and period on the mask and the light intensity for laser drilling and regulating the solvent in the reflow process, we exhibit the feasibility of making MLAs with various sizes and shapes. By modifying the laser ablation step to drill two microholes with different diameters and depths at two levels, we fabricate a bifocal microlens. The obtained microlenses have excellent surface and optical properties: surface roughness down to several nanometers and focal lengths varying from hundreds to thousands of micrometers. This approach is flexible for constructing microlenses with various sizes and shapes and can fabricate MLAs with a high fill factor. | Elastomeric stamps and molds provide a great opportunity to eliminate some of the disadvantages of photolithograpy, which is currently the leading technology for fabricating small structures. In the case of "soft lithography" there is no need for complex laboratory facilities and high-energy radiation. Therefore, this process is simple, inexpensive, and accessible even to molecular chemists. The current state of development in this promising area of research is presented here. | MLL1 regulates circadian promoters by depositing H3K4 trimethyl marks, whose levels are also modulated by the NAD+-dependent deacetylase SIRT1. SIRT1 is now shown to promote circadian deacetylation of MLL1, thus affecting MLL1's methyltransferase activity. | eng_Latn | 21,583 |
'I'he dyeing properties of modified wools containing internally deposited acrylic polymers with Acid Blue 45, Basic Blue 1, Disperse Blue 1, Reactive Red 4, and Reactive Orange 29 have been investigated at 60°C over 90-min dyeing , periods. In most cases, the acrylic polymers deposited within the wool matrix increased both the rate of dye uptake and the percentage of dye exhausted onto the wool. Also, chemical fixation of the reactive dyes was markedly increased by the presence of polymer within the wool. The nature of the side chain on the acrylic polymer appeared to have little systematic effect on the dyeing properties of the fibers, with the exception of poly (acrylic acid) which tended to retard dye uptake where the internal pH within the fiber during dyeing was an important factor. | Seven basic dyes have been applied to wool yarn in 0.5% depth at 40, 60 and 80dC, as well as over a range of pH values at 60dC. As far as wool is concerned, basic dyes appear to be rapid-dyeing dyes of low affinity, the exhaustion of which is very sensitive to change in pH in the region pH 4–6. | A water soluble azo dye modified β-cyclodextrin polymer 4 was synthesized and used as a chemosensor for the detection of chlorinated phenols, model chlorinated by-products (CBPs) of water treatment for drinking purposes. The characterization of the intermediates and the azo dye modified β-CD polymer was done by UV/Vis Spectrophotometry, FT-IR and (1)H-NMR spectroscopies. The chlorophenols were capable of quenching the fluorescence of the polymer. The polymer showed greater sensitivity towards 2,4-dichlorophenol, with a sensitivity factor of 0.35 compared to 0.05 and 0.12 for phenol and 4-chlorophenol, respectively. The stability constants (K(s)) of the pollutants were also determined by the Benesi-Hildebrand method to be 2.104 × 10(3) M(-1) for 2,4-dichlorophenol and 1.120 × 10(2) M(-1) for 4-chlorophenol. | eng_Latn | 21,584 |
Ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic semicrystalline polymer that has outstanding mechanical properties, low friction coefficient, excellent wear resistance, and is highly resistant to corrosive chemicals. UHMWPE is found in many applications including artificial joints and filtration. However, UHMWPE parts cannot be produced easily by traditional techniques, such as injection moulding and extrusion because of its very high melt viscosity owing to the extremely long polymer chains. Few attempts were made to process UHMWPE by additive manufacturing, particularly laser sintering. This is due to the lack of understanding of the powder properties of UHMWPE. Therefore, the aim of the powder characterisation process in this study is to gain a better understanding of the material requirements and provide a detailed insight on whether UHMWPE is a suitable material for laser sintering. The characterisation process includes powder morphological and flow characteristics, thermal behaviour and stability, and crystallinity of UHMWPE. The study reveals that the sintering behaviour of polymers is controlled by the morphology of the particles in addition to the viscous flow of UHMWPE. There are still difficulties of processing UHMWPE due to highly agglomerated structure of smaller particles with the presence of fibrils in the UHMWPE particles. | This research highlights the fact that individual particles are melted to different degrees during Selective Laser Sintering ® (SLS) of Nylon 12. Many particles comprise an un-melted core, surrounded by a melted and crystallised mass that bonds with other particles. Methods to quantify the Degree of Particle Melt (DPM), including Differential Scanning Calorimetry (DSC) analysis and optical microscopy analysis, are compared against each other and against mechanical properties of parts manufactured under different conditions. The results show that the derived DPM has a close correlation with mechanical properties. This represents a new depth of understanding of the SLS process. | An investigation was reported on the effect of foaming parameters on the microstructure, mechanical properties, and thermal conductivity of low-density polyethylene (LDPE) foams containing various amount of ultrahigh-molecular-weight-polyethylene (UHMWPE) as a reducer of chemical cross-linking. Azodicarbonamide (ADCA) and dicumyl peroxide (DCP) were used as foaming agent and cross-linking agent, respectively. The LDPE/UHMWPE blends were prepared in an internal mixer and foamed using a single-stage compression molding technique. Considering various parameters and their levels, optimization of Taguchi experimental design was carried out, an L9 orthogonal standard array was selected and the efficient levels for different variables were calculated using analysis of variance (ANOVA) of the results. Also due to different objective functions investigated in this process, optimization of overall evaluation criteria (OEC) method was used. The results revealed that addition of UHMWPE leads to a significant increase... | eng_Latn | 21,585 |
For resolving the contradiction of the stability between styrene-butadiene-styrene (SBS)-modified bitumen emulsion and the concentration of SBS, a method of preparing SBS latex is provided in this article. Results showed that SBS latex had good stability properties and performance. The effect of emulsifier concentration on the storage stability showed that the maximum stability of SBS latex–modified bitumen emulsion (SBS-LMBE) was obtained at emulsifier weight concentration 1.0% and addition of SBS latex to bitumen emulsion enhanced the difficulty of emulsification. The effects of SBS latex on bitumen properties showed the penetration decreased, whereas the softening point and ductility at 5°C increased, which means that SBS latex plays a role in improving the properties of bitumen. Compared to the base bitumen, saturate and aromatic of evaporation residue of SBS-LMBE decreased. However, resin and asphaltene increased. Analysis of the relationship between the components and properties of bitumen ... | The aim of this research was to characterize and analyze the formulation of emulsified modification bitumen (EMB) as well as the industrial wastes used in the formulation. Bitumen being a non-renewable product with severe environmental issues arising lately led to the use of industrial wastes such as plastic and recycled base oil in this research. Physical characteristic studies were performed to analyze the decomposition temperature, boiling point, flash point, density, moisture content, element content in waste plastics, and flowability of bitumen emulsion. Eight ratios of modified bitumen were formulated and compared with the industrial grade bitumen. The modified bitumen with a penetration value of 103 mm and softening value at 49 °C was chosen for the emulsification process where three emulsifiers were added into the mixture of bitumen and water. These samples were compared with the industrial bitumen emulsion. From the analysis, the formulated emulsion was obtained from a mixture consists of 20% bitumen, 7% polymer, and 73% recycled base oil. | By using a superluminescent diode as the light source and a depolariser inside the fibre coil, a constant scale factor is achieved without using polarisation control elements. For long-term behaviour an RMS-bias drift of 10 degrees/h is obtained. | eng_Latn | 21,586 |
The feasibility of using the enzyme laccase to treat synthetic wastewater containing bisphenol-A (BPA) was examined. Optimization of pH, laccase concentration, polyethylene glycol (PEG) as an additive for >95% conversion and precipitation of BPA over 3 h of reaction period was determined through colorimetric assay and HPLC. PEG reduced enzyme inactivation, allowing a 5.2-fold reduction in the amount of laccase required for >95% removal of BPA in the range of 0.1-1 mM over 3 h. The fate of PEG after the reaction was also monitored. Linear relationships were found between the concentration of BPA (0.1-1 mM) and the optimum concentrations of laccase and PEG. Little PEG remained in the solution when up to 75 mg/L of PEG was used to treat 0.5 mM BPA. Beyond this level, PEG concentration increased linearly in the supernatant. It is inferred that an interaction between PEG and the polymeric products resulted in the protection of laccase. | Water quality monitoring in resource-limited settings without access to a sophisticated laboratory requires the development of low cost and portable instrumentation. Herein, we propose a newly designed handheld reflection-based smartphone sensing platform to detect Bisphenol-A (BPA), a well-known endocrine disruptor agent abundantly used in plastic industry. An experimental investigation relying on color change due to the formation of quinone-type complex was conducted with samples from two different water sources: distilled and commercial drinking water. This colorimetric measurement device was used to determine BPA in distilled water in alkaline environments. The successful combination of colorimetric assay and spectrometer facilitates limit of detection in the low ppm levels, 0.29 ppm for smartphone and 0.23 ppm for commercial spectrometer, with a sensitivity of 0.1/ppm. | Polyethylene glycol (PEG-400) was found to be an inexpensive, non-toxic, and effective medium for the one-pot synthesis of 1,2-disubstituted benzimidazoles in excellent yields. Eco-friendliness, low cost, high yields, and recyclability of the PEG-400 are the important features of this protocol. | eng_Latn | 21,587 |
An important tool for studying standard finitely presented algebras is the Ufnarovski graph. In this paper we extend the use of the Ufnarovski graph to automaton algebras, introducing the generalized Ufnarovski graph. As an application, we show how this construction can be used to test Noetherianity of automaton algebras. | A process of modifying the levelling characteristics of a film of a polar liquid coating composition by incorporating therein 0.5-60% by weight of an amphipathic random copolymer which comprises 5-50% of a monomer which has a chain-like structure at least 80 covalent bonds long and which is soluble in poly(ethylene oxide) of molecular weight 400, and 25-95% of a (meth)acrylate monomer which comprises a chain-like moiety of at least 10 covalent atoms long and which is not soluble in poly(ethylene oxide) of molecular weight 400. The resulting copolymer may be added to polar liquid coating compositions to give useful improvements in flow and levelling characteristics. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 21,588 |
On-line ultrasonic monitoring of polymer co-extrusion and gas-assisted injection molding are presented. During the co-extrusion of high density polyethylene (HDPE) and Santoprene ultrasonic sensors consisting of piezoelectric transducers and clad ultrasonic buffer rods are used to detect the interface between these two polymers and the stability of the extrusion. The same ultrasonic sensor also measures the surface temperature of the extruded polymer. The results indicate that temperature measurements using ultrasound have a faster response time than those obtained by conventional thermocouples. In gas-assisted injection molding the polymer and gas flow front positions are monitored simultaneously. This information may be used to control the plunger movement. | Preface. 1. The Complete Injection Molding Process. 2. Injection Molding Machine. 3. Plasticizing. 4. Molds to Products. 5. Fundamentals of Designing Products. 6. Molding Materials. 7. Process Control. 8. Design Features that Influence Product Performances. 9. Computer Operations. 10. Auxiliary Equipment and Secondary Operations. 11. Troubleshooting and Maintenance. 12. Testing, Inspection, and Quality Control. 13. Statistical Process Control and Quality Control. 14. Costing, Economics, Management. 15. Specialized Injection Molding Processes. 16. Injection Molding Competitive. 17. Summary. Appendices. References. | Introduction: Due to thermal hazard in composite restorations, this study was designed to scan the pulp temperature by thermocouple and infrared camera during photo polymerizing different composites. Methods and Materials: A mesio-occlso-distal (MOD) cavity was prepared in an extracted tooth and the K-type thermocouple was fixed in its pulp chamber. Subsequently, 1 mm increment of each composites were inserted (four composite types were incorporated) and photo polymerized employing either LED or QTH systems for 60 sec while the temperature was recorded with 10 sec intervals. Ultimately, the same tooth was hemisected bucco-lingually and the amalgam was removed. The same composite curing procedure was repeated while the thermogram was recorded using an infrared camera. Thereafter, the data was analyzed by repeated measured ANOVA followed by Tukey’s HSD Post Hoc test for multiple comparisons ( α =0.05). Results: The pulp temperature was significantly increased (repeated measures) during photo polymerization ( P =0.000) while there was no significant difference among the results recorded by thermocouple comparing to infrared camera ( P >0.05). Moreover, different composite materials and LCUs lead to similar outcomes ( P >0.05). Conclusion: Although various composites have significant different chemical compositions, they lead to similar pulp thermal changes. Moreover, both the infrared camera and the thermocouple would record parallel results of dental pulp temperature. Keywords: Exothermic Reaction; Infrared Camera; Light Curing Unit; Pulp Temperature; Resin Composite; Thermocouple | eng_Latn | 21,589 |
A series of novel bismaleimides (BMIs) were prepared from maleic anhydride and polyurethane prepolymers based on MDI (4,4′-diphenylmethane diisocyanate) and polyether and polyester diols with various chain lengths. All the BMIs were characterized by IR, 1H-NMR, and elemental analysis. DSC studies indicated that the thermal polymerization of the BMIs could be carried out in the temperature range of 102–245°C, and that curing behavior was significantly affected by the molecular weight of the BMIs. The crosslinked BMI elastomers showed good mechanical properties and much better thermal stability than that of the traditional polyurethane elastomers. The glass transition temperatures, mechanical, and dynamic mechanical properties were dependent on the types of polyols used and the resultant crosslink densities due to various chain lengths of the BMIs. © 1994 John Wiley & Sons, Inc. | Two novel diols having both imide and aromatic groups in main chains, including N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol (PBDCG) and N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester butynediol (PBDCB), were synthesized. Then, the novel thermoplastic-segmented poly(urethane–imide)s (PUIs), in which 4,4′-diphenylmethane diisocyanate and the diols as the hard segments and poly(tetrahydrofuran) as the soft segments, were prepared via two-step polymerization. The prepared polymers were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography, tensile tests and UL 94 vertical burn test. TGA result indicates that the novel PUIs with the rigid hard segments have slower degradation rates than the conventional polyurethanes, and PBDCB-based PUIs are more thermally stable than PBDCG-based PUIs. DSC and x-ray diffraction results confirm that they are amorphous structures. Moreover, DSC a... | 2-Methylisoborneol (MIB) and geosmin (GSM) are taste and odor compounds produced by cyanobacteria in surface waters. While the strong odors and musty flavors of MIB and GSM are generally associated with poor water quality, the removal of these semi-volatile compounds presents a significant challenge to drinking water providers. Likewise in aquaculture, accumulation of these compounds in fish meat leads to quality problems and reduces marketability. Conventional water treatments are ineffective at removing low concentration of odor compounds. We report herein ultrasonic irradiation at 640 kHz leads to rapid degradation of MIB and GSM. While radical processes generally dominate during ultrasonic-induced degradation, pyrolysis appears to be responsible for a significant fraction of the observed degradation. Several pyrolytic products from MIB and GSM have been identified and degradation pathways are elucidated. The degradation of MIB and GSM follows the first-order kinetics and the rate constants are 0.07 and 0.12 min −1 , respectively. These results suggest ultrasonic irradiation maybe applicable as an effective method for removal of taint compounds from potable water supplies and fish farms. | eng_Latn | 21,590 |
Introduction: Aluminum (Al) is a standard material that has been used as a filter for ionising radiation however for polyvinyl chloride (PVC) there is no solid evidence to support but has been recommended. PVC has been selected as a potential filter material due to it is a long lasting constructing material and very durable, which can be used in a variety of application. The purpose of this study was to observe the effect of PVC on entrance surface dose (ESD) values as compare to the standard X-ray filter of Al. ::: Method: The effect of varying thickness of the materials and difference exposure settings were observed and compared to each other. ::: Result: From this study, the percentage difference for both PVC and Al thickness is less than ± 25.00%. ::: Conclusion: The finding suggests that PVC has a potential to be used as one of the filter materials due to its ability to reduce the ESD value. | The energy subtraction (ES) method is a technique that eliminate an image of an arbitrary organ by subtracting two images acquired by x rays with different energy owing to the property that an absorption coefficient of each organ has peculiar energy dependence. Namely, the ES method allows us to identify each organ. However, the organs that have the same absorption coefficient are sometimes presented as different ones. The use of monochromatic x rays may further improve the power to discriminate organs having the similar absorption coefficients from each other. In clinical situations, however, it is very difficult to produce monochromatic x rays. Therefore, the purpose of this study is to evaluate ES images by using x rays with a sharpened energy spectrum by metal filters. The x rays were generated from a tube in clinical use. The energy band of the white x rays were sharpened both for high and low energy regions by combination of metal filters. The spectra of filtered x rays were well sharpened compared with those of x rays with no filter. The original images were acquired by the dual-energy white x rays and dual-energy sharpened x rays for a phantom which was composed of several bone phantoms and several syringes containing NaClaq with different concentration. These images were obtained by the use of a flat panel detector, and ES images were processed. In the ES image for the sharpened energy spectrum, the contrast of NaClaq overlapped by a tough bone phantom was increased three to five times larger compared with that for the broadband energy spectrum. These experimental results indicate that the use of the sharpened energy spectrum increases the contrast of the ES images largely even for organs having a similar absorption coefficient. | Accumulation of enormous amounts of plastic waste produced all over the world has negative implications on the environment. Pyrolysis of plastic waste could have an important role in converting this waste into economically valuable hydrocarbons, which can be used either as fuels or as feed stock in the petrochemical industry. End product yields and properties depend on the plastic waste composition. The presence of PE (polyethylene) increased alkane content, whilst PS (polystyrene) led to higher aromatic content in the end product. The presence of PP (polypropylene) favoured alkene formation. Therefore, both PS and PP increased the octane number of end product. Therefore, the desired end product can be obtained by adequate blending of plastic wastes. | eng_Latn | 21,591 |
For the first time, comprehensive two-dimensional liquid chromatography (2D-LC) of complex polymers is coupled online to 1H NMR. 2D-LC is used to separate mixtures of poly(ethylene oxide)s with regard to chemical composition and molar mass. The present samples contain polymers with different end groups and chain distributions. In the first LC dimension, liquid chromatography at critical conditions (LCCC) is used for the selective separation according to the end groups. Fractions that are then uniform regarding their end groups are automatically transferred into the second LC dimension which separates the fractions regarding their chain length distributions using liquid adsorption chromatography. The eluate from 2D-LC is directly introduced into the 1H NMR for on-flow analysis. The online coupling of one- and two-dimensional chromatography with 1H NMR detection is demonstrated. The NMR is coupled to both individual separations as well as to the entire two-dimensional separation. As a result of this multidi... | We find polymers everywhere in our daily activities, for example, as a part of consumer electronics products, healthcare devices, vehicles, etc. Analytical characterization of such materials is an important step towards understanding their properties and behavior in various applications. The increase of material complexity driven by highly demanding requirements for many applications necessitates the use of sophisticated analytical techniques to obtain sufficient insight into the structure of these materials. Coupling of liquid chromatography with other information-rich instrumental techniques becomes more and more important in the field of polymer characterization. Such combination can enable simultaneous separation, identification, and quantification of polymer sample components. In addition, it can provide information on interdependence of two polymer properties, e.g., molecular weight and chemical composition. Different hyphenated systems may be applied to address different problems in polymer research and development and a selection of the right technique may not be an easy and straightforward task. In this paper, the applications of LC-NMR, LC-IR, LC-Raman, LC-MS, LC-MALDI, LC × LC, and LC × Py-GC for polymer analysis are reviewed, their advantages and limitations are discussed, and practical challenges for the implementation of these techniques in a lab are addressed. Different hyphenated options are compared to facilitate selection of a suitable instrument for the particular problem at hand. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 21,592 |
Red rubber sleeve stoppers used as substrates for the sex pheromone of the codling moth, Laspeyresia pomonella (L.), produced a 1st order loss curve (k = 1.09 × 10−3/h corresponding to a half-life of 26.5 days); rubber bands produced a complex loss curve; and polyethylene caps allowed extensive chemical degradation after a few days. In field trapping tests, a release rate of 1.25 μg/h produced the highest catches. Sleeve stoppers baited with 1.5 mg of attractant/stopper had virtually maximum attractiveness for a month and would be ideal for mass trapping during this period. Sleeve stoppers baited with 5 mg of attractant/stopper may be used for survey since the rate loss curve indicates they will be more attractive than the old survey bait of 10 ♀ after as much as 4.4 mo (5 half-lives). | Performance characteristics of polyethylene tube dispensers containing a mixture of (E,E)-8,10-dodecadien-1-ol (1), dodecan-1-ol (2), and tetradecan-1-ol (3) were evaluated for suitability as a mating disruptant for codling moth control. The rate of loss of pheromone component from a dispenser at any time was found to be described by the equation: −dP/dt=(k1k2 +kd)P whereP is the amount of pheromone component in the dispenser well;t is time;k 1 is the ratio of the amount dissolved in the dispenser wall to the amount in the dispenser well;k 1 is the ratio of the evaporation rate to the amount dissolved in the dispenser wall;k d is the rate constant for chemical decomposition. The evaporation rate,E, of a pheromone component at any time was given by:E=k 1 k 2 P For all three components during the first three weeks,k 1 decreased from ca. 0.25 to ca. 0.10 and was approximately constant thereafter. The decrease ofk 1 with time may have been caused by weather-induced cross-linking of the polyethylene. Over timek 2 was constant and was 1.27 ± 0.26 × 10−3/hr for1, 1.96 ± 0.33 × 10su−3/hr for 2, and 0.31± 0.05 × 10−3/hr for 3. Thek 2 was zero for2 and3 and 6.96 × 10−4 for1. After 150 days in an orchard in 1991, 95% of1 was lost from the dispensers (61% of the loss was by chemical decomposition and 39% by evaporation). The heat summation units in a Yakima valley orchard during 1991 were 4.7% above the average for the 1980–1991 period, while during 1990 they were the highest for this period (26% above average). After the first three weeks of dispenser aging, the regression line half-lives for1 for 1990 and 1991 were 31.0 and 35.1 days, respectively. The difference in temperature between 1990 and 1991 did not affect the half-life of1 very much because so much of the loss was from photochemically induced decomposition. Based on an estimate of the required minimum evaporation rate for mating disruption of 2 mg/ha-hr and a half-life of 35 days for1, 2345 dispensers/ha would be required for one application per season; 944 dispensers/ha for two applications per season; and 734 dispensers/ha for three applications per season. If a different emission rate of1 is required for reliable mating disruption, then the number of dispensers required would be changed proportionately. | A universal building block for modular design of microwave filters is introduced. The second order block contains two resonators which are not coupled to each other. By adjusting the strengths and signs of its coupling coefficients, the block can be used to design bandpass, bandstop and linear-phase filters. For bandpass filters, Chebychev as well as symmetric and asymmetric pseudo-elliptic responses with one or two finite transmission zeros can be designed. For linear-phase filters, two finite transmission zeros can placed practically anywhere in the complex plane as long as the realizability condition is met. Bandstop filters with no finite reflection zeros as well as symmetric and asymmetric pseudo-elliptic responses with one or two finite reflection zeros can be achieved by the same building block. The block is so flexible it can even generate bandstop responses with complex finite reflection zeros for group delay control. Higher order filters are designed modularly by cascading the appropriate number of building blocks. Coupling matrices of a number of cases are presented to demonstrate the flexibility and the universality of the building block. | eng_Latn | 21,593 |
Wood is commonly used as a construction material for floors, outdoor decks, house framing, bridges etc. However, the dimensional instability of wood has limited its use in these and other applications. This is due in part to the constant adsorption and release of water which results in swelling and shrinking leading to the physical degradation of the wood (Kumar 1994). A variety of treatment methods has been developed in an attempt to improve the hardness, stability, stiffness, and dimensional stability of wood. However, many of these methods are not economic or commercially scalable. There still exists a need for a commercially viable wood treating technology which will provide increased dimensional stability and hardness. This article details a wood treating method using a difunctional epoxide cured with a catalyst at low temperature inside of the wood to prepare a wood polymer composite (WPOC). Analysis by scanning electron microscopy (SEM) and micro infrared spectroscopy (micro IR) showed the epoxy resin was distributed uniformly throughout the wood including the cell wall. The epoxide treated wood compared to untreated wood showed improvements in hydrophobicity (water repellency), anti-swelling efficiency (ASE) as a measure of dimensional stability, hardness, and three-point bending dynamic mechanical analysis (DMA) properties. | This paper is an update of several earlier review articles on wood polymer composites (WPC). Notable polymer types that have been used to make WPC are phenol-formaldehyde (PF), various vinyls, and furfuryl alcohol. Phenol-formaldehyde and similar chemicals typically enter wood cell walls, whereas the vinyls usually fill cell lumens. Combination treatments that modify both lumens and walls are possible. Diffusion and mass flow are two possible methods of introducing the chemical into the wood. Curing can be accomplished using a catalyst and heat or penetrating radiation. Type of treating chemical and final density are major determinants of WPC properties. Physical and mechanical properties of WPC have been extensively studied. Major WPC improvements over untreated wood are in hardness, finishability, and dimensional stability. There is much yet to be learned about chemical formulations, treating and curing, and their relationships to property enhancements, WPC recyclability, and chemicals from renewable sources for making WPC. | SUMMARY Cookies were prepared with the replacement of 20% of wheat flour by chemically (alkaline hydrogen peroxide) and physically (extrusion) treated oat hulls, with the objective to investigate the possibility of use of this modified material. Cookies elaborated with the untreated hulls were used as control. Cookies were evaluated for their physical (spread ratio, specific volume and color) and sensory characteristics, and no difference was detected (p≤0.05) among the cookies in relation to the physical properties. Triangule test, used to verify difference (p≤0.05) among treated and untreated cookies, confirmed the efficiency of the treatment in sensory level. The acceptance level of cookies with treated fiber was evaluated by potential consumers of the product, obtaining 91% acceptance. The cookies presented 10.6 g of dietary fiber per 100 g of product. | eng_Latn | 21,594 |
The decomposition of the peroxide group on fibrous carboxymethyl cellulose (CMC) and its ability to initiate graft copolymerization were investigated. The peroxide on CMC liberated hydrogen peroxide when the sample was heated in an aqueous medium. The decomposition of the peroxide was markedly increased by the use of ferrous salt and the irradiation with light of λ > 300 nm. The grafting of methyl methacrylate on CMC peroxide was initiated by heating or irradiating with light, where the rate of grafting and the reciprocal of the average molecular weight of grafts in general were proportional to the square root of the peroxide content of the sample. The peroxide content of the sample was related closely to the number of grafts in initiation. The number was estimated as 17 times for thermal initiation and 6 times for photoinitiation at the maximum values. The CMC peroxide showed a marked activity toward photografting of acrylamide, acrylic acid, acrylonitrile, and vinyl acetate on the substrate. | Statistically designed experiments have been made using partial carboxymethylated cotton fabric. The effects of three reaction parameters (concentrations of sodium hy droxide and monochloroacetic acid and time period) on wet pickup and carboxyl content are presented using polynomial models. Monochloroacetic acid concentration seems to be the leading factor among the parameters investigated. Poor reproducibility of the drying process could be one possible barrier to industrial applications of car boxymethylation. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 21,595 |
Copolymer ethylene-dimethyl-aminoethyl methacrylate (EDAM) with 3.9% DAM side groups and ultra-high molecular weight polyethylene (UHMWPE) were blended in decalin solvent. The hot homogenized solution was poured into an aluminum tray to form gels and the decalin was allowed to evaporate from the resultant gels under ambient condition. Surprisingly, the resultant dry blend films could be elongated to more than 200-fold (λ=200) even for the blend film with 90% EDAM content (9/1 composition), although the maximum draw ratio of EDAM homopolymer films was 1.6-fold (λ=1.6). The mechanism of the great drawability was dependent upon the content of EDAM. The drawability for the 9/1 composite films was attributed to large crystal lamellae of UHMWPE ensuring crystal transition from a folded to a fibrous type. Accordingly, EDAM chains were independent of ultradrawing of UHMWPE and kept a random orientation under ultra-drawing process. The storage (Young's) modulus was 10 GPa at 20 °C. In contrast, EDAM chains within the 1/1 composite films were oriented drastically together with UHMWPE crystallites. The modulus of the 1/1 composition at 20 °C reached 68 GPa, which was higher than the value (40 GPa) of polypropylene films with λ=100. Such considerable difference of modulus due to EDAM content was analyzed in relation to the gelation/crystallization from solutions. | An investigation was reported on the effect of foaming parameters on the microstructure, mechanical properties, and thermal conductivity of low-density polyethylene (LDPE) foams containing various amount of ultrahigh-molecular-weight-polyethylene (UHMWPE) as a reducer of chemical cross-linking. Azodicarbonamide (ADCA) and dicumyl peroxide (DCP) were used as foaming agent and cross-linking agent, respectively. The LDPE/UHMWPE blends were prepared in an internal mixer and foamed using a single-stage compression molding technique. Considering various parameters and their levels, optimization of Taguchi experimental design was carried out, an L9 orthogonal standard array was selected and the efficient levels for different variables were calculated using analysis of variance (ANOVA) of the results. Also due to different objective functions investigated in this process, optimization of overall evaluation criteria (OEC) method was used. The results revealed that addition of UHMWPE leads to a significant increase... | The USACE-Norfolk District (NAO) and the City of Petersburg, VA are working toward restoring the former Appomattox River Federal Navigation Channel. In this effort, ~350,000 cubic yards of deposited sediment will be removed from -14 feet MLLW up to + 6 feet MLLW over a ~1 mile reach of the Appomattox River. Historical industrial uses have resulted in PAH contamination exceeding 500 mg/kg on average, with hotspots detected in excess of 5,000 mg/kg based on USACE 2004 analytical data. To support the NAO with its assessment of contaminant distribution, upland source control measures, dredge sequencing, sediment capping requirements to address residual contaminants and beneficial reuse options for the dredged material have been evaluated. In support of beneficial reuse as agricultural soil, a lab treatability study has been completed to assess biodegradation potential. Total PAH concentrations in three laboratory test pans after 46 weeks of treatment indicated an overall 80% contaminant reduction using an enhanced bioremediation process. The results of this bench-scale study were used as the basis for the design of a pilot field-scale landfarm study demonstration undertaken during July 2007. After five months of treatment, LMW PAHs in landfarm material appear to have degraded first while HMW PAHs are degrading more slowly, a process which generally mimics the results of the laboratory investigation. Conclusions based on the laboratory and landfarm activities as well as the technical and regulatory issues that must be resolved to allow eventual placement of the material at a mine reclamation site for revegetation purposes will be presented. | eng_Latn | 21,596 |
This paper reports on the use of variable frequency microwave processing to uniformly heat and post-cure large (>100 cm 2 ) plates of thermoset polymer matrix composite (PMC) material consisting of isocyanate/epoxy mixtures. Prior work has indicated that microwave energy is capable of reducing the time or the temperature necessary to achieve full cure; however, single-frequency microwave heating results in non-uniformity of heating/curing in areas of over 12.5 cm 2 . By using a Variable Frequency Microwave Furnace and sweeping the microwave power over the 5 to 6 GHz frequency range at a power level of 150 Watts, uniform heating and curing of the PMC plates was achieved over an area of greater than 100 cm 2 -- and a volume of greater than 200 cm 3 . The overall temperature gradient across the surface of the plates was less than 10%. Finally, this paper also reports on observed, volume-related heating effects, which are postulated to be the result of heat loss from the sample surface. | Variable frequency microwave (VFM) curing has been investigated as a rapid cure method for the polyimide 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride / P-Phenylenediamine (BPDA/PPD). Previous studies, involving curing of this polyimide using rapid thermal heating, have resulted in undesirable properties such as high residual stress. In this study, BPDA/PPD films produced using VFM curing (cure time ranging from 600-1800s) are compared with film produced via a conventional thermal cure (cure time of 18000s) and a rapid hotplate cure (cure time ranging from 1200-3600s). Properties, including dielectric constant, residual stress, modulus, solvent resistance, tensile strength, and coefficient of thermal expansion were measured for the films produced by each of the three techniques. The results of this study indicate that VFM curing can provide thin film properties similar to those achieved via lengthy, (conventional) thermal curing. In addition, for the first time, low residual stress BPDA/PPD polyimide has been created via a rapid cure process. Hence, it can be concluded that VFM curing is a viable method for more rapid production of BPDA/PPD polyimide film. | The design and correction factor evaluation of a WR-15 (50 to 75 GHz) rectangular waveguide microcalorimeter is presented. This new microcalorimeter will be the US national standard for power from 50 to 75 GHz. It can measure the effective efficiency of a wider variety of transfer standards than can the previous microcalorimeter. It has also been designed so that its correction factor can be experimentally evaluated by multiple techniques. | eng_Latn | 21,597 |
Ionic polymer metal composites (IPMCs) are electroactive materials made of ionic polymer thin membranes with platinum metallization on their surfaces. They are interesting materials due to not only their electromechanical applications as transducers but also to their electrochemical features and the relationship between the ionic/solvent current and the potential field. Their electrochemical properties thus suggest the possibility for exploiting them as compact fractional-order elements (FOEs) with a view of defining fabrication processes and production strategies that assure the desired performances. ::: In this paper, the experimental electrical characterization of a brand new IPMC setup in a fixed sandwich configuration is proposed. Two IPMC devices with different platinum absorption times (5 h and 20 h) are characterized through experimental data: first, a preliminary linearity study is performed for a fixed input voltage amplitude in order to determine the frequency region where IPMC can be approximated as linear; then, a frequency analysis is carried out in order to identify a coherent fractional-order dynamics in the bode diagrams. Such analyses take the first steps towards a simplified model of IPMC as a compact electronic FOE for which the fractional exponent value depends on fabrication parameters as the absorption time. | The paper presents a fractional order model of a heating process and a comparison of fractional and standard PI controllers in its closed loop system. Preliminarily, an enhanced fractional order model for the heating process on non-continuous materials has been identified through a fitting algorithm on experimental data. Experimentation has been carried out on a finite length beam filled with three non-continuous materials (air, styrofoam, metal buckshots) in order to identify a model in the frequency domain and to obtain a relationship between the fractional order of the heating process and the different materials’ properties. A comparison between the experimental model and the theoretical one has been performed, proving a significant enhancement of the fitting performances. Moreover the obtained modelling results confirm the fractional nature of the heating processes when diffusion occurs in non-continuous composite materials, and they show how the model’s fractional order can be used as a characteristic parameter for non-continuous materials with different composition and structure. Finally, three different kinds of controllers have been applied and compared in order to keep constant the beam temperature constant at a fixed length. | The oxidative polymorphism of debrisoquine (DBQ) has been determined in 89 patients with colo-rectal cancer and in 556 normal control subjects. Four patients and 34 controls, with a metabolic ratio >12.6, were classified as poor metabolisers of DBQ (n.s.). | eng_Latn | 21,598 |
The successful production of novel biodegradable plastic copolymers incorporating both synthetic plastic formulations, such as polystyrene, and naturally occurring biodegradable polymer components, such as cellulose, starch, or xylan, requires stable chemical bonding between these polymers. Modification of the natural polymers through acetylation of the available hydroxyl groups permits the formation of appropriate film-forming plastic copolymers. However, modification of natural polymers has been demonstrated to result in decreased attack by microbial catalysts. For this study, the abundant natural polymers cellulose, starch, and xylan were substituted with acetate to various degrees, and the effect of this modification on the anaerobic biodegradation was assessed using the biochemical methane potential (BMP) protocol. Significant reduction in anaerobic biodegradability resulted with all polymers at substitution levels of between 1.2-1.7. For the xylan acetate series, the trends for anaerobic biodegradation were in good agreement with reduced enzymatic hydyolysis using commercially available xylanase preparations. | Plastic waste is an issue of global concern because of the environmental impact of its accumulation in waste management systems and ecosystems. Biodegradability was proposed as a solution to overcome this problem; however, most biodegradable plastics were designed to degrade under aerobic conditions, ideally fulfilled in a composting plant. These new plastics could arrive to anaerobic environments, purposely or frequently, because of their mismanagement at the end of their useful life. This review analyzes the behavior of biodegradable and conventional plastics under anaerobic conditions, specifically in anaerobic digestion systems and landfills. A review was performed in order to identify: (a) the environmental conditions found in anaerobic digestion processes and landfills, as well as the mechanisms for degradation in those environments; (b) the experimental methods used for the assessment of biodegradation in anaerobic conditions; and (c) the extent of the biodegradation process for different plastics. Results show a remarkable variability of the biodegradation rate depending on the type of plastic and experimental conditions, with clearly better performance in anaerobic digestion systems, where temperature, water content, and inoculum are strictly controlled. The majority of the studied plastics showed that thermophilic conditions increase degradation. It should not be assumed that plastics designed to be degraded aerobically will biodegrade under anaerobic conditions, and an exact match must be done between the specific plastics and the end of life options that they will face. | The application of four different conducting polymers (polypyrrole, poly-N-methylpyrrole, poly-5-carboxyindole and polyaniline) as sensors for organic vapours has been investigated. ::: ::: The sensors are formed by the electrochemical polymerization of the appropriate monomers across a 12 μm gap between two gold microband electrodes. Upon exposure to vapours the polymers show conductivity changes that are rapid and in general reversible at room temperature. ::: ::: Of the four polymers investigated, under the deposition conditions employed and for the vapours used (methanol, ethanol, acetone, ether and toluene), poly-5-caboxyindole is found to give the most stable, reproducible behaviour and to be the most promising material for sensor applications. The use of these materials in intelligent gas sensors is discussed. | eng_Latn | 21,599 |
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