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As the aerospace industry has continued to evolve from the era of the Wright brothers, so too have aerospace structural materials. And it appears that a new inflection point requiring [...]

Miguel Jose Yacaman is known for his skills with developing electron microscopy techniques for understanding the structure of particles at the nanometer scale. He's a professor of applied physics and [...]

Historians often find that the most intriguing details are hidden in the footnotes. That was the case when historian of science Galina Shyndriayeva found an unexamined connection between two prominent [...]

Crystallization is critical in producing various substances in the food and pharmaceutical industries. The process begins with nucleation from a supersaturated solution, followed by the directed movement of solute molecules toward the newly formed nuclei. This movement is influenced by different factors such as molecular attraction and thermodynamic properties, which influence the resulting crystal size and shape. This paper presents an automated monitoring approach for the growth process of crystallization from saturated solutions. To monitor such a process, a combination of artificial intelligence and computer vision is used. The approach was developed for application in material research to automate the processing of numerous samples, which would otherwise require laboratory personnel. [ABSTRACT FROM AUTHOR]

Hydrogel has a wide range of functionalities and great potential for application in various fields. However, the disadvantages such as weak strength and susceptibility to water loss limit its application in complex environments. In this study, glycerol and water were used as binary solvents to construct dual-network hydrogels by mixing polyvinyl alcohol (PVA) and the natural polymer gelatin (GEL) through a simple one-pot method. Glycerol was introduced to form hydrogen bonds with PVA and GEL, on the one hand, resulting in the excellent mechanical properties of the prepared hydrogels; on the other hand, glycerol also endowed the hydrogels with excellent anti-drying and anti-freezing properties, which enabled them to be stably applied in extreme environments. In addition, by adjusting the proportion of glycerol, the mechanical properties of the hydrogel can be adjusted to adapt to the applications in different scenarios. This kind of organic hydrogel with adjustable mechanical properties for anti-drying and anti-freezing has great potential for development in various fields. Highlights * Organic hydrogels with high mechanical strength were prepared by the one-pot method. * The anti-drying and anti-freezing gel is suitable for extreme conditions. * The multifunctional gel is removable and can be reused to save costs. KEYWORDS dual network hydrogel, hydrogen bonding, mechanical properties, polyvinyl alcohol, 1 | INTRODUCTION Hydrogels are three-dimensional polymer networks containing large amounts of water, and most of them have high water content, biocompatibility, and functionality. (1) Hydrogels with excellent mechanical properties [...]

Thermoplastic vulcanizates show significant anisotropic mechanical properties when processed to components via injection molding. This effect is related to a process-dependent distortion of the incorporated elastomer particles in high-shear regions during the injection phase. In a plate geometry, the elastomer particles in the shear regions are oriented and deformed in the flow direction. However, the ongoing distortion processes and the influencing factors of the process parameters on the resulting phase morphology and mechanical response are not entirely understood. Therefore, in this study, the effect of the injection molding machine settings for the production of a plate component on the local phase morphology and mechanical anisotropy is investigated. The investigations are conducted on two commercial material grades with different Shore-A hardness 30 and 90. A significant inverse effect of the injection volume flow rate on the particle distortion and anisotropy is found. Increasing the volume flow rate results in a reduction of the anisotropy. This is counterintuitive from the experience of other materials with process-dependent anisotropy. Also, a significant influence of the process on the overall stiffness of the compounds is observed. Highlights * Sturcture-property relation for phase morphology in thermoplastic vulcanizates * Quantitative microstructure analysis in injection molded plates * Macroscopic analysis of anisotropic mechanical response under uniaxial loading * Effect analysis of injection molding parameters on the mechanical anisotropy * Additional effects of process settings on overall stiffness of the material KEYWORDS anisotropy, phase morphology, thermoplastic vulcanizates, 1 | INTRODUCTION Thermoplastic vulcanizates (TPV) are a subcategory of the thermoplastic elastomer (TPE) material class. TPV are polymer blends consisting of vulcanized elastomer particles embedded in a thermoplastic matrix [...]

The present study article aims to clarify the effect of colloidal polystyrene (PS) latexes with a broad particle size distribution on film formation kinetics of multi-walled carbon nanotube (MWCNT)-added polymer nanocomposites by considering theoretical film formation models. Experimentally, light transmitted from nanocomposite films, each having different weight fractions of MWCNT, was recorded at different annealing temperatures via UV-Visible spectrophotometry. Optical data set was then theoretically elaborated by taking into account void closure and Prager-Tirrell models. Activation energies of viscous flow ([DELTA]H) and backbone motion for reptating PS chains ([DELTA][E.sub.B]), minimum film formation ([T.sub.0]) and healing (T h) temperatures were then computed from optical data. Experimental results revealed that [DELTA]H required for void closure phenomenon remained unaffected by both nanofiller and size distribution of latexes. On the other hand, it was found that [DELTA][E.sub.B] for backbone motion promoted upon the addition of nanofillers into latex particles. Our experimental findings suggested that film formation from MWCNT-added latex films with a broad particle size distribution mainly originates from void closure mechanism since [DELTA]H for viscous flow suppresses [DELTA][E.sub.B] acquired for backbone motion of repeating PS chains to a great extent. Highlights * A broad size distribution effect of PS on film formation was investigated. * Voids closure and Prager-Tirrell models were applied to spectroscopic data. * Activation energy of viscous flow is unaffected by size distribution of PS. * Latex film formation with varying size distribution stems from void closure. KEYWORDS film formation, interdiffusion, light transmission, particle size distribution, void closure, 1 | INTRODUCTION Understanding film formation mechanisms of colloidal latex particles plays a pivotal role in fabrication of new-generation nanomaterials with improved features that can be potentially integrated into film [...]

Based on the stress fluctuation during the tensile process of poly(butylene succinate) (PBS), the tensile behavior of biodegradable bicrystalline block copolyesters (PBSEG) synthesized using polycondensation of poly(ethylene glycol) (PEG) and poly(butylene succinate) (PBS) was further studied. The effects of tensile rate and temperature test conditions on the stress-strain behavior of bicrystalline block copolymer PBSEG were investigated by conducting tensile tests. The experimental results showed that when the mass content of polyethylene glycol in PBSEG was 60%, the material did not show obvious periodic stress fluctuation during the 'cold drawing' stage of the stress-strain curve, but showed different and more complicated periodic curve changes. The stress fluctuation of PBSEG copolyester had the characteristics of small amplitude and short period. The elongation at break increased obviously, and the maximum elongation at break was more than 2000%. The analysis of morphology and structure showed that the surface morphology of PBSEG dumbbell bars did not show obvious alternating changes in structure, characterized by light and dark. Craze was the main cause of ductile fracture for PBS and PBSEG copolyesters. The tensile fracture of the two materials occurred in the stress fluctuation region. Highlights * Small-amplitude and short-period stress fluctuation for PBSEG copolyester. * There was no alternating light and dark on the surface of the PBSEG stretched spline. * Craze was the main cause of ductile fracture for PBS and PBSEG copolyesters. * Tensile fracture of the materials occurred in the stress fluctuation region. KEYWORDS bicrystalline block copolymer, craze, poly(butylene succinate), poly(ethylene glycol), stress fluctuation, 1 | INTRODUCTION Some thermoplastic polymers exhibited a special tensile behavior during the stretching process. In the stretch neck stage, the stress was no longer constant, but showed a periodic [...]

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ADHESIVE-FREE METHOD JOINS WOOD AND METAL Researchers at Graz University of Technology, Austria, achieved an extremely strong bond of wood with both metal and polymer composites by using 3D printing [...]

Wherever coal mining occurs, so do coal seam and coal mine fires. Besides depleting non-renewable resources, coal fires create health hazards through venting of hot combustion gases and toxic fume emissions, create large surface cracks, fissures and other subsidence openings as the coal burns, trigger wildfires and have forced entire communities to be abandoned. Unfortunately, the same properties that make coal valuable as a fuel source make these fires extremely difficult to extinguish. Each coal fire is unique and the extinguishment method or combination of methods that offer the best opportunity for success will be a function of the local site conditions and length of time the fire has been burning. As a result, it is important to understand the specific instances or situations in which various mine fire abatement techniques have been successful. Equally as important, is a detailed understanding of the reasons or cause for failure under conditions and in situations for which the methods used were unsuccessful. To aid in this process, this paper provides an overview of coal mine fire extinguishment methods, their applicability to various active or inactive mining situations, and relative effectiveness based on published results where possible. This review can serve as an initial screening tool and also hopefully promote research into more reliable and cost-effective extinguishment methods.

Gel foam extinguishing agent (gel foam) has promising applications in the prevention and management of mine coal spontaneous combustion. Based on the research on coal spontaneous combustion and prevention technology, this article discusses recent studies on using gel foam to extinguish coal mines. The structural properties and principles of gel foam are described briefly. The research developments of three significant varieties of gel foam are then presented in detail, including silicate gel foam, acrylamide copolymer gel foam, and natural polymer gel foam. Meanwhile, the research status of gel foam anti-fire technology's rheological properties, stability property, plugging property, and inhibitory properties are introduced. Furthermore, in conjunction with the research state, the prospects of the research direction of gel foam are proposed, which serve as a reference for future research on gel foam. [ABSTRACT FROM AUTHOR]

In industrial sectors like medical and automotive engineering, the demand for metal components with a high function integration brings conventional production technologies to their limits. This motivates research on innovative processes, which can meet the present requirements on fabricated parts and consequently also the demands on the applied manufacturing process. Part-sided, a high strength, narrow dimensional tolerances and a large functionality is often desired. In addition, an economical component production calls for processes with high material utilization as well as the achievement of short cycle times. The process class of sheet-bulk metal forming, characterized by the application of bulk forming operations on sheet metal, offers the potential to meet these requirements. Currently, sheet-bulk metal forming is mainly used for the fabrication of components with functional elements of macroscopic size. However, microscopic elements and micro-textured surfaces are of high interest for applications in prosthetics and automotive engineering. The objective of this study is therefore to develop an application-oriented method for the design, production and testing of 16MnCr5 metal components, manufactured by a combined process of sheet-bulk metal forming, creating a defined microstructure on the surface. Since the selection of a suitable texture layout and geometry is crucial for tribological optimization, these are designed for their application using numerical elastohydrodynamic lubricant simulations. The contact conditions occurring in the application are modelled as realistically as possible so that texture designs suitable for production can subsequently be compared in test bench trials. It is shown that the tappets produced by forming technology can be efficiently investigated with the test rig presented. [ABSTRACT FROM AUTHOR]

SELF-ASSEMBLING CRYSTAL STRUCTURES Scientists at Cornell University, Ithaca, N.Y., used a targeted computational approach to find more than 20 new self-assembled crystal structures. The team conducted a targeted search for [...]

ECOFRIENDLY 3D-PRINTED LIGNIN COATING Researchers at the German Institutes of Textile and Fiber Research Denkendorf (DITF) are using a 3D-printing process to make a coating for gloves that is an [...]

This comprehensive review investigates the multifaceted applications of machine learning in materials research across six key dimensions, redefining the field's boundaries. It explains various knowledge acquisition mechanisms starting with supervised, unsupervised, reinforcement, and deep learning techniques. These techniques are transformative tools for transforming unactionable data into insightful actions. Moving on to the materials synthesis, the review emphasizes the profound influence of machine learning, as demonstrated by predictive models that speed up material selection, structure-property relationships that reveal crucial connections, and data-driven discovery that fosters innovation. Machine learning reshapes our comprehension and manipulation of materials by accelerating discovery and enabling tailored design through property prediction models and structure-property relationships. Machine learning extends its influence to image processing, improving object detection, classification, and segmentation precision and enabling methods like image generation, revolutionizing the potential of image processing in materials research. The most recent developments show how machine learning can have a transformative impact at the atomic level by enabling precise property prediction and intricate data extraction, representing significant advancements in material understanding and innovation. The review highlights how machine learning has the potential to revolutionize materials research by accelerating discovery, improving performance, and stimulating innovation. It does so while acknowledging obstacles like poor data quality and complicated algorithms. Machine learning offers a wide range of exciting prospects for scientific investigation and technological advancement, positioning it as a powerful force for influencing the future of materials research.

Copyright of Eurasian Physical Technical Journal is the property of E.A. Buketov Karaganda University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In finite element analysis of steel-reinforced elastomeric bearings (SREB) under compression, modeling of rubber as a nearly or fully incompressible material requires special attention. In this study, finite element simulations of circular elastomeric pads and rectangular SREB under compression were performed to analyze the effects of rubber compressibility with respect to different pad geometries and shape factor values. The ratio of the compressive modulus for a compressible rubber to that of an incompressible rubber was also introduced based on the previously derived exact solutions as well as the ad hoc approximations. This ratio accurately represents the influence of compressibility on compressive stiffness in terms of relative compressibility (K/G) and shape factor values. Numerical results were also compared with the experimental results on rectangular SREB with moderate shape factors. Recommended values for relative compressibility of carbon black-filled rubbers in the range of 50-200 result in underestimated compressive stiffness, especially for bearings with shape factor values greater than five. It is recommended to adjust the relative compressibility, considering the shape factor, so that the compressive stiffness does not decrease by more than 50% compared to the incompressible case. KEYWORDS bulk modulus, compressibility, compressive modulus, finite element analysis, rubber, shape factor, steel-reinforced elastomeric bearing, 1 | INTRODUCTION Elastomeric bearings allow displacement and rotation of individual parts of the supported structure by deformation of the elastomeric material, that is, rubber. Because of their relatively low [...]

The effect of iron-containing substances with different forms on the properties of carbon-black filled natural rubber compound is discussed. The ionic iron substances (Fe[Cl.sub.2], Fe[Cl.sub.3], Fe[(SA).sub.3]) have a detrimental effect on the rubber. Based on the oxidation induction temperature values, the relative deteriorating effects of ionic iron substances on the rubber are in the order: Fe[(SA).sub.3] > Fe[Cl.sub.3] [approximately equal to] Fe[Cl.sub.2]. Not only are the metal ions ([Fe.sup.2+], [Fe.sup.3+]) with adjacent stable oxidation states catalytically active in degrading rubber, but also the counterions have an influence on the effect of oxidation, particularly the stearic anion. Ionic iron materials can decrease the molecular weight, especially for the case of Fe[(SA).sub.3] as measured by gel permeation chromatography. Due to the degrading effect on the rubber molecules, Fe[(SA).sub.3] brings about a torque decrease in moving die rheometer and evident decrease of the Mooney viscosity at 100[degrees]C, which is different from the effects of [Fe.sub.2][O.sub.3] and 304L-Fe. The insoluble iron substances behave more like hard fillers. Additionally, Fe[(SA).sub.3] remarkably alters the bound rubber content and the tensile properties after aging via two different process (scission and crosslinking). Overall, this work has a thorough comparison of effect of iron-containing materials on rubber aging and provides useful inspiration to protect the rubber from deterioration by foreign reagents and regulating the rubber stability and degradation rate via introducing degradative metal ions. KEYWORDS aging, GPC, ionic iron substances, natural rubber, OIT, 1 | INTRODUCTION Investigation of mechanism on rubber autoxidation (degradation) is important in maintaining the lifetime/stability of rubber materials and developing the easy-degradable polymer material. Rubber degradation involves chain initiation, [...]

Maleic anhydride-grafted-polyethylene was dynamically cross-linked via reactive melt blending with 4,4'-dithiodianiline. Thermal and mechanical properties of polyethylene vitrimers with different cross-linking density were investigated. The results indicate that the degree of crystallinity decreased with increasing cross-linking density. This behavior was directly related to short-term and long-term mechanical properties: vitrimers showed a decrease in yield strength and creep performance. The yield strength of PE vitrimers decreased linearly in relation to the degree of crystallinity. Polarized optical microscopy revealed that the cross-links inhibit the growth of spherulites structure in polyethylene vitrimers. Thermogravimetric analysis indicated an increase in the onset degradation temperature and decomposition rate for vitrimers with increased cross-linking density. The stiffness of the vitrimers decreased with increasing cross-linking density which led to higher damping properties. Finally, it was demonstrated that reprocessing of polyethylene vitrimer was possible without significant impact in mechanical properties. KEYWORDS cross-linking, mechanical properties, polyethylene, reprocessing, structure-property relations, thermal properties, vitrimers, 1 | INTRODUCTION Polyethylene (PE) is presently the most-used commodity plastic by volume and it is frequently used in consumer goods, construction, and electrical industry. [1,2] Some examples include plastic [...]

The effect of an in-mold static mixer on the optical properties of polystyrene (PS) parts was explored within the injection molding process. Several mixers were assessed via simulation and molding trials to identify the mixing ability and effect on optical properties including retardation and birefringence. It was found that the static mixers within the runner could successfully mix the polymer and disrupt property distributions including temperature but that there was only a slight improvement in retardation with some of the mixer cases. The experiments and simulations showed relatively good correlation in results although there were slight differences in the trends that could be due to the experimental measurement resolution or unaccounted-for variables between the experiments and simulations. The retardation was experimentally measured using a custom-made polariscope using photography and image processing. These experiments indicated that the use of a static mixer within the runner system of a mold could be used for homogenizing the polymer melt after the plasticizing unit. However, its effect on improving the optical performance of injection molded parts could be offset by the melt flow downstream of the static mixer and the potential increase of residual stresses due to flow restriction, suggesting the importance of mixer location and geometry. KEYWORDS birefringence, injection molding, plastic optics, retardation, simulation, static mixer, 1 | INTRODUCTION Improving the quality and accuracy of injection molded parts has been an objective since the injection molding machine was developed in the nineteenth century. [1] Polymers, and [...]

In recent years, additive manufacturing (AM) processes have allowed the building of complex parts and objects with favorable geometric shapes without the need for fabricating special tools. In AM, objects are built layer by layer. Advantages include the possibility of forming complex shapes, reduced waste, no special requirements, and so forth. A critical parameter to consider in AM technologies is the processing (printing) speed, which, if increased, can reduce production (printing) time and expenses. Thus, speeding up the production time in AM has always been paramount. In recent years, fused filament fabrication (FFF) has been extensively developed due to straightforward processing, reliability, and ability to build complex objects and parts from thermoplastic materials. In addition to simplicity, this method has some shortcomings, including low printing speed and instability during the rasters deposition when speeding up the printing process, which is investigated in this study. The results showed that the nozzle height from the work-piece surface and nozzle diameter play a critical role in the process instability. Additionally, there is a critical limit in the formation of molten instability independent of the printing speed. Furthermore, the effect of printing speed on tensile strength was investigated. The results showed that optimizing the nozzle temperature and the extra extrusion multiplier allows printing a high-quality part having optimum tensile and mechanical properties by the maximum printing speed. KEYWORDS additive manufacturing, extra extrusion multiplier, fused filament fabrication, instability, nozzle temperature, printing speed, tensile strength, 1 | INTRODUCTION One of the spectacular techniques of additive manufacturing (AM) is fused filament fabrication (FFF) which extensively has progressed during the last decades. [1-5] Many scholars have been [...]

The material behavior of the API-60 epoxy resin was investigated using atomistic molecular dynamics simulations. In this study, a hybrid, reactive force field (M-GAFF2), which combined Morse and harmonic bond potentials from GAFF2, was developed to understand the elastic/plastic response of the cured epoxy polymer. We found that elastic deformation was caused by epoxy network rearrangement at low strain while plastic deformation was observed by stretching and breaking covalent bonds after the yield point. Ab initio calculations at the CASPT2(2,2)/6-311+G** level of theory were performed to compute parameters for M-GAFF2. These are necessary for breaking covalent bonds in the epoxy network backbone when they are deformed. The M-GAFF2 was effective in revealing the ductile-like deformation behavior of the crosslinked epoxy polymer at the microscopic level, including elastic/plastic deformations and progressive failure. The effect of testing temperature at 300 and 400 K and degree of cure (DoC) on tensile properties such as Young's modulus, ultimate strength, and failure strain was evaluated to verify the feasibility of the M-GAFF2 in different thermodynamic constraints. This new approach is easy to use for nonequilibrium MD simulations and computationally efficient for studying the microscopic deformation and failure behavior of thermosetting polymers at the atomistic scale. KEYWORDS epoxy polymer, fracture mechanism, hybrid force field, molecular dynamics simulations, 1 | INTRODUCTION Molecular dynamics (MD) simulations are widely used to understand the complex phenomena of epoxy polymers associated with their atomistic- and molecular-level structures. Both quantitative and qualitative equilibrium [...]

In this study, the tribological properties of drawn PTFE were tested on a CSM tribometer at room temperature and cryogenic temperature. The orientation degree and worn surface morphology of drawn PTFE were studied and correlated with the friction and wear behaviors. It was found that the sample with low friction coefficient corresponded to high orientation degree in the parallel direction at room temperature, while the friction coefficient barely changed with increasing draw ratio in the perpendicular direction. The friction coefficient of drawn PTFE at liquid nitrogen temperature is higher than that at room temperature in the perpendicular direction, while the two values are almost undistinguishable within error range in the parallel direction. The wear volume of drawn PTFE at liquid nitrogen temperature is lower than that at room temperature in both perpendicular and parallel directions due to the mitigation of adhesive wear of drawn PTFE under liquid nitrogen temperature. KEYWORDS cryogenic temperature, friction and wear, orientation, polytetrafluoroethylene, 1 | INTRODUCTION The harsh space environment including wide temperature ranges from cryogenic to high temperature, strong radiation, and high vacuum limits the use of conventional liquid lubricants and greases [...]

METALS CHALLENGE QUANTUM STATUS QUO A team of researchers led by James Rondinelli at Northwestern University, Evanston, III., unveiled a class of metals that challenges the status quo of how [...]

Green innovation involves creating new solutions to environmental problems and sustainable development, and research and development of innovative technologies in the fields of the environment, resources, and energy is being conducted worldwide to create a low-carbon and circular society. We interviewed Yoshitaka Taniyasu, a senior distinguished researcher at NTT Basic Research Laboratories, who has produced world-class research results concerning functional materials for green innovation, about his achievements and attitude as a researcher. [ABSTRACT FROM AUTHOR]

Single phase cartridge brass, C26000, an alloy composition of 70% copper and 30% zinc, was selected as the material of choice to create an entry for the 2021 International Metallographic [...]

MULTIFUNCTIONAL MAGNETIC MATERIAL A research team from Australia's Flinders University created a new material that can be moved remotely with a magnet. The multifunctional material, made from magnetic iron particles [...]

ULTRA-HIGH-RATE COATING TECH Using vacuum plasma, a research team from Toyohashi University of Technology, Japan, created an ultra-high-rate coating technology for functional hard carbon films. Due to their low friction [...]

Researchers at the University of Illinois Urbana-Champaign have used machine learning, optimization, 3D printing, and stress experiments to create a material that mimics bone. The group started with a materials [...]