Full-density bulk nanocomposites have been developed in the immiscible Cu-Fe system through a powder metallurgy route. Elemental copper and iron powders were first mechanically alloyed to form single-phase, nanocrysta...
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Full-density bulk nanocomposites have been developed in the immiscible Cu-Fe system through a powder metallurgy route. Elemental copper and iron powders were first mechanically alloyed to form single-phase, nanocrystalline, metastable solid solutions, Cu100-xFex (x=0 to 100). These solid solutions were subsequently decomposed into Cu/Fe two-phase domains of various volume fractions during the hot consolidation process,forming in situ nanophase Cu-Fe composites. Full-density compacts have been produced at relatively low consolidation temperatures (< 500 degrees C) by employing sinter forging at high applied pressure and a protective atmosphere. Such a consolidation scheme, coupled with enhanced grain size stability due to the unique microstructural evolution sequence involved, retained the grain sizes in the nanometer range for both Cu and Fe grains in the composite products. Fully dense composite specimens exhibit enhanced microhardness as compared with rule-of-mixtures predictions. This enhancement is attributed to interface strengthening at fcc-bcc interphase boundaries.
Sexual selection is thought to play a major role in the evolution of color due to the correlation between a signaler’s physiological state and the displayed *** such,researchers often investigate how color correlates...
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Sexual selection is thought to play a major role in the evolution of color due to the correlation between a signaler’s physiological state and the displayed *** such,researchers often investigate how color correlates to the quality of the ***,research on the relationship between color and individual quality is often taxonomically limited and researchers typically investigate how color phenotypes relate to one index of quality,such as a linear measure of body ***,we investigated the relationship among body size,claw size,claw muscle mass,lipid content,and the color of the claw in male fiddler crabs(Leptuca uruguayensis)which wield an exaggerated claw that varies in color from brown to *** hypothesized that if the color was correlated to one or more indices of male quality,the color displayed on the claws of male *** could be under sexual *** found *** claw color varies substantially among the individuals we ***,we did not find a correlation between claw color and indices of quality;neither brightness nor hue correlated to the indices of quality we *** findings suggest that claw color in *** is unlikely to have evolved to signal quality,but may instead function as a species identity or as a non-indicator sexual signal.
AbstractThe drawing of polymers into high strength films or tapes is an important process in industry. A method of local heating and drawing of plastic sheets into high strength films is discussed, and the preliminary...
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AbstractThe drawing of polymers into high strength films or tapes is an important process in industry. A method of local heating and drawing of plastic sheets into high strength films is discussed, and the preliminary results of this new technology are presented.
The extrusion of blown film polyethylene is a complex process characterized by a large number of interdependent process variables. In order to derive the set of process conditions necessary for a desired film solid st...
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The extrusion of blown film polyethylene is a complex process characterized by a large number of interdependent process variables. In order to derive the set of process conditions necessary for a desired film solid state property, the processor normally utilizes a laborious trial‐and‐error method. In this work, a technique is described to establish more directly the set of extruder settings for producing film with an optimum value of a given property. Biaxial toughness was optimized in the present work, but the technique is applicable to any quantifiable film property.
Thermodynamics of(001)epitaxial ferroelectric films completely relaxed due to the formation of elastic domains with a three-domain architecture is *** polydomain structure and electromechanical response of such films ...
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Thermodynamics of(001)epitaxial ferroelectric films completely relaxed due to the formation of elastic domains with a three-domain architecture is *** polydomain structure and electromechanical response of such films are analyzed for two cases corresponding to immobile and mobile elastic domain *** is shown that immobile elastic domains provide additional constraint which increases the mechanical and electrical clamping,thereby significantly reducing the piezoelectric and dielectric *** the other hand,a polydomain ferroelectric film adapts to the variations in the applied electric field by reversible domain wall displacements in the case of mobile domain *** comparison of the theory with experiments shows that the elastic domain walls are mobile in the fully relaxed films of~1μm *** addition,if the substrate constraint is reduced via decreasing lateral size of a polydomain ferroelectric film,its piezoresponse will increase dramatically,as is experimentally verified on small islands of polydomain ferroelectric *** general conclusions can be readily applied to other constrained polydomain films.
Rare earth chalcogenides provide a great platform to study exotic quantum phenomena such as superconductivity and charge density waves. Among various interesting properties, the coupling between magnetism and electron...
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A statistical model for steady-state sliding wear of the metal counterpart in metal-composite systems has been extended to include composite reinforcement size and size distribution. It has been shown that the wear ra...
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A statistical model for steady-state sliding wear of the metal counterpart in metal-composite systems has been extended to include composite reinforcement size and size distribution. It has been shown that the wear rate of the metal counterpart under conditions where MMC wear is characterized by plastic deformation (microplowing) is controlled by the ratio between the mean of particulate radius squared and the square mean particulate radius, E(r(2))/E(r)(2), a descriptor of the particulate size and distribution. Under these instances, e.g. for 4, 10 and 13 mu m particulate discontinuously reinforced aluminum (DRA)/17-4 PH tribosystems, the modified statistical model permits accurate prediction of the wear performance of the unreinforced counterpart. However, when MMC wear involves reinforcement cracking and delamination, the model overestimates the wear rate of the counterpart, i.e. in the 29 mu m Al-SiCp/17-4 PH tribosystems.
A new class of high-entropy M3B4 borides of the Ta_(3)B_(4)-prototyped orthorhombic structure has been synthesized in the bulk form for the first *** with compositions of(V0.2Cr0.2Nb0.2Mo0.2Ta0.2)3B4 and(V0.2Cr0.2Nb0....
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A new class of high-entropy M3B4 borides of the Ta_(3)B_(4)-prototyped orthorhombic structure has been synthesized in the bulk form for the first *** with compositions of(V0.2Cr0.2Nb0.2Mo0.2Ta0.2)3B4 and(V0.2Cr0.2Nb0.2Ta0.2W0.2)_(3)B_(4) were fabricated via reactive spark plasma sintering of high-energy-ball-milled elemental boron and metal *** sintered specimens were〜98.7%in relative densities with virtually no oxide contamination,albeit the presence of minor(4-5 vol%)secondary high-entropy M5B6 *** that Mo_(3)B_(4) or W_(3)B_(4) are not stable phase,20%of M03B4 and W3B4 can be stabilized into the high-entropy M3B4 *** hardness was measured to be 18.6 and 19.8 GPa at a standard load of 9.8 *** work has further expanded the family of different structures of high-entropy ceramics reported to date.
The application of all-solid-state Li-metal batteries with solid oxide electrolytes is hindered by interfacial issues,especially the solid electrolyte/Li-metal *** work introduced a uniform indium film layer on the su...
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The application of all-solid-state Li-metal batteries with solid oxide electrolytes is hindered by interfacial issues,especially the solid electrolyte/Li-metal *** work introduced a uniform indium film layer on the surface of Na^(+)super ionic conductor(NASICON)solid electrolyte Li_(1.5)Al_(0.5)Ge_(1.5)P_(3)O_(12)(LAGP),which promotes the intimate contact between Li metal and solid electrolyte and hinders the side reactions at the *** impedance spectra show that the battery with coated solid electrolyte presents a smaller interfacial resistance and maintains stability after a long cycling *** contrast,the baseline battery with a pure LAGP pellet shows a contact loss after cycling with the vibration of interfacial *** Li symmetric cells with indium-modified solid electrolyte present stable cycling behavior over 400 h at 0.1 and 0.2 mA·cm^(−2).The all-solid-state Li-metal batteries with a Li anode,indium coating LAGP and two kinds of cathodes,namely carbon nanotubes(CNTs)and LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811),are prepared and *** CNTs cathode for Li-O2 and Li-air batteries has a higher specific capacity than traditional Li-ion battery *** Li-NCM811 batteries deliver an initial Coulombic efficiency of about 75%,with 82%capacity retention after 20 cycles.
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