First Principles Calculation of Elastic Properties of Solid Argon at High Pressures

The density and the elastic stiffness coefficients of fcc solid argon at high pressures from 1 GPa up to 80 GPa are computed by first-principles pseudopotential method with plane-wave basis set and the generalized gradient approximation (GGA). The result is in good agreement with the experimental result recently obtained with the Brillouin spectroscopy by Shimizu et al. [Phys. Rev. Lett. 86, 4568 (2001)]. The Cauchy condition was found to be strongly violated as in the experimental result, indicating large contribution from non-central many-body force. The present result has made it clear that the standard density functional method with periodic boundary conditions can be successfully applied for calculating elastic properties of rare gas solids at high pressures in contrast to those at low pressures where dispersion forces are important.Comment: 4 pages, 5 figures, submitted to PR

Thermocouple Junctioned with Ferrites

Measurements are reported of the thermo-e.m.f. of a thermoelectric junction composed of polycrystalline ferrites or multilayered ferrite films as a function of the temperature. The thermo-e.m.f. of the bulk and ferrite films was much larger than that of the conventional thermoelectric junction made of metals. A positive or negative thermoelectric power was observed depending on the difference in the combination of ferrites. The temperature dependence was almost linear from room temperature up to about 500°C and above which it showed a tendency to saturate. Application of a magnetic field had a reducing effect upon the thermo-e.m.f. at temperature of room to the Curie temperature

Synthesis of Dye-Labeled Poly(vinyl acetate-co-ethylene) (EVA) Latex and Polymer Diffusion in their Latex Films

We describe the synthesis of dye-labeled poly(vinyl acetate-co-ethylene) (EVA) latexes with the purpose of understanding the polymer diffusion behavior in their latex films. Polymer diffusion was followed with experiments based upon fluorescence resonance energy transfer (ET). Both the batch and semibatch emulsion polymerizations of vinyl acetate-ethylene (VAc-E) were examined. The ethylene content of these EVA samples was designed at ∼20 wt% (50 mol%). Under batch emulsion polymerization conditions, the reaction is characterized by a rapid monomer conversion and an increment of E content with reaction time. VAc-E batch emulsion polymerization in the presence of the donor dye 9-phenanthryl methyl methacrylate produced EVA with non-random dye distribution, which makes these samples unsuitable for ET experiments. The semibatch emulsion polymerization of VAc-E was carried out under VAc-starved feeding conditions. The resulting EVA was characterized by constant chemical composition throughout the feed. In addition, our data suggest the presence of two components, distinct in molar mass and degree of branching, in these EVA samples. More importantly, these VAc-E polymerizations in the presence of dyes [9-phenanthryl methyl acrylate as the donor and 2′-acryloxy-4′-methyl-4-(N,N-dimethylamino)-benzophenone as the acceptor] produced EVA with random dye incorporation, making these samples effective for ET experiments. Unlike the typical polymer diffusion behavior in latex films, characterized by small extents of polymer diffusion in newly dried latex followed by an increase of the extent of diffusion upon annealing, our ET experiments showed that polymer diffusion in these EVA latex films was complete by the time the films were dry. We attribute this striking difference to the low glass transition temperature (T g) of the EVA and to its low effective monomeric friction coefficient at the drying temperature.Fil: Jun, W.U.. University of Toronto; CanadáFil: Tomba, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Jung Kwon, O.H.. University of Toronto; CanadáFil: Winnik, Mitchell A.. University of Toronto; CanadáFil: Farwaha, Rajeev. Vinamul Polymers;Fil: Rademacher, Jude. Ici Paints

Silk Nanofiber-Networked Bio-Triboelectric Generator: Silk Bio-TEG

[No abstract available] © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim303