3,567 research outputs found

    Demographic security as a basis of sustainable development of the state

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    SUSTAINABLE ECONOMIC DEVELOPMENT: INTERNATIONAL AND NATIONAL ASPECTS (Novopolotsk, 25 - 26 October 2012) V.2. p.2 Gass, M.V.Секция 5. ТЕОРЕТИЧЕСКИЕ ОСНОВЫ ИССЛЕДОВАНИЯ ФОРМ РАЗВИТИЯ И ФАКТОРОВ РОСТА НАЦИОНАЛЬНОЙ ИННОВАЦИОННОЙ СИСТЕМ

    Labor Law - Unemployment Compensation - Voluntary Termination of Employment

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    The Supreme Court of Pennsylvania held that a claimant who is justifiably demoted and subsequently terminates his employment is not entitled to receive unemployment compensation. Allegheny Valley School v. Pennsylvania Unemployment Compensation Bd., 697 A.2d. 243 (Pa. 1997)

    The microstructure and microtexture of zirconium oxide films studied by transmission electron backscatter diffraction and automated crystal orientation mapping with transmission electron microscopy

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    A detailed characterization of nanostructured thin zirconium oxide films formed during aqueous corrosion of a nuclear-grade zirconium alloy (Zircaloy-4) has been carried out by means of two novel, ultra-high-spatial-resolution grain mapping techniques, namely automated crystal orientation mapping in the transmission electron microscope (TEM) and transmission electron backscatter diffraction (t-EBSD). While the former provided excellent spatial resolution with the ability to identify tetragonal ZrO<sub>2</sub> grains as small as ∼5 nm, the superior angular resolution and unambiguous indexing with t-EBSD enabled verification of the TEM observations. Both techniques revealed that in a stress-free condition (TEM foil prepared by focused ion beam milling), the oxide consists mainly of well-oriented columnar monoclinic grains with a high fraction of transformation twin boundaries, which indicates that the transformation from tetragonal to monoclinic ZrO<sub>2</sub> is a continuous process, and that a significant fraction of the columnar grains transformed from stress-stabilized tetragonal grains with (0 0 1) planes parallel to the metal–oxide interface. The TEM analysis also revealed a small fraction of size-stabilized, equiaxed tetragonal grains throughout the oxide. Those grains were found to show significant misalignment from the expected (0 0 1) growth direction, which explains the limited growth of those grains. The observations are discussed in the context of providing new insights into corrosion mechanisms of zirconium alloys, which is of particular importance for improving service life of fuel assemblies used in water-cooled reactors

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    Compositional analysis of InAs-GaAs-GaSb heterostructures by low-loss electron energy loss spectroscopy

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    As an alternative to Core-Loss Electron Energy Loss Spectroscopy, Low-Loss EELS is suitable for compositional analysis of complex heterostructures, such as the InAs-GaAs-GaSb system, since in this energy range the edges corresponding to these elements are better defined than in Core-Loss. Furthermore, the analysis of the bulk plasmon peak, which is present in this energy range, also provides information about the composition. In this work, compositional information in an InAs-GaAs-GaSb heterostructure has been obtained from Low-Loss EEL spectra

    A Maximum Entropy Method of Obtaining Thermodynamic Properties from Quantum Monte Carlo Simulations

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    We describe a novel method to obtain thermodynamic properties of quantum systems using Baysian Inference -- Maximum Entropy techniques. The method is applicable to energy values sampled at a discrete set of temperatures from Quantum Monte Carlo Simulations. The internal energy and the specific heat of the system are easily obtained as are errorbars on these quantities. The entropy and the free energy are also obtainable. No assumptions as to the specific functional form of the energy are made. The use of a priori information, such as a sum rule on the entropy, is built into the method. As a non-trivial example of the method, we obtain the specific heat of the three-dimensional Periodic Anderson Model.Comment: 8 pages, 3 figure

    A note on a third order curvature invariant in static spacetimes

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    We consider here the third order curvature invariant I=Rμνρσ;δRμνρσ;δI=R_{\mu\nu\rho\sigma;\delta}R^{\mu\nu\rho\sigma;\delta} in static spacetimes M=R×Σ{\cal M}=R\times\Sigma for which Σ\Sigma is conformally flat. We evaluate explicitly the invariant for the NN-dimensional Majumdar-Papapetrou multi black-holes solution, confirming that II does indeed vanish on the event horizons of such black-holes. Our calculations show, however, that solely the vanishing of II is not sufficient to locate an event horizon in non-spherically symmetric spacetimes. We discuss also some tidal effects associated to the invariant II.Comment: 5 pages, 3 figures. Extra material available at http://vigo.ime.unicamp.br/in

    A study into the impact of interface roughness development on mechanical degradation of oxides formed on zirconium alloys

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    AbstractAs a cladding material used to encapsulate nuclear fuel pellets, zirconium alloys are the primary barrier separating the fuel and a pressurised steam or lithiated water environment. Degradation mechanisms such as oxidation can be the limiting factor in the life-time of the fuel assembly. Key to controlling oxidation, and therefore allowing increased burn-up of fuel, is the development of a mechanistic understanding of the corrosion process. In an autoclave, the oxidation kinetics for zirconium alloys are typically cyclical, with periods of accelerated kinetics being observed in steps of ∼2μm oxide growth. These periods of accelerated oxidation are immediately preceded by the development of a layer of lateral cracks near the metal-oxide interface, which may be associated with the development of interface roughness. The present work uses scanning electron microscopy to carry out a statistical analysis of changes in the metal-oxide interface roughness between three different alloys at different stages of autoclave oxidation. The first two alloys are Zircaloy-4 and ZIRLO™ for which analysis is carried out at stages before, during and after first transition. The third alloy is an experimental low tin alloy, which under the same oxidation conditions and during the same time period does not appear to go through transition. Assessment of the metal-oxide interface roughness is primarily carried out based on the root mean square of the interface slope known as the Rdq parameter. Results show clear trends with relation to transition points in the corrosion kinetics. Discussion is given to how this relates to the existing mechanistic understanding of the corrosion process, and the components required for possible future modelling approaches
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