Study of the Effects of Thermomechanical Coupling Near Stress Concentrators in Viscoelastoplastic Bodies

A model is developed to investigate thermal effects in elastoviscoplastic bodies. It allows us to obtain some quantitative and qualitative information on the stress–strain state of a body and to carry out a nondestructive diagnostics of internal defects, which are stress and strain concentrators. The problem on the plane stress state of a rectangle with a hole is considered as an example. The plate is made of steel and aluminum alloy. The variation in the temperature on the external contour of the body under monotonous and cyclic tension in the elastic and plastic domains is studied     

Thermomechanical Coupling Effects Near Defects in Inelastic Bodies

Models used to study thermal effects in elastoviscoplastic and viscoelastic bodies deformed under monotonic and harmonic loading are considered. They allow us to obtain qualitative and quantitative information on the thermomechanical state of the material. Numerical results can be used in a nondestructive analysis and in predicting thermal fatigue failure of inelastic bodies     

Measuring deuteron beam parameters with solid-state track detectors in experiments with the QUINTA target assembly

The results of measurements of the beam parameters on the target upon irradiation of the QUINTA subcritical uranium assembly with deuterons with energies of 1, 4, and 8 GeV are presented. Data on the position of the incident particle beam relative to the assembly axis and on the actual geometric parameters of the beam make it possible to analyze information on the spatial distributions of reaction rates within the target assembly correctly, comparing such distributions obtained at different irradiation sessions and modeling the experiments with the use of MCNPX, GEANT4, FLUKA, and other similar software tools.     

Estimates for functionals with a known moment sequence in terms of deviations of Steklov type means

Some estimates for functionals indicated in the title are established. As implications, Jackson type inequalities with constants smaller than the previously known ones are obtained. The results hold in various spaces of both periodic and nonperiodic functions. Bibliography: 9 titles.     

The rate of decrease of constants in Jackson type inequalities in dependence of the order of the continuity modulus

Jackson type inequalities for moduli of continuity of arbitrary order are established with the use of linear approximation methods. The constants are smaller than known previously. The results hold in different spaces of periodic and nonperiodic functions. Bibliography: 19 titles.     

Structural transformations in ZnS:Cu in the course of thermal annealing

The influence of annealing at 800°C on the photoluminescence, electron spin resonance, and X-ray diffraction spectra of powder-like ZnS:Cu, obtained by the self-propagating high-temperature synthesis of a charge, consisting of Zn, S, and CuCl, is studied. It is shown that variation in the material’s heating rate up to the annealing temperature leads to a nonmonotonic variation in the spectral location and full-width at half-maximum of the photoluminescence band in the blue-green spectral region, as well as in the Mn²⁺ paramagnetic center concentration. It is established that the cubic and hexagonal ZnS phases, as well as the ZnO and CuZn phases, are present in the powder after synthesis. It is shown that annealing of the obtained powder at 800°C leads to three processes: the transformation of the hexagonal ZnS phase into the cubic phase, the oxidation of ZnS and CuZn, and the diffusion of Cu into the bulk of the ZnS microcrystals from the CuZn phase. A model attributing the observed variations in luminescence and electron spin resonance spectra to the diffusion of Cu and Mn impurities into the microcrystal bulk, particularly from the CuZn phase, and to their accumulation at extended defects is suggested.