Thermoelectric properties of a Pb0.2Sn0.8Te solid solution prepared through thermal decomposition of salts

We have studied the thermoelectric properties of microcrystalline samples of the Pb_0.2Sn_0.8Te solid solution prepared by hot-pressing fine powders obtained through the thermal decomposition of lead acetate trihydrate and tin oxalate in the presence of tellurium powder. The electrical conductivity, Seebeck coefficient, and thermal conductivity of the samples have been measured at room temperature and in the temperature range 300–700 K and correlated with the particle size of the powders and heat-treatment conditions. We have compared the thermoelectric properties of hot-pressed samples from powders prepared through the thermal decomposition of salts and by mechanical grinding of ingots.     

Carbon foam derived from pitches modified with mineral acids by a low pressure foaming process

Carbon foams with an anisotropic texture and high mechanical strength were produced using precursors obtained after thermo-oxidation treatment of commercial coal-tar pitch with H₂SO₄ and HNO₃. The investigations of the relation between the properties of the precursor and the structure of obtained foam indicate, that the composition and softening point of the pitch precursor significantly affect the foaming process, foam structure and foam mechanical strength. The composition and properties of the modified pitches allow foam formation at relatively low pressure and fast heating rate during the foaming process without a stabilization treatment. The foaming process of pitch-based carbon foams, pre-treatment of the precursors, and the properties of resultant foams are discussed in this paper.     

Heats (enthalpies) of formation of coals and the thermodynamic evaluation of the coal formation process

An approach to the calculation of the quantity of heat consumed in the process of coal formation is presented. The variability of this parameter in a coalification series is analyzed using coals from the Kuznetsk and Tunguska Basins as an example.     

Phase and structural transformations in the aluminum amts alloy upon severe plastic deformation using various techniques

The paper presents experimental data on the structure formation in the commercial aluminum alloy of grade AMts subjected to severe plastic deformation using dynamic channel-angular pressing and torsion under high quasi-hydrodynamic pressure in Bridgman anvils. The dependences of the structural characteristics and hardness on the degree, rate, and scheme of deformation have been analyzed.     

Evolution of the structure of V95 aluminum alloy upon high-pressure torsion

The effect of the degree of deformation upon torsion under quasi-hydrostatic pressure on the structural and phase transformations in the V95 alloy has been studied by the methods of electron microscopy and X-ray diffraction. It has been found that, upon severe plastic deformation, a nanocrystalline structure with a hardness of 2.5 GPa is formed. The nanostructure with a minimum average grain size of 55–80 nm is being formed at e = 5.5–6.4. It has been shown that during dynamical strain aging at e ≥ 4.8, a hardening metastable phase MgZn₂ precipitates from the supersaturated α solid solution, and the quantity of this phase increases with increasing degree of deformation.     

Low-temperature synthesis of the multiferroic compound BiFeO<Subscript>3</Subscript>

A novel, low-temperature process is proposed for the synthesis of the multiferroic compound BiFeO₃. It enables the preparation of nanoparticulate material at temperatures as low as 200–250°C. An important role in the low-temperature synthesis of bismuth orthoferrite is played by ammonium nitrate additions and excess bismuth oxide.     

Possible Application of γ-Ray Spectrometers Based on CdZnTe Detectors

New semiconductor -ray detectors based on CdZnTe have been developed in the last few years, and they are now being widely used. Their advantages are small size and possibility of operating without cooling. In the present work, these detectors are used to measure the radiation from spent fuel assemblies in holding ponds and dry storage sites, unirradiated nuclear materials, and radioactive wastes. The results are analyzed and compared with other types of detectors. The possible applications of CdZnTe-type detectors are determined.     

Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water

We present a new hybrid numerical method for computing the transport of a passive pollutant by a flow. The flow is modeled by the Saint-Venant system of shallow water equations and the pollutant propagation is described by a transport equation. The idea behind the new finite-volume-particle (FVP) method is to use different schemes for the flow and the pollution computations: the shallow water equations are numerically integrated using a finite-volume scheme, while the transport equation is solved by a particle method. This way the specific advantages of each scheme are utilized at the right place. This results in a significantly enhanced resolution of the computed solution     

Prediction of hardening of binary iron alloys due to nitriding on the basis of calculation models

Conclusions