The present work is aimed at the determination of the thermal expansion of oxides of yttrium, cerium, and praseodymium as a function of temperature (300–1000 K). The values of thermal expansion have been determined from linear attenuation coefficient of gamma rays and density in the range 300–1000 K. Measurements on the attenuation of gamma rays have been made with an experimental set up assembled in our laboratory, using the radioactive gamma source 137Cs(0.662 MeV). The results on the linear gamma ray attenuation µl, density ρ, and the coefficient of linear thermal expansion α of yttrium oxide (Y2O3), cerium oxide (CeO2), and praseodymium oxide (Pr6O11) as a function of temperature have been fit to a second degree polynomial equation. The present results on the thermal expansion of Y2O3, CeO2, and Pr6O11 have been compared with the results obtained from X-ray diffractometry and interferometry methods.

The effect of low-intensity forced oscillations of a gas on the temperature field in a rectangular channel is studied. A nonuniform temperature distribution along the side wall of the channel during resonance was revealed. The maximum heating of the gas is observed near the piston and the closed end, which is due to the work of compression forces in the pressure antinodes at the ends of the channel, which form in a standing wave. An increase in the average temperature in the channel with increasing duration of experiment in the resonance mode of gas oscillations was revealed.

The composition and properties of the gas-like products of the destruction of heat-shielding materials are an important characteristic of the thermal protection of high-temperature installations, especially solid-propellant rocket engines. Based on the analysis of the well-known experimental data on the composition of polymer pyrolysis products, the experimental results obtained for a characteristic heat-shielding rubber-like material and the calculated estimates using the known thermodynamic calculation programs, the characteristic features of the qualitative and quantitative compositions of gas-like products of the thermal destruction of rubber-like thermal protection are determined.

The results of experimental studies of the electric discharge of alternating current (f = 50 Hz) in a gas–liquid environment of an electrolyte with bubbles for interelectrode distances of 50–150 mm inside a dielectric tube are presented. The presence of a bubble structure with microdischarges affects the nature of the discharge current and voltage ripples. The frequency spectrum of voltage and current oscillations of the discharge is established using the fast Fourier transform. Based on the analysis of the experimental data, the mechanism for the development of an alternating current electric discharge in a medium with microbubbles is established.

The thermal distortion temperature, which determines the upper temperature limit of thermal stability of polymer materials, is analyzed using polyamide-6/organoclay nanocomposites as an example. It is shown that an increase in this temperature is determined by the total content of close-packed regions of the nanocomposite–nanofiller and interfacial regions. It is determined that the degree of anisotropy of a nanofiller in a polymer matrix significantly affects the thermal stability of nanocomposites. The proposed theoretical model makes it possible to predict the thermal distortion temperature of the studied nanocomposites as a function of the nanofiller content and degree of its anisotropy with quite high accuracy.

The article describes the statistical algorithms for calculating scattered radiation by the Monte Carlo method. Emphasis is on calculating light scattering in a medium with distributed volumetric radiation sources, for which an object was chosen in the form of an axisymmetric gas volume simulating an aircraft engine jet with nonuniform temperature and concentration distributions of the scattering particles. The theory of three Monte Carlo algorithms and their implementation on a graphics processor are demonstrated: the direct method of tracking photon trajectories and methods based on expansion in a Neumann series of solutions to the direct and adjoint radiative transfer equations (local estimates), taking into account weight modifications and various scattering indicatrices. Visual comparison of the operation of the algorithms is facilitated by presenting the data as the functional of the radiation rate and the area of the radiating surface (radiant intensity).

The article studies heat transfer in a semi-infinite straight line with thermal conductivity depending exponentially on temperature. The introduction of a self-similar substitution reduces the heat conduction problem to a nonlinear ordinary differential equation. Its solution showed the wave nature of heat emission in the form of traveling heat waves. The solution gives a limiting time beyond which the heat flux is “locked” at some distance from the boundary of the body, despite the fact that the temperature or heat flux at the boundary can increase indefinitely. The limiting heating depth above which the computational domain remains cold (with the initial temperature) is determined.

The article considers the main provisions of three versions of perturbation theory: BH (D. Henderson and J.A. Barker), WCA (J.D. Weeks, D. Chandler, and H.C. Andersen), and KLRR (H.S. Kang, C.S. Lee, T. Ree, and F.H. Ree) used to calculate the thermodynamic properties of binary mixtures of dense gases in a wide range of pressures and temperatures. The interaction of molecules is described using the spherically symmetric pair potential exp-6. Verification was carried out by comparing experimental data on the compression of binary helium–hydrogen and ammonia–hydrogen mixtures, as well as on shock-wave compression of liquid N2, O2 with the results of equilibrium thermodynamic calculations and Monte Carlo simulations. It is shown that for thermodynamic simulation of the properties of binary mixtures, the most accurate version of perturbation theory is the modernized KLRR-T theory.

The paper presents a fundamentally new design for a hydrogen generator. Hydrogen is released during the reaction of activated aluminum and water. Bismuth, tin, and calcium oxide were used as the activating additives. The hydrogen generator results in an Al oxidation reaction at a temperature of 100–350°C and a pressure of about 4 atm. An average hydrogen production rate of 30 mL/(s g) was achieved with a hydrogen yield of 95–99% of the theoretically possible value. In continuous generation mode, the average productivity of the hydrogen generator was ~1.5 kW (140 mL H2/s).

Within the framework of the thermodynamics of a two-phase system with a curved surface, an equation is obtained for the size dependence of the surface tension of a spherical particle at the boundary with vapor, taking the effect of phase equilibrium on the temperature into account. Numerical calculations have been carried out for liquid nanodroplets of a number of metals. A nonmonotonic change in the surface tension with a decrease in the radius of the tension surface has been established: an increase in the region of large sizes and a decrease in the region of small ones.