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The paper describes the design of an electron extraction device using differential pumping. An assessment of the vacuum conditions for the transition from the viscous to the molecular regime is considered, which makes it possible to confirm the correctness of the choice of the parameters of the differential pumping system, which makes it possible to confirm the correctness of the choice of the parameters of the differential pumping system. The problem of heat removal from differential pumping diaphragms in a compact all-metal body of the extraction device.

The influence of mechanical processing of CuAl₁₀Fe₃Mn₂ bronze particles with different energy input intensities on the process of deposition of coatings by the method of cold gas-dynamic spraying and the properties of these coatings is studied. It is shown that the deposition efficiency varies depending on the microhardness and porosity of deposited particles. The increase in the porosity (from 2 to 8%) of the resultant coatings for different regimes and intensities of mechanical processing of deposited particles is explained. It is found that the size of the coherent scattering region, material microhardness, and roughness of coatings obtained from the mechanically treated powder have similar values regardless of the intensity of energy input by milling bodies to the processed material.

The vibration levels of a metal plate are measured in the absence and presence of either one reinforced coating on its surface or one reinforce coating (or two of them) with the same or different thickness placed on it. The effectiveness of various schemes for lining the plate with coatings is determined and compared.

An effective method and fast modeling in vibration and flutter analyses of low-aspect-ratio composite wings and wings with a control surface in a subsonic flow are proposed. An equivalent plate method is used for structural modeling. The doublet point and the U - g methods are applied to calculate unsteady aerodynamic loads and flutter analysis, respectively. The obtained results are in good agreement with the literature data.

This paper considers the problem of purified turbulent flow over an erodible bed. A mathematical model of the problem is proposed which includes the Reynolds equations and transport equations for turbulent kinetic energy and turbulence dissipation. The bed surface evolution is described using the bed deformation equation and the original analytical model of bed-load sediment transport. An algorithm based on the control volume method is proposed for solving the problem. Numerical solution of the problem shows that when the bed is eroded by a purified flow, a wave packet of low-steepness bed waves is formed. It is also shown that the velocity of bed waves obtained by the numerical solution is in good agreement with the velocity of bed waves calculated by asymptotic analytical formula.

An experimental stand has been developed to study oil recovery using supercritical fluid systems of bulk and composite homogeneous porous materials in the mode of miscible and microbubble filtration of a mixture of oil and supercritical carbon dioxide. A device for visualizing the emergence of supercritical CO₂ microbubbles from the experimental cell with a porous medium has been designed. The oil recovery by supercritical CO₂ and rims of supercritical CO₂ and water from a homogeneous bulk porous medium has been experimentally studied. It has been shown that the miscible mode of viscous oil recovery by supercritical CO₂ is most efficient and the efficiency of viscous oil recovery in the microbubble mode can be increased using rims of supercritical CO₂ and water. The mechanism of oil recovery enhancement in the region of microbubble recovery of viscous oil by supercritical CO₂ is described.

We study the problem of three-dimensional stationary creeping flow of two immiscible liquids in a channel with solid parallel walls, one of which a given temperature distribution is maintained and the other is hear-insulated. Thermocapillary forces act on the flat interface. Temperature in the liquids depends quadratically on the horizontal coordinates, and the velocity field has a special form. The resulting conjugate problem for the Oberbeck- Boussinesq model is inverse and reduces to the system of ten integro-differential equations. The total energy condition is taken into account on the interface. The problem has up to two solutions and if the heat fluxes are equal, then it has one solution. Characteristic flow structures are constructed for each of the solutions. The influence of dimensionless physical and geometric parameters on the flows is investigated

A mathematical model of stepwise natural gas pressure reduction in a multistage turboexpander has been developed using a thermodynamic approach taking into account the real gas properties. It has been shown that the maximum use of natural gas overpressure energy is provided when the outlet-to-inlet pressure ratio is above the critical value at each stage. The change in the temperature of the natural gas and its technical work at each stage of the turboexpander have been numerically determined. It has been found that the rate of temperature drop and the increment in the technical work of natural gas increase from stages to stage of the turboexpander. Comparison of the calculated and experimental values of the performance parameters of the gas turboexpanders showsthat they are in good agreement.

A dual variational form of a mathematical model of the steady process of heat conduction in a rotating disk of a unipolar direct-current generator is constructed. The model contains two alternative functionals that have coinciding stationary points at which these functionals reach the same extreme values (minimum and maximum if the desired temperature distribution in the disk is unique). This property of the functionals makes it possible to estimate the error of the approximate solution of the considered nonlinear heat conduction problem and control its convergence. The features of the radial temperature distribution in the disk are revealed, and the influence of thermal conductivity and electrical resistivity of the disk material (both dependent on temperature) on this distribution is established. The limiting value of the temperature coefficient of electrical resistivity is determined, at which a steady temperature distribution in a disk of a hyperbolic profile is impossible.

A coupled fracture model is proposed and implemented to investigate the deformation and fracture of elastoplastic materials. The fracture model parameters are determined by constructing true fracture strain diagrams and determining the limiting characteristics of 12Kh18N10T and 10KhSND steel. Numerical simulation results for the fracture of cylindrical rods under tension are presented. It is revealed that the type and nature of tensile fracture of cylindrical samples determined in the calculations are in good agreement with the experimental data.