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This paper addresses key challenges in the numerical simulation of gas-particle flows relevant to aerodynamics. Results are presented on the flow structure of the dispersed phase and the associated energy flux to a body surface. Particular emphasis is placed on simulating stochastic phenomena, including inter-particle collisions, the scattering of non-spherical particles upon wall rebound, and particle polydispersity, which are characteristic of real flows, but neglected in classical gas-particle flow theory. The collisional gas of particles within the carrier gas is simulated using a kinetic approach coupled with the direct simulation Monte Carlo (DSMC) method. A three-dimensional model for non-spherical particle-wall collision is implemented, and the particle size distribution in the free stream is described by a log-normal law. Using this approach, the dispersed phase flow structure was investigated for high-speed gas-particle flow over a blunt body (specifically, transverse flow around a cylinder). Energy loss distributions upon impact with the surface are calculated for particles of different shapes. The influence of the shielding effect during particle collisions on the energy loss is also examined.

This paper presents a method for predicting the movement of the laminar-turbulent transition front on the side surfaces of spherically blunted circular cones with account for surface roughness effects. The study demonstrates that mass ablation of the composite thermal protection systems on re-entry vehicles induces surface roughness along the flight trajectory. This roughness arises from differential ablation rates between the constituents of the material, such as fillers and binders, reinforcing frame elements, and the carbon matrix.

Non-equilibrium molecular dynamics (NEMD) simulations are performed to investigate the viscosity and rheology of benzene and nanofluids containing carbon nanotubes of two diameters and varying lengths. The results demonstrate that these fluids exhibit pseudoplastic (shear-thinning) behavior with increasing shear rate. Correlations are established for the critical shear rates as a function of nanotube concentration and length. At high shear rates, the viscosity differences between the nanofluids and the base fluid decrease monotonically, irrespective of nanotube length. This is attributed to shear-induced changes in the momentum dissipation mechanisms within the system.

This paper presents combined experimental and numerical results on the interaction of shock waves with highly porous, permeable barriers featuring both homogeneous and inhomogeneous spatial structures. The experiments are conducted in a shock tube for shock Mach numbers ranging within M = 1.2÷1.8. The experimental barriers comprise stacked wire meshes with triangular cells and layers of cellular nickel foam. The numerical simulations are based on the Reynolds-averaged Navier-Stokes (RANS) equations, utilizing a toroidal skeletal model for the porous media. The results demonstrate that minimal shock wave reflection is achieved using graded barriers, which consist of a sequence of mesh layers with progressively decreasing cell size, capped by a layer of fine-pore nickel foam.

This paper presents numerical simulation results for supersonic turbulent airflow in a planar channel with a backward-facing step, incorporating a volumetric heat source that simulates the heat release from chemical reactions. The simulations account for conjugate heat transfer between the flow and copper plates mounted into the channel walls, which act as heat flux sensor elements. The results show that the heat source reduces the flow velocity and causes an upstream shift of the supersonic wave structure. Increasing the source power enlarges the subsonic zone transversely, induced by flow separation at the shock impingement location. A localized subsonic region forms in the flow core, isolated from the near-wall subsonic zone by a narrow supersonic jet, confining the thermal plume to the core flow. A sharp flow restructuring is triggered when the local separation zone merges with the recirculation zone downstream of the backward-facing step, allowing for the gas (warmed up by the heat source) to penetrate the enlarged separation bubble. This narrows the effective flow region, causing a compression wave, rather than an expansion wave, to form at the step edge. Consequently, the core flow temperature decreases while wall heat fluxes increase substantially.

The gas separation process via a membrane-sorption method шs investigated using a hydrogen-helium mixture and silica microspheres. Experimental and numerical modeling of a two-stage membrane-sorption process for hydrogen-helium mixture separation is carried out. The experimental two-stage separation at 22°C demonstrates an increase in the helium volume fraction from 10.5% in the feed to 57.8% after the first stage and 93.3% after the second stage. Evidently, the final helium volume fraction in the enriched stream is primarily influenced by the amount of depleted mixture remaining in the adsorber prior to the desorption cycle.

Survival, possibility and efficiency of using the bacterial strain of Pseudomonas extremorientalis PhS1 in the combined application in different doses with a chemical seed dresser have been studied for the first time in laboratory and field experiments. In has been established in laboratory experiments that seed dresser Oplot does not cause a decrease in the number of bacteria for 24 h. Phytoexamination of the seeds of spring wheat using the filter roll paper method showed a substantial decrease in the total infection of seeds in all variants in comparison with the reference: the application of chemical preparation caused a decrease in germ length and an increase in the amount of roots; the treatment with both the fungicide and bacteria partially eliminated the retarded effect of the pesticide. In the field experiment, the efficiency of pre-sowing seed treatment with the bacteria, chemical dresser and their mixture was determined: the incidence of root rot on plants during the growing season decreased significantly compared to the control, and the fungicide contributed to an increase in the height and dry mass of plants from the middle of vegetation. Application of both bacteria and the dresser promoted the accumulation of nitrogen in the plants; the use of the fungicide alone caused a decrease in the amount of phosphorus. Analysis of crop structure revealed an increase in plant height and ear length, the number of spikelets and grains per ear, biological yield for either 100 or 50 % dose of the application of chemical preparation by 105 and 59 %, respectively. Seed bacterisation promoted improvement of crop structure but to a smaller extent than the complex treatment, and also caused an increase in crop yield by 14 %. Analysis of grain quality showed that all the methods of pre-sowing treatment of spring wheat seeds provided a statistically significant increase of protein, gluten content, and vitreousness.

Promising adsorbents that normalize the content of copper(II) and zinc ions in the human body may be food products that contain pectin or a sufficient amount of fibres. Within the framework of this study, dependences of the value of copper(II) and zinc ion adsorption by the food products of plant origin (potatoes, carrots, radish, pumpkin, cauliflower, broccoli, vegetable marrow, bananas, plums, apples) were analysed (in the range of metal ion molar concentrations 1.25-5 mmol/L) depending on a number of parameters: temperature (20, 100 °C), acidity (pH 2.0, 6.5), adsorption time (20-60 min). It has been found that the value of adsorption of zinc and copper(II) ions by food products is on average 1.2 times larger after heat treatment than without it. However, with an increase in adsorption time (from 20 to 60 min), the amount of ions adsorbed by food products without their preliminary heat treatment increases by a factor of 1.9 on average, while after heat treatment - by a factor of 1.3. With an increase in the acidity of the medium (pH decrease from 6.5 to 2.0), the value of zinc ion adsorption decreases by a factor of 1.9, and copper(II) ions - by a factor of 1.2 on average. To determine the dependence of adsorption value on time and on concentration of metal ions, several regression models were statistically constructed: linear, quadratic, cubic, power, logarithmic, hyperbolic, common exponential, and natural exponential. Based on the comparison of regression models by correlation and average approximation error, the dependences providing the best proximate description of zinc ion adsorption at the studied parameters have been chosen. These dependences can be used to calculate the necessary amounts of legumes and fruits to correct nutrition for the purpose of bringing zinc ion content in human organism to the normal level.

MgFeGa-layered triple hydroxides (MgFeGa-LTH) were synthesized by co-precipitation method. On the basis of molded polyurethane (PU), the composites (PU)/MgFeGa-LTH were prepared, the effect of particle size of MgFeGa-LTH on flame retardancy and mechanical characteristics of composites was investigated. It has been determined that the introduction of MgFeGa-LTH particles 3.5 μm in size results in a more substantial improvement of fireproof and mechanical characteristics of the composites than the introduction of particles 0.06 μm in size.

The properties of hymatomelanic acids extracted with lower alcohols (methanol, ethanol, n-propanol) from native (unmodified) and ethoxylated humic acids were studied. Humic and hymatomelanic acids were characterized by IR and UV spectroscopy, and the aqueous solutions of their sodium salts were characterized by acid-base potentiometric titration, tensiometry, and dilatational rheology. It has been established that lower alcohols facilitate the extraction of native and ethoxylated hymatomelanic acids, which differ in structure and properties. Ethoxylation products have been found in hymatomelanic acids and in the residues of humic compounds after alcohol extraction. The aqueous solutions of sodium salts of humic, hymatomelanic acids and their ethoxylated forms exhibit pronounced surface-active properties at the interface with air.