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The three-dimensional structure of the flow in the near field of a wake behind a cylinder in a slot channel was experimentally investigated. Based on direct measurements of three-component volumetric velocity distributions, the ave-raged flow structure in a wake behind the cylinder is presented for the cylinder height-to-diameter ratio of 0.4 and Reynolds number Re _D = 3500. It is shown that the horseshoe vortices formed in front of the cylinder affect the flow structure significantly. It is found that two quadrupole distributions of mean longitudinal vorticity are formed in the near wake.

Various studies have shown that a baffle installation can enhance heat transfer in the backward facing step flows. It increases the pressure drop in the channel. In this study, the main focus is to find the best installation location and orientation for a given baffle to maximize its thermal performance. A steady incompressible laminar flow is considered in a channel with an expansion ratio of 2. The bottom wall of the channel is partially heated with a constant heat flux. For numerical modeling, the Navier-Stokes equations were solved using the finite element method. Two new concepts entitled the maximum temperature constraint and the performance evaluation parameter (PEP) were defined to characterize the problem. Grid independence study was performed, and the numerical simulation was validated successfully with the published results. As the main result, a small zone close to the step was identified for the baffle installation which gives higher values of the PEP and constrained PEP. It was shown that under the present circumstances, the case ( X _b, Y _b, a ) = (0.3, 0.9, -15°) gives the highest heat transfer enhancement (75 %) and the case ( X _b, Y _b, a ) = (0.3, 0.9, 30°) is the most optimum case from the thermal performance point of view with constrained PEP which is of 1.257.

The article presents the results of studies of a coolant flow behind the mixing intensifier grids of TVS Kvadrat fuel assemblies of the PWR. The purpose of the work is to evaluate the efficiency of mixing the coolant behind the intensifier grids of various designs and to choose their optimal design. To achieve this goal, a number of experiments are carried out on the aerodynamic research stand with scale models of fuel rod bundle fragments of fuel assemblies with mixing intensifier grids, equipped with turbulizing deflectors of various profile shapes. The cells located near the guide channel and regular cells are selected as the research area. The choice of the research area is due not only to the need to obtain a hydrodynamic picture of the coolant flow in characteristic cells and the choice of the optimal shape of the deflector, but also due to the necessary assessment of the influence of transverse coolant flows from the area of the guide channel on the flow motion in adjacent cells. The coolant flow pattern is represented by vector fields of transverse velocities, cartograms of the distribution of transverse and axial velocities, as well as graphical dependences of the distribution of the flow velocity components. Analysis of the spatial distribution of transverse and axial flow velocities allows studying and detailing the flow pattern of the coolant. Evaluation of the efficiency of the coolant mixing behind the grids and determination of the optimal shape of the deflector profile are carried out on the basis of a comprehensive analysis of the hydrodynamic pattern of the coolant flow and the parameters of intracellular vortex formation and intercellular mixing. The experimental results can be used in the engineering justification of structural solutions for the design of active zones of PWR reactors with TVS-Kvadrat. The accumulated database of experimental data is used for verification of CFD programs (both foreign and domestic development), as well as programs for thermal-hydraulic cell-by-cell calculation of active zones.

Two wind tunnels were employed for study of a thick teardrop airfoil with the relative thickness of 40 %. Experiments were conducted for Reynolds number in the range from 2 10⁴ to 12 10⁴ and the angle of attack from -10° to +10°. The weight-in-flow measurements and PIV-method visualization were performed. Experiments revealed a strong impact of the free-stream pulsations on the aerodynamic force coefficients. The following phenomena were demonstrated: drag crisis, hysteresis for the lift force vs. angle of attack, and reversing for the lift force direction. Data analysis investigates the roots of these effects.

The influence of the Pitot probe on total pressure measurements in the near-wall flow in the zone of reattachment of a supersonic separated flow past a compression corner is considered. If the total pressure is measured near the model wall, a local maximum is observed in the region downstream of the reattachment line. This maximum can be either a physical structural element of the separated flow (high-pressure layer in which the total pressure reaches 0.8-0.95 of the free-stream total pressure) or a possible measurement error. The present study reveals the existence of a measured total pressure peak in the boundary layer on a horizontal flat plate and flat wedges. This peak is not associated with the high-pressure flow, but is rather a result of probe interaction with the model wall. The amplitude of this peak is found to depend on the ratio of the probe size and the boundary layer thickness. It is shown that the degree of the probe influence leading to distortion of the measurement results is smaller approximately by an order of magnitude than the maximum value of the measured total pressure in the high-pressure layer in the reattachment zone.

Results of numerical simulations of a supersonic (М_¥ = 7) flow around a cylinder with a gas-permeable frontal insert made of a high-porosity cellular material are reported. A toroidal skeleton model of a high-porosity medium is developed and implemented to describe air filtration in the gas-permeable insert. The aerodynamic coefficients of the cylinder model for various angles of attack ( a = 0¸15°) are obtained. They are found to agree well with available experimental data, which confirms that the proposed skeleton model adequately describes the real properties of high-porosity materials.

An overview of the research carried out at the Boreskov Institute of Catalysis SB RAS on the application of catalytic technologies to develop energy-efficient designs of high-temperature fuel cell (FC) batteries is provided. The catalysts for high-temperature combustion of methane and catalytic burners for efficient fuel combustion in the reformers of installations operating on fuel cells were developed. Internal reformers with active and durable catalytic coatings have been developed, allowing the formation of synthesis gas directly inside the battery of high-temperature molten carbonate and solid oxide FC, providing a compact and energy-efficient design of power plants.

A review of scientific publications and the results of experiments in the area of synthesis and investigation of the biological activity of functionally substituted norbornene derivatives is presented. The high antibacterial, antifungal and antiseptic activity of different derivatives of bicyclo[2.2.1]-heptene was demonstrated, which is explained by the presence of a pharmacophore conformational rigid framework of the norbornene fragment, as well as its saturated analogue. The synthesis of norbornene-containing Mannich bases was carried out through a one-pot three-component aminomethylation participated by norbornenylmethanol, formaldehyde and secondary amines. It is stressed that norbornenylmethanol, synthesized previously on the basis of a diene synthesis reaction between cyclopentadiene and allyl alcohol, was first used as an alcohol component in the Mannich reaction. The synthesized norbornene-containing Mannich bases were tested for antimicrobial and antifungal activity against various microorganisms. It was established that the synthesized compounds exhibit high antimicrobial activity against gram-positive ( Staphylococcus aureus ), gram-negative ( Escherichia coli , Pseudomonas aeruginosa ) bacteria, and antifungal activity against the fungi of Candida genus. The minimum inhibitory and minimum bactericidal concentrations of these compounds against some of the above-listed microorganisms were determined. Comparative characteristics of the antimicrobial and antifungal properties of the synthesized norbornene-containing Mannich bases with respect to well-known reference drugs widely used in medical practice (carbolic acid, rivanol, furacilin, chloramine) were determined. It was shown that the synthesized compounds possess higher biological activity than the reference preparations.

The results of the studies aimed at the improvement of the mode of flotation of flocculated coal due to the application of Sinterol, a new modifying reagent, are reported. Coals from the basins of the Russian Federation with different degrees of organic mass mineralization were used as the initial coal samples. When applying the modifying reagent Sinterol in the amount of (1-3) · 10^-3 kg/t and simultaneously reducing the total consumption of reagents by 13.0 % on average (from 3.000 to 2.613 kg/t), the concentrate yield increased by 2.5-8.5 %, the ash content of the concentrate decreased by 2.7-3.0 % the extraction of combustible mass into the concentrate increased by 2.9-7.1 %. The ash content of the waste increased by 2.9-12.3 % and was in the range of 72.6-82.0 %. A decrease in the ash content of the concentrate and an increase in the ash content of the waste with an increase in the modifying reagent input are explained by the flocculating effect of the reagent on the mineral particles of the pulp, which is important for flotation of hard-to-enrich coal fines containing a large amount of clay substances. The efficiency of the Sinterol flocculant reagent at its low consumption was revealed. The reason is the prevailing enlargement of the particles of mineral impurities and a decrease in their floatability together with the organic mass of coals.

The shallows of the Laptev and East Siberian seas formed on the site of islands composed of the sediments of the Late Pleistocene Ice Complex which eroded in the 17th–20th centuries and are linked to positive morphostructures. The present article considers factors of modern sedimentation in marine shallows with the formation of islands (Yaya, Nanosny, Zatoplyaemyy, Leykina, etc.). Among these factors are a decrease in sea ice extent, an increase in the duration of the ice-free period, and the activation of destructive cryogenic processes triggered by the current climate warming. A decrease in ice coverage led to the dominance of hydrodynamic processes in sedimentation, unlike the primary role of sea ice in this process in the 17th–19th centuries. Sediment deficit in these centuries is substituted by its excess owing to the activation of cryogenic processes at the turn of the 20th and 21st centuries. As a result, the erosional profile of underwater slopes of shallows is transforming into an accumulative one. Sedimentation is occurring parallel to a rising sea level related to a warming climate. A rise in the surface of islands and sandbanks is recorded on satellite images where there are modern positive vertical movements. The formation of islands and sandbanks is accompanied by their syngenetic freezing.