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This work presents studies of the electrocatalytic properties of ternary CoWRe alloys during the hydrogen-evolution reaction in KOH solution and their corrosion properties in KOH, H2SO4 and NaCl solutions. These alloys are electrodeposited from a citrate-pyrophosphate electrolyte with potassium-perrhenate concentrations of 0.01, 0.03, and 0.05 mol⋅l−1 . As shown, the use of such alloys makes it possible to increase the exchange current density by an order of magnitude and reduce the hydrogen overvoltage by 150 mV compared to electrolytic cobalt. An increase in the content of rhenium in the alloy leads to an increase in the overvoltage of hydrogen evolution in alkaline solutions: both in the KOH solution and in the electrolyte for the deposition of the alloy that explains the high current efficiency when obtaining alloys’ coatings. As shown, the highest corrosion resistance of such coatings with the ratio Re:W = 2:4 reaches 8.9 kΩ⋅cm² in NaCl solution, and in KOH solution, it is of 3.1 kΩ⋅cm², and corrosion resistance increases in time. [ABSTRACT FROM AUTHOR]

The stress-strain state of the foundations of buildings and structures made of weak viscoelastic soils is considered. The mechanical characteristics of a viscoelastic water-saturated soil base were determined experimentally. A macro sample of soil in a pipe about 1 m high had a water lock on top to create excess pore pressure in the sample. Excessive pore pressure simulated the depth of the sample from the surface. From the experiment, the universal parameter of the kinematic model was determined, and the foundation was calculated. Theoretical data obtained within the framework of a kinematic model considering the viscoelastic properties of the soil are compared with the known Flamant solution and experimental data for a stabilized state of the soil. The deviation of vertical displacements from experimental data is no more than 4 % (one-dimensional case). The deviation of the theoretical solution of the flat Flamant-type problem (considering residual pore pressures) from the known solution of the Flamant problem is 16 %. The proposed calculation method makes it possible to predict the deformation of foundations made of water-saturated viscoelastic soils more accurately than the solution for elastic and elastoplastic soils without the influence of pore pressure. The technique is novel because it allows one to simultaneously consider the soil's residual pore pressures and the soil's viscoelasticity.

The object of the study is frame-gantry pile foundations embedded in the soil base. To improve the strength of weak soil base, various methods of reinforcement are used, including the foundation constructions in the form of wedge-shaped piles. The paper deals with laboratory studies of the soil base during the installation of small-scale wedge-shaped piles at different angle. The process of soil shearing under the influence of the loads is registered by deformation control benchmarks arranged in the form of a square grid. The interaction between the soil and the frame-gantry foundations appears in a change of the physical and mechanical characteristics in the near pile area. The tests revealed that when piles are installed at the angle of 30° the bearing capacity of the foundation increased. The average density in the fixed active zone of the soil area increased by 12 %, and the average porosity coefficient decreased by 20 %. The deformation modulus changed by 1.8–2.3 times. The angle of internal friction remained virtually unchanged.

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The paper presents the study results of the various recipes of production trout mixed fodders produced by LLC "RybProm" on the condition of rainbow trout (Oncorhynchus mykiss Walbaum, 1792) during its cultivation in cages in comparison with the feed produced by Coppens. The physiological condition of the studied fish was evaluated, haematological, biochemical studies and pathological and anatomical autopsy were carried out. It was shown that the feed coefficient in the control group was 1.2, and in the experimental feeds from 1.3 to 1.5. Of the three studied feeds, the feed "Recipe #3" is practically not inferior in feed coefficient and growth rate to the control group. The conducted researches at the cage trout farm showed that the feeds of domestic production correspond to imported analogues. All studied feed recipes are safe for the health of rainbow trout and are sufficiently balanced for its cultivation in cages.

The article discusses feed additives with probiotic activity, the composition and methods of their preparation, an assessment of the situation of the use of synbiotic additives in compound feeds. Generalised literature data on the use of synbiotics in animal husbandry and aquaculture are presented, their advantages and disadvantages are revealed. A review of studies on the use of feed with probiotic activity in the diet of animals, birds and fish proves the high effectiveness of their use: there is an increase in survival, a decrease in feed conversion, an improvement in the microbiota and the general condition of the animal. Based on the review, a new substrate for growing bacterial strains based on a grain heap of wheat in the early stages of ripeness is proposed.

Ensuring a well-organised and sustainable feed base is the main condition for the development of animal husbandry, increasing its productivity and product quality. To ensure active growth and high productivity, probiotic feed additives are added to the feed, which increase the immune response of the host organism to pathogenic microorganisms, increases the conversion of feed and live weight gain. One of the main processes of feed production is extrusion, which can be cold, warm and hot. The hot extrusion process takes place at a temperature above 130℃ and cannot be used in the production of compound feeds with probiotics that withstand temperatures up to 85℃. During cold extrusion, the temperature reaches no higher than 70℃, which allows the extrusion of mixed feed mass, which contains probiotic feed additives.

The use of insects as raw materials for the production of feed additives is becoming an increasingly relevant and promising area of research. Nevertheless, this area requires numerous studies, including theoretical ones. The article presents the results of research on mathematical modeling of the process of obtaining feed additives in the form of fat and protein from the larva of the Black soldier fly (Hermetia illucens) in a screw press. Mathematical models have been obtained that allow theoretically determining the productivity of a screw press and its energy intensity in the processing of insect biomass. The models are based on the Navier–Stokes equation and Darcy’s law and take into account the design and kinematic parameters of the screw press and the rheological properties of the biomass of the face and the resulting fat.

The shortage of fish meal and fish oil provokes the search for alternative sources of these feed components. Insects that are part of the diet of animals, birds and fish, rich in protein and fat, can serve as such an alternative. The article presents the results of testing of compound feed for fish containing the fat of the larvae of the black soldier fly (Hermetia illucens) and a feed additive with probiotic activity. The use of the fat of the larva of the black soldier fly (Hermetia illucens) and a probiotic feed additive allows increasing the survival rate of fish from 90 to 95%, increase the conversion of feed and the average daily increase. The calculation of the economic efficiency from the use of compound feed, which includes feed additives of animal origin and additives with probiotic activity, showed an increase in profit when replacing compound feed made according to a standard recipe with compound feed with new feed additives. The economic effect of using compound feed with new feed additives amounted to more than 650 thousand rubles per year on small and medium-sized trout farms up to 20 tons per year.

The production of quality and inexpensive feed based on agricultural raw materials is the main way to increase the profitability and competitiveness of livestock production, ensuring its import substitution and high quality. It is known that in the structure of the cost of livestock products, 50-70% of all costs are accounted for by feed. Three variants of a mixture of crushed wheat grain and biomass of the black soldier fly larvae (Hermetia illucens) were extruded with the content of the latter 10, 15, and 20% by weight at different temperatures. The content of amino acids in raw materials and finished extrudate was determined. It was found that the feed mixture of crushed grain and black soldier fly larvae can be successfully extruded at a temperature of 121-135 °C. With an increase in the extrusion temperature in the range of 115-140 °C, the amino acid content in the finished extrudate decreases. The change in the content of insect larvae in the feed mixture does not affect the nature of the dependence of the amino acid content in the extrudate on the extrusion temperature and the course of the process. It was found that the content of amino acids in the extruded feed decreases with increasing speed with increasing temperature, regardless of the content of insect biomass. The rational range of the extrusion temperature of the feed mixture from wheat grain and insect larvae was determined – 121-127 °C, which ensures a reduction in the content of essential amino acids in the extrudate by no more than 30%. The extruded feed, which includes 15% of the biomass of insect larvae, contains 9.6 ± 0.13% amino acids, including 4.38 ± 2.01% of essential amino acids. The extrusion of insect larvae in a mixture with seeds of grain crops is a promising direction for improving the production of feed for fish and farm animals.