The paper presents the results of experimental studies of the features of the operation of prestressed shells, taking into account the various structural parameters of the prestress. It is established that when the winding angle changes from perpendicular to the shell axis to 75° and 65°, the circumferential stresses decrease 1.4 times and 1.2 times, respectively, and the axial stresses increase five and three times, which are two and four times lower than the circumferential, from which it can be concluded that the reduction in the winding angle to the longitudinal the axis of the shell has a positive effect on the stress state of the structure. The study also found that with an increase in the diameter of the winding wire from 1 to 2 mm and a change in the winding angle, the same nature of the stress distribution is observed, but the values of the stress state parameter change, so the efficiency increases up to 25% due to an increase in the winding thickness, depending on the pitch, angle and thickness of the winding, which favorably affects the strength and the bearing capacity of the structure as a whole by increasing the value of the stress state parameter. Thus, the results of the analysis will allow us to use in more detail the possibility of controlling the stress–strain state of the prestressed shell by changing the design parameters, and the results obtained can be used in design or construction, as well as when increasing the strength characteristics of the structure, which allows us to create a high-tech design optimal for these operating conditions, which can positively complement the studies conducted earlier in this direction.

In the study, experimental and theoretical studies were carried out to assess the influence of the shapes of dents in the tank wall on the stress-strain state of the defect zone. By testing fragments of a cylindrical tank, it was found that the most appropriate expression is (5), which could take into account the leaching of the tank wall, resulting in a decrease in the stress concentration index. At the same time, during theoretical studies in this paper, it was found that polynomials determined the stress concentration coefficient, where the obtained analytical expression data were compared with the data determined numerically in the ANSYS program, and it was found that the spread was from 2% to 10%. According to the results of a numerical study of the stress-strain state of the dent zone in the tank wall, graphical dependences of the stress concentration coefficient on the dimensionless depth of the dent for various values of the dimensionless radius of the dents and do not exceed 2% of the indicators that are obtained. At the conclusion of the experimental and numerical studies, a conclusion was made about the degree of influence of the geometric dimensions of the dents on the stress concentration index.

By creating highly productive phytobiomes, selection of new types of biostimulants on the basis of organic substances and microorganism has a decisive role. It could be done by taking into account natural and climatic peculiarities of the region. The article described the importance of sugar sorghum and substantiates the introduction of an adaptive variety to increase the productivity of fodder sorghum and the best option of using growth biostimulants. The results of evaluating the effectiveness of growth biostimulants under laboratory conditions on the main nutritional valuable traits were presented. The treatment of optimal parameters of sugar sorghum seeds with biostimulants in the Research laboratory "Industrial biotechnology" of M. Auezov South Kazakhstan University was determined. It was shown that the "Azotofertil" biostimulator has a high efficiency in pre-sowing seed treatment. For comparative evaluation of potentialities of new biostimulant, MERS biostimulant adapted to climatic conditions was chosen. According to research results, both biostimulants showed high efficiency for seed pre-sowing treatment. The best concentration for treatment of planting material was established. Energy of germination, swelling and the number of germination of seeds of sugar sorghum variety Kazakhstan-16 were determined. In evaluating the activity of biostimulants for efficiency, the dynamics of their friendly germination was traced. At 4% concentration and temperature above 14 °C, the advantage of "Azotofertil" biostimulator based on Azotobacter chroococcum strain was proven. Seeds of sugar sorghum variety Kazakhstan-16 showed the best results with 96 ± 3% germination.

The article of given research presents the mathematical and computer modeling of flame attenuation in narrow channels for different fire extinguishing and explosion suppression compositions. Such kind of flame distribution and attenuation could be considered for different media and channels but in this case it was considered for narrow channels. The effect on the combustion reaction is possible with gas mixture components concentration reducing, cooling the combustion zone and slowing down of chain reactions with the help of a phlegmatizing or inhibiting substances, of which the most universal and perspective are powder materials. Therefore, a necessary condition for solving the problems of developing effective flame arresters is to find common indicators and properties of substances that can become criteria for their phlegmatizing ability. The computer model in MatLab was created for methane allowing the choice of diameter and length of channel and velocity of explosion suppression composition, showing the dependence of temperature on length of channel.

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