Vol 21, No 3 (2020)

One of the most important tasks of the Federal Space Program of Russia for the period until 2025 is the creation of spacecraft for remote sensing of the Earth. An integral part of the design of this class spacecraft is the determination of the parameters of the orbits that are most effective from the standpoint of information content, energy supply and the duration of active existence. In orbital flight, the temperature state of spacecraft in a complex way varies in time and space. The inhomogeneous temperature field of the structural elements of spacecraft can cause shape distortion, which adversely affects the performance of targets. A technique for a comprehensive analysis and determination of the platform composite design parameters, which is part of the spacecraft for remote sensing of the Earth is proposed. The conditions of thermal loading for flight in a sun-synchronous orbit are considered and mathematical modeling of the operating conditions that ensure the effective operation of such spacecraft is performed. The results of modeling the thermal regime of options for composite platform designs are presented. The technique will be useful in determining the complex of orbital characteristics of the Earth remote sensing satellite at the stage of technical proposals.

A significant proportion of mechanical losses in internal combustion engines accounted for mechanical losses in the cylinder-piston group. Depending on the operating modes of the internal combustion engine, contact interaction in the piston-cylinder pair is possible, which leads to wear of the working surfaces of the resource-determining elements and a decrease in the operational life of the power unit as a whole, in connection with which the reduction of friction losses in the internal combustion engine elements and the piston - cylinder liner coupling in particular is relevant. Both domestic and foreign researchers are engaged in the solution of the above described problems, various profiles of pistons, methods of calculating the parameters of the oil layer are proposed, but the practical state of the issue determines the relevance of research in this direction. The paper considers the possibility of reducing the wear of piston skirts by reducing the contact surface in conjugation and providing an oil film in the friction zone, regardless of engine operating conditions. This opportunity is realized by forming a certain macro profile on the working surface of the piston skirt. The formation of the macrorelief was carried out by means of surface plastic deformation, with the reciprocating movement of a spherical tool on the machined surface.

Engineering for the cement industry is part of the heavy industry. The cement industry is the main supplier of raw materials for the production of concrete and reinforced concrete. For grinding cement, two types of mills are used - ball and roller. Recent decades have proven the great effectiveness of a vertical roller mill for grinding raw materials. Its effectiveness, combined with the implementation of drying, grinding and separation in one unit, gives it an undeniable advantage over a ball mill. This explains the significant increase in the share of roller mills in the cement mill market. The grinding process in such mills occurs due to abrasion, respectively, in the process of work wear of the rubbing parts of the mill occurs. The work evaluated the performance of a mill with smooth disk rolls. During the study, the cause of the destruction of the sectors of the mill produced by FLSmidth, operating in the Russian Federation, was identified. The study revealed the causes of the destruction of the details of the roller mill: with the simultaneous impact of the workload and the displacement of the sectors resulting from intensive wear, the total equivalent stresses exceed the value of the endurance limit under cyclic loading. Therefore, the accumulation of fatigue damage to the material, the formation and growth of cracks, which adversely affects the performance of the mill. A number of measures have been proposed to increase the operability of mills of this design.

The article analyzes the state of the phosphate raw material base in Russia and its role in the economic development of the country and in domestic agriculture especially. The problems that prevent the creation of a modern powerful phosphate production capable of satisfying the existing demands of agriculture in phosphoric mineral fertilizers are highlighted. The possible directions of the development of the phosphorus industry in the regions for the near and distant prospects are analyzed. The aim of the article is to analyze the current state of the domestic mineral resource base to produce phosphorus fertilizers, the acute shortage of which hinders the development of the country's agriculture. Actual base for research was mainly processed materials from specialized scientific articles and publicly available publications. In addition, data collected by the authors during thirty years of studying phosphorite deposits in Russia and foreign countries were involved. The analysis of published materials of leading Russian producers of phosphorus products, mining companies, databases of specialized federal and regional geological companies. It is concluded that before the country's geological services, the most important task remains to identify deposits of high-quality phosphate ores, and especially in Siberia and the Russian Far East. Significant prospects for the development of these regions are opened by the Northern Sea Route. The planned pace of its development offers unique opportunities for the economic development of the Taimyr-Anabar region, where huge resources of apatite-bearing carbonatites of the Tomptor alkaline massif and Meimech-Kotuy province are concentrated.

From the old ancient types of roof and dome construction, various forms of shells have been discovered which attract special attention. A shell is a structure composed of sheet material so that the curvature plays an important role in the structural behaviour, realizing its spatial form. There are different types of shells, namely thick and thin shells. G. Brankov, S.N. Krivoshapko, V.N. Ivanov, and V.A. Romanova made interesting researches of shells in the form of umbrella and umbrella-type surfaces. The term “nonlinear” refers to a given structure undergoing a change in stiffness in its loaded state. There are basically three different types of nonlinearities: geometric, physical and contact (boundary condition nonlinearity). For further analysis of the stress-strain state, a paraboloid with an inner radius of 4 m and an outer radius of 20 m and the number of waves equal to 6 was considered. The test shell is made of reinforced concrete. The minimum load parameter at which the shell loses stability indicates a more than three times the margin.