Vol 24, No 4 (2023)

With the advent of expanded standards of transfer of information flows (DVBS2X type) from Earth remote sensing spacecraft (remote sensing), there was an opportunity to switch its parameters for transfer of the increased (reduced) data stream to VHSR operating time. For example, switching of modulation and coefficient of interference-immune LDPC (Low Density Parity Check codes) of coding. It allows to reduce power costs for data transmission and to raise the general information flow of data from remote Sensing Satellites (RSS) to Ground Stations (GS) several times. Estimations of theoretically possible transitions to the next transmission mode of data (transition to the level of 0.5-1.5 dB) are made that gives a total gain in increase in a flow of transmitted data can reach 2.0-2.5 times with the possible number of switchings up to 10. In practice, considering the fluctuation nature of the distribution ogtht the signal level during its transmission to Ground Stations, switching is provided in smaller (3-5) number of transitions (at achievement of a power stock 3-5 dB) that leads to a gain in data transmission by 1.5-2.0 times.

It is difficult to imagine modern mechanical engineering without timely and targeted improvement of technological processes, in connection with which new and enhanced traditional methods of manufacturing and processing various types of structures and parts are being developed. One of the ways to reduce the economic costs of machining gears made by traditional methods is the transition to the field of powder metallurgy - powder sintering. This paper presents the possibility of a local increase in the mechanical properties of gears made by powder sintering using laser processing. Laser processing was carried out on a robotic welding and heat strengthening complex, which includes a 6-axis industrial robot, a 2-axis welding positioner, a laser head and a 5 kV ytterbium fiber laser. The high porosity of the sintered material compared to cast billets is a factor limiting the possibility of using laser thermal hardening, as it increases the likelihood of melting the edges of the machined surfaces. The present work is aimed at solving this problem. Before carrying out the experiments, the main quality criteria were identified: “no melting” and “hardening depth”. In the course of a series of experiments on laser thermal hardening, it was possible to significantly increase the hardness of the samples (in the delivered state about 30 HRC), which after processing is in the range from 55 to 65 HRC with a depth of up to 2800 μm on gear teeth made of powder materials. However, open questions remain, which are resolved in performance testing, such as durability and wear.

The study of central configurations, whose concepts and definitions were already formulated by the classics of celestial mechanics - Euler, Lagrange, Laplace and Liouville in the XVIII-XIX centuries, is of interest not only for celestial mechanics, but also for many sections of mathematical analysis, differential equations, analytical mechanics, stellar dynamics and space flight dynamics. In recent decades, there have been opportunities to use the concept of central configurations also in theoretical physics, chemistry, crystallography, etc. We consider planar central configurations, called nested, consisting of polygons sequentially nested one into another, at the vertices of which there are bodies (material points). The existence of nested planar central configurations of trapezoidal type with a sphere in the centre is proved. Early, it was found that abovementioned isolated central configurations exist in the heliocentric rotated coordinate systems. It was supposed only the Newton’s law of attraction is acting between bodies. The Maple software is used to derive the solution of this problem.

The deflection of rods with different widths made of aluminum material was studied using the Taguchi method. The widths of the samples selected for the experiment are 10, 15 and 20 mm, while the applied load is 500, 1000 and 1500 g. The experiments were carried out with the rod in position with one fixed and the other free ends, as well as in position with both free ends. The load was applied to the central point of the rod. The results of the experiment were processed according to the Taguchi L 18 (32×2[1]) plan using the Minitab program. Based on the experimental results, graphs describing the relationship between deflection, load and rod width according to the option of its installation (positioning) are plotted. The study also analysed the results of the experiment. The optimum values of the operated (controlled) deflection parameters were determined to be level 2 ( B ) for placement (positioning) conditions, level 1 for the applied load (500 g) and level 3 (20 mm) for the rod width. According to the results of ANOVA, the main factor affecting the deflection is the load applied to the rod. The relative impact coefficient was 40.12 %. The relative influence coefficient of positioning conditions on deflection was 29.6 8 % and the relative influence coefficient of rod width was 18.30 %. Based on the results of regression analysis, a mathematical model of deflection variation as a function of load and rod width was developed accordingly to the position of rod installation.