The educational process is a complex social management system, the elements of which are combined and interact through information flows. At the same time, information flows can differ in purpose and type of transmitted information. The article is devoted to the substantiation of the need and ways to optimize information flows existing in the educational process. An analysis of the tasks that exist in organizing the educational process is provided using the example of a higher educational institution, the role of modern information technologies that ensure student learning. The educational process is a complex social management system, the elements of which are combined and interact through information flows. At the same time, information flows can differ in purpose and type of transmitted information. The article is devoted to the substantiation of the need and ways to optimize information flows existing in the educational process. An analysis of the tasks that exist in organizing the educational process is provided using the example of a higher educational institution, the role of modern information technologies that ensure student learning. This analysis is also typical not only for higher education institutions, but also for institutions of additional education for adults, during training in which students simultaneously work, are busy with family and study mainly remotely. Representation of the educational process using network models allows them to be formalized, presented in a form convenient for optimization, depending on the task,  corresponding to the objective function and  specified constraints that take into account the specifics of each information model of the educational process. Network models of organizing the educational process, their features and formalization - presentation in a form convenient for modeling and optimization are considered. An analysis of various types of information used in the educational process, methods for its quantitative assessment are carried out. On the basis of the models, the problems that exist in the optimization of information flows and ways of their solution based on the application of mathematical methods of optimization are substantiated. The connection of the problems pertaining to optimization of information flows of the educational process with similar problems of the application of information technologies in various systems of management in social and economic areas is shown

A comparison of operating characteristics has been carried out for laser erosion cleaning (LC) processes studied in recent years and prospective for metalworking manufacturing of products/pieces from a number of carbon steels, cast iron and low-alloy non-ferrous metal alloys from oxidized layers formed as products of gas or other corrosion, often having inhomogeneous structure and porosity. To analyze the efficiency of various (in terms of layer composition) laser processes, it is advisable to use a group of parameters that affect the energy efficiency of LC-processing during the deoxidizing of surfaces. This group includes: a) the time-integrated energy criterion (K_en1s) of heating up to the melting point and/or evaporation temperatures of the layer and, sometimes, a metal substrate located underneath it (or the thermochemical efficiency of the heating, which is derived from the K_en1s), determined from energy consumption; b) irradiation power per surface unit (N₀), or the ratio of N₀ to the thermal conductivity of the layer; c) the pressure amplitude of the shock wave (SW) front in the laser plasma near the surface (P_sw-p) or the dimensionless parameter that includes it, equal to the ratio of P_sw-p to the shear stress for the oxidized layer/metal substrate interface. The dimensionless K_en1s criterion (or similar ones) will be more convenient in some cases for modeling and scaling of LC-processes than dimensional complexes, including thermal criteria such as DMF (“difficulty of melting factor”), which were tested in calculation of plasma spraying of ceramic materials. In this group of efficiency parameters, such a characteristic as the normalized (for example, with Ken1s) Peclet number, which characterizes the rate of propagation of the melting (or evaporation) boundary along the surface when scanning the beam, is also applicable. The considered characteristics, based on preliminary data, make it possible to evaluate the contribution of the mechanisms of the layer removal during pulsed LC, i.e.: 1) thermal effect (“ablation”) with “slow” heating to the melting point of the oxide (or to its evaporation temperature) in thermodynamically quasi-equilibrium regimes; 2) initiation of thermoelastic stresses in the crystal lattice of oxide phases under the impact of high power pulse, resulting in the formation of a network of cracks in the oxide film and its exfoliation from the metal substrate (“spallation”, it is approximately characterized by the maximum stress achieved during LC at the film/substrate interface); 3) plasmadynamic mechanism of the action of pressure on the surface due to the generation of near-surface plasma with a shock wave in it (with a pressure amplitude of up to ≥10 MPa). When assessing LC-processes taking into account efficiency characteristics, it is advisable to use a special set of verified data selected according to the thermophysical properties of layers of an analyzed type.

Resistance projection welding of various materials and alloys has become widespread in various branches of the machine-building industry due to the high productivity of the process, technological and economic parameters of manufacture of  manufacture  and  a  wide  diversity  of  types  of  welded  joints.  Despite  its  widespread  use,  technological  processes of resistance projection welding in production conditions are not always able to provide consistently high quality of welded joints. Due to the fact that the calculation of welding operation parameters is carried out according to a universal methodology based on the heat balance equation, there are no recommended parameters for different types of joints, which, as a rule, leads to an overestimation or underestimation of welding current values. Incorrectly defined parameters of projection welding lead to the appearance of a large number of defects in T-shaped joints. Mathematical modeling is one of the effective ways to improve  the  quality  of  welded  joints  obtained  by  resistance  projection  welding.  Existing  mathematical  models  of the projection welding process, as a rule, have significant approximations in setting important parameters of the operation from the point of view of the welding cycle, therefore, the development of a model that takes them into account is an urgent task. The paper examines the developed method of mathematical modeling of projection welding process of T-shaped joints, taking into account the phase control of the heat input power, which is used to determine the influence of energy mode parameters on displacement characteristics of movable electrode of a contact welding machine. Based on the results of mathematical modeling, recommended dependences of the parameters of resistance projection welding modes of T-shaped joints have been obtained. The model of the resistance projection welding process of T-shaped joints is implemented in the ANSYS software product. The adequacy of the developed mathematical modeling methodology has been confirmed by experimental studies of the resistance projection welding process.

The scheme of a device for processing lenses with convex-concave spherical surfaces of the negative meniscus type of average diameter, which allows flexible and wide control over the process of simultaneous bilateral abrasive shaping of the noted optical parts, is considered in the paper. Mathematical modeling of the processing of spherical surfaces using the free grinding method using a tool in the form of a mushroom and a cup was carried out. An analytical expression is obtained for calculating cutting paths, which, according to F. Preston’s formula, are proportional to the amount of material removed from the work-piece being processed. The calculation of cutting paths in the diametrical sections of the processed spherical surfaces was carried out. The calculation was performed for various values of such parameters of processing modes as the amplitude of the reciprocating rotational movement of the tools and the number of their double strokes per minute, as well as the rotation speed of the lens. In this case, the section with the greatest divergence of sliding paths was considered and the relative value of these paths was determined, which is proportional to the processing accuracy. Research has been carried out to establish that when correcting macro-errors on the actuating surface of the lens, it is most effective to change the amplitude of the reciprocating rotational movement of the tools, and these changes should be made within the range from the minimum value of this amplitude, determined by the design features of the specific basic technological equipment, to its value 0.65 of the diameter of the work-piece. In this case, to minimize local errors of the latter, it is advisable to set its rotation speed to 60–70 rpm.

An analysis has been made of the reasons for the formation  of internal and external corrosion of silver coins, which are based on copper (23–70 %) and iron (11 %) impurities of varying concentrations depending on the rank and denomination. Existing chemical cleaning methods using acids and salts are mainly effective in removing thin oxide films and can lead to destruction of the internal structure of coins. Experimental studies were conducted on two silvrt coins with a face value of 20 kopecks; their metal alloy: 50 % silver and 50 % copper in the original VF (Very Fine) rating condition with films of 0.1 to 0.5 mm thickness made of silver carbonate Ag₂CO₃, argentite Ag₂S, and silver oxide Ag₂O. A Wattsan FL TT laser marker with an IPG ytterbium fiber emitter (operating wavelength 1064 nm, output power 15.5 W) was used for cleaning. The EzCAD 2.14 software was used to control the parameters for moving the laser marker beam. The optimal parameters for processing silver coins are: speed of 5000 mm/s; the pulse repetition frequency of 200 kHz and the step between the processing lines of 0.01 mm, which ensures a two-fold overlap of the processing radiation along the x-axis and a five-fold overlap along the y-axis. In this case, for greater uniformity of the effect of laser radiation on the surface, it is advisable to carry out processing in several passes with alternating directions. The best surface quality was obtained with a total of 6 passes: 3 of which were parallel to the base axis х, 3 were at an angle of 45°.  A visual assessment of the coin surface quality during cleaning  process was carried out using a portable digital USB microscope GUANMOU AN104/F210 at 50x magnification. The quality of the formed mirror surface was assessed by measuring the reflection coefficient on the obverse side in the visible spectral range on a Photon RT Essentoptics spectrophotometer. The use of a laser cleaning method for silver coins has improved their condition from the original VF (Very Fine) to XF or EF (Extremely fine), and in combination with final polishing (Fluoropol M with a grain size of 0.6÷0.8 μm in a solution of Glycerin C₃H₈O₃) to the UNC (Uncirculated) condition, which is confirmed by a significant increase of 4–6 times in the reflection coefficient of the mirror surface.

The article presents a diagram of a modernized machine with planetary movement of the tool for grinding balls of colored stone and test results when processing serpentinite. There are various methods and devices for processing metal balls using abrasive methods used in the production of bearings. These devices simulate the operation of a thrust bearing. One of the tools contains a V-shaped groove, in which the workpieces being processed receive predominantly biaxial rotation. Quantitative criteria for evaluating the ball processing process are productivity, dimensional accuracy, spherical shape and surface roughness. Currently, balls made of non-metallic materials are also used: ceramics, glass, glass ceramics and stones, which differ from steel ones in their physical and mechanical properties, primarily such as fragility and lower strength. This is especially noticeable when processing minerals used in the jewelry industry, which differ in structure, the presence of layering,   internal defects, etc. All this makes it necessary to process such materials under conditions different from the conditions for processing steel balls (lower pressure forces, speeds). However, insufficient attention has been paid to issues devoted to methods of processing balls made of fragile materials, including jewelry stones. In many cases, the necessary methods and conditions for processing such materials are determined throughout practice by trial and error. The increasing volume of production of beads for making jewelry from natural stone necessitates comprehensive research and generalization of the results of these studies in order to develop recommendations for their practical use. In this work, we propose a method for processing balls in a device that ensures planetary motion of the balls due to the fact that the disk-shaped tool receives periodic rotation from the friction force that occurs when its side surface touches a table performing planetary motion. As a result, the balls located in the conical sockets of the disk receive accelerated motion and roll along a cycloid trajectory. The additional path that the balls travel in the same time, as well as the change in the ratio of the angles of rotation of the balls around their three axes, create conditions for increasing the productivity and accuracy of processing.  The experiments were carried out on a pilot plant when processing workpieces made of serpentinite, which belongs to the group of soft stones. The results of the work showed that the batch processing time for each part grinding ope-ration until dimensional stabilization is achieved does not exceed 30 minutes. The amount of allowance removal and the degree to which the required ball dimensional accuracy and roughness are achieved are determined by the size of the abrasive grain.

An increase in one or another damaging factor leads to a decrease in strength or wear resistance. The interaction of damaging phenomena turns out to be complex. If contact load (friction and wear) is added to cyclic loading or cyclic freeze-thaw (mechanical fatigue), then the reliability and durability of the system receiving them can either decrease, increase, or remain at the same level. The results depend on the conditions of interaction of damaging phenomena. At the intersection of tribology and mechanics of fatigue fracture in the mid-1980s, thanks to the research of Professor Sosnovsky L.A., tribo-fatigue arose – a science that studies not the mutual influence of individual damaging factors, but a complex combination of various damaging phenomena.  As a result of this interaction, a special type of degradation of structural concrete of berthing structures is revealed – complex wear-fatigue damage. The conditions and patterns of such damage to berthing structures are studied by tribo-fatigue. Design of reinforced concrete structures based on limit states is a traditional method. For critical structures of berth structures, resource-based design is advisable. Technical resource is an indicator of durability. This is the operating time of an object, in this case reinforced concrete berth structures, from the start of operation until the onset of the limit state. Sea port facilities on the coast of the Far Eastern seas, a distinctive feature of their operation being the climatic conditions of Sakhalin Island, have been studied. The structures of port facilities are affected by waves. In winter, when the temperature drops to below zero, structures become icy in variable water levels and are affected by floating ice.

This article examines the peculiarities of microclimate formation when using radiant-convective heating device - radiator. The main purpose of the work is to determine the advantages and disadvantages of radiator heating in residential premises, to assess the influence of  window sizes, room dimensions and the device on the formation of the microclimate in the room. The study includes the analysis of temperature and velocity fields in three representative rooms of different sizes and configurations. The authors identify the disadvantages of current heating systems associated with the uneven temperature distribution across the height of the room and the formation of zones of reduced comfort near the windows. The work examines three typical rooms for which mathematical modeling of thermal processes is carried out using differential equations to describe the processes of heat and mass transfer. The main attention is paid to the influence of window sizes, room dimensions and heating devices on the microclimate. The authors note that radiators do not always cover the entire width of windows, which leads to the formation of cold zones at their edges, the penetration of cold air deeper into the room and the formation of discomfort zones inside the room. The simulation results show that the indoor air parameters comply with GOST standards, however, the subjective comfort of residents may decrease due to uneven temperature distribution. In conclusion, it is concluded that it is necessary to develop new types of heating devices that will more effectively cope with the task of maintaining a comfortable microclimate and will eliminate the negative impact of cold air penetration through window openings on comfort.

The article considers the influence of climatic factors on energy and water consumption of the urban water supply system. The purpose of the study is to identify the relationships between outdoor air temperature, precipitation and  load on the water supply system to substantiate the factors necessary for creating seasonal models of water consumption and increаsing the energy efficiency of water intakes. The objective of the scientific work was to test the hypothesis, according to which an increase in air temperature leads to an increase in water consumption and, as a consequence, to an increase in energy costs for the operation of pumping stations and water treatment systems. At the same time, it was assumed that precipitation would have the opposite effect, reducing water consumption during periods of intense rainfall. The work used correlation analysis to assess the strength and direction of the relationships between air temperature, precipitation and energy and water consumption parameters. Regression analysis was used to quantitatively assess the impact of climatic factors. The moving average method was used to smooth the data and reduce the spread of random fluctuations. Data filtering and cutting methods were also used, which made it possible to divide them by temperature thresholds and conduct separate studies for different ranges. The obtained results demonstrate that the growth of energy consumption is closely related to the increase in water demand, which increases with each degree of outside air temperature. This is explained by the expected increase in water consumption for irrigation and household needs during warm periods. Above 25 °C, the temperature factor determined 15.8 % of water consumption, which also coincided with the growth of this contribution to the electricity consumption of the system (15.6 %). However, when analyzing data in the area of negative temperatures, no obvious relationship was observed between temperature and water demand. At the same time, a correlation was found between temperature and electricity consumption, which is associated with additional costs for maintaining the water supply system in cold climates. Conclusions are made about the need for further study of additional variables, such as types of weekdays (working days, weekends, holidays), seasons of the year, as well as other socio-economic factors affecting water consumption and energy costs. The comprehensive results of the work can be used for planning the work of water utilities, managing energy resources and developing strategies to improve energy efficiency in water supply systems.