The purpose of the presented research work was to evaluate various factors affecting the wear process of parts with cylindrical friction surfaces, which will allow to simulate their contact interaction taking into account the parameters of roughness and physico-mechanical properties of the surface layer.

Methods. Modeling of the process of contact interaction of cylindrical surfaces is performed by considering the sliding contact of two cylindrical surfaces, represented as the contact of a smooth elastic sleeve and a shaft with the given (equivalent) values of roughness parameters. The modeling takes into account elastic deformations of conjugate bodies, as well as elastic-plastic deformations of micro-dimensions. When modeling a geometric contact, a certain section of the cylindrical surface is considered, located along the plane forming in the section of the cylinder passing through its axis. This section of the cylindrical surface is considered as an elementary area of the total geometric contact area of cylindrical surfaces and is a section of a cylindrical surface, the width of which is determined by the length of the larger axis of the ellipse at the base of the elliptical paraboloid when modeling a rough surface.

Results. Based on the modeling of the contact interaction of cylindrical surfaces, the main factors influencing the process of their wear are established, such as: the actual contact area; the amount of convergence of the contacting surfaces; the actual pressure; the intensity of wear of the mating cylindrical surfaces. A kinetic wear model is proposed that takes into account the parameters of the roughness and physico-mechanical properties of the surface layer.

Conclusion. Based on the proposed model of wear of parts with cylindrical friction surfaces, taking into account the parameters of roughness and physico-mechanical properties of the surface layer, it became possible to provide the required intensity of wear of cylindrical friction surfaces.

Purpose of research. The study is devoted to the study of the influence of the angle of inclination of the receiving surface with a convex and concave profile on the change in the displacement of a single deposited layer during additive shaping by an electric arc in a protective gas medium. Experimental studies on shaping on receiving surfaces with different angles of inclination have been carried out. Based on the samples obtained by electric arc welding in a protective gas medium, the displacement values of the individual deposited layers are determined. Since the angle of inclination of the receiving surface can affect the displacement of a single deposited layer during additive shaping by an electric arc in a protective environment, a one-factor dispersion analysis was performed.

Methods. Methods of organization and planning of the experiment, mathematical processing of experimental results, single-factor analysis of variance.

Results. As a result of the dispersion analysis, it was revealed that the angle of inclination of the receiving surface during additive shaping of products affects the displacement of a single deposited layer and is a significant parameter during additive shaping by an electric arc in a protective gas environment. In particular, it was found that the significance criterion for the slope angle is p < 0.01. In turn, for a convex surface it is p < 0.03, for a concave surface it is p < 0.004. Comparing the results, it can be seen that the criterion is more significant for a concave surface.

Conclusion. It is determined that the angle of inclination of the receiving surface significantly affects the change in the displacement of a single deposited layer during additive shaping by an electric arc in the sphere of protective gas. Therefore, the angle of inclination of the receiving surface with a convex and concave profile is significant and should be taken into account when designing technological processes for additive shaping of products by an electric arc in a protective environment.

Purpose of research. Due to the growing demand for energy-saving technologies around the world and in the Russian Federation, thermal energy storage devices are interesting for research. There are various ways to accumulate thermal energy, one of them is using thermal accumulators at a phase transition. These devices will be the target of research for further development. 

Methods. One of the most effective heat-storing substances of phase transition is paraffin. In the process of reviewing the scientific literature, three main areas for the use of thermal accumulators of phase transition were identified: heating and hot water supply systems from traditional energy sources, heating and hot water supply systems from renewable energy sources, pre-start preparation internal combustion engines. An unpackaged heat accumulator with a phase change can be used to accumulate low-grade heat in the return pipeline of a heating system; another type of accumulator will be effective when charged from a solar energy source. To preheat the internal combustion engine in a car before starting it, you can also use a heat accumulator. 

Results. The review and analytical study of existing phase change heat accumulators showed that existing phase change heat accumulators based on paraffin can be improved by trying different arrangement configurations, using polymer materials to supply coolant, and looking for ways to reduce the volume and weight of their design. 

Conclusion. Further comprehensive study of phase transition heat accumulators will make it possible to find effective ways to use it in individual heating and hot water supply systems, as well as in internal combustion engines. Look for new directions for their application, which will be the goal of further research.

Purpose of research: development of a methodology for selecting energy-efficient thermal insulation materials using the Dynamo visual programming environment in order to increase the energy efficiency of building envelopes and structures.

Methods. The study was carried out using theoretical and practical methods. The theoretical study was carried out based on an analysis of scientific publications, as well as regulatory requirements in the field of energy efficiency. The practical study was carried out using the implementation of the methodology for selecting thermal insulation materials in the Revit software package using the Dynamo visual programming environment.

Results. The capabilities of the visual programming environment Dynamo have been studied, allowing to automate the modeling and development of design documentation in the Revit software package, automate the process of reinforcing structures, designing utility networks and systems, creating automated quality control systems for BIM models, etc. Particular attention in the work is paid to the capabilities of Dynamo for automation performing thermal engineering calculations and selecting energy-efficient thermal insulation materials. A library of thermal insulation materials has been created, which can be supplemented and copied from one project to another using standard Revit functionality. Two Dynamo scripts have been created. The result of the work of the first is the complete automation of thermal engineering calculations in Revit, the result of the work of the second is the selection of thermal insulation material taking into account the requirements for thermal protection of buildings. A methodology has been developed for selecting energy-efficient thermal insulation materials using the Dynamo visual programming environment. The reliability of calculations obtained on the basis of developed scripts is confirmed by the results of manual calculations.

Conclusion. The use of modern BIM technologies when choosing energy-efficient thermal insulation materials allows you to optimize the calculation process, and also makes it possible to find the most cost-effective solutions to reduce costs and increases design speed.

Purpose of research. The use of liquefied natural gas (LNG) as an energy carrier is expanding annually. Therefore, the purpose of this article is to analyze the regulatory requirements for the structure protection from the cryogenic liquid spill such as LNG. The article also evaluates the ability of fireprotective materials to resist not only hightemperature influences, but also low-temperature ones.

Methods. The article discusses the main methods of material testings to counteract the cryogenic liquid spill and the possibility of using fireprotective products as cryoprotective materials. The results of testing the protective system manufactured by LLC "PROSASK" are shown and analyzed. The object of the study is a fire-retardant structural system consisting of "PROSASK Fire Panel" plates. The protective system consists of two layers of flame-retardant plates "PROSASK Fire Panel" with a non-flammable membrane " in the middle, manufactured by LLC "PROSASK". And the subject of the research is the cryoprotective function of this system.

Results. The average temperature of the sample after 60 minutes cryogenic exposure was - 53 °C, conclusions were drawn about the expediency of conducting successive tests for low-temperature and fire exposure due to the high probability of fire after the cryogenic liquid spill in the presence of a flame source.

Conclusion. The article shows and analyzes the test results of the protective system manufactured by LLC "PROSASK". With the correct choice of steel grade (including the requirement for impact strength) of load-bearing structures of oil and gas facilities, it can be concluded that structures protected by a structural fire protection system with PROSASK Firepanel plates are operable after an hour of cryogenic exposure.

Purpose of reseach. The main goal of this study is to evaluate the effectiveness of using non-metallic meshes made of high-strength fibres in the reinforcement of folded elements. For this purpose, methods for calculating folded structures made of concrete composites are investigated, and a comparative calculation of the structure with various reinforcement parameters is performed.

Methods. The study analyzes an algorithm for calculating reinforced cement structures using the limit force method with the transition from the original folded section to the reduced section. Using the method under study, we calculated a thin folded panel reinforced with meshes of various materials with a constant mesh reinforcement coefficient. Welded steel mesh, high-strength glass fiber textile mesh and carbon fiber textile mesh were considered as reinforcement. Simultaneously, the inverse problem was solved, within the framework of which the reinforcement coefficient necessary to ensure the same load-bearing capacity of the section when using different reinforcing materials was selected.

Results. Sample of section reinforced with carbon fiber mesh exhibit the greatest ultimate load of 14.5 kNm . Sample of section reinforced with  glass fiber and welded steel mesh exhibit ultimate load of 6.4 kNm and 1.72 kNm, respectively. Inverse problem was also solved. The reinforcement ratio necessary to ensure equal load-bearing capacity of the panel reinforced with different materials was determined. The reinforcement ratios of steel mesh (S), AR-glass textile (G) and carbon textile (C) were found as S:G:C=1:0.26:0.12.

Conclusion. Reinforcement of concrete composites with non-metallic meshes has significant potential for the design of lightweight spatial structures for roofing buildings and structures. The use of high-strength reinforcing textile meshes makes it possible to achieve panel strength comparable to that of traditional reinforced concrete products. It is necessary to consider other strength calculations of folded panels reinforced with non-metallic meshes and experimentally confirm the results of analytical calculations.

Purpose of research. Bridge constructions are frequently subjected to harsh circumstances such as severe weather, earthquakes, traffic accidents, and even explosives. Bridge structures may lose some of their important structural parts (e.g., cables or piers) as a result of such intense external stresses, and further collapse is possible, as progressive collapse is often caused by the abrupt loss of one or more critical structural components. Cable-stayed bridges have very tiny crosssectional areas and are subjected to high loads. Such strong pressures can destroy anchoring zones due to large stress concentrations, resulting in cable loss.  Bridges with cable stays must be thoroughly investigated for the danger of progressive collapse induced by cable loss scenarios. Suggests considering the most common cable failure scenarios throughout the design process. To evaluate the effect of cable loss, do a static analysis with a (DAF) of two. There are two primary ways for avoiding progressive collapse. First, adopt structural or non-structural measures to provide a high level of safety against localized collapse. Second, prevent failures from spreading by establishing a solid foundation that allows for local failures.

Methods. Materials and methods. Damage to cables in the mathematical modeling of cable-stayed bridges. A continuous beam suspended from tension elements (cables) forms the basis of the conceptual model. His strength calculation plan is by comparing stiffness and flexibility matrices of intact and damaged systems. The stiffness matrix for an intact system is calculated using its reduced shape. The flexibility matrix is then calculated by inverting the reduced stiffness matrix. The conceptual model is interactive. As a result, the stiffness matrix is infinite. For direct analytical calculations, the parameter n is set as the ratio of the stiffness of the system ( = ), and a reduced form of the stiffness matrix is obtained to obtain an intact.

Results. The secant module seems to give a very good approximation, since the error remains less than 1% for cables up to 300 m long and less than 2% for cables up to 750 m long. Russians Russian Bridge has a length of 135.77 meters and the longest cable is 579.57 meters, as a result, the error rate of cables on the Russian Bridge will remain less than 1% for some cables and less than 2% for some cables. Considering that the modulus of elasticity of the steel material of the cable is rarely known with an accuracy of more than 2-3%, it is obvious that the method for determining the secant modulus would be suitable for all practical purposes. The tangent module is often easier to use than the secant module, since it is only necessary to know the voltage of the cable in its initial state. On the other hand, the tangent module can lead to erroneous conclusions with a long cable length and a large traffic-to-idle ratio, as shown in Figure 8.

Conclusion. The distance between two adjacent cables on modern bridges is significantly less than on older bridges. As a result, in the event of a car accident or explosion on the new bridge, several cables will fail. As a result, it was proposed that bridge designers take into account the rupture of all cables within a radius of 10 meters. Several studies have been conducted to find DAF in bridges. According to this study, having a father of two is not always safe. Although a recent study shows that the proposed DAD is safe for cable construction, that is, it is unsafe for structures of pylons or beams with negative moments.

Purpose of reseach. The aim of the work is to determine the parameters of the resulting flow in the interaction of counter-misaligned air flows to ensure an intensive decrease in air velocity in production and technological premises of small volume. To achieve this goal, it is necessary to solve such tasks as analyzing existing theoretical provisions and methods for calculating air distribution systems for small production and technological premises; development of a mathematical model of the process of interaction of oncoming incompatible flows and to determine the parameters of the resulting air flow depending on the geometric characteristics of the device. The object of the study is the supply ventilation systems in industrial and technological premises of small volume with insignificant thermal loads. The subject of the study is the processes of formation of the resulting air flow created by the interaction of countermisaligned air flows.

Methods. Methods of mathematical modeling of air flow motion based on the equations of aerodynamics.

Results. The aerodynamic characteristics of the resulting jet are obtained – the Boussinesq coefficient and the velocity field coefficient.

Conclusion. In the ambiguities, between two-meter-long-range extravehicular jets and two-meter-long-range converging streams in the inner regions, a spatial vortex zone is formed with a maximum extravehicular gradient velocity. At the boundary of the jet stream there is an intense interaction with the surrounding air, the vector of the propeller is directed by the opposite direction, and the quantity of the speed of the plane depends on the speed of the jet, which changes the nature of the swirling movements. The results show that the actual level of overshoot during a load surge is determined in the first approximation by the increment value multiplied by the difference in the values of thermal conductivity, winding-oil at the initial and final temperatures of the oils in the channels of the cooled windings, and this difference itself depends on the magnitude of the incremental damage. Optimal factor intervals for the values of the maximum value of the functions are obtained: t – from 40 to 120; ρ – from 800 to 900; c – from 1.4 to 2.3.

Purpose of research. The goal of the work is to develop and justify a cognitive peer-to-peer infrastructure that will improve the conditions for collective work on projects based on agile methodology. Cognitive architecture is defined as a structure that ensures the implementation of anthropomorphic and neuromorphic functions in natural or artificial systems. The proposed approach is based on organizing the interaction of the collective intelligence of members of an agile team and artificial intelligence, represented by trained artificial neural networks. When forming an agile team, it is proposed to take into account the structure of the cognitive sphere in the structure of the mental processes of a human cognitive agent.

Methods. Domain knowledge is determined based on the collective intelligence of the agile team members and the training of artificial neural networks. It is assumed that artificial neural networks are available to all members of an agile team and implement the functions of collective artificial intelligence, provided that their training uses the professionalism and experience of a person in a natural social environment. Mental operations such as analysis, partitioning (modularization), comparison, abstraction, synthesis, generalization, classification, concretization, known from general psychology courses, are interpreted not only as a result of human activity, but also as the functionality of a program. Some elements of the cognitive sphere processes “memory” and “speech” are realized in a similar way.

Results. The system is implemented on the basis of a peer-to-peer computer network that provides communications between all artificial and natural participants in the cognitive process during the design process. A conceptual model of a cognitive collective intelligence cell is proposed, combining elements of the actual collective intelligence of agile agents with the collective artificial intelligence of agents based on neural networks. In an expert assessment of the quality of individual design stages, it was proposed to use tagging based on the emotional-volitional and motivational mental processes of individuals.

Conclusion. Cognitive information processing is based on the idea of modeling human thinking processes in computer systems. In the system under consideration, this includes natural language processing, written speech recognition, associated with understanding information through software imitation of human intelligence. The accepted concept involves the implementation of collective intelligence not only artificially, but also by organizing convenient interaction between participants in an intellectual chat. Artificial intelligence, also collective, is implemented using initially trained and further trained neural networks.

The purpose of the research is a comprehensive study of the process line of a multifunctional fuel gas preparation unit (MGPU), creation of a mathematical model capable of predicting and controlling gas dryness in the process of MGPU operation, as well as determination of optimal parameters of the unit operation to improve accident-free operation and high productivity of the equipment using treated gas.

Methods. Mathematical modeling with the use of multiple regression model for prediction of dew point temperature and its influence on accident-free operation of the plant was carried out. The adequacy of the model was confirmed by the coefficient of determination and Fisher's criterion. An analysis of the limiting factors for the accident-free operation of the MGPU, including temperature, pressure and gas composition, is also presented. The accuracy of numerical modeling of the trouble-free operation of the MUPG process line based on the developed model of multiple regression of gas dryness was estimated using paired correlation coefficients and elasticity coefficients. 

Results. In the course of the work, the accident-free operation of the process line of MGPU was modeled based on the developed multiple regression model of gas dryness. The following interpretation of the model parameters is possible: increasing factor X₁ by 1 leads to an average decrease in Y by 0.279; increasing factor X₂ by 1 leads to an average increase in Y by 0.46; increasing factor X₃ by 1 leads to an average increase in Y by 0.000418; increasing factor X₄ by 1 leads to an average increase in Y by 13.288; increasing factor X₅ by 1 leads to an average decrease in Y by 13.337; increasing factor X₆ by 1 leads to an average decrease in Y by 0. According to the maximum coefficient β₂=0.384 we can conclude that the factor X₂ has the greatest influence on the result Y. Statistical significance of the equation was tested using the coefficient of determination and Fisher's criterion. According to the assessment of the accuracy of numerical modeling of the trouble-free operation of the MUPG process line, based on the developed model of multiple regression of gas dryness, a strong linear relationship between X₁ and Y, a low linear relationship between X₂ and Y, a low linear relationship between X₃ and Y, a moderate linear relationship between X₄ and Y, a moderate linear relationship between X₅ and Y, moderate linear relationship between X₆ and Y.

Conclusion. It was found that in the investigated situation: "in the possibility of prediction and control of gas dryness: justification of the hypothesis about the possibility of prediction of dew point temperature and its influence on accident-free operation" the parameters of the model are statistically significant.  

Purpose of research. An analysis of the problems and tasks in conducting combat operations in infectious diseases departments of medical institutions of the country allows us to talk about serious challenges facing the personnel of fire and rescue units. To develop approaches to solving these challenges, it is necessary to determine time periods for disinfection, as well as to formalize a regulatory algorithm for determining the parameters of personal respiratory protection equipment for integration into a decision support system when managing units of the gas and smoke protection service (GDSS) when extinguishing fires.

Methods. Analysis of descriptions of fires in medical institutions, numerical methods of mathematical modeling, as well as experimental studies made it possible to establish the average time pressure values in the cylinders of the breathing apparatus of gas and smoke protectors carrying out combat operations to extinguish fires in conditions of possible infection with infectious diseases, as well as the amount of time required for personnel to carrying out appropriate disinfection measures.

Results. In the course of the study, the authors found that: the average pressure values in the cylinders of breathing apparatus, which gas and smoke protection service members can use as much as possible when traveling to the fire and working on site, are 170 MPa; the lowest pressure in the cylinders of breathing apparatus when included in the unit is 2600 MPa; the time required to implement disinfection measures ranges from 81 seconds to 429 seconds.

Conclusion. Algorithmization of the calculation of air reserves in personal respiratory and vision protection equipment (RPE), a harmonious combination of artificial intelligence and computer vision technologies creates additional prerequisites for the creation of new forms and opportunities for integration into a comprehensive management decision support system for the decision maker at the fire site.

Purpose of research. Currently, mathematical methods of video sequence analysis represent a structured set of approaches to image recognition based on the difference in the glow of different image areas. Many of these values are described using mathematical dependencies, however, existing approaches work only for standard images obtained during video data processing. The purpose of this study is to develop a new approach to analyzing images obtained, including those using terahertz radiation, which has specific characteristics, both physical and mathematical.

Methods. The following theoretical and empirical scientific methods were used in this study. Analysis (the analysis of the currently known mathematical methods of image processing in order to recognize images is carried out). Synthesis (a fundamentally new approach to security systems is proposed, which is a single system consisting of separate interconnected subsystems). Modeling (an information model of a security system based on ACS has been developed using a system for analyzing and recognizing potentially dangerous objects based on a real-time video stream).

Mathematization (the image analysis system is described in the language of mathematical laws and formulas).

Results. As a result of the research based on the analysis of modern materials, the concept of a security system based on real-time video sequence analysis with the use of advanced object scanning technologies is proposed in the future. As the main innovation, an improved Viola-Jones image analysis method is proposed using an additional set characterizing the feature space of objects in the terahertz radiation range.

Conclusion. The use of high-frequency scanning technologies with intelligent object image recognition systems in real time will significantly reduce the risks of intruders entering protected facilities, as well as increase the safety of citizens with relatively low costs for the development and implementation of upgraded security systems.

The purpose of the work is to study and develop methods for localizing an ultra-light unmanned aerial vehicle (UAV) in a closed environment saturated with objects, based on semantic and topological data obtained from the environment. The purpose of the work is also to develop software and select a hardware complex for launching and testing the developed solution.

Methods. To achieve this goal, a review and comparison of existing solutions were conducted. Optimization of the neural network architecture for detecting objects. Development of an algorithm for compiling a graph of objects reflecting their relationships. Development of an algorithm for comparing graphs to determine the position of the UAV. Implementation of a solution to improve the accuracy of determining the geometric center of detected objects. Use of keypoint detection methods (SIFT, SURF) to solve the problem of identifying objects of the same class.

Results. The result of the work is a developed localization method based on semantic and topological data obtained from the environment. A software package based on the ROS2 humble platform and implemented on the hardware based on the Rockchip 3588 board was also developed. The experiments were conducted on ready-made datasets (KUM dataset) and using UAVs indoors.

Conclusion. The developed localization system is a promising step towards creating efficient and flexible systems capable of operating in complex conditions. In the future, it is planned to integrate this method with other sensors to improve robustness in dynamic conditions, add visual odometry algorithms to improve the accuracy of UAV localization, and expand the application of the system to UAVs used in other industries (infrastructure inspection, search and rescue).

Purpose of the research is to consider advantages of application of variational integrators on Lie groups in problems of physically correct modeling of dynamics of mechanical systems and to compare them with classical nonvariational integrators.

Methods. To demonstrate the possibilities of variational integrators on Lie groups, a mathematical model of the dynamics of a physical pendulum was developed. Methods of variational calculus and methods of Lie group theory were used to construct a mathematical model of the dynamics of a physical pendulum. The Runge-Kutta method of the 4th order was used for comparative analysis of variational and nonvariational integrators. Modeling was carried out in MATLAB software.

Results. In this research, a variational integrator algorithm on Lie groups was developed to model the dynamics of a physical pendulum. To compare the variational integrators and the 4th order Runge-Kutta method, plots were constructed to show how the angular velocity along the axes, orthogonal error, total energy, and angular momentum change over time. The graphs demonstrate that although the angular velocity is the same for both methods, the Runge-Kutta method does not preserve the geometric structure of the continuous system and does not preserve the basic constant quantities of the modeled system, namely mechanical energy and momentum.

Conclusion. Numerical modeling has shown that the preservation of symplectic properties of systems and the structure of Lie groups allows to perform physically correct computer modeling of the dynamics of mechanical systems. Variational integrators on Lie groups have significant computational advantages over classical integration methods, which do not preserve the geometric structure of the continuous system and the basic constant quantities of the system, and other variational integrators, which preserve either none or one of these properties.

Purpose of research. The purpose of this study is to solve the problem of restoring the external load on the rack– and-beam structural system and to assess the impact on the accuracy of solving the problem of the error of noisy deflections – constructive input data of the computing system.

Methods. The main scientific methods used in this study are methods of modeling and identification of boundary conditions, the grid method of regularization of solving inverse incorrect problems. Measurement reduction and approximation methods, methods for evaluating the quality of input data processing, regularization and approximation algorithms using the Lebesgue grid function, and numerical methods are also used.

Results. The main result of this work is two theorems about the external load on a rack-and-beam structural system. The existence and uniqueness of the solution is proved. Also, the results are the formulas of Lagrange multipliers in linear Lagrangian approximation and the optimal plan of coordinates of the nodes of the approximation grid for the equation of deflections of the beam of the fourth and fifth degree with Chebyshev alternance. An assessment of the quality of the approximation of the external load on the rack-and-beam structure by the values of the target parameters was carried out.

Conclusion. This article proposes a method for restoring the external load on a rack-and-beam structure using the results of solving the inverse Cauchy problem for the equation of deflections of a beam with minimizing the influence of the error of noisy input data.