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Creation of new digital technologies let automate the reproduction of text and graphic information, led to the creation and development of the digital printing. Digital printing is a technology for producing prints in the printer based on the original layout, created as corresponding codes with a computer. One of the technologies of digital printing is a computer-to-press and one of the devices in this direction is risograph. The risograph printing quality is worse than offset printing. The text is printing with medium sharpness and images remind photos in old newspapers and require special preparation. But risograph is the most profitable solution for small and medium circulations from 50 up to 1000 sheets. Wide usage of risograph printing in typographies demands increase performance of the equipment with the high print quality of digital images. To improve the quality of risographic printing, the creation of methods is required to form the initial indicators of the original layout (clarity, correct transmission of halftones, contrast). At the same time, the result of obtaining high-quality images obtained by printing on a risograph is affected by surface microgeometry and the physical and mechanical properties of paper. So, the optical density of the ink layer on the print is largely determined by the structure of the sections of paper, in particular, absorbency and porosity. To obtain high-quality images on prints, it is necessary not only to customize the original layout, but also to select paper with such characteristics that would allow you to get the best result when printing on a risograph. Since the risograph occupies an intermediate place in quality between copying equipment and laser printing, a laser print is taken as the standard for print quality. And one of the tasks of the quality of risographic prints is to increase it to the quality of laser printing.

Тhematic Index.

Experimental studies of the dynamics of temperature, transmittance coefficient and forward scatter of radiation in the smoke under the ceiling space when burning paper where conducted. Behavior of main signs of fire at an early stage, common for the mentioned type of inflammables, was studied.

One of the important tasks is to deliver to the consumer a calibrated high-quality metal in a saleable condition, which requires protection from atmospheric corrosion and adverse climatic factors, protection from contamination and mechanical damage for the period of transportation to the consumer by motor transport, and storage at intermediate warehouses before going into production. A comprehensive system approach is needed to preserve the quality and appearance of the products on the way from the manufacturer to the consumer. The use of modern packaging materials, such as paper with corrosion inhibitor and polypropylene fabric reinforcement, will allow to obtain permanent guaranteed protection of the rolled surface and expands the possibilities of transportation and sales markets of metal products. The testing stage of the corrosion inhibitor included the determination of its protective properties. It is established that the advantage of packaging of rolled products in anticorrosive paper is that it, combining the functions of packaging means and means of preservation, allows you to completely abandon the expensive and time-consuming preservation of metal products with oils and greases. The use of a volatile corrosion inhibitor in the composition of the paper provides full protection of rolled products.

The paper gives an assessment of existing casting methods used for manufacturing products from aluminum materials with carbon filling compounds. It presents results of comparative studies of properties of aluminum materials in which microcrystalline graphite, fullerene black, nanotubes and an amorphous phase of glass carbon have been used as filling compounds.

The article presents results of our experiments carried out to study the invariance of the digital description of the image of a handwritten signature presented on paper. The description is built on the basis of a normalized image of the signature, digitized in the visible range of the electromagnetic spectrum by a scanner, with subsequent calculation of the distribution of its local features. The variability of this representation of the signature under different conditions simulating a change in its color, orientation on paper, line thickness and dimensions has been experimentally studied. It is shown that the digital description of the handwritten signature image, previously proposed by the authors, is sufficiently invariant with respect to the listed conditions for its execution to perform the off-line signature verification procedure.

Currently, the topical trend in the development of energy complexes in a number of countries is the expansion of the solid fuel use, which is largely provided by the use of various types of local renewable fuels. The latter often have high thermal properties (heat of combustion, ash content, etc.), but have low or poorly predicted physical and mechanical characteristics (strength, granulometric composition, etc.). These circumstances practically make stable and efficient operation of automation systems, mechanization of transportation of pellets, and technological processes of boilers impossible. The formation of a composite fuel with specified physical and mechanical properties provides a solution to this problem. The structure of the composite fuel based on peat, sawdust, cellulose and modifier was established at the previous stages of our work. However, in case of a given composition, the physical and mechanical characteristics depend on the operating and technological conditions for obtaining granules. In this paper, a statistical and experimental study was carried out aimed at finding rational technological conditions for granulating and drying composite fuel particles with a given mass ratio of components. To prepare fuel pellets of a given size from the initial fine-fraction components, a laboratory installation was used, the main elements of which were a Z-shaped mixer, a screw granulator, and a fixed bed dryer. The influence of independent variables on the strength and final moisture content of finished pellets of composite fuel was determined within the framework of a full factor experiment. The paper presents graphical images of response surfaces characterizing the specified influence of variable factors. The obtained regression dependences describing the influence of factors on the target properties of granules are linear in nature. The latter limits the possibility of using gradient optimization methods and creates the need to search for rational conditions, taking into account the limitations caused by the technical and economic parameters of obtaining finished fuel pellets.

The paper presents a new view of vector physical quantities as multicomponent quantities. Each of the components of the mentioned multicomponent quantities can carry important and even unique information about the sources and causes of their occurrence. Looking at the vector quantity as the multicomponent quantity led to the need to form the corresponding conception. There are three positions of this conception in this paper, which are formulated as follows: vector multicomponent physical quantities are considered as functions of the set of their constituent information components; the communication functions of the specified information components in the models of multicomponent physical quantities are determined by the laws of vector algebra; information models of vector multicomponent physical quantities allow an alternative representation of information components depending on the selected coordinate system.The mathematical model of the vector multicomponent physical quantity is presented. This model is fundamental and directly follows from the positions of the conception formulated above. This model can be applied to describe multicomponent displacements and deformations that both simple and complex objects undergo. An example of the complex object can be the manipulator of the universal industrial robot. The space for modeling multicomponent displacements of simple objects was shown in the paper. Information models of vector multicomponent physical quantities allow one to alternatively represent informative components. And the task of constructing such models is complex and ambiguous. Therefore, the formal apparatus for the synthesis of such models, which is based on certain rules and conventions, was proposed in the paper. The theoretical foundations of the method of optical measurements of informative components of multicomponent displacements and deformations of simple objects, which involves the use of multidimensional test objects, are presented.

Modern development of society and the economy is generally accompanied by abandonment of non-renewable fuels in the system of existing attitudes toward environmental issues and resource conservation. The paper presents the results of complex operational tests of КВм-2.0 water boilers with automatic stoker and КВр-0.4K at heat supply facilities of the Arkhangelsk region under the typical operating conditions on coal, fuel mixtures, and also peat briquettes and sod peat. Experimental work was carried out using modern methods and advanced technical means. Within the framework of the research on the conversion of boilers to peat fuel, balance experiments were carried out; technical, economic and environmental performance indicators were obtained; the selection and analysis of focal residues were carried out, fine solid and soot particles polluted into the environment were studied in detail. The paper presents graphs of changes in gross efficiency, heat loss with exhaust gas, heat loss with incomplete combustion, and concentrations of sulfur and nitrogen oxides during the cycle between loading peat briquettes into the КВр-0.4K boiler, as well as graphs of changes in the heat balance components and gross efficiency all boiler units under investigation. The conversion of heat generating plants to peat fuel combustion makes it possible to achieve a significant reduction in emissions of solid and soot particles without upgrading ash-collecting plants. Complex experimental studies conducted of existing hot water boilers with a nominal heating capacity of 0.4 and 2.0 MW have shown the possibility, as well as the energy-environmental efficiency of burning briquetted and sod peat in the combustion chambers of these heat generating plants.

As in the whole world, there are regions in Russia that experience heat supply difficulties, mainly due to the high cost of fossil fuel as well as to growth of energy resources cost and polluting emissions. In this regard, search for solutions which would provide energy saving with an increase of energy, commercial and ecological efficiency of modern heat supply systems is becoming vitally important today. One of them is the development and use of special types of energy including renewable energy sources, wind energy in particular. Accordingly, the paper presents one of the possible solutions to the heat supply problem which are directed at meeting the whole region’s heat demand through the joint use of wind power plants with a boiler room operating on fuel oil. The study assessed the efficiency of constructing of wind power plants with a total capacity of 1.7 MW for the heat supply needs of a settlement, which is located on the Barents Sea coast in Russia. The selected area is characterized by an average annual wind speed of 7.0 m/s and a long heating period (9–10 months a year). The assessment showed that the wind power plant construction is financially reasonable, as additional profit can be generated by the end of the wind power plants scheduled service life that make up the half of primary investments. The results obtained in the paper are expected to make up for the lack of information on the feasibility of wind power plants construction for the heat supply needs, which is very useful for other countries that have similar areas experiencing various heat supply difficulties.

The paper considers the suppression of chaotic oscillations in small energy systems that occur in emergency modes and lead to the phenomenon of voltage collapse, which corresponds to the process of voltage drop in the network, which can be accompanied by a complete shutdown of the affected area. The paper also presents a method that has been developed and that allows changing the spectrum of Lyapunov’s characteristic indicators and converting chaotic oscillations in a small power system to regular dynamic modes. The method of synthesis of control actions is based on the theorem of topological equivalence of hyperbolic nonlinear systems and their linearized models as well as on and the use of numerical integration of nonlinear differential equations describing the behavior of power systems in order to construct a phase portrait and calculate Lyapunov’s characteristic exponents. The results of the work consist in the synthesis of feedback, which ensures the formation of a spectrum of Lyapunov’s characteristic indicators with negative values. The suppression of chaotic regimes occurs by forming a spectrum of negative Lyapunov’s characteristic indicators in a closed system. The parameters of the regulator in the feedback circuit are determined using the modal control method based on the solution of the matrix algebraic Sylvester equation. The solution of the problem of transition from a chaotic regime to a regular movement in a small power system is considered. To test the operability of the proposed method of chaos suppression, the spectrum of Lyapunov’s characteristic indicators is calculated and trajectories in the phase space of the initial nonlinear system and the system with control action are constructed. For energy systems with chaotic dynamics, synthesized feedback makes it possible to suppress chaotic fluctuations and switch to regular modes, thereby preventing the occurrence of emergency modes.

The Republic of Belarus uses traditional and modern systems of fare payment for public passenger transport. In the traditional system, paper tickets are used as proof of payment; such a system is common in all settlements of the country. Electronic tickets generated in mobile applications of various electronic systems, on physical media – contactless smart cards, as well as records of relevant transactions from bank card accounts are used in modern fare systems to confirm payment for a transport service. Both single trips and multiple travel tickets can be recorded in the form of an electronic ticket or an electronic entry on the contactless smart cards. The paper proposes measures aimed at increasing the level of payback of public passenger transport, analyzes the volume of passenger traffic for 2016–2020, the decisions of local authorities in force in the cities of Belarus that establish regulatory and cost indicators for fares in public passenger transport. The comparison of modern fare payment systems implemented in cities is carried out. TapXphone and T-PAY systems are recommended for distribution on public passenger transport in Belarusian cities on the basis of the comparison of the positive аnd negative aspects of the functioning of electronic fare collection systems from the position of a passenger and a carrier.

The paper presents the technology of multi-component briquetting of solid fuel (MSF-fuel) developed by the authors, which makes it possible to reduce economic losses from the non-use of combustible waste from industrial and municipal human activities. The issues of energy and resource saving, rational use of natural and secondary resources in accordance with the National Strategy for Sustainable Development of the Republic for the period up to 2035 are considered in the paper. The concept, structure and principles of the circular economy are analyzed. The paper provides characteristics of the main areas of use and processing of waste that have not found application in traditional technologies and energy. Some aspects of the conducted research on the production of multicomponent solid fuels are presented in the paper. The technology of briquetting wet mixtures with the addition of various binders, including combustible waste, is described, taking into ac-count the factors that affect the performance of the briquetting plant and the density of the fuel. Various ratios of the components of briquetting fuel have been analyzed and the compositions are determined, at which the best production, consumer and environmental indicators are analyzed. The paper studies the energy and physicochemical characteristics of the produced multicomponent fuel. Algorithms for selecting fuel components have been developed. The results obtained can be used to solve problems of rational use of combustible industrial waste by producing a multicomponent solid fuel that meets the established energy and environmental requirements.

The proposed paper is a continuation of the author's theoretical work presented earlier in the development of the theory and methodology for calculating flexible orthotropic reinforced concrete plates on an elastic foundation, taking into account the physical nonlinearity of the plate material. The paper presents numerical results of elastic and nonlinear calculations of an isolated rectangular orthotropic plate on an elastic foundation, modeled by an elastic homogeneous isotropic layer rigidly connected to a non-deformable foundation under the action of an external static load, taking into account the own weight of the reinforced concrete plate. The change in its stiffness at the time of cracking and further active opening of cracks has been taken into account in the calculation of the structure under study. The nonlinear calculation of the studied structure takes into account the change in its rigidity at the time of cracking and further active crack opening. The calculation of a flexible orthotropic plate on an elastic foundation in a nonlinear formulation is performed iteratively by the method of B. N. Zhemochkin. A mixed method of structural mechanics has been used to determine the coefficients of canonical equations and free terms. At the first iteration, the reinforced concrete plate is calculated as linearly elastic, homogeneous, and orthotropic; at the subsequent ones – as linearly elastic, inhomogeneous, and orthotropic at each Zhemochkin site. Camber plates with a clamped normal in the primary system of mixed method due to the action of a concentrated force are determined by the Ritz method when the deflections were represented as a power polynomial in a new original expression that has been proposed for the first time in the Part 1 of the paper. The solution algorithm has been implemented using the Wolfram Mathematica 11.3 computer program. Numerical and graphical results of elastic and non-linear calculations of sediment concrete road plate, contact stresses and bending moment diagrams on the plate are presented in the paper.

The allocation of experts to programmer teams, which meet constraints on professional competences related to programming technologies, languages and tools an IT project specifies is a hard combinatorial problem. This paper solves the problem of forming the maximum number of teams whose experts meet all the constraints within each team. It develops and compares two algorithms: a heuristic greedy and exact optimal. The greedy algorithm iteratively solves the set cover problem on a matrix of expert competences until can create the next workable team of remaining experts. The paper proves that the allocation greedy algorithm is not accurate even if the set cover algorithm is exact. We call the allocation algorithm as double greedy if the set cover algorithm is greedy. The exact algorithm we propose finds optimal solution in three steps: generating a set of all non-redundant teams, producing a graph of team’s independency, and searching for a maximum clique in the graph. The algorithm of generating the non-redundant teams traverses a search tree constructed in such a way as to guarantee the creation of all non-redundant teams and absorbing all redundant teams. The edges of the non-redundant team independency graph connect teams that have no common expert. The maximum clique search algorithm we propose accounts for the problem and graph features. Experimental results show that the exact algorithm is a reference one, and the double-greedy algorithm is very fast and can yield suboptimal solutions for large-size allocation problems.

The paper considers an issue of international logistics development in Belarus under world coronavirus COVID-19 pandemic. As a result of analytical reviewing of the up-to-date scientific literature on the problem under study, the expediency is stated for highlighting the logistics of international road freight transportation as an independent area of theoretical research and practical activity. Further development of international road freight transportation logistics in the Republic of Belarus requires a complex economic analysis of the present state and dynamics of the international road freight transportation market, which is the main purpose of the present publication. The paper contains the results of the analysis of the market for international and transit freight road transportation. Separately the paper points out the dynamics of transit goods transportation segment in this market in response to the reorientation of international freight flows. Interconnection is shown between the volume indices of international road freight transit through the territory of Belarus and the dynamics of goods import to the Russian Federation from the EU countries. For the first time a proposal is given to use the methodological tools of systemmatrix diagnostic analysis for investigation of the macroeconomic development process of international road freight transit logistics. The author’s set of initial parameters for the analysis has been formed, and its results are presented on the basis of the data of the State statistical reporting form for 2019–2020. A suggestion is given for joint usage of system-matrix diagnostic tools in combination with author’s methodology for assessing the effectiveness of transit (international) freight transportation while evaluating the competitiveness of economic entities in the industry. The most typical trends of the market development in the short term are stated, taking into account the more complicated market conditions.

Previously, the author obtained an analytical solution for determining the vertical displacements of the homogeneous isotropic quarter-space face, which is affected by a vertical concentrated force. This expression gave an exact solution for determining the vertical displacements of a quarter-space face made of incompressible material and an approximate solution for a Poisson ratio different from 0.5. Later, in the published paper by S. V. Bosakov and P. D. Skachek “Action of Concentrated Force on 1/8 of Homogeneous Isotropic Space”, it was shown that by combining solutions for determining the vertical displacements of a quarter-space and a half-space from the action of concentrated forces, one can find vertical displacements for one-eighth face of a homogeneous isotropic space. The resulting expressions allow solving contact problems for non-classical domains in the form of a quarter of a space and one eighth of a space. Below, the author obtains the first approximation for displacements of a quarter-space face from the action of a vertical concentrated force. In this paper, the author gives the first approximation for determining the vertical displacements of a quarter-space face from the action of a vertical concentrated force, widely using the special approximation method developed in the works of V. M. Alexandrov and allowing to calculate successfully improper integrals. The constructed graphs show good results when determining displacements with a Poisson’s ratio different from 0.5 and equal to 0.5. It should be noted that the approach indicated in the paper by S. V. Bosakov and P. D. Skachek can be successfully used in determining all displacements of the faces of one-eighth face of a homogeneous isotropic sharpened forces tangent to the edge of a quarter-space and this will allow to solve contact problems taking into account friction forces in the contact zone of the beam or plate.

Internet marketing in the industrial market has a number of features and differs from that in the consumer market. The first is characterized by specialized and personalized approaches, as well as it must take into account the long cycle of the transaction, and the presence of a large number of decision makers. Marketers at industrial enterprises must have a range of knowledge about the market and industry trends, possess information about the organization of procurement processes and the operation of distribution channels, and be able to build a communication process with a certain type of customer. The paper presents methods for online promotion of industrial products and a study of the features of choosing of internet marketing tools for industrial enterprises. The main idea of the paper is to highlight the expert component for such enterprises as the main tool for communication with customers. To solve this problem, the internet marketing tools of an industrial enterprise has been considered and the expert component in its content strategy has been shown, approaches to the systematization of internet marketing tools have been studied. In the course of the study, general scientific methods have been used: analysis, synthesis, generalization. The result of the research is a model of product promotion in the logic of the industrial consumer's journey, which is based on the connection of the consumer's journey map with internet marketing tools.

An analysis of the probability and conditions for the occurrence of soil liquefaction at the base and in the vicinity of hydraulic structures is presented in the paper. As a rule, hydraulic structures are erected in the valleys of watercourses, the structure of the soil in which contributes to the occurrence of liquefaction processes. These soils are fine-grained, non-cohesive, usually consisting of fine- and medium-grained or silty sands, sandy loams, interspersed with layers of loams. Massifs under pressure hydraulic structures are quite water-saturated. Soil liquefaction occurs as a result of the destruction of structural bonds between particles in water-saturated dispersed soils under the action of stresses of various types. An external dynamic or static load applied to a water-saturated massif composed of weak, finely dispersed soils can lead to a complete or partial loss of soil bearing capacity and its transition to a fluid state. The magnitude of soil resistance to shear is determined by the degree of its water saturation; at a moisture content of about 20 %, the angle of repose of sandy soils is significantly reduced. The restoration of the strength properties of soils is prevented by the pore water pressure, the process of compaction (consolidation) of the soil mass occurs after the water is squeezed out of the pores, the flow time of which depends on the filtration properties of the massif. Liquefaction of soils leads to a disruption in the normal functioning of a hydraulic structure, the creation of emergency situations. The paper provides examples of accidents at hydraulic structures in Russia caused by liquefaction phenomena. It is noted that the main directions of protecting the structures of hydraulic structures from dangerous liquefaction are to prevent the possibility of liquefaction and the reduction of its harmful effects. In this regard, several methods are considered – compaction and strengthening of soils at the base of structures; filtering surcharge device using geotextiles and geogrids; creation of an effective drainage system.

The paper studies the issue of improving the evenness of the prefabricated concrete pavement by changing the design of the slabs from which it is assembled. Irregularities of the prefabricated pavement mainly occur at the junction of the plates and are called “keyboard” effect. The reason for the unevenness is the vertical movement of the ends of the plates relative to each other when the car passes. In order to correct this situation, the authors propose to arrange transverse ribs of rectangular cross section at the ends of the plates. Such ribs will create a reliable support at the edges of the slab, which will reduce the vertical movement of its ends. To determine the effectiveness of the use of transverse ribs, a concrete slab with dimensions of 3´6 m has been examined in the paper. The transverse rib in cross section had the shape of a rectangle with sides 20´10 cm. In order to compare the test results, a concrete slab of the same dimensions, but without transverse ribs, has been studied. Deformations and stresses of the slab under load have been determined by the finite element method using the Lira software package. Calculations have shown the effectiveness of the slabs with transverse ribs mounted on its edges. The vertical displacements of the ends of the slabs with ribs are two times less than those of the slabs without ribs, and the stresses are 2.4 times less. It is obvious that the use of concrete slabs with transverse ribs at the ends will reduce the unevenness of the prefabricated coating at the points of their mating.

The paper presents studies on saving energy resources by creating conditions and introducing modern energy-efficient technologies and equipment into production activities that allow to develop the production and use of local fuels, including the use of briquetting of combustible municipal and industrial waste. The purpose and objectives of the work are to study trends and analyze the problems associated with the processing and use of various types of combustible waste generated and accumulated in industrial and agricultural enterprises, as well as in the field of housing and communal services. The main directions of national sustainable development strategy concerning energy and resource saving and rational use of natural and secondary resources are considered in the paper. Methods for briquetting multicomponent compositions of combustible wastes with the possibility of obtaining solid fuels have been studied. An innovative production technology developed by the authors is described that makes it possible to process waste products by briquetting with the use of various binders. The results are presented and the analysis of the conducted experimental studies is carried out in accordance with the theory of experiment planning for multicomponent systems, taking into account phase equilibria. A qualitative assessment of the component composition of the briquetted fuel, which ensures the highest density of the briquette and effective performance, is carried out taking into account of the moisture content of the multicomponent mixture. Qualitative indicators of the produced two- and three-component fuels have been determined using differential thermal analysis on the MOM-1500 derivatograph, which make it possible to identify phase transformations and chemical reactions occurring during heating. Comparative analysis of qualitative indicators has permitted to draw conclusions about the possibility of using the developed fuel compositions in operated fuel combustion plants.

The main directions of the concept of national strategies for sustainable development are considered, taking into account the problems of energy and resource saving, as well as the need for the rational use of natural and secondary resources in many countries of the world community in order to transition to a “green” economy. An assessment of the energy potential of combustible waste that has not found technological application is given as one of the priority areas in the field of nontraditional energy. The paper presents aspects of research into obtaining and production of multicomponent solid fuels. A technology is described for briquetting wet mixtures with the addition of various binders, including various combustible wastes, in order to obtain solid fuel. The features of the fuel frame formation are given, taking into account the factors affecting the performance of the briquetting plant, as well as achieving the optimal density of the briquette. A qualitative assessment was made with respect to various ratios of the components of briquetted fuel, at which the best production and consumer indicators are achieved. The features of the preparation of materials and the technological equipment used as part of the preparation and briquetting line are considered. The practical aspects of the production, drying, use of briquetted solid fuels are outlined in the paper. The paper presents studies of the energy and physico-chemical characteristics of multicomponent fuel compositions using various research laboratory equipment and methods. The proposed algorithm for solving the problem makes it possible to rationally use substandard combustible production waste to obtain multicomponent solid fuel, while energy and environmental aspects are taken into consideration at the production stage.

The development of research in the field of creating a mobile monitoring system for diagnosing the technical condition of mining equipment in terms of mechanical vibration parameters is one of the most science-intensive areas. The paper presents the results of investigations on the possibility of isolating the mechanical vibrations of the handles with a natural frequency of 5 Hz, which occur with a greater or lesser amplitude in almost all registered spectra, arising from breakages of cutters on the cutting discs of double-flow drives of the executive body of a mining machine. Therefore, it can be used for operational mobile monitoring of breakages in the cutters of the executive bodies of mining machines. An analysis of vibrations has confirmed the fact that they are transmitted to almost all non-rotating parts of the combine, where they can be registered, which allows them to be used for mobile automated monitoring of cutter breakages on cutting discs. On the example of the combine “Universal-600” it has been found that the most convenient when registering these vibrations from the standpoint of the absence of the need to introduce a signal transmission module from the rotating parts of the combine into the measuring path can be considered the placement of a vibration sensor on the body of the input gearbox of the executive body drive with its orientation in the direction combine movements, where oscillations with a frequency of 5 Hz are prevalent and it is quite simple to isolate them from the low-frequency range using standardized low-frequency one-third octave filters. The paper proposes a technique for creating a system for automated mobile monitoring of cutter breakages based on the parameters of mechanical vibrations of cutting discs with natural frequency.

By usage of the technical and economic calculation method developed by the authors for installations with recuperative-type heat exchangers, the operational modes of the centralized supply and exhaust system of organized ventilation, in which the supplying air is heated by the solar radiation heat and the heat of the air removed from the premises, have been investigated in the paper. The paper presents results of the thermal and economic efficiency assessment of such ventilation system for multi-storey buildings. A comparison of the thermal energy consumption for the needs of heating and ventilation through the use of the proposed ventilation system has been made for two variants of buildings – with the thermal protection level of enclosing structures that meets modern regulatory requirements (buildings with heat consumption up to 130 kW×h/(m2×year)), and for a building similar in terms of planning structure, but with enclosing structures, the insulation level of which corresponds to buildings built before 1993 (buildings with heat consumption up to 260 kW×h/(m2×year)). The temperature conditions have been determined under which it becomes necessary to turn on the operation of devices for additional (peak) heating of the supply air, when the thermal potential of solar radiation and secondary energy resources is insufficient to provide the calculated temperature of the supply air. For the ventilation system under consideration, it has been established that the thermal resistance of the building envelope influences the indicators of the thermodynamic and economic efficiency of the proposed solution. The climatic conditions under which the utilization of the exhaust air heat in the proposed ventilation system is technically justified and economically expedient have been determined. The results of the research

The paper considers the influence of the parameters of the plasma spraying process on the technological characteristics of multilayer coatings based on nickel-chromium, nickel-chromium-aluminum-yttrium materials, oxide ceramics, intended for operation at high temperature and additional dynamic loads. The design of plasma coatings during their application (with subsequent high-energy processing) under such conditions requires a comprehensive solution – both the use of high-quality powder ingredients and the optimization of technological parameters. The plasma process of applying powder materials has been improved to obtain the maximum values of their utilization factors. The technological characteristics that affect the properties of plasma coatings are optimized, namely: the flow rates of the plasma-forming and materials-transporting gases, the flow rate of supplied powder materials, the current and voltage of the electric arc of the plasma torch, the distance from the plasma torch nozzle exit to the substrate. The paper presents the results of studies of the structure of coatings, performed using scanning electron microscopy. Their analysis has made it possible to form general regularities obtained by the action of radiation of compression plasma flows on coatings formed by air plasma. The considered structures are created using the processes of melting, compaction and high-speed cooling of plasma coatings. The main optimization indicators are the maximum local compaction and spillage of the obtained compositions with the absence of defects and destruction from the impact of compression plasma flows. The main effect during the action of radiation of a compression plasma flow on previously formed coatings is thermal. It contributes heating of the near-surface layer. When the coating is exposed to radiation of compression plasma flows, a remelted layer of oxides with a thickness of about 12–15 µm is created, smoothing the relief of the formed surface and creating a network of cracks on the surface, diverging into the depth of the coating. The liquid-phase processes occurring in the molten phase of the near-surface layers after exposure to compression plasma radiation change the structure of the layers and contribute to the modification of their mechanical properties. By smoothing the surface, increasing the density of the surface crystallized layer and minimizing macro-defects – pores or macrocracks – the mechanical characteristics of the coatings increase.

To analyze the synchronization of machine-building production processes, a statistical approach is used on the correctness of the choice of parameters. The accuracy of the parameters is achieved by modeling. This method allows checking how correctly the parameters are selected and whether they ensure uninterrupted operation of production. Statistical analysis of parameters gives information on failures in a particular production unit, on violations of the synchronization of production processes, technological processes. With the help of statistical characteristics, it is possible to evaluate production as a whole. Statistical multidimensional analysis of complex production data allows to analyze the work of individual units, production blocks. The cluster analysis has been carried out by the method of K-medium production process with minimization of the total error probability. A geometric interpretation of the results of cluster analysis of production processes is given in the paper. The influence of factors on the work of production has been determined in the paper. The index factorial method with a different comparison base and different weights has been applied. The hypothesis about the adequacy of the model of production processes has been tested. A statistical analysis of the complex data of the production process has been carried out in the search for optimal solutions in the case of uncertainty and in conditions of risk using the following methods: Bayes, Laplace and Germeyer using the simplex method. The network methods of decision-making have been used in the paper. Statistical methods with the help of mathematical modeling have substantiated the optimal sizes of both individual parts and volumes of local warehouses, so that there were no delays in the transfer of production processes, disruptions in work, downtime of working equipment. In this case, the criterion for the optimality of production volumes can be the minimum of total losses from idle time of individual units and production blocks to the possibility of disruption of the synchronous process modes due to lack of equipment (arising production pockets) or due to long-used outdated units.

The paper considers options for reducing environmental losses in Polotsk and Novopolotsk through the development of trolleybus and tram systems – various types of urban electric transport. In order to reduce the costs of creating transport (including charging) infrastructure, as well as operating costs, the effectiveness of such systems has been determined when using not only classic types of transport, but also hybrid buses, electric buses, duo-buses. Approaches and methods have been developed to improve the quality of passenger service without deteriorating the environmental situation – this will become possible thanks to the development of tram and trolleybus traffic in Polotsk and Novopolotsk. Variants of scenarios for the use of various types of urban eclectic transport in the cities under study are presented, which will reduce investment in vehicles and the cost of creating an operational base at the expense of existing production facilities, for example, a tram fleet. In addition, this will make it possible to create and organize a unique agglomeration rail passenger system, which can become one of the ways to develop the tourist potential of Polotsk and Novopolotsk. The proposals outlined in the paper are aimed at improving the environmental situation in these cities by reducing the volume of emissions of harmful substances by buses, especially on the central streets.

The regional cluster of renewable energy sources (RES) is an industrial cluster and has the characteristics of the energy industry. Therefore, it needs its own mechanism and structure of formation to ensure integrated development. The paper examines the structure of the regional RES cluster for Vietnam and proposes an apparatus for managing it. Taking into account the experience of other countries, the formation of the structure of the regional RES cluster for the conditions of Vietnam has been substantiated in order to ensure the socio-economic development of the country and its energy system,built and analyzed in accordance with the actual conditions for the use of renewable energy sources in Vietnam and includes five components: profile and non-profile members of the cluster, suppliers, consumers, competitors. A diagram describing the structure of the cluster is illustrated in detail, the roles of the participants are presented. The organizational and management structures of the regional cluster, which correspond to the specific conditions of Vietnam are considered in the paper. The management structure of the Vietnam regional cluster consists of a senior steering committee, facilitator, project manager and working groups. The responsibilities of the participants in the organizational structure are formulated in such a way as to reflect their role in the work of the regional renewable energy cluster. The structure of a regional RES cluster is able to show the relationship between participants inside and outside of the cluster. The organizational structure of the regional cluster and the strategy for its development are the foundations for building a policy in the field of renewable energy sources in the country.

The paper proposes a method for determining a vehicle stopping distance based on a braking rate and a coefficient of using an adhesion force by an automated control system for regulating a braking force on the example of a multi-axle vehicle. The aim of the study is to calculate parameters of the braking efficiency of a multi-axle wheeled vehicle equipped with an automated braking force control system based on the adhesion between a tire and a supporting surface. A peculiarity of the considered method is the use of the calculated braking coefficient of the vehicle and the coefficient of use of adhesion forces during the operation of automated system for regulating the braking force. The presence of new mathematical relationships between the position of the coordinate of the vehicle’s gravity center, realized by the clutches of its wheels, and the braking coefficient of the vehicle makes it possible to simulate the change in the deceleration of a wheeled vehicle in various braking modes of its motion. The terms describing the interaction of an elastic tire with a supporting surface in the braking mode of a wheeled vehicle have been substantiated. Equations are written that permit to calculate: a position of the coordinate of gravity center of a multi-axle wheeled vehicle relative to its front and rear axles; a braking coefficient value of a multi-axle wheeled vehicle based on the coordinates of the position of its gravity center, clutches that are realized between its tires and a supporting surface; load distribution between the respective front and rear axles of the vehicle. To calculate the stopping distance of a wheeled vehicle, it is proposed to take a coefficient value of use of the adhesion force equal to 0.83, regardless of the change in weather and climatic conditions in which the vehicle is operated (a calculation error under an accepted assumption is not more than 5 %). In a graphical form, a design diagram of the coordinate position of a gravity center of a multi-axle wheeled vehicle is presented, which gives a general idea about the redistribution of masses between front and rear axles of the vehicle. Scientific publications on the change in the value of the realized adhesion between the tire and the supporting surface in the braking mode of the automobile wheel under various factors have been analyzed in the paper. The proposed concept for determining parameters of the braking efficiency of a multi-axle wheeled vehicle clarifies some provisions in the theory of vehicle motion, in particular, it allows to apply the calculated method for determining the deceleration of a vehicle in the problem of increasing vertical loads on the axles of a multi-axle wheeled vehicle in the braking mode. The given method for calculating coefficients of weight distribution between adjacent front or rear axles of a multi-axle wheeled vehicle increases an accuracy of determining the amount of deceleration of the vehicle by the calculation method.

The paper presents the main hypotheses of frost destruction of cement concrete. The influence of cyclic temperature changes and the effect of static and dynamic (shock) loads on concrete on changes in the structure and strength of concreteis considered. The paper provides results of comparative tests of frost resistance of concrete containing a porous additive and a plasticizer, which contribute to an increase in the density and impermeability of its structure. It has been shown experimentally that the introduction of air-entraining additives with an additional effect of hydrophobization is productive from the standpoint of ensuring frost resistance of concrete of relatively low classes (up to C30/37), compressive strength up to 50 MPa and water absorption by mass more than 4.0 %. It is advisable to increase the frost resistance of concrete with greater impermeability and strength by increasing these indicators, in particular, due to the maximum decrease in the initial water content and high-quality compaction. This conclusion is experimentally confirmed by the data presented in the paper, since the “mechanism” of frost destruction of cement concrete is multifactorial, and the growth of its density (impermeability) and strength provide a higher ability to resist “force” effects associated with repeated alternating deformations of concrete, as well as the action of external loads, accumulation of fatigue phenomena, hydrodynamics of liquid filtration under the influence of changing temperature fields, etc. A comparative assessment of concrete frost resistance has been carried out using standardized and patented techniques containing a porous (air-entraining) additive, as well as plasticizing and mineral additives of amorphous micro-silica, introduced into concrete in order to increase its density, impermeability and strength and on this basis – increasing frost resistance. Experimental data are presented, reflecting the relationship and patterns of decrease in frost resistance of concrete subjected to the simultaneous action of static (for compression – different levels from the corresponding indicator of concrete strength) and shock, concentratedly applied dynamic loads. The regularity of the relationship between the accelerated frost destruction of concrete and the action of mechanical loads that cause cracking in its structure has been confirmed.

Vibromonitoring is the most methodologically developed and technically equipped with recording tools and data processing approach. However, in the sources of scientific and technical information about mining it is presented much less than other monitoring methods. One of the promising ways to solve this problem, in particular monitoring the breakage of cutting disc cutters of an executive body, is to use parameters of natural oscillations of the parts of gearboxes that occur during impulse loading due to such breakages. It should be noted that in the technically complex equipment of the mining industry, in particular in mining machines, there are many sources of vibration, the vibtaions of which are superimposed on each other. And it is not always possible to isolate and identify the required informative signal with the source. With this in mind the paper presents a research methodology on the possibility of monitoring the breakage of the executive body cutters on the example of the continuous miner “Universal 600” according to the parameters of natural vibrations of the executive body cutting discs arising from the breakage of the cutters. The place of registration of these vibrations is determined – the gearbox handles, on the output shafts of which cutting discs are placed. The frequency of such vibrations is set equal to ~5 Hz. The possibility of using the AGAT-M vibration analyzer with M/AC102-1A vibration sensors as a means of further research has been substantiated in the paper. The paper considers an option of placing vibration sensors on non-rotating gear housings of the executive body drive. An algorithm for recording vibration parameters has been developed, which makes it possible to separate its sources.

The paper describes a technique for modelling and optimization of ring-shaped compound ultrasonic waveguides consisting of two sequentially joined segments of different materials by means of finite elements method. The possibility of using such waveguides for amplifying vibrations in amplitude has been justified in the paper. The advantage of the developed technique consists in possibility of its realization by means of standard engineering software, particularly COMSOL Multiphysics. The correctness and efficiency of the technique is proved by comparing the numerical data with the simulation results by means of transfer matrix method using equations of vibration of Euler – Bernoulli and Timoshenko type. It is shown that in compound ring-shaped waveguides two kinds of vibration modes are possible – variable-sign and constant-sign, moreover only constant-sign modes are of practical interest for amplification of vibration amplitude. Recommendations for selection of optimal geometric parameters of the waveguides are given, particularly it is shown that for ensuring maximum vibration amplification factor it is necessary to choose central angles of the waveguide segments with account for calculated dependence between amplification factor and angle, characterized by presence of several local maxima of the amplification factor. It is noted that the high accuracy of the existing semi-analytical methods for calculating and designing ring-shaped waveguides is achieved using methods based on the application of Timoshenko-type equations of vibration.

Results of a study of an actual scientific and technical problem of determining the road safety level on road sections are presented in the paper. The aim of the study is to develop an express method for assessing road safety based on improving the method of the final accident rate by reducing the partial accident rate with the required accuracy of determining the safety level on public roads. The formalization of the relationship between the parameters of road traffic conditions has been carried out to study the level of safety on highways. Latent factors of the parameters of traffic conditions have been obtained on the basis of reduction of their aggregate by the method of principal components, taking into account the relationship of partial accident rates. This condition has allowed to develop analytical models for determining road safety for implementation in the practice of conducting a road safety audit. A method for identifying hazardous areas on highways has been proposed in the paper. It includes 11 parameters of road conditions out of 18 partial accident rates proposed in the prototype and regulatory documents of Ukraine. The adequacy of the model is determined by deviation values of the obtained data according to the prototype model from the values of the relative accident rate, which were 3.22 and 18.61, respectively. The proposed model reduces the deviation value by six times and affects the accuracy of determining the safety level. Experimental studies have been conducted on 79 km of highways (on 385 sectors with constant values of traffic conditions parameters). The results of a comparative analysis of the safety level for the prototype model and the developed model have been identical and shown a decrease in time and labor costs by 1.6 times without loss of accuracy. Thus, the developed methodology is recommended to be applied for determining the potential danger of road sections during an express analysis of the road safety or when conducting a safety audit at various stages of the road life cycle.

The paper is devoted to the development of methodological foundations for the application of virtual reality technologies (VR-technologies) at various stages of car design and their promotion on the market, in particular, when performing design, prototyping, development of educational and advertising products. The paper analyzes the main areas of application of virtual reality technologies in industrial design in mechanical engineering. An overview of the parameters of the specialized software Unreal Engine 4 and the HTC Vive hardware set used to create and demonstrate virtual projects is performed. System requirements for computer software and hardware for creating virtual projects have been formed. A generalization of our own experience of using virtual reality technologies in the design of an electric vehicle with a frame-panel structure is carried out. The technique of using virtual reality tools in order to create virtual projects for demonstration of design solutions and functionality of mechanical engineering products is described. The issues of choosing software and hardware, their characteristics are considered, as well as a description of the stages of creating a virtual project is given. The process of developing a virtual project is divided into the stages of preparing and transforming a three-dimensional computer model of the demonstrated product into its virtual digital prototype, creating a virtual environment for it, assigning materials and textures with the necessary properties to the environment and the object, setting lighting, navigation parameters and animated actions, optimizing the display of shadows and finalizing the project. The main results of approbation of the developed methodology are presented on the example of creating virtual projects for demonstrating an electric vehicle: in an urban virtual environment and in a virtual pavilion.

. It is known that at present, methods of thermal spraying are widely used to restore and strengthen various worn-out machine parts. As a rule, metal coatings applied by thermal spraying have lower strength characteristics than solid materials. It is believed that the strength of coatings is proportional to their adhesive and cohesive strength. The value of adhesive and cohesive strength depends on various factors, including the nature of the materials and the technology of coating. An important factor characterizing the possibility of using metal coatings in various industries is the strength of adhesion of coatings to the base metal. The paper presents the determination of the adhesive and cohesive strength of coatings from different materials, applied by the method of hypersonic metallization. The results of testing the strength of metal coatings made of ER316LSi-grade wire, nichrome (Cr20Ni80) and molybdenum wire are given in the paper. Based on the results of metallographic studies, the proportion of the participation of cohesive and adhesive components in the strength of coatings has been determined, and some features of coating destruction have been described. It has been found that the participation of the cohesive and adhesive components of the coating strength differs depending on the material used. The cohesive component prevails in the strength of coatings made of high-alloy wire of the ER316LSi-grade, at which destruction mainly occurs along the coating-base boundary. For nichrome coatings and especially for coatings made of molybdenum, the cohesive component is predominant, in which the destruction of the coating occurs not along the coating-base boundary, but between the coating layers.

Block symmetric ciphers are one of the most important components of modern information security systems. At the same time, in addition to the structure of the applied block symmetric cipher, the cryptographic strength and performance of the information protection system is largely determined by the applied encryption mode. In addition to high performance and high-quality destruction of block statistics, modern encryption modes should also protect encrypted information from occurred or intentionally introduced errors. In this paper, we have developed an encryption mode with blocks skipping and using a pseudo-random key sequence generator, which allows checking the integrity of encrypted information with accurate detection of the place where an error was introduced. In this case, the error detection accuracy is determined by the adjustable parameter of the macroblock size and can be set depending on the level of importance of the protected information. The developed encryption mode is characterized by the following key advantages: reducing the number of required encryption operations by half, while providing a high level of cryptographic quality; more effective destruction of macroblock statistics due to the use of an additional generator of pseudo-random key sequences, the impossibility of propagation of the occurred (intentionally introduced) error outside the macroblock, as well as higher values of the number of protection levels due to the possibility of classifying the initial states of the applied generators of pseudo-random key sequences. As proposed in this paper, the mode of authenticated encryption with blocks skipping can be recommended for use on mobile platforms that are demanding both in terms of the quality and reliability of the protected information and are limited in terms of computing and power resources.

This paper is devoted to the reduction of data transfer between the main memory and direct mapped cache for blocked shortest paths algorithms (BSPA), which represent data by a D[M×M] matrix of blocks. For large graphs, the cache size S = δ×M2, δ < 1 is smaller than the matrix size. The cache assigns a group of main memory blocks to a single cache block. BSPA performs multiple recalculations of a block over one or two other blocks and may access up to three blocks simultaneously. If the blocks are assigned to the same cache block, conflicts occur among the blocks, which imply active transfer of data between memory levels. The distribution of blocks on groups and the block conflict count strongly depends on the allocation and ordering of the matrix blocks in main memory. To solve the problem of optimal block allocation, the paper introduces a block conflict weighted graph and recognizes two cases of block mapping: non-conflict and minimum-conflict. In first case, it formulates an equitable color-class-size constrained coloring problem on the conflict graph and solves it by developing deterministic and random algorithms. In second case, the paper formulates a problem of weighted defective color-count constrained coloring of the conflict graph and solves it by developing a random algorithm. Experimental results show that the equitable random algorithm provides an upper bound of the cache size that is very close to the lower bound estimated over the size of a complete subgraph, and show that a non-conflict matrix allocation is possible at δ = 0.5 for M = 4 and at δ = 0.1 for M = 20. For a low cache size, the weighted defective algorithm gives the number of remaining conflicts that is up to 8.8 times less than the original BSPA gives. The proposed model and algorithms are applicable to set-associative cache as well.

The paper deals with the problem of improving the reliability of DC-DC power supplies with pulse-width modulation. The topicality of the work is related to the importance of power supply issues in modern electronics, since the quality of operation of consumer electrical appliances, including critical ones, directly depends on the serviceability of sources. The object of the study is feedback circuits aimed at stabilization of the parameters of power supply of consumers. Failures of the mentioned feedback circuits most often occurs due to the electronic components degradation under harsh operating conditions as well as under severe mechanical overloads. Such failures are dangerous for uncontrolled increase of power supply output voltage and output current. To avoid this, a new method of reserving voltage feedback signals is presented in the paper which is implemented on the basis of flyback supply topology. Feedback signals are formed from the optocoupler located on the load side and from the auxiliary winding of the power transformer, together forming two independent output voltage control circuits. Only one circuit performs stabilization at any given moment of time. If one of these circuits fails, the second one can simply replace it in its operation. The proposed method does not require any digital signal processing algorithms or microprocessor control modules and can be implemented on the basis of cheap, widely available analog chips that perform pulse-width control of the output voltage. As a result, the problem of sudden feedback loop failure is solved and the reliability of electrical equipment is increased. The validity of the proposed method is confirmed by the results of computer simulation with the use of MatLab-Simulink environment. The obtained results can be used in design of fault-tolerant secondary power supplies that operate in harsh operating conditions.

The paper deals with the problem of increasing the efficiency of the functioning of electric networks up to 1 kV, namely, the possibility of increasing the sensitivity of protections in networks up to 1 kV, which helps to reduce the protection response currents and, accordingly, reduce the cross-section of cable and wire products. The topicality of this problem is shown and the research tasks are defined. Much attention is paid to the concept of selectivity; attention is also paid to the concepts of full and partial selectivity. “Which protective devices can be considered selective?” is a question that is considered and worked out in sufficient depth in the paper. The negative phenomena that occur when ensuring the selectivity of protections in networks up to 1 kV are systematized and described in detail. Based on a comparative analysis of the parameters of circuit breakers with release tripping devices of various types, a solution to this problem is proposed by using circuit breakers with microprocessor and semiconductor release tripping devices. Additional advantages of microprocessor-based circuit breakers are considered and indicated, as well as their disadvantages are indicated, too. The main expected positive effects from the use of circuit breakers with microprocessor release tripping devices are listed, taking into account the fact that this type of circuit breakers is considered as a complex of devices replaced by it. The article can be recommended to employees of electric power specialties working with networks up to 1 kV.