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The widespread use of risograph printing in printing houses requires an increase in the speed of equipment while maintaining the printing quality of the original layouts. The problem of risograph printing is not always obtaining high-quality images, since the risographs used in the standard driver (periodic, non-periodic) do not always allow you to get the printed image the same as in the original. This is reflected in the insufficiency of parameters such as image clarity and sharpness. Problems of poor quality of risograph printing can be solved by changing the settings of the risograph driver for the original layout with additional use of digital filtering and image rasterization. This will require the creation of additional image rasterization methods to improve the initial indicators of the original layout in contrast, clarity, and the correctness of the transmission of halftone images and will improve the quality of printed images, as well as ensure the efficiency of the printing process for a wide range of original layouts.

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.

I. Тhematic index II. Name index

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 considers problems pertaining to methodology and structure for dissertation preparation. All the problems have been solved on the basis of the analysis of questionnaire complexes. The paper presents concrete examples taken from the dissertations that have passed expertise of the Highest Certifying Commission.

A method has been developed to improve paper qualitative characteristics which is used for manufacturing of packaging. It has been determined that while adding sulfate cellulose obtained from low-grade short flax in paper composition qualitative characteristics of the final product have been improved.

Hydraulic investigations of the Dneeper water intake for Newsprint Paper Mill in Shklov under various water levels and discharge in the river have been carried out. Regimes of bed alluvium and sludge motions have been studied. The recommendations on intake channel scheme and its main dimensions are given.

The paper investigates an influence of component quantity (lignin, cellulose and hemicellulose) on qualitative (physical and mechanical) indices of waste-paper in relation to its storage period and weather conditions. It has been established that while storing (in waste dumps) waste paper it is to be kept at a definite temperature and humidity in order to reduce impact of weather conditions.

The first part of paper deals with the base information about diagnostics of power transformers. In this part are presented differently insulating methods, for example method of recovery voltage method, method of polarization and depolarization currents and chromatographic analysis.The second part of paper deals use of method of frequency domain spectroscopy for oil power transformers. This method is used in analysis insulating condition of power transformer with system of oil-paper. It was found, that the results of these tests are highly impacted by the operating temperature during the experimental measurement. Moisture and conductivity between insulating paper and oil in an insulating system are highly dependent from temperature.In the other part, the paper presents experimental results of the frequency diagnostic measurement for a real single-phase traction transformer 110/27 kV at different operating temperatures and states (with oil and without).Finally in the last part, the paper presents comparing frequency insulating measurements among several the same single-phase transformers 110/27 kV.

The thermal impact of cable power lines and structural materials of cables on the environment has been considered. A quantitative evaluation of the thermal impact of electrical cables with cross-linked polyethylene insulation on the environment was carried out using the Elcut program. Analysis of the temperature field near the loaded cable line of 10 kV demonstrated high values of soil temperature that negatively affects its redox potential and living organisms. To evaluate the environmental impact of electrical cable materials, an approach has been developed that takes into account not only the toxicity of the materials but also their volumetric content in the cable. Cable lines with cables with traditional paper-oil insulation cause more damage to the environment than cable lines with cables, insulated with crosslinked polyethylene. The environment, in turn, also has an impact on the electrical cables: the values of long-term permissible load currents depend on the ambient temperature (when laying cables in the open air, in an earthen trench or in cable rooms). The impact of solar radiation on the thermal conditions of the electric cable is estimated. A comparative analysis of the complex environmental impact of electric cables with traditional insulation and insulation of crosslinked polyethylene demonstrated that unarmored cable with crosslinked polyethylene insulation at a voltage of 10 kV (regardless of the type of its shell) causes less damage to the environment than the same traditional cable throughout the considered temperature range on their surfaces.

The assessment of the suitability of cables of 6–110 kW with XLPE insulation in comparison with cables of the same voltage but possessing paper-oil insulation has been fulfilled on the basis of the method of multi-objective optimization that makes it possible to account not only the quantitative characteristics (of reduced costs), but also qualitative ones. As an indicator of the reliability of the cable line the maximum mean time to failure (the value inversely proportional to the parameter of succession of failures), which is an order more for cable lines with XLPE insulation than for cable lines with paper insulation, is adopted. A comprehensive assessment of the convenience of installation of cable lines revealed that the installation of cable with XLPE insulation features a 1.2–1.6 times easier installation as compared to three-wire (voltage 10 kW) and 1.4 times easier installation as compared to single-core oil-filled cables (voltage of 110 kW). The efficacy of the cables 6–110 kW with XLPE insulation is proved on the basis on the method of multi-objective optimization, that took into account as the costs for the construction and operation of cable lines and the reliability of its operation, ease of its installation and other quality indicators. If the goals taken into account are considered as equally important, the polyethylene-insulated cables for a voltage of 10–110 kW is more efficient as compared to three-wire (voltage 10 kW) and solid (110 kW) cables with paper insulation. Herewith, the cost of the cable with XLPE insulation may exceed the cost of cable with paper insulation up to two times. If the most important aim is to provide the minimum reduced costs for the construction and operation of the cable line, the use of cables with XLPE insulation for voltage of 10 kW is most advisable in individual cases.

The assessment of the suitability of cables of 6–110 kV with XLPE insulation in comparison with cables of the same voltage but possessing paper-oil insulation has been fulfilled on the basis of the criterion of reduced costs. Thus, the comparison was undertaken between cables of various design and material of insulation: three-core paper insulated ones vs. three-core XLPE insulated ones; three-core paper-insulated ones vs. solid wires with XLPE insulation; single-core oil-filled cables of 110 kV with paper insulation vs. solid wires of 110 kV with XLPE insulation. The increase in long-term permissible current loads for cables with XLPE insulation because of the larger permissible temperature of heating in comparison with cables with paper-oil insulation complies with as would increase in the cross-sectional area of cable cores (equal to 0.61 from the original) and therefore reduces the cost of the cable by reducing the cost of manufacture of conductors. The reduced costs of the construction and operation of cable lines with XLPE insulation (accounting the increase in the cost of a cable 1.2 and 2 times as compared with the cost of a cable with three-core insulation), despite the decline in the cost of manufacture of conductors and the reduced annual operating costs (9 % and 17 % respectively of cable lines of voltage of up to 35 kV and 110 kV), occurred to be more than the reduced costs of the construction and operation of cable lines with paper insulation. Currently the cost of one meter of cable with XLPE insulation is less than the cost of cables of AAB, CASB, AASv types of a voltage of 10 kV with aluminium cores, that ensures their undeniable efficacy.

The paper considers some informational resources of the BNTU Scientific Library.

In real-world networks, many problems imply finding the All-Pairs Shortest Paths (APSP) and their distances in a graph. Solving the large-scale APSP problem on modern multi-processor (multi-core) systems is the key for various application domains. The computational cost of solving the problem is high, therefore in many cases approximate solutions are considered as acceptable. The blocked APSP algorithms are a promising approach which can exploit many processors (cores) and their caches in parallel mode efficiently. At the same time, to our best knowledge, all blocked algorithms of the Floyd-Warshall family use blocks of equal sizes. This property limits application of the algorithms. In this paper we propose new blocked algorithms which divide the input graph into unequal subgraphs and divide the matrix of distances between pairs of vertices into blocks of unequal sizes. The algorithms describe the dense subgraphs by the adjacency matrix and describe sparse subgraphs and connections between them by the adjacency list. This approach allows the Floyd-Warshall family algorithms to be used together with Dijkstra family algorithms. It can be applied to large graphs decomposed into dense (clusters) and sparse subgraphs. A new heterogeneous algorithm can significantly reduce the computation time of blocks depending on the block type and size. The contribution of the paper is the development of a new family of blocked APSP algorithms which can handle blocks of unequal sizes, save and extend the advantages of the state-of-the-art algorithms operating on blocks of equal sizes. The proposed algorithms are implemented as single- and multiple-threaded parallel applications for multi-core systems.

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.

One of the directions of development of the electric power industry is decentralization, aimed at improving the reliability of energy supply, reducing losses during transmission of electric energy and ensuring energy independence of consumers. It is possible to simulate decentralized power systems, including distributed generation facilities, by implementation of multi-agent systems that allow solving design and control problems taking into account the needs of each participant in the process of production, transmission, distribution and consumption of electricity. The development of distributed generation using a multi-agent approach requires the creation of models for assessing the technical and economic efficiency of decisions made by each agent, both at the strategic and tactical levels. The strategic decisions of agents related to distributed generation include, among other things, the creation of power facilities and power plants based on renewable energy sources. An important factor for making such decisions is the estimation of the capacity factor. However, currently there are no models for its estimation with high reliability. The present paper proposes a new algorithm for estimating the capacity factor for the entire territory of a certain administrative unit and a model for its forecasting based on climatic and geographical parameters. The study was conducted on a data sample of 221 generation facilities (solar and wind power plants) in four oblasts (regions) of the Russian Federation. It has been determined that the capacity factor can be forecasted with a mean error within 4 % for photovoltaic power plants and 9 % for wind power plants. Therefore, it is possible to use the developed algorithm and model both in decision support systems when choosing the location of this types of power plants, and in systems that model the development of power systems using a multi-agent approach.

The paper presents an experimental study of an assembly of five stages of an electric centrifugal pump (ECP) installation, the flow part of which is modified according to the principles of biomimetics, namely using the “lotus leaf effect”. The object of the study was a 5A-35 ECP. The surfaces of the blade systems of impellers and guide devices of stages 5 A-35 were hydrophobized using the method of applying surfactant layers. The degree of impellers hydrophobicity was estimated by the wetting angle average value measured by three drops at three different points on the impeller surface. The impellers surface roughness under study was determined by the arithmetic mean profile deviation Ra and the profile height irregularities Rz. The issues related to the surfactant coating modification effect salt deposition and corrosion were studied. For this purpose, the surfaces of the original and modified impellers were subjected to intensive forced salt deposition as a result of prolonged exposure to saline solution. The conclusion about the samples corrosion resistance degree was made by changing their mass, which was due to the salt deposits formation during 15 hours of stay in solution, as well as using the drop method. Both methods have shown that the surfactant coating can serve as a salt deposition inhibitor, and the pump impeller modified by it has increased corrosion resistance. Thus, during comparative tests, a smaller mass of salt was deposited on the modified impeller sample during 15 hours of exposure in saturated saline solution than on the original sample. This indicates that the surfactant layer prevents the salt deposits fixation on the working surfaces of the pump stage. On the modified sample examined by the drop method, the indicator color changed in 20 minutes, and on the original one – in 2 minutes. Experimental studies have been carried out, during which the operation energy parameters of a five stages 5A-35 pumping package with initial and modified surfactant-coated impellers have been determined. The studies have shown a 2 % increase in efficiency in the pum-ping package of stages with modified impellers. The results of the study can be useful in the oil production, chemical industry, as well as in the housing and communal services sector.

Sources of pulsed photon radiation are widely used in science and industry. In this regard, there is a growing demand for dosimetry instruments capable of operating in these pulsed photon radiation fields. Until now there is no comprehensive methodology that describes the characteristics of reference fields of pulsed photon radiation required for calibration and verification of dosimetry equipment. The aim of this paper was to study the possibility of using a medical linear electron accelerator as a generating source of a reference pulsed photon radiation field. The paper investigates main characteristics of photon radiation field (namely, spectrum and average energy) generated by CLINAC in two modes of operation: 6 MV and 18 MV. Additionally it researches the possibility of attenuation of the CLINAC photon radiation intensity by a lead filter. The spectrum and average energy of the CLINAC photon radiation were calculated by means of Monte Carlo simulation in the Fluka program. The validation of the calculation was determined by comparing the attenuation coefficients calculated by the model with ones obtained experimentally by using real CLINACs. Experimentally, the attenuation coefficients were obtained by measuring the air kerma rate generated by the photon radiation fields of Varian VitalBeam and Varian iX CLINACs at a given point of space. Based on the simulation results, the Ḣ*(10) ambient dose equivalent ratio generated by CLINACs were calculated. It was found that the lead filter effectively attenuates the CLINAC photon radiation in terms of both air kerma rate and ambient dose equivalent rate to levels suitable for calibration of dosimetry equipment designed to measure pulsed radiation. It is shown that the lead filter significantly affects both the photon spectrum of the CLINAC and its average energy.

This article discusses the factors that affect the electrical resistance of the current spreading of the grounding device. The issue of the electrophysical parameters of the soil that affect its resistivity and the consideration of such parameters in the design of grounding devices is considered. It is shown that keeping moisture in the near-electrode space of the grounding electrode, as well as maintaining it at a certain level, facilitates improving the quality and reliability of the grounding. A relationship has been established between the ability to retain moisture and the magnitude of seasonal fluctuations in the electrical resistance of the soixl, and also the season factor, which takes into account changes under different climatic environmental conditions. The issues of application of various methods of reducing the resistivity of the soil during mounting of grounding devices are considered. One of the main ways to reduce ground resistance is the use of solutions of various mineral salts. This method is not optimal, as it accelerates the corrosion processes in the materials of the ground electrodes. Therefore, the paper also considers other ways to reduce the resistance of the ground loop; in particular, the authors propose a method for reducing the resistance of a grounding device based on the method of partial replacing the soil in the near-electrode region with a mixture with a lower resistivity capable of collecting moisture based on graphite and hydrogel. This type of mixture is environmentally friendly when used, as well as it is non-aggressive to the material of the ground loop. The principle of operation of this mixture is based on the fact that the hydrogel makes it possible to stabilize the moisture at the site of laying the circuit, while graphite increases the overall conductivity of the mixture. The paper presents the results of laboratory studies, which have been carried out in accordance with GOST 9.602–2016. For this purpose, control samples were placed in containers made of a non-conductive material (plexiglas) and dependence of resistivity on moisture, temperature, specific content of graphite and hydrogel was measured. The article presents graphs of the dependences of the mixture specific resistance on moisture, temperature, and the quantitative content of the hydrogel. From the results obtained, it can be concluded that the mixture in can be used in the energy sector to improve the reliability of electrical installations and ensure electrical safety.

The relevance of the work is justified by the need to refine the methodology for calculating cold rolling routes, associated with the expansion of factors that need to be taken into account in conducting such calculations. The aim of the work is to develop an algorithm for optimizing the routes of cold rolling of pipes using CRP and CRPR type mills, convenient for implementation in a software product. The paper analyzes the main parameters for optimizing the routes of cold rolling of pipes, factors limiting the field of optimal values of the geometric parameters of the billet‑pipe in each pass. Among the latter, the maximum possible reduction in the cross‑sectional area, the required reduction in the cross‑sectional area in the last pass, the requirement for the nature of the distribution of the reduction value in the cross‑sectional area, in the wall thickness and in the pipe diameter from pass to pass and other parameters are highlighted. The importance of minimizing the number of passes is noted. The main dependencies included in the method for calculating the deformation parameters of the cold rolling route using CRP and CRPR mills are analyzed and highlighted. An algorithm for calculating the route of cold rolling of pipes, with several iteration operations, has been developed. The proposed algorithm allows optimizing the rolling route of pipes made of any grades of steels and alloys, and allows optimizing most parameters, including those affecting the economic parameters of production. Depending on the grade of steel or alloy, some iteration operations can be excluded. The algorithm has been tested in the practice of calculating rolling routes for pipes made of carbon and stainless steels and alloys.

The paper discusses the key factors and trends in the design and production of printed circuit boards (PCB), which determine the state of the art of the automatic PCB inspection. To search for and classify defects, it is proposed to use the method of detecting defects in images based on the YOLO family of object detection models. The model was trained on a public set of images of PCB with 6 classes of defects, and the accuracy was assessed using generally accepted metrics. On the test dataset, the average accuracy according to the mAP50 metric is 0.98.

The problem of finding all shortest paths between vertices in a graph (APSP) has real-life applications in planning, communication, economics and many other areas. APSP problem can be solved using various algorithms, starting from Floyd-Warshall’s algorithm and ending with advanced, much faster blocked algorithms like Heterogeneous Blocked All-Pairs Shortest Path Algorithm designed to fully utilize underlying hardware resources and utilize inter-data relationships. In the paper, we propose a novel Blocked all-pairs Shortest Paths algorithm for Clustered Graphs (BSPCG) (in sequential and parallel forms) which utilizes the graph clustering information to significantly reduce the number of calculations by performing shortest paths search only though bridge vertices between clusters. We performed a set of comparing experiments for BSPCG and standard Blocked All-Pairs Shortest Path (BFW) algorithm on four randomly generated graphs of 4800 and 9600 vertices with different cluster configurations to determine the efficiency of calculation of paths passing through bridge vertices. All experiments were executed on a computer with two Intel Xeon E5-2620v4 processors (8 cores, 16 hardware threads and shared 20 MB L3 cache). In all the experiments the novel BSPCG algorithm outperformed the standard BFW algorithm. In single-threaded scenarios, BSPCG outperformed BFW up to 4.6 times on graphs of 4800 vertices and up to 2.7 times on graphs of 9600 vertices. In the multi-threaded scenarios, BSPCG also outperformed BFW up to times on graphs of 4800 vertices and up to 2.7 times on graphs of 9600 vertices. The proposed algorithm can be used in scenarios where clustering information stays intact or slightly modified based on the changes in graph and can be reused for future calculation of all-pairs shortest paths in the graph.

The modern development of power engineering is accompanied by a number of trends, among which one can note the decarbonization of energy production processes; an increase in the share of electricity in the balance of energy consumption due to the deep electrification of industry, transport and heat supply; decentralization of energy sources; an increase in the share of renewable energy sources, including the involvement in the turnover of secondary energy resources and energy from the disposal of organic waste; the development of practice active consumption and prosumerism. For the Republic of Belarus, in which forests are one of the main renewable natural resources and the most important national wealth that ensure the sustainable socio-economic development of the country, its economic, energy, environmental and food security, in the context of decarbonization of the power engineering sector, it is relevant to determine the importance and location of energy generating equipment using local fuels (LF), especially for heating capacities and polygeneration plants. The paper presents the results of a study conducted to evaluate the effectiveness of using mini-CHP plants on LF. The analysis of the archived data of the automated process control system of an operating mini-CHP with a heating ORC unit (Turboden 14 CHP) made it possible to evaluate its maneuverable characteristics with reference to the operating modes of the centralized heat supply system with a predominance of municipal and household heat load in it. It has been shown that the average rate of change in power is 1.5...3.0 % min; respectively, the time to reach rated power under normal conditions exceeds 40 minutes; the time to start the unit from a “cold state” varies from 20 minutes to 2 hours. Therefore the assumption has been confirmed that the studied ORC unit in particular and mini-CHP plants of a similar type as a whole cannot be considered and used as a maneuverable energy source without additional modernization. The conducted numerical study made it possible to show the opportunity of planning effective operating modes of a heating ORC unit in the configuration of the basic thermal circuit of a mini-CHP on LF with the integration of a hydrogen production module into it based on the forecast of the daily schedule of thermal energy consumption and taking into account the dynamics of changes in outdoor air temperature. Conceptual block diagrams of integrated polygeneration systems are also presented; they stand out for the use of hydrogen generation equipment from over-produced electricity during the operation of mini-CHP plants according to a thermal schedule and participation in the coverage of the electric load schedule of the Unified Energy System of Belarus. The use of thermal circuits with thermochemical hydrogen production technology and the operating mode of the ORC unit at rated power is shown to be promising for newly designed mini-CHPs on LF.

There is a large number of factors that affect the long-term permissible load currents of power cables, including environmental conditions, the method of laying, as well as the geometric, thermal and electrical characteristics of the cable structure. The catalogs of manufacturers of power cables with cross-linked polyethylene insulation do not specify the long-term permissible load currents, which would take into account the cross-sectional area of the screen, the presence of aluminum polymer tape and armor made of aluminum wires. These components can have a significant impact on the permissible load due to the currents induced in them during two-way grounding, which leads to additional heating of the cable. The purpose of this study is to analyze the influence of the above-mentioned factors on the long-term permissible load currents. The paper presents formulas for calculating the long-term permissible load current, which take into account the design features of the cables under consideration. The calculations have shown that the permissible load can decrease by 6 % with an increase in the cross-sectional area of the screen from the nominal row by one step. The introduction of an aluminum polymer tape into the cable structure changes the permissible load by no more than 2 %. The presence of armor can lead to a decrease in the permissible load by up to 18 % and its increase by up to 13 %, depending on the section of the core and screen, the method and conditions of laying. The calculation results obtained differ from the catalogdata by up to 25%. While the obtained errorsindicatetheneed to formcoefficientsfor a moreaccuratedetermination of the long-term permissible cable currents.

A separate generating complex is considered in this paper. The main feature of the complex under consideration is its functioning during the control period when the fuel resource is severely limited. The main function of the complex is the production of electrical and heat energy for the needs of the consumer. A control model for production has been developed for two scenarios, viz. of the unconditional provision of the consumer’s needs with electric energy and of the mandatory implementation of the schedule for the release of heat energy. The features of the implementation of the model for a separate thermal power plant (mini-thermal power plant) with a guaranteed supply of electric energy to the consumer are considered, cogeneration modes are substantiated in conditions of a limited fuel supply, regardless of the consumer category. An optimization option is shown when choosing an additional source of heat to meet the needs of the consumer. In the case of choosing a renewable energy source (RES), the management of the ‘cogeneration – RES’ complex according to the proposed strategy allows minimizing the required RES capacity. The basis of production management is the mathematical model of the generating complex, presented in our paper. In terms of describing the behavior of a complex physical system as a whole, an ener-gy approach (Hamilton's method) was used, which turned out to be very convenient for solving the problem, since the variational principles do not depend on the choice of a coordinate system. The description of the turbine plant as an object included in the generating complex and largely determining the relationship between fuel consumption and the amount of electrical and ther-mal energy produced is made with the unconditional fulfillment of the following requirement: fuel consumption is a function of the state of the system. The proposed cogeneration strategy in the conditions of a severe limitation of the amount of fuel does not depend on the type of fossil fuel used and is not tied to the control period calendar dates.

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.

Foundry production is a versatile industry that allows the production of products of almost any configuration and geometric dimensions. These products can be made from materials based on various metals and alloys, bimetallics, and composite materials. The obtained products can have uniform or gradient properties. However, to obtain a product with significantly different properties on the surface and in the volume from the casting, it is expedient to apply coatings with desired properties on the castings that complement the properties, allowing the improvement of coating performance. The paper focuses on the production of cast composite materials with improved surface properties. Various types of coatings based on high‑entropy alloys, cermets, polymers, carbon nanotubes, capable of enhancing the properties of cast composite materials, are considered. The classification and peculiarities of applying these coatings on the surface of composite materials are presented. The prospects of using these coatings to improve the properties of cast composite materials are shown.

This paper presents the results of a study on the effect of pressure treatment (direct hot extrusion) on the structure of graphite inclusions and the metallic matrix of high‑strength austempered ductile iron. Comparative analysis of the cooling processes of the cast high‑strength ductile iron billet without deformation and after deformation was carried out using simulation modeling methods. The results of the study on the effect of hot deformation (up to 950–970 ℃) on the fracture structure and mechanical properties of austempered high‑strength ductile iron billets are presented.

To organize reliable control over emissions from chimneys of energy facilities, automatic monitoring systems are needed. Equipment is known for monitoring emissions from small-diameter chimneys, but for large-diameter pipes (15 m or more) available in our Republic, there are no corresponding technical solutions. The paper examines the problem of automating the sampling of flue gases based on an electric drive in large-diameter chimneys. To ensure the optimal trajectory of the sampler in the chimney section, it is necessary to use an asynchronous electric motor with a frequency converter and a position sensor. A functional diagram of the control system is proposed, which contains a programmable logic controller for generating the motion mode, as well as a method for calculating parameters and expressions for generating a task signal for continuous sampling mode. Since the range of speed control increases as the diameter of the chimney increases, depending on it, scalar or vector frequency control can be applied. An expression is proposed for calculating the optimal value of the parameter N of an incremental position and speed sensor (encoder), which contributes to a reasonable choice of sensor. The results of simulation modeling are presented, confirming the effectiveness of the proposed method for calculating the parameters of the sampler drive.

Due to the development of electric transport and the growth of “green” energy, electric energy storage systems (ESS) are increasingly being used in the world. The growth of the battery market in the last decade has been 20-30%. One of the ways to increase the efficiency of an electric power storage device is its hybridization, i.e. the use of heterogeneous battery units. The paper examines the features of passive coupling of lead-acid and lithium-ion batteries in a hybrid storage device. A model is presented for calculating the electrical characteristics of these units during operation. The possibility of choosing a hybrid drive structure that provides a comparable operating voltage range of the units (operation without voltage converters) is demonstrated. The modes of operation of a hybrid energy storage system are modeled both for simple parallel connection and for switching blocks according to a threshold algorithm. It is demonstrated that in order to equalize the discharge rate of the main and additional units, it is necessary to coordinate the capacity of the ESS, the degree of hybridization, the type of load and the electrical parameters of the batteries, which is impossible without modeling the system. When the threshold switching of the blocks takes place, additional control parameters, making it possible to change the discharge rate of the additional block and increase the economic efficiency of the hybrid ESS. Estimates of the economic efficiency of hybrid ESSs have been made for different values of the threshold switching voltage of the lithium-ion unit, as well as for three characteristic loads: an electric forklift truck, a 30-apartment apartment building and a 300-apartment residential complex. The results demonstrate the features and technical and economic potential of passive hybridization, can be used for the design of hybrid ESSs for small power systems with solar and wind power plants, in the calculation and design of generator – storage – consumer systems.

The paper presents the results of a study to determine the rational structure of mini-CHP (Cogeneration Heat and Power Plant) using local fuels types (LFT) for operation as part of the United Energy System (UES) of Belarus with a surplus of electricity generating capacity and dominance of imported types of energy resources (natural gas and nuclear fuel) in the fuel balance. When optimizing the operating modes of mini-CHPs using LFT and operating in parallel with the UES, which has a significant surplus of electricity generating capacity, it is necessary to separate options for existing stations and options for newly built ones. In the first case, due to the fact that the power of the equipment is known, it is advisable to consider two extreme options, i.e., the operation of the heating unit according to an electrical or thermal load schedule. In this case, in order to maintain the daily consumption traffic it is necessary to provide for the accumulation of thermal or electrical energy, respectively. In the case of new construction, the optimized parameter is the power of the generating equipment, so it is advisable to give preference to the option with the maximum number of hours of use of the rated power. In order to increase the economic attractiveness of mini-CHP, options for developing the structure of mini-CHP using LFT with the transition to multi-generation technologies and adaptation to the existing operating conditions of the UES of Belarus have been considered. The results of an analysis of commercially available technologies for storing excess electrical energy are presented in accordance with current and projected (until 2030) cost and operational indicators. For adapting mini-CHP to operate in the UES in conditions of a surplus of electrical power capacity, an electrical energy storage system using hydrogen as an intermediate energy carrier is of greatest interest. To utilize the excess electrical energy consumption from a mini-CHP with a heating ORC unit during the daily dips, a structural diagram configuration using an alkaline electrolysis module for hydrogen production is proposed. The efficiency of energy storage and use technology is considered depending on the specific energy intensity for various electrical energy storage technologies. The use of the two most energy-intensive energy storage technologies is proposed: accumulation based on electrochemical batte-ries and the “electricity-hydrogen” type. During the study, an analysis of the functioning of the ORC-installation Turboden 14 CHP ORC-installation operating as part of a mini-CHP using LFT was carried out. It was revealed that today the installation operates in a wide range of load changes (from 17 to 87 % of the rated electrical power), while the generation of electrical energy from thermal consumption varied in the range from 0.20 to 0.026 MW/MW. Due to the fact that the ORC installation under study is a component of the energy source with a high installed peak thermal power, in the current state there is no direct correlation between the outside air temperature and the generation power of the ORC installation. This circumstance indicates the need to continue the study of heat load trends to build functional models for short- and medium-term forecasting of heat load depending on the time of day and average hourly outside air temperature, which was implemented in the second part of the work.

Steel underground gas pipelines occupy a significant share of the total length of gas distribution pipelines, and therefore their maintenance in proper condition is a constant and very urgent task. Due to its global nature, the main influencing factor affecting the technical condition of any steel underground pipelines, including gas pipelines, is corrosion, primarily soil corrosion. To protect against it on pipeline networks, along with insulating coatings, electrochemical protection (ECP) is applied, that is, following the definition of STO [Standard of Organization] 17330282.27.060.001–2008, protection of metal against corrosion in an electrolytic environment, carried out by establishing a protective potential on it or eliminating the anodic potential shift from the stationary potential. In the gas distribution industry of the country, methods and means of electrochemical protection have been applied since the beginning of gasification and the construction of the first gas pipelines. All gas supplying organizations of the State Production Association for Fuel and Gasification “Beltopgaz” (six regional and Minsk city), which operate gas distribution facilities, have specialized corrosion protection services. These services provide maintenance of available ECP equipment, conduct electrical measurements on gas pipelines and corrosion studies of soils, and have certified laboratories. This paper is devoted to the analysis of domestic experience in organizing electrochemical protection of steel underground gas distribution pipelines, searching for promising directions for its improvement and increasing efficiency through the implementation of a unified industry technical policy, automation and telemechanization of ECP equipment in the general context of digital transformation, optimization of the timing and volume of maintenance.

The work discusses a number of techniques for segmenting dermoscopic images of skin lesions to identify the areas occupied by these lesions. Segmentation is necessary as the first stage of most methods of computer diagnostics of malignancy of neoplasms. A number of techniques, such as ABCDE, use the shape of the tumor as one of the criteria for making a diagnosis; for others, such as the use of convolutional neural networks, identifying the tumor allows one to increase the accuracy of the results obtained. The work discusses three methods of segmentation: thresholding using Otsu's method to calculate the threshold value, a convolutional neural network built on the U-net architecture, and a similar convolutional neural network with an added attention mechanism. The advantages and disadvantages of each method are considered, as well as the possibility of using them together to obtain the best segmentation results.The paper considers the application of an algorithm based on a morphological projector for determining structural differences for comparing dermoscopic images. This will allow to identify changes that have occurred in skin lesions over time, for a more accurate diagnosis of their malignancy. The proposed algorithm makes it possible to detect differences in images even if there is a significant difference in the brightness and color levels of the compared images, and also ignores small insignificant details, such as noise, dermatoscope optics marks, hair, etc. A method for correcting the desynchronization of images using the structural similarity index as a similarity metric, and the sine-cosine algorithm as an optimization algorithm is proposed. The proposed algorithms were tested on dermatoscopic images and the possibility of their application was demonstrated.

The problem of calculating a quantitative quality assessment of digital images of metal object fractures recorded by a camera or a digital microscope is considered. Quality assessment is performed when the reference images are absent. The paper presents an approach based on calculation of local estimates followed by analysis of their distribution. Several variants for calculation of local estimates have been studied. Those whose distribution is unimodal were selected. It is shown that the average of local estimates is an acceptable general characteristic of image quality if they have a normal (Gaussian) distribution. In this case, the average is one of its parameters. Otherwise, the parameters of the Weibull distribution can serve as more accurate quantitative characteristics of image quality in general. The proposed approach divides more objectively the set of the analyzed images into two groups those with satisfactory or unsatisfactory quality for performing expert studies using images. Examples of the quality assessment of different object images recorded at different resolutions are presented.

The paper presents an analysis of the methodology for calculating the parameters of hot‑rolled low‑carbon steel strip on a 1600 wide strip mill. Based on the analysis, a computer program for quick calculation of rolling parameters has been developed. A solid‑state model was constructed and the rolling process was simulated in the QForm environment. A comparative analysis was carried out with the passport data of the “Danieli” unit based on the modeling results. The obtained modeling results do not exceed the maximum allowable deviations for rolling force and geometric parameters of the hot‑rolled strip.

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.