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Objective. The purpose of the study is to develop the design of a thermoelectric installation for lifting objects from shallow reservoirs using the freezing method, as well as its calculation, analysis of parameters and electrical and thermophysical characteristics. Method. The research is based on the use of methods of thermodynamic analysis, full-scale and computational modeling of cryogenic equipment in order to find optimal solutions for the reliability and service life of low-temperature installations. Result. The installation includes a waterproof probe, on the end surface of which, facing the bottom of the reservoir, thermoelectric modules are installed, heat is removed from the hot junctions of which by means of a heat removal system made in the form of an all-metal heat pipe or in the form of a thermal thermosiphon. The connection between the object lifted from the reservoir and the thermoelectric installation is carried out through a cold wall by freezing. The thermoelectric installation was calculated and its parameters were determined. Graphs were constructed and dependencies were obtained describing the main characteristics of TEMs included in the thermoelectric installation. The graphs are presented at a temperature of the hot junctions of the TEM of 300 K and the achievement of such values of the thickness of frozen water ice on the cold wall of the technical device that would allow lifting objects from a reservoir up to 4 m deep. Conclusion. The installation parameters have been determined: the number of TEMs of the DRIFT-1.2 type is 8, the operating power range of a single TEM of the DRIFT-1.2 type is from 14 to 40 W with an average temperature difference between the junctions of 45 K, the supply current is from 3.8 to 7 .6 A with power consumption from 50 to 200 W, coefficient of performance - from 0.1 to 0.45, minimum temperature of the cold wall of the TU - 248 K, a domestically produced thermal thermosyphon is used as a heat removal system from the hot junctions of the TEM.

Introduction. According to current regulations, values of required heat transfer resistance of external enclosing structures must comply with the purpose of a building, a structure itself and the number of degree days in a heating period. This technique applies to all external enclosing structures, including windows. However, windows have greatly lower heat transfer resistance than solid envelopes. Therefore, windows have a greater effect on temperature than solid envelopes at the boundary of habitable space in a room.Materials and methods. The resulting temperature at the boundary of habitable space is lowest when outdoor temperature is lowest, or when temperature is lowest for five days in a raw. It has been found out that during such periods standards of resulting temperature are not met. A regression curve, made using the least squares method, is presented; it describes the relationship between t592 and the heating season degree-day (HSDD) for nursery and junior groups of preschool institutions in 30 cities of the Russian Federation. Some points are below the trendline. It is for such cities that it is proposed to take into account not only the HSDD, but also t592 when standards are set for resistance of windows to heat transfer.Results. Resulting temperatures at the boundary of habitable space in a room are determined. They show that optimal requirements for resulting temperature are never met, while acceptable requirements are met for all values of heat transfer resistance of windows and exterior walls, even if resistance to heat transfer is normalized. As for the local asymmetry of resulting temperature, its standards are also met at all times. Values of resistance of windows to heat transfer are calculated to find those that correspond to optimal resulting temperatures at the boundary of habitable areas of rooms for nursery and junior groups at preschool institutions if basic values of resistance of exterior walls to heat transfer remain unchanged. In a large number of cases, values of resistance of windows to heat transfer greatly exceed the maximum value set by Construction Regulations 50.13330.Conclusions. If the choice of a large value of window width is only explained by aesthetic reasons, the window’s resistance to heat transfer must exceed 0.8 m2∙°С/W, despite higher costs of such windows.

The aim of this study is to determine the functional dependence for the calculation of the re-quired power of the electric motor of the traveling mechanism of the overhead traveling crane on the load capacity and span. The set aim is achieved by solving the following problems: figur-ing out how to calculate the power of the electric motor of the overhead traveling crane mecha-nism by the traditional methodology; selecting constants known from the initial data and varia-bles that require additional calculation; collecting and arranging statistical data - values of varia-bles for overhead cranes of different spans and load capacities; determining regression equa-tions based on statistical data - functions of two variables from the load capacity and span; sub-stituting the equations for the power of the overhead traveling crane mechanism from the load capacity and span. In the process of solving the set tasks, it was found that the greatest difficulty is the determination of static resistance and crane mass. Traditional calculation of these parame-ters requires the use of additional reference data and making design decisions of high responsi-bility. When searching for regression equations, the cubic model is-used, which provides high accuracy and does not overload the equation with summands. The most important result is the derivation of the final expression for determining the motor power as a function of two varia-bles - load capacity and span. The importance of the obtained results is that the proposed meth-od of calculation significantly reduces the time for the selection of the electric motor in the de-sign of a new crane, because there is no need to calculate or select additional parameters that are included in the traditional calculation. The proposed regularity is easier to integrate into comput-er-aided design systems. Since the calculation was based on statistical data of cranes manufac-tured and successfully operating, the probability of erroneous calculation is practically excluded.

The urgent task of forensic expert science is the development of methodological bases of judicial examination of construction facilities design documentation, which differ from the methodological provisions of non-judicial state (or non-state) examination of design documentation. Purpose: to undertake a comparative analysis of judicial examination of construction facilities design documentation and non-judicial examination of design documentation carried out in accordance with Article 49 of the Town Planning Code of the Russian Federation. Methods: empirical methods of comparison, description, mathematical calculations; theoretical methods of formal and dialectical logic; specific scientific methods of modeling and interpretation of legal norms. Results: the article develops and formulates the definitions of the basic concepts of judicial examination of design documentation. On the basis of comparative analysis, the authors identify some analogies and differences in the tasks and methods of research in the procedure for conducting judicial and nonjudicial examination of construction facilities design documentation. The article considers procedural features of the application of existing norms to the composition, content and presentation of design documentation as well as to the calculation substantiation of design decisions. Some problems of carrying out judicial examination of construction facilities design documentation are revealed: insufficient level of qualification of forensic experts; errors related to misunderstanding of the subject, purpose and objectives of forensic examinations. The necessity and specifics of individualization of design documentation in the course of judicial and non-judicial expert examination of construction facilities design documentation are noted. It is established that the basis for a forensic report is the assessment of the impact of non-compliance of design solutions with the normative rules on the reliability of the designed structure. Methodological recommendations are developed for assessing construction facilities design documentation.

The article tries to substantiate the extension of the list of accounting methods, which make up the method of current bookkeeping. Focus is not made on specifying content of the present and established in practice ways of accounting but on insertion in the list such elements of the method that foster realization of tasks facing the current accounting within the frames of informational support of management and outward control. At the same time these elements of the method were not taken into consideration in the regulatory framework. According to the author, extension of the list of elements of bookkeeping methods can build a frame for shaping the home regulatory framework in bookkeeping. Reorganization of Russian accounting rules (standards), which can be traced lately, demonstrates timeliness of introduction of new approaches to elaborating the system of enactments. Insertion in the list of key issues liable to regulation of matters of methodology underlines the importance of the principle of content priority over form. It can help adjust regulatory framework in accordance with procedure and technological principle. The author put forward methodology, which can be applied to any type of objective accounting.

The purpose of the article is to study the application of an institutional approach to product calculation to study the asymmetry of information on production costs at enterprises of the agro-industrial complex (AIC). This problem is formulated in the context of the categories “uncertainty, rational choice, opportunism”; sources of asymmetry for the crop industry are identified in the form of uncertainty of cost elements, irrationality of using methods of production accounting and choosing distribution bases, causes of opportunism of accounting staff. Within the framework of the study, the improvement of cost calculation is based on the application of the provisions of the theory of institutional economics, a systematic analysis of economic processes in the field of agriculture and AIC, the theory of accounting for production costs and calculation. The author has established that at different historical stages of the development of accounting, the calculation methodology was improved under the influence of the prevailing economic system, determined by the regulator and routines. Such criteria as the type of uncertainty, the nature of the impact on costs, the institutions formed, and the management of uncertainty reduction are substantiated and proposed as criteria determining the institutional approach to the study of calculation. In the course of the work, dialectical and logical general scientific methods were used — analysis, synthesis, abstraction, generalization, induction, deduction, analogy. We believe that the results of the study and the author’s recommendations will be useful to specialists of the Ministry of Finance of the Russian Federation and the Ministry of Agriculture of the Russian Federation, and will also find application in educational institutions in the training of economists for agriculture.

Goal. Calculation and experimental determination of middle speed vL of advancement of plasma leader channel of a pulse spark discharge in the long air interval of the double-electrode discharge system (DEDS) «tip-plane». Methodology. Bases of the theoretical electrical engineering and electrophysics, electrophysics bases of technique of ultra- and high-voltage and high pulse currents, bases of high-voltage pulse technique and measuring technique. Results. The close calculation and experimental method of determination of middle speed vL of advancement of plasma leader channel of an electric pulse spark discharge is offered in the long air interval of DEDS «tip-plane». This method is based on the offered calculation empiric formula for finding of the indicated speed vL and results of decoding of oscillograms of process of cut of in-use standard interconnect аperiodic pulse of over- and high-voltage of temporal shape of Tm/Тd≈200 μs/1990 μs of positive polarity at an electric hasp in indicated DEDS of long air intervals with their minimum length of lmin, numeral making 1,5 m (first case) and 3 m (second case). It is shown that middle speed vL of advancement in atmospheric air of front of plasma channel of positive leader of an electric pulse spark discharge in probed DEDS «tip-plane» for two considered applied cases at lmin=1,5 m of lmin=3 m numeral makes approximately vL≈(1±0,03)∙105 m/s. The found numeral value of this speed vL well coincides with the known experimental information for speed of advancement of vL≈105 m/s in atmospheric air of plasma channel of negative leader for a long storm spark discharge in DEDS «charged cloud-earth». It is set that for the standard interconnect аperiodic pulse of high- and ultra- voltage of temporal shape of Tm/Тd≈200 μs/1990 μs of positive polarity middle value of aggressive strength Ed of high pulse electric field in the air interval of probed DEDS «tip-plane» numeral makes minimum length of lmin=1,5 m near Ed1≈360,8 kV/m, and for his minimum length of lmin=3 m of − Ed2≈313,4 kV/m. Originality. The comfortable is developed in the use and reliable in practical realization technicians-and-engineers calculation and experimental method of research in the conditions of high-voltage electrophysics laboratory of difficult electro-discharge processes of development of leader hasp of long air intervals and determination of minimum electric durability of air insulation of electrical power engineering and electrophysics equipment on working voltage of classes of 330-1150 kV. Practical value. Application in area of industrial electrical power engineering and high-voltage pulse technique of the got numeral electrophysics results and offered calculation and experimental method of determination of middle speed vL of advancement in atmospheric air of plasma channel of leader of a long spark discharge will allow, from one side, to deepen our scientific knowledges about a long electric pulse spark discharge in an air dielectric, and, from other side, to develop high-voltage electrical power engineering and electrophysics devices with enhanceable reliability of their work both in normal operation and malfunctions.

Objective. The purpose of the work is to develop practical recommendations for the design and manufacture of a heat exchanger using heat pipes, which could find widespread use in heating, ventilation and air conditioning systems at facilities for various purposes. Method. The research is based on methods of thermodynamic analysis, full-scale and computational modeling of processes and objects of refrigeration and cryogenic technology, air conditioning and life support systems. Result. The implementation of the practical recommendations studied in the work on the use and design of heat exchangers using heat pipes in ventilation, heating and air conditioning systems will provide significant savings in energy spent on heating and/or cooling the air supplied to the room served by the HVAC system. To reduce heat loss in a building, it is rational to maintain air balance and compensate for the exhaust air with an organized influx of outside air, to heat which the heat of the removed exhaust air is utilized. Conclusion. Compared to a heat exchanger based on a glycol recuperator, a regenerator using heat pipes is less energy-intensive, requires virtually no maintenance, and is also more energy efficient due to the absence of a pumping device that requires electricity in the design. At the same time, the ability to completely separate the supply and exhaust ventilation flows of the regenerator on heat pipes is preserved, which is extremely in demand in medical institutions, due to the need to comply with strict sanitary standards.

Introduction. The relevance of the topic is due to the determination of the efficiency of the design and operation of heat exchangers as a result of the development of digital technologies in science and technology, including after scheduled and unscheduled repairs of devices. At the present time, a lot of normative, educational and methodological documentation has been developed. The problem is insufficient reliability of determination of efficiency of heat exchangers.Materials and methods. To solve the problem, an algorithm for calculating the efficiency of operation and repair of a plate heat exchanger is developed. The authors have created algorithms and a programme in Microsoft Excel for the design calculation of the heat exchanger, including thermal, design and hydraulic calculations of the heat exchanger, as well as the calculation of exergy the designed apparatus according to the heat exchanger design calculation programme. The web application ntcseis.ru based on the Ukit programming language can be used as an implementation of the calculation of the exergy efficiency of a plate heat exchanger.Results. Design calculation of a plate heat exchanger was performed using the Microsoft Excel programme, including thermal, design and hydraulic calculations of the heat exchanger. A manual calculation of the exergy of the designed apparatus was performed as a solution to an applied problem to determine the efficiency of the designed heat exchanger. The web application ntcseis.ru of calculation of exergy efficiency of a plate heat exchanger was developed.Conclusions. In the process of the work, the following tasks were set and solved: thermal, design and hydraulic parameters of the heat exchanger were calculated on the basis of the well-known classical methodology. The calculation results were used to determine the exergy losses of the designed heat exchanger using the calculated values of the average logarithmic temperatures and other parameters of the heating and heated heat carriers; exergy losses from heat exchange with the environment, from the final temperature difference of heat carriers, from hydraulic resistances in the paths of heat carriers; specific thermal exergy of heat carriers at the inlet and outlet of the heat exchanger; exergy flow at the inlet and outlet of the apparatus; exergy coefficient of the heat exchanger. A web application ntcseis.ru of calculation of the exergy efficiency of a plate heat exchanger is developed.

Goal. Development of the generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge in the homogeneous dielectric of the different aggregate state. Methodology. Basis of physical optics, theoretical electrical engineering, electrophysics bases of technique of high-voltage and large pulse currents, bases of high-voltage pulse technique and measuring technique. Results. Development of physical principle of development of plasma channel of an electric pulse spark discharge is executed in a homogeneous gas dielectric on the applied example of the use in calculations and experiments of the double-electrode discharge system (DEDS) with a long air interval, testing action of standard interconnect аperiodic pulse of high-voltage of temporal shape of Tm/Тd≈200 μs/1990 μs of positive polarity. The generalized formula is got for the calculation of total length of lc of the real way of development of an pulse spark discharge in an air dielectric, which allowed to formulate the offered physical principle in the following kind: «The plasma channel of an pulse spark discharge in a gas dielectric spreads from one of its points to other after a way length of lc, providing the least falling on it of electric voltage of Uc». It is shown that this principle in the first approaching can be applied and to the homogeneous liquid and hard dielectrics. Comparison of the developed physical principle of distribution of plasma channel of an electrical spark discharge is executed in a dielectrical environment with fundamental Fermat physical principle (a law) for distribution of light in an optically transparent environment, which specifies on mathematical likeness and closeness on destiny of these physical principles. Calculation estimations of falling of electric voltage of Uc on total length of lc of the real zigzag way of development in the air dielectric of DEDS a «edge-plane» with the least length of its discharge interval of lmin=1,5 m is presented, that a value Uc does not exceed 9 % from the experimental level of aggressive voltage of Umd≈611,6 кV in this DEDS for the аperiodic pulse of voltage of Tm/Тd≈200 μs/1990 μs. It is set that the estimated time of td advancement of leader channel of electric pulse discharge in air DEDS (lmin=1,5 m) on its real way total length of lc≈1,53 m makes td≈15,3 μs, and experimental duration of cut of Tdc of the indicated аperiodic impulse of voltage utilized in experiments, characterizing time of short circuit by the plasma channel of discharge of air interval in DEDS, appears equal Тdc≈td≈17 μs. Originality. The generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge is first developed in the homogeneous dielectric of the different aggregate state. Practical value. Application in electrical engineering practice and high-voltage pulse technique of the offered principle of distribution in the dielectrics of plasma channel of an pulse spark discharge will allow to develop both new and to perfect the existent methods of computer design of electro-discharge processes in the gas, liquid and hard insulation of different high-voltage electrical power engineering and electrophysics devices, directed on the increase of reliability of their operation.

The article presents constraining factors of the use of traditional approaches for timber skidding in the winter logging period in the North-West Federal District of the Russian Federation. Based on the study of scientific literature, the classification of cable-railways is given, methods of fastening the platform or cable car to the traction cable, the peculiarities of cable selection are considered. The modes of operation of cable-railways are described (without an engine – as a timber slide, with an engine without a trailing cable, with an engine with a trailing cable), the basic requirements for cable-railways and factors limiting the scope of application of such roads are considered. A methodology for determining the driving forces is proposed. It takes into account the weight of the car moving on the slope, the number of cars, the angle of inclination of the track section, the resistance to car movement, additional resistance to car movement when passing curves, the weight of the cable, its length, the friction of the cable on the ground, sleepers and other obstacles, which depends on the condition of the track structure, the density of sleeper laying, ballast protruding on the surface, cable lubrication and other factors. In addition to the above, power losses from the resistance of track rollers when they are enveloped by the running down branch of the cable, friction losses in the trunnions of the winch drums and friction losses from the cable enveloping the winch drums were considered. The article discusses the conditions under which it is possible to move the car down the slope, as well as prevent slipping and provide cable braking in the grooves of the drums. Limitations for the use of cable-railways, depending on the nature of the track, rolling stock, slope angle of the track, average skidding distance, are determined. A technical solution to improve the existing cable-railways using an articulated carriage that increases the operational properties of cable-railways, is proposed. The proposed design allows to reduce the wear of cables and to organize timber harvesting, including on nonstraight skidding trails with rotation angles up to 45 degrees. At the same time, the design of the articulated carriage can be effectively applied on cable-railways already in operation. For citation: Svoykin F.V., Svoykin V.F., Sokolova V.A., Voinash S.A., Ariko S.Ye. Application of Cable-Railways for Timber Skidding. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 115–125. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-115-125

The market of tractors in Russia has changed greatly in recent years. A number of new suppliers have appeared on the market, abandoned brands are replaced for Russian analogues and machines from friendly countries. It is hard to evaluate all the quantitative and qualitative diversity of tractors provided to agricultural producers through the system of machine tests, especially considering that every manufacturer has a large number of standard size ranges of power equipment. Nevertheless, the customer should have access to information about the basic consumer properties and the degree of effectiveness of a particular machine unit. The article provides a computational method for evaluating one of the most important functional indicators of tractors, namely, the level of impact of its wheels on the soil, using limited initial information: technical characteristics and operational documentation of the manufacturer. The algorithm given in the text was approved during testing real tractor samples. Insignificant differences in the assessment of the maximum pressure on the soil, obtained as a result of measurements and calculations (the difference is 1.9-3.3 %) indicate a high degree of reliability of the developed methodology, as well as the possibility of its application in engineering practice to evaluate the functional indicators of tractors, including taking into account changes in their size and mass parameters when equipped with ballast weights, agricultural machines, implements, dual tires, etc. To make calculations, it is enough to know the weight of the tractor, the weight of ballast loads (mounted implements), the size of the installed tires, their static radius and the amount of tire inflation pressure. The methodology will significantly improve the quality of the predictive assessment of the level of impact on the soil of both mass-produced and designed tractor equipment.

Shape optimization, as one of the types of structural optimization problems, is an important process in the design of shells, since it contributes to the creation of a structure with fine performance characteristics, expansion of design variations and knowledge base to obtain high-quality results. To solve the problems associated with determining the shape and creating more advanced structures, software packages include a special optimization module, which can be based on one or more mathematical methods, the purpose of which is to provide the best solution in the shortest possible time. The research is focused on the process of shape optimization in three well-known universal software packages: Ansys Mechanical, COMSOL Multiphysics and Simulia Abaqus, as well as in Rhinoceros modeling software with a special visual Grasshopper plugin. The purpose of the study is to analyze the technology of shape optimization in four software packages and to compare them with each other in terms of the problem-solving process, user interface, the fullness of libraries, accessibility for educational purposes and system requirements for a computer. The authors specify and describe the characteristic features of each software package. It was found that all the software packages under consideration are equipped with great opportunities for shape optimization of structures and have a variety of functionality for solving this type of tasks. The development of optimization technology in calculation and modeling software packages will allow obtaining the most effective solutions in the process of designing shells of complex shapes.

Today puts entrepreneurial activity in the framework of fierce competition, which becomes a determining factor in the way of pricing products of construction and manufacturing enterprises. Establishing a reasonable level of prices in the market of building materials is one of the main objective factors influencing the successful planning of the work of organizations, which includes forecasting the effectiveness of pricing policy and understanding the extent to which the planned pricing system will solve the possibility of successful development and opposition to competitive policy. The article introduces the method of creating a price policy of construction and manufacturing enterprises, the main goals and objectives are established. The need for a preliminary assessment of the demand for this group of goods to achieve the desired financial result was revealed. Within the framework of this scientific study, the project is presented to create a construction material costing, taking into account all components of the production cost. The importance of the influence of the market policy of competitors on the pricing of one's own range of goods is substantiated. Factors and pricing methods are considered. Special attention is focused on determining the final price of products.

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Objective. The present article discusses the issue of modeling the duration of the refrigeration effect on a food product using the example of raw lean meat.Method. The duration of the refrigeration effect consists of two stages: cooling and freezing. At the same time, the thermophysical characteristics of products are determined practically on a specialized experimental setup developed in the laboratory of the Department of Technological Equipment and Life Support Systems.Result. Knowing the technological regimes, it is possible to determine the time spent on cooling and freezing various food products.Conclusion. This technique can be applied in wide climatic conditions in the production of the Russian Federation on a large scale. If we increase the air speed at the surface of the product to 3 m/s, we will get a reduction in time by 502 s, provided R = 0.015 m and δ = 0.125 m. Having the initial and final conditions, you can quickly determine the duration of the refrigeration exposure, both for raw lean meat, and for any other food products, choosing the optimal one.

The mechanism for lifting the load of bridge-type cranes, as a rule, is placed on a cargo trolley moving along the crane bridge. The weight of the cargo trolley and the weight of the load create a bending moment on the bridge. The bending moment is the main force factor in the calculation of the metal structure of the crane, that is, its value largely determines the metal capacity of the crane. Therefore, minimizing the weight and size parameters of the lifting mechanism is one of the most important tasks in the design of bridge cranes. In the classical methods of calculating the mechanism for lifting the load of a bridge type crane, the elements of the mechanism are selected on the basis of their sequential calculation, taking into account the corresponding safety factors. This approach does not imply variation in the parameters of the lifting mechanism and does not allow achieving its minimum weight and size indicators. Minimizing the weight and size parameters of the lifting mechanism of a bridge-type crane can be provided by comparing various variants of its layout schemes. This can be achieved on the basis of multivariate calculation. Obviously, the multivariate calculation of the lifting mechanism of a bridge-type crane increases the amount of calculations and is very time-consuming to implement manually. This determines the relevance of developing a methodology for multivariate calculation of the mechanism for lifting the load of a bridge type crane and a computer program that implements it. The paper presents a methodology for multivariate calculation of the load lifting mechanism, which allows varying the multiplicity of the cargo polispast, the displacement step according to the classification group of the operating mode of the drum diameter selection coefficient and the minimum rope utilization coefficient, as well as the computer program that implements this methodology.

Objective. The aim of the study is to consider the methodology for calculating a thermoelectric unit as part of a thermoelectric system (TPS) intended for thermal exposure in medical practice, as well as the results of a numerical experiment carried out using it.Method. The calculation model of the thermoelectric block, which is part of the system for conducting thermal physiotherapy procedures, is described. The model is built on the basis of standard expressions for calculating the electrical and geometric parameters of thermoelectric modules (TEM) depending on the thermal and electrical parameters of thermoelement (FC) materials, heat and cooling capacity values, and characteristics of heat removal systems from FC hot junctions.Result. According to the calculation model, the thermoelectric unit was calculated, which is part of the system for conducting thermal cosmetic procedures, developed in the laboratory of semiconductor thermoelectric devices and devices of the Daghestan State Technical University on the temperature difference between the junctions for different values of the supply current, as well as the dependence of the voltage on the TEM on the magnitude of the supply current at different values of the temperature difference between the junctions, the change in temperature at the cold junction and the power of the TEM on the supply current. The graphs are calculated at a hot junction temperature of 320 K.Conclusion. As a result of calculations, it was found that the operating power range of TEMs of the TV-127-1.4-2.5 type is in the range from 8 to 17 W with an average temperature difference between the junctions of 45 K. In this case, the supply current will be 1 .5-3.5 A with a power consumption of 20 to 80 watts. The refrigerating coefficient varies from 0.1 to 0.5. In accordance with the tasks to be solved, the thermoelectric unit of the device should include four TEMs of this type.

ABSTRACT: Introduction. Mineral wool is one of the widely used materials in the construction industry. A wide range of technologies and structures with integrated mineral wool is also connected with the following: ventilated facades of buildings, facades made using FICS (facade insulation composite system) technology, insulation of roofs and attics, and much more. Methods and materials. Under different conditions, the nanostructure durability for mineral wool fibers will vary significantly. Currently, there are no scientifically based methods for assessing the durability of the nanostructure. Results. The article proposes to evaluate the nanostructure durability for the of mineral wool fibers based on the developed method of chemical destruction of building ceramics. The methods of laboratory analysis of the building ceramics material and their modernization for the nanostructure of mineral wool fibers are given. Discussion. According to the results of experimental studies, it was found that the corrosion process in the mineral wool material occurs by the mechanism of reaction of alkali metal hydroxides with silicon and aluminum oxides in the mineral wool material, removing them into solution and leading to chemical destruction of the material, which is generally similar to the studied process of destruction of the wall ceramics material. The results obtained allow us to conclude that the process of chemical destruction of mineral wool has a greater dependence on temperature and less dependence on the concentration of hydroxides than the process of destruction of brick material. Conclusions. The results of the conducted studies allow us to calculate the temperature coefficient of the destruction process rate in the Van't-Hoff formula, the coefficients in the Arrhenius equation and the value of the activation energy of the destruction process. Examples of field studies are given.

The purpose of the article is to select the cam profile (with equal design parameters) for driving the plunger of a high-pressure pump that provides the maximum speed and permissible acceleration of the pusher. A method of selecting a cam profile by analyzing combined graphs of changes in the path, speed, and acceleration of a cam pusher of various profiles using the Mathcad program is proposed. Calculations have been performed and combined graphs of changes in the path, speed, and acceleration of the cam pusher with tangential, convex, and concave profiles have been constructed. A comparative analysis of the combined graphs showed that the maximum speed of the cam pusher with a concave profile is 1,5 times greater than for cams with a tangential or convex profile. A cam with a concave profile is recommended for driving pump plungers of low-speed marine diesel engines (up to 250 min–1). To create ultra–high pressures (more than 120 MPa), the fuel supply system must be batterytype with a drive of small diameter plungers (4–6 mm) from an eccentric shaft with a special-shaped washer and electronically controlled injectors.

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Some methods for determining small angular deviations have been considered on the example of building objects. The design of an electrostatic cylindrical sensor was put forward, and the use of force action of an electric field was proposed in order to increase the sensitivity of the sensor. The main structural elements of the sensor are a plumb-line weighted at one end and a cylinder surrounding it. The conditions of equilibrium and instability of the position of the plumb arising due to positive feedback in the electric field were considered. An estimated calculation of the time of movement of the plumb until the moment of its touching the inside of the cylinder was made. The calculation result could be taken as a starting point for finding the desired angular deviation. The inaccuracy in the manufacture of the device and the random factors were noted to become influential at small deviations. The paper proposed some ways to solve these problems.

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The paper presents a comparative theoretical analysis of the movements of the curved rods of various curvature forms, which can be applied as tools for ultrasonic treatment of holes in fragile materials. It has been shown that the traditional processing of holes by an ultrasonic method is based on the use of straight rods, in which the amplitudes of displacements on the working – free end corresponds to the value of displacements at the point of its attachment to the ultrasonic oscillation concentrator. Supplementing the configuration of a straight rod with a curvilinear shape in the form of a circular arc or a spiral twisted by one turn will allow obtaining additional displacements caused by the elastic properties of a section with a curved shape. The paper considers several calculated schemes of a curvilinear rod bounded by angles j equal to p/2, p and 2p, fferent direction of the external force action. The obtained results have shown that an increase in the circular arc angle leads to a corresponding increase in the elastic displacement index of the rod free end. In this case, the total displacements of the rod free end will be made from displacements caused by vibrations of the acoustic system and the displacements of a curved thin rod from an external force. Calculations have established that the magnitude of the elastic displacements of curved rods is influenced by the shape and magnitude of the angle, the direction of the external force, the radius of curvature, the rigidity of the cross section. The considered schemes of thin rods with curvilinear sections can find practical application in ultrasonic oscillatory systems for processing small-diameter holes in fragile materials. This increases the intensity of tool oscillations and improves the process performance.

Purpose To determine the effect of biometrical parameters of the radial bone and due to edge defect formed on the radius strength properties using calculation methods. Materials and methods The study of bone strength affecting factors was conducted with the aid of experimental and calculation methods. Biometrical parameters were studied in 10 pairs of the human cadaveric radius as an intact bone initially and after the formation of rectangular or triangle-shaped edge cuts. To determine the stress-strain behaviour, mathematical calculations were performed based on the beam flexural theory for isotropic materials. Computation study were conducted using the finite element method with the NX Siemens software package. Based on assumed mathematical models, the actual areas of safe loads in the presence of cuts and values of destructive loads depending on the depth and shape of a cut taking into account the initial curvature of the bone as well as the criteria of a required residual strength in variation of influencing parameters were identified by means of calculations. Results It was established that an increase in bone curvature results in the reduction of longitudinal destructive loads and in increasing values of the normal strength. The 0.05 bone curvature combined with the 0.5 cut causes a decrease in the ultimate load by 20 times (up to 4.8 % for a rectangular cut and to 5.4 % for a triangular cut). A 0.5-deep cut in the bone which curvature is 0.05 enhances the normal stress by 6.9 times for a triangular cut and by 7.8 times for a rectangular one as compared to a bone without curvature. The critical values for the curvature and depth of the cut were established which permit to avoid additional bone reinforcement. Conclusion The strength of the radius with a maginal defect depends not only on the depth of a cut but on its location, shape and on the radius curvature.

Goal. Refinement of the methodology for the development of an effective control system for an electric drive with controlled relay-type regulators for organizing a metered feed of an electrode wire using the parameters of the arc process with the possibility of using it in design practice and practice of technological application. Methodology. The proposed method for the mathematical description (mathematical model) of the system of the developed structure electric drive - arc process with current feedback of welding with a variable structure device is based on the theory of automatic control as applied to nonlinear elements, the application of the theory of operational calculus. At the same time, a selection and description of a nonlinear node in the feedback circuit in the form of a relay element with a certain structure and subsequent linearization of this element was made. As an electric motor of the electrode wire feeder, a new development of a specialized valve electric motor is used, which is used in the system with a microprocessor controller. Results. Due to the presence of a substantially nonlinear link, the calculation of the valve electric drive system – the arc process can be found on the basis of a system of nonlinear differential equations, which is practically impossible for practical application. In this work, these complications are overcome on the basis of a rational choice of the description of the nonlinear link, its harmonic linearization and obtaining on this basis a mathematical description of the system, from which, using the methodology of operational calculus, the relations necessary for calculating the parameters of the system are determined in analytical form. Originality. The problem of calculating a rather complex problem of mathematical description of the valve electric drive system – a technological link in the form of an arc process with a substantially nonlinear link in the feedback circuit in the work is solved with the effective use of a set of methodological methods, which include as a means of representing individual links, including nonlinear links selected simplifications and solutions of the obtained differential equations using original methods of operational calculus. The proposed method (mathematical model) is tested in two directions – oscillography of a real system, as well as system simulation. Practical significance. Using the developed methods for describing the control system, it is possible to calculate its characteristics and, on their basis, select the parameters for setting the electric drive controller, which allows, without additional experimental research, to obtain the necessary character of the transfer of electrode metal, and, consequently, the quality of the result of the arc process.

Objective. The objective of the study is to develop a design model of the electronic equipment cooling system based on the combined use of high-current thermoelectric semiconductor batteries of layered design and an evaporative-condensing thermal thermosyphon, as well as to study the thermophysical processes occurring during its operation.Methods. A mathematical model of the electronic equipment cooling system based on the combined use of high-current layered thermoelectric batteries and an evaporative-condensing thermal thermosyphon is presented. The design model includes a description of heat exchange processes in a layered thermoelectric element at various supply currents, determination of the amount of heat transferred through the cross-section of the channel of a thermal thermosyphon per unit of time, and the temperature values at each channel point.Result. A 2D dynamic heat conduction problem is solved for a complex system with rectangular geometry of fragments and heat sources. The temperature distribution of a thermoelement along its longitudinal axis at different values of the supply current and the change in the heat flow along its length in a thermal evaporation-condensation thermosyphon are studied.Conclusion. The results of the research have shown the effectiveness of combined use of high-current layered thermoelectric batteries and a thermal thermosyphon in electronic equipment with dense element packaging. It is shown that to increase the efficiency of electronic equipment and reduce the heat losses that occur in the heat line when the heat-generating element of radio-electronic equipment and thermoelectric semiconductor batteries are separated by a sufficiently large distance (over 0.6 m), it is advisable to use an evaporative-condensing thermal thermosyphon as a heat line.

The article notes that the software of the complex used in the Russian troops to solve in a short time the actual problem of determining the possibility of safe passage of super heavy loads on girder road bridges has the following disadvantages: 1) it can only be used for split concrete bridges; 2) the decision to pass a large load through the bridge is made only by the value of the deflection in the center of the span, without taking into account the resulting stresses in the bridge span structure structures, and without taking into account the bearing capacity of the supports. In the article, in order to eliminate these shortcomings: 1) a strict formula is obtained for calculating the deflection in the middle of beam spans made of any structural materials from the angle of rotation of their support sections; 2) based on the use of the fundamental relationship between the relative heights of girder spans, the relative deformations of the edges of their cross sections and their relative deflections, it is proved that the maximum stresses in the edges of the cross sections of girder spans from any structural materials can be calculated by the maximum deflection value in the middle of their spans; 3) a method is established for determining the ability of beam bridge supports to ensure safe passage of a heavy vehicle by the nature of changing the rotation angles of the supporting cross sections of the span structures under the influence of the movement of the heavy vehicle layout. Taking these three results into account, when upgrading the software of the measurement system, ensures that the goal of the work is achieved.

There are too many problems from the gases which constantly fly out from the exhaust pipes of cars and lorries, especially if this process takes place in the closed apartment (garage, laboratory, class, station of diagnostic or repair for transport systems with diesel or petrol engine). Practically all gases poison air, bring essentially injury to the health of people and for the all nature. Hitherto, many scientists affirm that gases create the negative hotbed effect in the atmosphere and influence to the appearance of the ozone holes. Some important experiments and investigations at the present day didn’t make. In this article there are several technical decisions not only how to decrease the negative influence of gases but the special calculations using personal computer and statistical information to describe the process by a chart.

Management accounting depends on the problem of accounting policy development in terms of rapid adaptation to modern management concepts, which also contribute to the deepening of the theory and development of management practice and accounting. The urgency of the problem is explained by the fact that the formation of accounting policy in its current form, creates the illusion of making changes in management for business owners and managers, although it only slightly streamlines the traditional accounting system and does not provide any necessary decisions and changes. There is a substitution of concepts, and this diverts attention from the current problems of development of the management system in its broadest sense, as well as management accounting. Therefore, there is a need to form a block of accounting problems as part of the overall long-term program of management system development, in which accounting policy issues will be inextricably linked with the organization of management accounting. In this regard, the author outlines the purpose of the article in terms of studying the problematic aspects of management accounting of operating costs of the brewing industry. The article reveals the features of management accounting of operating costs of enterprises in the brewing industry. The author emphasizes the need to focus on the process of cost management, compliance with the rules of the technological process, avoiding unproductive loss of resources, reducing the level of waste, which will help ensure the objectivity of the process of financial results. The article presents the author's algorithm for assigning overhead costs to accounts 23 and 90. The author proposes to disaggregate the itemj of calculating the costs of salaries for the basic salary and additional salary, especially for PJSC «Slavutych Brewery», as the cost elements «Labor costs» at this company are 27–34 %. The author considers, it would be reasonable to detail other direct costs in the costing items to understand their share in the cost structure of operating activities.

Introduction. Cardiovascular disease occupies an important place throughout the world, which necessitates the development of more effective modern means of diagnosis and treatment. The primary diagnosis of heart disease is based on analysis and processing of an electrocardiogram (ECG). Despite the fact that there are many methods and algorithms for ECG analysis and processing, one of the urgent problems of cardiology remains to obtain the most complete information about heart electric potential, respectively, the behavior of the waves P, Q, R, S and T.Aim. Development of algorithms and software for processing and analysis of electrocardiograms (ECGs), as well as calculation of heart rate and detection of arrhythmias based on Labview.Materials and methods. The methods for removing noise using the wavelet transform method to eliminate baseline deviation ,to extract ECG signs ,to calculate heart rate and to detect arrhythmias based on Labview have been adopted as a mathematical apparatus for processing and analyzing ECGs.Results. Organizing of the ECG database, developing algorithms for converting the ECG file of the database into a useful format for Labview, processing of the ECG signal with removing noise from the original ECG signal, extracting signs for obtaining ECG diagnostic indicators, calculating heart rate and detecting arrhythmias.Conclusion. An analysis of the results demonstrates that systematic approaches to evaluating ECG signals allow to avoid one-way decisions and to integrate different methods into an integrated system of ideas of the state. The implementation of the proposed algorithms using Labview programming system ensures the removal of noise and artifacts, the extraction of the necessary ECG signs, the calculation of heart contractions and the detection of arrhythmias.

The analysis of technical condition of cast side frames of biaxial three-element bogies of freight cars in operation is carried out. A refined method of calculating the strength of the supporting structure of the side frame, new aspects of design solutions, which allowed to increase the strength of the supporting structure of the side frame in operation, is proposed.

Purpose. Implementation of calculation-experimental determination of thermal resistibility of walls of aluminum alloy panels of different thickness of fuel tank of the airplane designed in Ukraine to direct action on them of normalized components of current of artificial lightning. Methodology. Theoretical bases of thermophysics, bases of theoretical electrophysics, bases of measuring technique, electrophysics bases of technique of high-voltage and large pulsed currents. Results. The results of calculation-experimental investigations of thermal resistibility of prototypes with the necessary sheeting flat rectangular panels of fuel tank of the designed airplane are resulted measuring 550 mm ´ 800 mm and from 1.2 to 4 mm thick of aluminum alloy B95 is easily soiled to direct action on them in obedience to the operating requirements of normative documents of the USA SAE ARP 5412 and SAE ARP 5416 of A-, B- and C*- component of current of artificial lightning (1А area), and also D-, B- and C*- components of current of artificial lightning (2А area) with the normalized amplitude-temporal parameters (ATPs). It is determined that the tested panels of fuel tank of airplane in 1.2 mm, 1.5 mm and 1.8 mm thick for an area of 1А and 1.2 mm and 1.5 mm thick for an area of 2А are thermally unstable to the direct shots in them of plasma channel of a storm discharge imitated in laboratory terms with the indicated components of current of artificial lightning. It is shown that thermal resistibility to lightning of the tested panels of fuel tank of airplane is determined of ATP shortened protracted C*- components of current of artificial lightning, causing appearance in them of the rounded small holes of melting the radius of rk and depth of hk. For finding by a calculation by the sizes of rk and hk in the indicated panels of fuel tank of airplane, struck in an air atmosphere a direct blow in them the imitated storm discharge, the proper close correlations are recommended. The capacity of these calculation correlations is confirmed results executed by the powerful high-voltage generator of impulsive current of artificial lightning of type of UITOM-1 of model experiments created in Ukraine. Originality. The calculation and experimental estimations of thermal resistibility of flat duralumin panels of fuel tank of the airplane designed in Ukraine are first executed to the direct action on them for the areas of 1А and of 2А of plasma channel of the imitated storm discharge with the normalized indicated documents of ATP flows on it (to the channel) A (D)-, B- and C*- components of current of artificial lightning. Practical value. Taking into account the executed calculation-experimental investigations a practical conclusion is done that for prevention in the case of direct blow in the being in an air atmosphere airplane of plasma channel of lightning with normalized ATPs indicated components of its pulsed current of self-ignition of fuel steams in the examined duralumin tank of the designed airplane and its catastrophe the thickness of wall of an aluminum alloy B95 of this tank with the proper sheeting must make no less than 1.8 mm for the area of 2A and no less than 2 mm for the area of 1A.

The presented paper provides the alternative options for determining the condition of belt gear based on the testing and monitoring. In order to carry out experimental measurements, a newly developed device for testing, monitoring and diagnostics of belt drives was designed, as well as the possibility of determination of limit states by extreme loads. The designed measuring stand allows to determine the point of destruction of the belt for an extreme load. The main objective of the experimental measurement was to determine the slip of the wedge-shaped belt. The slip was evaluated by the coefficient of belt creeping and the specific belt slip by means of the measuring stand. The measurements on the proposed device can be made when the input speed from the electric motor and the transmitted torque of the belt gear are constant while the tensioning force of the belt drive is changing or the measurements can be made when the tensioning force and input speed of the belt drive are constant and the torsional moment changes. The monitoring of specified parameters for determining the belt gear slip is made by means of sensors located at predetermined locations from which data is processed by a PC. In the paper, the analytical calculation is processed, from which the values are compared with the values measured on the proposed device.

The need to account for cost price occupies an important place in the enterprise management system. One of the important tasks of accounting for cost price is to control the cost of production. The cost price includes the total costs necessary for the enterprise to carry out production and commercial activities related to the production and sale of products, that is, everything that the enterprise costs to produce and sell products.To determine the economic benefits of selling the company’s finished products, it is necessary to know the final cost of the proposed contract. The amount of profit directly depends on the correctness of setting the sales price of products. This article discusses the assessment of the economic effect when modeling various contract positions based on the cost price of the enterprise, which will allow you to quickly solve production issues.The source data is information stored in the SAP ERP (Enterprise Resource Planning System) system: materials, component lists, component standards, etc. The source data processing and analysis system is SAP BI (Business Intelligence). To display the final result, we use a program designed for working with Microsoft Excel spreadsheets.

The paper presents a fragment of on-going investigations directed on creation of optimal information environment that ensures an access to the R&D publications from the known scientific journals and other scientific serials which are necessary for qualitative execution of scientific and technological activities on priority areas in highway engineering. A citation analysis has been applied while using data of Journal Citation Reports for selection of world scientific publications which are necessary for execution of investigations on heat and mass transfer in road dressings. Their deformations occur under various climatic conditions due to heat and mass transfer processes, interaction of transport flows and road surface that leads to crack formation in depth and on the surface of road dressings. Structure of constructive layers especially which are created with the help of technogenic wastes (asphalt-, reinforced concrete, concrete, brick scrap and products of their recycling, various wastes of production etc.) exerts an influence on heat and mass transfer. The paper presents results of investigations on heat flows, boundary layers according to viscosity, air velocity, geometric characteristics, permeability, capillary pressures in materials. It has been shown that calculations based on principles of complex number usage have specific features in engineering practice: it is required to observe their accuracy in approaches, calculation reduction due to some accuracy degradation as a consequence of transition from complex numbers to their modules with exclusion of phase shift account and related with propagation of thermal waves. In this respect calculations of heat resistance without phase shifts are considered as rather important if they are in agreement with principles based on the fact that a complexity is characterized by thermal absorptivity of the material in a great number of calculations. The investigations have been supported by Henan Center for Outstanding Overseas Scientists, Grant Number GZS 2018006 (People’s Republic of China, Henan Province).

The paper presents a computational method with the use of gas-dynamic functions of parameters of detonation in a one-dimensional subsonic flow of ideal gas behind the shock wave propagating in chemically active air-and-fuel mixture in a uniform-cross-section duct, where the resultant of normal pressure forces acting on its side surface is equal to zero. Stabilization of the shock wave is provided by the onset of thermal crisis with the air-and-fuel mixture combustion heat supply to the gas behind the wave. In this case the value of the specific speed of the combustion products is equal to the critical one. The solution of the total-impulse equation considering the above mentioned peculiarities of the flow in a uniform-cross-section duct establishes clear correlation of the specific speed of the stabilized shock wave to the rate of rise of the temperature of the gas behind it, which gives an opportunity to determine all detonation parameters. The shock wave can be initiated by the detonation of an explosive substance and carries a huge amount of energy. It is shown that the shock wave can be obtained only if the source of small disturbances itself moves at the supersonic speed. It is shown that total pressure behind the shock wave decreases significantly and the entropy increases due to the wave losses, whereas the static pressure increases significantly. An explanation of this effect is given. A formula for calculating the rate of gas temperature rise was derived as a function of the specific speed of the shock wave, the air-and-fuel mixture heat value and the heat availability factor that designates the dissociation of the combustion products and heat loss through the duct wall under specified initial conditions. The reliability of the method of calculating detonation was experimentally substantiated. The work is currently important for the evaluation of the detonation engine efficiency.

The work is devoted to solving the axisymmetric problem of the theory of pressing porous bodies with practical application in the form of force calculation of metallurgical processes of briquetting small fractional bulk materials: powder, chip, granulated and other metalworking wastes. For such materials, the shape of the particles (structural elements) is not geometrically correct or generally definable. This was the basis for the decision to be based on the continual model of a porous body. As a result of bringing this model to a two-dimensional spatial model, a closed analytical solution was obtained by the method of jointly solving differential equilibrium equations and the Guber-Mises energy condition of plasticity. The following assumptions were adopted as working hypotheses: the radial shear stress is equal to the tangential one, the lateral pressure coefficient is equal to the relative density of the compact. Due to the fact that the problem is solved in a general form and in a general formulation, the solution itself should be considered as methodological for any axisymmetric loading scheme. The transcendental equations of the deformation compaction of a porous body are obtained both for an ideal pressing process and taking into account contact friction forces. As a result of the development of a method for solving these equations, the formulas for calculating the local characteristics of the stressed state of the pressing, as well as the integral parameters of the pressing process are derived: pressure, stress, and deformation work.

The theoretical justifying of the cost accounting for the main functional products of the state higher education institutions activities is important to development of management accounting of their activities, which is performed on a paid basis. The purpose of the article is disclosure and clarification the basics of cost calculation of the main functional products of the state higher education institutions activities. The types of calculations and the objects of calculations within the educational and scientific sphere of activity of state higher education institutions were disclosed. It was determined that the unit of calculation in the accounting practice of state higher education institutions can take the following forms: natural, enlarged, cost, conditionally-natural, operational, labor, unit of performed works and services. The basis of determining the cost of any product of activity is the method of costing – a set of ways of displaying, grouping and generalizing data on the costs of creating a product in the accounting system, which provide the determination of the actual cost of the product. The main methods of costing of the functional products of the state higher education institutions activities are calculation for each contract and calculation for each process. The calculation for each contract provides for the accounting of costs for each order, job or individual case of service provision. The calculation for each process provides the procedure by which all costs are collected for the individual structural units and processes, stages of activity of a state higher education institution. In addition, the following methods of costing were investigated: the normative method, which makes it possible to achieve greater reliability in the economic justification of the product price; direct costing, the essence of which is to accumulate the direct costs, and indirect costs are directly attributable to the cost of selling. The direct costing method is quite effective, but did not find its implementation in the management accounting of Ukrainian state higher education institutions.

The purpose of the article is to improve the grouping cost by economic elements and articles to calculate the cost of production, work and services, as well as the formation of information support for the analysis of the activity results of enterprises. The procedure for the formation of technological, production and full production cost was disclosed. It was revealed that if an enterprise produces one type of product, work or service, then all expenses incurred (basic and overhead) are essentially direct. If there are several objects of accounting, then indirect costs are subject to distribution. In order to analyze the costs incurred, they are grouped by articles. Branch guidelines contain a recommended list of expense articles, but the names and numbers of such items are not the same. In agricultural and industrial enterprises, where the vast majority of products are produced, only one article “General production costs” coincides in name. A similar situation is observed when comparing expense articles between other sectors of the economy. Thus, when planning and accounting, expenses are grouped in such a way that there is no way to compare them and conduct a detailed economic analysis. In this regard, it is advisable that the cost articles in all sectors of economic activity be the same and correspond to the established cost elements: material costs, labor costs, deductions for social events, depreciation, other operating expenses. Each article should be detailed depending on industry and other features of management. Each enterprise should set the level of detail of expenses independently, guided by its own needs, because modern information technology provides the possibility of any detail. An author's approach to grouping cost by elements was proposed, which allows to get information about the created added value for each product (including data on labor costs, deductions for social events, received incomes).

Introduction. The paper discusses the use of different methods of the hardening concrete’s temperature regime, depending on the boundary conditions specified in the design and construction of the object. Such conditions include the temperature regime of concrete holding, the turnover rate of the formwork and the construction time of the facility, as well as other factors. The aim of the research is a compilation of the various methods of investigation of the temperature regime of hardening concrete, aimed at providing the required timing of the formwork and technological equipment turnover to ensuring the consumer properties of the structures. The scientific novelty of the research lies in the updating and testing of methods for regulating the hardening concrete’s heating, ensuring the formation of the required consumer structures’ properties not previously used in transport and civil construction and based on preliminary modeling of thermal processes occurring in the hardening concrete through the calculation software. The authors on the example of several large objects’ construction consider the most common situations associated with the selection of construction technology in difficult natural conditions by taking into account the required consumer properties: concreting of large-mass structures in a limited time in the warm season and low-mass structures in winter concreting. The research is relevant in view of the large-scale construction in our country as well as of the facilities’ reconstruction.Materials and methods. The authors carried out the research with the use of modern settlementmeasuring and analytical systems taking into account the change in the thermal stress state of hardening concrete as a function of the temperature change of the concrete mix over time. The use of the modern computational and analytical complex in the physical modeling of the thermo physical processes of hardening concrete made it possible to obtain results as accurately as possible and comparable with observational data obtained during the construction process.Results. The results allowed authors to project the objects’ concreting of erected in various predetermined conditions while observing the required terms of formwork turnover and ensuring the necessary consumer properties.Discussion and conclusions. The authors propose measures, the implementation of which makes it possible to build complex construction projects in a short time in special climatic conditions. The paper is useful for engineering and technical personnel and for professionals involved in the study of thermal processes of hardening concrete.

The increase of average outdoor temperatures and their fluctuations over the past 20 years (as evidenced by the records of summer temperatures in our country) has significantly increased the need for air conditioning premises where people are present for a long time, especially when they are crowded (shops, entertainment halls, classrooms, etc.). The air conditioning process is quite energy-intensive, but the growth of well-being in many republics of the former USSR, as well as the increasing complexity of the physiological adaptation of the human body to rising outdoor temperatures make it possible (and at the same time necessary) to implement these systems on a large scale. It is important to take into account that electricity prices are currently maintained at a high level for homeowners, and in the coming years the prices will only grow. Therefore, the development of new ways of significant increase of the energy efficiency of the indoor air conditioning process is of a great interest. One of these methods is the use of laminar (or close to them) moving layers of conditioned air in a limited area of work or rest of people. Such a zone, about 1.0‒1.2 m height from a floor in each apartment is, e.g., living rooms (bedroom) in which standard temperature conditions are created by means of simple air supplying and air intake devices. In the case of sedentary work of people, the height of such a zone of conditioned air should be increased to 1.3‒1.5 m. It has already been established that the use of laminar (or close to them) air flows allows to reduce the power consumption by two or more times due to significantly reduced heat exchange with the surrounding heated surfaces. Besides, the simplicity of such systems ought to be noted. In particular, in conditions of modern systems of control and management of air conditioning, the "duties" of consumers include only the installation on the control device of the initial data relating directly to the required parameters of the microclimate. At the same time, it should be noted that there is currently no complete scientific and technical description of aerodynamic and heat exchange processes in the air conditioning zone. Even in modern conditions for countries with a sharply continental climate (Russia, Kazakhstan, etc.), the problem is the choice of the type of air conditioner for its effective use in hot periods of summer. In general, it can be noted that all the problems of energy-efficient use of air conditioners must find a comprehensive solution.

Objectives The aim of the study is to develop a model of a portable thermoelectric generator (TEG), designed to operate at low ambient temperatures, the study of thermophysical processes occurring during its operation.Method A thermal model of TEG for the conditions of the Far North was created, in which five main blocks are distinguished: a heat source (human), heat accumulators, TEG implemented by a certain number of thermoelectric batteries (TEB) connected in series, heat pipes and a radiator system for intensifying heat transfer cold junctions of thermopile elements with the environment, on the border of which there are boundary conditions of the 2nd and 3rd kind. Based on the thermal model, a mathematical model of the device has been developed, which includes solving the problems of calculating the heat conduction, melting and solidification of the working substance in a heat accumulator; an electric energy generator based on a thermoelectric converter.Result The dependency graphs are obtained, reflecting the main characteristics of the developed system, in particular, the dependence of the change in the emf on the temperature difference between the TEG junctions at various coefficients of heat exchange with the environment, efficiency TEG from thermo-emf.Conclusion As follows from the obtained data, the value of the generated emf directly related to the temperature difference between the TEG junctions, and the higher the value of the latter, the higher the emf value The direct dependence of the emf is also evident. and values of heat transfer coefficients with the environment. From the graphs presented, we can conclude that to obtain a larger value of the generated emf it is necessary to select a heat accumulator with the highest possible temperature and heat of fusion. C.p.d. generator decreases with increasing generated emf Under the conditions of a numerical experiment, the maximum value of the efficiency amounted to slightly less than 8%. It is advisable to use heat pipes as heat conduits because of the minimum heat loss along their length, and crystalline sodium sulfate, crystalline sodium carbonate, and paraffin as heat accumulators.

Objectives. The purpose of the article is to examine the design of the thermoelectric system (TPP) for the extraction of foreign objects from the human body by the method of freezing, as well as the simulation of heat transfer processes in it.Method. A design and a physical model of the system for the extraction of foreign objects from the human body are proposed, in which the source of cold is a thermoelectric module (TEM) placed on a special mechanical device made in the form of a probe, which also provides removal of heat from the hot junctions of the module. A mathematical model of thermal power plants was developed, implemented on the basis of solving the problem of ice layer growth using the method of solving the non-stationary Fourier differential equation, presented in partial derivatives by reducing it to an equation with full derivatives based on the use of an extended version of the Lame-Clapeyron substitution, and power series, which describes the temperature distribution in the frozen ice layer and satisfies the boundary conditions of the problem.Result. Data were obtained on the change in temperature of the extracted object and the thickness of the ice layer over time at various values of the cooling capacity of TEM. It is established that the duration of the formation of an ice layer between the object to be extracted and the cold surface of the TEM, which is the executive element of the system, is within narrow limits that meet medical standards, while the speed of the ice growth process depends on its thickness (increasing the cooling capacity of the TEM from 1000 to 3000 W / m2 reduces the duration of the formation of an ice layer, 2 mm thick, by almost 40 s, while the temperature of the extracted object decreases from 269 K to 252 K). It is indicated that the selection of geometric parameters of TEM and its power supply should focus on the limitations on the operation of the device, as well as medical norms and standards in order to avoid the process of frostbite of the adjacent tissues.Conclusion. A method is proposed for increasing the efficiency of the system, according to which the preliminary cooling of the TPP by an external source of cold is used, as well as the use of forced TEM operation modes.

Objectives. The aim of the study is to develop a computational model of the system of thermal stabilization of elements of electronic equipment (REA), based on the joint use of working substances with a stable melting point and the liquid method of heat sink, the study of the thermophysical processes occurring during its operation.Method. A computational model of the REA thermostabilization system based on the use of working substances with a stable melting point has been created. The model includes a description of the heat exchange processes during laminar fluid motion in a heat exchanger, determining the duration of stable operation of the REA elements, depending on the flow rate and cooling capacity of a thermoelectric battery (TEB).Result. The graphs of dependences reflecting the main characteristics of the developed system were obtained, in particular, the dependence of the change in the duration of maintaining the stable temperature of the REA element on its power, the temperature of the cold junctions of the thermopile, scattering at different maximum flow rates of the heat exchanger.Conclusions. The results of the calculations determine that the duration of complete penetration of the working substance, corresponding to the duration of stable operation of CEA elements, can be within the required limits only if certain very specific conditions are met: using a sufficient amount of the working substance in the heat stabilizing system, corresponding to the temperature and flow rate of the liquid in the heat exchanger. These parameters of the thermal stabilization system must be selected based on the amount of heat emitted per unit of time by the REA element, the duration of its operation, and the characteristics of the thermopile used to cool the fluid.

Formulas of gas dynamic calculation of detonation parameters in variable cross-section ducts are presented and a design detonation diagram is given. The diagram shows the detonation characteristics of super-compressed detonation and under-compressed detonation as the function of shock wave specific speed depending on the intensity of temperature of the ideal gas in a subsonic one-dimensional flow behind the shock wave propagating in a chemically active air-fuel mixture and on the ratio of geometrical expansion (convergence) of the duct. The propagation of a stationary shock-wave the static pressure of which in the output cross-section of the expanded duct is equal to atmospheric pressure is referred to as design detonation. This means that all the energy of the shock wave at the output of the duct can be converted into polytropic work function of gas expansion in a detonation engine. Otherwise, if the flow takes place in the mode of overexpansion due to the separation of the compressive shock wave inside the duct or in the case of insufficient expansion part of the shock wave energy will be lost. The total impulse equation for a geometrically expanding duct is solved by replacing the integral describing the thrust force with the average integral value of the curve of the static pressure acting on the side wall of the expanding duct. The frictional force is neglected due to its insignificant value. It is shown that the presence of an insufficiently compressed shock wave is not possible as the shock wave moving at the supersonic speed in the convergent duct will be decelerated to the sonic speed. To stabilize it additional heat should be supplied to transform the convergent duct behind the compressive shock wave into a semi-permanent cross-section duct wherein thermal crisis stabilizing the shock wave can be achieved. The minimum value of the detonation pipe diameter of 50 mm is substantiated. Below that value sharp reduction of combustion efficiency takes place. The results of the work can be used for the computation of detonation engine thermodynamic cycle parameters.

At present time, megacities face acute problem of construction of tunnels for laying utility networks. In such large cities as Hanoi, Ho Chi Minh, there are still no solutions to the problem of laying technical pipelines, power cables, water supply and sewage pipelines. The paper describes the method of utility tunnel designing, taking into account rock composition and restricted construction conditions for each specific area, based on the use of small tunnel-boring machine. Using this method ensures reliability and economic feasibility of the tunnel construction project.

The method of concrete crack-resistance prediction at early age is developed at capillary shrinkage with use of approaches of fracture mechanics, which is guided by the concept of accumulation of defects in structure in the form of capillaries and cracks to their critical concentration of Cc. At the same time process at two stages is considered: on the first – process of formation and growth of defects and on the second – the process, which is directly accompanying destructions (fragmentation) at critical concentration of defects. As a theoretical basis of a method physical ideas of the increment volume mechanism of hollowness of cracks in the concrete model, presented as two-level structure are accepted: a matrix of the hardened cement stone with inclusions and emptiness of various form (crack) as result of the external influences, changing the intense deformed state. The main criterion of a method – the generalized total parameter of crack-resistance calculated on the basis of model schemes of growth, association, localization of cracks system, their classification by types and relative quantity in volume at the initial concentration increasing to critical, that is caused by physical processes of capillary shrinkage is established. Being based on the considered regularities of process of concrete destruction, it is offered to divide all defects of structure, both initial, and developed as a result of power and not power influences, into 5 main types. The amount of pores and cracks of the first four types depends on concrete porosity, and type V – and on the volume content of grains of small or coarse aggregate. To each type of damages, there corresponds the stress intensity factor, extent of influence and which value on the general crack resistance of material depend on quantity of this type of pores and cracks in concrete volume. The new evidence-based algorithm of crack resistance calculation at concrete shrinkage at early age by the generalized criterion, which contains the sequence of operations of calculation as for selection of structure, taking into account the factors, influencing capillary pressure and according to characteristics of properties of concrete components, its technological parameters, and for residual resource definition of concrete on its structure and properties, and also on the samples, which are selected from structures at early age is offered.

Objectives The aim of the study is to consider the design of a device for the cautery of bleeding by the method of local freezing of the blood flow zone performed using a salt with a low cryohydrate dissolution temperature, as well as to model heat exchange processes when using this technique.MethodA design for a device for cauterising bleeding using salts having a low dissolution temperature was developed. This ensures a high cooling intensity, shortening the time of formation of a thrombus stopping the blood flow. A model of the device was constructedaccording to the principlesgoverning the solidification of a viscous liquid and heat transfer associated with the dissolution of salts in water. The model was calculated using the finite difference method. A determination of haemostasis duration wasprovided by a numerical experiment.ResultsPlots of the temperature dependence of the salt solution in water over time are obtained, reflecting the duration of the device's output to operating mode, as well as plots of duration of a 3 mm thick formation of solid phase blood against the temperature of the solution for different values of blood flow pressure in the wound area.Conclusion On the basis of the numerical experiment, it was established that ammonium nitrate can be used as a working substance (salt) in the device. When it is dissolved in water, the minimum temperature of the solution is 256 K. The selection of the salt type and its quantity should be guided by medical norms and regulations in order to avoid the process of frostbite of the tissues adjacent to the bleeding zone. It was shown that the duration of blood solidification and the formation of a thrombus of the required thickness depend significantly on the pressure of the blood flow in the wound area, which must be taken into account when designing the device.

Introduction. The paper deals with the issues related to the determination and registration of the own thermo-stressed state formed in concrete while hardening and used to provide the required consumer properties in the Crimean bridge construction. Therefore, the problem is relevant because of the deadlines for the construction of such facility in the conditions of rough terrain and dry hot climate, and also taking into account the development of the unique non-class facilities in Russia.Materials and methods. The research is carried out in real-time conditions with the usage of modern measuring systems in practice, allowing to control the process of temperature and strength of hardening concrete in time. The modern computational and analytical complex, which is repeatedly tested under real conditions and by thermophysical calculations of hardening concrete of various class objects and massiveness, is used.Results. The results of the intrinsic thermo-stressed state of hardening concrete are presented in determining the permissible temperature gradient, which make it possible to accelerate the process of erecting the object with observance of the necessary consumer properties.Discussion and conclusion. The main conclusions and suggestions are made taking into account the intrinsic thermally stressed state of the concrete when it was hardened during the construction of the Crimean bridge. The paper would be interesting and useful for engineers and technical workers engaged in real production conditions, and for specialists dealing with the issues of the thermophysical processes occurring in concrete hardening and with the problems of ensuring the high consumer concrete properties in structures.