Science & Technique最新文献

{"title":"Investigation of the Dynamics of Processing Parameters in Hard Turning Modes","authors":"A. I. Pronin, V. V. Mylnikov, D. Valko, A. S. Sevryukov","doi":"10.21122/2227-1031-2023-22-6-470-476","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-6-470-476","url":null,"abstract":"One of the types of finishing operations of machining the surface of products made of metal materials is hard turning, which is carried out at elevated turning modes. When processing steels hardened to high hardness, in processing modes with the ma-nifestation of all the features characterizing hard turning, a lot of heat is released, which turns into chips during turning, while the values of the cutting force decrease, which is associated with the softening of the active surface layers of the processed material and its subsequent plasticization, which leads to a decrease in cutting forces in the contact zone. A significant interest both from a scientific and practical point of view is the issue of changing the cutting temperature and processing parameters in hard turning modes. The paper presents experimental research results and empirical dependences of the radial component of the cutting force and temperature on cutting speed and feed per revolution, at a fixed cutting depth in the modes of hard turning of hardened steel. The research has been carried out on an experimental installation specially designed for this purpose, consisting of a lathe and a stand for recording, monitoring and analyzing dynamic processes (in the form of a signal from the cutter) during turning. A cutter with replaceable ceramic cutting plates was used as a test tool, and the material of the workpieces for the research was HVG steel, subjected to heat treatment for a hardness category of 55 HRC. Computer and mathematical processing of the results obtained using the least squares method was carried out, which allowed us to derive calculation formulas for determining the values of the studied factors. The optimal values of the factors corresponding to the minimum value of the radial component of the force and the cutting temperature are determined.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"45 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ensuring Uniform Material Removal with Magnetic Abrasive Finishing of Semiconductor Wafers by Mode Control of Machining Parameters","authors":"D. A. Stepanenko, E. S. Eromin","doi":"10.21122/2227-1031-2023-22-6-477-486","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-6-477-486","url":null,"abstract":"The paper describes a solution technique for direct and inverse problems of modeling the process of magnetic abrasive finishing (MAF) of semiconductor wafers. Solution of the direct problem enables calculation of allowance removal function for the prescribed machining parameters, and solution of the inverse problem enables determination of machining parameters required for realization of the prescribed allowance removal function.  The direct problem is solved by means  of Preston equation, which is usually used for description of material removal rate when polishing optical parts. The inverse problem is considered in a matrix formulation, and its least squares solution is determined by means of generalized inverse Moore-Penrose matrix. Based on the solution of the direct problem with constant values of kinematic and magnetic machining  parameters shows that MAF with constant values of machining parameters does not ensure uniformity of material removal.  On the basis of numerical examples it is shown that close to uniform material removal can be ensured by control of magnetic machining parameters with the law of variation determined from solution of the inverse problem. It is demonstrated that the smoothness of solution of the initial ill-conditioned inverse problem can be improved by means of Tikhonov’s regularization, which in turn technically simplifies control of machining parameters","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"118 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138988226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Algorithm for Calculating Reliability of Single Linear Section of Steel Underground Pipeline","authors":"N. Strutsky, V. Romaniuk","doi":"10.21122/2227-1031-2023-22-6-519-529","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-6-519-529","url":null,"abstract":"One of the most widespread technical systems in the world is underground steel pipeline communications (heat pipelines, main and distribution oil and gas pipelines, etc.). Accordingly, reliability assessment of such technical systems and their components is of great theoretical and practical interest. At the modern level of development, reliability calculation has become a mandatory stage in the design and diagnostics (during operation) of any technical systems in ge-neral, and in particular pipeline systems. A reliable calculation, either explicitly or implicitly,  is always based on the model of the object being calculated. It is the adequacy of the model to the real physical relations and processes inside the technical object that determines the accuracy and practical value of calculation methods. It is proposed to consider a single linear section of an underground steel pipeline as a complex technical system of unequal elements from the point of view of reliability – the main element (steel pipe) and auxiliary  protective elements combined into subsystems (blocks). The algorithm for calculating  the reliability of the object is based on the method of  block diagrams, taking into account the influence of the aftereffect  of the failure of an auxiliary element (elements) on the reliability parameters of the main element, which more adequately reflects the specific features of the design and operation of steel pipelines compared with the applied static models. The variants of structural design of a steel underground gas pipeline with a protective insulation coating and with complex corrosion protection (insulation and electrochemical protection) are considered, for which refined formulas are obtained for calculating the main reliability (failure-free) indicators.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"248 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139014634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Study of Vibrations of Agrodrone Propeller-Motor Group","authors":"Penghao Gu, V. N. Rilkov, A. A. Lobaty","doi":"10.21122/2227-1031-2023-22-6-445-449","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-6-445-449","url":null,"abstract":"The problem of experimental research of the parameters of the propeller-motor group of an unmanned aerial vehicle (agrodrone) is considered. An analysis of the work performed by agrodrones in agriculture, as well as popular serial models of agrodrones produced by well-known global companies, including in the Republic of Belarus, has been carried out. A description of the design of the experimental stand, specially designed for testing the operation of the agrodrone power plant under conditions as close as possible to the real operating conditions in which the agrodrone has to operate, is given. The main structural elements of the test bench and measuring instruments that are used to conduct experimental studies of the operation of the propeller and its electric drive are described. The results of the research are presented in the form of quantitative values of the vibration parameters of the propeller-motor group of the agrodrone at given values of the input parameters of the electric drive control system, taking into account the influence of external factors. It is shown that the values of the parameters characterizing the vibrations of the propeller-motor group of the agrodrone can be different depending on the operating modes of the engines and changes in external conditions. Based on the results obtained, it was concluded that when formulating  the mathematical formulation of the modeling problem, it is necessary to take into account the influence of random factors  on the control system of the agrodrone, including vibrations caused by the operation of the agrodrone engines.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"97 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139015161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Feasibility of Building Mini-Thermal Power Plant Using Local Fuels in the Conditions of the Republic of Belarus. Part 2. Role of Mini-Thermal Power Plant in Heat Supply Systems of Cities and Settlements in Belarus","authors":"V. A. Sednin, R. S. Ignatovich, I. L. Iokova","doi":"10.21122/2227-1031-2023-22-6-508-518","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-6-508-518","url":null,"abstract":". Within the framework of ensuring the country's energy security and pursuing a policy of decarbonization of the economy in the Republic of Belarus, it is assumed to maximize the use of its own fuel and energy resources (TER). However, the question of choosing the type of heat source in centralized heat supply  systems when using local fuels (LF) remains open.  The commissioning of the Belarusian Nuclear Power Plant and the relatively high unit cost of power generation capacities running on LF inclines the scales to use boiler houses as heat sources. Based on the world experience in the development and application of heating as the most energy-efficient solution in the field of heat supply, this problem has been studied in the conditions of Belarus. It is shown that the electric capacity of mini-thermal power plants using traditional LF connected to the unified system of the country is less than 100 MW, and the main technologies implemented at mini-thermal power plants using LF in the Republic of Belarus are traditional steam power plants with water steam as the working fluid (11 power plants) and steam power plant with organic Rankine cycle (ORC) (3 power plants). Geographically, mini- thermal power plants operating on LF are located evenly throughout the entire territory of the Republic of Belarus. The number of hours of use of the installed capacity of renewable energy sources (RES) of the Republic of Belarus has been determined. Energy sources based on organic waste and biomass (over 4,000 hours per year) and on hydro resources (about 3,500 hours per year) have a clear advantage, for which indicator of the number of hours of installed capacity use is much higher than for solar and wind power installations. In addition, biomass generating capacities have the lowest coefficient of electricity supply to the combined  energy system. Based on the analysis of modern trends in the development of energy, technical and economic “attractiveness factors” for the construction of heating systems for heat supply on LF in the conditions of Belarus have been formulated, which, in addition to traditional factors (substitution of imported fuel – natural gas and oil), include improvement of the quality and reliability of energy supply to consumers in remote locations, development of polygeneration, reduction of losses  of electric energy for its transport, participation in covering the electric load schedule of the unified power system, and also indicated the possibility of creating an energy hub on the basis of a mini-thermal power plant, structured for the integration  of energy sub-sectors, distributed generation sources and the option of generating “green” energy carriers.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"79 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139025972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the Electrical Characteristics of Pulsed Microwave Magnetron Power Supply on the Conditions for Plasma Formation in the Vacuum Chamber of Resonator-Type Plasmatron","authors":"O. Tsikhan, S. Madveika","doi":"10.21122/2227-1031-2023-22-6-487-494","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-6-487-494","url":null,"abstract":"The paper presents the research results of the influence of the electrical characteristics of a pulsed microwave magnetron power supply on the microwave discharge generation conditions, determined by the operating mode of the generating  system as a whole. Plasma was formed in a vacuumized reaction-discharge volume located inside a rectangular resonator chamber. Depending on the operating modes of the microwave magnetron power supply, studies have been conducted for three modes of microwave discharge plasma generation: pulsed mode with a duty factor S ≈ 2; pulsed mode with  a duty factor S ≈ 1.15; continuous mode. Probe measurements of the microwave power in the microwave discharge plasma volume and its local conductivity have been carried out. The paper presents  the dependence of the power of microwave energy in the central area of the reaction-discharge quartz  chamber of a microwave plasmotron on the amount of power consumed by the microwave magnetron, as well as the distribution of the electrical component of the microwave discharge plasma along the length and cross-sectional plane of the working volume. It has been established that for all studied modes of operation  of the power source, with an increase in the power consumption of the microwave generator system, an increase in the microwave power recorded in the central region of the plasma discharge is characteristic. The continuous generation mode is characterized by a decrease in the uneven distribution of electromagnetic energy along the axis of the discharge chamber.  It is shown that the transition from a pulsed to a continuous mode of microwave plasma discharge generation at the same level of power consumption by the generating system is characterized by a decrease in the value of the registered microwave power in the microwave discharge plasma volume and an increase in its local conductivity in particular areas of the reaction-discharge volume.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"90 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139025277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coolant Hydrodynamics in the PWR Reactor Core with TVS-Kvadrat of Various Designs","authors":"A. Dmitriev, A. L. Burov, T. D. Demkina, A. Dobrov, D. Doronkov, D. S. Doronkova, D. D. Kuritsin, A. Pronin, A. Ryazanov, D. Solntsev","doi":"10.21122/2227-1031-2023-22-4-326-332","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-4-326-332","url":null,"abstract":". The paper presents the results of experimental studies of the hydrodynamics of the coolant in the core of the PWR reactor with fuel assemblies “TVS-Kvadrat” of various designs. Experimental studies of hydrodynamics consisted in studying the velocity fields and the process of cross-flow of coolant between adjacent fuel assemblies “TVS-Kvadrat” of various designs in homogeneous and mixed cores on large-scale experimental models, including fragments of two adjacent fuel assemblies “TVS-Kvadrat” and a gap between them. The test models differ in the number of installed grids, this is due to the fact that in a homogeneous core the hydraulic load along the height of the fuel assemblies is identical, and in a mixed core the hydraulic load is uneven due to the different number of installed grids. The hydrodynamics of the coolant has been studied on an aerodynamic open-loop based on the theory of hydrodynamic similarity, using individually calibrated pneumometric sensors. Based on the data obtained, the fields of local axial and transverse velocities in various sections along the length of the studied section of the test models have been constructed. The fields of local dimensionless transverse and axial flow velocities in the fuel bundles and the gap between the fuel assemblies “TVS-Kvadrat” of the PWR reactor core have been studied. Peculiarities of the process of transverse flow between adjacent “TVS-Kvadrat” of a homogeneous and the mixed core of the PWR reactor have been revealed. The results of experimental studies have been transferred to the developer of “TVS-Kvadrat”, that is  JSC “Experimental Design Bureau of Mechanical Engineering named after I. I. Afrikantov”,  for further use in justifying the design and operating modes of a nuclear power plant. ","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"49 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134496491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling Processes of Emergence and Growth of Fractal Structures and Chamber Defects of Thermal Power Units. Part 2","authors":"T. V. Ryzhova, D. Bukharov, S. Arakelyan","doi":"10.21122/2227-1031-2023-22-4-333-341","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-4-333-341","url":null,"abstract":"The paper describes further development of model studies with the purpose to draw analogies of the occurrence  of possible inhomogeneities and defects of the fractal type on the surface of various objects under the action of laser radiation for different conditions and schemes of a laser simulation experiment in comparison with real processes in the chambers of thermal machines due to the contacts of the working substances with their surface. The subject of this consideration is related to the fact that in laser schemes one can relatively easily and in a controlled manner to study their topology in various modifications (in the range of 0D–3D structures formed on surfaces of various geometric shapes of the fractal type). This provides great opportunities for studying various frequently occurring undesirable random defects and inhomogeneities of  complex configuration with the development of unexpected processes in the dynamic modes of operation of various types of power units in their actual operation. This is determined by geometric analysis within the framework of the correspondding non-linear models with different  non-linear fractal images. In this aspect, we have used two models to consider the development of emerging fractal fractured structures: first, diffusion propagation/growth of cracks of different geometry with a set of local segments and fragments in different directions; secondly, with diffusely limited aggregation of their distribution (Diffusion-Limited Aggregation – DLA) using the formalism of cellular automata in percolation approximation for different algorithms for the formation of fractal structures. We present only the final results of calculations without details of their procedure, which is sufficient for a visual and qualitative determination of the process of growth of fracturing and defects. In this case, the final goal of consideration is to study the emergence of possible and controllable local areas / collectors, starting from surface structures, and their association with real objects on the surface of chambers with a working substance in power systems. The possible practical significance of such modeling and analysis is discussed to forecast their working conditions.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"2010 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114866577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors for the Development of Corporate Management in China","authors":"S. Solodovnikov, Yu. Meleshko, Jing Xu","doi":"10.21122/2227-1031-2023-22-4-342-354","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-4-342-354","url":null,"abstract":"Рurpose of the work is to develop the theory of corporate management of Chinese transnational corporations (TNC) by identifying and substantive characteristics of the factors influencing these relations. The methodological main of research are systemic and comparative analysis, the method of conceptualization of scientific ideas, the method of qualitative and quantitative assessment, the subjective approach. The following are identified as the main factors determining the directions, tools and forms of development of corporate management in China: strengthening economic interdependence within macroregions, including through transnational corporations, with the growth of economic and geopolitical confrontation between macro-regions; high rates of economic growth of the country, requiring the expansion of transnational forms of doing business in order to stimulate exports and provide access to the necessary import resources; expansion of the private sector while maintaining state control over assets in key industries and the development of the national stock market; the ongoing credit and financial policy of the state, which provides Chinese TNCs with privileged access to financial resources; reconfiguration of the global technological space in favor of China, which contributes to the development of Chinese TNCs in the ICT (information and communication technologies) sector and the improvement of corporate management on a new technological basis; the leading role of the Communist Party in the political life of the country, which allows Chinese TNCs to use political capital to increase competitiveness; national cultural and worldview features that contribute to the formation of a specific culture of corporate management (guangxi), characterized by a high level of social capital and a focus primarily on collective interests. The novelty of the results obtained lies in the disclosure of a variety of factors and the mechanism of their influence on the corporate management of Chinese TNCs, a high degree of interdependence of internal and external factors, as well as in the study of economic, political and cultural factors not in isolation, but in the unity of their influence on the object of study, which allows significantly improve the quality of economic analysis of the development of corporate management in China.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131647190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of the Influence of the Composition of Hydrophobic Preventive “Protect-01” on the Physical and Mechanical Properties of Asphalt Concrete Pavement Materials","authors":"Магистр В . В . Петрусевич, V. V. Petrusevich","doi":"10.21122/2227-1031-2023-22-4-294-300","DOIUrl":"https://doi.org/10.21122/2227-1031-2023-22-4-294-300","url":null,"abstract":"During operation, the asphalt concrete pavement is subjected to various destructive influences associated with external natural, climatic and operational factors, which can cause its premature failure. Over the past 10 years, there has been a significant increase in the fleet of vehicles in the Republic of Belarus, and, consequently, the intensity of traffic on the roads with a proportional increase in wear and destruction of their coatings. This situation is exacerbated by extended turnaround times for a number of transport facilities. The need to protect asphalt concrete pavements from the effects of external aggressive environments determines the search for new technological solutions in the creation of necessary materials, the range of which is quite wide. Existing protective compositions differ both in purpose and in the content of components. Modern research in the field of protective treatments for asphalt concrete pavements of highways, as well as technological processes used in road organizations, can effectively extend their service life. At the same time, the current research work, proven technological processes, as well as the well-known works of scientists in this field offer an insufficient number of sound technical and design solutions that allow for direct preventive protection of pavements and use for this purpose available, including secondary, materials. For more effective protection of pavements from the complex effects of water and traffic loads in the autumn-winter and spring-winter period, it is necessary to develop and implement alternative technologies, one of which is the treatment of road surfaces with the Protect-01 hydrophobic prophylactic composition. The paper presents the results of studies of the effect of treatment with the Protect-01 hydrophobic preventive composition on water saturation (decrease by 30–40 %,) frost resistance (increase by 10–12 %) and residual porosity (decrease by 12–25 %) of cores from asphalt concrete mixtures, as well as its optimal formulations.","PeriodicalId":297325,"journal":{"name":"Science & Technique","volume":"8 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130145316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}