The PURPOSE of the study is development of mathematical models to study the mechanisms for improving a reliable fuel supply of remote settlements with biomass from energy plantations. METHODS. Monte Carlo method is used to solve the set tasks. The methods of mathematical statistics are used to prepare the initial data. RESULTS AND CONCLUSIONS. Mathematical models have been developed to analyze the reliability of remote settlement fuel supply with biomass from energy plantations taking into account the influence of random factors in production, consumption and carryover fuel resources. A numerical method is presented for the formation of a random value of fuel resources of long-term regulation. It is shown that it develops a Markov sequence. We have estimated the number of iterations after which the process definitely becomes a stationary one. Experimental calculations have shown that 6000 iterations are required for the process to become stationary and ergodic. This means that after this number of iteration the properties of the random process of carryover fuel resources and other characteristics of the model of fuel supply reliability analysis can be estimated by averaging of the indicators produced by iterations.

PURPOSE. This article discusses the possibility of increasing the efficiency of the heat balance diagram of the thermal power plant through the installation of steam compression heat pumps and absorption heat pumps. The project under consideration involves the installation of ten steam compression heat pumps or two absorption heat pumps in the operation cycle of a thermal power plant to increase its energy efficiency. The CHP heat balance diagram as well as the water and steam flow rate in the various elements of the heat balance diagram are calculated. The material and energy balance is drawn up. The section of heat efficiency indices calculation deals with the determination of power generating unit efficiency and natural fuel consumption. The second part of the work is devoted to the determination of the necessary number of installations of steam compression or absorption type heat pumps. The index of thermal efficiency of the CHP power generating unit with steam compression heat pumps and with absorption heat pumps is determined as well. METHODS. The heat balance diagram of a thermal power plant with the turbine K-325-23.5 has been calculated on the basis of methodical instructions. RESULTS AND THEIR DISCUSSION. The paper presents the calculations of the CHP heat balance diagram with and without the application of heat pumps (absorption and steam compression). The conducted comparative analysis allows to find out that the use of steam compression heat pump in the CHP technological cycle can increase the installed capacity of the power plant from 269.74 to 271.34 MW, and its absolute efficiency by 0.7 %. The use of the absorption heat pump in the CHP technological cycle allows to increase the power plant capacity from 269.75 to 365.61 MW, and its absolute efficiency by 2.6%. CONCLUSIONS. When calculating the heat balance diagram of a thermal power plant with the turbine K-325-23.5 the highest energy efficiency of the CHP heat balance diagram is achieved when two absorption heat pumps with steam heating are installed on the steam turbine condenser.

PURPOSE. This work presents the analysis of the regulatory and legal support of the problem of reactive power compensation and economic incentives for the correction of the reactive power factor in Russia, as well as the analysis of researches in the field of control of reactive power flows in power supply systems. METHODS. The analytical expertise of reactive power compensation methods is carried out. The procedure of obtaining an assessment of the problem of reactive power flow automated control is based on the expert opinion with a view to the subsequent decision-making. RESULTS. The need for the automation control of reactive power flows by using the monitoring properties of the automated control and accounting system of electrical energy is substantiated. CONCLUSIONS. Improvement of the quality of reactive power mode control requires a transition to active-adaptive control systems. A highly adaptive solution with the necessary operating characteristics and high economic efficiency is the use of STATCOM tools to control reactive power compensation on the 10 kV side together with the load-sensing transformer control at the power center, which will allow to automate the control of reactive power flows in the company's power supply systems.

PURPOSE. This work studies the possibility of repairing a standby electric generating unit used to start diesel engines in field conditions in the absence of spare parts and qualified specialists. METHODS. To start diesel generators of power stations 5И57A a standby electric generating unit is used. It includes molecular energy storages (MES). One of the faults of this unit is magneto failure. An experiment was carried out to eliminate this fault in the shortest possible time and replace the magneto with electronic ignition. RESULTS AND THEIR DISCUSSION. The advantage of modernization is that repair could be done quickly enough by not highly qualified personnel. The drawback is that the engine operating in this mode loses its power. But taking into account restored working capacity, the charging time of molecular storages due to the loss of power can be neglected. CONCLUSIONS. The most acceptable solution for the repair of the standby electric generating unit ignition system in field conditions in the absence of spare parts and repair specialists has been found. Replacement of magneto with emergency ignition ensures the operation of this device and allows to start diesel engines in emergency situations.

The Eastern regions of Russia have a significant potential for the development of power-generating coal production. High provision with coal reserves allows to treat coal as a long term and reliable fuel for power plants. The PURPOSE of the paper is to evaluate the reserves and resources of coal applicable for use in the power sector. MATERIAL AND METHODS. The set task is solved on the basis of the official statistical data and calculation results of the authors. The study uses the system analysis methods. The calculations are carried out on the economic and mathematical models constructed by the authors. RESULTS. The paper estimates coal reserves in the Eastern regions of Russia applicable for use at existing and new power plants. The coal deposits promising for the construction of power plants in the subjects of the federation and considered in the projects and program documents are described. Coal deposits promising for the construction of power plants but not included in strategic development plans are also described. The coal reserves in these deposits and potential volumes of coal production are assessed. The main qualitative characteristics of the coals in the deposits under investigation are indicated including heat value, content of ash, sulphur and moisture. A brief characteristic of mining-geological and hydrological conditions for deposit development is given. Coals of the Eastern regions are shown to contain valuable accompanying elements. Favorable and limiting factors for the development of the presented coal deposits are evaluated. CONCLUSION. In the long run coal will remain one of the main energy carriers in the energy balance of the Eastern regions. Creation of industrial clusters on the basis of coal deposits seems highly promising in terms of economy and ecology.

The article presents the study results of welded joints from the aluminum alloy of Al-Fe-Si system. The purpose of welding is to obtain aircraft parts. The challenge of joining light-weight skin-type parts consists in frequent defects such as flatness deviations and joint surface geometry changes caused by spot resistance welding. As the adjustment of welding mode and conditions has not yielded favorable results a decision was made to study the influence of previous operations of the technological process. The PURPOSE of this work is to study the influence of the types of primary machining of aluminum alloy sheet parts on the quality of welded joints obtained by spot resistance welding. METHODS. The influence of the blank production method and sample sheet rolling direction at nesting on the quality of welded joints has been determined experimentally. RESULTS AND THEIR DISCUSSION. The best results after welding have been obtained on the parts made by chemical dimensional etching. After resistance welding of such samples with the thinning windows of 0.9 mm and 1.1 mm regardless of the sheet nesting direction the defects were not found. After resistance welding on parts with the thinning windows of 0.68 - 0.75 mm, 0.88-0.96 performed by the mechanical processing method regardless of the sheet nesting direction the defects in the form of bucklings were identified. The parts with the increased thickness of 1.15 mm do not feature any surface deviations from flatness after welding. CONCLUSIONS. It has been determined that the appearance of geometry integrity defects after spot resistance welding on samples does not depend on the direction of sheet nesting but depends on the type of machining and the thickness of thinning windows. The residual deformation after machining can be reduced by decreasing the depth of thinning, i.e. increasing the part thickness in the thinning windows to the maximum allowable value of 1.15 mm. This eliminates the possibility of defects after welding in the form of surface crowns.

The article deals with the development of the calculation model of the infinite radial bearing lubricated by low-melting coating with simultaneous consideration of lubricant viscosity dependence on pressure and temperature. The estimation is given to the influence of the parameter K caused by the melt of a low-melting metallic coating of the bearing bush surface, the parameter caused by the lubricant viscosity dependence on pressure, and the parameter caused by the lubricant viscosity dependence on temperature on the main performance characteristics of a radial slide bearing. The PURPOSE of the article is formation of the specified calculated models of infinite radial bearings operating in the mode of hydrodynamic lubrication when there is a lubricant and a melt of a low-melting coating of the bearing bush under simultaneous consideration of lubricant dependence on pressure and temperature for the application in engineering practice. MATERIALS AND METHODS. The article proposes new mathematical models describing the motion of incompressible lubricant in the approximation for the “fine coat”, a continuity equation and expressions of energy dissipation rate for the determination of the profile of the low-melting coating melted surface of the bearing bush taking into account the influence of a number of additional factors. The performed comparison of available and newly received results confirms the approximation of the new model to the real practice. RESEARCH RESULTS. New multiple parameter expressions have been developed for the main performance characteristics of the considered friction couple that take into account the dependence of lubricant viscosity on pressure and temperature in the presence of the lubricating material and the melt of a low-melting coating of the bearing bush. An assessment is given to the influence of the parameters taking into account a range of variable factors caused by the melt of the surface of a bearing bush low-melting coating. DISCUSSION AND CONCLUSION. The present work summarizes the influence of the multiparameter variable factors. The latter significantly complicates the task but makes its solution universal and demanded in modern friction elements. The results of the numerical analysis of the obtained theoretical researches show that the sliding supports operating on the melt of the low-melting coating have an anomalously low friction coefficient (dependence of the friction coefficient on the parameter caused by the melt is close to the linear one). The received results can be used in mechanical engineering, aircraft industry, instrument-making industry and other industries where lubricant supply is associated with difficulties.

The PURPOSE of the article is to consider the possibility to improve technological resources and efficiency of vibration treatment of parts in machine-building industries by creating the working elements of machine-tools for finishing-grinding and strengthening treatment of parts, which ensure the movement of the machined parts with a large amplitude; to demonstrate the efficiency of the machine-tools with the working elements in the form of helical rotors for finishing-grinding and strengthening treatment of parts and their technological capabilities as well as to develop a methodology for calculating the machine tools drive based on helical rotors. METHODS. The analytical study aimed at creating a technique for calculating the machine-tool drive for finishing-grinding and strengthening treatment based on helical rotors is performed using the methods of theoretical mechanics, geometry and mathematical analysis. The experimental study is carried out in order to prove the efficiency of finishing-grinding and strengthening treatment in helical rotors. RESULTS AND THEIR DISCUSSION. We have created the working elements of machine tools that provide the machined part weight movement with the large motion amplitude as well as extend technological capabilities of the machining process by increasing the range of weight, size and configuration of the machined parts. The technology and the set of equipment allowing to carry out the fluctuations of the loading weight (machined parts and working media particles) with the amplitude from 10 to 1000 mm and higher have been proposed. CONCLUSIONS. A typical diagram of the machine-tool for finishing-grinding and strengthening treatment of parts in machine-building production is proposed as well as the technique for calculating the drive of machine-tools with the working elements in the form of helical rotors. A classification of helical rotors has been created on the basis of a general principle that allows to predict the development of helical rotors of new designs.

The PURPOSE of the study is to analyze the welding of high-strength rail steels for continuous welded rail in terms of structure formation in the welded rail joint performed in Russia and abroad. METHODS. Various technologies of rail welding are compared and analyzed. The structural factor in the welded rail joint is analyzed on the basis of metallographic studies. RESULTS AND THEIR DISCUSSION. Consideration is given to the main research directions and the results obtained by different authors in the field of rail welding. Analysis is given to the requirements for the continuous rail track in the field of welding for various technological methods (aluminothermic welding, flash butt resistance welding, gas pressure welding, friction welding, manual arc welding). The works are analyzed taking into account the received structures in the welding joint and the zone of thermal influence for the main methods of rail welding including aluminothermic, gas pressure, resistance flash welding, linear friction method, electric arc, and electroslag methods. The macrostructures and hardness of the welded rail joint are compared for the welding methods under investigation. In addition, the rail welding technologies introduced on the Russian and foreign railroads are analyzed. CONCLUSIONS. It is shown that in terms of the structural factor, low values of impact resilience and crack resistance at negative temperatures, high level of defect formation in the rail joint, the aluminothermic welding of rails can not be recommended for the construction and reconstruction of high-speed continuous welded railroads. This method does not provide high quality of the rail joint and reduces traffic safety. Other methods of rail welding provide high quality of the rail joint and are more promising according to the physical and mechanical properties in the welded joint. However, it is required to conduct additional studies of the processes of structure formation in the welded joint and the zone of thermal influence under conditions of negative temperatures and high specific loads on the rail joint.

This research deals with the development of scientific and technological fundamentals of plasma-chemical production of zirconium carbide. The PURPOSE of the paper is development of scientific and technological foundations for the production of nanocrystalline zirconium carbide using the results of theoretical and experimental studies of plasma-chemical processes of carbide formation. METHODS. The study uses mathematical modeling of the process with the const method. RESULTS. A continuous technological process of zirconium carbide production in a plasma-chemical reactor has been developed. A prediction is made on the possibility to use zirconium carbide in functional protective coatings.

Intensification of aluminum production by the electrolysis of cryolite-alumina melts requires constant updating and high quality of applied raw materials. For the first time in the world practice environmentally friendly oil pitch obtained by liquid-phase catalytic oxidative cracking has been used in non-ferrous metallurgy. As compared with the traditional use of coal-tar pitch its advantage is complete absence of the source of carcinogens 3,4 Benz[a]pyrene in this binder. A modified heavy pyrolysis tar with the increased coke number of up to 25 units has been also used as a binder for the anode mass. The PURPOSE of this study is development of new carbon compositions based on oil pitch containing minimum of carcinogenic substances as compared with the traditional use of coal-tar pitch in aluminum production by the electrolysis of cryolite-alumina melts. METHODS. For the first time ever the article presents the results of studying petroleum tar obtained by the catalytic liquid phase oxidative cracking. The results of the chromato-mass-spectrometry of the samples of the produced tar did not show the presence of benzo[a]pyrene in tar composition. RESULTS. The paper provides the results of testing environmentally friendly petroleum tar obtained by the catalytic liquid-phase oxidative cracking technology and modified heavy pyrolysis tar with the possibility of their practical use for modern resource-saving technology in non-ferrous metallurgy in the production of dry anode mass. CONCLUSIONS. Conducted studies show high ecological and economic efficiency of using petroleum tar and modified heavy pyrolysis tar as binding components when producing dry anode mass to obtain primary aluminum in reduction cells with Soderberg anode.

PURPOSE. The relevance of the presented studies is determined by the importance of modeling of poorly formalized subject domains, the knowledge of which is heterogeneous and has both quantitative and qualitative nature. With the advent of constraint programming technology the conditions for unifying the joint processing of heterogeneous constraints of the subject domain have emerged. However, today qualitative dependencies are not processed effectively enough. The article is devoted to the development of methods for economical representation of non-numerical constraints, as well as effective methods for their satisfaction. The research is aimed at acceleration of the combinatorial search procedures when solving constraint satisfaction problems in poorly formalized subject domains. METHODS. The methods proposed in the article develop the constraint satisfaction theory in the part of representing and improving the efficiency of joint processing of quantitative and qualitative relationships of a poorly formalized subject domain. Presentation and processing of non-numerical (qualitative) constraints of the subject domain is proposed to perform with the use of specialized matrix-like structures ( C- and D- systems). The reasoning on these structures should be implemented in the form of constraint satisfaction procedures. RESULTS AND THEIR DISCUSSION. Two theorems on the properties of matrix-like structures and their corollaries are formulated. Together with the proposed reduction rules they can successfully propagate non-numerical constraints: identify the subspaces of legal and illegal assignments in the search space by checking only a part of the values from the variable domain. Based on the corollaries of the theorems mentioned above, the modifications are developed to the known methods of constraint propagation, which provide node and arc consistency for the case of non-numerical constraints. Unlike most analogs these modifications allow the CSP to be effectively reduced, even if it was not originally represented by a set of unary and binary constraints only. CONCLUSIONS. The paper offers a complex approach to the representation and processing of qualitative dependencies in poorly formalized subject domains, which allows to provide an acceptable computational speed in the study of subject domains with complicated multiple relationships.

The PURPOSE of this work is to identify and study the features of the computer-aided design system (CAD) arising in the design of a complex and having a significant influence on the design process and its results. METHODS. The complex as the most composite type of a product and the object of design is studied on the principles of system and block-oriented approaches using the method of structural analysis. The main parts of the complex and its connections, as well as CAD features and requirements are identified using the method of analysis and subsequent synthesis. RESULTS AND THEIR DISCUSSION. Having studied the structure of the complex the requirements and features of its CAD were defined. The complex is considered as a set of structurally, functionally and operationally finished products, and their components, which are also complex products with their individual characteristics, internal structure and connections. It is shown that the creation of the complex is a complex technical and organizational task. The design of the complex is performed by separate teams differing in the level of education, design experience, technical and organizational support of the works. The big actual duration of works on complex design is substantiated. The analysis is performed and the requirements for the CAD system of the complex have been developed including: the need for information support during the entire design process; the need to ensure the compatibility of the working subsystems at the hardware and software levels; the possibility to apply various design methods, etc. The features of the CAD of the complex are formulated. It is shown that the design process is a complex logical task. The different complexity of works at the initial and subsequent design stages is justified. The latter leads to the different influence of CAD at these stages. Accordingly, the requirements for the professional qualities of designers and for the organization of the design process change. There is often inconformity with the hardware and software equipment of designers and the tasks of a new product development, which also contributes to the design of the complex in an inhomogeneous environment. CONCLUSIONS. The conducted researches allow to identify the main features of the CAD of a complex on the basis of which to improve the quality and efficiency of complex design. Therefore, the search and identification of such features is of great importance. The results of this work can be used in the development of a specific method of designing the complex.

The PURPOSE of the paper is creation of an algorithm for calculating an integrated efficiency index of university academic staff and researcher publication activity. METHODS. The rating of academic staff and researchers is necessary for maintaining the appropriate university status. Its obligatory condition is research work, particularly publication activity which includes publication of articles and monographs in the journals with a high impact factor as well as registration of a patent and acquisition of a copyright certificate. The article lists all basic indices of publication activity including the total number of articles and references, Hirsch index, impact-factor, etc., which are taken from the scientific electronic library (elibrary), data bases Scopus and Web of Science. It is proposed to improve the rating system of academic staff and researcher publication activity efficiency by developing an algorithm to calculate an integrated index which is based on elibrary indices with addition of some criteria - number of monographs, intellectual deliverables, Scopus and Web of science criteria. The aspects are divided into groups for convenient calculation of the integrated index: number of publications, number of citations, Hirsch index, intellectual deliverables. CONCLUSIONS. The main advantages of the developed algorithm for the calculation of the integrated efficiency index of university academic staff and researcher publication activity are described. The article stresses its efficiency and reasonability for the comparative analysis of publication activity of individual employees as well as departments and university as a whole. It is proposed to use the created algorithm as a basis for the development of a program to calculate the rating of university academic staff and researchers according to their publication activity.

The PURPOSE of the paper is to assess the influence of magnetic storms on road traffic safety in the conditions of the North. METHODS. The Statistica 10 program is used to process information by road accident record cards and journals of magnetic storm observations. RESULTS AND THEIR DISCUSSION. Magnetic storms affect the road safety. The conducted correlation and regression analysis has shown a high correlation between the road accidents and magnetic storms. The correlation coefficient is 0.8. CONCLUSIONS. Magnetoactive days feature sharp deterioration in human health that results in the increased number of road accidents. The announcement of meteorological conditions (the latter have been thoroughly studied being a single risk factor of road accidents) should include mentioning of magnetic storms as affecting road safety. The factor of magnetic storms must be taken into account when developing measures to improve traffic safety alongside with other factor affecting the level of road safety.

PURPOSE. The article describes the basic requirements for the transportation of schoolchildren by motor transport and the experience of schoolchildren transportation in Russia and abroad. It deals with the issue of schoolchildren transportation after classes, as well as organization of special transportation of groups of students in case of excursions, entertainment, sport and other cultural events. METHODS. The study is based on the questionnaire survey of potential users of transport services. RESULTS. The paper discusses the problems of increasing the volume of transportation, describes the conditions under which the cost and, accordingly, the tariff are reduced. The study results in obtaining the value of the tariff for the transportation of one student. Conducted survey allows to determine the feasibility of opening a commercial route to deliver students to school. CONCLUSIONS. Organization of regular school transportation is a convenient way of delivering students, especially primary school pupils to school and back. In most cases, educational institutions can not afford to have their own rolling stock. Therefore, students have to reach school on their own - on foot or by public transport. It is not always safe, especially for younger students. Sometimes parents deliver their children by car, which also brings some inconvenience. Therefore, the opening of a commercial route of regular transportation of students to school and back can be useful.

PURPOSE AND METHODS. The main purpose of the work is to create a methodology for determining the kinematic parameters of body flow which allow to use the stationary approaches for the calculation of aerodynamic characteristics of attached and detached body flow using ANSYS and parameters when it is necessary to use non-stationary approaches only. RESULTS. The paper presents a technique for choosing the required value of the aerodynamic coefficient for detached flow with a periodic character of flow parameter variation based on the theory of random processes. Methodological provisions are demonstrated by some research results of aerodynamic characteristics of wings (flat square in the planform with a thin profile and rectangular in the planform with the profile NACA 23012). Consideration is given to the features of the flow around the objects under investigation at different angles of attack relating to the main flow. Modeling reliability is estimated in comparison with experimental data. Based on the analysis of physical flow patterns of bodies and calculation results of their aerodynamic characteristics an algorithm (methodology) for determining the ranges of kinematic parameters of flow around has been developed for the solution of problems in stationary and nonstationary formulations. CONCLUSIONS. The presented results allow to evaluate the application capabilities of ANSYS when solving aerodynamic problems taking into account the flow separation and the selection of the flow model (stationary or non-stationary) as well as to carry out sufficiently reliable aerodynamic calculations of wings and other bodies considering flow separation.

PURPOSE. The problem of increasing the railroads capacity reserves and their efficient use is still relevant. As in many aspects the reserves are almost depleted it is especially important to use technical and technological approaches providing the greatest multiplicative effect in the rolling stock productivity increase for solving the set task. In this sense, the most preferable way is the intensive development with the implementation and active use of the innovation rolling stock in freight trains. It allows to raise performance indicators within the existing limitations of the railway infrastructure. RESULTS. The article has considered the innovation car influence on the enlarged indicators of high-performance use of the freight train rolling stock. Structural advantages of the innovation freight cars are given. The complex systems of innovation car efficiency indicators providing the aggregate multiplicative effect of the growth of freight rolling stock performance are formed. The results of model calculations of rolling stock performance indicator variations depending on the operation of innovation gondola cars in freight trains for one production cycle are shown. CONCLUSIONS. Conducted researches and obtained modeling results show that operation efficiency of freight rolling stock should be considered taking into account the factors of positive influence resulting from the introduction of innovation cars.

PURPOSE. The article presents the results of experimental studies of variations in the steering, banking and trim angles of the vehicle when it moves in a circle crossing a single hump and the characteristics of shock absorbers are changed. RESULTS. The results of experimental studies are presented in the form of dependency graphs of the angle of vehicle steering, banking and trim when the vehicle moves in the circle and crosses a single hump and the technical condition of shock absorbers is changed. Operating diagrams and characteristics of shock absorbers are obtained using a dynamic test bench controlling operating parameters of suspension damping elements. CONCLUSION. The results of experimental studies of the process of vehicle crossing a single hump conducted in the same conditions allow to identify the dependence of the variation in the angles of vehicle steering, banking and trim with the change in the technical condition of shock absorbers. The parameters of the process of vehicle movement under the action of the centrifugal force and crossing a single hump characterizing vehicle stability can be used as diagnostic ones for a highly informative monitoring method of the technical condition of vehicle shock absorbers under operation.