The purpose of the paper is development of methods and tools for modeling compact power lines of increased throughput capacity. The methods of finding electric power system modes based on phase coordinates are used. In their turn, the phase coordinates are based on the models of elements in the shape of grid equivalent circuits with the fully meshed topology. These models and methods are implemented in the Fazonord-АРС software complex, which provides the modeling of electric power system steady-state modes and determination of electric field intensities. The electric field is created by power transmission lines of various designs. The paper presents the results of modeling the modes and electric fields of 220 kV compact overhead lines with horizontal wire arrangement. For comparison, similar calculations have been performed for a typical 220 kV power line of a typical design. The modeling results allowed to formulate the following conclusions: active power losses in a compact power line reduce significantly under the same total cross section area of the wires of compact and typical power lines. For example, when the transmitted power is 375 MW the losses in a compact power lines decrease by 45 % as compared with the typical 220 kV power line. A lower asymmetry is observed at the receiving end of a compact power line. The compact power line provides better conditions of electromagnetic safety. The electric field intensity at the height of 1.8 m is 1.5 times lower for the compact power line axis than the similar index of a typical power line. The fall of the magnetic field intensity in the same point reaches up to 60%.

The article provides a comparative analysis of the topologies of the power supply networks in Italy and Eastern Siberia: the average degree of nodes, the average path length, the average clustering coefficient, the density of the graph, the distribution of the degree of nodes and the correlation coefficients of the centrality measures. The theory of complex networks is used to analyze the networks. The analysis has revealed the similarity of these networks characteristics and structure. It is shown that the network data are not described by the model of classical random graphs and are not scale-free. The correlation of centrality measures for these networks has been studied as well. It is revealed that the nature of the correlation is similar for both networks, it indicates the similarity of their logical structures. In addition, this means that the degree of consistency of node ranks obtained by different centrality measures will be approximately the same. Therefore, a similar efficiency of the method can be expected for the Eastern Siberia network. Since the electrical power supply networks in Italy and Eastern Siberia have a similar topology, the method of critical object identification will be effective for both networks.

The paper addresses the possibility of using renewable energy sources for mechanical plant power supply. The area climatic conditions are given an assessment. The possibility to install alternative energy facilities at the plant is studied. Solar panels are proposed as alternative sources. The required equipment is selected and the calculation of the number and capacity photovoltaic cells is made. Conducted technical and economic calculations serve the basis for efficiency evaluation of installed photovoltaic cells. The purpose of the paper is to evaluate the effectiveness of alternative energy facilities integration into the power supply system of an industrial enterprise. The computation of the solar panel true power is made taking into account the table of solar insolation. The number of solar modules, inverters and other equipment connected to them has been calculated based on the area of building roofs. The economic effectiveness is estimated on the basis of the calculated payback period of the installed equipment. Assessment of Irkutsk climatic conditions has shown that the area under investigation has a relatively high potential for the development of solar energy. Therefore, this work gives a detailed consideration of the integration of solar modules into the power supply system of the industrial enterprise. Their actual power, which directly depends on solar activity and averages 80% of the capacity rate, is calculated. The calculated annual amount of power received from solar panels has showed that renewable energy facilities can make a significant part in enterprise power supply. According to the estimates obtained, the economic effectiveness of their use today is quite low. However, trends in reducing the cost of the solar panels themselves and other auxiliary equipment, as well as growth of electrical energy price make these power sources effective in the near future. The conducted study clearly shows that it is quite possible to integrate alternative energy facilities into the power supply system of an industrial enterprise, and they will be able to make a significant part of its power consumption. In view of expected drop of equipment costs and growth of electricity prices, the renewable sources will become cost-effective.

The purpose of the article is to improve the machining efficiency of parts made of aviation materials through the application of specialized and special designs of end mills with soldered-on hard alloy helical plates. The study employs the experimental and theoretical research methods of improving the performance of specialized and special designs of mills with soldered-on hard alloy plates for aviation material machining at the stages of their design and production. The methods of designing specialized and special designs of end mills with soldered-on helical plates for milling aviation materials both for rough work and finishing treatment are developed. Recommendations are given on their manufacture. Application of calculation methods allows to eliminate the influence of subjective factors on the quality of designing and reduces its labour intensity. Application of specialized and special mills with soldered-on hard alloy helical plates in the range of their diameters from 20 up to 60 mm ensures the efficiency of both rough work and finishing treatment of parts made of aviation materials. They are especially effective at finishing treatment as they shape the machined surface without the distortion of shape unlike the mills equipped with disposal inserts located in several rows on height. Mills with variable cutting patterns are most effective for rough work. They create a smaller level of dynamic loads on the technological system that is especially important when machining not rigid parts made of the materials with low values of elasticity coefficients.

Electric discharge machining is shown to be the best method developed and used for drilling precision micro-holes. High-performance piercing of micro holes with non-rigid requirements to hole surface accuracy and quality requires to use laser and electron-beam methods. The methods of casting and assembly are used to obtain super deep micro holes with the depth of 100 or more diameters. A comparative scientific and technical analysis of the world industrial technologies of obtaining micro holes in the historical development forms the methodological basis of the research. The article gives a physico-technical characteristic of ten methods of micro hole drilling, describes the equipment used and process capabilities the methods under discussion. The quantitative and qualitative assessment of technological processes is given as well. The rational application fields of ten methods of micro hole drilling are determined. The promising directions of improving the precision micro hole technology are developed.

Purpose - to determine consistent patterns of parameters influence to processing by radial and face polymeric abrasive brushes on intensity of their pile’s wear at details rounding edges. Researches were conducted experimentally on various granularity radial BB-ZB Type C and Type A, and face brushes BD-ZB of the company 3M, by weighing brushes before processing and after processing. In article is considered influence of cutting speed and brush deformation on their wear intensity. It is established that with increase in these parameters also the wear of brushes grows. It correlates with the same regularities of cutting forces change from speed and brush deformation. The regression equations are received in the second degree polynoms form of the wear dependence of the cutting speed and tool deformation for radial and face brushes. Tables and schedules are offered for determination of worn-out pile length taking into account actual state of brush wear convenient for use in the practical purposes. Polymeric abrasive brushes are very effective at sharp edges rounding of details from various materials. Especially when processing lengthy details, for example, in aircraft construction and helicopter engineering. By optimization of edges processing by criterion "the prime cost minimum" one of factors influencing the choice of optimum processing parameters is the cost of the worn-out tool on performance of this operation. Knowledge of wear intensity regularities of the tool allows to successfully solve the problem of process optimization.

The purpose of the article is to consider the current development trends in the engineering analysis of non-rigid elements on the example of the operating principles of ANATOLEFLEX with assemblies containing the components made of composite materials. The assemblage of assemblies from non-rigid components requires the simulation of complex statistical tasks at different levels of assembly to automate the control and monitoring of gaps. The performed review has allowed to reveal the advantages of the ANATOLEFLEX platform, which allows to take into account the assemblage sequence of typical assemblies, the properties of composite or other types of materials, the type of production process and contact modeling used to build a complete and realistic assembly model. The application results of this solution are represented by the Airbus aircraft assemblies, which employ the analysis of simulation results. It has been found out that the use of the realistic simulation of assembly models such as the analysis of tolerance simulation or calculation of the gap map for shimming up gap process adjustment to a large extent enables automation of the design of the assembly with composite material components.

The purpose of the paper is to develop a pilot crosshead-free piston power machine with improved cooling of compressed gas and better mass-dimensions. The work uses the modern methods of designing reciprocating compressors and pumps. A new promising design of a crosshead-free piston power machine with improved cooling of the compressed gas and better mass-dimensional parameters has been developed on the basis of the analysis of the existing designs of reciprocating hybrid power machines intended for simultaneous compression and movement of gas and fluids. Using the basic approaches to the design of reciprocating compressors and pumps, the main design dimensions of the parts and assemblies of the crosshead-free hybrid power machine have been determined. A new design of a crosshead-free piston power machine is proposed. It has improved cooling of the compressed gas and better mass dimensions. Using the basic principles of design techniques for reciprocating compressors and pumps, the main design dimensions of the machine have been determined. The Solid Works software package was used to develop the assembly drawings. Conducted dynamic and strength calculations of the main parts and assemblies have confirmed the correctness of the selected materials and dimensions.

Dimensional deviations arising in mechanical assemblies result from the change in the shape, orientation or position of assembly geometrical elements. If these deviations occur between the mating surfaces of assembly components they affect the final result of the assembly. One of the main conditions of successful assembly and assemblability is accounting for these deviations as early as the design stage of assembly units. The purpose of the article is representation of the general approach for the formalized description of permissible spatial tolerances of assembly unit geometrical elements. The study employs mathematical modeling using the biquaternion theory. A new approach has been developed for formalized imaging of the fields of assembly unit geometrical tolerances using the mathematical apparatus of biquaternions. Configuration manifolds of orientation and position tolerances are built and classified. Biquaternions used to describe permissible spatial deviations of assembly unit geometric elements enable comprehensive description of these deviations and consideration of their correlation. The constructed configuration manifolds allow to take into account the permissible spatial tolerances of assembly units at the stage of geometric design.

The purpose of the work is to study the possibility of reducing leakages in the seals with metal O-rings (on example of a vacuum flange joint of the ConFlat standard) by ion-plasma sputtering deposition of a soft metal on the ring surface. The coating was applied using an original ion-plasma source with a liquid anode. The hermeticity of sealing o-rings of the CF40 joint was tested on an ultrahigh vacuum test bench with a XT-100M mass spectrometer quadrupole gas analyzer tuned to control the in-leakage of helium in the test bench vacuum chamber. Conducted experiments allowed to determine that the amount of in-leakage decreases under the reusing of a sealing ring sputtered with a copper coating. Ring surface micrographs were obtained using a scanning electron microscope. Sputtering deposition of a soft metal layer on the contact surfaces of a single-used metal ring restores surface sealing properties as well as reduces in-leakage as compared to a new liner. The effect is provided by the formation of a tight contact of the flange wedge solid metal with the surface of the plastic coating leveled along the entire circumference, which was restored by smoothing ring cavities formed during the previous tightening of the flange joint.

The purpose of the research is to compare some computer programs used for the simulation of foundry processes including alloy casting. Magmasoft, Poligon, SolidCAST, PROCAST computer programs are used for the comparative analysis. Several foundry samples of the various degree of complexity are used for the simulation. The performed computer simulation in the PROCAST system allowed to eliminate the drawing defects identified in the original model. A 2D and a 3D grid networks were built. They improved the quality of the casting mould and made it multifunctional for both a casting and a casting mould. Foundry simulation results in PROCAST program have been received. The obtained results suggest the software system PROCAST to be the most efficient computer program for foundry process simulation of all tested.

Ball mills are used in the production of building materials. In the process of operation the equipment degrades, pivot pins as the main components of mills wear out losing the cylindrical shape of their working surface. To restore pivot pins an add-on machine-tool with a rotary cutter is used. It allows to perform on-site machining. A mathematical model including a set of technical limitations is developed. The input parameters and the target function are described. Using a linear programming method, the optimal values of the cutting modes are found. The rational values of the cutting modes when pivot pin machining in the period of its repair are found to optimize the restoration process. The method of linear programming is used. The area of optimal region of technological parameters of pivot pin cylindrical surface rotary machining with the use of the add-on machine-tool in mill restoration is obtained.

The article deals with the transients of a synchronous machine with allowance for its magnetic system saturation. A method of numerical simulation of synchronous machine transients is proposed with the possibility of taking into account the asymmetry of stator winding and magnetic system. The asymmetry arises if the synchronous machine is damaged, in particular in the case when inter-turn short circuits occur in the stator winding. The study uses a direct solution of the differential equations of emf equilibrium and voltage drops in windings in phase coordinates together with the rotor motion equation. In this case, the contour of each phase winding of the stator is described by a separate equation. Different phase parameters can be taken into account as well. The mathematical model of a synchronous generator operating into an active-inductive load is implemented in the software package MATLAB. The model takes into account one of the possible types of asymmetry: it is an unequal number of turns in phase windings. This enables the modeling of interturn short circuits without allowance for the occurance of additional short-circuits. The effect of damper windings on the transient caused by a sudden short circuit in the system is accounted. It is compared with the damper winding-free model. The simulation results are analyzed taking into account the saturation of the machine magnetic system. The obtained results allowed to draw a conclusion about the adequacy of the implemented model.

The purpose of the article is to provide a mathematical model for the automated pressure selector (APS) designed on the basis of a deadweight pressure gauge tester as a measuring basis of an automated deadweight pressure system for quality control of absolute pressure sensors. The research uses the methods of automated control theory, system modeling, and the basic principles and postulates of gas dynamics. The results of theoretical research of airflow processes with continuous pressure differentials through the throttling sections of the automated pressure selector are presented in the mathematical model. The main parameters of gas dynamic processes occurring in a closed volume where the absolute air pressure is set are determined. It is found that the value of the set absolute pressure mainly depends on the design characteristics of the APS, i.e., on the parameters of the free piston, which performs the functions of both a regulating and sensing element of the automatic pressure control system within the APS. This allowed to implement the fundamental principle of pressure measurement in the automated pressure selector. Considering the results of the theoretical researches of airflow issues and APS design features, a mathematical model of the automated pressure selector has been developed allowing to describe dynamic processes occurring in closed volumes with the precision required for designing of automated control systems. The proposed mathematical model is reduced for calculations and can be used for designing of automated deadweight pressure system for quality control of absolute pressure sensors where modern control methods can be implemented.

Development of a software package for calculating and operation analyzing of large district heating systems under state control. Theory of hydraulic circuits. Graph the ory. System research in energy. Multilevel modeling. The method of nodal pressures for the calculation of hydraulic conditions. Computational Mathematics. Linear Algebra. Methods of non-linear programming. Information Technology. The analysis of the directions of centralized heat supply systems (HSS) development in Russia and in a number of countries of northern Europe is made. Types of HSS operation conditions are classified, as well as goals and tasks of their calculation at different stages of control. Adaptation of the mathematical model for the solution of the adjustment calculation problem and thermal-hydraulic conditions analysis and the features of its implementation are proposed. The functions and properties of the developed information and computing complex "ANGARA-HS" are described and its differences from analogues are analyzed. The questions of the relevance of the construction of multi-level computer models of hierarchical structure HSS for the problems of calculating conditions are examined. Possibilities of graphical analysis of a priori information and calculation results by means of the developed tool are explored. Automation of control, increase of reliability, economy and quality of HSS operation require the introduction of modern mathematical modeling methods and information technologies. Calculation of thermal-hydraulic condition is a necessary element for assessing the feasibility of decisions taken at all stages of control. An information and computer complex "ANGARA-HS" of the fourth generation was developed to solve traditional and new problems from the analysis and control of large HSS conditions.

The purpose of the work is to select an optimal decision-making method under various conditions and software implementation of the method. The set purpose is achieved through the use of a comparative analysis of decision-making methods including the hierarchy analysis method, Delphi method and brainstorm method. It was required to find a universal method of decision-making with the possibility to generalize the opinions of independent experts identifying contradictions in judgments and taking into account the influence of the "human factor". The conducted analysis allowed to identify and summarize the advantages and disadvantages of each method. The "Brainstorm" method meets all the requirements least of all due to the large influence of external and internal factors on expert decisions. The optimal decision-making method that meets most of the requirements is recognized to be the hierarchy analysis method. The uniqueness of the method is determined by the fact that it is both qualitative and quantitative, it is confirmed theoretically and practically, it is suitable for solving both simple and complex problems and takes into account the "human factor". The hierarchy analysis method is justified axiomatically and is confirmed by the necessary and sufficient number of theorems that transform it into a mathematically grounded approach for obtaining the scales of preferences in solving complex and important problems. This paper gives a mathematical description of the hierarchy analysis method and the stages of its software implementation. The mathematical apparatus of the hierarchy analysis method allows to decompose the investigated problem into components, sort them into levels, as well as logically order the judgments (parameters are compared in pairs with determining the preference degree of one parameter over another) and give them a quantitative evaluation in the form of a response that represents a set of priorities for the relative importance of alternatives.

The given work deals with the analysis of the development possibilities of transport systems of large cities and urban agglomerations. It focuses on the tools for forming an optimal topology of the agglomeration transport network. The paper formulates the formation sequence of the graph of the large city transport network that operates on the basis of rail transport, high-speed urban highways and traditional public transport interaction. The purpose of this work is to develop the theoretical foundations for the formation of the optimal graph of the city transport network under high motorization conditions, whereas the urban network operation is based on rail and wheeled transport interaction. The following methods of scientific analysis are used: dialectical, comparative economic and statistical, system, system-functional and historical-genetic analysis, economic and mathematical modeling, management theories of organizational and economic systems and the method of scientific abstraction. Complex application of these methods allowed to ensure the reliability of the conducted research. The paper formulates an algorithm for forming the graph of the agglomeration transport network. The criteria of the quasi-optimal graph of the urban transport system are developed, specified and justified. The need for multilevel structures in the integrated topology of the transport system and their role in the formation of the integrated efficiency of large city transport system operation is shown. The author formulates, substantiated and described the formation features of agglomeration transport clusters and determination of their relationships. The feature of the current development stage of transport systems of cities and agglomerations is the tendency of a significant excess of the application flow for communications (both from motorists and users of public transport) over the capacity of the system. This determines the need for a comprehensive solution, which consists in the transformation of the city transport network topology and the construction of its optimal graph formed taking into account the existing and future interaction of wheel, rail and other possible kinds of transport. In this case, the formation of the centers of gravity of places together with the existing real estate development and the existing infrastructure will form a system of transport clusters of agglomeration. Thus, the formation of an effective multi-level graph of the agglomeration transport network is necessary in terms of ensuring the optimality of the entire agglomeration development.

This article describes the effect of pedestrian crossings on the roundabout capacity. Recently there is a tendency to use roundabouts instead of crossroads with traffic light regulation, since ring intersection has significant advantages, especially during the periods between rush hours. The balance of traffic flows has a significant impact on the performance of the roundabout. During the field surveys traffic jams were recorded. Their concentration was particularly high at the entrances and exits of the observed roundabout. Comparison of empirical data with the figures given in the regulatory documentation for the design of roundabouts, showed the need to design a two-level roundabout. Information on correspondences at the intersection was processed for further use in the simulation model. To assess the traffic situation and the impact of pedestrian flows on it, the roundabout model was constructed. The main parameter for assessing the performance of this road network section was the delay time of vehicles when passing through the intersection. The simulation was carried out in three different scenarios: the roundabout with and without traffic lights as well as the complete absence of intersecting pedestrian and traffic flows. The results of roundabout`s computer simulation confirmed the presence of big traffic delays on this section of the road network, which were caused, among other things, by the pedestrian crossings located in the close proximity to the roundabout`s entrances and exits.

The paper deals with the positive and negative effects of road bump installation on the roads within human settlements. The road bumps are widely used today as the elements of forced limitation of traffic speed in the road network in order to improve traffic safety. They are mainly installed close to pedestrian crossings, in the places attracting a large number of people; schools, kindergartens, hospitals, shops, markets, shopping malls, as well as in the yards and residential areas. The research uses the method of observations and statistics. The latter provides an overview of artificial road bumps including the history, operation, effect on traffic speed, environmental impact, and general price comparison. The study of artificial road bumps allowed to reveal the dependence of the vehicle driving style and negative effect of artificial road bumps on both the traffic speed and environmental indicators. The obtained data show that road bumps have more disadvantages than advantages. Their use in the road network of residential areas lead to the increased emissions of exhaust gases and toxic substances contained in them; to increased wear of tires and brake linings of vehicles, whereas the wear products can remain in suspension for a long time. Moreover, the installation of artificial road bumps reduces the service life of many vehicle parts and assemblies. The alternatives to road bumps are cameras with video recording, traffic lights equipped with a button as well as underground and aboveground pedestrian crossings.