PURPOSE. The paper studies the influence of specific types of converters and filters in the measuring part on the operation of the mathematical model of numerical transformer differential protection. METHODS. The method of oriented graphs is used for the development of mathematical models of protection, which are formalized in the form of programming codes using the C programming language. The MATLAB Simulink software complex is used as a platform for created models and codes integration. RESULTS AND THEIR DISCUSSION. The presented results demonstrate the operation of the specific elements of the mathematical model of the numerical transformer differential protection and their effect on the operation of protection as a whole. Some features of MATLAB Simulink have been revealed which must be taken into account when implementing mathematical models in this complex. CONCLUSIONS. It is shown that complete and reliable modeling of numerical relay protection requires rather to have an idea on structural element types and characteristics than to reproduce their functions. Otherwise, the adequacy of the mathematical model will be low. The known problem of the numerical methods for solving the stiff systems of differential equations is relevant even for such small (in mathematical terms) models as mathematical models of relay protection.

PURPOSE. A pneumatic conveying device capable to provide continuous and uniform transportation of the additive in the form of dehydrated carbonaceous slime from the tank into the air duct is developed. When designing a pneumatic conveying installation it is important to choose the most optimum geometrical sizes of the installation elements, the most rational physical parameters including gas flow velocity in the channels of pneumatic conveying installation and pressure at the inlet and outlet openings necessary for efficient operation of the pneumatic conveying system. METHODS. The research is conducted in the hydrodynamic program module SolidWorks Flow Simulation. Numerical model operation is carried out through the solution of differential equations of motion and continuities. A two-parameter k-ε turbulence model is used for the closure of the set of equations. RESULTS AND THEIR DISCUSSION. The article presents the results of computer simulation and the analysis of the influence of the number of outlet openings of the distributing device (which is a nozzle analog by the operation principle) on pressure losses in the pneumatic conveying installation and on pneumatic conveying efficiency. CONCLUSIONS. It has been determined that efficient transportation of finely divided material from the cylindrical tank requires the use of the pneumatic conveying installation with a distributing device having 4 outlet openings.

The PURPOSE of the paper is to extend the functional capabilities of the magnetron sputtering technology when machining the substrates of complex geometry. METHODS. Laplace’s equation is used to determine the distribution nature of magnetic field components in the retuned magnetron sputtering system (RMSS) with the target of final sizes. RESULTS. The theoretical relationships of magnetic field components in RMSS are given depending on RMSS parameters and movement speed of the target cathode. CONCLUSION. The prospects of this method of magnetic field calculation in RMSS gaps under sputtering (processing) of long substrates of complex geometry (for example, gas turbine engine blades) is shown when using vacuum ion-plasma treatment.

PURPOSE. A complex of automatic equipment has been created and is being tested. It is designed to provide the normal and emergency mode control of the stand-alone power supply systems with distributed generation that operate in parallel with the centralized electrical network. Automatic control of the objects with small generation operating in parallel with the network requires the solution of the identification problem of their state classes. METHODS. The proposed solution method of the specified problem is based on the identification of the main structural and mode properties of district power systems and their representation in the form of logical variables and equations. It is universal and does not depend on the facility circuit. RESULTS AND THEIR DISCUSSION. The paper presents a logical basis of the identification algorithm of the state classes (structural-mode state identification) of the district stand-alone system of power supply used by an automatic operator. The reasons and criteria for the classification of the system states are proposed as well as a mathematical model for class state determination. The solution of the identification problem of state classes has been demonstrated on example of a stand-alone power supply system of a residential district, which is built on the basis of a cogeneration gas-piston power plant. Solution of the problem has been verified using an emulator program. CONCLUSIONS. Innovative automation equipment for small generation with an automatic operator ensuring parallel operation of a district stand-alone power supply system with the centralized electrical network are expected to be implemented in a pilot project at one of the energy facilities of the city of Novosibirsk. This will significantly (by several times) reduce the cost of connecting such objects to the network and improve their efficiency reducing losses in networks.

PURPOSE. The study deals with the development of the theoretical bases of the dynamics of commutator contact group elements. The dynamic interaction of the brush and commutator in the conditions of vibration loading of the traction motor body is discussed. METHODS. The feature of the study is consideration of a possible loss of the unilateral brush-commutator contact as a result of vibration effects of internal and external forces. The method of mathematical model construction based on the use of the generalized function of the gap and considering unilateral constraints is proposed. The first stage of mathematical model construction allows for the possibility of computational scheme reduction to material particle interaction with a vibrating surface in the gravitational field. The model under investigation takes into account non-standard force factors through the introduction of the additional semi-permanent force applied to the brush. RESULTS AND THEIR DISCUSSION. The impact of force factors on continuous gap-forming modes of brushes is shown. The analytical conditions reflecting the interaction features of the brush in the interval of rise and fall on the commutator surface are formulated. The results of numerical simulation of force factors for periodic losses of contact with continuous brush tossing are presented. CONCLUSIONS. The developed mathematical model of the commutator element interaction using the function of gap allows to take into account the possibility of contact loss in the complex forms of brush and commutator interactions and can find application in the development of control devices of brush and commutator surface contact modes.

The relevance of the work is determined by the fact that the significant number of developed designs and wide application range of downhole jet pumps does not always provide the operation efficiency that meets necessary requirements. Therefore, the execution of works on the study of effective operation conditions of jet systems at the construction stage of oil and gas wells, as well as the valuation of their manufacturing requirements, maintenance and repair at oil and gas enterprises is an immediate problem. The PURPOSE of the work is to improve the application efficiency of downhole jet pumps in oil and gas well drilling. METHODS. The study involves mathematical modeling of the process with the use of the laws of mass conservation and continuity and the amount of fluid flows. RESULTS. The dependence of jet pump characteristics on its wet end roughness has been determined.

The PURPOSE of the paper is to study the influence of deformation kinematics on the quality characteristics of the hardened part surface layer including roughness, residual stresses, mechanical hardening depth, hardness and microhardness. METHODS. The characteristics of the surface layer of hardened parts have been experimentally determined using modern equipment: a profilograph-profilometer Form Talysurf i200, a hardness tester HBRV 187.5, a microhardness meter PMT-3, a device Xstress 3000 G3/G3R, a metallographic microscope MET-2. RESULTS AND THEIR DISCUSSION. The experimental studies allowed to find out that surface plastic deformation by a two-radius roller has a number of advantages in the quality of the hardened layer as compared with a single radius roller. For example, surface roughness decreases by 3-3.5 times, surface layer hardness increases by 6-8%, residual compressive stresses in the surface layer increase by 1.2-1.5 times. CONCLUSIONS. The results of experimental studies allow to choose the method of hardening in order to obtain specified quality characteristics of the surface layer of machine parts. The obtained results can serve the basis for the development of combined methods of surface plastic deformation ensuring high quality of the surface layer by a number of parameters.

PURPOSE. Continuous mixing technological equipment is widely used in industry, construction engineering and agriculture. Some mixers alongside with rotatory motion of actuators also employ reciprocating motion (oscillation) in order to improve the quality of mixtures. The purpose of this work is to identify the possibility of improving these machines performance through increasing their kinematic parameters. METHODS. A design model of a two-shaft mixer has been developed in the course of study. It allowed to perform a mathematical modeling of kinematic and power parameters of the mechanism. RESULTS AND THEIR DISCUSSION. The relationships between the kinematic, dynamic and geometric parameters of the mixer mechanism are analyzed. The dependences of axial and tangential loads on the ratio of velocities, as well as axial velocity and acceleration on the ratio of velocities are obtained. CONCLUSIONS. The axial velocity has the greatest value when the rotation angle of the eccentric equals 180° and the acceleration is 120 or 240°. To reduce actuator’s dynamic loads it is necessary to use such high-speed modes, under which the acceleration varies insignificantly, i.e. in the interval of the velocity ratio from 0 to 0.2. The study results show that the increase in the ratio of axial and tangential velocities increases the tangential load and decreases the axial load on the working shaft blades.

The PURPOSE of the article is to study the possibility of wolframite concentrate processing eliminating cake leaching tailings from charge composition while reducing the sintering temperature and obtaining a commercial tungsten trioxide. METHODS. Processing of wolframite concentrate was performed by its sintering with soda, saltpeter and potassium carbonate. The obtained sinter was crushed and subjected to leaching with the production of the solution of sodium tungstate. Measurements of sodium tungstate density allowed to determine its concentration and calculate the forecast extraction of tungsten trioxide. The resulting solution of sodium tungstate was decomposed with the precipitation of “artificial scheelite”, which was decomposed by the hydrochloric acid in order to produce a tungsten acid. The latter was subjected to thermal dissociation to obtain tungsten trioxide. RESULTS. Having conducted a series of laboratory studies on wolframite concentrate processing it was found that the components of charge are to be sintered at the temperature of 450-500ºC at 1:0.45:0.9:1 ratio of wolframite concentrate, soda, potassium carbonate and saltpeter respectively. The powder of tungsten trioxide with a high content of valuable component has been produced. CONCLUSION. The possibility of wolframite concentrate processing with the elimination of cake leaching tailings reducing the tungsten content in the charge from charge composition was studied. The optimal temperature conditions of sintering and the composition of charge to be sintered in order to obtain sodium tungstate were determined. Leaching of the resulting sodium tungstate with the following precipitation of the “artificial scheelite” and the decomposition of the latter by hydrochloric acid allowed to produce the powder of tungsten trioxide with 99.8% content of WO₃ .

PURPOSE. Electroflotation recovery of manganese from industrial water allows to treat water effectively and use it in a closed water supply system as it provides a high extraction degree of metal cations. METHODS. Integrated treatment of technogenic manganese-containing hydromineral resources provides the possibility to obtain additional scarce products from the non-metallic parts of waste. RESULTS AND THEIR DISCUSSION. The paper shows the optimization of electrocoagulation extraction of manganese from the industrial waters of a processing plant. Sludge resulting from the industrial solution treatment is a valuable material that mainly consists of hydroxides of aluminum(III), iron(III) and manganese(II). Its simple processing allows to extract mixed coagulants widely used for water purification and a scarce manganese dioxide used in the production of chemical sources of current. CONCLUSIONS. Electrochemical purification and integrated processing of formed electrocoagulation sludge allows to obtain more than 30 tons of manganese dioxide and 150 tons of mixed coagulants for water purification.

Operation of diesel power plants can be improved through the organization of in-place diagnostics by vibration parameters. The PURPOSE of the work is to develop a method of digital processing of diesel vibration signals taking into account engine features as an object of analysis. METHODS. The methods of fast Fourier transform, common-mode accumulation and averaging, frequency filtration and phase strobing have been used to identify a useful vibration signal and determine diagnostic parameters. RESULTS. Substantiation is given to the obtained diagnostic parameters of vibration signals generated by diesel dynamic processes. CONCLUSIONS. A method has been developed to obtain diagnostic parameters of diesel digital vibration signals including frequency and amplitude of the peak values of power spectral density that correspond to the dynamic processes in the diesel engine. Conducted test of diesel 2Ch8,5/11 operation assessment has showed a 4% error of the method.

Purpose. Analysis of variance and regression analysis are ones of the most important methods of mathematical and applied statistics. The purpose of the article is to present both approaches specifying their similarities and significant differences. Methods. Mathematical and statistical methods have been used to achieve the set purpose. Results and their discussion. The analysis of variance and regression analysis are demonstrated on the example of solving the problem of time of day-dependent simulation of average traffic speed over the Glazkov Bridge in the city of Irkutsk. For this purpose a single factor analysis of variance and a corresponding regression analysis with dummy variables have been carried out. Introduction of a new qualitative explanatory variable -weekday/day off allowed to conduct a two-factor analysis of variance and built a corresponding regression model. The use of the factor “general level of traffic congestions on Irkutsk roads” allowed to construct a regression model describing the effect of both qualitative and quantitative factors on the average travelling speed of traffic over the Glazkov Bridge. Conclusions. The similarity and difference of the variance and regression approaches to the analysis of data have been shown on the specific example. The results obtained through the analysis of variance can be reproduced in the analysis of the regression model where the influence of qualitative factors is described using dummy explanatory variables.

PURPOSE. The paper deals with the circuits ensuring PON reliability indicators presented in ITU-T Recommendations G.983.1, G.983.5, G.989.1 and updated circuits of ITU-T G.983.1 recommendations. Analysis is given to the following economical circuits ensuring reliability indicators: “neighboring protection”, a single ring, a dual ring and hybrid topologies based on the use of “tree” and “ring” topologies. The presented protection circuits are compared. METHODS. Given the structure of each protection circuit, structural reliability diagrams are developed and unavailability factors are calculated. Calculations are performed using the mathematical program MathCAD. RESULTS AND THEIR DISCUSSION. The lowest unavailability factors are obtained for the networks using protection circuits of types C and D1, since these protection circuits provide for the duplication of all network elements. If PON without protection is not taken into account, the highest unavailability factor is predicted for the networks using the type A protection circuit. This is due to the availability of backup of the backbone cable only. CONCLUSIONS. When using some or another protection circuit the operator can provide the required level of the reliability indicator PON and LR-PON. However, when designing and deploying a network the future operating costs should be evaluated in addition to capital costs.

The PURPOSE of the study is search for new and modernization of known generation methods of random processes with specified static (probability distribution law) and dynamic (correlation function) probabilistic properties. METHODS. The main research methods used in the study are the probability theory, mathematical statistics and numerical methods. RESULTS. The object of the study is a permutational technology of random process generation with a simultaneously specified probability distribution law and an autocorrelation function. This technology is simple in software implementation, has high response speed and allows to introduce the required probability properties with the accuracy of their reflection, sufficient for engineering applications (e.g. in simulation modeling). The Bernoulli (binary) law is taken as a law of probability distribution of the generated process. The conducted analysis of the probabilistic properties of the behavior of the permutation procedure components has resulted in the identification of new, previously unknown functional capabilities of this method of random process generation. Probabilistic properties (probability distribution laws and autocorrelation functions of the candidate vector components) are systematized depending on a mathematically justified permutation variant. The study is given to two variants of the permutational method that allows to generate a periodically correlated binary process. It is proved that these variants simultaneously provide the possibility to generate a two-dimensional binary random process. CONCLUSION. Conducted theoretical studies allowed to expand the functionalities of the permutational procedure of binary random process generation due to the possibility to generate a two-dimensional random binary process.

PURPOSE. The paper deals with the methods of obtaining sparse solutions based on the least square support vector machines (LS SVM). METHODS. The sample is split into the training and test parts in order to obtain a sparse solution. A sequential algorithm is given to receive the training and test parts of the observation sample using the method of D -optimal experiment design as applied to the LS SVM method. We also present the sequential algorithms of sample splitting into parts using the consistency criterion. To testify the operation efficiency of the proposed sample splitting method a computational experiment is conducted where the solution accuracy by LS SVM is improved through adjusting of the scale of the Gaussian kernel function. This parameter of the kernel function is selected by minimizing the prediction error on the sample test part. Finally, the accuracy of the obtained solutions is tested by the mean-square error. RESULTS AND THEIR DISCUSSION. The computational experiment was performed on simulated data. A nonlinear dependence on the input factor was selected to be a data generating model. The variance of noise (noise level) was determined as the percentage of the signal strength. Three methods of sample splitting into the training and test parts including replacement, rejection and inclusion of points into the training part have been compared. The cross-validation method has been used to select the parameters of the LS SVM algorithm. CONCLUSIONS. The results of conducted computational experiments have shown that a sparse solution by the LS-SVM method can be obtained through the use of the sample split into parts using the D -optimal experiment design.

The PURPOSE of the article is to review the researches in the field of multi-agent technologies for the period from 2005 to 2016. In the first place the analysis was given to the articles covering the application issues of multi-agent technologies in various fields and object domains: logistics, security, information retrieval, risk management, health care, etc. with the focus on the works dealing with the issues of using multi-agent technologies ensuring security in technosphere. The need for the use of multi-agent systems (MAS) for solving the issues of security management in technosphere first of all is determined by the complexity of modern systems and organizations. This makes the centralized management inefficient due to the presence of large information flows. METHODS. Having performed a comparative analysis of the conducted studies, the main software tools used for the development of multi-agent systems have been identified and the application feasibility of multi-agent technologies for solving technospheric safety problems has been determined. ANALYSIS RESULTS. It has been revealed that most studies except for a small number of works do not contain program implementation, that is, they haven’t moved further than the theoretical level. Nevertheless, the authors of these publications have made a significant contribution to the development of the theory of agent approach. The present article outlines the promising directions of further studies of multi-agent approach application in the field of technosphere safety.

The PURPOSE of works in this direction is development of a network of small remote control airdrome devices. METHODS. The known calculation methods of the main operation performances of wheeled running gear in a traction mode are used taking into account the operation similarity of wheeled haul tracks and road construction machinery. The capabilities of the developed small-sized tow and the adequacy of the chosen method are estimated and tested in the full-scale tests with the use of the comparative analysis of the obtained experimental and theoretical traction characteristics. RESULTS AND THEIR DISCUSSION. A new aircraft towing method using a small remote control tow is proposed. It allows to achieve a maximum technical and economic result. Loading of the nose gear on the towing tractor frame eliminates the use of the additional ballast for towing and saves fuel at the idle run of the towing machine in aircraft maintenance. CONCLUSIONS. The proposed towing method using a small remote control tow has a number of advantages over the regular means of towing.

PURPOSE. This paper deals with the development prospects of transport systems in large cities and urban agglomerations. The paper defines the key features of urban agglomeration in terms of transportation provision, identifies the differences between the transport system of the city and agglomeration. The purpose of this work is to identify the main efficiency criteria of transport system development in large cities and agglomerations in order to develop the recommendations for optimizing the trajectories of their controlled evolution. METHODS. Such methods of scientific analysis as dialectical, comparative and economic, statistical, system, system and functional, historical and genetic are used in the study together with the economic and mathematical modeling, the theory of organizational and economic systems management and the method of scientific abstraction. Their complex application allowed to ensure the reliability of the conducted research. RESULTS AND THEIR DISCUSSION. Based on the conclusions of a number of researchers dealing with the operation efficiency of urban transport systems, we have synthesized different points of view, conclusions and theoretical assumptions on the formation of urban transport system efficiency into the model of the integrated efficiency of transport system operation in a large city. The work also considers and classifies the factors that have a significant influence on the operation efficiency of the urban transport system. The author has formulated, justified and described the optimality criteria of urban agglomeration transport system development. CONCLUSIONS. Agglomeration features the presence of diverse transport networks in its composition - they are the transport systems of many communities and settlements included in the agglomeration and stochastically formed in many respects. Therefore, urban agglomerations comprise the areas with a higher degree of economic activity concentration and the areas with a lower level of capital concentration. As a consequence, the criterion of area capitalization must be taken into account as a part of the criteria for the development and managerial decision-making on laying or transformation of a highway (branch of a line) of the urban agglomeration. A consequence of this criterion is the need to form an effective graph of the transport network agglomeration in terms of ensuring the development optimality of the agglomeration as a whole.

PURPOSE. This paper proposes a procedure for determining an optimal structure of the urban passenger transport rolling stock that will enable to achieve the highest possible quality parameters of transport service considering the restrictions of economic efficiency of transport organization operation. METHODS. Formation of the optimal structure of the rolling stock is reduced to the problem of determining the rolling stock capacity and traffic intensity for each route in such manner as to achieve the minimum coefficient of dynamic use of capacity in the route network. This also takes into account the mutual influence of routes and implements imposed restrictions of economic efficiency represented in the number of transported passengers per one kilometer. RESULTS. The mathematical model introduced in the article is implemented in the form of the algorithm of the directed search for the variants of the program of passenger transportation within the route network. The efficiency of the proposed algorithm is illustrated on the example of an abstract network of two interacting routes. Being applied in practice, the proposed procedure will determine a transportation program in the route network, which will ensure the best quality of transport service for the existing tariffs and volumes of budget subsidizing of the system of municipal passenger transport. CONCLUSIONS. This article presents a mathematical model determining traffic intensity and rolling stock capacity for each route of urban passenger transport in order to ensure the best possible quality parameters of transport service in the network of interacting routes when implementing the restrictions on the economic cost-effectiveness of transport organizations. The efficiency of the problem-solving algorithm is proved on an abstract network of two interacting routes. The quality of transport services is assessed using a coefficient of rolling stock capacity that is one of the main indicators that determines the trip comfort. The economic cost-efficiency of routes is estimated on the basis of the number of passengers per one kilometer of travel.

PURPOSE. The article deals with the results of works on mechanization and automation of the technological processes of magnetic monitoring conducted in order to reduce the influence of a human factor on the reliability of non-destructive flaw detection and increase the labour productivity of critical flaw identification. METHODS. A magnetographic method using a magnetic tape as a sensitive element for flaw recording is proposed in order to improve the application efficiency of the non-destructive quality control of rolling stock parts with the complex shape of the monitored surface. RESULTS. A number of developments has been performed dealing with the control tools and technological documentation. They allow to simplify the magnetization and magnetic recording when conducting magnetic tape testing of large tanks, e.g. railroad tank cars. The novelty of technical solutions is confirmed by the author’s certificates and a patent. CONCLUSIONS. Application of the magnetographic monitoring with pulse magnetization by the developed methodology greatly simplifies technological operations and increases detectability of such critical flaws as cracks at their early stage.