• Energy Research
• other engineering and technologies close
• UA close
• GB close
• Russian close

The article shows the advantages of using modern electronic learning tools in the training of specialists for the mineral and raw materials complex and considers the basic principles of organizing training using these tools. The experience of using electronic learning tools using foreign teaching materials and involving foreign professors is described. A special attention is given to the electronic learning environment of the Cisco Networking Academy Cisco NetAcad. The experience of teaching at the Networking Academy of the Saint-Petersburg Mining University is described. Details are given to modern virtual environments for laboratory work, such as Cisco Packet Tracer, GNS3 and Emulated Virtual Environment. The experience of using electronic learning technologies at the University of Economics of Bratislava is considered. It actively cooperates with a number of universities of other countries, such as the University of International Business (Almaty), the Eurasian National University named after LN Gumilyov (Astana) and the Institute of Social and Humanitarian Knowledge (Kazan). В статье показаны преимущества использования современных средств электронного обучения при подготовке специалистов для минерально-сырьевого комплекса и рассмотрены основные принципы организации обучения с использованием этих средств. Описывается опыт использования средств электронного обучения с использованием зарубежных учебно-методических материалов и привлечением иностранных профессоров. Особое внимание уделяется рассмотрению среды электронного обучения Сетевой академии Cisco Cisco NetAcad. Описывается опыт преподавания в Сетевой академии Санкт-Петербургского горного университета. Подробно рассматриваются современные виртуальные среды для проведения лабораторных работ, такие как Cisco Packet Tracer, GNS3 и Emulated Virtual Environment. Рассмотрен опыт использования технологий электронного обучения в Экономическом университете Братиславы, который активно сотрудничает с рядом университетов других стран, таких как Университет международного бизнеса (Алматы), Евразийский национальный университет имени Л.Н.Гумилева (Астана) и Институт социальных и гуманитарных знаний (Казань). №4 (226) (2017)

This research aim is to develop a method for modeling the conditions for the critical hydraulic impacts emergence on thermal and nuclear power plants’ pipeline systems pressure pumps departing from the general provisions of the heat and hydrodynamic instability theory. On the developed method basis, the conditions giving rise to the reliability-critical hydraulic impacts emergence on pumps for the thermal and nuclear power plants’ typical pipeline system have been determined. With the flow characteristic minimum allowable (critical) sensitivity, the flow velocity fluctuations amplitude reaches critical values at which the pumps working elements’ failure occurs. The critical hydraulic impacts emergence corresponds to the transition of the vibrational heat-hydrodynamic instability into an aperiodic one. As research revealed, a highly promising approach as to the preventing the critical hydraulic impacts related to the foreground use of pumps having the most sensitive consumption (at supply network) performance (while other technical characteristics corresponding to that parameter). The research novelty refers to the suggested method elaborated by the authors’ team, which, in contrast to traditional approaches, is efficient in determining the pump hydraulic impact occurrence conditions when the vibrational heat-hydrodynamic instability transition to the aperiodic instability.

The article considers mathematical approach to environmental quality management to improve the ecological comfort of living for the population. The problem of environmental management is described using a multi-factor model of quality of the environment with the weight coefficients of the importance of its components: atmospheric air, acoustic impact, soil, water resources, and green spaces, accessibility of natural and recreational areas. The values of weight coefficients of importance of influencing factors for environmentally comfortable living are determined by the method of expert assessment. A multi-factor model is used for detailed assessment of the ecological quality of the urban environment. The proposed quantitative approach also allows to compare the environmental comfort of the different residential districts or to study the dynamics of environmental comfort of specific urban area. Much attention is paid to scientific and methodological principles of management and the formation of the concept of «environmental quality». The strategy of environmental management with ecological foundation of various practical solution is shown. The plan of measures on organization of optimal management of quality of the environment to improve comfort of living for the population of the residential microdistrict of Tiraspol is presented. Graphical scheme of the results of integral analysis of various environmental indicators and assessments for improving the comfort of the environment is given. Realization of environmental quality management of the urban areas on the basis of a multi-factor model contributes to the gradual change of dangerous ecological conditions of environmental factors, to increase a comfort of the territory taking into account the real preferences and needs of the population.

The purpose of this article is to develop a method and algorithm for the calculation of the steady-state mode and static characteristics of the squirrel-cage asynchronous motors that are supplied by a three-phase network with an asymmetrical voltage system. The aim is achieved by developing a method where the mathematical model of the motor takes into account the saturation of the magnetic core and the current displacement in the short-circuited rotor bars. Magnetization characteristics of the main magnetic flux and the leakage fluxes paths are used to account for the saturation. To account for the current displacement in the rotor winding the bars are divided into several layers throughout the height, resulting in a number of windings on the rotor with mutual inductive couplings. In the mathematical model, the processes in the asynchronous motor are described by a system of the nonlinear differential equations of electromagnetic equilibrium, composed in the fixed three-phase coordinate axes. The solution of this system in the steady-state mode is the periodic dependence of the currents, which are determined by solving the boundary problem. For this purpose, their algebraization is carried out by approximation of the periodic dependences at the nodes’ grid of the period of repeatability of the process by the third order splines. The solution of the problem is to determine the nodal values of coordinates on the period from the obtained nonlinear system of algebraic equations. For this purpose, the continuation method and iterative refinement by the Newton method were used. Calculation of the static characteristics was performed by the differential method.

The aim of the work is to increase biogas output and generation of electricity in biogas plants due to the joint fermentation of cattle manure with winemaking waste. To achieve this goal, the following tasks have been solved: the biogas yield from cattle manure with winemaking waste was determined during periodic loading of the digester; based on the obtained experimental data, a mathematical model was calibrated to estimate the biogas yield during fermentation of cattle manure with the addition of winemaking waste. Because of the studies, it had been found that when manure was fermented with part of the water replaced in the substrate 2% of the winemaking waste, the fermentation dynamics in the substrate are similar to the fermentation of pure cattle manure. Biogas obtained by fermentation of manure with the addition of 2%, 6.5% and 13% of wastewater from wine production instead of water in the first day of fermentation either did not burn at all or burned poorly. The addition of winemaking waste to a substrate based on manure in an amount of 13% allows increasing the maximum biogas yield by a third to 1,372 l/(hrkg dry organic matter). The significance of the research results lies in the fact that the use of winemaking waste as a substrate will allow a third increase in biogas output and power generation, and a reduction in the payback period of a 4,4 MW biogas plant using the green tariff to 6,5 years.

The results of gas current calculations in a flow part in not reversive jet-reactive turbine at pressure upon an input to the turbine up to 10 МPа (earlier calculations were spent up to 0.9 МPа), executed in program complex FlowVision for the first time are presented in the article. The dependences of factors and parameters of efficiency of the jet-reactive turbine (JRT) from total pressure upon an input in the turbine are received. They are exposed in a graphic type. The primary goals of the research were: calculation of parameters of current of gas in a flow part of the jet-reactive turbine by means of program complex FlowVision at pressure upon an input of the JRT from 0.4 up to 10 МPа, the analysis of results of calculation, reception of dependences of different factors from total pressure upon an input in the turbine. The Influence of total pressure on an input in the JRT on various factors, such as: total pressure recovery factor, factor of hydraulic resistance and factor of outflow were investigated. It was discovered that total pressure recovery factor  increases for 27 % at an increase of pressure of an input of the jet-reactive turbine up to 4 МPа. It was determined that the hydraulic resistance factors related to the dynamic pressure at the inlet ξin and the turbine output ξout is reducing at 2.7 and 3.3 times, respectively, with an increase in pressure at the inlet of the jet- reactive turbine to 4 MPa.

The aim of this work is the development and study of a mathematical model of the floating dock initial stability for solving problems of list and trim stabilization. The proposed model allows calculating the change of the parameters of the initial stability of the floating dock (with and without a vessel) for different values of the draft. The initial stability of the real floating dock of the middle class with a carrying capacity of 8500 tons is studied using the simulation model developed by the authors in the FREE!SHIP Plus. With the help of this computational model, the operation of immersion of the floating dock is considered. At each stage of immersion at a certain draft, the parameters of the initial stability of the floating dock are calculated, namely, the values: transverse and longitudinal metacentric heights, centers of buoyancy, centers of gravity, and mass displacement. Corrections of transverse and longitudinal metacentric heights due to changes in the mass of liquid in ballast tanks and the influence of its free surface are also taken into account. Based on the obtained modeling results, the following dependences are calculated: a) moments from list and trim angles at different values of draft, b) moments of list and trim from draft at various values of list and trim, c) angles of list and trim from the fill level of the respective tanks. These dependences can be used for further development of the list and trim stabilization system for the given floating dock.