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An assessment is given to the problems of urban wastewater sludge utilization in our country and abroad, with determination of formation and usage level. Global trends in the reduction of carbon dioxide emissions exacerbate the urgency of solving the designated tasks. At the same time, recently, in connection with the EU’s plans to introduce a cross-border carbon levy, it has become necessary to reduce the carbon footprint from burning traditional fuels, which is an urgent problem of modern society. One of the directions that provide a solution to this problem is the replacement of part of the hydrocarbon fuel by the consumption of multicomponent solid fuel based on the use of combustible waste that is part of the multicomponent fuel. This solid fuel can be used to meet the needs of small consumers, for example, in the autumn-summer period to generate a drying agent for the preparation of grain on the threshing-floor, in small boiler houses, in sand drying plants of locomotive depots, heat installations of hangars and workshops, as well as in other heat-generating installations operating on solid fuels. At the same time, solving the problem of reducing the carbon footprint for Belarus is closely related to another urgent task – reducing the energy component of industrial products and the environmental consequences of storing accumulated and generated waste. The paper presents the results of joint scientific research in the field of application of modern technologies and equipment using electrohydraulic treatment to reduce and minimize the level of anthropogenic and polluting substances in wastewater sludge. The described technological equipment, technology and post-treatment modes reduce the content of harmful substances in the wastewater sludge composition even with short-term treatment. An assessment of the effectiveness of the developed technology for the use of sewage sludge is given, using the method of wet multicomponent briquetting to obtain a multicomponent fuel. The presented process flow diagram of multicomponent briquetting using sewage sludge and plant-wood waste directly shows the undeniable advantages of using watered wastewater sludge as a raw material for the production of solid fuel. At the same time, the optimally selected ratio of components and moisture content of the briquetted composition solves a number of technologically difficult problems that cannot be realized using traditional briquetting technologies. The presented data of the conducted research and the developed technology make it possible to expand the area of using wastewater sludge as a secondary renewable material resource.

The paper describes method for reduction of NOx emissions by means of burning fuel with moderate residual incomplete combustion. Experimental results at two boilers are given in the paper.

The paper considers problems pertaining to quality control and analysis of electric power in networks of 1 kV and higher. It has been shown that in addition to periodical inspection of voltage transformers it is necessary to make diagnosis of their frequency characteristics. The paper proposes standards on frequency characteristics of voltage transformers and an automated method which has been tested in respect of real objects. The method makes it possible to execute diagnosis of frequency characteristics of voltage transformers directly on site of their operation and simultaneously with an inspection process.

The paper presents a criteria dependence for calculation of steam jet characteristics which is blown in cold water. Evaluations have been carried out and relations of technological and geometrical characteristics of steam-water injectors have been determined in the paper. The paper gives dependence evaluation of acoustic overpressure value and characteristic frequencies of injector’s «vibro-activity».

The paper contains an analysis of heat-and-mass transfer conjugated problem in case of moving of liquid melts in channels of metallic forms (moulds, dies, crystallizers etc.). Investigations of velocity profiles at various flow sections, current lines in the calculated area, pressure and viscosity fields in non-stationary state have been carried out in the paper.The paper reveals that current is of parabolic shape in the annular channel at rather large distance from a projection up and down the flow and pressure along channel section is practically unchangeable.The executed investigations of heat-and-mass transfer in the moving melt make it possible to create a data base of control parameters for development of prospective technologies of special casting methods.

The paper proposes a pack of applied programs intended for conjugate calculation of cycle parameters with heat exchangers of thermo-compressor loop and a calculation of irreversible losses in the loop binding including non-stationary operational mode is added to the pack.The paper contains investigations of thermo-compressor operation in the system of forced and exhaust ventilation for reduction of heat consumption by a heater in the cold season of the year

The paper considers problems leading to erosion wear of flowing part of a mean pressure turbine cylinder operating beyond critical parameters. Explanation of erosion wear of flowing part of a mean pressure turbine cylinder which is proved in practice and recommendations for wear reduction are given in the paper

The paper presents results of microclimate simulation that have been obtained while using the developed numerical model of heat transfer in the heated rooms. The model takes into account three types of heat transfer, namely: conductive, convective and radiant. The paper contains a qualitative and quantitative analysis of the obtained data. It has been revealed that type of a heating appliance significantly influences on distribution of microclimate parameters (air temperature and mobility, surface temperature) and level of heating comfort in the room.

Problems concerning optimization of a temperature diagram in respect of centralized heat supply systems with steam-turbine thermal power plants having mean initial steam parameters are considered in the paper. The paper shows that up-keeping of optimum temperature of heating water permits to increase efficiency of power-and-heat supply due to additional system economy of fuel.

The paper proposes a calculation method for electromagnetic parameters of single continuously long rod grounding electrode of tubular section at flowing of alternating current of mains frequency into the ground. The method is based on the Maxwell equations. The paper gives a distribution calculation of vertical and radial components of current density using finite differences.

The paper considers problems concerning optimization of a temperature schedule in the district heating systems with steam-turbine thermal power stations having average initial steam parameters. It has been shown in the paper that upkeeping of an optimum network water temperature permits to increase an energy efficiency of heat supply due to additional systematic saving of fuel.

The paper investigates influence of change in quality of superheated steam temperature regulations on service life of super-heater metal. А dependence between metal service life and dispersion value for different steel grades has been determined in the paper. Numerical values pertaining to increase of super-heater metal service life in case of transferring from manual regulation to standard system of automatic regulation (SAR) have been determined and in case of transferring from standard SAR to improved SAR. The analysis of tabular data and plotted dependencies makes it possible to conclude that any change in conditions of convection super-heater metal work due to better quality of the regulation leads to essential increase of time period which is left till the completion of the service life of a super-heater heating surface.

The paper describes analytical investigations that study relation of fuel combustion regimes with concentration values of sulphur anhydride in flue gases and acid dew point. Coefficients of convective heat transfer at internal and external surfaces of stacks have been determined in the paper. The paper reveals the possibility to reconstruct stacks while using gas discharging channel made of composite material on the basis of glass-reinforced plastic which permits to reduce thermo-stressed actions on reinforced concrete and increase volume of released gases due to practically two-fold reduction of gas-dynamic pressure losses along the pipe length.

An algorithm for selection of an energy efficient refractory lining has been developed on the basis of a ratio of summed-up capital expenditure and operating costs.A non-linear problem of thermal conductivity in a layer of the fiber refractory lining has been numerically solved in the paper. The paper determines an actuality of the fiber refractory lining application at the temperature level of 55–75 °C (on the average65 °C) on its external surface.A mathematical solution of a refractory layer selection has been executed in the paper. The paper gives several variants of the arrangement of three-layer fiber refractory lining.

The paper considers methods for testing electric power equipment with reference to power transformers and electric direct current machines by measuring complex of their parameters. The above-mentioned methods have been realized in the devices DST-1M and IPEM, respectively.An influence of inductive and capacitive elements included as components of low frequency filters in a measuring device on a value of an extra phase displacement between measured input currents and voltages being caused by them has been analyzed in the paper. The paper reveals that the extra phase displacement is initiated by oscillations of actual inductive and capacitive element values relative to their nominal values. Dependence of root-mean-square deviation of power measurement error due to phase displacement angle under load conditions at various tolerance values of the indicated elements and distribution of actual values of their nominal ones within these tolerances according to a normal low has been calculated in the paper

The paper contains commonly used and newly developed contactless forcing schemes in brake devices of asynchronous motors. Advantages and drawbacks of various contactless forcing schemes are presented in the paper. Conclusions are made in respect of prospective directions concerning development of contactless forcing schemes in brake devices.

A problem pertaining to determination of the concentrated exergy of the asphalt concrete mixture is considered in the paper. The paper shows the possibility to use the concentrated exergy of the asphalt concrete mixture for qualitative energy evaluation of mixing processes.

The paper presents methodical principles for analysis of opened 10(6) kV power network modes with symmetrical and asymmetrical phase loads. A mathematical model and an algorithm of sectional point optimization in the distributive 10(6) kV power network has been modified in the paper. The problem is solved with due account of power supply network of 110 kV and higher and a number of additional limitations. The obtained algorithms serve as a basis for development of the required complex of industrial programs for solution of technological problems pertaining to operation of urban 10(6) kV power networks.

The mathematical model has been developed and calculation of solid particle movement due to the action of swirling gas flow in a cylindrical element has been made in the paper. The paper investigates hydrodynamics of gas flow and forces influencing on a solid particle, both in the basic flow and during a contact with cylindrical surface. He obtained data can be used for research of processes pertaining to division of two-phase flows in a vortical device.

Development of a system for relay protection command transmission by high-voltage lines is shown in the paper. The paper describes an architecture of the system, main principles of its operation, engineering aspects of the development that is accomplishment of technical requirements, solution of trades-off. Justification of the selected design and an algorithm of the reliable detection of relay protection signals are given in the paper.

The paper presents the developed methodology that has been used for making calculations of main reliability indices for existing electric power supply circuits of AIC consumers. Some measures pertaining to provision of higher reliability are given in the paper. The paper contains calculations of changes in respect of reliability indices and reduction in cost of supply lost due to power supply interruptions in case of introduction of the proposed measures.

The paper presents an algorithm of signal processing against actual leakages simulated with the help of an experimental thermo-physical stand. The algorithm for evaluation of leakage coordinates has been developed in the paper and it is based on the signal processing which are received by every four microphone transducers. Higher accurateness has been achieved while applying an area method of local coherence.

The paper considers a power scheme and a control system of two-member frequency converter with voltage inverter which is designed for power supply of a bearing ring demagnetizer inductor. An algorithm for commutation of power keys is proposed in the paper. The algorithm makes it possible to obtain an inductor current which is close to the given current at low commutation frequency of power equipment. Simulation modeling within the system of computer «Mathlab Simulink» modeling has been applied with the purpose to evaluate the algorithm quality. The obtained charts of frequency converter electrical variables have shown practical coincidence of the given and actual currents that testifies about high efficiency of the proposed commutation algorithm. In addition to this an analytical expression for calculating filter capacity of demagnetizer inductor voltage inverter has been developed in the paper.

A correction factor that denotes an increase of heat transfer coefficient of a corridor tube bank at longitudinal pitch decrease is widely used in educational literature. The paper shows that such inverse relationship is not confirmed by the majority of scientific investigations. Additional experimental data are given in the paper. The correction factor for consideration of the influence of corridor tube bank geometrical characteristics on heat transfer is offered to be used in engineering calculations.

The paper contains results of the investigations concerning influence of symmetrical and non-symmetrical short circuits at main power network on electric power supply system of a huge oil terminal which is powered by own gas-turbine power station. Calculations have been made in accordance with the IEC and IEEЕ requirements. Estimations for voltage level and distribution of short circuit current in the electric power supply system of the Sangachal oil terminal being operated in parallel with the AzerEnerji grid are presented in the paper

The paper studies a cascade control synthesis for a two-mass electromechanical object. A cascade synthesis allows to determine a quick action of an electric drive speed regulation loop which is necessary for control of the specified mechanical part. A small parameter method is used in the paper. Calculative expressions for relations of loop frequency characteristics have been obtained in the paper. The paper presents a calculative example with the results of the system mathematical simulation.A synthesized system is characterized by robustness because variations in object parameters are acceptable if conditions of the system accessory to the given sets are observed.The proposed method can be applied if an own frequency of elastic vibrations is not very large in comparison with the characteristic frequency of the synthesized system.

The paper gives an analysis of power system in Vietnam. Data on power resources of the country and forecasts pertaining to production and consumption (oil, gas and solid fuel) up to 2020 are cited in the paper.

One of the systems applied for development of programmed logic controller (PLC) software is a CoDeSys programming complex. Its main purpose is to program a PLC and industrial computers in the IEC 61131-3 standard. As a means of PLC programming CoDeSys may be divided in two parts, namely: a programming medium and a programming system. The programming medium is to be operated using a personal computer in the Windows medium. The paper presents rather interesting tool for graphical laying-out of variable values which is used for adjustment of CoDeSys functions. The tool can be applied for adjustment of not only a personal computer but equipment as well even without writing a programme. Built-in visualization system being applied as in the tool medium so in the PLC (with display) and Web makes some operation more convenient. The given paper reveals CoDeSys capabilities using as an example that is a simulation of a D.C. engine control system with the help of proportional-integral-derivative controller

The paper presents main theoretical principles that serve as a basis for the developed numerical model of processes pertaining to conjugated heat exchange in the heated buildings. Information on functional capabilities of the developed programme, results of calculations and comparison of the obtained data with the conditions of heat comfort are given in the paper. It has been established that an application of simulation processes pertaining to energy and substance transfer at the design stage is considered as a rather efficient method for provision of the required parameters of a micro-climate and optimization of heat consumption by heated buildings.

The paper describes hydraulic tests of discharge capacity and pool conjunction in respect of dam spillway of the Grodno hydroelectric station. The process of ice passage through the spillway dam has been studied in the paper. The paper contains recommendations on safety depth downstream.

The paper contains an analysis of calculative dependences for steam-and-water injectors. Discrepancies in calculations and their reasons are shown in the paper. A model of acoustic pressure pumping being realized in the steam-and-water injector is formulated in the paper. The paper presents results of the experiment that qualitatively confirm the proposed model.

The paper describes a methodology based on the genetic algorithm that permits to automate the process for obtaining optimum rule bases while applying a controller based on a fuzzy logic. Using a specific structure of a chromosome, a special mutation operation and an adequate fitness function the proposed methodology makes it possible to select a fuzzy rule base, to minimize a number of rules, rationally to place input sets of fuzzy functions and corresponding arrangement of output singletons in the form of single-element sets. The paper presents an example when the methodology allows to reduce a number of rules by two fold and, consequently, calculative control procedure without any deterioration in quality control.

The paper describes conditions under which a single-mass model can be applied for system synthesis where elastic vibrations take place. This measure makes it possible to ensure the required indices of system quality without its structure complication. A small-parameter method is applied in the paper. A ratio of the required characteristic frequency of the synthesized system to own frequency of free vibrations of an elastic member is taken as a small parameter.The synthesized system is a robust (low-sensitive to changes of the object parameters) one. Results of mathematical modeling prove the possibility to ensure acceptable indices of quality and robustness of the synthesized system.

The paper considers a mathematical model for pulsation process of underwater gas explosion products in a half-close cylindrical rigid chamber during gas-impulse regeneration of filters. Second-order differential equation with constant coefficients has been derived. A special calculation program has been developed to solve the equation. The paper proposes formulae for calculation of pressure impulse, maximum velocity and dimensions of gas cavity during expansion process.

The paper considers an impulse structure of gas flow in low-frequency pulsating layer. An influence of pulsation frequency on layer resistance is taken into account in the paper.

The synthesis of a positioning system using a combined position regulator is given in the paper. The paper describes a technique of calculation and forming an input /output position regulator characteristic.A special simple unit for an automatic adjustment and diagnostics of the position regulator with a variable structure is proposed in the paper. This unit practically solves a problem pertaining to complexity and labour-consuming of combined position regulator adjustment.

The paper considers problems pertaining to limitation of heating extraction load of power-and-heat supply turbo-generators with the purpose to obtain a reserve power.Graphical dependences for determination of time period within which an indoor temperature is decreased by 1 оС according to relative heat expenditure for heating and a value of outdoor temperature. The paper reveals the possibility to limit a heating load by 20% within some hours time while observing comfortable indoor conditions.

A modified method for simplified calculation of the first maximum tension occurring in the conductors of split phase at short circuit has been developed in the paper. The paper contains evaluation of simplified calculation reliability while using calculative experiment in accordance with FAZA computer program and experimental data of foreign researchers. Graphs for determination of conductor bending angle while calculating maximum tension have been obtained in the paper and they permit significantly to accelerate the process of calculation.

A specified model and algorithm for optimization of slit points in a distributive 10 (6) kV electrical network with due account of supply network of 110 kV and higher have been developed in the paper. In order to determine loss values in supply network a special mathematical model of the closed network has been constructed and the model permits to execute the given operation with minimum computing expenses. The paper proposes and analyzes methods for registration of task limitations: damage due to insufficient supply of electric power, possible network overloads for permissible currents, power supply provision for the 1st category consumers, prohibition against switching in public network and switching-on of sectional apparatus being switched-off according to normal scheme.

The objective of a crane control system is to ensure movement of a load with minimum load swing. A classical Proportional-Derivative (PID) controller is not the best solution of this problem due to the non-linear system. The paper presents a designing procedure of fuzzy logic controller on the basis of fuzzy logic and theory of a rough controller. Comparative indices of both controllers obtained as a result of digital modeling are given in the paper.

The paper presents results of investigations pertaining to developed technological scheme on combined production of chemically desalted and softened water without usage of soda ash for deposition of hardness salt. Scheme application limits in its two operational modes have been determined and mathematical expressions for determination of the main operating conditions have been derived in the paper.

Transformation of territories contaminated by radionuclides, actinoids, heavy metals and other harmful substances into power-generating valleys for production of pure bio-energy carriers is considered in the paper. The transformation process consists of three stages. The paper shows that the transformation of Belarussian territories contaminated as a result of Chernobyl accident into power-generating valleys will make it possible not only to provide our country with pure bio-energy carriers but also to make them import goods.

A brief analysis of operational characteristics of current protection with various current-time curves of distributive network lines with unsoldering is given in the paper. The paper considers possible measures directed on better technical modernization and expansion in the field of application of multi-stage microprocessor current protection in distributive networks with one-side power supply.

The paper considers possibilities and limitations of various methods for obtaining power re-serve at power-and-heat supply turbo-generator sets.Approximate values of specific heat rate and quantity of reserve power and rate of its obtaining for various turbine plants are given in the paper.

The paper considers peculiar features of thermochemical decomposition of peat as a result of quick pyrolysis. Evaluation of energy and economic expediency of the preliminary peat decomposition process for obtaining liquid and gaseous products has been made in the paper. The paper reveals prospects pertaining to application of the given technology while generating electric power and heat.

The paper considers an operation of a metallic recuperator under conditions of heat exchange surface drift with scale and soot deposits. It has been shown that after one-year of its operation heat transfer factor decreases by 100–200 %. The paper contains recommendations for selection of a metallic recuperator.

The paper considers necessity and possibility of a transformation of polluted territories of Belarus, the Ukraine and Russia to ecologically-safe systems by radionuclides, actinoids and hot particles. The real possibility of the problem solution while applying special plants-hyper-accumulator is shown in the paper.

The paper considers a thermodynamic efficiency and peculiar features pertaining to realization of heat-recovery steam-gas plant schemes with steam reheating. Possible reserves of higher efficiency concerning plant economy and methods for achieving these goals are given in the paper. The author has made calculations for steam-gas plants of one-, two- and three-loop cycle of steam pressure. An analysis of the obtained results in respect of technical and economic indices and expediency of the application of corresponding plants in power engineering of the Republic of Belarus are presented in the paper.

The paper investigates an operation of a self-oscillatory asynchronous electric drive with impact loading in the form of a bell. A mathematical model of the electric drive and a circuit of winding connection of the asynchronous engine for its operation in a self-oscillatory mode have been developed in the paper. Analytical investigation of the mathematical model has been carried out and time diagrams of bell bowl and tongue movement have been constructed.

The paper considers problems pertaining to mathematical modeling of a transformer substation with protected electric power lines. It is proposed to use systems of dynamic modeling for investigations applying a method of calculative experiment with the purpose to evaluate behavior of protection and automation at short circuits. The paper contains comparison of results obtained with the help of program-simulated complex on the basis of a complex mathematical model of an object and with the help of dynamic modeling system – MathLab.