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Copyright of Bulletin of the L.N. Gumilyov Eurasian National University. Technical science & Technology series is the property of L.N. Gumilyov Eurasian National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The scale of land pollution with oil waste necessitates the use of economical and effective methods of recultivation. Phytoremediation is one of the simplest methods, but it has a number of limitations, so additional preparation of the territory is often required before it is carried out. Preliminary electrical preparation and subsequent seeding of special phytoremediants are of interest. Passing a constant electric current through the soil volume under a low voltage removes toxicants from deep soil layers even with flooding. In addition, it reduces pollutant content in the upper layer, where the plants root system is located, which creates more favorable conditions for phytoremediants. Adequately selected types of plants will ensure additional soil cleaning, improve its structure and air exchange. The results of two research directions are presented. Experiments on the study of plant resistance to oil-contaminated soil substrate allowed establishing contamination thresholds at which it is advisable to sow a particular species, and to choose optimal phytoremediants. The study of the oil-containing soil cleaning in a monocathodocentric electrochemical installation with the fixation of main characteristics (oil products concentration, soil temperature, volt-ampere characteristics) allows us to develop technical measures to prepare territories for phytoremediation taking into account the relief features.

In this work, for the first time, samples of nanoparticles of the multicomponent AlCuNiCoCrFe alloy were obtained by the method of joint electric explosion of wires of Al, Cu, Ni metals and N06003, NiCo29-18 alloys in an argon atmosphere. As the basic mode of wire explosion, a mode close to the matched one was chosen, which made it possible to minimize the influence of the energy of the arc stage of the discharge on the structural-phase state of the forming nanoparticles. It is shown that the obtained samples are represented by spherical particles with sizes ranging from 15 to 500 nm. The number-average size of nanoparticles of the obtained samples varies from 40 to 58 nm. The particle size distribution is described by a normal-logarithmic law, the crystal structure of the particles corresponds to substitutional solid solutions with a bcc and/or fcc lattice. An increase in the Al content in the explosion products leads to an increase in the content of the phase with a bcc lattice in the samples, while an increase in the Cu content leads to an increase in the phase with a fcc lattice. The resulting samples can be used in electrocatalysis.

Copyright of Renewable Energy / Vidnovluvana Energetyka is the property of Institute of Renewable Energy of NAS of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background. The study is devoted to the issue of improving the accuracy of automated measuring instruments for the electrical parameters of oxide coatings. In measuring instruments, integrating circuits based on an operational amplifier, which is a universal amplifying device, are used to perform linear mathematical operations on analog signals. The disadvantage of the integrating circuit is the use of an operational amplifier, when using which it is necessary to take into account many parameters and factors that can affect the output signal, and hence the accuracy of the measured value. Materials and methods. Methods of indirect measurement of voltage and current on the studied sample with an oxide coating using the proposed structures of measuring channels are presented. It is shown that the parameters of operational amplifiers have a significant influence on the additive and multiplicative errors of measurement results, for the analysis of which a linear model of an operational amplifier is considered. Results. Based on the metrological analysis of the voltage measurement channel on the test sample, formulas for estimating additive, multiplicative and nonlinear error components are obtained. The contribution of multiplicative and additive parameters of the operational amplifier to the error of measurement results is analyzed in detail. Conclusions. Metrological analysis of the equivalent circuit of an operational amplifier with feedback has been performed, which can be used to estimate additive and multiplicative errors of circuits based on operational amplifiers widely used in instruments and measuring systems. It is shown that the total relative error of the developed channels for measuring current and voltage does not exceed 0.5%, which makes it possible to measure these values of the studied oxide coatings with guaranteed accuracy.

Relevance of the work is related to the fact that currently the technological processes of exploration, extraction, transportation of geo-resources in the oil, mining, coal, chemical and other industries are subject to a high level of mechanization and automation involving electric machines. The reliability and trouble-free operation of these machines depend on the state of the winding insulation, the role of which is played by the insulation of the windings of electric motors. Reliability indicators of this element of the windings are laid in the process of their production. At the same time, a significant contribution to the mentioned indicators is made by the technological operation of impregnation. The probability of hiding defects in the insulation of the windings, thermal properties of electric motors, moisture resistance and solidity of the windings depend on how well this operation is carried out. Therefore, the improvement of impregnation and increase of its efficiency are very topical. The purpose of the work is to create a mathematical model of the technological operation of impregnation with the use of electrostatic charging of the impregnating composition jet; to show that it is possible to reduce the level of induced voltage used for electrostatic charging of the impregnating composition jet by strengthening the electric field in the nozzle area, from which the frontal parts of the winding are watered with impregnating composition, by giving the nozzle a certain shape. Methods. When creating a mathematical model, classical methods of solving differential equations describing electromagnetic fields were used, and experimental studies made it possible to establish the adequacy of the created model. Results. The results of modeling and research of a new technology of impregnation of windings of electric machines with an electrostatically charged jet of impregnating composition are presented. A mathematical model was developed linking the field gain at the top of an ellipsoid nozzle with its geometric parameters. The experimental verification of the obtained model was carried out and the adequacy of the model to the experimental results was shown. The data of practical application of the obtained model on real factory installations are presented, showing the real possibility of reducing the voltage level at the nozzle and the effectiveness of the proposed impregnation of the windings. The advantages of the proposed technology are shown in comparison with typical impregnation technologies based on the data obtained in real production. The proposed technology will significantly reduce the likelihood of factory defects due to winding circuits in the windings, will increase the reliability of manufactured electric motors in the process.

THE PURPOSE. To consider issues related to the study of methods for determining the sources of violations of the quality of electrical energy in power supply systems, in particular consumers which create rapid voltage changes or voltage fluctuations that create rapid changes in the luminous flux in electric lighting installations. Show that electrical receivers with a sharply variable operating mode are sources of fluctuations in the consumed current and voltage in the electrical network of power supply systems, which in turn manifests itself in the form of unacceptable values of one of the indicators of the quality of electricity - flicker, defined as the subjective perception of fluctuations in the luminous flux of lighting devices. To study the possibilities of determining the places of occurrence of significant voltage fluctuations without the use of expensive and complex instruments for measuring flicker values in the electrical network. To develop a simplified method for determining the locations of electricity consumers that negatively affect the operation of electric lighting systems and, ultimately, the vision of personnel. Conduct a check on a computer model of a simplified method for determining the places of occurrence of voltage fluctuations that are inadmissible in their magnitude, which are expressed in the appearance of significant doses of flicker that exceed the standard values.METHODS. Solving the problem, a computer model was used, created in the Simulink extension package of the Matlab scientific and technical calculation system.RESULTS. The article describes the relevance of the problem, discusses the quality of electricity in power supply systems. It has been shown using experimental data that in electrical networks there is an excess of the standard values of flicker doses. The possibility of using interharmonic components of the mains voltage to determine the sources of unacceptable doses of flicker is considered. A simplified method for finding flicker sources based on obtaining the values of the derivatives of currents at various points of the electrical network is presented. Computer simulation of an electrical network diagram with electrical receivers, which have both calm and sharply variable nature of work, has been performed. It is shown that the use of the values of the derivatives of the current at various points of the electrical network makes it possible to identify the sources of the occurrence of unacceptable doses of flicker.CONCLUSION. The occurrence of significant rapid voltage changes in the electrical network negatively affects vision, which is inevitably accompanied by increased personnel fatigue and can lead to industrial injuries. The results obtained by the authors of the article show that it is possible to use it to determine the places of occurrence of large voltage fluctuations, which are manifested in unacceptable doses of flicker of the derivatives of currents. It should be taken into account when conducting surveys of power supply systems in order to use fairly simple hardware to identify sources of disturbance in the quality of electrical energy.

The article presents the research results on a device for automatic measurement of the temperature stability of the output characteristics of voltage-to-frequency converters. The device can be used to measure mechanical stresses in the ship's hull. The main source of information on the state of the mechanical stress on the hull of the ship is the integrated monitoring system. Monitoring methods are based on measuring the frequency of the output signals from the sensors based on strain gages, which have a wide scatter of values for parameters and characteristics and depend on external factors. A possible solution to this problem is to use a device that would convert the analog sensor signal into a more noise-immune signal of another type, for example, voltage-to-frequency converter. It is for such systems based on synchronous integrated converters that the authors have developed a device for automatic measurement of the temperature stability of the output characteristics of frequency converters. Such device can measure the thermal stability of the convertor automatically, which makes it possible to analyze the effect of temperature on the output characteristics of the converter and to experimentally study the sensors in a wide range of operating temperatures (from room temperature to 70°C). The study of the thermal stability of the characteristics of such sensors made it possible to confirm the quality of its electronic components and to determine which parameters need to be adjusted. The device is a set of units, one of them being a control circuit based on the ATmega-16 RISC microcontroller. This design and the developed algorithm for the device operation makes it possible to determine the output frequency with a high accuracy (with a measurement time of 1 sec, the accuracy reaches 0.05%). The developed device allows finding the ways to increase the thermal stability of mechanical stress sensors based on integral converters.

Voltage dips are quite frequent and dangerous phenomenon, which can lead to disruption of the production process. Ensuring the stability of induction motors during voltage dips is an important task to ensure the continuity of the technological process, as well as to reduce material losses. THE PURPOSE. List the main causes of voltage dips. Develop a simulation model corresponding to a typical power supply scheme for an oil pumping station with a group of asynchronous motors as a load. Perform two series of calculations to determine the parameters of the electrical mode in case of voltage dips and the subsequent restoration of the voltage on the buses of the supply substation. METHODS. When solving the problem, the PSCAD software package was used. RESULTS. The article describes the relevance of the topic, the main causes of voltage dips are given. The simulation of voltage dips resulting from a short circuit on the substation equipment has been performed. A series of calculations were performed, differing from each other in the changed initial data: the place of occurrence of a short circuit, the time delay of automatic transfer of the reserve. The analysis of the obtained results is carried out. CONCLUSION. According to the test results, it can be seen that the decrease in voltage on the low voltage buses of substations after the operation of automatic transfer switch is the lower, the longer the time delay of automatic transfer switch. In this work, the maximum time delay was 7 seconds, while there was no violation of the stability of the induction motors. The need to study the operation of a group of asynchronous motors in case of accidents in an external electrical network is also determined.

The paper gives an analysis of perspectives for development of wind power generation, information on the share of wind energy in electricity generation in the world and in Russian Federation is provided as well. Data on gross, technical, economic potential of wind energy of Russia and the Murmansk Region has been presented. When calculating the gross wind energy potential of the region, data from the last 10 years of observations carried out at 37 meteorological stations have been used. The territory of the region has been divided into 6 distinctive zones, based on the wind activity. Gross energy potential has been calculated for each zone: for the heights of 10, 50, 100, and 150 m. Gross wind energy potential of the region at the height of 150 m has thus been estimated at 23,090 billion kWh. The Murmansk Region's 201 MW Kola wind farm, which consists of 57 Siemens Gamesa SG 3.4-132 wind turbines with a unit capacity of 3.465 MW, is to be constructed by 2021 under the direction of Enel Green Power. Wind energy potential and annual power generation of the Kola wind farm have been assessed. The difference between the obtained results and calculations of Enel Group's specialists amounts to less than 15 %. For the cases of relocation of Kola wind farm to different wind zones, the annual power generation of the wind farm has been estimated. It has been determined, that in case of Kola wind farm's relocation to the zone with the highest wind activity its annual electricity generation could be increased up to 1.5 times. A model of the Kola energy system has been developed in NEPLAN software, its validity has been proven. The calculations of the wind farm's operation modes show that voltage levels of the system nodes and powerflows are within the boundaries defined by normative documents. The effectiveness of reactive power regulation of the wind farm has been shown.

Copyright of Nanosistemi, Nanomateriali, Nanotehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction. A significant proportion of earth faults in medium voltage networks represents a short-lived and transient process. Problem. In such cases, earth fault protection that responds to steady-state current and voltage is not able to operate properly. Purpose. To develop earth faults protection selective algorithm using transient components, that occur in zero-sequence currents and voltage in the fault process. Method. A mathematical model of the power supply system was applied to study the transient components of currents and voltage of zero sequence in compensated electrical networks with phase-to-earth faults, and a those model also is used to test the operation of the developed protection algorithm. The results showed that, the reactive power for transient components, of the frequency greater by 4-6 times, than fundamental frequency, which are extracted from the current and voltage of zero sequence by wavelet transform in compensated electrical networks on the damaged feeder, is positive regardless of the degree of compensation of the capacitive current. That may be the basis of the principle of directional protection. Originality. Phase-to-earth fault selective protection algorithm has been developed. In that algorithm, first derivatives of currents and voltages of zero sequence are found, to reduce the influence of aperiodic components. And then, by using of the wavelet transform with Morlet mother function, an orthogonal components are extracted from them. Reactive power is calculated for transient component. If that reactive power excess of threshold, the relay will make a decision. The reliability of the developed protection algorithm is confirmed by the results of mathematical modelling and verification of the test sample at the laboratory stand and by means of field signals that were recorded by digital loggers at the substations.

The relevance of the work. Such spheres of human activity, as geological exploration, production, transportation and recycling use the means of mechanization and automation with application of different types of electric drives. The reliability of these devices is determined by winding insulation quality. In this regard, the search for effective means of controlling wire enamel insulation, improving the insulation quality, eliminating technological reasons of defect occurrence are popular and topical. The aim of the work is to research the influence of defect meter parameters, modes of control and gas-discharge defects flowing in a primary converter on accuracy of measuring the geometrical sizes of defects in wire insulation. Methods: oscilloscope, micrometer, theory of planning the experiments, methods of correlation estimates between the control parameters and regression analysis. Results. The author has revealed and stated in the paper the regularities of occurrence of systematic error in measuring defect extent when controlling wire isolation at winding, by the defectiveness meter using the gas-discharge sensor as the primary defect converter. It is shown that two factors: control U voltage on the defect gas-discharge sensor and the time constant τ= RC of the sensor discharge circuit, influence most of all the value of the specified errors. Using the correlation and regression analyses the adequate model of systematic error was constructed; it was established that the wire motion velocity has no significant effect on the magnitude of this error. When applying the theory of planning the experiments the author obtained the adequate equation based on bias from the control settings. The paper demonstrates the practical application of the established patterns to improve the accuracy of controlling the defect extent in wire insulation in gas sensor meters.

Subject of Research. The paper presents a technique for simultaneous measurement of the radiation energy spectrum and the electrical parameters of a high-current pulsed arc discharge. The proposed approach provides the calculation of the energy and power parameters of the discharge and the efficiency of electric energy conversion into radiative one in different spectral ranges. Method. The energy efficiency of flash lamps was calculated by two separate methods: the measurement of gas discharge electrical parameters and detection of radiation energy spectrum. The electrical parameters were measured by assembling a circuit using a coaxial non-inductive shunt and three mixed-type voltage dividers combined with their earth terminals at one point for fall-of-potential measurement on the lamp and capacitor. The combining of earth terminals made it possible to register simultaneously the voltage drop at different points without the risk of oscilloscope failure. By the mathematical multiplication and integration, the energy and power characteristics of the circuit and the pulsed gas discharge were obtained. The radiation characteristics measurements were carried out by applying a spectrometer and calibrated photodiode radiation detector. The spectral distribution of the radiation source was obtained and radiation efficiency was specified in the chosen wavelength intervals. By calculating the radiation energy in the spectral range corresponding to the applied task and taking into account the previously obtained values of the dissipated energies in the circuit and discharge, the radiation efficiency is found in the selected wavelength ranges. Main Results. On xenon flash lamp example with 5 mm internal diameter and arc length of 120 mm, oscillograms of the current and voltage drop on the capacitor and lamp were obtained. The calculated radiation efficiency values in the spectral ranges of 200-250, 200-300 and 200-400 nm were 2.7, 9.3, and 28 %, respectively. Practical Relevance. The proposed method gives the possibility to register simultaneously the current and voltage drop on several sections of the discharge circuit and radiation characteristics, and eliminates the necessity to take into account the instability of these parameters from pulse to pulse. The calculation of the radiation efficiency in any wavelength range included in the spectral interval of the spectrometer sensitivity enables the designers of systems with flash lamps to optimize the discharge circuit based on the radiation requirements of specific applications.

To determine the results of the transmission of electrical energy through the power line from the source to the consumer, it is necessary to have accurate information about the parameters of such line. Determining these parameters for operating lines with a minimum error is quite a laborious process. But if a researcher is interested only in voltages and currents at the end and at the beginning of a homogeneous section of a three-wire transmission line, then it is sufficient to use the theory of multipoles. In particular, the theory of eight-poles. The article presents the method of experimental determination of the longitudinal and transverse parameters of the studied transmission line. The study used the methods of natural experiment using an appropriate fleet of electrical devices, and methods of indirect measurement of the desired parameters. The experiment consists of six stages; on the basis of the obtained data, it becomes possible to determine the numerical values of the main parameters of the studied section of power transmission lines, with which it is possible to establish a quantitative relationship between the input and output characteristics of electrical energy. In addition, the described method, in principle, can be applied to the analysis of active eight-terminal networks of a similar design. This means that the proposed methodology can provide a comprehensive analysis of the studied object and will help to identify the parameters of an overhead power line at the construction stage or for its connection to the consumer. The article presents the experimental setup scheme, describes the experimental methods, and estimates the error of the calculation results.

Copyright of Renewable Energy / Vidnovluvana Energetyka is the property of Institute of Renewable Energy of NAS of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A great attention has been recently paid to development of ultrasound technologies for treatment of blood vessels throughout the world. Authors of the paper have developed a new effective treatment method and ultrasound equipment that allow to carry out destruction of intravascular formations with simultaneous increase in elasticity of a vascular wall together with cardiologists from Belarusian Medical Academy of Postgraduate Education and Republican Scientific and Practical Center “Cardiology”. Advantages of the method are absence of necessity in surgical intervention, low probability of complications, low cost of treatment. The main component of the developed ultrasonic equipment is a tube-type stepped concentrator-waveguide having a spherical tip at a distal end with a single axial hole of 0.5 mm-diameter and three radial holes of 0.3 mmdiameter located at an angle of 120° relative to each other. The main effect for application of the concentratorwaveguide is achieved by ultrasonic vibromechanical action of a spherical tip on intravascular formation with subsequent removal of destruction products by their aspiration from a vascular bed. An additional effect is provided due to cavitation action on vascular formation and vessel walls by flow of fluid supplied via an internal cavity of the stepped concentratorwaveguide through the holes in the spherical tip. This contributes to a significant improvement in elastic properties of a vascular wall in atherosclerosis and diabetes. It is necessary to ensure high accuracy and quality of surfaces for the formed microholes in order to achieve maximum efficiency of the cavitation jet impact on intravascular formations and on the vascular wall. According to the analysis results on specific features of existing methods for small-diameter hole shaping, an electrochemical hole cutting method has been proposed which allows to obtain accurate micro-holes with a diameter of 0.3 mm and high surface quality in parts of small cross section and rigidity. The paper presents results of study on effect of electrochemical holes cutting parameters (voltage, concentration and consumption of electrolyte) on size and shape of the formed microholes. Main modes of electrochemical holes cutting process have been developed which allow to form micro-holes in a spherical tip of a tubular concentrator-waveguide with required accuracy, dimensions and shape.

However, the ECP in its classical form has a number of significant drawbacks. One of them is a dependence of treatment modes and electrolyte compositions on the processed material. In addition, aggressive expensive electrolytes that require special technologies for disposal are used for ECP. Electrolytes in ECP often require heating to a temperature of 60–90 °C. Processing at such temperatures causes significant harm to the environment and production personnel. To eliminate the existing disadvantages of the ECP and expand its technological capabilities, a processing method with application of pulsed unipolar and bipolar modes has been proposed. As a result, fundamentally new processes of pulse ECP with a pulse duration of 0.05–20.00 ms have been developed. They provide a reduction of energy costs for the process and high efficiency of polishing in comparison with traditional DC polishing. The rate of smoothing micro-roughness of the treated surface related to the total metal removal is significantly increased. The use of pulse modes in comparison with traditional ECP allows processing in universal electrolytes of simple compositions based on sulfuric and orthophosphoric acids without addition of chromium anhydride. Application of the developed pulse modes, which will provide at low metal removal a significant change in surface roughness, is the most appropriate for the ECP of precise parts, products or parts of small cross-section and rigidity, such as medical devices for minimally invasive surgery, precision engineering parts, etc. The paper presents results of a study for influence of pulsed unipolar and bipolar ECP modes on the surface quality of stainless steel specimens, as well as a comparative analysis of the efficiency of using pulsed ECP modes instead of DC polishing. The technological parameters of ECP using pulsed modes, providing the highest quality surface polishing with high efficiency of micro-roughness smoothing and low energy consumption have been established in the paper.

Goal. To analyze the options for the development of the 110 kV electricity network with sources of distributed generation. Establishing the relationship between power of the source of distributed generation with the voltage changes in the nodes and transformer active power losses change. To provide the minimum value of network active power loss the authors justify the conditions for optimal connection of the source of distributed generation and value of its power. Methodology. The authors have used the DigSilent Power Factory software environment to create a 110 kV network model and have made a series of simulation of the network operating modes with solar power plants. Results. Based on the operational parameters it is established that the change in power generation in the accepted limits normally does not lead to abnormal voltage variations in the nodes, with power losses having characteristic changes due to alterations in the network of power flows. In the network with solar power plants, the transformer losses of active power is reduced with increasing generation power, except for the most remote nodes from the balancing point, in which losses reduction takes place with load of transformers approximately up to 60 %. At significant overloads of transformers (up to 130 %) there is reactive power losses increasing in comparison with losses in the network without solar power plants. The dependence of active power losses in the network on the load of transformers has a nonlinear character). For each node at one value of transformer load the active losses are different. Less reactive power losses occur at lower load ratios of transformer. When increasing the load of transformers, the rate of increase in reactive losses is higher than the active ones. Also for closed networks with voltage of 110 kV it has been found that the optimal node for connecting the distributed generation is a node with a flow division of power. If there are several such nodes in the network, the optimal one for connecting is the node with the maximum load. The optimal power of the solar station in the node should not exceed 110 % of the installed transformer's power. Originality. For the first time the dependence between the place of the best connection source of the distributed generation with the point of flow distribution with the greatest current fraction from network balancing point was established. In this case the power of the source of distributed generation must not exceed 10 % of the total power of the transformers in this node. Practical significance. We have obtained reasonable conditions for connecting source of distributed generation to a closed electric network of 110 kV without performing large volumes of mode calculations. Namely, the optimal connection point is the point of flow distribution with the greatest current fraction from network balancing point.

Abstract. High-speed railways are fast-growing and promising type of traffic. In Russia development of high-speed railway service is associated with the solution of a number of problems, including infrastructure. Authors propose to use earth connection of the railway catenary with the help of an artificial earthing switch on currently designed high-speed line Moscow—Kazan for 2×25 kV power supply system. Taking into account requirements for electrical safety conditions for maintenance of the track and earthed catenary supports, paper justifies method for calculating allowable voltages of rail—earth points and supports of catenary. Methods takes into account structural features of ballastless track superstructure used for high-speed lines. It is estimated that the voltages admissible under the electrical safety conditions are random in nature and distributed logarithmically normal. When calculating probability of safe operation, one should take into account random nature of both permissible stresses and those actually occurring on the track. It is estimated that the probability of safe operation in traction networks of sections with ballastless track superstructure does not exceed a similar value in electrified sections with the conventional structure of a ballast prism. Feasibility of using a 2×25 kV earth system using an artificial earth connection is confirmed, recommendations on its use are given. Authors substantiate allowable values of the rail—earth voltage and catenary supports, which practically exclude the occurrence of hazardous situations for personnel maintaining the track in sections with ballastless track superstructure.

Titanium and niobium alloys are widely used at present in aircraft, nuclear energy, microwave technology, space and ultrasonic technology, as well as in manufacture of medical products. In most cases production technology of such products involves an implementation of a quality polishing surface. Mechanical and electrochemical methods are conventionally used for polishing products made of titanium and niobium alloys. Disadvantages of mechanical methods are low productivity, susceptibility to introduction of foreign particles, difficulties in processing complex geometric shapes. These materials are hard-to-machine for electrochemical technologies and processes of their polishing require the use of toxic electrolytes. Traditionally, electrochemical polishing of titanium and niobium alloys is carried out in acid electrolytes consisting of toxic hydrofluoric (20–25 %), sulfuric nitric and perchloric acids. The disadvantage of such solutions is their high aggressiveness and harmful effects for production personnel and environment. This paper proposes to use fundamentally new developed modes of electrolytic-plasma treatment for electrolyte-plasma polishing and cleaning products of titanium and niobium alloys while using simple electrolyte composition based on an aqueous ammonium fluoride solution providing a significant increase in surface quality that ensures high reflectivity. Due to the use of aqueous electrolyte the technology has a high ecological safety in comparison with traditional electrochemical polishing. The paper presents results of the study pertaining to the effect of titanium and niobium electrolytic-plasma polishing characteristics using the developed mode for productivity, processing efficiency, surface quality, and structure and properties of the surface to be treated. Based on the obtained results, processes of electrolytic-plasma polishing of a number of products made of titanium alloys BT6 (Grade 5), used in medicine and aircraft construction, have been worked out in the paper.

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electrometallurgy Today / Sovremennaya Elektrometallurgiya is the property of International Association Welding (Paton Publishing House) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Anisotropic space charge limited current density analysis in TlGaTe2 single crystals has been investigated. It is shown that, above 330 K, the crystal exhibits intrinsic and extrinsic type of conductivity along (c-axis) and perpendicular (a-axis) to the crystal's axis, respectively. The current density (J) is found to be space charge limited. It is proportional to the square and three halves power of voltage (V ) along the a- and c-axis, respectively. [ABSTRACT FROM AUTHOR]

Background. The reactivity of cotton pulp during chemical processing is significantly lower compared to celluloses obtained from other cellulose-containing plants. Increasing the reactivity of cotton cellulose to chemical processing improves the quality of the resulting products based on it, as a result, labor productivity increases. Purpose. Replacing wood pulp imported from foreign countries with domestic cotton cellulose by increasing the reactivity of cotton cellulose to chemical processing, improving product quality and increasing the reaction rate. Methodology. In this work, we used methods for determining the composition and structure of cotton cellulose samples. The reactivity of the obtained samples to acetylation after treatment with electric charges was studied. An increase in reactivity was evaluated by a decrease in crystalline areas based on diffractograms that were recorded on a computer-controlled XRD-6100 apparatus (Shimadzu, Japan). Originality. A method is proposed for increasing the reactivity of cotton cellulose by treating it with high-voltage electric charges. Findings. The optimal voltage limits of 11-13 kV, the number of pulses 22-24, the capacitor capacitance of 0.6 µF were found, at which the maximum values of the reactive activity of cotton cellulose were achieved. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Works / Elmi Eserler is the property of Azerbaijan University of Architecture & Construction and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One of the main tasks to be performed when organizing the operation of the energy system is to ensure high-quality and uninterrupted power supply to consumers. Dips, interruptions and voltage surges of the electrical network are the most common causes of malfunctions in industrial plants and damage to household equipment, causing significant economic damage to both consumers and electricity suppliers.

The basic known methods of signal voltage measuring were considered. The circuit solutions used in the construction of digital voltmeters were analyzed. Their advantages and defects were analized. Method of direct assessment of alternating current voltage is proposed to improve by using the developed method for measuring root-mean-square value of alternating current voltage and the device for the realization of the method. It is set, that the use of improved method provides an increase of the inharmonious signal voltage measuring accuracy in conditions of additive noise. Circuit solutions that used for making of digital multimeter using the improved method for measuring of alternating current voltage were described.

The article discusses the disadvantages of digital measuring instruments. Formulated the task of modeling the measuring device for different waveforms and measurements with the use of microcomputers. Studied and selected mathematical models to describe the behavior of measuring instruments and for different waveforms. Modeled amperage characteristics of a simple electrical circuit to check the correctness of the choice and implementation of the models. Implemented a program of virtual simulation for signals of different forms. The program allows measurements regardless of the waveform that is a distinctive feature of the developed program.

Copyright of Electrometallurgy Today / Sovremennaya Elektrometallurgiya is the property of International Association Welding (Paton Publishing House) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Renewable Energy / Vidnovluvana Energetyka is the property of Institute of Renewable Energy of NAS of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Influence of surfacing modes on welding-technological properties of different types of high-alloyed flux-cored strips was studied. Electrode metal melting coefficient, surfacing coefficients, loss factors, as well as the efficiency of electrode material melting and deposition rate, were determined. Widely applied in industry Pl-AN-101 and PL-AN-179 flux-cored strips made using steel strip-sheath, as well as PL-AH-111 strip with nickel sheath were selected as the objects of study. Surfacing of samples for investigations was performed in A-874N machine with AD-167 attachment and VDU-1201 power source in a wide range of modes: current of 600 - 900 A, voltage of 32 - 40 V, speed of 32 - 55 m/h. Obtained results are presented graphically. It is found that alongside the surfacing modes, the filler-powder composition and sheath strip material have a significant effect on the characteristics of welding-technological properties of flux-cored strips and chemical composition and hardness of deposited metal, respectively. At surfacing with PL-AN-111 strip with a nickel sheath, having a high ohmic resistance, more intensive heating of the flux-cored strip in the extension takes place, and, consequently, the coefficient of electrode material melting is increased. Melting efficiency was lower at surfacing with PL-AN-101 and PL-AN-179 strips. At current rise, burning and spattering losses become greater for PL-AN-111 strip, and change only slightly for PL-AN-101 strip, while for PL-AN-179 strip they decrease abruptly in the current range of 900 - 1200 A, because of the specifics of filler-powder composition. Values of melting and surfacing coefficients, as well as melting efficiency and deposition rate decrease with increase of process speed for all the strip types. For PL-AN-111 strip, however, these values change only slightly. [ABSTRACT FROM AUTHOR]

Copyright of Renewable Energy / Vidnovluvana Energetyka is the property of Institute of Renewable Energy of NAS of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The indicators of power consumption of lighting devices based on LEDs are studied depending on the supplied voltage. For the lamp and floodlight with LEDs active and reactive power, current and power factor as a function of voltage (which value changed in the range 200–245 V) were experimentally determined. The analysis of experimental data demonstrated that due to the drivers in the specified voltage range the active power consumed by light devices remains practically unchanged. The reactive power of LED devices depends on the supplied voltage and is capacitive in its nature. In contrast with gas-discharge light sources the LED devices under study do not consume reactive power, but generate it. With the change of the supplied voltage from 200 to 245 V the value of the generated reactive power increases to 60 % for the floodlight and 50 % for the lamp. The LED floodlight has a low coefficient of active power. The current consumed by the floodlight has increased by 22 %, and by the lamp – by 13 %. The formulas for determining the maximum value of the length of the calculated section of single-phase group lines were developed, taking into account specific source data. LED light sources tend to feed by electric power by single-phase group lines. The number of lamps connected to single-phase lines is regulated by normative documents. Bearing this in mind as well as the small power of LED sources single-phase group lines are usually performed with conductors of the smallest possible cross section. The limit values of the length of the calculated section that correspond to a predetermined loss of voltage in line with ambient temperature from 15 to 60 °С were determined for them. The calculations demonstrated that for group lines that feed the LEDs, the choice of conductor cross-sections in accordance with permissible voltage loss is not critical. The determinant factor for the choice of the cross-section of the conductors of group electrical networks is the calculation of acceptable heat with respect to temperature of the environment.

One of the activities of the research center for “Energy Saving Technologies and Smart Metering in Electrical Power Engineering" is research work on the use of electronic devices and systems of intelligent power distribution, produced by Analog Devices and equipped with the accurate energy consumption measurement feature. The article focuses on the development of the analyzer of quantity and quality of electric energy.The main part of the analyzer is a metering IC by Analog Devices ADE7878, designed for use in commercial and industrial smart electricity meters. Such counters measure the amount of consumed or produced electric energy with high accuracy and have the means of remote meter reading.

The article explains the possibility of refusal of application of catenary supports of railway track for grounding and use an artificial grounding conductor for this purpose. The Artificial Grounding Conductor (AGC) consists of two metal strips located in the earth on which surface there are cable lines, metal covers of which are grounded on these strips through 1,2 - 1,5 km, but not closer than 200 m from places of connection of the grounding wires to them. Metal strips on traction substations or at the autotransformer points (AP), and also in the middle between two next AP are connected to a railway track or to the center tap of specially installed track impedance bond between APs. When connecting a cable of group grounding with fittings of catenary support it is possible to refuse AGC grounding to track impedance bond. It is noted that when calculating short-circuit currents between adjacent autotransformers, as well as in determining the input resistance of the electric traction network of 2 × 25 kV with a small inaccuracy it is possible to take into account only these autotransformers and neglecting shunt action of other autotransformers. It is shown that in the place of short-circuit the voltage of the artificial grounding conductor - earth system (railway track - the earth) has a maximum point on each autotransformer section. With distance from the first section from substation the value of this voltage decreases slightly and for the next section differs in 10 - 15 %. In the place of connection of AGC to railway track this voltage decreases approximately up to 30 - 40 %. Efficiency of use of the offered grounding system for sections with the supports disconnected from railway tracks, as well as for grounding of metal barriers of station platforms and metal barriers of railway tracks is established.

This paper considers the problem of thermal shock in the case of a massive body in different conditions of heating and cooling. The most dangerous mode of heating was identified. The influence of inertial effects on the value of emerging thermal stress was investigated. A new equation of compatibility of stress with the inertial effects, which generalizes the known Beltrami-Mitchell relation for quasi-static cases, was obtained by methods of the tensor algebra. The theory of thermal shock in solids was developed in terms of dynamic problems of thermoelasticity in different forms of heat stress: temperature heating; thermal heating; heating medium. Equations for the calculation the jumps in the front of thermoelastic waves were obtained. The most dangerous mode of thermal shock was identified. The effect of relaxation in thermal problems was described in the context of the investigation of thermal stress state of a massive body. It was shown that an increase in relaxation time, i.e. heating rates of the boundary surface of the body, causes a reduction of thermal stress maxima. Original results of the thermal reaction of a solid to cooling were obtained. It was shown that, in comparison with the heating mode, the cooling mode is more devastating, especially for nearsurface layers of solids. The role of the relaxation temperature in the cooling mode was identified. New functional structures were proposed as analytical solutions to the major dynamic problems of thermomechanics on the basis of the use of the Kar functions, which are relatively new.

Purpose.The aim of this study is to obtain a method for determining the capacity surge arrester nonlinear absorb energy without breaking the heat balance in modes of long-term application of operating voltage, which allows for analysis of their work in terms of violations as electricity. Methodology. For values of the energy passing through the arrester must be able to determine the current value for the voltage value in the area of leakage current-voltage characteristics. We have carried out calculations of the energy passing everywhere arrester for certain periods of time based on the current-voltage characteristics obtained experimentally. Analysis of the experimental current-voltage characteristics of resistors and literature led to the important conclusion that the dielectric properties of the ceramic varistor affect the value of active power losses in the arrester only when the active component of the leakage current is very small. This is confirmed by the characteristics of different classes of varistor voltage. This property of varistors and surge arresters shows the need to consider how the dielectric and conductive properties of the varistor ceramics in the analysis of work in the area of the arrester leakage current-voltage characteristic. These results demonstrate the need to clarify the mathematical model and the method for determining the energy dissipates in the area of the arrester leakage current CVC with their account. Results. The study, an improved mathematical model for calculating energy affects surge arrester during its working life. The study obtained the method, of evaluation capacity surge arrester, maintains heat balance throughout working life. Based on experimentally obtained current-voltage characteristic of the varistors is defined voltage at which surge arrester starts conducting active current. This allowed to receive specified mathematical model for calculating energy affects surge arrester and develop a method of evaluation capacity surge arrester maintain heat balance throughout working life.

Nowadays the work is in progress to develop wheeled and caterpillar tractors with electromechanical transmission. Range of changes in transmission gear ratio while using propulsion electric motor depends on mechanical characteristics of a tractor propulsion electric motor which is equipped with electromechanical transmission. In case when the range is rather high then it is possible to minimize number of gearings in the tractor gearing box or exclude its usage at all. Type of the applied propulsion electric motor and regulation method specify type of mechanical characteristics (characteristics family) of the propulsion electric motor.The paper considers a propulsion asynchronous electric motor with frequency control. While using frequency control it is possible to regulate electric motor revolutions by mutual changes in voltage and voltage frequency. There are various laws of mutual changes in voltage and frequency (regulation laws). Selection of a regulation law influences on type of mechanical characteristics of a propulsion electric motor. Application of any law can be admissible only for some specific range of voltage frequency otherwise it is possible to exceed some parameters (for example, admissible voltage in the winding of electric motor stator). It is necessary to ensure the required moment within wide range for a tractor propulsion electric motor. In this case losses in the electric motor must be minimal. Losses in the rotor of the propulsion asynchronous electric motor are directly proportional to its sliding and its best propulsion and mechanical properties of a mobile machine will be ensured in the case when sliding is preserved at a constant value. According to these reasons selection of regulation laws has been carried out for operation of the propulsion asynchronous electric motor with nominal sliding and mechanical characteristics at nominal sliding is conventionally called a nominal characteristics.The paper analyzes the possible laws of mutual application of voltage and voltage frequency and their application boundaries. A combination of laws for regulation of the propulsion asynchronous electric motor has been selected in the paper. The combination ensures the widest operational range of the electric motor with high moment value at nominal sliding and due account of limitations on application of every used regulation law. The following mechanical characteristics family has been constructed for the propulsion asynchronous electric motor regulated in accordance with the proposed law: at nominal sliding, at critical sliding, at changeable sliding and without changes in voltage and frequency.

The paper proposes the non-canonical spectral decomposition of random functions of the traction voltages and currents. This decomposition is adapted for the electric transportation systems. The numerical representation is carried out for the random function of voltage on the pantograph of electric locomotives VL8 and DE1.

The paper tackles the substantiation aspect of the AC traction power supply system (TPSS) allowing reduction to the permissible level in the voltage symmetry coefficient on the input side of the main traction transformer of the AC traction substation. For this purpose it is recommended to insert multifunctional booster transformer in the TPSS. Its input power (main) winding is connected to one of the 27.5 kV-side branches of the main traction transformer, booster winding is brought in the traction substation feeder line and compensating winding is loaded on the adjustable capacitor unit. Data products of analytical calculations, performed by the proposed by the authors analysis procedure of electromagnetic processes in the TPSS with the multifunctional booster transformer, allowed to substantiate the capacitor unit parameters for the case of its energizing to carry the compensating winding’s 2.5 kV. When performing calculations the account was taken of the possible electric locomotive casting in the form of a power source and of a current source as well. While analyzing current distribution within the TPSS with multifunctional boosting transformer the authors used the standard set of equations, formulated by the mesh technique. In the case of current collector conceiving as a power source the necessity of employing iteration procedure was caused by non-linearity of the system under consideration due to quadratic dependence of electric locomotive resistance on the current collector voltage. Similar procedure was also employed in the case of current collector conceiving as a current source. For the case of employing adjustable capacitor unit it was found that according to the law presented in the paper, asymmetry coefficient does not exceed the values set by the GOST 13109-97 while leading and retarding phases’ currents differ from each other in modulus by no more than 30 %. It is noted that with booster winding of the multifunctional booster transformer brought in the traction substation feeder line it becomes possible to increase the retarding phase voltage by the value very near to the EMF induced in the booster winding due to its magnetic interaction with the input power winding and to raise simultaneously the leading phase current by somewhat lower value.

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)