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Date submitted2021-04-27
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Date accepted2021-11-30
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Date published2021-12-27
Regularities of electrochemical cleaning of oil-contaminated soils
Electrochemical cleaning of oil-contaminated soils is a promising area of environmental safety, as it can be easily organized even in locations remote from settlements. For this purpose, a power source and a system of electrodes are necessary as equipment. It is possible to use an electric generator if there are no power supply lines nearby. The material of electrodes affects the features of redox processes, which can affect the energy consumption and the degree of soil cleansing from oil or oil products. Therefore, the correct choice of electrode materials is one of the important tasks in the field of engineering electrochemical methods of purification. Changes in the main parameters (humidity, temperature, degree of acidity) in an oil-contaminated model soil, similar in composition to one of the oil fields, were investigated. Measurements of parameters when using graphite and metal electrodes were carried out at several fixed sections of the interelectrode space depending on the treatment time. The established patterns of parameter changes in the purification of oil-contaminated soils allow us to draw conclusions about the stages of the electrochemical process, its speed, and energy efficiency. The results obtained form a basis for designing industrial facilities for soil treatment.
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Date submitted2020-10-05
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Date accepted2021-03-30
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Date published2021-06-24
Improving the efficiency of relay protection at a mining and processing plant
The paper presents the results of constructing effective relay protection in the power supply system of a mining and processing plant (MPP). A brief description of the MPP is given, the power supply and substitution circuits used to calculate the short-circuit currents are given. A statistical analysis of failures in the electric network of the MPP has been carried out, which makes it possible to draw conclusions about the nature of failures ranges. Analysis of the registered faults shows that a significant part of them are line-to-earth faults, which in most cases turn into multiphase short circuits, which are interrupted by overcurrent protection. In order to improve the efficiency and reliability of the relay protection, the power supply scheme of the MPP was refined and analyzed. The calculation of the short-circuit currents was made, which made it possible to calculate the settings of the relay protection and give recommendations on the place of its installation and adjustment in order to ensure the normal operation of electricity consumers. To reduce the number of failures to the cable insert on the line leaving the administrative and household complex (AHC), and to increase the reliability of power supply to consumers, it is advisable to divide the capacities of the existing 10 kV line into two parallel ones by laying a second line. It is recommended to install a current cut-off on the line outgoing to the AHC, the feasibility of the installation of which was shown by calculations. This will reduce the chance of failures to the cable gland. Data on the setting currents of overcurrent protection and current cut-off are given on the selectivity card.
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Date submitted2020-05-16
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Date accepted2021-03-02
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Date published2021-04-26
Study of drive currents for lifting bridge cranes of metallurgical enterprises for early diagnosis of load excess weight
The article discusses an approach based on the analysis of the drive motor currents to create an additional means of protection against emergency situations during the operation of bridge cranes associated with lifting a load with a mass exceeding the permissible one . A mathematical model of an overhead crane drive is described, as well as the results of computer simulation. It is shown that in the process of lifting up, before the stage of lifting the load, the stator current of the drive electric motor does not depend of the load mass, but when the load is detached, already for several periods of the mains voltage after the rope is pulled, when the mass of the load is exceeded, a measurable excess of the amplitude value of the current is recorded. This pattern has been confirmed for a number of cranes of various lifting capacities used at metallurgical enterprises. The possibility of diagnosing excess weight of the lifted load with a higher speed than existing mechanical methods of overload control is demonstrated, at the same time it is not required to make changes to the structural elements of overhead cranes.
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Date submitted2019-03-31
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Date accepted2019-08-25
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Date published2020-02-25
Cascade frequency converters control features
The structures of systems with high-voltage cascade frequency converters containing multi-winding transformers and low-voltage low-power converters connected in series at each output phase of the load are considered. Low-voltage blocks contain three-phase diode or active rectifiers, DC capacitor filters, single-phase stand-alone voltage inverters and block disconnecting devices in partial modes (in case of failure when part of the blocks are disconnected). The possibilities of operation of cascade converters are determined, equations for correcting tasks to units in partial modes are given, tables of correction of tasks with estimates of achievable load characteristics are proposed. The results of experiments on the model of a powerful installation with a cascade frequency converter are presented, confirming the possibility of ensuring the symmetry of the load currents when disconnecting part of the blocks and the asymmetry of the circuit.
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Date submitted2016-11-14
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Date accepted2017-01-09
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Date published2017-04-14
Method of restoring strength determination test
- Authors:
- S. M. Apollonskii
- Yu. V. Kuklev
The main requirements for an electric unit at the stages of its design, development, production and usage are described in technical specifications (TS) and standards (GOST). The electric unit should work in accordance with a specific purpose and have significant reliability, durability and safety. The reliability and durability of electric unit significantly depends on restoring strength speed value, that is growth of breakage voltage in arc pass for eliminating repeated arc strike. This article describes several methods of test identification of restoring strength, which were carried out at special testing laboratory units. They are described in relation to conditions of measuring the residual arc column of AC current after it reaches zero point and can be used in designing arc blowout units of low voltage.
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Date submitted2015-12-29
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Date accepted2016-02-21
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Date published2016-12-23
Poorly studied phenomena in geoelectrics
- Authors:
- V. S. Mogilatov
Undoubtedly, modern geoelectric technologies emerge in the result of the development of traditional approaches and techniques. However of more interest is the appearance of completely new technologies based on new effects and new models of interaction of geological medium and electromagnetic field. The author does not commit to indicate principally new directions, but only wants to discuss some poorly known facts from the theory and practice of geoelectrics. The outcome of this study could be considered attracting the attention of experts to non-traditional signals in geoelectrics. The reviewed phenomena of interest, not fully implemented in practice in the author’s opinion, are field split into two polarizations: transverse electric (the ТЕ-field) and transverse magnetic (the ТМ-field), then some poorly known properties of ТМ-field, the role of bias currents, the anisotropy of horizontal resistances, the role of geomagnetic field in geoelectric sounding, the unique resolution of CSEM (Controlled Source Electro-Magnetic) techniques at sea.
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Date submitted2009-09-22
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Date accepted2009-11-23
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Date published2010-06-25
Scientific-technical progress and innovation development in sociological science history
- Authors:
- V. N. Zavrazhin
The paper is dedicated to the consideration of interrelation of scientific-technical progress and social progress as one of the most important subjects of sociological science. Some classical and modern macrosociological theories are in the centre of attention, that develop progressive approach in understanding the place and role of scientific-technical progress and innovation development in the life of society. The emphasis is made on the actualization of macrosociological analysis of the problems stated in the paper in the current global economic crisis context.
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Date submitted2009-08-25
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Date accepted2009-10-25
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Date published2010-02-01
The phenomenon of spontaneous termination of the discharge current and the establishment of fully-managed key elements of the plasma
For the first time magnetic and probe technique for diagnostics of anisotropic plasma have been worked out. Contemporary digital measuring methods, plasma plants and new generation devices of plasma energetics as well as special mathematical programs for fundamental investigations of anisotropic plasma were created. The inventions of Saint Petersburg Mining Institute are used for solving of plasma energetic problems.