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Copyright of Chemistry, Physics & Technology of Surface / Khimiya, Fizyka ta Tekhnologiya Poverhni is the property of National Academy of Sciences of Ukraine, Chuiko Institute of Surface Chemistry 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 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. References 15, table 1, figures 3. [ABSTRACT FROM AUTHOR]

The purpose of the paper is presentation of the results of the experimental verification of the method of automatic control of magnetic separator efficiency by magnetic product developed at the National Mining University. The developed method is based on the fact that the electromotive force in electric coil located on the pole piece of magnetic system of the separator is dependent on its efficiency by magnetic product. Functional diagram of the method of measuring the magnetic separator efficiency by magnetic product is given. Theoretical formulas that describe the formation of a pulsating magnetic field in the working area of the magnetic separator and the dependence of the magnetic induction of this field on physical variables that characterize the operating running regime of wet drum magnetic separator are presented. Theoretical dependence of the magnetic induction of the magnetic field in the working area on the amount of magnetite concentrate in a layer on the surface of the separator drum is established. Procedure and the functional diagram of experimental studies of proposed automatic control method at iron ore-dressing plant are given. The procedure involves performing a passive experiment, including sampling and probe analysis with simultaneous reading of the voltmeter which measures the output voltage of the electric coil located on the pole piece of the magnetic system of the separator. Mathematical processing of results of experimental studies was carried out by regression analysis. Regression equation that relates the magnitude of the electromotive force in a coil and a magnetic separator performance by magnetic product is given. Conclusion is drawn that estimation of magnetic separator efficiency by magnetic product is adequately accurate. Obtained results allow developing a system of automatic control of magnetic separators efficiency. [ABSTRACT FROM AUTHOR]

In this paper, we studied the influence of the microplasma structure, operating voltage and temperature on the ultraviolet component of the spectrum distribution of quantum output of SiC-6H and SiC-15R based light emitting diodes, working in the electrical breakdown regime. Moreover, revealed was the well-formed connection of samples parameters with the initial crystallites properties and microplasma structure of the breakdown. The obtained results proved the probability of the range extension of the devices' stable work in the ultraviolet region to 250nm. [ABSTRACT FROM AUTHOR]

This paper illustrates that the dc voltage on the output of the magnetoresistive measurement converter is proportional to active power in a transmission line. Furthermore, we study the inversion switchboards models of current and voltage based on triacs. [ABSTRACT FROM AUTHOR]

This paper develops the sample AC-converters for 0-30MHz frequency range and 0,001-1000 V voltage range with minimized errors from DC to AC voltage. [ABSTRACT FROM AUTHOR]

The paper deals with the development of manufacturing methods of improving the functionality and reliability of the electric contact made of titanic VT3-1 alloy. This alloy is used in the development of electrical contacts for acoustic beacons used on airplanes of various airline companies. Solving the problem of increasing the life of acoustic beacons (up to 90 days) is directly related to an increase in the stability of the electrochemical characteristics of the contact. To ensure the stable behavior of the electric potential (not more than 0.5V) at the contact, a method of gas-dynamic spraying of a protective coating based on nickel of increased thickness is proposed. Single-layer and two-layer coatings obtained from different grades of powder mixtures were tested. The regularities of the process of electrochemical breakdown and passivation of protective coatings during comparative short-term tests were studied. Based on the test results, a single-layer gas-dynamic coating of the composition(Ni + Al2O3) formed from the powder mixture of grade N3-00-02 was chosen. The microstructure, phase composition, microhardness, porosity and adhesive strength of Ni-based protective coating were investigated. Electrochemical tests of electrical contact with the investigated coating in the sea water environment depending on the time factor were carried out. Increased thickness of the coatings combined with low open porosity and high adhesive strength provided stable behavior of the electric potential in the process of applying it to the working surface of the titanium alloy contacts VT3-1. This ensures reliable electrochemical protection of contacts in the sea water environment for 90 days.

Purpose. To determine the contribution of the real contact spots distribution in the total conductivity of the conductors contact. Methodology. The electrical contact resistance research was carried out on models. The experimental part of this work was done on paper with a graphite layer with membranes (the first type) and conductive liquids with discrete partitions (the second type). Findings. It is shown that the contact electrical resistance is mainly determined by the real area of metal contact. The experimental dependence of the electrical resistance of the second type model on the distance between the electrodes and the potential distribution along the sample surface for the first type model were obtained. The theoretical model based on the principle of electric field superposition was considered. The dependences obtained experimentally and calculated by using the theoretical model are in good agreement. Originality. The regularity of the electrical contact resistance formation on a large number of membranes was researched for the first time. A new model of discrete electrical contact based on the liquid as the conducting environment with nuclear membrane partitions was developed. The conclusions of the additivity of contact and bulk electrical resistance were done. Practical value. Based on these researches, a new experimental method of kinetic macroidentation that as a parameter of the metal surface layer deformation uses the real contact area was developed. This method allows to determine the value of average contact stresses, yield point, change of the stress on the depth of deformation depending on the surface treatment.

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.)