Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan

About: Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan is a education organization based out in Dnipro, Ukraine. It is known for research contribution in the topics: Track (rail transport) & Bogie. The organization has 736 authors who have published 655 publications receiving 1468 citations. The organization is also known as: Institute of Railway Transport Engineers.

Improvement of Technical Service of Track Circuits

Abstract: The automated method of measuring the time and amplitude parameters of code current and parameters of track circuits (input impedance of the track circuit, a characteristic impedance, a propagation constant) were elaborated. The mathematic model of track circuits' channel of transferring code current was improved and considered in this paper. The algorithms of definition of parameters of track circuit are offered.

The accuracy of traction current harmonics parameters determination by windowed FFT

Abstract: In the work the correct choosing of the windowed FFT parameters to achieve the necessary time and frequency resolution of the traction current spectral analysis in accordance with the requirements of regulatory documents has been briefly overviewed and investigations of the influence of FFT parameters on the accuracy of the determination of harmonics parameters (such as effective current, frequency, duration) have been carried out. To assess the accuracy of determining the RMS current and frequency of the harmonics, a computer study was performed using a synthesized current with known harmonics parameters, the values of which were chosen in accordance with the permissible values of the parameters determined by regulatory documents and standards. For the spectral analysis of traction current, four types of windows were selected: rectangular, Hann, Hamming and Blackman windows with duration of 0.3 and 1 s. For a sampling frequency of 27500 Hz and a window length of 0.3 s, the frequency resolution is 0.27 Hz for a rectangular window, 0.54 Hz for Hann and Hamming windows and 0.81 Hz for Blackman's window, which is consistent with the requirements of the specifications. The results of spectral analysis of traction current showed that the frequency resolution of harmonics, and accordingly the relative error in determine the frequency and the RMS value of harmonics is lower for high frequencies in spectrum. The type of windows used has a slight effect on the accuracy of determining the frequency of harmonics. The relative error of the effective value of the harmonic current was higher for a rectangular window, and relative error decreased in the row from the rectangular window to the Blackman window. The values of the relative error of the RMS current for several frequencies of the harmonics did not meet the requirements necessary for the practical use of the method, and this is due to spectrum leakage and scalloping. For windows with a length of 1 s, the frequency resolution of the traction current was higher. than for windows with a length of 0.3 s, and the relative error of the RMS current and frequencies of the harmonics were much lower, but even in this case, the relative error was high for individual frequencies . To ensure the necessary accuracy of the traction current spectral analysis with using windowed FFT, proper choosing of the spectral analysis parameters taking into account the traction current parameters is necessary. Taking into account a wide frequency range of traction current, a technique with variable window length and sampling frequency for different parts of the spectrum is perspective for using.

Contradiction between technocratic and humanistic systems of values

Abstract: Purpose . The purpose of the paper is determination of difference between technocratic and humanistic value systems. The authors also suggest to outline the range of issues specific to modern technological civilization, reflect its controdictory nature, as well as to focus on the university activity fields concerning formation and/or restoration of technocratic and humanitarian balance. Method ology . The most important methodological principle of the work is a systematic approach. It has determined logic of description and conclusion. During the study authors analyzed separate aspects of social development of the late 20th – early 21st centuries, as well as content analysis of the global information flow (documentary and non-documentary) on this topic and their own observations, obtained during the implementation of long-term educational and scientific practices at the university. It is, for example, drawing up a comparative table of technocratic and humanistic value systems. The authors have conducted a comparative analysis of 2 Sociological Research data (2009 and 2013 years) among university youth of Dnipropetrovsk "Modern Library by Students′ Eyes" and trending concerning the issues about the role of reading in the students lives. Findings . The difference between the technocratic and humanistic value systems was determined. Contemporary problems of the personal intellectual development in the process of education and training in technical universities during the dominance of technocratic value systems were outlined. Attention is focused on the university directions on formation and / or restoration of technocratic and humanitarian balance. Originality . The authors have analyzed and outlined a range of issues specific to contemporary industrial civilization, its controversial nature was reflected. Rebalancing of the technocratic and humanitarian is one of the major tasks in our time. The directions of universities activities were determined. P ractical value . Highlighting the several problems solving necessity will ensure harmony in the interaction of technocratic and humanistic value systems. The material presented in this article can be used in the teaching of Humanities and Social Sciences, in the activities of various cultural and informational, mass-cultural, social structures of the University; the activity directions of which suggest a sociocultural understanding of technology, its achievements, the consequences of its development, the responsibility for its use, contributing to the restoration of harmony in the development of human and technological spheres.

Accumulated deformation modeling of permanent way based on entropy system

Abstract: Purpose . The work provides a theoretical research about the possibility of using methods that determine the lifetime of a railway track not only in terms of total stresses, and accounting its structure and dynamic characteristics. The aim of these studies is creation the model of deformations accumulation for assessment of service life of a railway track taking into account these features. Methodology . To simulate a gradual change state during the operation (accumulation of deformations) the railway track is presented as a system that consists of many particles of different materials collected in a coherent design. It is appropriate to speak not about the appearance of deformations of a certain size in a certain section of the track, and the probability of such event on the site. If to operate the probability of occurrence of deviations, comfortable state of the system is characterized by the number of breaks of the conditional internal connections. The same state of the system may correspond to different combinations of breaks. The more breaks, the more the number of options changes in the structure of the system appropriate to its current state. Such a process can be represented as a gradual transition from an ordered state to a chaotic one. To describe the characteristics of the system used the numerical value of the entropy. Findings . Its entropy is constantly increasing at system aging. The growth of entropy is expressed by changes in the internal energy of the system, which can be determined using mechanical work forces, which leads to deformation. This gives the opportunity to show quantitative indication of breaking the bonds in the system as a consequence of performing mechanical work. According to the results of theoretical research methods for estimation of the timing of life cycles of railway operation considering such factors as the structure of the flow of trains, construction of the permanent way, the movement of trains at high speeds was developed. Originality . For the first time to simulate the accumulation of deformations of railway tracks this figure as the entropy of the system was used. Practical value. Analytic dependences have been brought to practical techniques that make it possible to analyze the track sections with different designs or with different operating conditions in terms of deformation accumulation.

Influence of chemical compounds on the forming of welding arc

Abstract: Purpose. The purpose of work is a comparative analysis of chemical compounds influence on the process of forming arc welding and condition of its burning. Methodology. A wire with diameter 3 mm of low carbon steel with contain of carbon 0.15% was material for electrode. As chemical compounds, which determine the terms of arc welding forming the following compounds were used: kaolin; with admixtures of gypsum up to 60%; and with the iron concentration up to 50%. Researches were conducted using the direct electric current and arc of reverse polarity. As a source of electric current a welding transformer of type PSO-500n was used. On the special stand initial gap between the electrode and metal plate was 1-1.5 mm. The inter electrode space was filled with the probed chemical compound and the electric arc was formed. At the moment of arc forming the values of electric current and arc voltage were determined. After the natural break of electric arc, the final gap value between electrodes was accepted as a maximal value of arc length. Findings. Experimentally the transfer of metal in interelectrode space corresponded to the tiny drop mechanism. According to external signs the relation between maximal arc length and the power of electric current has the form of exponential dependence. Specific power of electric arc at the moment of arc forming per unit of its length characterizes the environment in the interelectrode space. Originality. 1) Based on the analysis of influence of the studied chemical compounds on the formation processes of electric arc the inversely proportional relationship between the power of the electric current and the maximum arc length until the moment of its natural break is defined. 2) Ratio between the maximal arc length and the power of electric current, with the sufficiently high coefficient of correlation is submitted to the exponential dependence. Influence of the compounds under study on the process of electric arc forming is determined using the indexes of degree of the above mentioned correlation. 3) The value of specific power of electric current at the moment of electric arc forming per unit of arc length can be accepted as the parameter, which characterizes the state of interelectrode space environment. Practical value. In the conditions of identical adjusting force of electric current the sequence of location of the studied compounds in the order of increase of their influence on the process of arcing is determined. Minimum influence is observed from kaolin, and maximal one – from .