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.

Determination of the dynamic characteristics of freight wagons with various bogie

Abstract: In most cases, dynamic characteristics determine the wagon maintenance cycle, traffic safety, reliability and durability performance. The main dynamic indicators include the vertical Kvd and horizontal Khd dynamic coefficients as well as the stability coefficient Ks, which determines the wheel flange resistance to derailment. The article compares dynamic indications for three different types of bogies. There were no tangible differences observed for all the three different types of bogies running at a speed of 40 to 120 km/h on a direct tangent rail section. Nevertheless, there is a realistic potential to improve the dynamic indicators of a freight wagon by rationalising suspension unit parameters.

Improving hardness and tribological characteristics of nanocrystalline Cr–C films obtained from Cr(III) plating bath using pulsed electrodeposition

Abstract: Effect of pulsed electrodepostion on the nanocrystal size, composition, hardness, coefficient of friction and wear resistance was investigated for the Cr–C electrodeposits obtained from a trivalent chromium bath. The electrodeposits were shown to contain about 9% of carbon. Pulsed electrodeposition does not virtually affect the carbon content. At the same time, an increase in the off time duration leads to a decrease in the nanocrystals size. The hardness and wear parameters of the electrodeposits may be sufficiently improved when using pulsed current. For instance, at ton = toff = 1 s, the hardness reaches the values of ~ 1200 ÷ 1300 HV (meanwhile, it is close to 850 ÷ 950 HV at a steady-state electrolysis).

Modelling of the Return Traction Current Harmonics Distribution in Rails for AC Electric Railway System

Abstract: The problem of determination of the traction current harmonics distribution in rails generated by several trains that operated in AC feeder zone is considered. The investigations were caused by necessity to ensure electromagnetic compatibility of the new types of rolling stock equipped with electronic static converters with track circuits that are used in train movement control systems for detection of their positions. The great diversity of rolling stock, power supply and return current systems, and train detection systems installed in European countries leads to consideration of the electromagnetic compatibility problem taking into account the specific railway systems used in the each country. Investigation of the electromagnetic compatibility between different railway subsystems requires the use of simulation programs that help to reveal most critical conditions for electromagnetic compatibility at an early stage and also makes it possible to estimate electromagnetic interference from rolling stock in rails under the worst-case conditions, realization of which in the operating systems will require a lot of time and cost. This work consider evolved model for distribution of the traction current harmonics in rails from several trains. To illustrate the application of the considered model, the distribution of the traction current harmonics in rails was computed for25 kV AC direct feeding network depending on distance from electrical supply substation, the rail-to-earth conductance, and the number of trains in the feeder zone. The results of modeling of the harmonics distribution are in satisfactory agreement with the experimental data.

Philosophical and psychological dimensions of social expectations of personality

Abstract: Purpose. To analyse the philosophical and psychological contexts of social expectations of personality, to form general scientific provisions, to reveal the properties, patterns of formation, development and functioning of social expectations as a process, result of reflection and construction of social reality. Theoretical basis of the study is based on the phenomenology of E. Husserl, the social constructivism philosophy of L. S. Vygotskiy, P. Berger, T. Luckmann, K. J. Gergen, ideas of constructive alternativeism of G. Kelly, psychology of social expectations of a personality as the unity of the mental process, mental state and properties of expectations. Originality. Social expectations of personality are considered as philosophical and psychological dimensions of the study, presented by analysing expectations in social constructivism, externalizing, building a model of the expected future. The authors clarified some theoretical and methodological aspects of the study of patterns of social expectations in the reflection and construction of social reality. The role of social institutions in the formation of expectations is outlined. The poly-aspect of the investigated problems is shown. It is substantiated that formation, realization of social expectations in organization of interaction of personality and social environment is possible in the presence of subject, object and content of activity. Conclusions. Social expectations influence social behaviour and determine the behaviour of an individual, small contact group, community, or large mass of people. Social expectations are able to set specific requirements, norms, sanctions, ideals that participants of the process must follow or must not violate. The philosophical dimension of the study integrates the ontological, epistemological, axiological preconditions for the formation and realization of the social ideal, represented by the study of the expected future in the forms of utopia, eschatology and thanatology. Psychological dimension of the study has a sufficiently developed content orientation from the psychological content parameters of social expectations to the role of expectations in social institutions and various spheres of human life. Systematic, actionable, self-regulatory, and subjective approaches have constituted a verified system of interpreting the social expectations of personality as a process, a result of the reflection and construction of social reality. The topic of social expectations of personality is far from being completed, in our opinion it is promising to create a deeper philosophical concept of social expectations of the personality. The specific topics are of particular relevance in the context of socio-political uncertainty, domination of the mass consciousness, loss of national and cultural identity.

Probabilistic approach for the determination of cuts permissible braking modes on the gravity humps

Abstract: Summary. The paper presents the research results of cuts braking modes on the gravity humps. The objective of this paper is developing the methods for assessment of braking modes of cuts under conditions of fuzziness of their rolling properties, as well as selecting the permissible starting speed range of cuts from retardant positions. As a criterion for assessing the modes of target control of cut rolling speed, it was proposed to use an average gap size on a classification track at the established norms of probable exceeding of permissible speed of cars collision and their stop in retarders. As a criterion for evaluating the modes of interval control of cuts rolling speed, using the risk of their nonseparation on the switches was proposed. Using the simulation modeling and mathematical statistics, the configuration of the range of permissible speed of cuts coming out from retardant positions has been set. The conducted researches allow simplifying the choice of cut braking modes in systems of automatic control of cut rolling speed. ВЕРОЯТНОСТНЫЙ ПОДХОД К ОПРЕДЕЛЕНИЮ ДОПУСТИМЫХ РЕЖИМОВ ТОРМОЖЕНИЯ ОТЦЕПОВ НА СОРТИРОВОЧНЫХ ГОРКАХ Аннотация. В статье представлены результаты исследований режимов торможения отцепов на сортировочных горках. Целью статьи является разработка методов оценки режимов торможения отцепов в условиях неопределенности их ходовых характеристик, а также поиск области допустимых скоростей выхода отцепов из тормозных позиций. В качестве критерия для оценки режимов прицельного регулирования скорости скатывания отцепов предложено использовать среднюю величину окна на сортировочном пути при установленных нормах вероятности превышения допустимых скоростей соударения вагонов и остановки их в замедлителях. В качестве критерия для оценки режимов интервального регулирования скорости скатывания отцепов предложено использовать риск их неразделения на стрелках. С помощью методов имитационного моделирования и математической статистики установлена конфигурация области допустимых споростей выхода отцепов из тормозных позиций. Выполненные исследования позволяют упростить решение задачи выбора режимов торможения отцепов в системах автоматического управления скоростью их скатывания.