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.

The assessment models of air pollution during transportation of bulk cargo

Abstract: Purpose. The scientific work is concentrated on development of 3D, 2D numerical models for the prediction of atmospheric pollution during transport of bulk cargo in the railway car. Methodology. To solve this problem numerical models were developed, based on the use of the motion equations of inviscid incompressible fluid and mass transfer, to determine the field of wind velocity near the cars and dispersion of dust in the atmosphere. For the numerical integration of the pollutant transport equation implicit alternating-triangular difference scheme was used. When constructing a difference scheme splitting of the transport equation is carried out that allows us to construct an efficient algorithm for solving a differential problem. Unknown value of the pollutant concentration at every step of splitting is determined by the explicit scheme – the method of point-to-point computation, which provides a simple numerical implementation of splitting equations. For numerical integration of the 3D equation for the velocity potential method of Richardson is applied. For numerical integration of the 2D equation for the velocity potential the method of total approximation is applied. The developed numerical models are the basis of established software package. On the basis of the constructed numerical models a computational experiment to assess the level of air pollution when demolition of coal dust from the gondola car was carried out. Findings. 3D, 2D numerical models that belong to the class «diagnostic models» were developed. These models take into account the main physical factors affecting the process of dust pollution dispersion in the atmosphere during transportation of bulk cargo, but require small costs of the computer time in the practice at the low and medium power machines. These models are used for serial calculations of various situations of scenarios related to issues of environmental protection and pollution intensity diagnostics for different weather conditions. Computational calculations to determine pollutant concentrations and formation of pollution zone near the cars with bulk cargo in «microscale» scale were submitted. Originality. 3D, 2D numerical models were created. They allow taking into account the relevant factors, influencing the process of pollutants dispersion in the atmosphere, and formation of the pollution zone during transport of bulk cargo by rail. Practical value. Efficient numerical models «diagnostic models» for rapid calculation of the atmosphere pollution level during transportation of bulk cargo by rail were considered. Models can be used in the development of environmental protection measures at the operation of rail transport. Proposed model allows calculating 3D, 2D hydrodynamics of wind flow and mass transfer process of pollutants in the atmosphere.

State and problems of development of insurance market of ukraine

Abstract: Мета. Страховий ринок України дотепер є цікавим для закордонних інвесторів. Однак існує ряд негативних факторів. Це: 1) відсутність досконалої нормативно-правової бази, доступності та прозорості страхового ринку для населення; 2) низька прибутковість окремих видів страхування; 3) нижча конкурентоздатність страхових компаній, ніж комерційних банків у боротьбі за залучення вільних коштів юридичних і фізичних осіб; 4) недостатній рівень державного регулювання та контролю не дають змоги страховому ринку ефективно розвиватись. Тому метою статті є проведення аналізу, виявлення причин, що гальмують розвиток страхової діяльності в Україні, а також визначення напрямків розвитку страхового ринку. Методика. Для досягнення поставленої мети в статті було визначено загальну кількість страхових компаній, складено рейтинг за валовими платежами найбільш крупних із них, представлено динаміку чистих страхових виплат за основними видами страхування. Даний аналіз дозволяє окреслити проблемні питання та напрямки діяльності страхового ринку. Результати. На основі проведеного в статті аналізу виявлено ряд гальмівних факторів у розвитку страхування в Україні та першочергові напрямки поліпшення ситуації, що склалася на страховому ринку. Встановлено, що головними задачами розвитку страхування залишаються: 1) реформування законодавчої бази; 2) підвищення конкурентоспроможності, рівня інвестиційної привабливості страхових компаній; 3) розвиток сучасної інфраструктури страхового ринку; 4) розширення спектру послуг та доведення їх рівня до міжнародних стандартів; 5) підвищення кваліфікації кадрів; 6) удосконалення ліцензування страхової діяльності; 7) підвищення культури та рівня довіри населення. При цьому підвищення рівня платоспроможності населення, стабілізація економіко-політичної ситуації в країні сприятимуть стабілізації та інтенсивному розвитку ринку страхових послуг. Наукова новизна. В статті вперше розроблено науковий підхід щодо визначення системи факторів, яким мусить відповідати сучасний ринок страхових послуг. Практична значимість. Вирішення представлених проблем шляхом запропонованих авторами заходів дозволить успішно розвиватись страховому ринку, який, в свою чергу, сприятиме стабілізації національної економіки, оскільки є невід’ємним її сегментом.

Investigation of the Physical and Mechanical Parameters Interconnection of Pantograph Contact Elements

Abstract: The aim of the work is to establish the relationship between hardness and volume resistivity of the current collectors contact elements of electric rolling stock. Was conducted statistical analysis of the data result of numerous experimental research obtained of the physical and mechanical parameters of carbon contact elements. The theoretical and empirical methods of research used in this work. As a result of the conducted research was found statistical interconnection between contact elements hardness and volume resistivity described by the analytical expression. Taking into account the design features of the contact elements and the requirements for their operation, were established more accurate correlations of the measured values. Using the results obtained in the work will increase the operational reliability of the sliding high-current contact of electric transport.

Накопичення втомних пошкоджень деталей вагонів згідно з критерієм питомої енергії повної деформації

Abstract: Purpose. Modern ideas about the accumulation of fatigue damages in the details of railway vehicles are based on models that estimate the durability of metal systems and depend on the number of cycles and the magnitude of deformations or stresses. These models allow one to assess with a sufficient degree of adequacy the weakening of metal systems in polycyclic fatigue and at the presence of the elastic strain only in the details of rolling stock. However, the possibility of plastic deformation appearing during operation of rail transport structures is not taken into account. The aim of this work is a construction of a mathematical model that allows estimating the durability of metal systems with regard to the appearing of the plastic component in the process of deformation of parts of railway vehicles. Methodology. With the use of modern methods of solid mechanics the influence of the parameters of plastic deformation on the durability of highly loaded structural elements was analyzed. Findings. The effect of elastic and plastic deformation on the energy dissipation under cyclic loading was studied. Originality. It was shown analytically that the softening parameters of metal systems are related to the total energy of deformation, which characterizes features of the degradation processes in the metal structures under external loads. Practical value. Ratios were proposed, they allow estimating residual life of details in a sequential multilevel cyclic loading.

Theoretical and experimental evaluation of strength indices for traction reduction-gear housings of welded construction KEVRZ for electric trains ER2, ER9

Abstract: Purpose. To check meeting the requirements of Standards for experimental specimens of traction gear boxes for electric trains of series ER2, ER9 with housings of welded construction by Kiev Electric Wagon Repair Works (KEVRZ). Methodology. To reach the objective in hand, performing the work, some computational models for theoretical determination of the stress levels in the reduction-gear housing of welded construction by simulating the loading conditions that can take place during the operation have been developed and the stresses at different points of the reduction-gear housing as well as the levels of vertical accelerations of the reduction-gear housing and loading of the unit of connecting the housing to the bodies frame have been experimentally evaluated. Findings. On the basis of analysis of the calculation results obtained meeting the requirements of Standards for traction reduction gears with the housings of welded construction by KEVRZ has been found. Originality. Based on the experimental and theoretical investigations, the scientific support of works on developing and putting into operation the renovated traction reduction gears for electric trains of series ER2, ER9 has been completed. Practical value. A technical solution with the measures to be fulfilled in operation of electric trains of the mentioned series with traction reduction-gear housings of welded construction by KEVRZ has been developed and given to experts of Ukrzaliznytsia to introduce the proposed measures during repairs.