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.

Modeling of temperature fields in a solid heat accumullators

Abstract: Purpose . Currently, one of the priorities of energy conservation is a cost savings for heating in commercial and residential buildings by the stored thermal energy during the night and its return in the daytime. Economic effect is achieved due to the difference in tariffs for the cost of electricity in the daytime and at night. One of the most common types of devices that allow accumulating and giving the resulting heat are solid heat accumulators. The main purpose of the work: 1) software development for the calculation of the temperature field of a flat solid heat accumulator, working due to the heat energy accumulation in the volume of thermal storage material without phase transition; 2) determination the temperature distribution in its volumes at convective heat transfer. Methodology . To achieve the study objectives a heat transfer theory and Laplace integral transform were used. On its base the problems of determining the temperature fields in the channels of heat accumulators, having different cross-sectional shapes were solved. Findings . Authors have developed the method of calculation and obtained solutions for the determination of temperature fields in channels of the solid heat accumulator in conditions of convective heat transfer. Temperature fields over length and thickness of channels were investigated. Experimental studies on physical models and industrial equipment were conducted. Originality . For the first time the technique of calculating the temperature field in the channels of different cross-section for the solid heat accumulator in the charging and discharging modes was proposed. The calculation results are confirmed by experimental research. Practical value . The proposed technique is used in the design of solid heat accumulators of different power as well as full-scale production of them was organized.

Modeling coal dust dispersion from pile with protection barriers

Abstract: The results of laboratory studies to evaluate the effectiveness of barriers which are used to reduce dust pollution from the coal pile are presented. The use of the Г-shaped barrier, which is set differently near the coal pile model, has been studied. A numerical model is proposed to compute coal dust concentration in the air near the pile. The Navier–Stokes equations are used to model the wind flow over the coal pile. These equations are written in the variables “vorticity-stream function”. To simulate the process of coal dust dispersion from the coal pile, the equation of convective-diffusion transfer of the passive impurity is used. For numerical integration of the modeling equations, difference schemes of splitting are used. Developed numerical model allows to perform numerical experiments taking into account the complex geometric shape of the pile and screens. The results of the computational experiments are presented.

Quantum Mechanical Approach for Determining the Activation Energy of Surface Diffusion

Abstract: A quantum mechanical approach was proposed to determine the activation energy of surface diffusion for copper, nickel, zinc and iron atoms adsorbed on a copper substrate during electrocrystallization for various overvoltages of the substrate. The activation energy of surface diffusion was calculated from the crystal total energy. An increase in the activation energy of surface diffusion with increasing surface potential is associated with an increase in the binding energy between the ad-atom and the substrate.

Remote work format of university libraries. comparative characteristic of the software for digital scientific communication

Abstract: Objective. Research of the experience of mass implementation of the remote format of work in Ukrainian university libraries during the period of isolation caused by the COVID-19 pandemic, analysis of work in various communication systems and programs. Evaluation of the possibility of the most optimal choice of software for remote working. Methods. We used the analysis and interpretation of the data of the work of six applications used in organizing remote work in the university library: Hangouts, Zoom, Meet, Microsoft Teams, Skype, and Viber. The combination of analytical and practical research methods made it possible to optimize the choice of software for the remote format of work of university libraries during the isolation period. Results. The study of the use efficiency of Hangouts, Zoom, Meet, Microsoft Teams, Skype, Viber, as well as a survey conducted during the pandemic of the opinions of employees of the scientific and technical library of the Dnipro National University of Railway Transport (DNURT) on the experience of remote work, made it possible to identify the main difficulties in organizing remote work of the library. The practice of applying and mastering application programs of digital communication revealed the potential of remote work of the university library and played the role of a catalyst in the development of a remote work format. Conclusions. To conduct a high-quality online webinar for free, you need to decide on a service that is time-tested and has a good reputation among users. It will be reliable, provide all the necessary functionality for the implementation of high-quality online content. It is important to read as many feedbacks as possible.

Theoretical and experimental evaluation of strength indices of bogie frame transoms for trailing cars of electric trains ER9M, ER9E

Abstract: Purpose. The article objectives are to identify the factors, which can contribute to the formation of cracks and to develop the measures on improving the strength indices of bogie frame transoms of trailing cars. Methodology. In order to achieve these objectives, in performing the work it was conducted the inspection of the technical condition of supporting structures for bogie frames of trailing cars; measured the Brіnell hardness numbers and estimated the endurance limits of transom material; tested on determination of the levels of efforts and stresses being created in the specified transoms under operation; developed the computational models for the theoretical determination of stress levels in the transom by simulating both normal and abnormal conditions of operating loading. Findings. Based on the analysis of results obtained: the situations with the highest stress levels were found; the measures on improving the strength indices of bogie frame transoms of trailing cars were developed. Originality. Based on the experimental and theoretical studies, the scientific monitoring of works to develop the measures on improving the strength indices of bogie frame transoms of trailing cars was carried out. Practical value. The developed measures on improving the strength indices were passed to professionals of Ukrzaliznytsia to introduce the proposed activities during the repairs of electric trains of specified series.