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.

Research of dynamic indicators and influence of different types of rolling stock on railway track

Abstract: The technical level of rolling stock of railway transport directly affects the economic indicators of the transport industry and the economy of the country as a whole, which leads to the need for improvement of the control, quantitative assessment of the dynamic loading o f rolling stock to ensure safe and reliable communication at the railways. Therefore, in the process of designing and operating the rolling stock the quantitative assessment of dynamic loadings is a relevant scientific and technical problem. The purpose of this work is to study the influence of different types of rolling stock, taking into account the speed of movement on their main dynamic indicators and indicators of interaction of track and rolling stock. The basis of the research is the method of mathematical and computer simulation of the dynamic loading of a freight car using the model of spatial variations of the coupling of five cars and a software complex developed in the branch research laboratory of dynamics and strength of rolling stock (BRL DSRS). Theoretical studies have been carried out under condition of movement of several types of freight cars: a gondola car of the model 12-532, a hopper car for coal transportation of the model 12-4034 and a flat car with a long cargo of the model 13-401 and typical bogies 18-100 with the speeds from 50 to 90 km/h in the curves with radii 350 and 600 m, with superelevation 130 and 120 mm, correspondingly.

Constructive Model of the Natural Language

Abstract: The paper deals with the natural language model. Elements of the model (the language constructions) are images with such attributes as sounds, letters, morphemes, words and other lexical and syntactic components of the language. Based on the analysis of processes of the world perception, visual and associative thinking, the operations of formation and transformation of images are pointed out. The model can be applied in the semantic NLP.

3D Modeling of Biological Wastewater Treatment in Aeration Tank

Abstract: Purpose. The main purpose of the article is to develop a 3D CFD model for modeling the process of biological wastewater treatment in an aeration tank. Methodology. For mathematical modeling of the process of biological wastewater treatment in the reactor, taking into account the flow hydrodynamics, geometric shape of the aeration tank, convective-diffusion transfer of the substrate and activated sludge, a 3D CFD model was built. The model is based on the three-dimensional equation of motion of an ideal liquid and the equation of mass conservation for the substrate, activated sludge. The field of sewage flow rate in the aeration tank is calculated based on the velocity potential equation. The process of biological transformation of the substrate is calculated on the basis of the Monod model. The splitting scheme was used for numerical integration of the equations of convective-diffusion transfer of activated sludge and substrate. The splitting is carried out in such a way to take into account the transfer of substrate (activated sludge) in only one direction at each step of splitting. The calculation of the unknown value of the substrate (activated sludge) concentration is carried out according to an explicit scheme. The Richardson method is used to numerically integrate the three-dimensional equation for the velocity potential, and the unknown value of the velocity potential is calculated by an explicit formula. Euler's method is used for numerical integration of equations describing the process of substrate transformation and change in activated sludge concentration (Monod model). Findings. The software implementation of the constructed 3D CFD model is carried out. A description of the structure of the developed software package is provided. The results of a computer experiment to study the process of wastewater treatment in an aeration tank with additional elements are presented. Originality. A new multifactor 3D CFD model has been developed, which allows quick assessing the efficiency of biological treatment in an aeration tank. Practical value. The constructed 3D CFD model can be used to analyze the efficiency of the aeration tank under different operating conditions at the stage of sketch design of wastewater treatment systems.

Study of the effect of soil cement elements when stabilizing roadbed model in laboratory conditions

Abstract: Purpose . Experimental studies allow determining th e stress - strain state or bearing capacity of the tested soil body . A preliminary study of the results of model testing and experimental research allows us to find the optimal solutions and to justify the parameters of the chosen technology. The purpose of this work is to determine the effect of soil cement elements when stabilizing the roadbed on a weak subgrade using the soil tests in laboratory conditions . Methodology . During the development of measures for the reconstruction and consolidation of soil bodies, their strength is tested using many methods. In all cases, we take into account the physical and mechanical characteristics of soils obtained as a result of research, as well as the existing regulatory documents. We performed the experimental studies by model testing in laboratory conditions. The model testing was based on the corresponding relationships between geometric sizes, mechanical properties of materials, loads and other factors on which the stress-strain state depends. During testing, the model was loaded gradually. We maintained each load level up to conditional stabilization of the soil deformation. We took the readings from measuring devices at each stage of loading after achievement of stabilization of soil mass deformations. We fixed the readings in the test journal. Findings . During stabilization with soil cement piles there is an improvement in mechanical properties, which leads to a decrease in deformations by 2…3.5 times. Each test is accompanied with graphs of relative deformations-stress dependence, as well as deformation curves and compression curves. According to the results of experimental stu-dies, it can be seen that when testing a model with cement piles, compared with a model without soil cement piles, the relative deformations of the samples taken prior to the experiment and after the experiment almost coincide, indicating a decrease in deformability under load. Originality . We proved that this stabilization type positively affects the stress-strain state of the soil body, by increasing its physical and mechanical characteristics. The obtained results allow for rational design of subgrade stabilization work with the help of modern technologies . Practical value . The in-depth analysis of the results of experimental studies opens up possibilities for theoretical synthesis and development of theoretical foundations, which will allow in the future avoiding, in the similar cases, the experimental verification of the stabilization type given for the relative type of soil. It is confirmed that this method of stabilization used can be applied in real conditions.

Modern trends of logistics development on the railway market

Abstract: Інтеграція України до транспортної системи ЄС, функціонування міжнародних транспортних коридорів у Європі, зростання транспортних послуг зумовлюють необхідність виявлення низки проблем, пов'язаних із логістичними технологіями. Розвиток залізничної інфраструктури передбачає створення регіональних інформаційно-логістичних центрів, розгалуженої термінальної мережі, що має бути забезпечено шляхом формування інтегрованих систем управління логістичним транспортом. Наведено напрями формування ефективної транспортної логістики на залізничному транспорті, враховуючи велику і всеосяжну приватизацію, яка торкнеться залізниці. Щоб забезпечити приплив капіталу для проведення модернізації «Укрзалізниці», частину акцій держкомпанії необхідно продати іноземним інвесторам, необхідне широке впровадження державно-приватного партнерства, що допоможе створити прозору та ефективну модель бізнесу для залізничного транспорту і в кінцевому підсумку підвищить його конкурентоспроможність. Ключові слова: транспортна система, інтеграція, інфраструктура, логістика, ринок залізничних перевезень, державно-приватне партнерство.