Viktor Skrickij

The dynamic behaviour of a wheel flat of a railway vehicle and rail irregularities

The article examines a mathematical model for the system ‘Railway Vehicle Wheel–Track’ that allows examining the interaction between a wheel flat and a rail in the vertical plane. The dynamics of the railway track is described using the finite element method while that of the soil and vehicle is expressed applying discrete elements. The model is used for assessing physical and mechanical properties, the roughness of the wheel, rail surface and their geometry. The analysis of the dynamic system ‘Railway Vehicle Wheel–Track’ has been conducted. In accordance with the revised method, forces arising from contact between the wheel flat and the rail are possible to be determined in a more precise way. The article presents and analyses the results of a mathematical experiment on this system.

Investigation of Dynamic Processes in Ball Bearings with Defects

The paper considers the dynamics of ball bearings with defects. A mathematical model of a ball bearing with defects is offered. The performed theoretical and experimental investigations of ball bearings with defects are described. Five cases of various defects are investigated, including the defective outer race, the defective inner race, the defective rolling element, the defective inner and outer races, the rolling element and a separator, the worn-out ball bearing.

Investigation of the hydrodynamic processes of a centrifugal pump in a geothermal system

AbstractThe hydrodynamic and thermodynamic processes of geothermal well extraction are investigated and presented in this paper. The paper presents mathematical models for a multi-level centrifugal pump and pipeline system. The mathematical models were used to evaluate gas (nitrogen) emission in water and its effects on hydrodynamic processes. Experimental studies and mathematical modelling showed that the gas content of the fluid increases the pressure and flow pulsations within a centrifugal pump. The variation in the height of the liquid column in extraction has an influence on characteristics of the multistage centrifugal pump used in wells.

A MODEL TO EVALUATE SUPPLY CHAIN TECHNOLOGY IMPLEMENTATION INFLUENCE ON ORGANIZATIONAL PERFORMANCE

Supply Chain Management (SCM) aims to achieve organizational competitiveness. By including SCM paradigm and Information Technology (IT), companies aim to enhance their responsiveness and flexibility, and by changing their operations’ strategy, they attempt to improve their competitiveness. This study focuses on the organizational variable, IT capabilities, technological structure, and possible antecedents and their impact on Supply Chain Technology (SCT) implementation. This paper proposes a model to examine the way, which SCT implementation affects IT enabled Organizational Performance (OP). The data were achieved through the questionnaires, and then they were analysed by using Smart PLS 3 program. The data collected from 118 employees in IT sector of Iran’s customs administration provide strong support to the proposed research model. The results of this research showed that SCT implementation has a mediating effect on IT enabled OP improvement. Besides, the study revealed that IT capabilities have the most and organizational variable has the least influence on implementation of SCT. Based on other organization’s situations, they can use the suggested model with a little changes.