Browsing by Author "Zadoia, Viacheslav O."
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Item 3D Modeling of Biological Wastewater Treatment in Aeration Tank(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2020) Biliaiev, Mykola M.; Lemesh, Maksym V.; Gunko, Olena Y.; Zadoia, Viacheslav O.; Mashykhina, Polina B.; Yakubovska, Zinaida M.ENG: 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.Item Government Strategy for Enhancing the Infrastructure of International Freight Railway Corridors: Economic and Strategic Considerations(Learning Gate, Brooklyn, NY, USA, 2025) Tymoshchuk, Yaroslav; Hrebeniuk, Halyna M.; Selishchev, Sergii; Suray, Inna; Zadoia, Viacheslav O.ENG: The article examines the state strategy for developing the infrastructure of international freight railway corridors in the European and Asia-Pacific regions from 2022 to 2023. It considers the impact of public investment on the formation of infrastructure projects through macroeconomic analysis. It describes programs that help optimize freight transport and stimulate trade development between continents. Public investment in the infrastructure of railway corridors in the EU has increased by 12% over the past five years, indicating a strategic interest in their further development. The article highlights the essence of international partnership and trade cooperation based on foreign investment to modernize railway networks. Special attention is paid to the strategic infrastructure goals for logistics corridors and transport hubs. The role of railway corridors passing through China and the European Union territory is identified. The competition between regions for leadership in transit hubs, economic influence, and control of transport corridors is investigated. At the micro level, trends in the formation of modal transport and the construction of heavy railway infrastructure are analyzed. The efficiency of the G7 countries in increasing the capacity of freight networks is studied. The problems of the states with regulatory protectionism measures have been identified. The article provides a comparative analysis of the leading companies in global freight corridors that are of strategic importance for the functioning of the economy.Item Integrated Approach to Marketing Strategies in the Startup Industry(Дніпровський державний аграрно-економічний університет, м. Дніпро, ТОВ "ДКС Центр", 2024) Zadoia, Viacheslav O.; Charkina, Tetiana Yu.ENG: The study analyses and evaluates marketing strategies that can be used by startPup companies to ensure rapid growth, attract customers and create a brand identity. The following methods were used to achieve the goal and solve these problems: statistical analysis: to process and interpret data related to marketing strategies and their impact on the success of startups; theoretical analysis: consideration of existing knowledge, theories, and models in the field of startup marketing and analysis of scientific papers, articles, and other publications, which allows to summarise existing approaches and concepts; economic and mathematical modelling: to evaluate different marketing strategies and determine their potential effectiveness. The developed multiPcriteria optimisation model helps to choose the optimal strategy, taking into account various determinants such as budget, time, resources, profit, risks, etc. This model allows to systematise the decisionPmaking process and more objectively evaluate and compare different alternatives, maximise overall efficiency by choosing among alternative strategies those that best meet the conditions and goals of the company. Scientific novelty: an integrated approach to marketing strategies for startPup companies is proposed, taking into account modern digital trends. A multiPcriteria model for optimising marketing strategies using economic and mathematical modelling has been developed, which opens up new opportunities for effective strategy selection in the context of limited resources and high uncertainty inherent in this business model. Practical significance. The implementation of an integrated approach allows providing recommendations for the development and implementation of effective marketing strategies for startPup companies, venture capital funds and accelerators. Particular emphasis is placed on the use of analytical methods, such as economic and mathematical modelling, to optimise marketing decisions. The use of this approach provides practical tools for identifying target markets, efficient allocation of resources and minimising risks.Item Marketing Management at Railway Transport Enterprises(РС Тесhnology Сеntеr, Kharkiv, 2023) Charkina, Tetiana Yu.; Zadoia, Viacheslav O.; Dmytriieva, ОksanaENG: The monograph pays attention to the problems and prospects of innovative development of the road and transport complex. In Ukraine, the road and transport complex is classified as a priority system. And taking into account its key role in the defense of the state, the need to carry out scientific developments and practical recommendations for the development of the road and transport system as a whole is becoming urgent. Factors affecting the transport infrastructure of the area and the economic consequences of their implementation have been systematized, and a system of management of the transport infrastructure has been developed. The stages of formation and implementation of entrepreneurial strategies, which determine the sustainable innovative development of road and railway transport enterprises, have been developed. The methodical approach to the development of the list of indicators of preventive anti-crisis management of the road enterprise has been improved thanks to the comprehensive consideration of the results of the study of the quantitative and qualitative composition of the indicators of the CVP analysis. The personnel management system of the motor vehicle enterprise has been formed on the basis of a holistic approach, and a methodology for assessing the effectiveness of the enterprise's personnel control was proposed, which helps to identify the weakest points in the existing control system. In order to determine the objects of innovative activity, the urgency and timeliness of the application of functional-cost analysis has been proven. In order to achieve an economic and ecological effect in defined strategy improve cars for earthy road construction works. The proposed theoretical, methodological and applied aspects of the development of the road and transport complex are of theoretical and practical interest for scientists, entrepreneurs and state administration bodies.