Browsing by Author "Mazorchuk, Volodymyr F."

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Assessing Criteria for Casting and Deformation Suitability of Metals and Alloys
(Dnipro University of Technology, Dnipro, 2025) Kimstach, Tetiana V.; Uzlov, Kostiantyn I.; Bilyi, Oleksandr P.; Mazorchuk, Volodymyr F.; Repyakh, Serhii I.
ENG: Purpose. Based on existing criteria for predicting the suitability of metals and their alloys for manufacturing products from them by deformation or casting analysis develop a set of dimensionless parametric criteria and their quantitative scales. Their using will allow increasing the predicting accuracy of metals and alloys for their processing by pressure or casting suitability and feasibility. Methodology. The work uses phenomenological approach to systematic analysis results of metals and alloys mechanical and individual casting properties interpreting under uncertainty conditions, drawing on literature reference data, expert evaluation data and the authors’ own research results. The authors’ own data have been obtained experimentally using standard methods for mechanical properties determining and due to original authors’ method for technical purity metals and alloys based on them cast samples values of their absolutely hindered linear shrinkage determination during casting. Findings. The authors first proposed parametric dimensionless criteria and scales to them (criteria groups). Their application allows one, through such groups combinations, to assess suitability of any alloy or metal for its use possibility for products manufacturing by casting and/or pressure processing. Originality. For the first time dimensionless parametric criteria have been developed and proposed for use at initial stages of new alloys or technologies elaboration for products from them manufacturing as well as their quantitative scales for preliminary assessment (prognosis) of alloys processing feasibility by pressure or casting, regardless of their type and method. Practical value. Developed criteria and their quantitative scales using will allow alloys developers and specialized enterprises employees to save time and expenses both for alloy elaboration and for its implementation into production.
Improvement of Energy Efficiency and Environmental Safety of Internal Combustion Engines by Using Binary Fuel Mixtures with Hydrogen
(Ukrainian State University of Science and Technologies, Dnipro, 2025) Bartashevskyi, Stanislav; Koveria, Andrii; Ovcharenko, Alina; Mazorchuk, Volodymyr F.
ENG: This paper addresses current issues related to improving the efficiency of fuel use in internal combustion engines and reducing the environmental impact of fuel combustion. It is demonstrated that incorporating hydrogen into mixtures with liquid fuels enhances the fuel’s energy potential and combustion completeness. This approach aligns with the goals of sustainable development by reducing reliance on liquid hydrocarbon fuels and mitigating the harmful effects of pollutant emissions. The study proposes producing hydrogen via chemical reactions directly at the point of use, in quantities required for operation. These reactions enable the use of readily available, non-toxic materials for the targeted generation of hydrogen and its incorporation into fuel mixtures. Calculations show that the energy consumption for decomposing 1 kg of water using diesel and AI-92 gasoline is 12.9 MJ/kg and 13.2 MJ/kg, respectively.
Step-by-Step Analysis of the Condition of the Side Tunnel for a Pylon-Type Metro Station under Construction NATM
(IOP Publishing Ltd, 2026) Radkevych, Anatolii V.; Kuprii, Volodymyr; Dubinchyk, Olha I.; Mazorchuk, Volodymyr F.
ENG: This scientific research provides a step-by-step analysis of the condition of the side tunnel for a pylon-type metro station with combined lining. An analysis of the algorithm for applying the New Austrian Tunneling Method to the construction of underground structures in hard rocks (as in the Dnipro Metro) has been conducted. It is justified that the analysis of the stress-strain state in the combined lining for the side tunnel of a station should be carried out in accordance with the stages of opening the working and installing the combined lining. A finite element model has been developed to represent the stages of side tunnel construction. This model also reflects the station structure’s conditions, its dimensions, and the interaction between the combined lining and the surrounding rock massif. The dependences of horizontal stresses in the rock massif and the bending moment in the combined lining on the stage of construction of the side tunnel have been obtained. The conclusion from the step-by-step analysis in the construction of the side tunnel for a pylon-type metro station, built using the New Austrian Tunneling Method, is that maximum stresses and force factors occur during construction rather than during the operational phase.
Structural Formation Regularity of Cu-Sn-Si System Low-Tin «Singing» Bronze
(Baltija Publishing, 2022) Uzlov, Kostiantyn I.; Mazorchuk, Volodymyr F.; Dziubina, Alina V.
ENG: Based on the task of acoustic bronzes containing about 20%Sn cost reducing, the aim of economically alloyed bronze composition with expensive tin replacement by silicon developing has been formulated in the present work. Three-component system Cu-Sn-Si bronzes structure formation has been studied and conodes triangle copper corner alloys phase transformations regularities were determined. It was established that in Cu-Sn-Si system alloys with Si content more than 4wt.%, original β-phase is stabilized by silicon and in solid state does not undergo low-temperature eutectoid transformations with small (up to 4wt.%) tin amount in bronze. It is shown that this «singing» bronze structural state is the basis for two systems of structural stresses in castings body existence, which act as acoustic resonators in products material. These systems are: α-Cu solid solution liquated areas of different genesis and interphase boundary α-Cu↔β-Cu5Sn, which causes occurrence of II type internal structural stresses between α-Cu and chemical compound Cu5Sn, which are fundamentally dissimilar in nature. For the first time, with comprehensive using of scanning electron microscopic, X-ray spectral, energy dispersive, X-ray structural phase and metallographic studies of Cu-Sn-Si alloys with optimized composition (silicon 4.5...5.5% by mass and tin 2...5% by mass at mass ratio Si/Sn≥1), tin-silicon bronzes with main components optimal ratio structural formation regularities are established. New bronze for bells and percussion musical instruments in terms of strength and impact toughness exceeds «classical» bell bronze indicators by~1.5...2.5 times with comparable relative elongation values. This evidences that, compared to «classic» bell bronze, elaborated cast bronze products with developed optimal chemical composition are characterized by greater reliability and durability during operation within its application specified area. Present work innovative solutions on methods of making musical bronze, obtaining bronze castings and making bells and percussion musical instruments acoustic elements are covered by intellectual property protection documents.