Browsing by Author "Krenicky, Tibor"

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    Calculation of the Probability of Test Object Compliance with the Specified Requirements and Non-Binary Decision-Making Rules
    (MM Publishing s.r.o., Praha, Czechia, 2024) Rimar, Miroslav; Fedak, Marcel; Kulikov, Andrii; Bilonozhko, M. V.; Rudko, K. V.; Martynova, V. V.; Yeromin, Oleksandr O.; Savvin, Oleksandr V.; Sukha, Iryna V.; Krenicky, Tibor
    ENG: The probability of test object compliance with the specified requirements and non-binary decision is a measure of how likely the test object is to meet the criteria for acceptance or rejection based on multiple factors. It is necessary to calculate by using a valid mathematical model that takes into account the test object's characteristics, the test conditions, the test criteria, and the uncertainty of the measurements. The significance of the probability of test object compliance with the specified requirements and non-binary decision can help to evaluate the quality, reliability, and performance of the test object, as well as to support decision making in complex situations.
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    Method of Sequential Approximation in Modelling the Processes of Heat Transfer and Gas Dynamics in Combustion Equipment
    (MDPI, Switzerland, 2022) Rimar, Miroslav; Yeromin, Oleksandr O.; Larionov, Grigoriy; Kulikov, Andrii; Fedak, Marcel; Krenicky, Tibor; Gupalo, Olena V.; Myanovskaya, Yana V.
    ENG: The behavior of the processes taking place in furnaces determines the efficiency of fuel chemical energy utilization, the quality of the final products and the environmental safety of the production. Mathematical models of the processes of gas dynamics and heat transfer in the working space of heating equipment are quite complex, and do not allow the establishment of a direct analytical relationship between the quality indicator of the process (F) and the influencing parameters (xi). To simplify the procedure for obtaining the values of the function F depending on the change of parameters xi, a method of successive approximation is presented in the article. The main idea of the method is that the representation of the function around a point from the domain of the function can be extended to the entire domain for many problems of mechanics. The relative error in the definition of the function acquires its maximum value at the border of the area, and a reasonable narrowing of it allows control of the size of the error. Thus, the advantages of using the method are obvious; it is able to provide approximation of the function in a multiplicative form with a controlled error. The distribution of the method to the field of heat transfer problems is presented in this paper. The successful implementation of this method for solving problems of this kind shows that the solution of practical problems may be generalized for the entire domain of the function, despite the fact that the errors of such a representation increase to 5–7% when approaching its limit, which, however, may be considered acceptable for engineering calculations.
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    Rheological Properties of Polymer-Polymer Mixtures on Corn Starch Base
    (MM Publishing s.r.o., Praha, Czechia, 2022) Rimar, Miroslav; Tretyakoff, Artem; Sukhyy, Kostyantyn M.; Yeromin, Oleksandr O.; Kulikov, Andrii; Fedak, Marcel; Belyanovskaya, Elena; Shunkin, Ihnat; Gupalo, Olena V.; Krenicky, Tibor
    ENG: The prospects for the use of polymer-polymer mixtures based on corn starch as alternative thermoplastic materials to polyolefins are considered. Rheological curves have been obtained, which confirm the possibility of processing such mixtures on standard equipment into products. It is shown that the starch content in polymer-polymer mixtures can reach 90 mass percent. Compared to existing biodegradable polymers, plasticized starch-based material is in no way inferior to them in terms of processability. Studies of the mechanical properties of polymer-polymer mixtures based on corn starch have been carried out. The data obtained indicate the possibility of using the developed composites as packaging materials, as well as alternative materials to known bioplastics and synthetic polymers.