Journal of Engineering Sciences / Журнал інженерних наук
Permanent URI for this collectionhttps://devessuir.sumdu.edu.ua/handle/123456789/34326
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Item Simulation of point defects formation in the fuel element of a nuclear power plant’s wave reactor(Sumy State University, 2023) Opyatyuk, V.V.; Kozlov, I.L.; Karchev, K.D.; Vistiak, S.V.; Kozlov, O.I.; Turmanidze, R.This paper considers the point defects that influence the operation of a wav nuclear power reactor with a uranium fuel medium. The formed individual point defects or such defect groups can produce a perturbing effect on the stability of the nuclear reactor operating mode and involve its transition to an unstable state. Studies have been carried out on the effect on the characteristics of the nuclear burnup wave in a medium with neutron multiplication for 2D geometry. For the calculation, the uranium-thorium fissile medium has been considered. The parametric calculations were carried out with 235 U different enrichment percents and different values of neutron activation energy. At that, it was assumed that the wave (flow) reactor stable operation region is located in the range of activation energies from 10–3 eV to 1 eV or in the region from 2 MeV to 8 MeV. When calculating the neutron flux intensity in a wave reactor, the influence of point defects and their aggregates on the decelerating elastically scattered neutrons’ flux density and the flux density of decelerating non-elastically scattered neutrons was considered. The dependences of the point defects formation rate on the medium fissile temperature for several compositions of the uranium-thorium medium are obtained. As visually identified, the graphic materials obtained during the calculations are similar to the photos of fuel rods after the energy campaign.Item Information-extreme machine learning of wrist prosthesis control system based on the sparse training matrix(Sumy State University, 2022) Супруненко, Микита Костянтинович; Супруненко, Никита Константинович; Suprunenko, Mykyta Kostiantynovych; Зборщик, Олександр Петрович; Зборщик, Александр Петрович; Zborshchyk, Oleksandr Petrovych; Sokolov, O.The article considers the problem of machine learning of a wrist prosthesis control system with a noninvasive biosignal reading system. The task is solved within the framework of information-extreme intelligent data analysis technology, which is based on maximizing the system’s information productivity in machine learning. The idea of information-extreme machine learning of the control system for recognition of electromyographic biosignals, as in artificial neural networks, consists in adapting the input information description to the maximum total probability of making correct classification decisions. However, unlike neuro-like structures, the proposed method was developed within a functional approach to modeling the cognitive processes of the natural intelligence of forming and making classification decisions. As a result, the proposed method acquires the properties of adaptability to the intersection of classes in the space of recognition features and flexibility when retraining the system due to the recognition class alphabet expansion. In addition, the decision rules constructed within the framework of the geometric approach are practically invariant to the multidimensionality of the space of recognition features. The difference between the developed method and the well-known methods of information-extreme machine learning is the use of a sparse training matrix, which allows for reducing the degree of intersection of recognition classes significantly. The optimization parameter of the input information description, the training dataset, is the quantization level of electromyographic biosignals. As an optimization criterion is considered the modified Kullback information measure. The proposed machine learning algorithm results are shown in the example of recognition of six finger movements and wrist.Item Rotor dynamics of turbocompressor based on the finite element analysis and parameter identification approach(Sumy State University, 2022) Вербовий, Антон Євгенович; Вербовой, Антон Евгеньевич; Verbovyi, Anton Yevhenovych; Хоменко, Владислав Володимирович; Хоменко, Владислав Владимирович; Khomenko, Vladyslav Volodymyrovych; Neamtu, C.; Pavlenko, V.; Симоновський, Віталій Іович; Симоновский, Виталий Иович; Symonovskyi, Vitalii Iovych; Павленко, Іван Володимирович; Павленко, Иван Владимирович; Pavlenko, Ivan VolodymyrovychThe article is devoted to improving methods for designing a finite element model of rotor dynamics. For this purpose, numerical implementation of the authors’ computer program “Critical frequencies of the rotor” was developed based on the computer algebra system MathCAD. As a result of the scientific work, a refined mathematical model of rotor dynamics using finite beam elements was created. This model considers the dependence of the radial stiffness characteristics of the bearing supports on the values of the critical frequencies. The reliability of the mathematical model was justified by the permissible differences of the obtained results within 2% compared with the results of finite element analysis using the ANSYS software. The theorem was also proven by the mutual location of the spectra of the natural and critical frequencies. Overall, the proposed scientific approach reduces preparation and machine time compared to numerical modeling using the ANSYS software without losing the accuracy of the calculations.