Browsing by Author "Stupak, Yurii O."

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    Features of Using the Distance Learning Model
    (Ukrainian State University of Science and Technologies; Aalto University Helsinki, Finland, 2021) Shvachych, Gennady G.; Khokhlova, Tetiana S.; Stupak, Yurii O.; Moroz, Boris; Kabak, Leonid
    ENG: Purpose. To analyze models of distance learning (DL) that have been implemented in the world and have shown effectiveness in order to determine promising directions for the development of DL: testing, educational research, contextual learning, mobile learning, development of social networks, application of mobile educational games, implementation of mobile voice content with interactive assessment etc. Methodology. Literature review of open access information sources. Findings. It has been determined that special attention should be paid to the technologies of educational institutions, in which it is possible to involve highly qualified teachers in reading lectures; there is a significant saving of teachers' time; there is a possibility of increasing the amount of material presented within the budget allocated for regular classroom activities in the curriculum. Originality. It consists in a certain set of criteria, based on the analysis, which are necessary and sufficient to achieve the final goal. Practical value. The methods of selection of educational tools make it possible to increase the effectiveness of the educational process, make it attractive and exciting for students and motivate them to an active educational process always and everywhere, which allows students to receive a quality education.
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    On Some Aspects of the Study of Pulverized Coal and Fuel Mixtures Combustion in a Drop Tube Furnace
    (НМетАУ, Дніпро, 2021) Stupak, Yurii O.; Khokhlova, Tatyana S.
    ENG: Analysis of the operation of fluid friction bearings (FFB) of mills 630 showed that the loss of oil on the cages 630 reaches up to 10 tons per year. The reason for this is the imperfection of the seal design, which in turn does not provide the required mode of lubrication of the FFB and leads to high-intensity wear of the surfaces of the sleeve and bearing liner. Which leads to the failure of the FFB before the deadline for replacement of the sleeve and liner. The aim of the study is to determine the load of FFB by mathematical modeling to determine the energy and power parameters of rolling on the example of channel No14, determine the coefficient of friction, study the wear of the surface of the sleeve and liner FFB and provide recommendations for possible ways to improve FFB seals 630. To determine the energy and power parameters of the rolling profile of the channel profile, mathematical modeling was performed using the software product QForm 9. The QForm program is designed for mathematical modeling, based on the finite element method, technological processes of metal forming by taking into account thermomechanical processes of heating and cooling of metal, including in the process of deformation, as well as the interaction of the deformable workpiece with technological tools and equipment. The greatest rolling forces and, accordingly, the load on the FFB will act in the cage No4 and reach 2.8 MN when the roll is captured. The obtained result indicates that the increase in the load acting on the bearing does not significantly affect the change in the coefficient of friction in it, which is in the range of 0.0027 - 0.00274. The value of the friction coefficient μ will be most affected by the viscosity of the oil η and the value of the radial gap δ. The calculation confirmed the transition to the maximum friction during wear to a radial gap of 4 mm, which was observed during the operation of the FFB. The value of the gap δ = 1.8 mm, at which the replacement of the liner and the bearing sleeve will be obtained after 8.8 years of operation. But operational data show that such a gap is reached in 3 years of operation. The reduction in bearing life is due to inadequate friction, namely non-compliance with the viscosity parameters of the oil and its insufficient amount in the bearing. The reason for this is the leakage of oil due to unreliable sealing and ingress of abrasive and coolant rolls. An improved design of seals using V-shaped cuffs is proposed.
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    Structural Materials for Elements of Nuclear Reactors Equipment
    (National Science Center, Kharkov Institute of Physics and Technology, Kharkiv, 2025) Pylypenko, M. M.; Yefimov, O. V.; Drobyshevska, A. O.; Stupak, Yurii O.
    ENG: The paper presents the main results of research on the development of structural materials for equipment elements of existing and prospective nuclear power plants. The further development of nuclear energy largely depends on the development of advanced structural materials for new generation reactors and the improvement of materials for operating nuclear power plants. The results of research on the optimization the iron content of the zirconium alloy to increase corrosion resistance in the coolant and resistance to radiation growth are presented. Experimental determination of the laws of the behavior of impurities during the refining of chemically active and refractory metals made it possible to achieve a higher level of metals purity. It is shown that nickel alloys of the Hastelloy type, obtained from high-purity metal components, can be successfully used as a structural material of the MSRs. The high requirements for structural materials regarding the content of impurity elements can be met only when high-purity metals are used as initial components and new technologies for their production are used.
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    Use of Artificial Intelligence as an Element of Student’s Cognitive Activity Activation during the Lecture
    (Ukrainian State University of Science and Technologies; Jourfond, 2023) Stupak, Yurii O.
    ENG: Purpose. Show the possibilities provided by the use of the artificial intelligence (AI) model - the language model ChatGPT (version 3.5) from the Open AI company to activate the cognitive activity of students during lectures. Methodology. Application of ChatGPT (version 3.5) during online lectures and collective search for possible inaccuracies in AI answers, based on previously acquired theoretical knowledge of the discipline. Findings. It is shown that the use of AI during online lectures can significantly revive the cognitive activity of students and their interest in the material of the lectures and increase the quality of assimilation of sections of disciplines that are difficult for students to perceive and, as a result, the quality of the formation of key competencies and program learning outcomes. Originality. Using the AI model as an active participant in the educational process and discussions on intricate issues of the academic discipline. Practical value. It is shown that the use of AI systems similar to ChatGPT in the educational process can be very useful in terms of modernizing didactics and learning design and can be applied in the online educational process.
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    The Use of X-Ray Research Methods to Clarify the Degree of Pulverized Coal Particles Thermal Destruction during Combustion under Conditions of It Injection into a Blast Furnace
    (National Metallurgical Academy of Ukraine, Dnipro; Technical University of Varna, Bulgaria, 2021) Stupak, Yurii O.
    ENG: Purpose. To show one of the ways of using X-ray research methods to find out the degree of thermal destruction of pulverized coal particles during combustion under the conditions of blowing them into a blast furnace, as well as the effectiveness and informativeness of the proposed method. Methodology. A common method of X-ray structural analysis or X-ray diffraction (XRD) is applied, which allows to calculate structural parameters (interplanar distance and size of crystallites) of carbon materials directly from their diffraction patterns, which determine their structure. The diffractogram for pure graphite is used as a reference for comparison, comparing the reflections for the principal planes (hkl) - 002, 100, 101 and 004. Findings. A qualitative comparison of the obtained X-ray diffractograms showed that the addition of gaseous coal and peat to pulverized coal dust from lean coal affects the process of its combustion, but the nature of the action of these additives is different. For the burned lean coal and the burned mixture of lean coal with gas coal, the shape (width at half maximum) and the location of the characteristic maxima on the radiograph practically coincide. For the sample burned with the addition of peat, the half-width of the main maximum and the intensity of the maxima in the region of far corners differ from those for coal burned with and without the addition of gas coal. Originality. It consists in combining the laboratory method of modeling the combustion of pulverized coal particles in a blast furnace based on the laboratory "drop furnace" (drop furnace) with the proposed method. Practical value. It is shown the possibility of using the X-ray diffraction method in combination with other research methods in the evaluation (selection) of pulverized coal fuel and its additives for blowing into a blast furnace in order to achieve the best results in terms of the degree of combustion. and equivalent replacement of coke.