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Adhesion Strength of Electrodeposited Ni, Zn, and Fe Coatings with Copper Substrates
(Taylor & Francis Online, 2022) Shtapenko, Eduard Ph.; Zabludovsky, Vladimir A.; Tytarenko, Valentyna V.
ENG: This paper presents the adhesive strength values of electrodeposited nickel, zinc, and iron coatings on copper substrates at various deposition parameters, including laser-assisted stimulation of the deposition process. One of the factors determined to be responsible for the adhesive strength of metal films with a metal substrate is the formation of a diffusion zone at the ‘coating-substrate’ interface. It is shown that an increase in adhesive strength is achieved due to the expansion of the diffusion zone and the formation of solid solutions. The decrease in adhesive strength at high overpotentials is associated with the release of hydrogen and the formation of intermediate phases.
Analysis of Air Dust Pollution in the Transport Compartment of the Launch Vehicle at the Stage of the Pre-launch Preparation
(Printing House “Technologija”, Kaunas, Lithuania, 2024) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia V.; Mashykhina, Polina B.; Semenenko, Pavlo
ENG: At the stage of the pre-launch preparation, it is necessary to fulfill very strict environment conditions inside the main fairing where the satellite is located. Namely, it is very important to predict dust concentration inside the main fairing and especially near satellite surface during forced ventilation. To predict air dust pollution inside of main fairing 2D fluid dynamics numerical model has been developed. The governing equations include equation of potential flow to simulate air flow inside the main fairing and equation of pollutant dispersion. Also, empirical model has been used to calculate the number of dust particles fall to the satellite surface. Implicit finite difference schemes of splitting have been used for numerical integration of governing equations. The computer code has been developed on the basis of proposed numerical model. The results of computational experiments to estimate dust concentration field inside the main fairing of the launch vehicle are presented.
Assessment of Radioactive Contamination Level of Environment in Case of Accident at Nuclear Power Plant
(IOP Publishing Ltd, 2023) Biliaiev, Mykola M.; Rusakova, Tetiana I.; Dziuba, Serhii V.; Lapshin, Yevhen; Koval, Natalia
ENG: The accidents at nuclear power plants pose a particular threat to the population and the environment. Accidental emissions at nuclear power plants can cause long-term radioactive pollution of the environment, and the elimination of such pollution can take years. For practice, it is very important to predict the intensity and size of radioactive contamination zones for various scenarios of extreme situations at the nuclear power plants. Such a forecast will identify the most vulnerable areas and develop a response strategy to the situation that has arisen. A numerical model has been built that allows to quickly predict the scale of radioactive contamination of the territory during an emergency release at a nuclear power plant. The model is based on the application of implicit difference schemes for the numerical integration of the equation of convective-diffusion transport of impurities in the atmosphere. The developed model is characterized by the calculation speed. The results of the computational experiment are presented.
CFD Modeling of Traffic-related Air Pollution in Street Canyon
(Printing House “Technologija”, Kaunas, Lithuania, 2024) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia V.; Yakubovska, Zinaida M.
ENG: High pollution levels are often observed in urban street canyons. Different mathematical models are intensively used to predict pollution levels in urban street canyons. In this paper quick computing 3D CFD model is proposed to compute wind flow over buildings and pollutant dispersion in street canyon. To simulate wind flow over buildings 3D equation of potential flow has been used. Pollutant concentration field has been modelled using three-dimensional equation of pollutant dispersion. Governing equations are also included simplified equations to describe pollutants chemical transformations in atmosphere. To solve numerically governing equations implicit difference schemes have been used. The computer code to realize the proposed numerical models has been developed. Results of numerical experiments are presented.
Complex Diagnostics of Concrete Lining Technical Condition
(IOP Publishing Ltd, 2023) Skipochka, Serhii; Serhiienko, Viktor; Amelin, Volodymyr; Amelina, Larysa V.
ENG: The main use of concrete lining is mine and hydraulic engineering construction. The options of its use in underground structures and mining operations have been considered. The advantages of this lining during construction and operation have been reflected. A long service life of underground facilities with concrete lining in Ukraine has been noted. The typical defect types have been identified. The main reasons for defect formation have been reflected. The impact of natural factors on the deterioration of the lining has been researched. The possible consequences of the flaw growth have been reported. Limited opportunities for visual inspection of the concrete surface have been noted. The main areas of non-destructive test of linings have been analyzed. The basic set of methods and control devices have been established. Special features of monitoring with various methods have been indicated. The main requirements for the registration of primary data have been defined. Typical options of office data processing have been outlined. According to the processing results, the category of the technical condition of the lining is determined. Criteria for assessing the technical condition have been presented. Specific examples of complex examination of concrete lining have been provided.
Composition Variations and UV Irradiation Effect on Charge Transfer in PbMoO4 Single Crystals
(Oles Honchar Dnipro National University, 2022) Bochkova, Tatiana; Trubitsyn, Mykhailo P.; Volnianskii, M. D.; Volnyanskii, Dmytro M.
ENG: The effect of nonstoichiometry of the composition, PbO polymorphism, and preliminary irradiation with ultraviolet light on electrical conductivity of alternating current (AC) was studied in PbMoO4 crystals. The crystals were grown by Czochralski method in a direction deviated by 30° from a-axis in (001) plain. The charge was prepared from MoO3 and PbO, lead oxide was used of α- or β- structural modifications. The reagents were taken both in a stoichiometric ratio and with an excess of 0.5 mol % of MoO3. It was shown that the magnitude of the dark and irradiation-induced AC conductivity was affected both by the type of polymorphic form of PbO and by the excess amount of MoO3. The influence of the PbMoO4 crystal structural disorder on charge transfer processes are discussed within the framework of the model of hopping conduction in disordered media.
Construction of a Mathematical Model of the Heat and Mass Transfer Process in the Main Fairing of a Launch Vehicle at the Pre-Launch Preparation Stage
(TECHNOLOGY CENTER PC, Kharkiv, 2025) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Rusakova, Tetiana I.; Kozachyna, Vitalii A.; Semenenko, Pavlo V.; Berlov, Oleksandr V.; Kirichenko, Pavlo S.; Hrudkina, Nataliia S.; Voitenko, Yuliia V.; Dolzhenkova, Olena V.
ENG: This study investigates the sequential and continuous formation of thermal fields in the main fairing of a launch vehicle when using protective screens. While thermostating, it is necessary to predict the risk in overheating the payload body and, if necessary, take measures to reduce the temperature near the payload. An engineering solution to this problem can be found through the use of protective screens of various configurations inside the main fairing. These screens reduce the heat flow from the heated outer wall of the fairing to the payload surface. However, there are no standard methods for solving this problem. To evaluate the effectiveness of this protection, a numerical model based on the fundamental equations of continuum mechanics has been constructed. The modeling equations include the energy equation and the equation of motion of a non-viscous gas. Using the numerical model built, a computational experiment was conducted, which confirmed the effectiveness of using protective screens to shield the payload body from excessive heating. The computer time required to perform the computational experiment is 3 seconds. This makes it possible to perform a significant number of calculations in a working day. The proposed simple technical means for protecting the payload from excessive heating could be used in the design of new models for rocket technology. Applying these screens slightly reduces the need for large volumes of clean air. The numerical model built could be used at specialized organizations at the “for-sketch” design stage. Numerical experiments have shown that the use of protective screens inside the main fairing makes it possible to achieve a temperature 2–4°C lower than the maximum permissible temperature near the payload.
Defining Dust Load Patterns and Assessing Health Risk to People from Traffic Flows near a Quarry
(PC "Technology center", 2025) Rusakova, Tetiana; Rusakova, Kateryna; Voitenko, Yuliia; Dolzhenkova, Olena; Zolotko, Olena; Gunko, Olena Yu.
ENG: This study investigates atmospheric dust pollution generated by quarrying activities, particularly the impact of traffic on access roads. The task addressed relates to the lack of a comprehensive assessment of dust levels and associated health risks, considering the actual operation of quarry infrastructure and seasonal variability. Emissions from quarrying during 2020–2024 have been analyzed, which made it possible to evaluate anthropogenic pressure. PM2.5 and PM10 measurements were conducted along the access road to the Rybalskyi quarry (Ukraine); the results were used for statistical processing and dust load modeling. Correlation-regression models were built to assess the impact of environmental and transport factors, identifying key pollution drivers. A mathematical model of the spatial distribution of concentrations was constructed, including an evaluation of health risks for people. Maximum recorded PM10 concentrations reached 312 μg/m3, thereby exceeding the permissible limit by 6.2 times. Considering meteorological conditions, vehicle types, as well as traffic intensity enabled quantitative assessment of each factor's contribution to dust load and identification of high-risk zones. The results are attributed to the high sensitivity of dust concentrations to local changes, confirmed by determination coefficients and spatial modeling outcomes. The proposed approach is suitable for environmental protection measures aimed at reducing dust emission impact on the environment and public health. It could be applied to plan sanitary-protection zones, regulate traffic, and optimize logistics according to local conditions. This approach requires the availability of meteorological data and traffic information to provide reliable forecasts
Environment Pollution Modeling on the Base of Quick Computing Models
(Ukrainian State University of Science and Technologies, 2025) Rusakova, Tetiana I.; Berlov, Oleksandr V.; Gubin, O. I.; Gunko, Olena Yu.; Mashykhina, Polina B.
ENG: Purpose. Development of a fast calculation models for determining zones of ground waters and air chemical pollution during the emission of chemically hazardous substances from anthropogenic sources of pollution. To mod-el the process of passive impurity transfer in ground waters and in atmospheric air, the G. Marchuk model is used, which takes into account the speed and direction of the flow, the intensity of the emission of chemically hazardous substances, and atmospheric diffusion (dispersion in round waters). Methodology. The process of ground waters and air pollution modeling is based on the numerical integration of the mass transfer equation (G. Marchuk model). Two numerical models were built. One numerical model was built to simulate ground waters pollution. Another numerical model was built to simulate air pollution. The construction of a numerical models of the impurity propagation process was carried out by splitting of the mass transfer equation (G. Marchuk model). Then a variable-triangular finite-difference decomposition schemes were used for numerical integration. The unknown value of the concentration of a chemically hazardous substance is carried out using explicit formulas. A set of applied programs has been developed based on the constructed numerical models. Findings. A set of applied programs has been developed based on the constructed numerical models. The results of numerical calculations are presented, showing the efficiency of the proposed numerical models. Originality. Proposed numerical models of mass transfer allow to compute quickly the areas of chemical air pollution due to the emission of toxic substances from anthropogenic sources of pollution. Practical value. Based on the proposed numerical models, a computer code has been developed. The developed models and computer code make it possible to estimate the size and intensity of environmental pollution, and can be used in solving the problem of assessing the negative impact on the ground waters and air from different sources. The results of numerical calculations show the operability of the proposed models.
Evaluation of Gabions Usage Effectiveness for Industrial Facilities Protection Against Damage
(Український державний університет науки і технологій, Дніпро, 2025) Medvedieva, Olha O.; Dziuba, Serhii V.; Kalashnikov, Ivan V.; Biliaiev, Mykola M.; Kozachyna, Vitalii A.
ENG: Purpose. In the extreme situations at industrial sites, various damaging factors may appear, such as the spread of toxic substances in the air, the creation of a fireball, etc., which pose a threat to the lives of workers and have a significant negative impact on the environment. That is why today, special attention is being paid to the problems associated with the spread of debris during a drone attack. At an industrial site where oil product storage facilities are located, the debris generated during an explosion can damage the tank building and cause a fire. In this regard, the main objective of the study is to evaluate the effectiveness of using gabion to reduce the risk of damage to the oil storage facility during the movement of drone debris. Methodology. To achieve this goal, the paper considers the problem of flying debris in the event of a drone explosion at an industrial site where oil storage facilities are located. The use of gabion with sand is proposed to protect the tank building from the throwing effect of debris. It is proposed to develop a mathematical model of the movement of a fragment in the path of which the gabion is located. The effect of gabion as a protective screen on reducing the air temperature near a neighboring oil storage facility in the event of a fire at an industrial site is also considered. A model of the dynamics of a point motion (Newton's second law) was used to mathematically describe the movement of the debris. Numerical integration of the modeling equations was performed using the Euler's method. The energy equation was used to model the process of thermal air pollution at an industrial site during a fire. Findings. In this work, the numerical model was programmed and a computer code was created. The programming language is FORTRAN. The code provides information on the speed of the fragment movement in different parts of each zone. On the basis of the constructed numerical model and the created code, parametric studies were carried out to determine the effectiveness of using gabion with sand to protect the oil storage facility from the effects of fragment. As an approximation, the case when the fragment after the explosion moves horizontally in the direction of the object was considered. The influence of the gabion height on the heating level of the wall of the oil storage facility located at an industrial site was analyzed. Originality. An effective mathematical model has been developed to evaluate the effectiveness of using gabion to protect the oil storage facility from damage by drone fragment. The proposed model allows determining the rational dimensions of the gabion to reduce the risk of damage to the tank wall. An effective computer model of thermal air pollution at an industrial site in the event of a fire at an oil storage facility is presented. Practical value. On the basis of the constructed mathematical model, a computer code was created to conduct a computational experiment to determine the effectiveness of using protective barriers (gabions) on the territory of an industrial site.
Experimental Study of Dust Emission Intensity from the Surface of the Alluvium Beach
(IOP Publishing, 2024) Medvedieva, Olha O. ; Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Mormul, Taras; Buketov, Valentyn
ENG: The paper presents data on the current state of waste storage facilities of mining and processing plants in Kryvyi Rih. They are complex, environmentally hazardous hydraulic structures. When assessing the extent of dust pollution from tailing ponds, it is extremely important to know the intensity of dust emissions from the surface of the alluvium beach. This parameter is the basic one in all prognostic models used to predict environmental pollution. The paper presents the results of experimental studies to determine the wind speed at which the removal of dry dust particles from the surface of the beach of a tailing pond begins, as well as the intensity of dust removal from the surface of the beach for dry sand and wet sand. The experimental studies conducted in the laboratory allowed obtaining data on the intensity of dust emission from the surface of the tailing dump beach. The results obtained by the authors make it possible to more accurately assess the degree of environmental dustiness using predictive models. Тhe data on determining the intensity of dust formation for sand of different moisture content will be useful for determining the effectiveness of dust suppression by supplying water to the beach surface.
Experimental Study of the Intensity of Coal Dust Removal
(Prydniprovs'ka State Academy of Civil Engineering and Architecture, Dnipro, Ukraine, 2023) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Brazaluk, Yuliia V.; Kozachyna, Vitalii A.; Oladipo, Mutiu Olatoye
ENG: Problem statement. Industrial sites where coal storages are located are intensive sources of dust pollution of the environment. There is an important problem of assessing the intensity of dust removal into the atmospheric air from polluted areas. Knowledge of the intensity of dust removal into the atmospheric air makes it possible to scientifically assess the impact of contaminated sites on the pollution of the environment and work zones at industrial sites. The solution to this problem can be obtained experimentally. The purpose of the article. An experimental study of the value of the air flow velocity at which the detachment of dust particles from the surface with coal begins and their removal into the air and the determination of the intensity of the emission of coal dust from the contaminated surface. Methodology. The intensity of removal of coal dust from the contaminated area was studied experimentally in laboratory conditions. The research was conducted on coal samples from DTEK “Pavlohradvuhillya”, grade “ДГ. During the research, the velocity of the air flow at which the process of movement of dust particles along the emission source began and the velocity of “detachment” of dust particles and their removal from the emission source were determined. At the second stage of experimental research, the intensity of removal of coal dust from the polluted area was determined. Scientific novelty. The values of the air velocity at which the removal of coal dust particles from the contaminated area begins were determined experimentally. The regularity of the intensity of the removal of coal dust depending on the velocity of the air flow over the contaminated area was obtained. Practical significance. The obtained experimental data make it possible to determine under which weather conditions there is a risk of dust formation and the removal of dust into the atmosphere. The empirical dependence obtained by processing experimental data can be used for a scientifically based assessment of the level of pollution of working areas at industrial sites where there are coal storage facilities. Conclusions. The value of the velocity of the air flow at which the movement of dust particles on the contaminated surface begins, as well as the value of the velocity of the air flow at which the removal of dust particles into the air begins, was determined experimentally. The resulting empirical model can be used to estimate environmental damage due to dust pollution of atmospheric air.
Forecasting Zones of Air Pollution from Solid Waste Landfills
(Український державний університет науки і технологій, Дніпро, 2025) Medvedieva, Olha O.; Dziuba, Serhii V.; Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Kirichenko, Pavlo S.
ENG: Purpose. The work is aimed at developing a mathematical model that allows to quickly calculate the area of chemical air pollution during the emission of hazardous substances from solid waste landfills. The mathematical model takes into account meteorological parameters, geometric shape of the landfill, intensity of emission of hazardous substances from the landfill. Methodology. The two-dimensional equation of convective diffusion transfer of a conservative impurity from the atmosphere is used to analyze the intensity and size of chemical air pollution during the emission of hazardous substances from the landfill. A difference scheme of splitting is used to numerically solve the equation of convective-diffusive transfer of an impurity. The emission of hazardous substances from the landfill is modeled using the Dirac delta function. Findings. The developed mathematical model takes into account the main physical factors that affect the process of dispersion of hazardous substances from the landfill. On the basis of the developed numerical model, a computational experiment was conducted to assess the impact of the landfill on the environment. Originality. On the basis of the developed numerical model, a computer code was developed that allows predicting chemical pollution of the atmospheric wind and the underlying surface in the event of emission of hazardous substances from the surface of a solid waste landfill. The developed model and computer code make it possible to quickly assess the extent and intensity of environmental pollution from landfills, which is important when selecting sites for new or reconstructed landfills. Practical value. The software implementation of the developed numerical model was carried out, and a computational experiment was conducted to illustrate the effectiveness of using the model to solve applied problems related to the impact of landfills on the environment. The results of the numerical experiment are presented.
Hazard Modelling of Accidental Event in Urban Environment
(IOP Publishing Ltd, 2025) Biliaiev, Mykola M.; Kalashnikov, Ivan V.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia V.
ENG: This paper investigates the impact of accidental event at the gas station which is situated in Dnipro City. The processes of chemical and thermal air pollution were simulated on the basis of developed numerical models. To simulate chemical and thermal air pollution mass conversation equation and energy equation were used. For the numerical integration of governing equations finite difference schemes of splitting were used. Also, the process of fragments scattering which appears as the result of explosion at the gas station was modelled. To simulate fragments scattering Newton second Law was used. To solve the governing equation Euler’s method was used. Results of numerical experiments are presented.
Heat Capacity of Thin Films at High Temperatures
(Інститут металофізики ім. Г. В. Курдюмова НАН України, Київ, 2023) Shtapenko, Eduard Ph. ; Syrovatko, Yuliya V.
ENG: The purpose of this paper is to develop a model, which allows determining the heat capacity of thin films at the temperatures comparable to and exceeding the Debye temperature. The model presented in the paper takes into consideration the anisotropy of vibrations of the corresponding bending waves and wave vibrations in the plane occurring with the decrease in the film thickness. Furthermore, the model is based on the quadratic dispersion law for bending wave vibrations in the normal direction of a thin film and the linear dispersion law for the wave vibrations in the film plane. In order to expand the existing model representations for the heat capacity of thin films at low temperatures, we used the Debye’s method in the integral expression for the free energy. We considered this approach earlier in the model representations of the heat capacity of anisotropic quasi-crystals. Our findings show that the thin-film heat-capacity dependence on the temperature has a maximum and exceeds the heat capacity of a bulk sample. This circumstance confirms the experimental data obtained earlier by other authors. Besides, according to the experimental data collected from the literature, heat capacity of the thin films rises, compared to values of the bulk sample, when the film thickness decreases. This factor is also reflected in the model under consideration, and the calculated dependence of the increase in thin films on the number of atomic layers correlates well with the experimental data. Therefore, the proposed model allows determining the heat capacity of thin films at the temperatures exceeding the Debye temperature with sufficient accuracy without experimental investigation.
Identifying Regularities in the Propagation of Air Ions in Rooms with Artificial Air Ionization
(PC TECHNOLOGY CENTER, 2023) Levchenko, Larysa; Burdeina, Nataliia; Glyva, Valentyn; Kasatkina, Natalia; Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Tykhenko, Oksana; Petrunok, Tetiana; Biruk, Yana; Bogatov, Oleg
ENG: The object of the study is the dynamics of air ion spread in rooms from the source of artificial air ionization under different starting conditions. There is currently the problem of distribution of air ions in the room with regulatory concentrations in all critical zones. An effective method of ensuring proper air ion concentrations is to model their propagation from ionization sources. Existing approaches to calculating the dynamics of air ions of both polarities have been improved in this study. Unlike known solutions, the impact on their concentration of electrostatic field and the interaction of air ions with suspended particles was taken into account. A model of air ion propagation in rooms with artificial air ionization and the principles of its numerical modeling was built. The use of Laplace Equation in the aerodynamic model instead of the Navier-Stokes equation for the potential of the flow rate has made it possible to design an "Ion 3D" tool, which reduces the time of implementation of one scenario from several hours to 7 seconds. Modeling of the propagation of air ions of both polarities in the room under different initial conditions was carried out. Two-dimensional and three-dimensional models with their visualization was implemented. The peculiarity of the resulting models is that they make it possible to determine the concentrations of air ions in any section of the room by three coordinates. Given this, the rapid selection of the variants of the source data makes it possible to achieve the normative values of concentrations of air ions in the area of breathing – exceeding 500 cm-3 of each polarity. Simulation makes it possible to design a room in which, under the condition of artificial ionization of air, the concentrations of air ions close to the optimal values of 3000–5000 cm-3 are provided.
Kinetic Regularities of the Formation of Composite Electrolytic Coatings Containing Ultradispersed Diamond Particles
(Vasyl Stefanyk Precarpathian National University, Ukraine, 2022) Tytarenko, Valentyna V.; Zabludovsky, Vladimir A.; Shtapenko, Eduard Ph.; Tytarenko, Igor V.
ENG: The paper formulates the problem of joint electrolytic co-deposition of metal ions and ultradispersed diamond particles into a metal matrix. It presents the developed mathematical model that describes the mechanism and kinetics of the cathode process, mass transfer of metal ions and ultradispersed diamond particles. A satisfactory correlation with experimental data was obtained. The contribution of the thermal action of laser radiation to the intensification of the process of co-deposition of dispersed particles and metal ions was determined. It was found that the more intense penetration of dispersed phase particles into the forming coating during the laser stimulation of the electrodeposition process is due to the presence of a temperature gradient, which provides an additional supply of metal ions in the irradiation region. Based on the theoretical and experimental studies, we established the regularities of the influence of the number and size of nanoparticles on the strengthening properties of composite metal coatings. It was found that an increase in the temperature of an aqueous electrolyte solution in the cathode region during a laser-stimulated deposition process leads to an increase in the flux density of ultradispersed diamond particles, and, as a result, to an increase in the concentration of the dispersed phase in nickel composite coatings, which contributes to the formation of a finer crystalline structure of coatings, an improvement in adhesion, strength properties and increased wear resistance of coatings.
Laser-Assisted Electrodeposition of Composite Carbon-Containing Nickel Coatings
(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, Kyiv, 2024) Tytarenko, Valentyna V.; Zabludovsky, Vladimir A.; Tytarenko, Igor V.
ENG: The paper presents the study of the structure, protective and mechanical properties of nickel composite coatings modified with ultradispersed diamonds and electrodeposited under conditions of external stimulation by laser radiation. An analysis of the cathodic polarization curves shows that the presence of dispersed particles with a concentration of 2-15 g/l in the aqueous electrolyte solution leads to a shift in the cathodic potential to the electronegative region by 108-340 mV, respectively, that indicates an increase in charge-transfer resistance. Nickel composite coatings obtained by laser-assisted electrodeposition are characterized by a higher content of ultradispersed diamond particles in the coating (4.35-5.10 wt.%) as compared to the mode of deposition without laser irradiation (2.24-3.15 wt.%). In this case, the proportion of particles of smaller size (~0.25-1 µm) increases in the coatings. The more intense penetration of dispersed-phase particles into the emerging coating during the laser stimulation of the electrodeposition process is due to the presence of a temperature gradient, which provides an additional supply of metal ions in the irradiation region. Increased concentration of the dispersed phase in nickel composite coatings promotes formation of a finer crystalline coating structure, enhanced hardness, corrosion resistance, and wear resistance of the coatings.
Mathematical Modeling of Filtration and Geomigration Under Conditions of Anthropogenic Load
(Український державний університет науки і технологій, Дніпро, 2025) Bubnova, Olena A.; Miroshnik, Vitaliy A.; Markul, Ruslan V.; Mashykhina, Polina B.; Tatarko, Larysa H.
ENG: Purpose. The aim of this study is to develop mathematical models for predicting the processes of contamination of the aeration zone and groundwater in the event of leachate leakage from a solid waste landfill. The mathematical models take into account typical hydrological parameters: porosity of the aeration zone, aquifer, filtration coefficient of the aeration zone, filtration coefficient of the underground aquifer, intensity of leachate infiltration into the aeration zone and underground aquifer. Methodology. A one-dimensional filtration equation and a one-dimensional mass transfer equation were used to model the process of infiltrate migration in the aeration zone. The modeling of the process of contamination of the underground aquifer, which receives infiltrate from the landfill, was carried out on the basis of a two-dimensional equation (planned model) of geomigration. For the numerical integration of the model equations, a variable-triangular finite-difference splitting scheme was used. The numerical integration of the two-dimensional geomigration equation is performed using the splitting scheme. The peculiarity of the proposed numerical models is that the value of the unknown function can be determined by an explicit formula. Findings. Numerical models have been developed to solve the complex problem of predicting the contamination of the aeration zone and underground flow in the case of infiltration of an impurity from a solid waste landfill. Originality. Numerical models of filtration and mass transfer of impurities in the case of migration of infiltrate from a municipal solid waste landfill through the aeration zone and into groundwater are proposed. To apply these mathematical models, standard hydrological information is required. The models are aimed at solving complex problems in the field of environmental safety and protection. They make it possible to determine the negative impact of landfills on the environment at the stage of justifying the location of future landfills and their size. Practical value. The proposed mathematical models use standard hydrological information, which is important for serial calculations in design organizations, and can be useful for assessing the impact of landfills on environmental pollution.
Mathematical Modeling of Heat and Mass Transfer Processes in Safety Labour Problems : Dust and Heat Pollution
(Prydniprovs’ka State Academy of Civil Engineering and Architecture, USUST, Dnipro, 2025) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Kirichenko, Pavlo S.; Kozachyna, Vitalii A.; Tymoshenko, L. O.
ENG: Problem statement. The operation of many industries is associated with dust and thermal air pollution. Particularly intense dust pollution of the air occurs during the operation of the mining complex. Intense thermal air pollution occurs during fires. Fires are a dangerous phenomenon at industrial and civil facilities. If a fire occurs at an industrial facility where oil storage facilities are located, a very intensive area of thermal pollution of the atmospheric air arises. This creates a risk of thermal injury to workers and a risk of ignition of oil storage facilities located near the source of ignition. An important practical task arises − reducing the risk of ignition of neighboring storage facilities. One of the means of reducing the risk of ignition is the use of protective screens, gabions at industrial sites. For practice, it is important to determine in advance the stability of such structures under the influence of a heat wave and to assess the "contribution" of these structures to reducing the air temperature near neighboring oil storage facilities. Reducing the air temperature near neighboring storage facilities increases the stability of bulk structures. Solving this class of problems requires the use of specialized mathematical models of aerodynamics and heat transfer. The purpose of the article. Creation of a CFD model for assessing thermal fields at an industrial site in the event of a fire and development of numerical models for predicting dust pollution of the air environment. Methodology. To simulate thermal fields at an industrial site, a potential flow and heat transfer model is used. To simulate the heating of a protective structure (shield), a one-dimensional heat conduction equation is used. Numerical integration of the modeling equations is carried out using explicit schemes. A mass transfer equation is used to model dust air pollution. Scientific novelty. Two numerical models are proposed for a comprehensive solution to the problem of determining the temperature field at an industrial site and inside a protective structure (screen) used to reduce the thermal load on a neighboring oil storage facility. Proposed numerical models for the analysis of dust air pollution. Practical significance. The implementation of the developed numerical models is implemented in real time. With the practical implementation of numerical models, almost all information regarding thermal fields formed on an industrial site during a fire can be obtained. This information allows you to identify areas with an intense increase in temperature, i.e. areas with a significant risk of injury to workers. Conclusions. Effective numerical models are proposed for solving complex problems in the event of a fire at an industrial site and in case of dust emission. The models make it possible to assess the level of thermal pollution of atmospheric air at the site and the effectiveness of using a protective screen to reduce the air temperature near a neighboring storage facility.
Mathematical Models for Water Treatment Problems
(Український державний університет науки і технологій, Дніпро, 2025) Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Kyrychenko, M. V.; Skuratov, M. O.; Chirkov, A. O.; Filonenko, H. K.
ENG: Purpose. Assessing the efficiency of water treatment in different structures is a problem of big importance. To solve this a problem, it is necessary to have mathematical models that allow to quickly obtain data on the cleaning effect in different structures. The aim of the work is to develop numerical models to determine the efficiency of water treatment in an aeration tanks, settlers and mixers. Methodology. For mathematical modeling of the process of water treatment in a bioreactor, balance equations were used. These equations allow to determine concentrations of substrate, activated sludge and dissolved oxygen in s structure. The Monod model is used to calculate the substrate oxidation process. To study effectiveness of water treatment process in vertical settler Euler’s equation were used with convective-diffusive equation. To simulate reagent mixing in mixer equation of potential and convective-diffusive equation were used. To solve governing equations finite- difference schemes of splitting were used. Findings. A tool for theoretical assessment mass transfer processes in aeration tank, vertical settler, mixer was developed. Originality. Effective numerical models to simulate water treatment in bioreactor, vertical settler, mixer were developed. Fundamental equations of Fluid Dynamics and Mass Transfer were used to build the models. Proposed models can be used in practice at the stage of «sketch designing». The models take into account the main physical parameters which influence the process of Mass Transfer and are quick computing. Practical value. The constructed mathematical model can be useful during the reconstruction and designing structures for water treatment. Computer programs have been developed to carry out numerical experiment. The results of a computer experiment are presented.
Methodology for Modeling the Spread of Radioactive Substances in Case of an Emergency Release at a Nuclear Power Plant
(National Technical University «Kharkiv Polytechnic Institute», Kharkiv, 2023) Levchenko, Larysa; Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Ausheva, Nataliia; Tykhenko, Oksana
ENG: The methodology for modeling the propagation of accidental releases of radionuclides from a power unit of a nuclear power plant has been developed. The calculation method takes into account the most critical factors propagation cloud - wind direction and speed, the intensity of the release radionuclides change: semi-continuous release, long-term release, instantaneous release. Diffuse processes and the presence of interference in the form of buildings were also taken into account. To solve the modeling equation of the aerodynamic model, the velocity potential equation is solved. The use of this equation instead of the traditional Novier-Stokes equation makes it possible to rationalize the calculation process in terms of the speed obtaining simulated data. To build a numerical model, a rectangular difference grid is used. The velocity potential and the quantities values of volumetric activity are determined at the centers of difference cells. The value of the airflow velocity vector component is determined on the sides of the difference cells. A finite-difference splitting scheme is used for numerical integration of the equation convective-diffusion transfer radionuclides. A computer code was developed on the basis of the constructed numerical model, the programming language Fortran was used. The approach used makes it possible to reduce the time for obtaining one scenario of an accident development. The cloud propagation dynamics determining is carried out almost in real time. This allows you to quickly respond to changing situations and make adequate decisions.
Modeling Ground Waters Dynamics and Pollution
(Prydniprovs'ka State Academy of Civil Engineering and Architecture, Dnipro, Ukraine, 2024) Biliaiev, Mykola M.; Kozachyna, Valeriia V.
ENG: Problem statement. Large accumulators of liquid waste (e.g., mine water ponds, tailing ponds, etc.) are long-term sources that change the hydrological regime. A negative consequence of this process is flooding of the territory. In addition, the infiltration of contaminated water from such hazardous sources changes the quality of groundwater. Therefore, it is important to analyze the impact of such anthropogenic sources on the process of flooding and deterioration of groundwater quality. To solve this problem, it is very important to use the method of mathematical modeling as an effective mean of researching problems of this class, since the use of physical modeling is practically impossible within the scope of problems of this class. The purpose of the article. Development of numerical models for predicting changes in the hydrological regime (flooding of the territory) and groundwater quality under the influence of anthropogenic pollution sources. Methodology. To assess the dynamics of changes in the hydrological regime, a two-dimensional equation of filtration of a non-pressure groundwater flow is used. A two-dimensional geomigration equation (planned model) is used to analyze changes in groundwater quality during infiltration of contaminated water from the settling pond. This equation takes into account the convective transfer of contaminants in the filtration flow, dispersion, and the intensity of contaminant infiltration into the groundwater flow. The method of total approximation is used for numerical integration of the filtration equation. For the numerical integration of the geomigration equation, an implicit splitting scheme is used. Scientific novelty. Effective numerical models for rapid assessment of changes in groundwater dynamics and quality under the influence of anthropogenic sources that change the hydrological regime are proposed. The constructed numerical models take into account a set of important physical factors that affect the process of geomigration and flooding of the territory, namely: filtration coefficient, variable depth of free-flowing groundwater, dispersion, intensity of the source of impurity emission into the groundwater flow. This makes it possible to obtain a comprehensive assessment of the process of flooding and groundwater pollution.. Practical significance. A computer code has been created that allows practical usage of the developed numerical models. This code is an effective tool for theoretical study of non-stationary processes of territory flooding and anthropogenic groundwater pollution. Conclusions. A numerical model for calculating groundwater dynamics has been developed. The model allows to predict the level of groundwater rise under the influence of a man-made source of wastewater infiltration from a settling pond. A numerical model for calculating the process of geomigration from an anthropogenic source of emissions has been developed. The model makes it possible to predict the dynamics of contamination zone formation in a non-pressure groundwater flow. The developed numerical models take into account the most important parameters that affect the formation of flooding zones and groundwater contamination.
Modeling Influence of TiO2 Barrier Coating on Pollutant Dispersion Near Road
(Kaunas University of Technology, 2023) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia; Yakubovska, Zinaida M.
ENG: Mitigation strategies for near-road air pollution are of great interest nowadays. Sound barriers near the road are very effective to decrease pollutant concentration. The use of titanium dioxide (TiO2) barrier coating provides additional effect which allows to decrease pollutant concentration near road. In this study quick- computing CFD model was developed to access influence of TiO2 barrier coating on pollutant concentration. To simulate wind flow over barrier with TiO2 coating model of potential flow was used. The process of NOx dispersion from car was computed using mass conservation equation. Finite-difference schemes were used for numerical integration of governing equations. The computer code was developed on the basis of proposed numerical model. Results of numerical simulations are presented.
Modeling of Filtration and Geomigration Under Anthropogenic Impact on Groundwater
(Ukrainian State University of Science and Technologies, Dnipro, 2025) Medvedieva, Olha O.; Dziuba, Serhii V.; Tiutkin, Oleksii L.; Mashykhina, Polina B.; Berlov, Oleksandr V.
ENG: Purpose. One of the most widespread methods of liquid waste disposal is the use of settling ponds. Wastewater in such lagoons eventually infiltrates into the aeration zone and reaches groundwater. Thus, a chemical contamination area is formed both in the aeration zone and in groundwater. When reengineering sedimentation ponds (for example, when increasing the height of the dam), there is an increase in the pressure in the structure, which will affect the intensity of infiltration of wastewater from the pond into the aeration zone), it is necessary to determine the change in the intensity of environmental pollution in advance. To solve such a forecasting problem, it is necessary to use specialized mathematical models. The aim of the study is to develop numerical models for assessing the dynamics of aeration zone pollution during the infiltration of liquid waste from a sedimentation pond. Methodology. The Laplace equation for the head is used to solve the filtration problem. The process of mass transfer of impurities in the aeration zone is modeled using the mass transfer equation, which takes into account the convective-dispersive transfer of impurities. The numerical integration of the modeling equations is carried out using finite-difference schemes. Findings. Numerical models of filtration and mass transfer are considered, which allow to estimate the dynamics of changes in the contamination area in the aeration zone during the infiltration of liquid wastewater from a sedimentation pond. Originality. The construction of mathematical models for analyzing the infiltration of liquid wastewater from a sedimentation pond is considered. Numerical models take into account the convective-dispersion process of impurity propagation in the aeration area. Practical value. The considered numerical models can be used to assess the environmental impact of sedimentation ponds used for the accumulation of liquid waste.
Modeling the Distribution of Emergency Release Products at a Nuclear Power Plant Unit
(Національний технічний університет "Харківський політехнічний інститут", 2024) Biliaieva, Viktoriia V.; Levchenko, Larysa; Myshchenko, Iryna; Tykhenko, Oksana; Kozachyna, Vitalii A.
ENG: Despite the fact that much attention is paid to the safe operation of nuclear power plants, there is a possibility of an accident with the release of radionuclides. This is especially true in Ukraine, where there is a threat of the damage to nuclear reactors as a result of military operations. It is impossible to research the distribution of products emergency releases radioactive substances in laboratory conditions. Therefore, the only tool for the development predicting of an accident is the modeling the spread of a radionuclides cloud. The purpose of the research is a modeling the distribution of emergency release products in a nuclear power plant unit, suitable for the operative assessment of a development an accident. Results of the research: The mathematical model of the distribution emission products of a nuclear power plant has been developed, which takes into account the value of the initial activity of emission products, the rate of the settling radioactive particles, the wind speed components, the intensity changes radionuclide emission over time. The technique for solving the boundary value problem of modeling in conditions of a complex shape of the computational domain, taking into account the presence of obstacles to the spread of emission products has been developed. The use of the velocity potential equation in evolutionary form allows us to speed up the calculation process. The chosen splitting scheme of an alternating-triangular method allows to find the speed potential according to the explicit form at each splitting step. This allowed software implementation of the CFD model. The visualized models of the emission cloud distribution allow to determine the radiation situation in any place of the emission product distribution zone. The developed model makes it possible to quickly predict the development of an accident in space and time, which makes it possible to take measures to protect people from exposure in the shortest possible time. Conclusions: The obtained emission cloud propagation models and their visualization make it possible to determine the state of environmental pollution under various initial conditions during the development of the accident.
Modeling the Dynamics of Groundwater in Applied Problems
(ESI “Prydniprovska State Academy of Civil Engineering and Architecture”, USUST, Dnipro, 2025) Tiutkin, Oleksii L.; Bubnova, Olena A.; Markul, Ruslan V.; Miroshnyk, Vitalii A.; Mashykhina, Polina B.
ENG: Problem statement. Forecasting and analyzing groundwater dynamics under anthropogenic impact on aquifers is a pressing issue. This task arises when designing drainage systems for flooded areas, designing water intakes from underground sources, the impact of waste disposal sites on the movement of groundwater, and water leakage from water supply and sewage systems. Anthropogenic impact can affect both groundwater (unconfined aquifers) and confined aquifers. Technogenic impact can occur through a system of wells, leakage of effluents from landfills, infiltration of precipitation, and irrational irrigation. Solving this type of problem requires the use of multifactorial filtration models. The purpose of the article. To conduct a comprehensive analysis of mathematical models in groundwater dynamics problems and to identify their advantages and disadvantages. Conclusions. The analysis showed that the modern approach to solving groundwater dynamics problems is to use multidimensional filtration equations that take into account changes in the groundwater level (or hydrodynamic pressure in the confined aquifer) over time. These modeling equations take into account water infiltration into underground horizons. The boundary conditions of the modeling filtration equations that ensure the correct formulation of the boundary problem are considered. It is shown that the formulation of specific groundwater dynamics problems (drainage, operation of water intake wells, etc.) is implemented in models by setting “internal” boundary conditions. Applied problems are analyzed where models of unconfined and confined groundwater flow can be used.
Numerical Analysis of Aerodynamic Regime Near Tailings Storage Facility
(IOP Publishing Ltd, 2023) Semenenko, Yevhen; Medvedieva, Olha O.; Biliaiev, Mykola M.; Rusakova, Tetiana I.; Blyuss, Konstantin
ENG: Tailings formed during the mining and beneficiation of iron ore are sources of intensive dust generation. In order to assess the intensity of dust formation and determine the effectiveness of methods of its reduction, it is necessary to know the local velocity of the air flow near the various surfaces of the tailings storage facility. For the theoretical solution of this problem, a CFD model was developed, which allows determining the velocity field of the air flow when flowing around the tailings storage facility. The model allows you to obtain the value of the wind speed near the surfaces of the structure and, based on this information, to make a forecast of possible dust formation. The constructed CFD model is based on the use of an aerodynamic model of potential motion. The modeling equation is the Laplace equation for the velocity potential. To build a numerical model, the idea of establishing a solution in time is used, therefore numerical integration of the "unsteady equation" for the velocity potential is carried out. Numerical integration is carried out using the finite-difference method of total approximation. The results of the computational experiment are presented.
Numerical Modeling of Groundwater Dynamics and Heat and Mass Transfer Processes
(Pridneprovs’ka State Akademy of Civil Engineering and Architecture, USUST, Dnipro, Ukraine, 2024) Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Kirichenko, Pavlo S.; Kozachyna, Valeriia V.; Kaidash, M. D.
ENG: Problem statement. Groundwater is undergoing significant anthropogenic impact in many countries around the world. This impact results in changes in groundwater levels and deterioration of their quality. Protecting groundwater from anthropogenic impact involves solving several important tasks. A significant number of tasks are related to the need to predict the processes of filtration and heat and mass transfer in underground flows. In this regard, it is important to have specialized mathematical models as a modern scientific research tool. It should be noted that the use of physical experiments for problems of this class is significantly limited, due to the high cost of equipment, considerable time spent on setting up and conducting the experiment. The purpose of the article. Development of a set of numerical models for simulation of filtration and heat and mass transfer processes in groundwater. Methodology. To model the process of non-pressure flow of groundwater, the equation of non-pressure filtration is used. The two-dimensional equation of convective-diffusive movement of a pollutant is used to model the process of mass transfer of an impurity in groundwater. To model the process of heat transfer in groundwater, in the problem of groundwater freezing, a two-dimensional energy equation is used. For numerical integration of modeling equations, finite-difference schemes are used. Scientific novelty. Numerical models of filtration and heat and mass transfer processes have been developed that allow real-time analysis of changes in groundwater quality and thermal regime. Practical significance. The developed numerical models make it possible to quickly analyze non-stationary processes of heat and mass transfer in groundwater when developing drainage systems in flooded areas. Conclusions. Numerical models of filtration and heat and mass transfer in groundwater have been developed. For the practical use of the built models, standard hydrological information is required. The models make it possible to analyze the dynamics of ice formation in groundwater during the implementation of the technology of freezing groundwater flow.
Numerical Modeling of the Wind Regime on the Beaches of the Wash of the Artificial Storage Facilities for Mineral Processing Waste
(IOP Publishing, 2024) Lapshyn, Yevhen; Biliaiev, Mykola M. ; Biliaieva, Viktoriia V. ; Halchenko, Zariana; Medianyk, Volodymyr; Buketov, Valentyn
ENG: A 2D numerical model has been developed to estimate the airflow velocity field when flowing around the dam of an artificial storage facility for mineral processing waste. To solve the aerodynamic problem of determining the air flow velocity field when flowing around such hydraulic structures with a complex geometric shape, a potential motion model was applied. The numerical integration of the equation for the velocity potential is carried out using the Liebman method. The geometric shape of the tailings storage facility is formed in a discrete model using the marking method. A computer program was created to implement the developed numerical aerodynamics model. Based on the processing of the results of computational experiments, coefficients were obtained that allow us to quickly determine the value of the air flow velocity at the beginning and end of the tailing pond beach, i.e. in the area of the most intense dust emission. This allows for a quick prediction of the risk of dust air pollution at different tailing pile heights.
Numerical Simulation of Pollutant Dispersion from Road with Barrier
(IOP Publishing Ltd, 2025) Biliaiev, Mykola M.; Kalashnikov, Ivan V.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia V.
ENG: The impact of protective barriers on air pollution dispersion near the road was examined using developed numerical model. To simulate wind flow over barrier model of potential flow was used. To simulate pollutant dispersion from road convective-diffusive equation was used. Difference schemes of splitting were used for numerical integration of governing equations. Dispersion of pollutant was modeled for scenarios with no barrier near the road, vertical solid barrier, vertical barriers with additional elements, combination “vertical barrier and plate on the pavilion”. To estimate the efficiency of each scenario potential hazard risk indicator was used. Results of numerical experiment are presented.
Photoinduced Effects in Single Crystals of PbO-MoO3 System
(Institute of Physics PAS, Poland, 2022) Bochkova, Tatiana; Bondar, Dmytro; Trubitsyn, Mykhailo P.; Volnianskii, M. D.; Volnyanskii, Dmytro M.
ENG: Purpose. Photoinduced changes in the optical absorption and dielectric properties of PbMoO4 and Pb2MoO5 crystals are considered. Differences in the manifestation of the photochromic effect in both crystals are associated with differences in their crystal structure. It is assumed that the photodielectric effect in the PbMoO4 and Pb2MoO5 crystals is due to the presence of the same anionic complexes. Methodology. Single crystals of PbMoO4 and Pb2MoO5 were grown in air from melt by the Czochralskii method. High-temperature treatment of the PbMoO4 crystals in air was carried out in a muffle furnace at 1200 K. The annealing time in the experiments varied from 2 to 90 h. Annealing of Pb2MoO5 crystals in vacuum was carried out at 1000 K during 1–2 h. The optical transmission spectra were measured at 295 K on the crystal doubly polished plates using a “Specord M-40” spectrophotometer. The photochromic coloration was observed after irradiation by light of Hg lamp during 2–5 h. Colored samples were returned to the initial state by annealing at 700–800 K in air for 2 h. Permittivity " was measured in the AC field by the four-wire method using a Keysight E4980AL LCR Meter at different frequencies (f = 1–10 kHz) in the temperature interval 290–700 K. Findings. One can assume that the photodielectric effect has the same nature and can be attributed for the common for both PbMoO4 and Pb2MoO5 crystals coordination complexes, i.e., molybdenum–oxygen tetrahedra. The dipole defects contributed to the photodielectric effect can be associated with Mo–O tetrahedra distorted by oxygen vacancy and photoelectrons capture. Hopping of VO through Mo–O tetrahedra vertices is accompanied by re-orientations of dipole moments of (MoO3)- complexes. Originality. Photoinduced changes in optical absorption and dielectric properties of PbMoO4 and Pb2MoO5 crystals are considered. The model of the mechanism of such changes of the power is offered. Practical value. The obtained conclusions will help to predict the influence of the composition of single crystals of acousto-optical materials of this series on their properties of practical value - optical absorption, optical stability..
Prediction of Atmospheric Air Pollution Near a Coal Stack in Adverse Weather Conditions
(IOP Publishing Ltd, 2023) Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Nochvai, Volodymyr; Yakubovska, Zinaida M.; Oladipo, Mutiu Olatoye
ENG: Coal piles on the territory of enterprises are long-term sources of dust pollution of atmospheric air. Forecasting the level of dust pollution of the air for such objects is carried out, as a rule, for convection conditions. But during inversion, very high concentrations of dust can occur on industrial sites. The task of assessing the level of dust pollution of atmospheric air at an industrial site during dust emission in conditions of inversion from a coal stack is considered. A three-dimensional equation of convective-diffusion dispersion of contamination in atmospheric air, compatible with the approach of Prof. Berliand M. on determining the value of the vertical diffusion coefficient in the surface layer of the atmosphere for the case of inversion, to model dispersion of dust from a coal stack under inversion conditions is used. Numerical integration of the modeling equation of convective-diffusion transport of contamination is carried out on the basis of the splitting method compatible with the use of a locally one-dimensional finite-difference scheme. The results of a computational experiment to determine dust pollution zones at the Prydniprovsk thermal power station are presented.
Quantum-Mechanical Methodology for Determining the Temperature Dependence of Contact Angle in Melt–Solid Metal Systems
(Oles Honchar Dnipro National University, Dnipro, 2024) Shtapenko, Eduard Ph.; Syrovatko, Yuliya V.; Voronkov, Eugene O. ; Mikhailova, Tetiana F.
ENG: Aim. In order to determine the composite materials’ manufacturing process parameters, it is necessary to evaluate the stability of their structural components and determine the contact angle of wetting of the filler with the molten binder at the infiltration temperature. The development of a theoretical method for determining the dependence of the contact angle of wetting on temperature in melt – solid metal systems makes it possible to reduce the volume of experimental studies. Methods. The paper presents a quantum mechanical methodology for calculating the binding energy of interacting substances, as well as an experimental study of the dependence of the contact angle on temperature for tin – steel systems. The methodology is based on the calculation of the binding energy between atoms of interacting substances using density functional theory. Results. The calculations show an anomalous behavior of contact angle values for the tin–steel system with increasing temperatures. It means that, when the temperature increases, the values of the contact angle initially become lower, and later, in the temperature range of 450-510 °C, an increase in the contact angle is observed. The obtained theoretical and experimental data correlate well with each other. Conclusions. The appearance of extreme regions in the experimental and theoretical temperature dependences is associated with the thermal expansion of interatomic distances in the crystal lattice. The obtained theoretical and experimental data correlate well with each other and base on the thermal expansion of interatomic distances in the crystal lattice.
Quick computing CFD model to predict chemical pollution in room
(Український державний університет науки і технологій, Дніпро, 2024) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Mashykhina, Polina B.
ENG: Purpose. The problem of accidental contamination of workspaces attracts special attention, since in the event of such extreme situations, intense chemical contamination of the air in work areas occurs. This poses a threat of toxic exposure to workers. When assessing the consequences of such situations, it is necessary to take into account the time factor, in particular, to quickly determine the creation of concentrations of chemically hazardous substances. In this regard, an urgent task is to develop effective mathematical models for rapid assessment of the consequences of extreme situations in the working areas of chemically hazardous facilities. The paper considers a CFD model for analyzing the process of chemical air pollution in a workspace during an accidental release of a chemically hazardous substance. The solution of the problem is based on the numerical integration of the fundamental equations of continuum mechanics. Methodology. To calculate the air velocity field in the working room during the operation of supply and exhaust ventilation, a mathematical model of the motion of an inviscid fluid was used. The equation of convective diffusion motion was used to calculate the concentration of a chemically hazardous substance in the workspace. The integration of the modeling equations was carried out using finite difference schemes. Findings. A dynamic model has been created to calculate the spread of a chemically hazardous substance in a work-space. On the basis of the built CFD model, a computer program was created to conduct a computational experiment. Originality. A CFD model has been created to predict the level of air pollution in a workspace in the event of toxic gas emissions. The model is based on the fundamental equations of aerodynamic mechanics and mass transfer. The model makes it possible to determine the effect of the ventilation mode, the intensity of emission of a chemically hazardous substance, the location of equipment in the workspace, and the dynamics of the formation of concentration fields. Practical value. The developed CFD model can be used to quickly analyze the consequences of accidental emissions of a chemically hazardous substance in a workplace and assess the risk of toxic exposure of workers.
Simulation of Chemical Accident with Ammonia at the Pipe Line
(Kaunas University of Technology, 2023) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia; Mashykhina, Polina B.
ENG: Ammonia is transported through Ukraine via the Togliatti-Odesa ammonia pipeline. The hostilities in Ukraine pose a risk of damage to this transportation system as a result of a shell, mine, etc. hitting the transportation system. Therefore, it is very important to predict the possible consequences of environmental pollution in the event of such an extreme situation. A numerical model was developed to solve this problem. The three-dimensional equation of convective-diffusive transport of an impurity in the atmosphere is used to predict the dynamics of pollution of atmospheric air and the underlying surface. Finite-difference splitting schemes are used to numerically integrate this equation. On the basis of the constructed numerical model, a computer code was developed to take into account the change in the intensity of ammonia leakage from the damaged pipeline. The results of a computational experiment are presented.
Simulation of the Formation of Protective Coatings using the Radial Distribution Function of Atoms
(Dnipro State Technical University, Kamianske, Ukraine, 2023) Sereda, Borys; Baskevich, Oleksandr; Gulivets, Alexey; Udod, Andrey
ENG: Studies of the structural factors of alloys, carried out using wide-angle and small-angle X-ray studies, allowed us to identify general patterns for various alloys. The use of apodization of the Fourier distribution of X-ray diffraction (XRD) contributes to the leveling of the effect of the break in the experimental intensity curve and facilitates close-order modeling. It was established that the height of the main peak of the structural factor decreases, and the position slightly shifts towards larger angles when the arrangement of alloys increases. The second maxima of the structural factor have an asymmetric shape, which varies depending on the conditions for obtaining the alloys. As the amount of phosphorus in the alloys decreases, the relief and height of the peaks increase. It was found that the diversity of the close order of the alloys is related to the deposition conditions, in particular, to a large value of the overvoltage at the cathode and the penetration of phosphorus atoms into the structure of the alloys. The obtained modeling results allow us to establish the conditions for the formation of close order in alloys and expand our understanding of the structural features of materials.
Simulation of the Structure of Chromium Carbide in the Research of Amorphous Alloys
(Dnipro State Technical University, Kamianske, Ukraine, 2023) Kruglyak, Irina; Baskevich, Oleksandr; Gulivets, Alexey; Maksimenko, Oleg
ENG: Work are considered theoretical aspects of modeling amorphous and nanocrystalline alloys of transition metals and metalloids. Modeling of the close order of amorphous Cr–C alloys obtained by the electrodeposition method was carried out, depending on the current density and temperature of the electrolyte. The dependence between the production conditions and the close order of amorphous alloys was established. A technique for deciphering the radial distribution function of atoms (RDF) based on the concept of the cluster structure of amorphous metals has been developed. Modeling of the close order of amorphous Cr–C alloys was carried out using the approximation of the peaks of FRPA atoms, which are characteristic of the amorphous Ni86P14 alloy. The structure of electrodeposited Cr–C precipitates at different values of current density and electrolyte temperatures was investigated. It was established that the structure of the material is amorphous, and the sizes of the oriented random regions (ORA) vary from 3.6 to 5 nm. The lattice parameters of the samples increase slightly, which is associated with a change in the amount of carbon. The volume of the sediment consists of ORA, the shape of which is close to cuboctahedra, and the volume fraction decreases with an increase in the temperature of the electrolyte.
Study of the Short-Range Order of Co-W Alloys Electrodeposited Using Pulse Current
(Vasyl Stefanyk Precarpathian National University, 2023) Gerasimenko, Dmitriy; Tytarenko, Valentina V.
ENG: Pulsed electrodeposition modes allowed to obtain amorphous Co-W alloys. Using X-ray phase and spectral analysis methods, it was established that the deposition modes and the concentration of the amorphizing component (sodium tungstate salts) in an aqueous electrolyte solution affect the amorphization of alloys. The short-range atomic order was studied by X-ray diffraction analysis and the sizes of the regions of ordered arrangement of atoms were determined in X-ray amorphous Co-W alloys obtained by pulsed electrodeposition. The radial distribution function of atoms was analysed. The assumption is made that cobalt and tungsten atoms combine into configurations that are irregular polyhedrons.
Адгезійна міцність електроосаджених металевих плівок з металевими підкладками
(Дніпровський національний університет ім. Олеся Гончара, Дніпро, Україна, 2023) Штапенко, Едуард Пилипович; Воронков, Євген Олегович; Заблудовський, Володимир Олександрович; Титаренко, Валентина Василівна; Краєва, Віолетта С.; Кузнецов, Віталій Миколайович
UKR: У роботі розглянуто адгезійну міцність електроосаджених покриттів нікелю, заліза, міді та цинку на мідній та сталевій підкладках. Для визначення теоретичних значень адгезійної міцності запропоновано теоретичний підхід до визначення адгезійної міцності на межі метал-метал. Авторами на основі аналізу механізму адгезії і природи контактної взаємодії отримано аналітичний вираз для розрахунку значень адгезійної міцності для певних пар металів, проте знаходження точного значення ряду величин, що входять у цей вираз, наприклад, питомої енергії зв'язку та модуля пружності, становить великі труднощі. Розрахунок енергії взаємодії атомів покриття та підкладки проводили за методом теорії функціоналу густини. У результаті було отримано теоретичні значення адгезійної міцності електроосаджених покриттів нікелю, заліза, міді та цинку на мідній та сталевій підкладках, які добре узгоджуються з експериментальними значеннями адгезійної міцності. Однак, існуючі розбіжності між теоретичними та експериментальними даними викликані певними труднощами знаходження питомої енергії зв'язку та модуля пружності, які пов'язані зі складністю моделювання реальної структури як плівки, так і підкладки. Пошуки вирішення цих питань стануть предметом подальших досліджень.