Кафедра Гідравліка, водопостачання та фізика (З 2022 року кафедра створена шляхом злиття кафедри Гідравлика та водопостачання та кафедри Фізика)
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Item 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.Item 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, PavloENG: 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.Item 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; Lapshin, Yevhen; Koval, NataliaENG: 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.Item 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.Item 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.Item 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.Item Experimental Study of Dust Emission Intensity from the Surface of the Alluvium Beach(IOP Publishing, 2024) Medvedieva, Olha; Biliaiev, Mykola M.; Kozachyna, Vitalii A.; Mormul, Taras; Buketov, ValentynENG: 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.Item 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 OlatoyeENG: 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.Item 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.Item 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, OlegENG: 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.Item 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.Item 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.Item 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, OksanaENG: 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.Item 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.Item 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.Item 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.Item Numerical Analysis of Aerodynamic Regime Near Tailings Storage Facility(IOP Publishing Ltd, 2023) Semenenko, Yevhen; Medvedieva, Olha; Biliaiev, Mykola M.; Rusakova, Tetiana I.; Blyuss, KonstantinENG: 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.Item 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.Item 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, ValentynENG: 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.Item 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..
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