Direct and inverse problems to study the process of ion solutions ltering in porous medium

Solution of actual problem associated with technological process of ltering and dehydrating liquid solutions from ne-dispersed particles is discussed in the paper. Technological process is carried out in the dehydration and puri cation of chemical solutions, drinking water, pharmaceuticals, liquid fuels, products for public use, etc. A mathematical model has been developed to study the process, to determine the basic parameters of the object and the operating modes of the ltering aggregates to make management decisions; this model may take into account di erent operating modes of the ltering aggregate and physical-chemical properties of solutions. In the paper it is noted that when investigating the ltering process, it is rather di cult to determine the main parameters of the object under consideration and their ranges of changes to control the operating objects. Collecting data takes a lot of time; to conduct a series of experiments in laboratory conditions takes a lot of labor power and time; it is di cult to nd the relationship between the parameters of the lter and technological process based on a limited experimental sampling. Urgent problems of determining the basic parameters and their ranges of changes leading to a decrease in the loss of valuable raw materials, an increase in lters performance, an improvement in the quality of the resulting product, etc. are solved in the paper. Based on the analysis of the conducted numerical experiments, conclusions are drawn that serve as the basis for making appropriate management decisions

The role of radiography and magnetic resonance imaging in diagnosis of slipped capital femoral epiphysis in children and adolescences

Background Slipped capital femoral epiphysis remains a diagnostic problem despite numerous papers written on the subject. Radiographic imaging is important in the confirmation of the diagnosis. Purpose Explore changes in the proximal femur at early clinical manifestations of slipped capital femoral epiphysis (SCFE) to further study patterns and localisation of pathological process. Material and methods The imaging findings from the conventional radiological and magnetic resonance examinations are presented, patterns of displacements and structural abnormalities in the proximal femur described. Results MRI is the most informative imaging modality for detecting SCFE at early stages. Conclusion In our opinion MRI can be used to detect and predict a slip of the femoral hea

MODELING AND ANALYSIS OF NONSTATIONARY GAS FILTRATION UNDER GAS DYNAMIC PARAMETERS VARIATION

A mathematical model that describes a partial differential equation with boundary, internal and initial conditions was developed in the article, to study the gas-dynamic parameters of the gas filtration process in a porous medium under isothermal conditions. The study was performed based on the reviews of research works related to mathematical modeling in recent years. Computational experiments (CE) were conducted on a computer to determine the response of the main parameters on the process of gas filtration in a porous medium on the basis of the developed mathematical tool (model, numerical algorithm, and software). The results of numerical calculations were presented in the form of tables and graphical objects for the purpose of developing oil and gas fields and increasing oil and gas recovery. With the analysis of the numerical calculations performed, it was established that when the parameters and properties of gas filtration are considered as functions of pressure, then the process of gas filtration in porous media can be adequately described, as a whole, and it correctly reflects the main point of the object under research. It could be concluded that with the mathematical tool developed, it became possible to conduct a comprehensive study of the process of gas filtration in a porous medium

Development of models and algorithms of aerodynamic drag of a high-speed train and calculations of particle entrainment

The work is a study of the patterns of jet-cavitation air flows when flowing around a high-speed passenger train. On the basis of theoretical studies, the forces of resistance (frontal and near-wall) of the external environment to the movement of the train, the influence of cavitation currents on the near-wall layer, the current flows generated during the movement of the rolling stock, the resistance of the external environment of the rolling stock, both as a whole and on each car of the train, are determined, the influence of cavitation flow from solid particles lying on the underlying surface, critical velocities that reduce the entrainment of solid particles, establishing the regularity of the movement of entrained solid particles. The work also includes a theoretical determination of the aerodynamic drag coefficient and hydrodynamic pressure forces, normal and shear stresses on the surface of the wall of a train consisting of n cars, a study of the effect of gaps between cars and on the speed characteristics of the train, leading to a change in the acceleration of cars