Articles in "Engineering"

Summary: The electrical resistance of undeformed samples hardened in water gradually increases to 300-400 °C due to the positive temperature coefficient of resistance. The progression of the curve from 400 to 700 °C indicates the development of the K-state. In the temperature range 700- 925 °C, the solid solution decomposes with the formation of particles of a strengthening phase, which leads to a decrease in electrical resistance. The rise of the curve above 950 °C is associated with the dissolution of previously released particles of the second phase. The heating curve indicates the occurrence of the mentioned processes in reverse order. In deformed samples, the formation of the K-state during heating occurs in a wider temperature range (from 100 to 700 °C) and is much more intense than in undeformed samples. The course of the cooling curve is similar to the cooling curve of samples quenched in water [1]. The cooling curve in the temperature range 775-500 °C is slightly higher than the heating curve, which is associated with different degrees of formation of the K-state due to different “initial” structures [2]. After cooling, the electrical resistance of undeformed samples cooled in a furnace returns to its original value. In deformed samples it is 5% higher than before heating, which indicates a stable influence of deformation on subsequent transformations. The magnitude of the change in electrical resistance after cooling depends on the previous treatment. For samples quenched only in water, it is 3.5% higher, for samples with a reduction of 50% - by 8.7%, for samples with a reduction of 75% - by 10.5%. This increase in electrical resistance is determined by the occurrence of the K-state during cooling, and the different magnitude of the increase is associated with the influence of the deformation energy (preserved even after high heating) on the development of the process of formation of the K-state during cooling. An increase in the electrical resistance of samples cooled with the furnace from the quenching temperature is observed only up to 550 0C, regardless of whether the samples were subjected to work hardening or not, and this increase is significantly less than that of the same samples, but quenched in water [1, 3]. When cooling with the furnace from the quenching temperature, some development of the K-state already occurs in the samples, which is probably not completely destroyed even with a reduction of 50%. This determines a smaller increase in electrical resistance during subsequent heating and shifts the maximum to a temperature of 550 °C [2, 5]. In addition, a distinctive feature of the heating curves of the samples is a two-stage drop in electrical resistance in the temperature range of 550-950 °C.

Summary: The presented paper is devoted to the solution of cylindrical free oscillation problems of a rectangular plate, taking into account the resistance of the external environment. In the title of the article, accepting a cylindrical oscillation is not chosen randomly and it is a rare issue in the theory of plates and coatings, therefore, the solution of the considered problem is new and relevant. In this paper, the influence of the external environment is considered viscoelastic according to the Voigt model, the plate is assumed to be rectangular, thin-walled, and orthotropic, being heterogeneous along its length (i.e., in the direction of the large side). The conditions for fixing the contours of the plate are chosen in such a way that a heterogeneous boundary condition is obtained, otherwise the shape of the free oscillation cannot be cylindrical. Under the required conditions, the oscillation equation of the plate is formulated, and as a result, the fourth order partial differential equation with a variable coefficient is obtained. The obtained equation is a complicated enough equation modified from the Sophie-Germain equation written for the deflection of the plates according to the condition of the problem, and it is hard to be solved. Such equations do not have an analytical solution, and for now the most rational method for its solution is considered to be Bunov Galerkin's method of orthogonalization and separation of variables. In order to calculate the value of the frequency of the oscillation, the relationship equations were obtained, the calculations were carried out for cases where the characteristic functions change with a linear law, and the material of the plate is homogeneous and heterogeneous. Equations of dependence between dimensionless frequency and characteristic functions and parameters characterizing a heterogeneous viscoelastic base were obtained. An error function was constructed for the obtained equation and the orthogonalization condition was checked with the help of the error function. In order to compare the solution of the problem, the frequency analysis of the plate was carried out using the finite element method, for which the frequency analysis was carried out in 6 frequency cases on plates with different length dimensions. Solidworks software was used here. The results were presented in form of graphs and tables.

Summary: The test research facility, in which the properties of warm water “Khachmaz” (p,ρ,T) in Khachmaz area, Examined was Azerbaijan which has air conditioning and a constant temperature of T=293.15 K.Data from various sources were compared with the results obtained for the watery arrangement of water, toluene, and NaCl (m=2.96661 mol·kg-1). The gotten comes about are displayed graphically within the figures. In article, the reliance of the thickness of Khachmaz warm water of the Khachmaz locale of Azerbaijan on the temperature of ρ/(kg ∙ m-3) was measured within the high-precision temperature extend T = (278.15-468.15) in a tubular densimeter 5000M Anton-Paar DSA. Utilizing exploratory values at chosen temperatures, expository connections of warm water were set up. The gotten values are depicted by numerical conditions.

Summary: Friction brakes generate braking torque through the friction force between rotating (disk, drum) and non-rotating (pad, band) components. Drum-type brakes are primarily used in heavy-duty vehicles. To initiate braking, the shoe is pressed against the drum, creating contact pressure between the pressed surfaces. Tangential stresses arising from drum rotation produce the braking torque. The braking torque in the brake mechanism depends on the contact pressure and the coefficient of friction between the compressed surfaces. With a large compressive force, the deformations of the drum and shoe differ, altering the drum's round cross-section and causing variations in braking force at different moments. Therefore, accurately determining contact pressure is crucial for drum brakes. This article focuses on calculating braking torque by determining the deformations of the mold as close to real-world conditions as possible.

Summary: The work summarizes and critically analyzes the existing criteria for optimizing the methods of increasing and restoring the surface hardness of precision parts of machines and devices, shows ways to improve and clarify them, and also attempts to select optimal methods for increasing and restoring the surface hardness of precision parts of machines and devices and develop a generalized model. Various methods for increasing and restoring the surface hardness of parts of machines and devices with increased surface hardness pose the most urgent problem of choosing the optimal option for specific production conditions from among various technological solutions. This necessitates a further study of methods for increasing and restoring surface hardness and is based on three criteria: applicability, durability and technical and economic efficiency. The solution to the problem of substantiating the optimal method for increasing and restoring the surface hardness of machines and devices should be carried out using properly selected optimization criteria, using controllable factors that have the greatest impact on the costs of the technological process.

Summary: In the household refrigerator compressor is the main source of noise and heat, and the isolation of sound from the compressor in the air increases the thermal stress of his work and a significant reduction of energy efficiency of the refrigerator. Installing sound insulation panel in front of the compressor housing to reduce the noise level. The cooling system compressor oil is widely used in foreign and domestic refrigerators, implements "tropical" operating temperature Options refrigeration units tested at optimal doses of freon and constant permeability of the capillary tube. Soundproofing compressor housing leads to some increase in temperature of the motor windings and optimization of dose refrigerant with soundproofed compressor housing will increase the value of these indicators. The results confirm the possibility of reducing the noise of the refrigerator, through the use of an optimized heat removal from the cylinder head of the compressor.

Summary: The article solves a stationary hydromechanical problem about the movement of anomalous oil in a round cylindrical pipe according to the law of friction, i.e., according to the modified Maxwell model. When solving this problem, it is assumed that the direction of oil movement will coincide with the direction of the pipe axis. Between the 1st and 2nd cross sections of the pipe, a part with a length is taken. In this part of the pipe, radius size calculations are taken from the pipe axis. The speed of oil movement depends on the radius and decreases as it increases. At : ????=???? : ????=0 . From the condition of equilibrium of two forces, that is, the pressure force and the friction force, an expression was found for the radius of the flow core. Formulas are presented for the initial pressure Δ???? drop and for the shear stress ???? . To solve the differential equation of anomalous oil, a technique was used to replace a complex differential with a simple differential. A formula has been derived for the total oil flow rate in a pipe; a formula for pressure loss in the laminar mode of movement of anomalous oil in a pipe has been extracted. When Δ????≤Δ????0 the liquid in the pipe does not move, it remains at rest.

Summary: At a certain stage of oil and gas production, by increasing the efficiency of regulating water volumes in wells with water-cut production, it is possible to reduce water cut and increase current oil recovery. When developing oil fields, in order to maintain reservoir pressure and increase the oil recovery factor, water or various additives are pumped into the objects. During some stages of oil field development, various types of water (including water injected into the reservoir and external water filtered from the top) enter highly permeable areas and reach the production wells, and the amount of water in their products increases. In this regard, the main problem is the isolation of water entering the well by maintaining oil production. The presented work describes the development of nanostructured gels that easily penetrate into the water-saturated depth of the formation in flooded wells, effectively blocking culverts, without changing the phase permeability of oil, mathematical modeling of the process, and analysis of the results.

Summary: The national power assessment is very important in the development of state policy and international relations because it influences directly the strategic decisions and global positioning of the country. Although there are some models for calculating national power, comprehensive frameworks considering both traditional components and modern factors like scientific progress are still lacking, at least for emerging nations. In this paper, an improved formula of the calculation of national power is developed and applied to the Republic of Azerbaijan. Structural components such as population, territory, economy, military power, scientific and technical progress, political will, and geopolitical factors are analyzed in the paper. The research introduces a new measurement mechanism that combines fuzzy number scaling based on expert opinions. Our work demonstrates that the use of fuzzy assessment techniques in national power calculation is viable and therefore offers a more accurate assessment methodology. The model proposed quantify both the tangible and intangible aspects of national power and hence provide an integral assessment tool.

Summary: The article presents mathematical modeling and experimental study of microwave waveguide taking into account boundary value problems on the geometric middle of the domain. For the first time, general classes of local and nonlocal boundary value problems on the geometric middle of the domain for three-dimensional Bianchi-type equations for the electromagnetic field of microwave rectangular waveguide are investigated. New mathematical models of the electromagnetic field of microwave rectangular waveguide operating in the frequency range of 4,9-7,05 GHz are developed taking into account the nonlinearity of the medium, wave types and effective algorithms for solving the models are proposed, which made it possible to improve the electrical, magnetic, structural and operational parameters and characteristics of microwave rectangular waveguide. For E-type and H-type waves, 3D models of the distribution of electromagnetic field strengths in elementary regions of rectangular waveguide are developed. Experimental devices and functional circuits for measuring the parameters of the microwave path, including the electric and magnetic fields of a rectangular waveguide in a nonlinear state of the medium, were developed, and the parameters of the microwave rectangular waveguide were experimentally determined. Comparison of theoretical and experimental results of the electric and magnetic field strengths showed that the relative error for these parameters is 4%. This proved the adequacy of the theoretical and experimental results obtained. The proposed work differs from the existing [1-5] works in that, in this work, for the first time, the factor that the studied microwave waveguide is filled with nonlinear media is taken into account.