Obtained Calculation Results Research Articles

Application of an inertial vacuum trap for separation of the solid phase of carbon dioxide from the flow of fuel combustion products of boiler units

The technological process of low-temperature purification of fuel combustion products of boiler units from carbon dioxide by freezing it in a turboexpander and separating from the fuel combustion products flow in a separator is considered.The issue of separation of solid carbon dioxide from the flow of fuel combustion products of boiler units using a bag filter, an electric precipitator, a cyclone separator and an inertia-type separator is considered. Based on the analysis, the use of an inertial vacuum separator for separating the solid phase of carbon dioxide from the flow of fuel combustion products is proposed.Solidworks and ANSYS CFX modules were used for numerical modeling. To solve, the equations of continuity, motion, energy, and the k-ε model equations are used. The closing equation is for the effective and turbulent viscosity. There is also a description of the forces affecting the movement of the dispersed phase. The stream is considered lightly dusty.Numerical studies of the dispersed flow in the channel of an inertial-vacuum separator and in the previously used cyclone TsN-11 were carried out. The initial data for the calculation were taken based on the known mass flow rate and particle concentration, as well as from the continuity equation. From the results obtained, we can draw conclusions about a directly proportional relationship between the growth of the flow rate characteristics of the flow, the speeds along the flow path of the apparatus at the inlet and the resistance of the apparatus.Besides, based on the obtained calculation results, it was concluded that it is necessary to additionally install a rotary industrial air blower in order to create the necessary pressure drop in the inertial vacuum separator. The economic and environmental feasibility of installing a rotary air blower is consideredThe range of consumption of fuel combustion products has been determined at which the most effective purification of fuel combustion products from carbon dioxide in an inertial vacuum separator is possible within the technical characteristics of the refrigeration capacity of turborefrigeration machines.

ЖҰҚА ИЗОТРОПТЫ ПЛАСТИНАЛАРДЫҢ ИІЛУІН ТАЛДАУ

In the field of modern construction, thin isotropic plates are widely used. The development of calculation methods and mathematical models for thin isotropic plates of rectangular shape is an important issue. The article examines the bending of a rectangular thin isotropic plate. The method of separation of variables is employed to derive the plate calculation theory. New formulas for the function of deflection and internal forces of the plate are determined. A simplified version of the classical theory is presented, defining the solution to the plate bending problem using simple polynomials. The values of the deflection function and internal forces of a rectangular thin isotropic plate are presented in the form of tables and diagrams. The obtained calculation results are compared with Navier's method and the finite element method. The results obtained completely coincide with the results obtained by other methods and thereby confirm the correctness of the proposed version of the theory.

Tunable ferroelectricity of group Ⅳ–Ⅵ nanowires under composition modulation

Low dimensional ferroelectrics are anticipated to play a dominant role in micro/nano-electromechanical field. However, as their intrinsic size decreasing to one-dimension (1D), their ferroelectric polarization will weaken or even disappear, which severely limiting the further development of these promising materials. Therefore, it is of great significance to design one-dimensional ferroelectric materials with high-performance. In this work, first-principles calculations are employed to investigate the ferroelectricity and atomic configuration of MX (MX, M = Ge, Sn; X = S, Se) nanowires with composition tuning. Their ferroelectric characteristics, including spontaneous polarization Ps, transition barrier TL and TQ, Curie temperature Tc, as well as their stabilities, electronic structures, and transformation modes were systematically investigated. The findings indicate that their stability and forming tendency are strongly correlated with the bonding type. Moreover, all nine nanowires retained nanowires exhibit intrinsic 1D ferroelectrics with the maximal Ps of 6.40×10−10C/m for GeS nanowire and the minimum Ps of 3.95×10−10C/m for SnSe nanowire. The obtained calculation results indicate that the ferroelectric properties can be tuned by alteration of composition, which holds significant implications for the design and performance enhancement of 1D ferroelectric materials.

Investigation of Thermo-Electrical Instabilities in a Semiconductor as 2D Dynamical Systems

A semiconducting sample placed in cryogenic media with applied electric field generates low frequency oscillations of electric current and sample temperature and known to be thermo-electrical instabilities. Although observation of current oscillations on oscilloscope is possible, change of sample temperature cannot be detected experimentally. Description of the phenomenon through mathematical equations helps to understand relationship of the two variables as well as their connection to deep trap behavior that are involved in supporting the instability. Mathematical model for thermo-electrical instabilities in an n type semiconductor based on the two deep trap level model with non-degenerate electron statistics has been introduced in order to investigate the unique relationship between the change in time of both electric current flowing through a semiconductor sample and the sample temperature. The 3D dynamical system of nonlinear inhomogeneous ordinary differential equations has been investigated as component 2D dynamical systems (n,T), (n,n<sub>t</sub>) and (n<sub>t</sub>,T) for local behavior at isolated equilibrium and at points on individual trajectories, where n, n<sub>t</sub> and T are free electron concentration at conduction band, electron concentration at deep traps and temperature of a semiconductor sample accordingly. Each of the planar systems is expressed in canonical form and investigated as a Cauchy problem with a set of appropriate initial values. This paper presents investigation results of phase trajectories of the planar systems depending on a single parameter – the temperature of cooling media T<sub>0</sub>. Based on obtained calculation results of time sequences of the three variables n, n<sub>t</sub> and T, phase differences among these variables have been determined for different values of T<sub>0</sub>. It has been established that the change in sample temperature lags behind change in current and this lag increases with T<sub>0</sub>. Clearly defined correlations among systems (n,T), (n,n<sub>t</sub>) and (n<sub>t</sub>,T) are seen, being the result of balance between field aided and thermal ionization mechanisms for charge carrier generation and recombination processes. Thermal and field assisted generation mechanisms compete with one another in achieving steady non equilibrium state in the system depending on temperature of cooling media T<sub>0</sub>.

The analysis of the stability of the Cauchy problem in the cylindrical double-layer area

Ceramic protective coats, for instance, on turbine blades, create a double-layer area with various thermophysical properties and they require metal temperature control. In this paper, it is implemented by formulating a Cauchy problem for the equation of thermal conductivity in the metal cylindrical area with a ceramic layer. Due to the ill posed problem, a regularization method was applied consisting in the notation of thermal balance for the ceramic layer. A spectral radius for the equation matrix was taken as the stability measure of the Cauchy problem. Numerical calculations were performed for a varied thickness of the ceramic layer, with consideration of the non-linear thermophysical properties of steel and a ceramic layer (zirconium dioxide). A polynomial was determined which approximates temperature distribution in time for the protective layer. The stability of solutions was compared for undisturbed and disturbed temperature values, and thermophysical parameters with various ceramic layer thickness. The obtained calculation results confirmed the effectiveness of the proposed regularization method in obtaining stable solutions at random data disturbance.

Mathematical modeling of the combined heat supply system of the solar house

Today, improving energy efficiency in residential heat supply systems, saving fuel and energy resources, and increasing the efficiency of using devices based on renewable energy sources is an urgent issue. The aim of the article is to develop a mathematical model of the heat balance of one-story country houses based on the use of solar energy in a non-stationary mode and conduct theoretical research. The heat balance scheme of the solar house with autonomous heat supply and the electric-heat scheme of the physical model are proposed. Based on the proposed schemes, a mathematical model and calculation algorithm of the heat balance of a one-story rural house of the research object in non-stationary mode were developed, based on the mathematical modeling, the influence of the heat capacity of the wall structure on the temperature regime of the building was studied. The main temperature characteristics, which analyzed the change of the indoor air temperature of the building depending on the ambient temperature, were built on the basis of the MATLAB/SIMULINK program. The mathematical model of the building’s heat balance in dynamic mode and the obtained calculation results are recommended for use in the development of energy-efficient solar houses.

Estimation of CO emissions from 2 KAMAZ-54901 truck with the use of Regulation (EU) 2017/2400 methodology

Introduction (problem statement and relevance). For several years already, the world’s leading countries are managing programs aimed at decreasing СО2 emissions from trucks. These programs imply actual (field) testing of components and simulating of vehicle driving according to the test cycles in the special software (SW). In Europe, Regulation (EU) 2017/2400 requires that manufacturers produce and open source such calculations when registering new trucks (heavy-duty vehicles) in the EU territory. The purpose of the study is to compare the CO2 emission level from trucks made by the European manufacturers and from a modern truck produced by KAMAZ PTC.Methodology and research methods. The truck driving was simulated with the use of Regulation (EU) 2017/2400 methodology in the VECTO software. Scientific novelty and results. The СО2 emissions from the modern truck produced by KAMAZ PTC were calculated with the use of Regulation (EU) 2017/2400 methodology in the VECTO software. Practical significance. The obtained calculation results can be used for optimization of the KAMAZ vehicle parameters in order to decrease fuel consumption and СО2 emissions

RESEARCH OF THE CHANGE IN THE CONSOLIDATED MASS IN FLAT MULTI-LINK MECHANISMS

Purpose. Determination of the equation of motion of the crank-connecting mechanism using the methods of researching the motion of flat multi-link mechanisms. Development of the dependence using the theorem on the change in kinetic energy of the mechanical system for determining the total mass of flat mechanisms when the angle of rotation of the driving link of the flat mechanism changes.
 Research methods. Dynamic analysis of the mechanism. The method of reducing forces and masses. Mathematical determination of the kinetic energy depending on the angle of rotation of the crank of a flat mechanism. Regression processing of the obtained calculation results and their subsequent correlation analysis were carried out using computer software for the analysis and visualisation of scientific and statistical data – «SigmaPlot» from the company «Jandel Corporation».
 Results. A calculated formula for the change in the combined mass depending on the angle of rotation of the crank was obtained. The existence of a sinusoidal relationship between the calculated parameters (crank angle and reduced mass) was established. The correlation analysis of the obtained function showed a sufficiently high degree of relationship between the calculated data and the mathematical dependence, while the correlation coefficient was r = 0.972. The graph of the determined mathematical dependence also showed a fairly high correlation between the specified parameters. The resulting equation can be used for systems with one degree of freedom. For mechanisms with several degrees of freedom, the law of change of the combined mass will be different for each degree of freedom.
 Scientific novelty. Using the calculated formulas of kinetic energy for planar mechanisms, the law of change of the reduced mass in planar mechanisms, which takes into account the rotation of the crank around its own axis, is obtained.
 Practical value. When designing flat crank mechanisms, it is necessary to take into account the effect of inertial forces, the value of which depends on the mass and acceleration. This makes it possible to calculate correctly the dynamic loads on the parts of the flat mechanism (bearings, etc.). The obtained mathematical dependence of the change in the combined mass on the angle of rotation of the leading link of the mechanism makes it possible to analyse the change in the combined moment of inertia, which in turn affects the change in torque.

Planing of the Finite Aspect Ratio Plate at Subsonic, Transonic and Supersonic Speeds

The mechanics of underwater supercavitating projectiles are currently being extensively researched. The disadvantage of such projectiles is their movement instability. There is a proposal to use stern planing plates to stabilize projectile’s movement. However, the hydrodynamic characteristics of planing plates are known only for low subsonic speeds. This article describes a load study on a planing plate at subsonic, transonic and supersonic speeds with detached and attached shock waves. The obtained calculation results of normal forces satisfactorily agree with the known theoretical solutions and experimental data and can be used to calculate the motion stabilization of supercavitating underwater projectiles with planing stern plates.

Theoretical determination of speed of sound and fourth virial coefficient by using Kihara (12–6) potential

Abstract In this paper, a new theoretical approach is suggested for the numerical calculation algorithm of the fourth virial coefficient and its components with the Kihara potential. For the first time, this study reports the results of the fourth virial coefficient over the Kihara potential. The proposed method can be used to calculate the thermodynamics properties of gases with developed correctness. The method is tested for some molecules and as an example of application, the proposed method has been performed for gases of C3H8 and SF6. The obtained calculation results have been compared with the theoretical and experimental data and the results have been found to be consistent with the literature data. It can be seen from the application that the calculation of the fourth virial coefficient with the Kihara potential can provide important results in the calculation of the thermophysical properties of other real systems.

ON THE DETERMINATION OF THE SPECIFIC HEAT FLUX VALUE IN A PULSE DETONATION ENGINE’S CHAMBER

Abstract. The development of detonation engines (DE) is one of the most promising areas of rocket and space engine manufacturing. They are more efficient as compared to the liquid rocket engines and are structurally simpler. At the same time, the detonation engine chamber’s structure is subjected to much higher thermal loads. Therefore, at the development stage of the DEs, to create an efficient cooling system for the engine’s chamber, it is necessary to be able to determine the value of thermal energy, which is absorbed by the walls of the DE’s chamber. The goal of this research is to determine the specific heat flux from the detonation products towards the walls of the pulse detonation engine’s (PDE) chamber. The task of the work is to establish the methodology for calculating the values of the specific heat flux transmitted to the walls of the PDE’s chamber. The main tools for solving this problem are the method of mathematical simulation using computational fluid dynamics (CFD), and the method of regression analysis. The main results of this study: the possibility to utilize the well-known Ievlev methodology to determine the convective specific heat flux for the PDE’s chamber was analyzed; it was shown that for the conditions of the PDE’s chamber, the Ievlev methodology calculation results differ significantly from the experimental data, which can be explained by the presence of a clearly pronounced non-stationary nature of the detonation process; it was proven the utilization of the Viegas formula to obtain the values of the convective specific heat flux for the PDE’s chamber gives better results as compared to the known experimental data and the results of the mathematical simulations; it was also demonstrated that the average integral value of the specific heat flux, determined by the described methodology, can be used to calculate the thermal state of the PDE's chamber. Conclusion: a methodology for calculation of the specific heat flux value for the pulse detonation engine's chamber was proposed. The obtained calculation results are in good agreement with the results of mathematical simulations and known experimental data. The described methodology can be used in the design of cooling systems for the pulse detonation engine’s chambers.

Information Control on Inventory Study at In One of The Garment Companies in Bandung

The objective of this study is to examine the impact of the Finished Goods Inventory Accounting Information System on the internal control of finished goods inventory at PT. Partners Adi Jaya Manunggal in Bandung City. Based on the obtained calculation results, it has been determined that the Accounting Information System (X) for Finished Goods Inventory is deemed to be of satisfactory quality, as indicated by a score of 3.39. The internal control system for managing finished goods inventory (Y) has demonstrated effective performance, as evidenced by a value of 3.37. The optimization and effective utilization of a precise accounting information system for finished goods inventory is expected to enhance internal control measures for such inventory.
 The research employed a descriptive verification research method at PT. Partners Adi Jaya Manunggal in Bandung City. In order to gather data and information that will substantiate this research, the approach involves the collection of secondary data and the utilization of linear regression hypothesis testing. This methodology aims to offer a comprehensive understanding of the impact of the Finished Goods Inventory Accounting Information System on the Internal Control System for Finished Goods Inventory.
 According to the findings of the study, the outcomes of the linear regression analysis indicate that the equation Y = 8.006 + 0.817. This finding indicates that a majority of the population in Mitra Adi Jaya Manunggal, Bandung City, accounts for 63.3%, while the remaining 36.7% represents an unexamined variable of influence.

Influence of Accounting Information Systems on Internal Control of Receivables

This study aims to investigate the impact of variables related to the accounts receivable accounting information system and accounts receivable internal control on a telecommunications company located in Bandung. Based on the obtained calculation results, it has been determined that the accounting information system for accounts receivable can be classified as moderately satisfactory. At the same time, the internal control measures for accounts receivable can also be classified as moderately satisfactory.
 The research findings indicate a significant correlation of 0.840 between variables X and Y, suggesting a strong relationship between the accounts receivable accounting information system and accounts receivable internal control. According to the analysis conducted using simple linear regression, it has been shown that the relationship between the dependent variable Y and the independent variable X, representing accounts receivable in the accounting information system, can be expressed as Y = 7.180 + 0.729X. This condition implies that for each unit rise in the accounts receivable; there is an associated increase of 0.729 units in the dependent variable. The coefficient analysis reveals that the accounts receivable accounting information system significantly contributes to the internal control of accounts receivable, accounting for 70.6% of the overall influence. The remaining 29.4% can be attributed to various other factors.

A study on the cross-section data of 43,44m,46,47Sc isotopes via (d,x) reactions on natural abundance targets under the effects of deuteron optical models

Many studies have investigated the influence of theoretical models and factors involved in the acquisition of cross-section data of a nuclear reaction. The implications of different models of various variables such as level density, gamma strength function, and optical potentials on cross-section calculations whether used solo or jointly are investigated in a significant portion of the works conducted in this perspective. The aim of this particular study is to investigate the influence of different optical models on the cross-section calculations in production of several scandium isotopes, known for various medical uses, from several targets with natural abundances by (d,x) reactions. For this purpose, the cross-section calculations using five available deuteron optical models of TALYS code in natTi(d,x)43Sc, natTi(d,x)44mSc, natTi(d,x)46Sc, natTi(d,x)47Sc, natV(d,x)47Sc and natCr(d,x)47Sc reactions were performed and the obtained calculation results were compared with the experimental cross-section data gathered from the literature. To understand whether there is a significant and consistent relationship between the experimental data and the calculation results, both have been plotted together and analyzed with the naked-eye. In addition, the calculations of the mean standardized deviation, the mean relative deviation, the mean ratio and the mean square logarithmic deviation were performed in order to evaluate the results numerically.

HYDRODYNAMIC-WAVE CALIBRATION OF POTENTIALS IN MAXWELL’S EQUATIONS: NON-LINEAR DYNAMICS AND COHERENCE, COLLAPSE, EXPANSION AND EXCHANGE INTERACTION OF INERTIAL DISSIPATIVE-COLLECTOR DISTURBANCES IN NON-EQUILIBRIUM MEDIA IN THE COMPLEX SPACE. SPIRAL TURBULENCE AND COHERENT STRUCTURES OF THREE-DIMENSIONAL TIME

The results of the hydrodynamic-wave calibration of the potentials in Maxwell’s equations and their analogs for the gravitational field, which combine Euler’s hydrodynamics, Maxwell’s electrodynamics, and d’Alembert’s wave apparatus with quantum principles, are given. The nonlinearity of the equations for the vector-potential with the velocity dimension ensures the interrelationship of different field forms and the cascade transport of energy by the disturbance spectrum. The obtained solutions of these equations for inertial dissipative-collector disturbances, which are characterized by a balance of local and convective acceleration, and also balance local dissipation (accumulation) with local metainertia. The vector-potential (wave function) of such forms includes a complex Euler exponent, the phase of which depends on the coordinates of the disturbances paired in the complex space – without distinguishing its real or imaginary half. Reasoned constancy of the phase, which ensures the coherent nature of the propagation of running field forms in complex space, as well as in topologically adequate three-dimensional time. The latter is considered in a cylindrical coordinate system that combines spiral and jet time forms. The correspondence of the components to the Laplace operator (in the spherical spatial coordinate system associated with the pair of disturbances) with respect to the near-acting centrifugal energy of repulsion and the long-range exchange energy of attraction, which collectively provide the mechanisms of collapse, expansion, and dynamic balance of the pair, has been revealed. Coherent resonant forms of motion with a three-dimensional topology of time are highlighted, which are widely represented, in particular, on the spectra of collider resonances, as well as on the spectra of technical, hydrodynamic, geophysical, and space turbulence. It is noted that such turbulence is described precisely by Maxwell’s equations in the hydrodynamic-wave calibration of potentials, and not by the Navier-Stokes equations, or by the truncated equations of magnetohydrodynamics, which completely ignore the displacement current in Maxwell’s equations. The obtained calculation results are confirmed by actual data in the systems of different levels of the organization. The main role of inertial dissipative-collector disturbances in the processes of dynamic thermoregulation of the Earth’s climate during the cyclical change of climatic optimums during ice ages has been established. In this context, criticism of the current noisy concepts of global warming, which exaggerate anthropogenic factors without taking into account the dominant natural factors, is presented. It is indicated that these factors should be considered in an expanded format of complex space and three-dimensional time without artificial constructions and self-limitations inherent, in particular, in modern standard physical models Lambda-CDM and SM.

Effects of Deuteron and Alpha Optical Model Potentials on the Production Cross–Section Calculations of Some Radiobromine Isotopes

The extensive use of radioisotopes in diverse fields, particularly in medical studies for diagnosis and treatment, is one of the outcomes of evolving technology and improved scientific research. Among the various radioisotopes used for medical purposes, an example that can be highlighted considering their properties and utilization possibilities is radiobromine isotopes. It is obvious that both experimental and theoretical studies make significant contributions to the literature on medically relevant radioisotopes. The cross–section, which is the data connected with the occurrence of a reaction, is one of the theoretical metrics that may provide information to researchers. The framework of this study was constructed by taking into account the importance of radiobromine isotopes in medical applications as well as the effects of some parameters that might have an impact on their production cross–section calculations. In this context, the impact of five deuteron and eight alpha optical model potentials, which are available in the 1.95 version of the TALYS code, on the production cross–section calculations of 75-77Br radioisotopes through some (d,x) and (α,x) reactions have been studied. The obtained calculation results were compared visually and numerically with the experimental data available in the literature for each reaction, and the outputs were interpreted.

Influence of the Numerical Modelling Methods on Dispersions and Errors of Analysis Results of Ship Hull and Deckhouse Vibrations

Abstract Ships’ (especially containers) vibrations significantly impact navigation safety. The presented analyses aims to identify the main forces exciting the ship’s superstructure and hull vibrations, test their influence on vibration levels, and verify the assumptions of the computational methodology. Two container ships were analysed. The influence of different modeling methods on the obtained calculation results was investigated. The impact of various operating parameters on the vibration level was also analysed. The numerical analyses results are compared with some empirical formulas. As a result, the calculation confidence level was estimated. The calculation results have been verified by comparison with measurement tests carried out on the real ship.

Computer simulation of ice film sputtering from Au(111) surface

Mass spectrometry of secondary ions represents a combination of analytical methods, which allows you to study the molecular characteristics of the solid state. On the basis of this method, the use of charged charging frequencies is directed at the power, usually in the range of tens of thousands of electron volts. Based on the molecular dynamics method, we simulated sputtering process in the form of water molecules and clusters of water films covering Au(111) on the surface at normal incidence. It is shown that the obtained mass spectra of sputtered particles contain peaks related to several water molecules. The analysis of the obtained results showed that peaks were formed on the mass spectrum of sputtered particles, which belong to water molecules, water clusters, and Au atoms. The results played a huge role in studying the surface of thin films and molecular spectroscopy. The obtained calculation results showed that the number of incident particles directly affects the sputtering process, that is, the greater the number of incident particles, the more intense the process of sputtering of the atoms of the upper layers of the substrate. This is due to the fact that the incident ions, destroying the structure of the crystal, namely, violating the periodicity of the upper atomic layers, remain in the substrate of the crystal.

Influence of the Shielding Winding on the Bearing Voltage in a Permanent Magnet Synchronous Machine

This article presents selected methods of limiting the bearing voltages of synchronous machines with permanent magnets supplied from power electronic converters. The authors analyzed methods based on the use of various shielding windings placed in slot wedges and mounted in the stator end-winding region. The values of the parasitic capacitances of the machine, on which the levels of bearing voltages depend, were determined using the finite element method. Three-dimensional simulation models were used for the calculations. The analysis of the influence of the shielding windings on the bearing voltage waveforms was conducted on the basis of circuit models with two- and three-level converters. The obtained calculation results indicate a high potential in limiting bearing voltages.

Mathematical Modeling of the Combined Heat Supply System of a Solar House

Today, increasing energy efficiency in residential heating systems, saving fuel and energy resources, and improving the efficiency of using devices based on renewable energy sources is an urgent issue. The purpose of the article is to develop a mathematical model of the heat balance and conduct a theoretical study of one-story rural houses based on the use of solar energy in a non-stationary mode. To achieve this goal, an experimental one-story solar house with autonomous heat supply was built. The heat supply of the experimental solar house mainly uses solar energy, and when the heat supply load exceeds this load, the traditional boiler device is used. The power supply of the experimental solar house is provided by a solar panel (photovoltaic converter). A heat balance scheme for a solar house with autonomous heat supply and an electrothermal scheme of a physical model are proposed. Based on the proposed schemes, a mathematical model of heat balance and a calculation algorithm based on the heat balance equation of the dynamic state of the heat supply system of a one-story experimental solar house in a non-stationary mode have been developed. On the basis of mathematical modeling, the influence of the heat capacity of the wall structure on the temperature regime of the building was studied. On the basis of the MATLAB-Simulink program, the main temperature characteristics were built, on which the change in the temperature of the internal air of the building was analyzed depending on the ambient temperature. On the basis of the program, a modular scheme of the dynamic model was built. Based on the modular scheme, the results of the experiment on changing the air inside the solar house and the outdoor temperature are presented in the form of a graph. The mathematical model of the thermal balance of the building in dynamic mode and the obtained calculation results are recommended for use in the development of energy-efficient solar houses.