Mutual influence of currents in plane inductor system with solenoid between two massive conductors

Introduction. Inductor systems, as tools for metal processing, widely used in industrial technologies using the energy of powerful pulsed electromagnetic fields. Problem. A common disadvantage of the known works on the creation of tools for magnetic-pulse impact on conductive objects has the use of physical and mathematical models, in which the exciting currents do not depend on the ongoing electromagnetic processes. Such the assumption, have distorts the picture of the real energy in the working area of the inductor system. Goal. To obtain design ratios and numerical estimates of the mutual influence of exciting and induced currents of a flat inductor system with a circular solenoid located between massive well-conducting objects, moreover to carry out a theoretical analysis of electromagnetic processes in this system. Methodology. Have applied integrating Maxwell’s equations using the Laplace and Fourier-Bessel integral transformations in the approximation of the ideal conductivity of the metal objects to be processed. Results. The calculated relations for the theoretical analysis of electromagnetic processes have obtained in the high-frequency approximation. It shown that the inductance of the studied system decreases as the objects being processed approach the solenoid and increases as they move away from it. It found that for the invariability of the power indicators, of the proposed tool, a corresponding correction of the amplitude (on average up to 20 times) of the exciting current has necessary in the solenoid winding. Originality. For the first time, the tool design with a circular solenoid located between the massive metal objects has proposed for flat magnetic-pulse stamping. As a result of the theoretical analysis, the influence of electromagnetic processes on the currents flowing in the system has confirmed. Practical significance. The use of the results obtained will allow to increase the efficiency of the tool of magnetic-pulse technologies, and to reduce the energy costs for performing the specified production operations.

Assessment of the technical condition of ship hulls using mobile magnetic devices

Оценку технического состояния корпуса судна проводят с применением диагностических датчиков. С помощью них замеряются, например, толщина обшивки, параметры бухтин, вмятин, гофрировки. Процессы эти трудоемкие и достаточно сложные. Проблемой автоматизации таких операций является удержание измерительной аппаратуры на криволинейной поверхности корпуса судна и перемещение аппаратуры по ней. Одним из вариантов решения проблемы является применение подвижных тележек с установленными на них магнитными устройствами. В данной работе исследуются вопросы влияния кривизны обшивки корпуса судна на параметры подвижной магнитной системы. Представлены расчетные схемы для различных компоновок, физические и математические модели. Анализ полученных математических выражений позволил сделать выводы по вариантам размещения, по зазору и скорости его изменения, клиренсу транспортного устройства, углу между опорной поверхностью и торцевой плоскостью магнита, который приводит к уменьшению силы притяжения. Учтен начальный зазор. Проведены расчеты зависимостей изменения радиуса кривизны корпуса судна от колеи и конструктивной схемы мобильных устройств. The assessment of the technical condition of the vessel's hull is carried out using diagnostic sensors. They are used to measure, for example, the thickness of the skin, the parameters of camber, dents, corrugations. These processes are time-consuming and quite complex. The problem of automation of such operations is the retention of measuring equipment on the curved surface of the hull of the vessel and the movement of equipment along it. One of the solutions to the problem is the use of movable trolleys with magnetic devices installed on them. In this paper, the issues of the influence of the curvature of the hull covering on the parameters of the mobile magnetic system are investigated. Calculation schemes for various layouts, physical and mathematical models are presented. The analysis of the obtained mathematical expressions allowed us to draw conclusions on the placement options, on the gap and the speed of its change, the clearance of the transport device, the angle between the support surface and the end plane of the magnet, which leads to a decrease in the force of attraction. The initial gap is taken into account. Calculations of the dependences of changes in the radius of curvature of the hull of the vessel on the track and the design scheme of mobile devices are carried out.

Visualization of physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB to diagnose the condition of external heat supply networks

Nowadays, Russia has the longest heating network system in Europe (about 125 000 km in total). Given the constant growth in the volume of construction space, the length will constantly increase. Consequently, there is a request to increase the level of reliability of heat supply networks. It is possible to satisfy the request only by increasing the volume and quality of comprehensive diagnostics of heat supply networks with simultaneous reduction of time costs. This is possible only if a new generation of measurement and computing complex (MCC) is developed for the diagnosis of heat supply networks. The team of authors examines the features of the information environment in heat supply networks, separately noting the possibility of switching the flow from single-phase to multi-phase and back. The paper proposes to consider a solution to a problem that arises when trying to visualize physical and mathematical models of thermodynamic processes of single-phase flows using MATLAB. It consists in the fact that the desired physical and mathematical model should describe the thermodynamic processes of a single-phase flow, but taking into account that this flow moves in the external heat supply network. The possibility of using the MATLAB functional environment for developing a model based on visually oriented programming is considered in detail, which allows us to lay the foundations for further forecasting the development of the heat supply system.

Overview of the Constitutive Model and Numerical Calibration by FEM to Compute Bearing Capacity and Embankment-Core Deformability

Numerical modeling is a powerful tool to determine the stress-strain relationships of structures. However, for a reliable application, physical and mathematical models must be calibrated and validated. This paper presents an overview of numerical calibration through the finite element method and plate-load tests in an embankment. Additionally, an analysis of the constitutive models used in soils is performed, and the elastic-plastic constitutive model of Mohr-Coulomb was selected since it is the best suited for this study. The results from three test areas within a refinery project that the Cuban government undertook in the province of Cienfuegos are used. The numerical model used in this study was calibrated by means of the error theory and the non-parametric hypothesis tests from Mann-Whitney U. From the practical point of view, this study gives two procedures to calibrate the numerical model with experimental results.

THEORETICAL ANALYSIS OF MEMBRANE AIR DEHUMIDIFICATION IN AIR CONDITIONING SYSTEMS

The paper presents a simulation of the process of removing moisture from the air in air conditioning systems using construction vapor-permeable membranes. The existing classical physical and mathematical models are considered and analyzed. Based on the analysis of classical models, a schematic and corresponding theoretical mathematical model of air dehumidification with a semipermeable building membrane with certain characteristics for possibilities of use in air conditioning systems is developed and presented. The data of calculations of moisture release from air for the developed model are given. As a result of analytical researches the correct data for possible use in air conditioning systems are received. Key words: air conditioning systems, air dehumidification, semipermeable membrane, permeability, membrane air dehumidification, convective flow, diffusion flow, moisture permeability.

Biosensor concept and data input to biomedical infornation systems

Background. In present publication we generalized and analyzed deeply the experience of some biosensors studying in biophysical experiments with aim to incorporate them further to electronic information systems. Output biosensor electrical signals were input ones to electronic information system making their connection into joined bioinformation system. Materials and methods. Methods of comparative analysis of the characteristics of input and output electrical information signals of biosensor were applied; its physical and mathematical models were developed. For biosensor properties studies the methods of transmembrane electric currents recording in voltage-clamp mode as well as patch-clamp on hippocampal neuronal membranes were used. Results. Biosensor concept and their general characteristic were given, corresponding prototypes were observed. The physical model of biosensor was developed and some test results of this device were suggested. The biosensor was examined as abstraction in consistent unity of its functions: signal receiver — filter — analyzer — encoder/decoder. A brief mathematical description of biosensor functioning was given as well as corresponding algorithm. As a result of performed works the possibilities of this biosensor incorporation to bioinformation electronic systems were substantiated and the example of such system «EcoIS» was observed. Conclusion. In conclusion following results of the works were summarized. The detailed description of technical devices — biosensors as elements of biomedical information systems were done as well as analysis of electrical information signals at output of biosensor, its ability to encode information and detailed analysis of the possibility to incorporate this biotechnical device into electronic information systems due to biosensor output electricals signals.

No Catalytic Performance Analysis of Gasoline Engine Tapered Variable Cell Density Carrier Catalytic Converter

Improving the flow field uniformity of catalytic converter can promote the catalytic conversion of NO to NO2. Firstly, the physical and mathematical models of improved catalytic converter are established, and its accuracy is verified by experiments. Then, the NO catalytic performance of standard and improved catalytic converters is compared, and the influences of structural parameters on its performance are investigated. The results showed that: (1) The gas uniformity, pressure drop and NO conversion rate of the improved catalytic converter are increased by 0.0643, 6.78% and 7.0% respectively. (2) As the cell density combination is 700 cpsi/600 cpsi, NO conversion rate reaches the highest, 73.7%, and the gas uniformity is 0.9821. (3) When the tapered height is 20 mm, NO conversion rate reaches the highest, 72.4%, the gas uniformity is 0.9744. (4) When the high cell density radius is 20 mm, NO conversion rate reaches the highest, 72.1%, the gas uniformity is 0.9783. (5) When the tapered end face radius is 20 mm, NO conversion rate reaches the highest, 72.0%, the gas uniformity is 0.9784. The results will provide a very important reference value for improving NO catalytic and reducing vehicle emission.

Dissolution Mass Transfer of Trapped Phase in Porous Media

Dissolution mass transfer of trapped phase (TP) to flowing phase (FP) in porous media plays significant roles in hydrogeology, e.g., groundwater contamination by non-aqueous phase liquids, groundwater in-situ bioremediation, and geological carbon sequestration. In this chapter, this phenomenon is described. First, the physical and mathematical models are given. Afterwards, various conditions affecting this process, i.e., porous media characteristics, capillary trapping characteristics, flow bypassing, TP characteristics, and FP velocity, are discussed. These various conditions are described based on three parameters affecting the dissolution mass transfer: TP interfacial area ( A ), TP dissolution ratio ( ξ ), and mass transfer coefficient ( k ). Eventually, models to predict the mass transfer are formulated based on non-dimensional model. All of the data in this chapter are based on the experiments obtained by using micro-tomography and a series of image processing techniques from our latest works.

Self-preservation Effect of Gas Hydrates

This work was performed to improve the storage and transportation technology of gas hydrates in nonequilibrium conditions. At atmospheric pressure and positive ambient temperature, they gradually dissociate into gas and water. Simulation of the gas hydrate dissociation will determine optimal conditions for their transportation and storage, as well as minimize gas loss. Thermodynamic parameters of adiabatic processes of forced preservation of pre-cooled gas hydrate blocks with ice layer were determined theoretically and experimentally. Physical and mathematical models of these processes were proposed. The scientific novelty is in establishing quantitative characteristics that describe the gas hydrates thermophysical parameters thermophysical characteristics influence on the heat transfer processes intensity on the interphase surface under conditions of gas hydrates dissociation. Based on the results of experimental studies, approximation dependences for determining the temperature in the depths of a dissociating gas hydrate array have been obtained. Gas hydrates dissociation mathematical model is presented.

Mathematical models and methods of numerical investigation of processes which accompany aircraft icing

The study of aircraft icing modes, in which it is necessary to take into account the effect of droplet crushing, is of great interest in calculating the icing of aircraft, optimizing the hydrophobic and anti-icing properties of coatings, and is relevant in a number of other practical applications. Of great practical importance is the development of high-performance methods for calculating the interaction of aerosol flows with a solid. This work is devoted to the development of a model of particle dynamics, as well as a model of fragmentation of supercooled droplets of an aerosol flow during its interaction with the surface of a streamlined body. Developed physical and mathematical models can be used in software systems for numerical modeling of aircraft icing.