The Pairing Analysis Improvement of Magnetized Structure in Electromagnetic Bulging Process in Case of Tube with Field Shaper

In the current practical science, the accuracy in the formability of metal alloys being the goal when using electromagnetic forming (EMF) technology, which is a high-speed processing technology that uses Lorentz forces to achieve plastic deformation of sheet metal;according to the previous analysis, the results have shown that in most cases, the Lorentz force acting on the workpiece (metal) is not uniform, there are uneven axial deformations of the metal plates which prevent the rapid advancement of today’s technology. In this article, we presented some advanced analyzes which will lead us to improve the technical solution for the problems of non-uniform axial deformations of the metals in the traditional tube electromagnetic forming technology (EMF). A field shaper is used as a practical forming tool to influence the magnetic field and magnetic pressure distribution, thereby improving the forming ability and result during the electromagnetic forming (EMF) process and we see that induced eddy current control is realized by changing the structural parameters of the magnetic field shaper;which improves the strength and controllability of the magnetic force that acts on the workpiece;thereby a greater radial magnetic pressure can be achieved with field shaper than the case without it;the field shaper regulates the electromagnetic force, the distribution of the magnetic pressure decreases, and the uniform force area of the tube increases which effectively enhances the uniform range of the pipe electromagnetic bulging and the electromagnetic induction coupling between the coil and the metallic workpiece is generally required to produce the Lorentz forces. Using COMSOL Multiphysics® simulation software helped us to accurately represent the real world, simulating multiple physical effects that happened in this model during the process.

Distribution of Si particles in hypereutectic aluminum alloy tubes prepared under electromagnetic field

Hypereutectic Al-Si alloy tubes were produced by centrifugal casting process using an electromagnetic field (EMF). A gradient distribution of the primary Si particles was formed along the tube thickness direction. In the absence of EMF the primary Si moves to inner periphery with increasing rotation speed. The distribution of primary Si can be controlled by the EMF. With increasing electromagnetic field intensity, the primary Si moves from the inner periphery to the outer periphery of the tubes. Most of the primary Si can be driven to the outer if the electromagnetic field intensity is increased to a certain value. It is found that the particle distribution and local volume fraction vary with both the rotation speed and the electromagnetic field intensity.

THE ELECTROMAGNETIC FIELD CALCULATION AND ANALYSIS OF LEVITATION MELTING WITH COLD CRUCIBLE

In this paper, using the quasi-3D coupled current method, the influences of structure of cold crucible, the power frequency, the electricity property of melt, the coil position and current on the electromagnetic field (EMF) and the levitation characteristics in the melting processes are analyzed. It is shown that in the processes of levitation melting with cold crucible, the power frequency and cold crucible structure are the decisive factors for the ability of magnetic flux penetrating into cold crucible. The magnetic flux density in cold crucible is reduced as the increasing of power frequency, and this tendency becomes stronger when the power frequency is higher than 100kHz. The segmented structure of cold crucible can reduce the induction eddy in itself effectively, and the higher the power frequency is, the better the result is. So, a cold crucible can be segmented into 16-20 sectors for high frequency electromagnetic field and/or 8-12 sectors for lower frequency one. It is also shown that the levitation force of melting charge is related to coil current as a parabolic function.

Effect of Distribution of Magnetic Flux Density on Purifying Liquid Metal by Travelling Magnetic Field

The distribution of the magnetic flux density in the magnetic field generator which provided travelling magnetic field was determined. The experiments using liquid gallium and aluminum silicon alloy to observe the turbulent flow or remove inclusions were performed to obtain the basic principles how the distribution of the magnetic flux density took effect on removing inclusions from molten metal by electromagnetic field. The suitable area in the field for purifying metal was suggested.

Cellular Psychology Assumption: Based upon Exterior Algebra, It Contributes to Explaining the Variability of the Bioeffects of Magnetic and Electromagnetic Fields

According to its own purposes, including survival, the cell reacts to the conditions of its medium. Such a vital phenomenon implies relational energetics. It includes unconscious psychic energy whose regulating model is the Life and Sense archetype. Its relational power could result from a natural algebraic property of extension. This extension can extend any organic magnitude to 4D event. Thus it allows some perception of the extracellular structure variations. This perception applies to moving forces of the cell signaling activators, through psychic energy. This psychical energy includes a potential, the cell attitude or status, and psychic moving forces, or tendencies. Insofar as the psychic potential is sensitive to proton structures, and the psychic moving forces are excitable by electron exchanges, a phase shift between us may occur. Medium stimulation by adequate magnetic fields could modulate this phase shift in a therapeutic direction.

Exposure to a 2.5 GHz Non-ionizing Electromagnetic Field Alters Hematological Profiles, Biochemical Parameters, and Induces Oxidative Stress in Male Albino Rats

Modern technology has witnessed milestone achievements in the telecommunication industry.However,the widespread application of telecommunication technology is believed to heighten electromagnetic field(EMF)‘pollution’in our environment[1]and subject living organisms to various sources of electromagnetic emissions.These emissions include;microwaves.

Behavior of particles in front of metallic solid/liquid interface in electromagnetic field

The first part deals with the behavior of particles theoretically, and the critical electromagnetic force needed to alter the behavior of particles was deduced under different conditions. It was proposed that applying electromagnetic force would change the distribution coefficient of the particles. By using the data from literatures, the migrating rate of SiC particle by electromagnetic force was calculated, which is far more than the critical rate of solidifying interface which will result in the engulfment of the SiC particle in the Al SiC matrix metal. Therefore the possibility of controlling the behavior of the particles in front of the solidifying interface by electromagnetic field was confirmed. In the second part, by using simulative experiments, the man made alternation of the behavior of the particles in front of the solidifying interface under electromagnetic field was observed, and the idea of changing the distribution of the particles in solidified metal by electromagnetic force was verified experimentally. It is shown that, the particle, which would be engulfed by the solidifying interface, would escape from the interface under electromagnetic buoyant force (EMBF), and the particles adherent to the interface would migrate toward it and be engulfed finally under EMBF. Further more, the particles being pushed by the interface would stay at the interface, the repulsive force exerted on the particles would be counteracted by EMBF, and then the particle would turn to be engulfed. Adjusting the direction and magnitude of EMBF could alter the distribution of the particles in the solidifying metal.

MICROSTRUCTURE AND MACROSEGREGATION OF Al-7%Si ALLOY SOLIDIFIED UNDER COMPLEX EFFECTS OF ELECTROMAGNETIC AND CENTRIFUGAL FORCES

Macrosegregations and microstructures of Al-7%Si alloy solidified under complex of fects of magnetic field and centrifugal forces are studied by means of a set of selfdesigned electromagnetic centrifugal casting (EMCC) device. It is shown that electromagnetic field (EMF) has an important effect on the macrosegregation of centrifugal casting specimen of Al-7%Si alloy in two respects: one is that there exists always a kind of convection in the liquid in front of the S/L interface caused by effect ofthe electromagnetic force; the other is that different atomic clusters of solidparticles with different physical characteristics are subjected to quite different electromagnetic (Lorentz) force. Therefore, their movements get changed. In addition, the formation process of a complex band structure consisting of primary α-Al dendrites and (α-Al+β-Si) eutectics in hypoeutectic Al-Si alloys during EMCC and the effect of EMF are discussed.

THE COMPUTATION AND EXPERIMENT ANALYSIS OF ELECTROMAGNETIC CONTINUOUS CASTING WITH SOFT-CONTACTED MOULD

In this paper, coupling the quasi-3D numerical simulation of electromagnetic field and the experiments of continuous casting with soft-contacted mould with some metals such as tin, aluminum, copper and steel, the electromagnetic characteristics of continuous casting with soft-contacted mould is analyzed. It is shown that the electromagnetic pressure on the surface of billet is increasing with the rising of power frequency as a logarithmically parabolic function, with that of electric conductivity of billet as a power junction, and with that of the current in inductor as a parabolic junction.

Electric-magnetic-force characteristics of rare earth barium copper oxide superconductor high-field coils based on screening effect and strain sensitivity

Rare earth barium copper oxide(REBCO)is the most researched and commercialized second-generation high-temperature superconducting material.Due to the anisotropic structure,strong deformation sensitivity,and central field errors caused by screening current effects,it is still a challenge for commercialization applications.In this study,the transversely isotropic constitutive relationship is selected as the mechanical model based on the structural characteristics of REBCO tapes,and suitable microelements are selected to equate the elastic constants using their average stress-strain relationships.Then,a two-dimensional axisymmetric model for coils wound by single-layer tapes is constructed to analyze the dependence of the electric-magnetic-force distribution in the tape on the strain.Finally,the anisotropic approximation of the homogenized bulk method is used to equate large-turn high-field coils,and the electric-magnetic-force distribution characteristics of the coils with/without screening effects and mechanical strain conditions are investigated,respectively.The results reveal that the mechanical strain has a weakening effect on the electromagnetic field distribution of superconducting tapes,but causes a significant enhancement in the force field distribution.In the presence of 0.5% mechanical strain,the maximum weakening of the peak value of the current density and the critical current density inside the high-field coil can reach about 8% and 13%,respectively,with a nearly 5 times increase in the peak stress.The screening current makes the current field distribution inside the coil improve by about 10 times.The screening current induced magnetic field can reach up to 0.8 T,making the relative error of the high-field coil center up to 7.8%.

Cellular Perception: When the Cell Model Includes a Sense Order which Ensues from a Philosophy of Nature, the Signaling and Epigenetics Effects which Can Result from Exposure to Magnetic Fields Are Described Better

Academic biology-medicine refers to a couple of philosophies, Organicism and Mechanism, which translates into an association of Cybernetic diagrams and molecular Reductionism. This association presents logical difficulties which make it unsuitable to describe correctly biological effects of electromagnetic fields, EMF. But these logical difficulties may be overcome when renewing the organic cell idea by means of a Philosophy of Nature which juxtaposes causality order and sense order in the cell. The signalsome, the set of descriptive components resulting from the genome, is constantly reorganized. This remodeling may become epigenetic when the phenotype becomes transformed by experience of perceptions in a given medium, because the perception of overall information coming from the extracellular medium becomes functional within the system. In that cellular perception, it is stated that the significance base which contributes to the sense order results from the qualitative topological structure of the extracellular medium. Therefore the EMF interactions target is not only the membrane and its molecules;it is also the structure of the extracellular medium which bathes the membrane. Knowing that the sense order modulation constitutes the global soil of the (localized) causality order, it is possible to obtain a same EMF bioeffect on a membrane molecule by treating a culture of cells in its bath or by treating only the extracellular aqueous medium. Consequently, the double bioeffect resulting from EMF exposure is described simply, because the sense order, such as it results from the qualitative structuring of the medium, forms the significance base which directs the causal mechanics of the cellular answer.

Theoretical and experimental analyses of continuous casting with soft-contacted mould (Ⅱ)—EMF calculation and experimental analyses

Coupling the quasi 3D numerical simulation of the electromagnetic field and the experiments with some metals, a series of phenomena in the processes of continuous casting with soft contacted mould was analyzed. Some theoretical and experimental models were presented, from which following results were obtained. 1) The electromagnetic force is related with electric conductivity of billet as a power function to 0.4. 2) The heat transfer between billet and mould is related with the contacting pressure, and it is a linear function for tin billet approximately. 3) The distance between initial solidification point and meniscus in billet is related with the surface magnetic flux density as a fourth root function. 4) The temperature gradient in the initial solidifying shell is reduced, which can decrease the tendency of hot tearing on the surface of billet, and increase the equiaxed crystal zone in billet. 5) The stronger the magnetic flux density is, the more shallow and the thinner the oscillation mark on the surface of billet is. 6) The depth of oscillation mark on the billet cast by the soft contacted mould can be reduced to about 10% in comparison with that on the billets cast by traditional mould. 7) In non dimensional condition, the average depth of the oscillation marks on the billets cast by the soft contacted mould decreases with increasing magnetic flux density on there as a complementary error function. [

Theoretical Study of Electromagnetic Wave Propagation: Gaussian Bean Method

In this work, we present the study of electromagnetic wave propagation through a medium with a variable dielectric function using the concept of Gaussian Beam. First of all, we start with wave equation with which we obtain the solution in terms of the electric field and intensity distributions approximate to Gaussian Function, . With this, we analyze the dependency of r on Gaussian beam distribution spread, the distant from the axis at which the intensity of the beam distribution begins to fall at a given estimate of its peak value. The influence of the optimum beam waist wo and the beam spread on the intensity distribution will also be analyzed.

Numerical Modeling and Computer Simulation of a Meander Line Antenna for Alzheimer’s Disease Treatment, a Feasibility Study

Alzheimer’s disease (AD) is a brain disorder that eventually causes memory loss and the ability to perform simple cognitive functions;research efforts within pharmaceuticals and other medical treatments have minimal impact on the disease. Our preliminary biological studies showed that Repeated Electromagnetic Field Stimulation (REFMS) applying an EM frequency of 64 MHz and a specific absorption rate (SAR) of 0.4 - 0.9 W/kg decrease the level of amyloid-β peptides (Aβ), which is the most likely etiology of AD. This study emphasizes uniform E/H field and SAR distribution with adequate penetration depth penetration through multiple human head layers driven with low input power for safety treatments. In this work, we performed numerical modeling and computer simulations of a portable Meander Line antenna (MLA) to achieve the required EMF parameters to treat AD. The MLA device features a low cost, small size, wide bandwidth, and the ability to integrate into a portable system. This study utilized a High-Frequency Simulation System (HFSS) in the design of the MLA with the desired characteristics suited for AD treatment in humans. The team designed a 24-turn antenna with a 60 cm length and 25 cm width and achieved the required resonant frequency of 64 MHz. Here we used two numerical human head phantoms to test the antenna, the MIDA and spherical head phantom with six and seven tissue layers, respectively. The antenna was fed from a 50-Watt input source to obtain the SAR of 0.6 W/kg requirement in the center of the simulated brain tissue layer. We found that the E/H field and SAR distribution produced was not homogeneous;there were areas of high SAR values close to the antenna transmitter, also areas of low SAR value far away from the antenna. This paper details the antenna parameters, the scattering parameters response, the efficiency response, and the E and H field distribution;we presented the computer simulation results and discussed future work for a practical model.

基于合成场强仪的输电工程地面合成电场研究

高压直流(DC)输电线路交叉跨越是我国特高压(UHV)技术发展中出现的问题。由于两回DC线路相互影响,交叉跨越区域内合成电场呈复杂的三维分布,UHV DC输电工程地面合成电场计算较为困难。选取典型±800 kV UHV DC输电工程进行地面合成电场的实测研究。参照GB 39220—2020,采用HDEM-01合成场强仪进行野外现场实测。测量参数为有效期内的场磨传感器上积聚的电荷量。测量结果与运行初期实测数据的对比结果表明:±800 kV换流站周边运行初期合成电场强度略低于后期,且整体水平较低;沿线电磁环境敏感目标运行初期、后期的实测数据中,74%的数值小于5 kV/m。通过此次研究,明确了UHV DC输电工程合成电场不同时期的特性。该研究有助于推进UHV DC输电工程的快速建成,并提高其运行安全性,从而推动电力工程建设的发展。

基于钢锥冲击的煤层卸压方法研究

针对煤矿冲击地压引起的采掘安全问题,以山西晋中左权五里堠煤矿3号煤层开采地质条件为工程背景,提出一种基于钢锥冲击煤层的卸压方法。根据通电线圈间产生电磁互感斥力原理,获得磁力驱动绕线钢锥撞击煤层的冲击力函数式,并结合弹性力学理论,分析冲击力作用下煤体应力场分布特征、裂隙类型、破裂范围及程度。结果表明:(1)冲击力与交流电电压及线圈级数呈正相关关系,与交流电频率及每米线圈匝数呈负相关关系。其中,电压是调控冲击力的最主要因素,综合考虑认为电压取660 V为宜。(2)计算显示钢锥长度与直径仅需1 cm和1.28 cm,与之匹配的2级加速线圈总长为2 cm,可实现冲击装置的微型化,便于在钻孔内灵活布置。(3)冲击力使钻孔横截面围岩出现集中系数为4.0~16.7的叶状极高应力区,其延伸长度为5倍钻孔半径,区内发育张拉裂隙;叶状区之外为集中系数1.7~3.3的高应力区,发育压剪裂隙,其范围可达50倍钻孔半径,据此得到卸压钻孔间距为2.5 m。(4)按卸压段长度,每孔内设置2个间距2 m的冲击装置,冲击力使钻孔纵截面围岩呈现针状极高应力区,相邻针状区间分布椭圆形压剪裂隙区,两者一起贯通2 m厚煤层,实现有效破煤卸压。研究成果为探索基于磁力钢锥冲击的煤层卸压技术奠定初步理论基础。

光电建筑的闪电附着特性及瞬态电磁效应研究

安装在光电建筑顶部的BIPV组件遭受雷击的概率较大。为了保护光电建筑本身和内部敏感电子设备,有必要研究光电建筑的闪电附着特性及雷击电磁效应。首先,搭建光伏组件静电场模型,并通过试验验证了模型的准确性,进而通过仿真计算获得BIPV组件最易遭受雷击的位置。然后,基于光电建筑BIPV组件的闪电附着特性构建雷击瞬态电流和瞬态磁场方程,应用有限元法对光电建筑内部的磁场分布进行仿真计算。最后,将光电建筑内的雷击磁场分布与未安装BIPV组件的普通建筑内雷击磁场分布进行比较,结果表明:BIPV组件金属框架最外层的上边缘接闪率最高;与普通建筑相比,安装了BIPV组件的光电建筑金属框架的雷击瞬态电流分布更均匀,因此光电建筑内部雷击磁场强度安全的区域更大,雷击损害风险更低。

基于二维点缺陷可重构光子晶体的毫米波微等离子体源的研究

本文根据光子晶体缺陷理论,利用HFSS软件设计了一款基于二维可重构光子晶体阵列的毫米波微等离子体源,研究其谐振特性和电磁场分布等。仿真结果表明:晶格数目、介质柱半径和介质柱间距等参数对毫米波微等离子体源的S参数和电磁场分布等有较大影响;当谐振频率为76.02 GHz时,S_(11)为-25.11 dB,品质因数Q为400.11,最大电场强度可以达到2.3×10^(5)V/m。本文工作对基于二维可重构光子晶体的毫米波微等离子体源的进一步研究提供参考。

雷达天线集成避雷针系统的雷电间接效应分析

有源雷达天线集成避雷针系统的雷击瞬态电磁场分布和雷电感应耦合特性是其进行雷击防护的基础。建立集成系统的三维电磁仿真模型,计算分析系统的雷击瞬态电磁场分布特性,发现天线内部雷击瞬态电磁场在靠近内表面部分相对较大,之后向中心部分快速衰减,天线阵面采用网状结构比采用栅格结构的电磁场屏蔽效果约强2个数量级。进一步通过开展实型天线集成避雷针系统模拟雷击试验,获取了天线系统内部不同端口的感应电压,结果显示,在天线上电状态下内部线缆的感应电压较不上电状态时高,当线缆紧贴天线舱内壁时,其感应电压较悬空布线时的感应电压分别降低了48.1%、68.9%和90.7%。本文取得的相关结果可为有源雷达天线集成避雷针系统的雷电电磁防护设计提供参考。