NOVEL ELECTRIC FIELD EXPOSURE CONTROL METHODS FOR MULTI-STORY BUILDINGS INSTALLED IN VICINITY OF HIGH-VOLTAGE APPARATUS USING FEM

Facilities and buildings installed nearby high voltage equipment and electric field exposure is always a serious threat to the health of organisms and can have a significant impact on the functioning of sensitive and vital organs such as the heart and brain. Therefore, it is necessary to study the electromagnetic field value in these areas to control the intensity and restrict the induced value regarding to international recommendations. In this paper, the effects of 230KV transmission line electric fields on the environment are examined by proper FEM software.The model under consideration in this project is a four story building adjacent to the 230KV transmission line.At first, the distance between the building and high voltage transmission lines and its relationship to the intensity of the electric field is examined, and then the intensity of the electric field is compared to the standards of the International Commission on Non Ionizing Radiation Protection (ICNIRP). To continue, in places where the electric field exceeds the standard level value, solutions to reduce the intensity of the electric field to the tolerable value have been proposed.The first solution is to use a metal shield around the building as a Faraday cage, which weakens the potential for electric field value by creating an enclosed surface, the reduction rate is 4700%,both complete cage shape and incomplete cage shapes are considered in this study which reduces the exposure value to 62.5% of its initial value. The second approach to reducing the electric field is to use protective conductor paints against electromagnetic fields. In the following study, the effect of using trees as a barrier against electromagnetic radiation will be examined. Finally, the three proposed solutions are compared in terms of environmental constraints, economic justification, and the reduction in electric field value.

Prediction of Electromagnetic Characteristics in Stator End Parts of a Turbo-Generator Based on MLP and SVR

In order to study the multiple restricted factors and parameters of the eddy current loss of generator end structures, both the multi-layer perceptron (MLP) and support vector regression (SVR) are used to study and predict the mechanism of the synergistic effect of metal shield conductivity, relative permeability of clamping plates and structural characteristics of eddy current losses. Based on the eddy current losses of generator end structures under different metal shielding thicknesses and electromagnetic properties, the calculation accuracy of the MLP and SVR is compared. The prediction method gives an effective means for the complex design of the end region of the generator, which reduces the effort of the designers. It also promotes the design efficiency of the electrical generator.

Experimental and Numerical Investigation on the Perforation Resistance of Double-Layered Metal Shield under High-Velocity Impact of Armor-Piercing Projectiles

In the case of protection of transportation systems, the optimization of the shield is of practical interest to reduce the weight of such components and thus increase the payload or reduce the fuel consumption. As far as metal shields are concerned, some investigations based on numerical simulations showed that a multi-layered configuration made of layers of different metals could be a promising solution to reduce the weight of the shield. However, only a few experimental studies on this subject are available. The aim of this study is therefore to discuss whether or not a monolithic shield can be substituted by a double-layered configuration manufactured from two different metals and if such a configuration can guarantee the same perforation resistance at a lower weight. In order to answer this question, the performance of a ballistic shield constituted of a layer of high-strength steel and a layer of an aluminum alloy impacted by an armor piercing projectile was investigated in experimental tests. Furthermore, an axisymmetric finite element model was developed. The effect of the strain rate hardening parameter C and the thermal softening parameter m of the Johnson–Cook constitutive model was investigated. The numerical model was used to understand the perforation process and the energy dissipation mechanism inside the target. It was found that if the high-strength steel plate is used as a front layer, the specific ballistic energy increases by 54% with respect to the monolithic high-strength steel plate. On the other hand, the specific ballistic energy decreases if the aluminum plate is used as the front layer.

Broadband Metal-Dielectric Waveguide Path with Low Losses in the EHF Range

. The present paper is devoted to the design of a new shielded metal-dielectric waveguide with low losses (less than 0.5 dB/m) and wide bandwidth for the 90–100 GHz frequency range. Various types of waveguide structures were analyzed, such as metal waveguides, oversized metal waveguides, dielectric waveguides, dielectric waveguides with a metal shield and various designs of the dielectric filling element. Estimates of loss per unit length in them are obtained. The design of a waveguide containing an oversized round metal screen and a dielectric element consisting of a plate and a rod, located in the center of symmetry of the device, is proposed. The task of creating a transition from the investigated waveguide to a standard rectangular metal waveguide is considered. It is a horn transition from a circular cross-section to a rectangular one with a length of more than 25 wavelengths with a dielectric structure continuing the dielectric element of the waveguide path. As a result of the work, the ratios of the dimensions of the structural elements of the waveguide path and the materials used were obtained that satisfy the required losses.

The development of the “Storm Tracker” and its applications for atmospheric high-resolution upper-air observations

In this study, we introduce a newly developed upper-air observational instrument for atmospheric research. The “Storm Tracker” is an ultra-lightweight (about 20 g including battery), multi-channel simultaneous capable radiosonde designed by the Department of Atmospheric Sciences at National Taiwan University. Developed in 2016, the Storm Tracker aims to provide an alternative for observing atmospheric vertical profiles with a high temporal resolution, especially the lower-level atmosphere under severe weather conditions such as extreme thunderstorms and tropical cyclones. Field experiments were conducted as trial runs in Wu-Chi, Taichung, Taiwan, to examine the ability of the Storm Tracker to observe the boundary layer, in addition to the intercomparison between the Storm Tracker and the widely used Vaisala RS41-SGP radiosonde. Among the co-launches of the Storm Tracker and Vaisala RS41 radiosondes, the measurements of pressure, wind speed, and wind direction are highly consistent between the measurements of the Storm Tracker and the Vaisala RS41-SGP. However, a significant daytime warm bias in the Storm Tracker was found due to solar heating. A metal shield specifically for the Storm Tracker was thus installed and showed mitigation for the warm biases and the overall variance. With the much lower costs of the radiosondes and the simultaneous multi-channel receiver, the Storm Tracker system has shown great potential for high-frequency observational needs in atmospheric research.

The Development of the Storm Tracker and its Applications for Atmospheric High-resolution Upper-air Observations

In this study, we introduce a newly-developed upper-air observational instrument for atmospheric research. The Storm Tracker (or NTU mini-Radiosonde), is an ultra-lightweight (about 20 g including battery), multi-channel simultaneous capable radiosonde designed by the Department of Atmospheric Sciences at National Taiwan University. Developed since 2016, the Storm Tracker aims to provide an alternative for observation of atmospheric vertical profiles with a high temporal resolution, especially lower-level atmosphere under severe weather such as extreme thunderstorms and tropical cyclones. Two field experiments were conducted as trial runs in December 2017 and July 2018 at Wu-Chi, Taichung, Taiwan, to compare the Strom Tracker with the widely used Vaisala RS41 radiosonde. Among 53 co-launches of the Storm Tracker and Vaisala RS41 radiosondes, the raw measurements of pressure, wind speed, and wind direction are highly consistent between the Strom Tracker and Vaisala RS41. However, a significant daytime warm bias was found due to solar heating. A metal shield specifically for the Storm Tracker was thus installed and shows good mitigation for the warm biases. With the much lower costs of the sondes and the simultaneous multi-channel receiver, the Storm Tracker system has been proved to be beneficial for high-frequency observational needs in atmospheric research.

Screens for Protection Against Electromagnetic Radiation

This paper presents the ways to protect workers against the electromagnetic fields in the radio frequency range up to one centimeter using a shielding method. The study focuses on the protective shields for absorbing that are produced from pure sheet metal using carbon filler between the metal sheets. There are compared their characteristics at the frequency range up to one centimeter that were obtained by calculations, modeling and experimental methods. Here are provided calculation formulas, results from computer modeling, experimental results from the metal shield itself and the shield with the carbon black filler. The results are presented in graphs. Comparison analysis of the absorption characteristics was done using a method that measured a signal that was reflected from the shield..

A study on an electromagnetic shield with carbon filler

This article presents protective properties of an electromagnetic metal shield with the carbon black filler, as well compares its characteristics with ones that regular metal protective shield has. There are three methods to compare, namely the first is calculation, next one is simulation in CST software, and finally are experimental methods. The study results obtained with all three methods are the same. Therefore, after multiple comparison of the results obtained with two types of shields, we can say that the electromagnetic shield with the carbon filler has better shielding characteristics.