• Title/Summary/Keyword: uniform current

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Non-Uniform Current Distribution of Multi-Strand HTS Cable (Multi-Strand HTS 케이블에서의 전류 불균일 분포)

  • Bae, Joon-Han;Bae, Duck-Kweon;Cho, Jeon-Wook;Sim, Ki-Deok;Kim, Hae-Jong;Seong, Ki-Chul;Ko, Tae-Kuk
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.10a
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    • pp.254-259
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    • 2003
  • The 4-probe method with a voltage tap on terminals has been used for the measurement of the critical current of multi-strand high-Tc superconducting (HTS) cables. And the critical current of cables is obtained as the measured total current divided by the number of conductor when the terminal voltage exceeds the predetermined criterion of critical current. However, because of the non-uniform current distribution due to the different critical current, shapes, and other characteristics of each conductor this is not applicable method to the multi-strand HTS cable. To determine the critical current of multi-strand HTS cable the critical current of each conductor must be measured with different method. In this paper, the current distribution and the critical current of each conductor in multi-strand cable were measured with specially made pick-up coils and voltage taps. It is presented that the real critical current of multi-strand is smaller than sum of each conductors. The main cause of non-uniform current distribution is the different resistances appeared in each HTS wires.

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The effect of non-uniform current distribution on transport current loss in stacked high-Tc superconductor tapes

  • Choi, Se-Yong;Nah, Wan-Soo;Joo, Jin-Ho;Ryu, Kyung-Woo;Lee, Byoung-Seob;Yoon, Jang-Hee;Ok, Jung-Woo;Park, Jin-Yong;Won, Mi-Sook
    • Progress in Superconductivity and Cryogenics
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    • v.14 no.2
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    • pp.16-19
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    • 2012
  • The influence of current distribution on the transport current loss in vertically stacked high-$T_c$ superconductor (HTS) tapes was evaluated. AC loss was analyzed as a function of current distribution by introducing a current distribution parameter through a numerical method (finite element analysis). AC loss under non-uniform current distribution is always higher than that for a uniformly distributed transport current in a conductor. Although the effect of non-uniformity is relatively insignificant in low transport current, AC loss increases substantially in high transport current regions as non-uniformity is enlarged. The results verify that non-uniform current distribution causes extra loss by examining the cross-sectional view of current densities in stacked conductor.

A Study on the Taekwondo Uniform (태권도복에 관한 연구(제1보) -태권도복의 착용실태를 중심으로-)

  • 김숙진
    • Journal of the Korean Home Economics Association
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    • v.25 no.4
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    • pp.19-32
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    • 1987
  • The purpose of this study was to provide basis data for the pattern and material development of the Taekondo uniform by investigating the Taekwondo uniform wearing status of 260 Taekwondo players. The results can be summarized as follows: 1. In the current material of Taekwondo uniform, the problem of physiological comfort was generally dissatisfied in all subjects. And this unsatisfactory trend was founded higher in female player. 2. In the problem of the body fitness of Taekwondo unifrom, the unifitness of upper and lower clothes was founded higher in female player. And both of male and female player represented unfitness more high in lower clothes. So the current size of Taekwondo uniform, especially the size of lower clothes had its problem. 3. The problem of the sports function, the body fitness and easiness of wearing of Taekwondo uniform was generally founded uncomfortable in all subjects. But especially female player, fat type player was founded higher in the phase of discomfort. And accoring to the method of gaining clothes, the case of the slop was founded the highest.

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Influence of the Density Gradient on the Current of the Electrode Immersed in the Non-uniform Plasma (플라즈마 삽입전극의 전류에 미치는 밀도 구배의 영향)

  • Hwang, Hui-Dong;Gu, Chi-Wuk;Chung, Kyung-Jae;Choe, Jae-Myung;Kim, Gon-Ho;Ko, Kwang-Cheol
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.6
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    • pp.504-509
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    • 2011
  • The conducting current of non-uniform plasma immersed electrode consists of ion current and secondary electron emission current caused by the impinging ion current. The ion current is determined by the ion dose passing through the sheath in front of electrode and the ion distribution in front of the electrode plays an important role in the secondary electron emission. The investigation of the distributed plasma and secondary electron effect on electrode ion current was carried out as the stainless steel electrode plugged with quartz tube was immersed in the inductively coupled Ar plasma using the antenna powered by 1 kw and the density profile was measured. After that, the negative voltage was applied by 1 kV~6 kV to measure the conduction current for the analysis of ion current.

A method for uniform current distribution of HTS cable using Inter-Phase Transformers (Inter-Phase Transformers를 이용한 고온초전도 케이블의 층간 전류 등분배 방안)

  • Choi, Yong-Sun;Yim, Seong-Woo;Sim, Jung-Wook;Hwang, Si-Dole;Park, In-Gyu
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.973-975
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    • 2003
  • Uniform current distribution among conductor layers in HTS cables using IPTS (inter-phase transformers) was proposed. Conventional methods for current distribution, in which resistors are inserted to conductor layers, causes additional loss. In contrast, IPTS, which use magnetic coupling, make it possible that the current in parallel circuits is distributed uniformly with any load, and minimize the loss. In this study, IPTS were designed and fabricated for examination of uniform current distribution in the conductor layers of HTS cables. The ITP was designed through calculation of its impedance that can cancel the inductance of the conduction layers.

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Evaluation of High Order Statistical Parameter for Electrochemical Noise Analysis

  • Kim, Jong Jip
    • Corrosion Science and Technology
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    • v.7 no.5
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    • pp.296-299
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    • 2008
  • High order statistical parameters were evaluated using the electrochemical noise data collected during corrosion of type 430 stainless steel coupled to a inert, platinum electrode in 3.5% NaCl solution. High order statistical parameters are shown to predict uniform corrosion properly. However, Localization index, skewness of current, kurtosis and skewness of potential are capable of predicting pitting corrosion only when the transients are large with long life time. Of the high order statistical parameters evaluated, kurtosis of current is found to be the most sensitive parameter for detecting uniform and pitting corrosion.

Design of flow path with 2 inlet and outlets to improve cell performance and prevent cell degradation in Solid Oxide Fuel Cell (SOFC 셀 성능 향상 및 수명 저하 방지를 위한 입구와 출구 2개의 유로 설계)

  • Kim, Dongwoo;Yeom, Eunseop
    • Journal of the Korean Society of Visualization
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    • v.19 no.2
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    • pp.56-62
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    • 2021
  • Solid oxide fuel cells (SOFCs) is the high efficiency fuel cell operating at high temperatures ranging from 700-1000℃. Design of the flow paths of the fuel and air in SOFCs is important to improve cell performance and prevent cell degradation. However, the uneven distribution of current density in the traditional type having one inlet and outlet causes cell degradation. In this regard, the parallel flow path with two inlet and outlets was designed and compared to the traditional type based on computational fluid dynamics (CFD) simulation. To check the cell performance, hydrogen distribution, velocity distribution and current density distribution were monitored. The results validated that the parallel designs with two inlets and outlets have a higher cell performance compared to the traditional design with one inlet and outlet due to a larger reaction area. In case of uniform-type paths, more uniform current density distribution was observed with less cross-sectional variation in flow paths. In case of contracted and expanded inflow paths, significant improvement of performance and uniform current density was not observed compared to uniform parallel path. Considering SOFC cell with uniform current density can prevent cell degradation, more suitable design of SOFC cell with less cross-sectional variation in the flow path should be developed. This work can be helpful to understand the role of flow distribution in the SOFC performance.

The Evaluation of Movement Functionality on Improved Pattern-Design Working Uniform of Construction Site Worker (건설현장 작업복의 패턴디자인 개선에 따른 동작기능성 평가)

  • Kim, Seong-Suk;Kim, Hee-Eun
    • Fashion & Textile Research Journal
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    • v.9 no.2
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    • pp.237-242
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    • 2007
  • The purpose of this study is to examine the functionality with improved pattern-design working uniform(protocol, P) and current working uniform(control, C). Movement functionality evaluation of improved pattern-design working uniform was carried out through sensory evaluation of working uniform. Movements for the sensory evaluation consisted of four types of up and down and horizontal movements of the shoulders, four types of waist movements and five types of knee movements. The results have been shown as follows: The sensory value of back girth, wrist, side seam area of the "P" with the posture of raising an arm forward up to $90^{\circ}$ and the maximal arm's vertical movement significantly improved compared to the "C". Therefore, it can be concluded that movement functionality was increased with the improved pattern-design working uniform in the respect of arm's up and down movement. Furthermore, for P, Movement functionality improvements were shown in P with arm's horizontal movement, waist bending movement, and knee movement. Current working uniform(C) is jumper-type which wa designed without consideration for movement functionality of the arms and legs. But Pattern-design uniform(P) which was developed in this study. Therefore, the more patterns development, the better movement functionality in working uniform. The improved movement functionality improvements in working uniform will provide not only personal pleasantness but also efficiency of productivity at construction sites. In respect of human body's movement, further study for improved working uniform is required.

A research on the preferred design of nurse uniform in the general hospital in China and the development of nurse uniform (중국 종합병원 간호사복의 선호디자인 조사와 간호사복 개발 연구)

  • Jin, Xuanyi;Lee, Sojung;Kim, Dong-Eun
    • The Research Journal of the Costume Culture
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    • v.29 no.6
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    • pp.747-762
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    • 2021
  • The purpose of this study was to examine the current satisfaction levels with nurse uniforms at Taizhou General Hospital in China and to find areas for improvement in order to develop nurse uniforms with improved comfort, fit and convenience. To investigate satisfaction with nurse uniforms, a survey was conducted of 150 nurses. The general characteristics of the nurses, uniform conditions, feelings of satisfaction, fit, preferred designs, inconvenient aspects of the uniforms, and areas for improvement were analyzed. Eight materials of cotton/polyester blended fabrics were selected according to Chinese nurse uniform regulations, and the physical properties of the materials were tested along with the materials used in current nurse uniforms. Four new nurse uniforms with increased aesthetics, functionality, and comfort were developed based on the survey results. Materials with excellent absorption, moisture permeability, and ventilation were used as main fabrics. According to the preferred designs of nurses at Taizhou City General Hospital, China, 4 types of nurse uniforms designed, consisting of design 1 (shirt and pants), design 2 (shirt and pants), design 3 (dress), and design 4 (shirt and skirt). The new nurse uniforms offered better functionality with an improved fit at the armpits, waist, hips, and knees based on product measurements.