• Title/Summary/Keyword: Working Range

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Effects of Working Fluid Filling Ration and Heat Flux on Correlations of Heat Transfer Coefficient in Loop Thermosyphon

  • Chang, Ki-Chang;Lee, Young-Soo
    • International Journal of Air-Conditioning and Refrigeration
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    • v.10 no.3
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    • pp.153-161
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    • 2002
  • Due to the coupling between momentum and energy transport theoretical analysis of the loop performance is very complicate, therefore it is necessary that these problems be solved by experimental investigation before applying the loop thermosyphon to heat exchanger de-sign. The evaporator and condenser of the loop thermosyphon were made of carbon-steel, and distilled water was used as working fluid in the experiments. From the experimental data correlations of heat transfer coefficient for evaporator and condenser sections were obtained. For heat fluxes in the range of 13000~78000 W/$m^2$, the correlation equations of heat transfer coefficients in evaporator and condenser predict the experimental behavior to within $\pm$5% and $\pm$20% respectively.

A Study on the Design of Rural Kitchen Furniture (농촌생활에 적합한 부엌가구 디자인요소와 모델 계획연구)

  • Yoon, Bok-Cha;Chi, Soon;Yoon, Chung-Sook;Park, Eun-Seon;Lee, Eun-Kyung;Kim, Hee-Jung
    • Korean Institute of Interior Design Journal
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    • no.2
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    • pp.29-39
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    • 1994
  • The purpose of this study was to design rural kitchen furnitures. Thirty seven rural houses were selected for this study. Present and past uses of space for cooling and dining were investigated by a field survey method. The Major findings were that ; 1) Sink, mixing, and range centers should be installed in rural kitchen 2) The depth of working center, 550-600mm was recommended. And working space cold be added by 150mm in depth and 100mm in height. The height of working center, 820mm-850mm was recommended . The minimum width of sink was 900 mm and the optimum one was 1200mm. The optimum width of mixing center and cooking center were 600m respectively 3) In the low ceiling of kitchen or the wooden structure of kitchen, a wall cabinet without upper cupboard was recommended. On the basis of the results, four types of rural kitchen furnitures is proposed.

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Influence of Working Conditions on the Spinnability of Cylindrical Cups of Aluminum Sheet Metal (알루미늄 원통컵의 스피닝 성형성에 영향미치는 작업조건 연구)

  • 김종호;박규호;나경환;김승수
    • Transactions of Materials Processing
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    • v.8 no.5
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    • pp.465-470
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    • 1999
  • Many researchers have, nowadays, studied on spinning which can produce highly qualified products by CNC spinning machine equipped with hydraulic devices. The products have continuous metal flow which improves fatigue life, yield point, tensile strength and hardness. This study is to investigate the influence of various working conditions on the spinnability of cylindrical cups such as feed rate(ν), feed pitch(p), angle of roller holder(α), and the inclination angle of first roller path. Through experiments the feed rate of (0.4∼0.7) mm/rev was shown to give the drawing ratio of 2.5 when the angle of roller holder was 5°, However, by increasing the angle of roller holder from 5°to 20°, the range of feed rate which can produce deeper cups became wider and the spinnability was also improved. The optimum working conditions, for the maximum formability of aluminum sheet metal as well as dimensional accuracy of spun cups, are presented and discussed.

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Influence of Working Pressure on The Magnetic Properties of Tb(Fe0.55Co0.45)1.5 Thin Films

  • Tu, Le Tuan;Duc, Nguyen Huu;Jeong, Jong-Ryul;Kim, Cheol-Gi
    • Journal of Magnetics
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    • v.13 no.4
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    • pp.160-162
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    • 2008
  • In this work the magnetic anisotropies of magnetostriction material $Tb(Fe_{0.55}Co_{0.45})_{1.5}$ (named a-TerfecoHan) films were investigated with respect to working pressures in the range 1-7 mTorr. The results obtained show that perpendicular magnetic anisotropy (PMA) can be obtained at a working pressure above 5.1 mTorr. XRD was utilized to clarify the origin of the PMA observed in $Tb(Fe_{0.55}Co_{0.45})_{1.5}$ films, and revealed that all samples were amorphous. Therefore, we propose that the PMA effect is explained by stress produced in film due to internal relaxation process and magnetic anisotropy enhancements caused by magnetoelastic interactions.

Effects of Working Fluid Filling Ratio and Heat flux on Correlations of Heat Transfer Coefficient in Loop Thermosyphon (루프 써모사이폰에서 작동유체 충액률과 열유속이 열전달계수의 상관식에 미치는 영향)

  • 장기창;이기우;이영수;유성연
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.6
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    • pp.462-473
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    • 2001
  • Due to the coupling between momentum and energy transport theoretical analysis of the loop performance is very complicate, therefore it is necessary that these problems be solved by experimental investigation before applying th loop thermosyphon to heat exchanger design. The evaporator and condenser of the loop thermosyphon were made of carbon-steel, and distilled water was used as working fluid in the experiments. From the experimental data correlations of heat transfer coefficient for evaporator and condenser sections were obtained. For heat fluxes in th range of 13~78kW/$m^2$, the correlation equations of heat transfer coefficients in evaporator and condenser predict the experimental behavior to within $\p$\pm$5% and\;\pm20$% respectively.

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Design of Exo-Suit for Shoulder Muscle Strength Support (어깨 근력보조를 위한 엑소수트 설계)

  • Kwang-Woo Jeon;TaeHwan Kim;SeungWoo Kim;JungJun Kim;Hyun-Joon Chung
    • The Journal of Korea Robotics Society
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    • v.18 no.1
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    • pp.110-116
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    • 2023
  • In this study describes the design of Exo-suit to assist those who work in unstructured positions. The present study aimed to analyze various types of work, especially those performed in unstructured postures by heavy industry workers. Based on the motion capture analysis results, an attempt was made to develop a shoulder muscle-assistive Exo-suit capable of assisting a wearer who is working using shoulder muscles. In the present study, as the first step of developing a shoulder muscle-assistive Exo-suit, different working scenarios were simulated, and the corresponding motion data were estimated using motion capture devices. The obtained motion data were reflected in the design of the Exo-suit. The main structure of the shoulder muscle-assistive Exo-suit was made of a carbon fiber-reinforced composite to obtain the weight reduction. The shoulder muscle assistive Exo-suit was designed to fully cover the range of motion for workers working in unstructured postures.

High precision tracking contorl algorithm for micro electrostatic actuator with nonlinearity (Nonlinearity를 갖는 Micro Electorstatic Actuator의 초정밀 추종제어)

  • 김경한;최현택;송재욱;정완균
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.464-467
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    • 1997
  • In this paper, a high precision track following control algorithm is proposed for micro electrostatic actuator considering of the application for hard disk drive. The micro electrostatic actuator proposed has nonlinear voltage-displacement characteristic in a working range of 0.8.mu.m and has uni-directional movement. Mid range reference and open-loop bias are proposed for the revision of negative position error, and inverse model for linearization.

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HARMONICS OF INDUSTRIAL POWER ELECTRONIC CONVERTERS IN THE EREQUENCY RANGE UP TO 10 KHZ

  • Buttner, J.;Krechla, A.;Petzoldt, J.;Machost, D.
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.598-602
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    • 1998
  • This paper refers to fundamental investigations and simulations of conducted electromagnetic inference emissions produced by power electronic devices in a frequency range from 2 to 10 kHz. The emissions of different industrial power converters were measured and compared. The influence of different working conditions over the altitude of the EMI are represented. Simulations of the power converter system including the line impedance stabilisation network certify the measurements.

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The Study on Selection of human Model for Controllability Evaluation According to Working Postures

  • Kim, Do-Hoon;Park, Sung-Joon;Lim, Young-Jae;Jung, Eui-S.
    • Journal of the Ergonomics Society of Korea
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    • v.31 no.3
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    • pp.437-444
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    • 2012
  • The purpose of this study was to suggest appropriate human model for ergonomic evaluation considering working postures on 3D space. Background: Traditionally extreme design rules have been widely utilized at the stage of designing products. Body size of 5th percentile and 95th percentile in stature has been generally selected for controllability and clearance evaluation, respectively. However, these rules had limitations in reflecting working posture in ergonomic evaluation. Method: In order to define working posture on 3D space, not only sagittal plane but also lateral plane was considered. Kinematic linkage body model was utilized for representation of working posture. By utilizing the anthropometric data of 2,836 South Korean male populations, the point cloud for end points of linkage models was derived. The individuals who were lacking in certain controllability were selected as human models for the evaluation. Result: In case of standing posture it was found that conventional approach is proper for all controllability evaluations. Contrary to standing posture, tall people had less controllability on control location below shoulder point in sitting posture. Conclusion: From the derived proper range on controllability, ergonomic evaluation rule was suggested according to working posture especially in standing and sitting. Application: The results of the study are expected to aid in selection of appropriate human model for ergonomic evaluation and to improve the usability of products and work space.

Supply and demand of nursing manpower for small and medium hospitals in rural area: nursing shortage versus wage disparity (중소병원의 간호인력 수급 논쟁: 인력난 vs 임금난)

  • Park, Kwang-Ok
    • Perspectives in Nursing Science
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    • v.6 no.1
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    • pp.67-76
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    • 2009
  • Recently, small and medium-sized hospitals which are located in rural areas have many difficulties in securing high quality nurses. That is because working environments for nurses in small and medium-sized hospitals in rural areas are poor compared with those of big hospitals in urban. As a result, the migration of nurses from small and medium-sized hospitals in rural areas to big hospitals in urban is continuously happening. In general, big hospitals provide nurses with high level of salary and fringe benefits. To prevent the migration of nurses, chief executive officers of small & medium hospitals in rural areas have been interested in improving nurses' working conditions including wages. Also, they have raised nurses' salary and improved working conditions. But, basically these individualized efforts have some limit. In connection with this, medical interest groups have produced various voices in terms of interpretation and solutions for these issues. However, from the future perspectives, it seems evident that two approaches for both manpower supply and demand plans of nurses are necessary. They should contain not only accurate estimation of the supply-demand of nursing manpower but also the improvement of working conditions and wages of nurses. Estimation of nursing manpower supply-demand depends on the standards and criteria being used. Supply and demand may be met or not in accordance with the points emphasized on the decision. In the articles, issues regarding nursing manpower, levels of salary, other working conditions and social support system for child care are discussed. According to Joe's report (2005), most health institutions did not meet the guidelines of nurse staffing in Medical Law. The wages of nurse vary on every hospital and there is a big difference in wages' range. The average starting salary for a nurse is 22 million won a year. In case of tertiary hospitals, it reaches up to 30 million won a year. Nurse as a profession should have a strong responsibility and should take care of the patients for 24 hours with three working shifts. Also, most of them are female who have the burden of child rearing. Therefore, it is suggested to increase the salary, to provide comfortable working conditions, and to have social support system for nurses with household affairs.

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