• 제목/요약/키워드: Cold draft

검색결과 24건 처리시간 0.031초

롤갭 시뮬레이터의 개발과 패스스케쥴 개선 (Development of Rollgap Simulator and Its Application to Draft Schedule Adjustment)

  • 안재환;이영호;이인우
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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    • pp.163-172
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    • 2004
  • A fast, accurate model for calculating roll gap variables are critical to the implementation of computer based automation systems for cold rolling mills. Based on the work of Fleck and Johnson, rollgap simulator with non-circular arc model was developed using the influence function. This developed model is capable of predicting values of force, torque and slip which can be applied over the wide range of rolling conditions including cold rolling/DR/temper mill with high execution speed. Friction coefficient was obtained as a function of operation conditions through analyzing measured data. After combination of rollgap simulator with production strategy, draft schedule for No.3 RCM (Reversible Cold Rolling Mill) in Incheon works of Dongbu Steel was developed. This draft schedule will be installed in the setup computer of No.3 RCM replacing old Hitachi model.

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급기구 형상에 따른 겨울철 실내 온열환경의 비교 (Comparison of Indoor Thermal Environments in Winter depending on Supply Vent Configurations)

  • 한화택;정영균
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2008년도 하계학술발표대회 논문집
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    • pp.970-975
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    • 2008
  • This study considers indoor thermal comfort in an ondol space by supply vent configurations to prevent cold draft in winter. A specially-designed vent cap has been investigated in comparison with a round pan-type vent and a simple opening without a cap. Numerical simulations have been conducted using CFD to analyze thermal comfort indices such as Predicted Mean Vote (PMV) and Effective Draft Temperature (EDT) as well as air distribution index i.e. Air Diffusion Performance Index (ADPI). Results show the new vent cap provides improved thermal comfort conditions especially near ondol heated floor, as the cold outdoor air spreads upwards along the vertical wall before reaching occupant region near floor. This paper includes discussions on the flow and comfort distributions created by the thermal jets from the vents.

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공동주택용 하이브리드 환기설비에 관한 연구 (A Study of Hybrid Ventilation System applying to an Apartment House)

  • 이성환
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2006년도 하계학술발표대회 논문집
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    • pp.1137-1143
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    • 2006
  • The purpose of this research lays on examining the adequacy of the hybrid ventilation system. The hybrid ventilation system must satisfy the next to be used. Firstly, the cold-draft phenomenon must not exist in the occupied zone. Secondly, the condensation must not happen on the surfaces of vents. Thirdly, the flow of make-up air must be happened in an each space by exhausted air of a rest room and living room. We used an examination and CFD method to verify these. Trough the examination of air-vents, We confirmed that the cold-draft to be induced by make-up air does not happen and could not find the condensation in the limits of outdoor temperature higher than 265K. Through CFD simulation, We confirmed that the rapid temperature change existed only within 0.5m the occupied zone and the flow of air was happened in an each space by only exhausted air in the rest room and living room. Consequently, the hybrid system is possible method to an apartment house.

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실내 기류의 수치해석 (Numerical method for Thermal Convection of air in Ondol Room)

  • 민만기;김주균
    • 대한설비공학회지:설비저널
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    • 제7권1호
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    • pp.4-12
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    • 1978
  • At Grashof numbers $10^{10},\;5{\times}10^{10}$, and $10^{11}$ nonlinear partial differential equations for two dimensional thermal circulation of air in a rectangular enclosure heated from below are solved numerically by finite difference explicit methood in time-dependent form. Two vertical walls and ceiling are held at low temperature and floor at high temperture. Results are compared with From's numerical solutions at $10^9{\lesssim}\;N_{Gr}\;<10^{13}$. The effective draft temperature fields are also obtained to examine cold draft problem, there included a line of constant effective draft temperature $-1.667^{\circ}C$ which is essentially Houghten's $80\%$ comfort data.

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천장형 유닛을 설치한 교실 내의 인체 주변 온열환경에 관한 실측연구 (A Field Measuring Study on the Thermal Environment of Human Surrounding in the Classroom Equipped with Ceiling Unit)

  • 조성우;임영빈;이경희
    • 설비공학논문집
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    • 제18권3호
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    • pp.240-246
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    • 2006
  • This paper performed to investigate on vertical temperature distribution, effective draft temperature (ETD) and PMV (Predicted Mean Vote) in the classroom, which is located YangSan city (Kyungsangnam-Do), Korea, is equipped with ceiling unit. The vertical temperature difference between F.L+10 cm (ankle) and F.L+120 cm (neck) of a measuring point which is adjacent corridor in the classroom showed about $1^{\circ}C$ but of measuring point which is adjacent outdoor expressed up to $4^{\circ}C$, The effective draft temperature (ETD) is -2.3 and -0.52 and 0.67 at near ceiling unit but is 1.2 and 3.3 at far from ceiling unit. The PMV of total classroom showed the range of 'Cold' and 'Slightly Cold.' Therefore, to achieve comfort condition in the classroom is equipped with ceiling unit, the location of ceiling unit and discharge angle and discharge distance from ceiling unit are very important elements.

천연 복합유기화합물인 부식질을 분해하는 남극 툰드라 토양 Pseudomonas sp. PAMC 29040의 유전체 분석 (Draft genome sequence of humic substance-degrading Pseudomonas sp. PAMC 29040 from Antarctic tundra soil)

  • 김덕규;이형석
    • 미생물학회지
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    • 제55권1호
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    • pp.83-85
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    • 2019
  • 남극 연안 툰드라 토양에서 리그닌 분해능이 있는 Pseudomonas sp. PAMC 29040를 분리하였으며, 이후 토양 유기물의 주요 구성성분인 복합유기화합물 부식질 분해능을 확인하였다. 부식질 초기 저분자화 효소(예, dye-decolorizing peroxidase)와 부식질 유래의 다양한 저분자 분해산물들을 분해하는 효소들(예, vanillate O-demethylase)를 탐색하기 위해 PAMC 29040 게놈 염기서열을 분석하였다. 분석을 통해서 최종 확보한 효소유전자 정보는 저온환경에 서식하는 토양 세균의 부식질 분해경로 제안에 활용될 것이다.

한국의 산후 문화와 여성이 경험한 산후병에 관한 일상생활기술적 연구 (An Ethnographic Study of Sanhubyung experienced by Women in Korean Postpartal Culture)

  • 유은광
    • 대한간호학회지
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    • 제25권4호
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    • pp.825-836
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    • 1995
  • This ethnogrphic exploratory study sought to de-fine the meaning of Sanhubyung, as consequence from the perspective of the women who experienced it. A convenience sample of 9 elderly women in San Francisco. and 20 postpartal women and their 20 non-professional helpers during postpartum in Seoul, Korea were observed and interviewed for 23 months from January 1991 to December 1992 at the Human Development Center in San Francisco and at the hospital and their homes in Seoul, Korea. Sanhubyung was regarded as the consequence of "Doing a Sanhujori Wrongly," as a group of symptoms or sequelae which have two types of characteristics of symptoms . chronic and acute. It can be called a culture bound syndrome in the cultural context re-lated to childbearing phenomenon in Korea. If women violate the principles of Sanhujori, such symptoms can appear at various times : during the period of postpartum itself, at any time, periodically, especially at the anniversary of the child's birth, late forties, and in old age. Acute symptoms that can be classified into immediate and late types include painful and edematous gingiva, sensitive teeth, strange sensation and pain in the knees or backache. Besides, there is a localized sense of soreness and pain ; sense of being in a draft and cold, stomach upset, GI irritation, chilling, shivering, and tiredness, pain and dazzling in the eyes. Chronic symptoms occur in the head, neck, teeth, back, hands, knees, hands and feet, arms and legs, eyes, sinews and joints, bones, and in the body or as a whole. Generally these symptoms are pain, often accompanying a feeling of being cold and in a draft, regardless of actual weather conditions. In conclusion, this findings reflect the Oriental way of thought of causal relationship of women's health and illness based on the wholistic paradigm of harmony and balance of two forces, Yin(cold) -Yang(hot). It provides a challenge to the professional sector to rethink the effect of culture on health and illness. Finally, it suggests care providers use cultural assessment for the appropriateness of the intervention and quality of care for desirable health outcomes.

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공동주택의 지하주차장 연결통로 및 엘리베이터 홀의 환기에 관한 실험적 연구 (An Experimental Study on Ventilation of Connection Passage and Elevator Hall of Underground Parking in the Apartment Houses)

  • 김일겸;박우철
    • 한국산학기술학회논문지
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    • 제9권6호
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    • pp.1523-1528
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    • 2008
  • 본 논문에서는 지하주차장 연결통로 및 엘리베이터 홀의 기계식 환기장치의 설치 및 적용을 위한 기초자료를 얻기 위하여 공동주택 지하주차장에 환기장치를 설치하여 실험을 수행하였다. 엘리베이터 홀의 경우 침기 및 누기(자연환기)로 인하여 실제 환기회수는 계산환기회수의 5배 정도 크게 나타났다. 지하 주차장 연결통로 및 엘리베이터홀의 환기장치는 동시 급 배기로 설치하는 것이 좋으며, 설치가 어려울 때에는 차선책으로 급기만이라도 설치하는 것이 공기질 측면에서 좋을 것이라 판단된다. 겨울철 환기장치 가동에 따른 콜드 드래프트의 영향을 고려하여 환기장치의 급기부에 예열기를 설치하는데, 환기시스템의 가동유무 및 가동방법을 다르게 하여도 지하주차장 연결통로 및 엘리베이터 홀의 온도가 $7{\sim}8^{\circ}C$로 일정하게 유지되어 나타나므로 한국의 남부지역에서는 단순 급 배기 환기장치에 예열기를 설치하지 않아도 될 것으로 판단된다.

스틸스터드의 압축내력 평가 (An Evaluation of Axial Compressive Strength in Steel Stud)

  • 신태송
    • 한국강구조학회 논문집
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    • 제10권4호통권37호
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    • pp.677-689
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    • 1998
  • 본 연구에서는 중심압축력을 받는 스털스터드의 설계강도에 대하여 다루었으며 비교 평가하였다. 미국규준인 냉간성형 LRFD 설계규준 (AISI). 유럽의 냉간박벽부재설계규준 (EC3 part 1.3) 및 독일의 관련규정 (DASt-Richtlinie 016)의 유사성과 차이점을 소개하고 분석하며 체계적으로 평가하였다. 특히 유효폭과 전체 안정성문제 (휨좌굴과 비틀림좌굴)가 이 논문에서 내포되어 있다. 또한 예제를 통하여 두 규준인 AISI와 EC3에 의한 설계압축강도를 산정하고 비교 분석하였다.

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소듐냉각고속로 잔열제거계통 강제대류 소듐-공기 열교환기의 구조개념 설계 (Structural design concept of the forced-draft sodium-to-air heat exchanger in the decay heat removal system of PGSFR)

  • 김낙현;이사용;김성균
    • 한국압력기기공학회 논문집
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    • 제12권1호
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    • pp.78-84
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    • 2016
  • The FHX (Forced-draft sodium-to-air Heat Exchanger) employed in the ADHRS (active decay heat removal system) is a shell-and-tube type counter-current flow heat exchanger with M-shape finned-tube arrangement. Liquid sodium flows inside the heat transfer tubes and atmospheric air flows over the finned tubes. The unit is placed in the upper region of the reactor building and has function of dumping the system heat load into the final heat sink, i.e., the atmosphere. Heat is transmitted from the primary cold sodium pool into the ADHRS sodium loop via DHX (decay heat exchanger), and a direct heat exchange occurs between the tube-side sodium and the shell-side air through the FHX tube wall. This paper describes the DHRS and the structural design of the FHX.