• Title/Summary/Keyword: Cold draft

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

  • Ahn Jaehwan;Lee Youngho;Lee In-Woo
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.08a
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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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Comparison of Indoor Thermal Environments in Winter depending on Supply Vent Configurations (급기구 형상에 따른 겨울철 실내 온열환경의 비교)

  • Han, Hwa-Taik;Jeong, Young-Kyun
    • Proceedings of the SAREK Conference
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    • 2008.06a
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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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A Study of Hybrid Ventilation System applying to an Apartment House (공동주택용 하이브리드 환기설비에 관한 연구)

  • Yi, Seong-Hwan
    • Proceedings of the SAREK Conference
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    • 2006.06a
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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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Numerical method for Thermal Convection of air in Ondol Room (실내 기류의 수치해석)

  • Min Man-Ki;Kim Joo-Kyoon
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.7 no.1
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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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A Field Measuring Study on the Thermal Environment of Human Surrounding in the Classroom Equipped with Ceiling Unit (천장형 유닛을 설치한 교실 내의 인체 주변 온열환경에 관한 실측연구)

  • Cho Sung-Woo;Im Young-Bin;Lee Kyung-Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.3
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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.

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

  • Kim, Dockyu;Lee, Hyoungseok
    • Korean Journal of Microbiology
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    • v.55 no.1
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    • pp.83-85
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    • 2019
  • Pseudomonas sp. PAMC 29040 was isolated from a maritime tundra soil in Antarctica for its ability to degrade lignin and subsequently confirmed to be able to depolymerize heterogeneous humic substance (HS), a main component of soil organic matter. The draft genome sequences of PAMC 29040 were analyzed to discover the putative genes for depolymerization of polymeric HS (e.g., dye-decolorizing peroxidase) and catabolic degradation of HS-derived small aromatics (e.g., vanillate O-demethylase). The information on degradative genes will be used to finally propose the HS degradation pathway(s) of soil bacteria inhabiting cold environments.

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

  • 유은광
    • Journal of Korean Academy of Nursing
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    • v.25 no.4
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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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An Experimental Study on Ventilation of Connection Passage and Elevator Hall of Underground Parking in the Apartment Houses (공동주택의 지하주차장 연결통로 및 엘리베이터 홀의 환기에 관한 실험적 연구)

  • Kim, Il-Gyoum;Park, Woo-Cheul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1523-1528
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    • 2008
  • In this study, the ventilation system of connection passage and elevator hall of underground parking lot in apartment houses is investigated to extract the data for the installation and the application by the experimentation. In case of the elevator hall, actual air exchange rate is predicted fivefold higher than air exchange rate by infiltration and exfiltration. Ventilation system is installed good by supply air and return air. As the next best thing, it is installed by supply air because of IAQ control. The temperature of connection passage and elevator hall uniformly with $7{\sim}8^{\circ}C$, is maintained even if the operating condition of ventilation system is different. Therefore, the installation of the preheater, which is installed at the inlet of ventilation system for the cold draft in winter, is not essential in southern area of Korea.

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

  • Shin, TaeSong
    • Journal of Korean Society of Steel Construction
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    • v.10 no.4 s.37
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    • pp.677-689
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    • 1998
  • In relation to concentrically loaded compression, this research is to describe, analyze, and evaluate the design strength in steel stud. The similarity and difference among load and resistance factor design specification for cold-formed steel structural members (AISI), cold-formed thin gauge members and sheeting (EC3 part 1.3), and German draft (DASt-Richtlinie 016) are introduced, discussed, and systematically evaluated. Especially, the effective width and global instability problems (flexural buckling and torsional flexural buckling) are here implied in this research. The design axial strength by dual standards (AISI and EC3) is calculated and compared using the example.

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

  • Kim, Nak Hyun;Lee, Sa Yong;Kim, Sung Kyun
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.12 no.1
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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.