• 제목/요약/키워드: Stagnant

검색결과 478건 처리시간 0.028초

바닥 복사난방 배관설비에서 배관파열 사례 연구 (A Case Study on the Plumbing Pipe Burst of Floor Radiant Heating)

  • 정홍도;신용한;박진관;정효민;정한식
    • 설비공학논문집
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    • 제24권10호
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    • pp.745-749
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    • 2012
  • Heating pipes burst was occurred in the apartment complex that was applied floor radiant heating system. There were two opinions for the cause of the bursted heating pipes that was the flaw during construction and defects in the product and also there were conflicting among them. Officials analyzed it in order to investigate the cause of the rupture. Tensile test results showed different tensile strength between the lower part of heating pipe and the upper part of heating pipes. The lower tensile strength is maintained while the top was not secured. The reason why rupture heating pipes is that flow velocity isn't secured and then the air get stagnant. Stagnant air makes hardening. It is caused rupturing. The proper flow rate was confirmed 0.166 m/sec after experiment. It isn't make stagnant air inside heating pipes.

상향류 활성탄 생물막 공정을 이용한 정체 수역 수질 개선 및 공정 내 미생물 군집 해석 (Water Quality Improvement of Stagnant Water using an Upflow Activated Carbon Biofilm Process and Microbial Community Analysis)

  • 오유미;이재호;박정진;최기충;박태주;이태호
    • 대한환경공학회지
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    • 제32권1호
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    • pp.23-32
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    • 2010
  • 정체수역에서는 자연적 흐름의 차단으로 인해 자정능력이 떨어지며, 영양염류의 축적으로 인해 부영양화와 같은 문제점이 발생한다. 또한 비점오염물질의 유입은 정체수역 내 난분해성 물질을 증가시킨다. 본 연구에서는 정체수역의 수질개선을 위해 무산소조, 호기1조, 호기2조로 구성된 장치형 상향류 활성탄 생물막 반응기를 도입하여 정체수의 연속적 순환에 따른 오염물질 농도의 변화를 모니터링 하였다. 정체수역을 모사하기 위하여 $2m^3$의 저장탱크에 유원지의 호소수를 저장하였으며, 수질개선을 위한 최적 유입 유량을 산출하기 위하여 HRT가 6 hr, 4 hr, 2 hr 가 되도록 호소수의 유입 유량을 변화시켰다. 이 가운데 HRT 4 hr에서 SS, $BOD_5$, $COD_{Mn}$, $COD_{Cr}$, TN, TP의 제거 효율이 각각 69.8, 83.0, 91.3, 74.1, 74.7, 88.9%로 가장 좋은 수질 개선 효과를 얻을 수 있었다. 이에 HRT를 4 hr로 고정하고 골프장 연못수를 운전했을 때 SS, $BOD_5$, $COD_{Mn}$, $COD_{Cr}$ TN, TP의 제거 효율이 각각 78.5, 78.0, 80.2, 74.9, 55.6, 97.5% 달성되었다. 각 조건에서의 미생물 군집 변화를 PCR-DGGE를 사용하여 분석 결과, 유입수를 골프장 연못수로 교체함에 따라 미생물 군집에 변화가 나타났다. 또한 FISH에 의해 유입 유량 변화에 따른 질산화 미생물량의 변화를 관찰한 결과, HRT 4 hr의 조건에서 질산화 미생물이 가장 우점화됨을 알 수 있었다. 미생물량 및 INT-DHA를 이용한 미생물 활성도 실험 결과, HRT를 낮게 유지하였을 때에도 감소되지 않았다. 따라서 상향류 활성탄 생물막 공정을 정체 수역의 효과적인 수질 개선에 충분히 적용할 수 있을 것으로 기대한다.

인체를 대상으로 하는 혈허 혈어증 모델 개발을 위한 손톱 주름살의 모세혈관에 대한 영상장치 연구 ( I ) (Study on the Image Analysis System of Nail-fold Capillary Vessel( I ))

  • 김경철;황원덕
    • 동의생리병리학회지
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    • 제18권3호
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    • pp.789-791
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    • 2004
  • We study on the video-capillaroscopy system for look a.t the nail fold capillary by the computer. This system is composed of the luminous source-producer, image-input, phase microscope. The method and contents of observation on this system are seperated from the image-analysis of nail fold capillary form-patterns and the currents of hematocytes. Therefore we think this system is possible to the practical clinic use for the basic model on the cardiac failure and the deficiency(血虛), stagnant(血瘀) of blood in human.

Size Measurements of Droplets Entrained in a Stagnant Bubbling Liquid Column

  • Jeong, Hae-Yong;No, Hee-Cheon;Song, Chul-Hwa;Chung, Moon-Ki
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1996년도 추계학술발표회논문집(1)
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    • pp.254-259
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    • 1996
  • Phase Doppler particle analyze. (PDPA) is a instrument which can be used to obtain simultaneous size and velocity measurements in a multiphase flow. In this study, the size of the water droplets entrained from a bubbling surface of a stagnant liquid column is measured by PDPA with a specially designed transmitter of long focal length and large beam diameter. The test section tube is made of acryle with 18 mm I.D. and 900 mm length. The experimental data are obtained for the air superficial velocity between 0.7 m/s to 3.4 m/s at atmospheric pressure. The experimental results show that there exists large difference in the entrainment mechanism between the churn-turbulent flow and annular flow. Through the present study, the phase Doppler analyzer system is shown to be successfully applied to measure particle sizes larger than $2,000\mu\textrm{m}$ if a transmitter of long focal length is utilized.

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도시주부의 라이프 스타일 (Urban Housewives' Life Style)

  • 임정빈;임혜경
    • 가정과삶의질연구
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    • 제6권1호
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    • pp.223-249
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    • 1988
  • The aim of this study is to classify the life styles of urban housewives, to see their correlation with demographic and socioeconomic variables, and finally to provide some useful for their ideal home management. This study has been based on a questionnaire on the demographic characteristics of housewives, and their life styles. The selected samples were 650 and 514 of them were analyzed. The data wee analyzed by factor analysis, cluster analysis, ANOVA, Duncan test and X2-test. As a result of factor and cluster analyses of 64 items th life styles of urban housewives were classified into 5 types; 'conservative stagnant type', 'sound and thrifty type', 'passive stagnant type', realistic and stable type', modern and evolutional type', The life styles of the respondents showed significant differences by the variables of age , family life cycles, the number of family members, the number of children, family type, education, occupation, income, the type of housing, and religion.

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초기 근대건축에서의 근대성의 의미 및 전통의 역할 -베를라헤의 '진화하는 역사성'에 대한 소고- (The Meaning of Modernity and the Role of Tradition in the Modern Movements of Architecture - A Study of Berlage's 'Evolving Historicity'-)

  • 임석재
    • 건축역사연구
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    • 제2권2호
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    • pp.119-130
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    • 1993
  • Berlage's importance in the history of the Modern Movements of Architecture lies in his effort to combine several sets of contradictory dual aspects of architectural values. Tradition and modernity are one of the contradictory dual aspects. For Berlage, tradtion and modernity were not tow opposing, but reconciliatory concepts. In this sense, Berlage thought that modernity did not mean a total rejection, but a reinterpretion of tradition. Berlage's concern with his contemporaty architectural situstion was how to revive the stagnant repetion of past styles in Historicism and, at same time, how to prevent an extreme rejection of tradition by the Avant-Gardists. Berlage's architectural belief that neither stagnant imitation of past styles nor extreme revolution can be an ideal model for his era, lies in a traditional art theory of 'style evolution' and the interpertation of Nature's lessons for it. This study is to understand Berlage's concept of 'style evolution' and the meaning of tradition and modernity in the early Modern Movements of Architecture.

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강한 압력 교란에 구속된 고압 액적의 연소 응답 (Responses of Droplet Evaporation to High-Pressure Oscillations)

  • 김성엽;윤웅섭
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1286-1291
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    • 2004
  • In order for studying pressure-coupled dynamic responses of droplet vaporization, open-loop experiment of an isolated droplet vaporization exposed to pressure perturbations in stagnant gaseous environment is numerically conducted. Governing equations are solved for flow parameters at gas and liquid phases separately and thermodynamic parameters at the interfacial boundary are matched for problem closure. For high-pressure effects, vapor-liquid interfacial thermodynamics is rigorously treated. A series of parametric calculations in terms of mean pressure level and wave frequencies are carried out employing a n-pentane droplet in stagnant gaseous nitrogen. Results show that wave instability in view of pressure-coupled vaporization response seems more susceptible at higher pressures and higher wave frequencies. Mass evaporation rate responding to pressure waves is amplified with increase in pressure due to substantial reduction in latent heat of vaporization. Augmentation of perturbation frequency also enhances amplification due to the reduction of phase differences between pressure perturbation and surface temperature fluctuation.

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Open-Loop Responses of Droplet Vaporization to Linear Normal Acoustic Modes

  • Kim, S.Y.;W.S. Yoon
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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    • pp.155-164
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    • 2004
  • In order for studying pressure-coupled dynamic responses of droplet vaporization, open-loop experiment of an isolated droplet vaporization exposed to pressure perturbations in stagnant gaseous environment is numerically conducted, Governing equations are solved for flow parameters at gas and liquid phases separately and thermodynamic parameters at the interfacial boundary are matched for problem closure. For high-pressure effects, vapor-liquid interfacial thermodynamics is rigorously treated. A series of parametric calculations in terms of mean pressure level and wave frequencies are carried out employing a n-pentane droplet in stagnant gaseous nitrogen. Results show that wave instability in view of pressure-coupled vaporization response seems more susceptible at higher pressures and higher wave frequencies. Mass evaporation rate responding to pressure waves is amplified with increase in pressure due to substantial reduction in latent heat of vaporization. Augmentation of perturbation frequency also enhances amplification due to the reduction of phase differences between pressure perturbation and surface temperature fluctuation.

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20대-30대 남성들의 라이프스타일에 따른 화장품 구매행동 (A Study on the Cosmetics Purchasing Behavior According to the 20-30 Year Old Men's Life Style)

  • 이문영;김용숙
    • 복식
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    • 제56권1호
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    • pp.56-69
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    • 2006
  • The purposes of this study were to identify cosmetics purchasing behavior according the 20-30 year old men's lifestyle. The results were as follows; 1. The factors of men's lifestyle were sense of fashion, participation of social activities, use of web-based information, sense of androgyny, economical efficiency, provision of web-base information, sport activities, and pursuit of change, and they were segmented into a passive stagnant group, a economic web-base information utilizing group, a positive social activity participation group, and a sensitive appearance change pursuit group. 2. Passive stagnant group used less information sources patronized cosmetics specialty store, did not select their cosmetics by themselves, and spent less for their cosmetics. Economic web-base information utilizing group used information sources positively, patronized cosmetics discount store or internet shopping, and spent less for cosmetics. Positive social activity participation group patronized cosmetics specialty store or discount store, but did not select cosmetics by themselves. Sensitive appearance change pursuit group patronized department store or internet shopping for cosmetics, selected cosmetics by themselves, and spent more. 3. Passive stagnant group showed a tendency of older, less educated, and lower incomes, but economic web-base information utilizing group were among the age of 20's, lower educated, and the unmarried with average incomes. Positive social activity participation group showed a tendency of older, highly educated, and the married with jobs, but sensitive appearance change pursuit group were among the age of 20's and university students with more incomes and pocket money.