• Title/Summary/Keyword: Tightness

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An economic evaluation of heat exchanger for heat recovery ventilation (폐열회수환기를 위한 열교환장치의 경제성 평가)

  • Park, Yong-Hyo;Lee, Sang-Bum
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.11a
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    • pp.241-244
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    • 2008
  • Recently, The high Air-Tightness and high heat insulation for building construction cause a ventilation air volume deficiency. Also, Worldwide high energy price is strongly urging to economize the air conditioning energy. Therefore Heat Recovery Ventilation is used for the satisfaction of ventilation air volume and building energy saving. Accordingly, this study dose the heat exchanger performance evaluation and economic efficiency evaluation of Heat Recovery Ventilation. And, we wish to make a basic study about HRV System application of HVAC System and Multi System Air-conditioning.

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Mechanical Properties of Blast Furnace Slag Fineness Mortar according to Alkali Activator (알칼리 자극제 종류에 의한 고로슬래그 미분말 모르타르의 강도 특성)

  • Kim, Jong-Hee;Kim, Gyu-Yong;Shin, Kyoung-Su;Nam, Jeong-Soo;Koo, Kyung-Mo;Yun, Yong-Sang
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2011.11a
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    • pp.217-218
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    • 2011
  • The advantages of blast-furnace slag concrete may include lower hydration heating velocity, restraint on concrete temperature increase, long-age strength improvement due to latent hydraulic reaction, improved water tightness, and repulsion to chemical erosion. These advantages contribute to the high quality of the blast-furnace slag concrete. However, the blast-furnace slag concrete has its limitations as well. These disadvantages may include retarded setting and elongated retention of mold due to the weak strength of early-age. Nevertheless, much research is currently under way to improve the aforementioned issues. To improve activity of blast furnace slag powder, alkaline irritants has been used. In this study, we analyze effect on activity fineness and rate of substitution of Alkali Activator toward activity.

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Posture guidance system using 3-axis accelerometer for scoliosis patient (3축 가속도 센서를 활용한 척추 측만증 환자용 자세 교정 유도 장치)

  • An, Y.S.;Kim, K.S.;Song, C.G.
    • Proceedings of the IEEK Conference
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    • 2009.05a
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    • pp.396-398
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    • 2009
  • Scoliosis is a three-dimensional deformity caused by lateral curvature of the spine. The existing braces used to correct the posture were some drawbacks such as inconvenience, tightness as well as unfitness to wear. In this study, we devised a posture guidance system in order to monitor a posture continuously and lead to pose correctly and a new method fur measuring a Cobb's angle value in third dimension based on two 3-axis accelerometers. As a result, the correlation coefficients between desired and measured angles were and standard error between desired and measured angles were 0.99, 1.32(x-axis), 0.99 and 1.10(y-axis), respectively. The devised system showed good potential for the optimal posture guide and an early detection of scoliosis.

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A Numerical Analysis Study on the Characteristics for Packing Design of Cryogenic Gate Valve (초저온 게이트 밸브용 패킹의 수치해석 연구)

  • Kim, Si-Pom;Jeon, Rock-Won;Hwang, Il-Ju;Lee, Jae-Hun;Kang, Dae-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.3
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    • pp.160-165
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    • 2012
  • The packing, among the components comprising the gate valve, is used to sustain the air-tightness and the study on change of shape or pattern has been carried out to maximize the functions, but the study on changing the location or the size of the packing in a bid to prevent the freezing has rarely been implemented. Thus, This study is intended to evaluate the thermal strain of packing by heat transfer from territory of extremely low temperature as well as the temperature distribution to the upper part of the packing using numerical analysis method.

A Study of Muscular Imbalance (근육 불균형에 관한 연구)

  • Bae, Sung-Soo;Kim, Byung-Jo
    • The Journal of Korean Physical Therapy
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    • v.13 no.3
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    • pp.821-828
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    • 2001
  • Muscle imbalance describes the situation in which some muscles become inhibited and weak, which others become tight, losing their extensibility. Muscle imbalance develops mainly between tightness and inhibition. Although muscle imbalance involves the whole body, the imbalance is more evident or starts to develop gradually and predictably in the pelvic region, where we speak about the pelvic or distal crossed syndrome, and the shoulder girdle. neck region, associated with a proximal or shoulder girdle crossed syndrome. Evaluation of muscle imbalance in a patient can be from location of the line of gravity in relation to the trunk.

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A NOTE ON SPACES DETERMINED BY CLOSURE-LIKE OPERATORS

  • Hong, Woo Chorl;Kwon, Seonhee
    • East Asian mathematical journal
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    • v.32 no.3
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    • pp.365-375
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    • 2016
  • In this paper, we study some classes of spaces determined by closure-like operators $[{\cdot}]_s$, $[{\cdot}]_c$ and $[{\cdot}]_k$ etc. which are wider than the class of $Fr{\acute{e}}chet-Urysohn$ spaces or the class of sequential spaces and related spaces. We first introduce a WADS space which is a generalization of a sequential space. We show that X is a WADS and k-space iff X is sequential and every WADS space is C-closed and obtained that every WADS and countably compact space is sequential as a corollary. We also show that every WAP and countably compact space is countably sequential and obtain that every WACP and countably compact space is sequential as a corollary. And we show that every WAP and weakly k-space is countably sequential and obtain that X is a WACP and weakly k-space iff X is sequential as a corollary.

The Performance Field-Application of Natural Ventilation System (자연환기시스템의 현장 적용성 평가-열환경,에너지부분)

  • Choi, Dong-Hyuk;Choi, Gyoung-Seok;Kang, Jae-Sik;Lee, Seung-Eon
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.689-694
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    • 2009
  • On account of Indoor Air Quality(IAQ) deterioration by reason of high isulation and air tightness for energy saving, absence of energy efficiency ventilation system development that can be domestic existing window system, the cost increase and the energy addition loss by mechanical ventilation for IAQ improvement the ventilation obligation making design standard was prepared by a social and technical background and the necessity. In this study, open module type natural ventilation window system for energy saving included a fixed and continuous quantity ventilation was developed. The purpose that indoor thermal comfort environment evaluate of indoor resident.

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An Optimized Design and Simulation Analysis of Natural Ventilation Window System classified by Apartment type (주거용 건물 유형별 자연환기시스템의 최적 설계 및 해석)

  • Choi, Gyeong-Seok;Jeong, Young-Sun;Kang, Jae-Sik;Lee, Seung-Eon;Jeong, Yeong-Yong
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.685-688
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    • 2009
  • On account of Indoor Air Quality(IAQ) deterioration by reason of high insulation and air tightness for energy saving, absence of energy efficiency ventilation system development that can be domestic existing window system, the cost increase and the energy addition loss by mechanical ventilation for IAQ improvement, the ventilation obligation making design standard was prepared by a social and technical background and the necessity. In this study, an optimized design and simulation Analysis of natural ventilation window system classified by Apartment type was evaluated by CFD Computational analysis.

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Internal Impingement of the Shoulder (내적 충돌 증후군)

  • Kim, Yang-Su
    • The Academic Congress of Korean Shoulder and Elbow Society
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    • 2007.11a
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    • pp.153-161
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    • 2007
  • 견관절의 ABER position에서 posterosuperior rotator cuff 가 posterior glenoid에 contact 하여 internal impingement가 일어나는 현상은 운동선수가 아닌 일반인에게도 발생하는 physiologic phenomenon이며 과도한 반복 동작으로 인하여 증상이 발현한다. Internal impingement는 증상이 모호할 뿐만 아니라 견관절 내 여러 병소가 함께 존재하기 때문에 각각의 pathology에 대한 자세하고 정확한 evaluation이 필수적이다. 아직 controversy가 있지만 internal impingement의 pathologic factors로서는 anterior capsular laxity (true anterior laxity), posteroinferior capsular tightness (pseudo anterior laxity)와 이로 인한 glenohumeral internal rotation deficit (GIRD), 그리고 SICK scapula syndrome (scapular dyskinesis) 등으로 요약할 수 있다. 진단은 주로 병력 청취와 신체 검사로 내려지며 ultrasonogram, MRA등으로 확진한다. Sleeper stretching exercise 등과 같은 보존적 치료에 반응이 좋지만 6개월간의 재활 치료에도 호전이 없다면 증상과 직접 관련된 주 병소(appropriate pathology)를 찾아 이에 대한 적절한 수술이 이루어져야 한다.

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A Study on the Tube/tubesheet Interface in the Heat Exchangers Jointed by Explosive Bonding (폭발접합된 열교환기류 튜브와 튜브시트의 계면 특성에 관한 고찰)

  • 이병일;공창식;이상철
    • Journal of Welding and Joining
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    • v.18 no.4
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    • pp.38-47
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    • 2000
  • Characteristics of the interface between tube and tube sheet which were formed by explosive expansion and roll expansion, have been studied in the research. The results are as follows: Optimum amounts of explosives for the expansion of Alloy 600 (19.05mm and 15.88mm) were found to be RDX 3.5-8.5g/m. Because explosive expansion caused les strain hardening and increased bounding strength, characteristics of the explosively expanded were better than those of mechanically expanded. As the transition region of the explosive expansion is inactive, the resistance to the stress corrosion cracking increases by 30∼40% compared to the roll and hydraulic expansion.

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