• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2001년도 학술발표회 발표논문집
• /
• pp.267-270
• /
• 2001

It is difficult to install a ventilation window on the roof of single span greenhouse of arch shape. Investigation on the roof ventilation structure for those greenhouses was conducted. The effect of roof ventilation was evaluated by comparative experiments between greenhouse installing roof vent and having controlled side vent only. And ventilation efficiency was analyzed by experiments on the opening and closing operation of the roof and side vent.

• 대한치과의사협회지
• /
• 제25권1호통권212호
• /
• pp.59-70
• /
• 1987

Orthodontists, in evaluating maxillary impactd canines, must take into consideration the etiology of the problem. First, the possible etiologic factors must be eliminated. Thus some cases can be treated with orthodontic treatment alone without surgical trauma following window opening etc. Now, two cases are reported, which were treated without surgical intervention. Sometimes, impacted canine can be included in a plan for tooth removal due to its severe impaction and displacement. In such case, first premolar can be substituted for canine. One case which was treated by substituting maxillary first premolar for maxillary impacted canine is reported.

• KIEAE Journal
• /
• 제17권1호
• /
• pp.69-75
• /
• 2017

Purpose: Heat transfer analysis of recently developed 'slim type double-skin system window' were presented. This window system is designed for curtain wall type façade that main energy loss factor of recent elegant buildings. And the double skin system is the dual window system integrated with inner shading component, enclosed gap space made by two windows when both windows were closed and shading component effectively reflect and terminate solar radiation from outdoor. Usually double-skin system requires much more space than normal window systems but this development has limited by 270mm, facilitated for curtain wall façade buildings. In this study, we estimated thermophysical phenomena of our double-skin curtain wall system window with solar load conditions at the summer season. Method: A fully 3-Dimentional analysis adopted for flow and convective and radiative heat transfer. The commercial CFD package were used to model the surface to surface radiation for opaque solid region of windows' frame, transparent glass, fluid region at inside of double-skin and indoor/outdoor environments. Result: Steep angle of solar incident occur at solar summer conditions. And this steep solar ray cause direct heat absorption from outside of frame surface rather than transmitted through the glass. Moreover, reflection effect of shading unit inside at the double-skin window system was nearly disappeared because of solar incident angle. With this circumstances, double-skin window system effectively cuts the heat transfer from outdoor to indoor due to separation of air space between outdoor and indoor with inner space of double-skin window system.

• 대한소아치과학회지
• /
• 제32권2호
• /
• pp.191-199
• /
• 2005

본 연구는 매복된 치아를 교정력을 이용하여 견인할 때 견인의 대상이 되는 치아를 개창술로 노출시켜 브라켓을 부착하는 과정에서 혈액 오염이 일어날 수 있는 상황을 실험실 환경에서 재현한 다음, 이와 같은 오염의 유무와 접착제의 종류가 브라켓의 전단강도에 미치는 영향을 평가하기 위해 시행하였다. 본 연구의 결과 글래스 아이오노머의 전단 강도는 레진에 비해 모든 조건에서 낮은 수치를 보였으나 혈액 오염이 없거나 광조사 직전 오염된 경우 임상적으로 교정적 정출술에 적절한 전단 강도를 나타내었다. 두 재료 모두 접착제 적용 전에 치면이 혈액에 오염되었을 경우 다른 조건에 비해 현저하게 낮은 전단 강도를 보였으나 광조사 직전에 혈액에 오염되었을 경우에는 오염되지 않은 대조군과 유의한 차이가 없었다. 이상의 연구 결과, 개창술을 통해 브라켓을 부착할 경우 접착제 적용 직전 혈액 오염을 주의한다면 산부식 과정 이 생략되어 술식이 비교적 간단하고 접착 파절 후 치면에 접착제가 남아 있지 않은 장점을 지닌 글래스 아이오노머 접착제의 사용을 추천할 수 있을 것으로 사료된다.

• 한국재난정보학회 논문집
• /
• 제17권1호
• /
• pp.1-9
• /
• 2021

연구목적: 본 연구는 계단식 공동주택의 화재 시 차압 및 방연풍속 특성을 분석하고, 화재안전기준에서 제시하고 있는 방연풍속 기준의 실효성을 검증하는 것을 목적으로 한다. 연구방법: 실제 모델의 계단식 공동주택의 제연설계 및 거실의 창문 개방조건에 따른 방연풍속의 성능을 CONTAM 프로그램을 이용하여 분석하였다. 연구결과: 공동주택 제연설비의 차압성능은 만족하더라도, 방연풍속 성능은 거실창문의 개방조건에 따라 방연풍속의 성능이 나오지 않음을 알 수 있었다. 결론: 계단식 공동주택의 경우 화재안전기준에서 요구하는 '방연풍속' 기준에 대해 예외를 두는 방안의 검토가 필요하다.

• 한국음향학회지
• /
• 제32권1호
• /
• pp.43-55
• /
• 2013

최근 창호의 창틀에 폐열회수장치를 삽입한 일체형 환기장치인 일명 "창호일체형 폐열회수 환기장치"를 개발됨으로써 창문을 열지 않고도 에너지 손실을 최소화하면서 실내외 공기를 교환할 수 있게 되었다. 그러나 이 장치의 작동시 기계소음과 공력소음이 발생하여 실제 주거시설에 적합하지 않은 면이 있다. 따라서 본 연구에서는 창호일체형 환기장치의 소음을 설치상태와 무향실에서 측정하고 소음의 발생 원인과 소음전달 취약부분을 분석하였다. 또한, 창호일체형 환기장치내의 차음재와 흡음재를 설치하여 소음을 제어하기 위한 대안을 제시하였다. 연구결과, 환기장치의 소음원은 블로워로 나타났으며 소음의 주된 누출 원인은 환기장치 구조체의 낮은 차음성능 때문이었음을 알 수 있었다. 또한 이를 제어하기 위하여 장치 내부에 고무시트 등의 차음재를 설치한 결과 폐열회수환기장치의 소음기준인 40 dBA 이하를 만족함을 알 수 있었다.

• 한국화재소방학회논문지
• /
• 제27권3호
• /
• pp.20-29
• /
• 2013

실규모 환기부족 구획화재에서 수직 개구부의 형상 및 위치변화에 따른 열 및 화학적 화재특성 변화를 수치적으로 검토하기 위하여, 이론적 최대 공기 유입량을 결정하는 환기인자($A\sqrt{h}$)와 heptane pool 화재의 질량 감소율이 모든 조건에 대하여 동일하게 설정되었다. 주요 결과로서, 출입문 형상의 변화는 구획 내부의 열 및 화학적특성 변화에 큰 영향을 미친다. 창문 위치의 변화는 화재지속시간 및 재순환 유동구조를 포함한 추가적인 화재특성의 복잡한 변화를 초래하였다. 이들 결과는 개구부 유동 및 연료/공기의 혼합현상을 포함한 다차원 유동 및 화재특성을 통해 상세히 분석되었다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.276-279
• /
• 2008

In order to measure sound transmission loss (STL) of a shipboard window of small size, a special partition is built into the test opening between two reverberation rooms and the specimen is placed in that partition. For high sound insulation, the filler wall often has multi-layered structure such as double-brick wall or buckhead structure with thick steel plate, absorptive material, and sandwich panels. This paper discusses the installation method of a multi-layered filler wall that consist of gypsum boards, lead plates, and glass wool. The experimental results of various wall structures are introduced. The comparison between the results show that the sound bridge effect plays a significant role in lowering the maximum STL of the filler wall. It is also found that the higher the sound insulation performance of the filler wall is, the more important the franking transmission through other side wall of the test facility is.

• 한국입자에어로졸학회지
• /
• 제15권4호
• /
• pp.149-157
• /
• 2019

Infiltration characteristics of airborne particulate matter had been investigated in real-life for about 90 days over 2 years in a Korean apartment building where a 3-person household had lived and the exclusive private area was 84.9 ㎡. Airtightness was measured by fan depressurization, and the ACH₅₀ was 2.41 times per hour. In and outdoor particle concentrations were measured by optical particle counters. Infiltration factors and filtration efficiencies of the house, which reflect the removal of outdoor particles penetrating building envelope and the deposition inside a building, were obtained from data screened based on an empirical evaluation process. Infiltration factor of fine particles showed a range from about 42% at 0.4 m/s of wind speed to 72% at 4.2 m/s of wind speed with closed windows and doors. Filtration efficiency was like a MERV 13 grade filter with an open window outside at a balcony at low outdoor wind speed under 1 m/s. The grade decreased to MERV 11 by opening another outside window at the other balcony. Filtration efficiencies decreased as much as 29% in average at a range of 0.3~2.5 ㎛.

• 한국대기환경학회지
• /
• 제16권4호
• /
• pp.381-388
• /
• 2000

Ceramic foam prepared with cordierite as a starting material by foam method was tested to evaluate the feasibility as a filter for the dust collection in hot gas. Two different types of agents Benzethonium chloride (BZTC, C27H42NO2Cl) and Sodium Lauryl Sulfate(SLS, CH3(CH2)11OSO3Na) were used as foaming agents in foaming process. Porosityof ceramic foam was about 80% and mean pore size were 100${\mu}{\textrm}{m}$ for SLS agent and 200 ${\mu}{\textrm}{m}$ for BZTC. It was observed that ceramic foam was composed of continuous macro-pore structure with opening windows interconnecting macro-pores. The surface of ceramic foam support of was coated with cordierite particles ranged from 20${\mu}{\textrm}{m}$ to 50${\mu}{\textrm}{m}$ Meso-pore size in the coating layer on ceramic foam was below 10${\mu}{\textrm}{m}$. While air permeability of the support increased with increasing macro-pore size coated ceramic filters showed a constant permeability without regard to the macro-pore size of the support. The permeabuilities of support varied in the range of 600$\times$10-13m2 to 1000$\times$10-13m2. For the case of coated ceramic filter it was about 200$\times$10-13m2. As a result of particle trapping test by using fly ash the particle removal efficiency was over the 99.9%.