• 콘크리트학회지
• /
• 제7권4호
• /
• pp.109-118
• /
• 1995

콘크리트의 침투성은 내구성과 밀접한 관계가 있고, 콘크리트의 내구성은 침투성 특성에 의해서 간접적으로 측정될 수 잇다. 실험 결과에 의하면 콘크리트의 침투성에서 플라이애쉬의 양이 증가할수록 (15%, 30%, 그리고45%) 침투성이 낮아졌으며, 기건양생한 콘크리트가 수중양생한 것에 비해서 월등히 높은 침투성을 보여 주었으나. 그 차이점은 플라이애쉬를 섞는 양이 많을수록 줄어 들었다. 높은 비율의 플라이애쉬(45%) 다양한 조강 시멘트를 섞어 만든 콘크리트에서도, 플라이애쉬 콘크리트가 보통(PCI)콘크리트보다 낮은 침투성을 보여주었다. 콘크리트는 양생기간이 길어짐에 따라 시멘트종류에 관계없이 침투성이 낮아졌으나, 기건양생시에는 증가하는 것을 보여주었다. 침투성 특징에서 모든 콘크리트는 물을 이용해 시험한 것이 기체를 이용해 시험한 것 보다 항상 낮은 값을 갖는다는 것이 발견되었다. 콘크리트의 침투성은 그것의 강도가 증가함으로써 줄어드는 것을 발견하였으나, 침투성의 특징은 주로 사용한 시멘트종류와 좀더 밀접한 관계가 있는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
• /
• pp.62-65
• /
• 2003

In this study, to confirm corrosion of reinforced concrete affected by carbonation, chloride ion diffusion, absorption ratio, air permeability, measured carbonation velocity coefficient, chloride ion diffusion coefficient, absorption coefficient, air permeability coefficient. Corrosion velocity under environment of complex deterioration. And than compared corrosion velocity with these coefficients. As the results of this study, the correlation coefficient between chloride ion diffusion coefficients and absorption coefficient was revealed that it is very high. As well, an increase in carbonation, chloride ion diffusion also increases corrosion velocity. It showed that corrosion velocity was affected by the carbonation, chloride ion diffusion, absorption ratio, air permeability. Generally, data on the development of these coefficient made with none, organic B, organic A, inorganic B, and inorganic A is shown. It showed that coating of surface prevent steel bar from deteriorating.

• 한국소음진동공학회논문집
• /
• 제17권4호
• /
• pp.342-349
• /
• 2007

Following the 2002 World-Cup held in Korea, studies have been actively conducted on plans to utilize all-weather stadiums of fine figures, where large-scale spaces are available for various utilizations. In Japan, dome-type stadiums have been built and are utilizing across the whole nation not only for sports events but also variety of other large-scale events. PTFE(poly tetra fluoro ethylene) is one of the membrane material mainly used for the outer ceiling surface of membrane structures. However, there has not been enough research on the acoustical properties of PTFE membrane material which has been widely used in the multi-purpose stadiums. In this study, air permeability values and sound absorption coefficient of PTFE membrane materials were measured and evaluated in the gymnasium. From the results of measurements of sound absorption coefficient and air permeability of inner membrane materials, it was found that the sound absorption coefficient was good in the air permeability range of $5{\sim}15\;cc/cm^2/s$. Also the relation ship between air permeability and sound absorption coefficient was very high and the sound absorption coefficient was the highest in the range of $6{\sim}9\;cc/cm^2/s$. Secondly, an analysis on the measurements sound absorption characteristics of inner membrane material reveals that the overall sound absorption coefficient was stabilized(higher than 0.5 throughout the whole frequency bands) when the air space behind the membrane material was deeper than 600 mm. When PTFE sound absorptive membrane material was installed in the ceiling of gymnasium, it was confirmed that sound absorptive membrane material can reduce reverberation and increase speech intelligibility in the gymnasium.

• 대한환경공학회지
• /
• 제22권7호
• /
• pp.1233-1241
• /
• 2000

디젤로 오염된 토양에서 토양증기추출(soil vapor extraction)과 생물학적통풍(bioventing)을 혼합한 파일럿 테스트를 실시하여 기술의 적용 가능성과 운전조건을 파악하였다. 본 연구에서는 오염된 지역의 복원율을 평가하는 중요한 인자인 공기투과도(air permeability)와 가스상 물질의 농도변화를 구하였다. 실험결과 공기투과도는 1985~1194 darcy로서 토양증기추출의 적용에 적합한 것으로 나타났다. 생물학적통퐁 실험에서는 실험결과 $3.5m^3/hr$의 유량으로 공기를 주입했을 때 미생물 활성도에 따른 생분해율이 가장 높았으며, 연구결과 이 지역과 같이 디젤로 오염된 지역에서 혼합형 시스템을 적용하는 것이 바람직할 것으로 판단된다.

• 설비공학논문집
• /
• 제28권9호
• /
• pp.367-372
• /
• 2016

Gas diffusion layer (GDL) of PEMFCs plays a role that it diffuses the reactant gases to the catalyst layer on the membrane and discharge water from the catalyst layer to the channel. Physical parameters related to the mass transport of GDL are mostly from the uncompressed GDLs while actual GDLs in the assembled stacks are compressed. In this study, the relation of compression and strain of GDLs with various Polytetrafluoroethylene (PTFE) loading is measured experimentally and In-plane gas permeability is measured at the condition that the GDLs are in compressive strain. The gas permeability decreased with the loading of PTFE and the presentation of gas permeability under compressive stain is expected to improve the accuracy of modeling work of mass transport in the GDL.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
• /
• pp.700-703
• /
• 2000

With respect to durability, the impotance of carbonation lies in the fact that it reduces the pH on the pore water in hardened concrete. However, the carbonation velocity is effected by the water/cement ratio, materials, unit cement weight, porosity, kinds of finishing materials, accuracy of constructing, environmental factors and so on. And the air permeability is closely related to the carbonation velocity because it represents the properties of concrete. This paper presents an experimental investigation on the carbonation effected by air permeability n mortar and concrete. As a result, it was found that the carbonation velocity of concrete is faster than that of mortar and it is possible to predict the carbonation velocity using air permeability.

• 한국의류산업학회지
• /
• 제3권1호
• /
• pp.15-19
• /
• 2001

The purpose of this study was to determine the thermal characteristics of men's suits ensembles and their fabrics. For the study, 100% wool fabrics were woven with various fabric structure, fabric density and yam count and With the use of these, 12 men's suits were made with the same design. Physical characteristics that affect thermal transport properties, including drapery, cover factor; bulk density, keeping warmth ratio, vapor permeability, air permeability and porosity of the fabrics were measured. In addition, thermal resistance of men's suit ensembles, including Y-shirts, inner wear and socks was measured on the thermal manikin in the environmental chamber. The result of the study was as follows: 1. In terms of fabric structure, keeping warmth ratio of plain woven fabrics was higher than those of twill and satin woven fabrics and also, vapor and air permeability and porosity of plain woven fabrics were higher than those of twill and satin woven fabrics. 2. The result showed that thermal resistance of 12 ensembles were in the range of 0.77clo~0.97clo. 3. There was little correlation between woven condition such as, including structure, fabric density and yam count and thermal resistance of ensembles.

• 대한화학회지
• /
• 제54권1호
• /
• pp.137-141
• /
• 2010

일반적으로 고분자 재질은 표면이 수분을 배척하는 소수성이며 또한 통기성이 좋지 못하다. 이러한 물성을 개질하기 위하여 고분자 플라스틱에 기능성 충전제로 친수성인 세라믹 입자와 항균입자를 혼합하여 친수성, 통기성 및 항균성이 향상 된 복합재료를 제조하였으며 표면 접촉각 측정, 공기투과시간 측정, 항균효과 관찰을 통해 물성을 확인하였다. 이러한 복합 재료는 건강관련 제품에 널리 이용될 수 있다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 하계학술발표대회 논문집
• /
• pp.414-418
• /
• 2008

The effects of paper properties such as density, air permeability, water vapor transmission rate on the thermal performance of plate-type enthalpy exchanger were experimentally investigated. Three enthalpy exchanger samples having different properties were made, and were tested according to the standard test procedure (KS B 6879). Effective efficiencies were defined, which accounted for the air leakage between supply and exhaust streams. Results showed that paper density affected the sensible heat transfer of the samples. Sensible heat transfer increased with density of the paper. It was also shown that water vapor transmission rate alone was not a proper indicator for the efficiency of latent heat transfer. Air permeability should also be considered for adequate evaluation of the latent heat transfer. Best performance was obtained for the sample having highest paper density and moderate water vapor transmission ratio.

• 터널과지하공간
• /
• 제20권6호
• /
• pp.434-445
• /
• 2010

대용량 전력에너지저장시설로서의 복공식 압축공기 지하저장시설의 기밀시스템을 구성하는 콘크리트 라이닝 및 현장 타설 과정에서 발생하는 시공이음부의 투기특성을 파악하고자 콘크리트 블록시료를 이용한 모형실험을 수행하였다. 시공이음부의 투과계수는 콘크리트 블록보다 약 $10^1{\sim}10^4$ 배 정도의 투과성이 큰 것으로 파악되어, 현장 타설과정에서 시공이음부의 품질관리가 저장시설의 기밀성능 확보 관점에서 매우 중요함을 확인하였다. 또한, 접합면에 아크릴계 접착제를 타설함으로써 시공이음부의 투과계수를 콘크리트 블록 수준까지 감소시킬 수 있었으며 콘크리트 블록의 초기 수분함량이 높을수록 투과계수가 감소하여 기밀성능을 향상시킬 수 있음을 확인하였다.