• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 봄 학술논문 발표대회
• /
• pp.113-114
• /
• 2023

This study measured the thickness and speculation coefficient of the coating for existing buildings and calculated the diffusion coefficient of the coating to predict the depth of carbonation through numerical analysis in order to evaluate the impact of the external finish and local environment. As a result, it was possible to predict the short-term and long-term carbonation depth of reinforced concrete buildings coated with coating film with considerable reliability.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.645-648
• /
• 2005

The grounds of multipurpose practical use degree are built much holding world cup 2002 but material that is used in this building most external membrane ceiling is accomplishing PTEE A master and servant. Therefore, this research analyzed assessment about sound absorption special quality that measure ventilation quantitys of 10 act material and analyze correlation with Air Permeability and the sound absorption rate, and follow in change of layer of air of inside facts material. Result is as following. When Air Permeability good dimension is 5$\sim$15 cc/cm$^2$/sec and acoustic absorptivity is the best as Air Permeability result that measure acoustic absorptivity of inside facts material particularly firstly, could know 8$\sim$9 cc/cm$^2$/sec love. When establish sound absorption inside facts in external membrane as result that measure acoustic absorptivity of inside (acts material secondly, could know that acoustic absorptivity is good though become about minimum back layer of air 900mm.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
• /
• pp.379-380
• /
• 2010

본 연구는 국내 원전구조물에 사용된 실제 재료와 배합조건으로 시편을 제작하여 공학적 방벽의 재령에 따른 물리적 특성의 변화를 관찰하였다. 압축강도, 탄성계수, 투기계수, 투수계수를 측정하여 원전 콘크리트의 물리적 특성을 성능을 평가한다.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 추계학술발표회
• /
• pp.140-143
• /
• 2003

Air permeabilities in unsaturated fractured tuff at the Apache Leap Research Site (ALRS) near Superior, Arizona, exhibit a self-affine behavior, thus renders a field random fractal. Based up fractal scaling, the observed scale effect has been interpreted [Hyun et al., 2002]. Recently, Frantziskonis and Hansen [2000] presented that fractal scaling can be represented based on wavelets. This study deals with the way of using wavelets for fractal scaling. A numerical study is presented to examine the applicability of wavelet-based approach to determining upscaled air permeability values on various data supports at the site. To characterize the scaling property of self-affine fields generated based upon wavelets, Hurst coefficient, H. was inferred by applying the average wavelet coefficient (AWC) method. The result yielded H = 0.24, which is very close to the result of geostatistical analysis using a power variogram (H = 0.22). The study concludes that wavelet-based scaling is a useful way of determining parameter values on different data supports, which is an essential task for modeling of subsurface flow and mass transport in a numeric grid with different resolutions (grid size).

• 한국산업융합학회 논문집
• /
• 제26권6_2호
• /
• pp.1135-1144
• /
• 2023

In this paper, bending strength and permeability tests were conducted on concrete permeable blocks manufactured by recycling industrial by-products of oyster shell and blast furnace slag to measure and compare bending strength and permeability coefficient, and present experimental research results. To this end, a total of 54 specimens with a size of 200x200x60mm for surface layer and base layer were manufactured, and bending strength and permeability test were carried ourt accoridng to KS F 4419. Eighteen types of mixing designs were implemented by varying the mixing and replacement rates of oyster shells and blast furnace slag. As a result of the experiment, the higher the mixing ratio of oyster shell, the lower the bending strength and the permeability coefficient. Thereafter, a total of three permeable blocks with dimensions of 200x200x60mm were manufactured and subjected to bending strength and permeability tests according to KS F 4419. As a result of the test, the bending strength satisfies the standard of KS F 4419, and the permeability coefficient is 12 times higher than the standard of KS F 4419. It seems that the proper mixing of oyster shells and blast furnace slag increases the amount of air, and further research on durability and economic feasibility of materials used to manufacture permeable blocks is required.

• 콘크리트학회논문집
• /
• 제22권2호
• /
• pp.209-217
• /
• 2010

최근 콘크리트의 탄산화 진행 예측을 위한 수식적 모델들이 보고되고 있으며, 이러한 모델들은 $Ca(OH)_2$과 $CO_2$의 화학적 반응과 $CO_2$의 확산에 대한 관계를 연구하고 있다. 이 모델들은 콘크리트의 탄산화 영역에서 $CO_2$가 확산하고 콘크리트 중의 탄산화 영역과 미탄산화 영역과의 경계면에서 $Ca(OH)_2$와 반응한다는 가정에 기초하고 있다. 이 연구에서는 콘크리트중의 $CO_2$ 확산 및 탄산화진행영역에서의 $CaCO_3$와 $Ca(OH)_2$의 공존을 고려한 $CO_2$와 $Ca(OH)_2$와의 반응을 모델화한 것이다. 콘크리트 탄산화진행을 보다 정확하게 표현하기 위해 콘크리트 투기계수로서 탄산화진행모델에 적용하여 $CO_2$확산 계수를 유추하였다. 모델에 의한 예측은 W/C에 따라 페인트처리를 실시한 콘크리트의 촉진탄산화의 실험 결과와 아주 유사하게 나타나, 콘크리트 투기계수를 이용한 탄산화 진행속도 기본방정식을 활용하여 촉진환경 및 일반 대기환경에서 탄산화 진행예측이 가능함으로서 철근콘크리트구조물의 내구성설계를 위한 보다 정량적인 수명예측이 가능할 것으로 사료된다.

• 펄프종이기술
• /
• 제33권1호
• /
• pp.64-72
• /
• 2001

The cigarette ventilation affects not only the amount of tar and nicotine delivery by a cigarette, but also the composition of the smoke. Therefore, it is important to stabilize of variability in cigarette ventilation that would be affected by changes in cigarette components. This work was conducted to determine the major factors that influence the cigarette ventilation and also to provide fundamental informations for improving the uniformity of cigarette performances. To evaluate the effect of cigarette ventilation as a dependant variable, the three independent factors were the air permeability of plugwrap, tipping paper and the filter pressure drop. We determined the effect of paper permeability on ventilation variability and the optimum condition in combinations of independent factors. The mean of cigarette ventilation was increased as plugwrap permeability increases, particularly at 26,000 CU. However, it was exhibited that standard deviation and coefficient of variation of the cigarette ventilation were decreased with increasing plugwrap permeability. At the 600 CU and 1,200 CU of tipping paper permeability, process capability index (Cp) of the cigarette ventilation increased as plugwrap permeability increases. Following the optimum condition of cigarette ventilation induced by fitted regression equation, one was to optimize 50% ventilation level is by combination with plugwrap permeability of 16,000 CU, tipping paper permeability of 810 CU, filter pressure drop of 319 mm$H_2O$, respectively.

• 한국의류학회지
• /
• 제28권1호
• /
• pp.112-118
• /
• 2004

Recently, as the percentage of women employment has been growing, the demand for various facilities and services regarding household duties and infant rearing is increasing and so do the amount of the disposable diaper used. Among the components of disposable diaper, the top sheet contacting with infant skin directly is usually made with nonwoven textiles. Therefore, the mechanical and surface characteristics of the nonwovens used in disposable diaper are important for the skin health of infants. In this study, we have explored the mechanical and surface properties, such as friction coefficient, fluid permeability and strength, of the nonwovens used for disposable diaper top sheet and observed the variation of their properties with abrasion cycles. Nonwoven materials examined in this study are 100% cotton spunlace, 100% tencel spunlace, 100% polypropylene (PP) thermal bonding and 100% PP air through (Thru-air bonded carded web). From the result of KES-F analysis, we've found that 100% PP air through type nonwoven had a low friction coefficient and showed a little change in surface properties as increasing abrasion cycles. Moreover, it revealed superior fluid permeability and quick-drying character. On the other hand, though showing an excellent absorption force, the spun lace type nonwoven made of 100% cotton and 100% tencel displayed relatively low abrasion strength especially in wetting condition.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 하계학술발표대회 논문집
• /
• pp.754-757
• /
• 2008

To maintain the indoor air quality, many ventilation systems and technologies have been developed in the highly insulated and air tight buildings. In this study, a porous construction material, which is applicable to passive ventilation system, is developed and measured the performances of the permeability and the resistance of water vapor, and the dust collection efficiency. The average coefficient of water vapor permeability shows $3.6\;g/m^2{\cdot}h{\cdot}mmHg$, which is slightly higher than Hanji ($2.4{\sim}3.2\;g/m^2{\cdot}h{\cdot}mmHg$) and the average water vapor resistance factor shows $0.303\;g/m^2{\cdot}h{\cdot}mmHg/g$, which is slightly smaller than Hanji($0.309{\sim}0.315\;g/m^2{\cdot}h{\cdot}mmHg/g$). The pressure drop of the porous construction material is smaller than the HEPA filter and the minimum dust collection efficiency shows 82.8% in the range of $2{\sim}9\;cm/s$.

• 설비공학논문집
• /
• 제11권2호
• /
• pp.185-192
• /
• 1999

Effective thermal conductivities and pressure-drop-related properties of aluminum foam metals have been measured. The effects of porosity and cell size in the aluminum foam metal are investigated in detail. The porosity of the foam metal, considered in the present study, varies from 0.89 to 0.96 and the cell size from 0.65㎜ to 2.5㎜. The effective thermal conductivity is evaluated by comparing the temperature gradient of the foam metal with that of the thermal conductivity-known material. The pressure drop in the foam metal is measured by a highly precise electric manometer while air is flowing through the aluminum foam metal in the channel. The results obtained indicate that the effective thermal conductivities are found to be increased with a decrease in the porosity while the effective thermal conductivities ire little affected by the cell size at a fixed porosity. However, the pressure drop is strongly affected by the cell size as well as the porosity. It is seen that the pressure drop is increased as the cell size becomes smaller, as expected. The minimum pressure drop is obtained in the porosity 0.94 at a fixed cell size. A new correlation of the pressure drop is proposed based on the permeability and Ergun's coefficient for the aluminum foam metal.