• 한국가구학회지
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• 제19권6호
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• pp.447-451
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• 2008

This study was carried out to know the difference of vapor transmission on the thickness of Paulownia wood(Paulownia tomentosa). The behavior of moisture transmission of wood thickness direction is generally estimated by vapor permeability and vapor transmission resistance. In general, Paulownia wood is known to use of inside material for furniture making, because of the excellent ability of vapor adsorption and/or desorption. Quarter sawing Paulownia wood material is prepared and the thickness is 6.0mm, 7.0mm, 8.0mm, 9.0mm, 10.0mm, respectively. The measurement of vapor transmission were conducted by the "cup method" in accordance with JIS(Japanese Industrial Standard) Z-0208. The experiment was made in the condition of 49.8mmHg vapor pressure difference and $40^{circ}C$ at constant temperature. From the experiment results, it was considered that Paulownia wood is very stable on moisture variation and any other material conditions. In this experiment we found that the vapor permeability and vapor permeance was reduced with the increase of wood thickness to vapor direction and vapor transmission resistance and specific vapor transmission resistance was increased with the increase of wood thickness to vapor direction. Besides moisture contents of adsorption and desorption side were about 5 percent and 14 percent, respectively. Mean value was 9.5 percent and about 10 percent in dry oven method. Moisture gradient was reduced with the increase of wood thickness for a small moisture difference of adsorption and desorption side.

• Journal of the Korean Wood Science and Technology
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• 제20권3호
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• pp.21-27
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• 1992

The amount of moisture transmitted under four different humidity conditions was measured in earlywood and latewood for Cryptomeria japonica(LT specimens). The results obtained are summarized as follows. The vapor permeability in eariywood was about three times larger than that of latewood. The vapor permeabilities in earlywood and late wood depended on the average moisture content of the wood. This indicates that moisture transmission is influenced by vapor permeability or vapor-transmission resistance, but the values obtained by experiments do not have great adaptability for practical situations because of changes in the experimental conditions. There fore, it is necessary to know the moisture content along the flow direction in order to explain the moisture transmission of wood. The vapor permeability was calculated using the density in air dried wood. These were then compared with the experimental values. The vapor permeabilities calculated with this density in the radial direction(LR specimen) had a good tendency to agree with the experimental values, but not so in tangential direction(LT specimen).

• 한국의류학회지
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• 제16권2호
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• pp.237-244
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• 1992

The purpose of this study was to comparatively evaluate thermal and water transmission properties of several vapor permeable water repellent (VPWR) fabrics and synthetic battings that became available in recent years. Five VPWR fabrics evaluated were Hipora in three coating variants, $Gore-Tex^{\circledR}$ and $Aitace^{\circledR}$. Battings evaluated were $Viwarma^{\circledR}$, $Uniwarmr^{\circledR}$, $Thinsulate^{\circledR}$, and $Airseal^{\circledR}$ Thermal resistance and water vapor transmission were measured for each fabric and batting and in all combinations. Thermal resistance at zero and 37 cm/sec air velocity was determined by the Thermo Labo II technique for simultaneously measuring conduction and radiation heat transfer. Water vapor transmission over 24 hours was measured by a modified weight-gain method in a compact humid chamber at conditions simulating the clothing climate under heavy exercise ($40{\pm}1^{\circ}C$, $90{\pm}2\%$ R.H., and 0.5 m/sec air velocity). Fabric porosity was calculated from fiber density and fabric weight, thickness, and area. Thermal resistance results for the fabrics showed the effectiveness of coatings in inhibiting heat transfer. Measurements taken in wind were: $31.1\~37.6\%$ for $Hipora^{\circledR}$ variants; $31.0\%$ for $Gore-Tex^{\circledR}$; and $18.4\%$ for $Aitaca^{\circledR}$ Measurements without wind were higher but in the same order. Water vapor transmission results were in reverse order: $Aitac^{\circledR}$, $8.8 kg/m^{2};\;Gore-Tex^{\circledR}$, 6.4 kg/$m^{2}$; and $Hipora^{\circledR},\;4.4\~6.0\;kg/m^{2}$. In general thermal resistance increased with porosity. For battings, the thermal resistance with wind results were: $Viwarmu^{\circledR}$, $65.0\%;\; Thinsulate^{\circledR}$, $62.0\%$; $Uniwarm^{\circledR}$, $61.0\%$; and $Airseala^{\circledR},\;53.1\%$. Thermal resistance was proportional to thickness. Thermal resistance of fabric-batting combinations were $20\%$ higher than those of the battings only. Water vapor transmission for combinations was mainly affected by that for the VPWR fabric used.

• 한국포장학회지
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• 제5권1호
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• pp.37-46
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• 1999

Water vapor permeability of films is commonly calculated from the water vapor transmission rate of the film measured using a permeability cup method which is essentially a gravimetric method. This method was originally developed for petroleum based plastic films with low water vapor permeability. In the case of hydrophilic bio-polymer films, the resistance caused by a stagnant air layer, which is developed between the underside of the film mounted on the cup and the surface of the desiccant saturated salt solution or distilled water, can be significant and, if neglected, ran lead to underestimation of water vapor transmission rates. Therefore, it is necessary to correct water vapor transmission rate data to accurately estimate the water vapor permeability of bio-polymer films.

• 한국전기전자재료학회논문지
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• 제15권8호
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• pp.687-694
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• 2002

In order to replace the jacket material for URD power cables, the 6 kinds of polyethylene compounds were manufactured and evaluated. The characteristics of the compounds were investigated by water vapor transmission (WVT) test, thermal and mechanical test. In WVT test, all the polyethylene compounds showed the superior water resistance to conventional PVC. The molecular structure and density of polyethylene play an important role in WVT. Also, the polyethylene compounds showed the suitable characteristics in thermal and mechanical test. Especially, the linear polyethylene compounds showed the superior characteristics to LDPE ones. Due to the fillers in compounds, the abrasion resistance was decreased and the cut-through resistance was increased. From this study, it can be considered that the polyethylene compounds may be suitable to jacket material for URD power cables.

• Current Research on Agriculture and Life Sciences
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• 제10권
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• pp.41-47
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• 1992

목재투습성에 관하여 다음과 같은 결과가 밝혀졌다. 1) 시편두께 0mm에 외삽한 투습저항값이 정(正)이므로 목재표면에서의 수분전달현상을 고려함이 인정되었다. 2) 목재내부의 함수율분포는 함수율 9%를 경계로 두 개의 직선으로 나타났다. 또 시편양측의 공기중 평형함수율이 9%이상일 때는 한 개의 직선으로 나타났다. 수분확산계수는 함수율 9%를 경계로 두 개의 일정한 값을 가지며, 이 값들은 오직 함수율에만 관계한다. 4) 수분이동량은 목재내의 함수율구배에 의존한다. 4) 목재의 수분전달계수는 시편두께에 의존하였다. 이 현상의 기구에 대해서는 아직 알 수 없다.

• 공업화학
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• 제29권4호
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• pp.484-487
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• 2018

본 논문에서는 유기전자소자에서 사용되는 수분 차단막의 투습도 분석을 위하여 ytterbium의 광학적 전기적 특성을 연구하였다. Ytterbium 박막은 다양한 성막 두께(20-100 nm)에 따라 넓은 범위의 광투과도(70-10%)와 비저항($6.0-0.16m{\Omega}{\cdot}cm$) 값을 나타내었다. 25 nm의 ytterbium 박막은 수분과 반응하여 산화되며 투과도와 저항이 실시간으로 변화하였고 이를 통해 parylene 고분자와 aluminum nitride 적층형 박막 봉지 필름을 분석한 결과 $4.3{\times}10^{-3}g/m^2{\cdot}day$의 투습도를 측정할 수 있었다.

• 한국의류학회지
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• 제17권4호
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• pp.577-586
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• 1993

Pesticide protective clothing has not been frequently worn due to its lack of thermal comfort. It is important to develop fabrics which can allow the wearer to work in comfort. One of the possible way to achieve the goal is to produce fabrics with a water- and oil-repellent finish which would resist pesticide penetration but maintain some breathability. The purpose of this study were to evaluate the pesticide barrier properties of untreated and water- and oil-repellent finished nonwoven fabrics. Three types of nonwoven fabrics(Tyvek, Sontara and Kimlon) were used as test specimens. By pad-dry-cure method, each of the specimen was treated with fluorocarbon. The pesticide barrier properties (amount of pesticide penetration and residue) were measured by the gas chromatography. The performance properties of untreated and treated specimens were evaluated with respects to water pepellency(KS K 0590), oil repellency(AATCC 118), water resistance(KS K 0591, AATCC 42), water vapor transmission (KS A 1013) and air permeability(KS K 0570). The results of this study were as follows : 1) The untreated Sontara showed much more amount of pesticide penetration than untreated Tyvek and Kimlon, while the treated Sontara showed little amount of pesticide penetration. 2) After laundering, the amount of pesticide residue in the untreated and treated Sontara was less than that in Tyvek and in Kimlon. 3) Water- and oil-repellent finish improved water repellency, oil repellency, and water resistance of specimens. 4) The untreated Sontara and Kimlon showed higher water vapor transmission and air permeability than untreated Tyvek. Water vapor transmission and air permeability of treated specimen decreased compared to those of untreated.

• 한국의류학회지
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• 제41권1호
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• pp.84-97
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• 2017

Water vapor and thermal transmission properties of high emotional garments are important to evaluate wear comfort; in addition, the measuring methods of these properties are also critical for breathable and warm suit fabrics. In this study, the water vapor and thermal properties of composite yarn fabrics made of CoolMax, Tencel, and Bamboo fibers with filaments were measured and compared according to the measuring method. Water Vapor Transmittance (WVT) of the fabric woven by the sheath/core composite yarn in the warp direction was the highest due to the small staple fiber volume in the sheath/core yarn structure and high air voids in the sheath/core yarn fabrics. This property was also the highest in fabrics woven by bamboo staple yarns in the weft direction, and was the lowest on hi-multi filament fabrics. However, water vapor resistance ($R_{ef}$) of these fabrics by KSK ISO 11092 showed the opposite results to the water vapor transmittance method ($CaCl_2$ method); in addition, its correlation coefficient was low. The correlation coefficient between $R_{ef}$ and the drying rate was 0.719; therefore, the measurement mechanism of $R_{ef}$ is analogous to the drying property measurement. The thermal conductivity of the fabrics woven with compact staple yarn showed a high value; however, the hi-multi filament fabric showed low thermal conductivity. Therefore, fiber characteristics affect thermal properties more than yarn structure. The correlation between thermal property and moisture transport was also low. This study showed that: water vapor transmittance was active at the loose yarn structure, dry heat transport was vigorous at the compact yarn structure, and heat transport was affected more by fiber characteristics than yarn structure. In conclusion, sheath/core composite yarns were relevant to the high absorptive cool suit along with siro-fil and CoolMax/Bamboo staple yarns that were relevant to the heat diffusive cool suit.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.7-10
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• 2002

In this study, polyolefin compounds were developed and evaluated for replacing a jacket material of URD power cables. The characteristics of compounds were investigated by water vapor transmission (WVT) test and mechanical test. In WVT test, all polyolefin compounds showed the superior water resistance to conventional PVC. The molecular structure and density of polyolefin play an important role in WVT. Also, polyolefin compounds showed the suitable characteristics in mechanical test. Especially, polyolefin compounds having linear molecules showed the superior characteristics to LDPE ones. From this study, it can be considered that polyolefin compounds may be suitable to jacket material for URD power cables.