• Title/Summary/Keyword: moisture effects

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Surface Modification of PET Irradiated by Ultra-Violet (Part II) - Transformation of moisture properties and physical Properties - (UV조사를 통한 PET의 표면개질(제2보) -수분특성 및 물리적 특성 변화-)

  • Choi Hae Young;Lee Jung Soon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.29 no.5 s.142
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    • pp.617-625
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    • 2005
  • The purpose of this study was to develop functional and environment-friendly polyester fabric by irradiating Ultra-Violet, which was produced by the low-pressure mercury lamp. UV irradiation was conducted with various treatment times and distances. Also, pretreatments of solvents and photoinitiator were used to improve the surface modification effects. The effects of UV irradiation on the moisture regain were found to increase gradually with increase of UV treatment time and decrease of treatment distance. Compared the effects of UVC and UVA, UVC was more effective than UVA. Moisture regain and wicking of PET was increased after UV treatment in our experimental condition. And owing to increasing of moisture regain, static charge was decreased. Pretreatment of solvents such as methanol, ethyl ether and addition of photoinitiator such as Benzophenone accelerated surface modification. The moisture regain was increased but wicking was decreased with pretreatment and addition of photoinitiatior. Therefore it is considered as inappropriate f3r clothing because of wicking effects. Yellowness, tensile strength and elasticity slightly decreased after UV irradiation.

Moisture Sensitivity and Aging Effects of Recycled Wastepaper fiber Cement Composites (폐지섬유보강 시멘트 복합체의 수분민감성 및 열화특성)

  • 원종필;배동인;박찬기;박종영
    • Journal of the Korea Concrete Institute
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    • v.14 no.2
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    • pp.148-155
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    • 2002
  • This research investigates the moisture and aging effects of wastepaper fiber-cement composites. Wastepaper fibers is obtained by a dry process. Wastepaper fiber-cement composites was manufactured by the hatscheck process. The effects of moisture and aging on the performance of wastepaper fiber-cement composites were investigated through accelerated laboratory tests simulating the effects of moisture sensitivity and wet-dry cycles as well as freeze-thaw cycles and long-term drying. They were shown to possess acceptable moisture and aging performance compared with virgin fiber cement composites.

The Effects of Heat Transfer Characteristics of Fibers on the Warm/Cool Touch of Insulating Nonwovens (섬유의 열전달 특성이 보온용 부직포의 접촉온냉감에 미치는 영향)

  • Kim, Hee-Sook
    • Korean Journal of Human Ecology
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    • v.8 no.1
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    • pp.125-134
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    • 1999
  • The purpose of this study was to investigate the effects of heat transfer characteristics of fibers on the Qmax of insulating nonwovens. The effects of fiber type, moisture content, washing cycles on the Qmax were observed. The correlations between Qmax measured by KES-F7 system and subjective warm/cool touch perception test was analyzed. The results obtained were as followed: 1. Heat transfer characteristics of fibers effected on the Qmax of insulating nonwovens. 2. Moisture transport properties of fibers effected considerably on the Qmax of nonwovens and the increasing rate of Qmax by increasing moisture content was much higher at wool than polyester. 3. As a result of subjective perception test, subjective warm/cool touch and wettness of wool nonwoven was increased obviously by increasing moisture content. 4. At the same moisture content, wool nonwoven showed higher subjective cool touch and wetness than polyester. 5. In the physical properties of nonwovens, thickness was the most effective factor on the Qmax of insulating nonwovens.

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Effects of the Moisture Contents of Cut Tobaccos on Loose End of Cigarettes (각초 수분이 궐련의 끝빠짐에 미치는 영향)

  • Yang Burm-Ho;Jung Han-Ju;Ahn Dae-Jin;Kim Yong-Ok
    • Journal of the Korean Society of Tobacco Science
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    • v.27 no.2
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    • pp.201-206
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    • 2005
  • In this work, we studied the effects of the moisture contents of cut tobacco on loose end of cigarettes. The loose end of the cigarette groups decreased with the increase of moisture contents of the cut tobacco and especially the loose end of A and C groups decreased to $31\%\;and\;52\%$ with the increase of $1\%$ moisture contents. $A-13.5\%\;and\;B-14.0\%\;and\; C-14.0\%$ moisture samples showed the increase of the weight ratio of cut tobacco over 1.4mm cut length but the decrease under 1.4mm cut length. We concluded that the main reasons were regarded to reduction of small fragment tobaccos caused by increase of moisture contents and exception of air-suction transport of tobaccos to cigarette making machine. In spite of the moisture increase of cut tobaccos under fixed EPD(encapsulated pressure drop), the hardness of Band C sample groups were maintained constantly except A group. This result means that under fixed EPD, the weight of cut tobacco in cigarette rods increases to compensate the reduction of pressure drop by moisture increase of cut tobaccos.

Effects of Moisture Content on Non-Fracture Dynamic Properties and Fracture Quality of Pacific Whiting Surimi

  • Esturk, Okan;Park, Jae-Won;Raik, Moo-Yeol;Kim, Byung-Yong
    • Food Science and Biotechnology
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    • v.15 no.6
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    • pp.856-859
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    • 2006
  • The effects of moisture content on non-fracture dynamic properties and fracture gel quality of Pacific whiting surimi were investigated to determine their relationships. Surimi samples were tested at various moisture contents (75, 78, and 81 %). Torsion test showed that shear stress decreased rapidly and strain values decreased gradually as moisture concentration increased. Dynamic storage modulus (G') also decreased as moisture content increased. A strong positive correlation ($R^2=0.90$ to 0.99) was found between the G' measured at temperatures between 10 and $45^{\circ}C$ and fracture stress values. The results indicate that dynamic rheological measurements could be used as a tool for early gel quality assessment.

Numeric simulation of near-surface moisture migration and stress development in concrete exposed to fire

  • Consolazio, Gary R.;Chung, Jae H.
    • Computers and Concrete
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    • v.1 no.1
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    • pp.31-46
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    • 2004
  • A methodology is presented for computing stresses in structural concrete members exposed to fire. Coupled heat and moisture migration simulations are used to establish temperature, pore pressure, and liquid-saturation state variables within near-surface zones of heated concrete members. Particular attention is placed on the use of coupled heat and multiphase fluid flow simulations to study phenomena such as moisture-clogging. Once the state variables are determined, a procedure for combining the effects of thermal dilation, mechanical loads, pore pressure, and boundary conditions is proposed and demonstrated. Combined stresses are computed for varying displacement boundary conditions using data obtained from coupled heat and moisture flow simulations. These stresses are then compared to stresses computed from thermal analyses in which moisture effects are omitted. The results demonstrate that moisture migration has a significant influence on the development of thermal stresses.

Moisture Absorption and Desorption Properties of Douglas Fir, Hinoki, Larch, Plywood, and WML Board in Response to Humidity Variation

  • PARK, Hee-Jun;JO, Seok-Un
    • Journal of the Korean Wood Science and Technology
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    • v.48 no.4
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    • pp.488-502
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    • 2020
  • In this study, the moisture absorption and desorption properties presented by the Health-Friendly Housing Construction Standards of South Korea were compared using the wood of three tree species (Douglas-fir, Hinoki, Larch) and two types of wood-based materials(Plywood, WML Board). The national standards for functional building materials present that the amounts of moisture absorption and desorption should be at least 65g/㎡ on average, respectively according to the test method under KS F 2611:2009. Therefore, in this study, the moisture absorption/desorption properties of materials with no treatment (Control), with punching, and with surface stain finishing and the moisture absorption/desorption property improvement effects of the treatments were compared and analyzed. According to the results of this study, it was evaluated that all five types of wood and wood-based materials tested did not satisfy the amount of moisture absorption/desorption of at least 65g/㎡, which is the performance standard for moisture absorption/desorption functional building materials, indicating that untreated wood and wood-based materials cannot be applied as functional finishing materials according to the Health-Friendly Housing Construction Standards. The surface stain finishing greatly reduced the moisture absorption and desorption rates of the materials, and the amounts of moisture absorbed and desorbed were also shown to decrease by at least two times on average. When the surfaces of the materials were punched with Ø4mm holes at intervals of 20 mm, the moisture absorption/desorption areas increased from 18% to 51%, and this increase was shown to be capable of increasing the amounts of moisture absorbed/desorbed by 29% on average at the minimum, and 81% on average at the maximum. The effects of punching were shown to be identical even in cases where the materials were stain finished. For the application of wood or wood-based materials as eco-friendly, health-friendly, and moisture absorption/desorption functional building materials hereafter, it is judged that new physical and chemical improvement studies should be conducted, and treatment methods should be developed.

Effects of Soil Moisture on the Growth of American Ginseng (Panax quinquefolium L.)

  • Li, Thomas S.C.;Berard, R.G.
    • Journal of Ginseng Research
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    • v.22 no.2
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    • pp.122-125
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    • 1998
  • Adequate available soil moisture level is considered to be one the most important components in growing high yields of good quality ginseng. Excessive soil moisture may promote stillborn fungal pathogens and cause serious diseases in ginseng fields. This study showed that soil moisture levels for optimum growth and health of ginseng varied with soil texture. Fifty- percent available moisture for sandy loam and 75% for silty loam are the best moisture levels for good growth and higher yield.

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The Effects of Screw Speeds and Moisture Contents on Soy Protein under Texturization Using a Single-screw Extruder (압출성형기의 스크류 회전속도와 원료수분함량이 대두단백질의 조직화에 미치는 영향)

  • Han, Ouk;Lee, Sang-Hyo;Lee, Hyun-Yu;Oh, Sang-Lyong;Lee, Cherl-Ho
    • Korean Journal of Food Science and Technology
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    • v.21 no.6
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    • pp.772-779
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    • 1989
  • The effects of screw speeds and moisture contents on the physical properties of texturized extrudate from isolated soy protein were examined by using a single-screw extruder. The screw speeds and moisture contents tested were in the range of 122-334 rpm and 20-35%, respectively, and die temperature were $90-145^{\circ}C$. The texturization characteristics such as nitrogen solubility index, integrity index, chewiness, density, rehydration ratio, and lightness after rehydration were appeared to be influenced by screw speed and moisture content. As the screw speed increased and moisture content decreased, die temperature, nitrogen solubility index, integrity index, lightness before and after rehydration were increased, while chewiness, density, water content of final extrudate wee decreased. The rehydration rate was changed drastically at the feed moisture content of 30% in particular. As the moisture content decreased, the air cell size became large and its number was increased. The effects of interaction between screw speed and moisture content of raw materials on the extrudate characteristics were tested by the analysis of variance.

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Effects of the Changes in Handsheet Structure on the Water Absorption and Moisture Absorption (수초지 구조변화에 따른 흡수·흡습 특성 변화 연구)

  • Sung, Yong Joo;Kim, Dong Sung;Lee, Ji Young
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.48 no.3
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    • pp.30-36
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    • 2016
  • This study was conducted to investigate the influence of the changes in handsheet structure by beating, wet pressing and the addition of wood flour spacer on the water absorption and the moisture absorption properties. The higher beating treatment of BKP resulted in the denser structure of handsheet samples, which leaded to the lower water and moisture absorption. The wet pressing showed the similar effects by reducing the bulk of handsheets. In case of the handsheet samples with similar bulk structure made of different beaten pulps, the severer beating treatment increased the water absorption and the moisture absorption. The addition of the wood flour spacer resulted in the higher bulk following the higher water and moisture adsorption. Since the water and the moisture absorption properties of paper products could greatly affect on not only the product quality but also the process runnability, the control of the water response of paper product has been considered as very important technology. The results of this study might be useful for control of water and moisture absorption properties of paper products.