• Title/Summary/Keyword: Moisture condensation

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Efficient Drying Conditions for a Condensing Clothes Dryer (응축식 의류건조기의 효율적인 건조 조건)

  • Chung, Hae-Won;Kim, Hyo-Jeong;Hwang, So-Yeon
    • Fashion & Textile Research Journal
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    • v.10 no.6
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    • pp.1058-1063
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    • 2008
  • The use of clothes dryers is increasing in Korea and throughout Asia, because of preference for the drum type washer dryer. Clothes dryers consume more energy than almost any other home appliance. This paper suggests efficient ways for drying laundry with condensing clothes drier. We dried cotton fabrics with the condensing clothes dryers and observed the energy input, temperature and RH of the dryer during the drying process. In the early stages of drying process, the air temperature inside the clothes dryer decreased and the RH and the drying time increased as the weight of fabrics increased. We found that it was important to consider the total weight of the fabrics that included heat-sensitive fibers. It took more than half the drying time and the energy input for a 2.5 kg load that it did for a 5 kg load. Therefore, drying larger one load was more efficient than divided smaller loads, because increasing the weight of the fabrics reduced the energy input per kg of drying clothes. The lower the initial moisture regains of the fabrics were, the lower the energy input and the drying time were. The energy input for spinning after washing was much less than that for drying in the dryer. Consequently, it is more efficient to reduce the moisture content of the clothes by lengthening the spinning time of the washer to reduce the energy consumption and the drying time. During the drying process opening the door twice for 30 seconds each time lowered the air temperature and the RH of the dryer, but did not affect the moisture regain of the fabrics, the drying time, and the energy input.

Effects of Film Thickness and Moisture Absorbing material on Ginger Quality during MA Storage (필름두께 및 흡습제 처리에 따른 생강의 MA 저장효과)

  • 정문철;남궁배;김동만
    • Food Science and Preservation
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    • v.6 no.3
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    • pp.264-269
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    • 1999
  • The effects of film thickness and moisture absorbing materials(MAM) on the ginger qualities were investigated during MA storage for 150 days. LDPE films of 0.04, 0.06 and 0.08mm thicknesses were applied to select the adequate film in gas permiability. MAMs of sheet and sachet type were applied to 0.06mm-LDPE film bag to prevent moisture condensation during storage. Thickness of film used affected neither weight loss nor firmness of gingers during U storage. But the thinner in thickness showed the less changes in sprouting, spoilage and reducing sugar. Moreover, compared with MAP alone, MAPs with MAM of both sachet and sheet styles led to the weight loss of gingers increasing by more than 3-4 times, but sprouting rate, spoilage rate and reducing sugar decreasing by 3.3, 1.4 and 2.3 times, respectively. These results showed that MAP with UM was significantly effective to prolong the freshness of ginger by longer than 2 times, compared with MAP alone.

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A STUDY ON THE EFFECT OF MOISTURE ON APICAL SEALING PROPERTY OF ROOT CANAL (근관충전 시 수분오염이 치근단 폐쇄성에 미치는 영향에 관한 연구)

  • Lim, Sung-Sam;Kang, Myung-Whai
    • Restorative Dentistry and Endodontics
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    • v.21 no.2
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    • pp.628-634
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    • 1996
  • The purpose of this study was to investigate the effect of moisture on apical sealing properties of root canal. Fifty five single rooted human teeth were selected from maxillary and mandibular teeth. After removing crown portion at the cemento-enamel junction, all teeth were routinely prepared with step-back method. And then, the canals were dried with paper point and the teeth were randomly divided into 3 groups of 15 teeth each, and remaining 10 teeth were used as positive and negative control teeth : Group 1 were irrigated with 1ml of 95% alcohol and dried with air and paper point. Group 2 and 3 were intentionally contaminated with 0.05ml of 3.5% NaOCl or saliva, respectively. All the teeth were obturated with sealapex and gutta percha cone by lateral condensation technique, and covered with two coat of nail varnish after 48 hours of obturation. The teeth were immersed in india ink for 1 week and cleaned with methyl salicylate and then the degree of dye penetration were measured with stereomicroscope. The data were analyzed statistically by one-way ANOVA. The results were as follows : 1. All experimental groups showed varying degrees of dye penetration, and the mean degree of dye penetration was 0.1mm to 0.7mm. 2. Saliva contamination group(group 3) showed the highest amount of dye penetration, followed by NaOCl contamination group, then alcohol dried group, but there was no significant difference among three experimental groups. * This results suggest that there was no significant differences of apical leakage after canal obturation between alcohol dried canal and moisture present canals and the use of alcohol instead of paper point is unnecessary to dry the canals prior to canal filling. But other factors such as bacterial contamination and sealer discoloration by moisture must be considered in application of this results to clinical practice.

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A Study on Optimizing Drying Performance of Air Dryer (에어 드라이어 제습성능 최적화 프로그램 개발)

  • Park, Won-Ki;Lee, Hi-Koan;Yang, Gyun-Eui;Mun, Sang-Don
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.6
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    • pp.70-75
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    • 2010
  • Compressed air represents an energy source and an force-transmission medium for brake systems on medium-heavy and heavy-duty commercial vehicles. However, one disadvantage is the tendency of air to absorb moisture in the form of water vapor. This water vapor condenses once the air, which is heated during compression, cools back to ambient temperature upon emerging from the air compressor. The resulting condensation assumes the form of moisture in pneumatic lines, air tanks, cylinders and valve assemblies and can have negative consequences for the brake system and vehicle safety. The pneumatic systems on today's vehicles are equipped with air dryers, in which the supplied air is dried according to the adsorption principle. In the systems, the compressed air flows through a granular desiccant with molecular sieves which captures the water molecules.

The Generative Mechanism of Cloud Streets

  • Kang Sung-Dae;Kimura Fujio
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.1 no.2
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    • pp.119-124
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    • 1997
  • Cloud streets were successfully simulated by numerical model (RAMS) including an isolated mountain near the coast, large sensible heat flux from the sea surface, uniform stratification and wind velocity with low Froude number (0.25) in the inflow boundary. The well developed cloud streets between a pair of convective rolls are simulated at a level of 1 km over the sea. The following five results were obtained: 1) For the formation of the pair of convective rolls, both strong static instability and a topographically induced mechanical disturbance are strongly required at the same time. 2) Strong sensible heat flux from the sea surface is the main energy source of the pair of convective rolls, and the buoyancy caused by condensation in the cloud is negligibly small. 3) The pair of convective rolls is a complex of two sub-rolls. One is the outer roll, which has a large radius, but weak circulation, and the other is the inner roll, which has a small radius, but strong circulation. The outer roll gathers a large amount of moisture by convergence in the lower marine boundary, and the inner roll transfers the convergent moisture to the upper boundary layer by strong upward motion between them. 4) The pair of inner rolls form the line-shaped cloud streets, and keep them narrow along the center-line of the domain. 5) Both by non-hydrostatic and by hydrostatic assumptions, cloud streets can be simulated. In our case, non-hydrostatic processes enhanced somewhat the formation of cloud streets. The horizontal size of the topography does not seem to be restricted to within the small scale where non-hydrostatic effects are important.

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A Study on Removal Efficiency of VOCs using Vortex Cyclones (보텍스 사이클론을 이용한 VOCs 제거효율에 관한 연구)

  • Lim, Gye-Gyu
    • Applied Chemistry for Engineering
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    • v.16 no.2
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    • pp.194-199
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    • 2005
  • The principle of vortex cyclone was applied to enhance the treatment efficiency of waste air streams containing particulate matters, phenol, and others. Adsorption, condensation, and/or coagulation could be induced at low temperature zone formed by Joule-Thomson expansion as the pressurized air and pulverized activated carbon were introduced at the tangential direction into the cyclone system applied with the coaxial funnel tube of vortex cyclone. Easily condensible vapors were adsorbed and/or condensed forcibly on coagulated or condensed materials which were formed as cores for coagulation or condensation by themselves or on pulverized activated carbons. These types of coagulation or condensation rates were rapidly promoted by increase in their diameter. The maximum removal efficiency obtained from this experiment for the removal of carbon dioxide and phenol was about 87.3 and 93.8 percent, respectively. Phenol removal efficiency was increased with the relative humidities and enhanced by pulverized activated carbon added. The Joule-Thomson coefficients were increased with the pressure of air injected in the range of the relative humidities between 10% and 50%. It is believed that the moisture, particulate matters, and the pressure of the process air introduced could control the removal efficiency of VOCs.

Study on Performance of Lithium-Silicate Permeation and Changing Prosity Structure according to Water Content (수분의 함수율에 따른 공극구조의 변화와 리튬실리케이트의 침투성)

  • Kim, Kwang-Ki;Moon, Hyung-Jae;Kim, Jeong-Jin;Park, Soon-Jeon;Lee, Joo-Ho;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.769-772
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    • 2008
  • Pores can become factors of reducing the capacity of concrete by being path of degradation factors and moisture can fill up pores inside of concrete, so evaluating the effect of unidirectional permeability due to moisture on pore structure of concrete structure is very important. Therefore, the change of pore structure in cases of 0%, 40%, 60%, 80% and 90% humidity being maintained on test specimens and in case of Lithium Silicate, which is chemical compound, being coated were evaluated. As a result, the condensation due to moisture could be confirmed since unidirectional permeability was decreased and the density of Pore Structure was improved as the percentage of water content was being increased. And, solution-type Lithium Silicate fills up pores of sizes around 1$\mu$m in the condition of carrying water and improves the density but the range of capacity improvement due to osmosis will be limited according to functional conditions.

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Effect of Antistripping Agent on the Enhancement of Resistance to Moisture Damage of Asphalt Mixture (아스팔트 혼합물의 내수분손상 향상에 대한 박리방지제의 효과)

  • Lee, Eun-Kyoung;Choi, Sei-Young
    • Journal of Adhesion and Interface
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    • v.10 no.4
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    • pp.182-190
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    • 2009
  • In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.

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Temperature History of the Concrete for Retaining Wall Insulated with Double Layered Bubble Sheet in Summer (서중기 2중버블시트로 단열처리된 옹벽의 온도이력 특성)

  • Jung, Eun-Bong;Kim, Kyung-Hun;Jang, Deok-Bae;Kyung, Yeong-Hyeok;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.45-46
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    • 2012
  • This study is intended to use the insulation effect of the dual bubble sheet to review the freezing prevention capability of underground walls by pouring the dual bubble sheet on the retaining walls before the concrete pouring to contemplate the temperature profile for each area of installation and the area of non-installation of the dual bubble sheet, and as a result, the temperature of the concrete was heightened than the ground due to the insulation effect in using the bubble sheet.

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The Physical Properties of Cotton Fabric Pretreated with Skim Milk Powder (탈지분유 전처리에 의한 면직물의 물성)

  • Lee Su Min;Song Wha Soon
    • Textile Coloration and Finishing
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    • v.17 no.1
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    • pp.52-59
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    • 2005
  • The purpose of this study is to establish the scientific data of cotton fabric pretreated with skim milk powder and to improve the dyeability. The surface monophology, add on, whiteness, stiffness, air permeability, moisture regain and absorption of cotton fabrics were evaluated by varying concentration of SMP to get the optimal conditions in pretreatment. FT-IR of cotton fabrics pretreated with SMP were measured. Amino acid compositions, viscosity of SMP were evaluated. The K/S values by varying concentration of cinnamon cassia and subtract of dyed SMP-C were measured. I attempted to evalute the color fastness of untreated and AI. The results are as follow; The optimal concentration of SMP was 9%(w/v) to be pretreated with cotton fabrics. From FT-IR spectrum, formation of -NH$_2$ and -COOH was verified by SMP-C. Denaturalization of protein and condensation of carbohydrate, fat, etc. were found in a measurement of amino acid and viscocity. The K/S value of cotton fabrics pretreated with SMP was higher than that of untreated. Most of the color fastnesses were great.