• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.4
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• pp.485-492
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• 2019

In this study, the effect of moisture conditions of recycled coarse aggregates on the compressive strength of concrete was evaluated with the water/binder ratios and the curing conditions. The saturated recycled aggregates seemed to have the negative effect on the strength development of concrete. This is the because of the decrease in bond strength between aggregate and cement paste due to the increase of surface water according to the high absorption of recycled aggregates. The effect of types and moisture conditions of aggregates according to the change of water/binder ratio was similar. However, the curing conditions had a significant effect on the compressive strength of the concrete with the different types of aggregates. In the case of curing in air, the recycled aggregates with high absorption reduced the moisture required for hydration and increased the rate of vaporizing, and these result in interfering strength development. The moisture conditions of the recycled aggregates have a considerable effect on the compressive strength of the concrete, and it is necessary to control the moisture conditions of aggregates in the production of concrete with recycled coarse aggregate. And the control of the curing condition is very important for the concrete with recycled aggregate.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.41-42
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• 2001

The objectives of this study were to investigate the effect of the physical properties of wick on the water absorption of substrate. Physical properties of wick in this study were cotton composition, width and length. The water Infiltration rate through the wick was 0.24 ㎝/s at 90 -95% cotton content, which was faster than at 80-85% (0.13 cm/s) and 70-75% (0.08 cm/s). As the cotton content increased, the water absorption of substrate became greater : the amount of absorbed water was about 5-7g higher at 90-95% than at 80-85% and 70-75% at a wick width of 1 ㎝, the velocity of water absorption through the wick was fastest with 0.25 ㎝ㆍs/sup -1/. The amount of absorbed water was higher at 3 ㎝ than at 1 and 2 ㎝. However, the water absorption rate through the cross - sectional area of wick (g H₂O /㎠/hr) was higher at a wick width of 2 ㎝ than at those of 1 and 3 ㎝. The amount of absorbed water in the substrate was higher at 2 : 1 than at 1 : 1 (length in substrate : length out of substrate). Absorbed water amount was larger at 30-40% initial moisture content than any other treatment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.1
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• pp.53-58
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• 2000

In this paper, the variable mechanical strength and dielectric breakdown strength of epoxy composites were measured at boiling absorption condition in order to observe the influences of moisture in out door use. Also, in order to improve water resistance of matrix resin, IPN(interpenetrating polymer network) method which had been already reported, was introduced and the influence was investigated. As Adding filter(SiO2) classified by o[phr], 50[phr] and 100[phr] to two kinds of matrix resin, six kinds of specimens were manufactured. As a result, it was confirmed that the moisture absorption rate was increased and mechanical strength and dielectric breakdown strength were degraded with boiling time and filler content increasing. On the other hand, it was confirmed that moisture absorption rates were decreased and the degrading rates of mechanical strength and dielectric breakdown strength were lowered according to improvement of adhesion strength in case of IPN specimens.

• KSBB Journal
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• v.28 no.5
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• pp.319-326
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• 2013

This study was carried out to investigate the in vitro and in vivo moisturizing properties and percutaneous absorption of PEG-impregnated Aloe vera gel. The PEG-i-Aloe gel was obtained from dewatering and impregnation by soaking (DIS) of Aloe vera leaf slice. The moisturizing property of the obtained sample was evaluated by moisture determination using gravimetric method in desiccator under different RH% and by water sorption-desorption test on human skin. The transdermal penetration characteristics of PEG-i-Aloe gel was investigated by Franz diffusion cell in vitro transdermal absorption method. PEG-i-Aloe gel had high moisture retention ability and could significantly lead the enhancing skin hydration status as well as reducing the skin water loss due to the film formation as a skin barrier. The skin penetration rate of PEGi- Aloe gel at steady state was 9.76 ${\mu}g/(h{\cdot}cm^2)$ and the quantity of the transdermal absorption was 144 ${\mu}g/cm^2$ in 9 hr. The penetration mechanism was well fitted with Higuchi model ($R^2$ = 0.974-0.994). The results show that PEG-i-Aloe gel has the significant moisturizing effect and strong penetration of the animal skin. It could be used as the moisturizing additive in cosmetic skin products.

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.358-368
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• 1994

Major factors in reducing the stacking strength of corrugated fiberboard boxes in cold storage or transport conditions are high relative humidity, causing elevated moisture absorption by the boxes. The bottom boxes in a stack will deform to the critical deflection causing agricultural products damage there, and eventually additional deflection will cause box collapse and finally toppling of the stack. The study was conducted to determine the water absorption characteristics and the compressive strength of the corrugated fiberboard boxes being widely used in packaging agricultural products in Korea. The sample boxes for the study were selected from the regular slotted containers (RSC) types, and one was the box used in apple packaging (Box A), another one was the box used in pear packaging (Box B). The corrugated shipping containers were made from a large portion of recycled fibers in Korea, and comparing with Box B, Box A was fabricated from fiberboard which contained more percentage of old corrugated containers (OCC) imported from foreign countries than domestic waste paper. The results obtained from the study were summarized as follows ; 1. Equilibrium moisture content (EMC) of the sample boxes was established after about 20 hours, and the EMC by absorption was lower than that by desorption. The EMC increased with the increasing of relative humidity and with the decreasing of temperature, and the rate of increasing was much higher above the relative humidity of 50%. 2. The maximum compressive strength of Box A was about 100 kgf greater than that of Box B on the same enviromental conditions. The strength of the sample boxes decreased rapidly with the increasing of relative humidity. The effect of relative humidity on the strength was a little higher than that of temperature. 3. As the applied load was progressively increased and a level was reached, the vertical side panels ($L{\times}D$) deflected laterally inwards or outwards. The panels deflected laterally inwards at higher relative humidity. 4. The maximum compressive deflection ratio and the critical deflection ratio of the sample boxes were increased linearly with the increasing of relative hunidity, but trends for its ratios showed inconsistant response to temperature.

• Composites Research
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• v.34 no.3
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• pp.174-179
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• 2021

Currently, fluid transfer steel pipes take a lot of time and expense to maintain all facilities due to new construction and painting or corrosion and aging. Therefore, this study was conducted for designing a CFRP pipe structure with high corrosion resistance and chemical resistance as a substitute for steel pipes. The helical/hoop pattern was cross-laminated to improve durability, and HNT was added to suppress the moisture absorption phenomenon of the epoxy. The HNT/CFRP pipe was manufactured by a filament winding process, and performed a mechanical property test, and a moisture absorption test in distilled water at 70℃. As a result, the highest bending strength was obtained when the hoop pattern was laminated with a thickness equivalent to 0.6% of the pipe. The 0.5 wt% HNT specimen had the highest moisture absorption resistance. Also, the delamination phenomenon at the interlayer interface was delayed, resulting in the lowest strength reduction rate.

• New & Renewable Energy
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• v.9 no.3
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• pp.29-35
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• 2013

This research analyzed the fuel characteristic change of spent coffee bean by torrefaction. The calorific value was increased from 4,974 kcal/kg to 6,075 kcal/kg ($260^{\circ}C$, 30min), 6,452 kcal/kg ($270^{\circ}C$, 30min), 6,823 kcal/kg ($280^{\circ}C$, 30min), 6,970 kcal/kg ($260^{\circ}C$, 30min). The highest energy yield was obtained when the spent coffee bean were torrefied on the condition of $280^{\circ}C$, 30min. The moisture absorption rate was decreased from 5.12% to 2.76% when the spent coffee bean were torrefied on the condition of $290^{\circ}C$, 30min. Lignin was increased from 11.33% to 14.39% on the condition of $260^{\circ}C$ 30min. But it did not preferability to torrefy spent coffee bean at temperature of more than $270^{\circ}C$ because lignin decreases to the level that is hard to make pellet.

• Journal of the Korean Home Economics Association
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• v.37 no.12 s.142
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• pp.193-203
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• 1999

This study was executed to show influence of material and property of sportswear to physiological responses of body and comfort sensation and to supply basic research data about comfortable sportswear Trainning wear was manufactured with cotton(C) and hygroscopically treated polyester material (FP), and its properties of material were measured. Then rectal temperature, skin temperature, heart rate, weight loss, clothing microclimate and subjective sensation was estimated with study of wearing with these sportswear and examined the influence that it got to physiological responses of body and sensation. Health adult men were selected for subjects and executed at climatic chamber of temperature, $20\pm2^{\circ}C and humidity, $60\pm5%$ R.H. Conclusively sportswear of hygroscopically treated polyester is a favorable functional material. So far factor that affect to physiological comfort sensation has been explained mostly by moisture regain but in our experiment, it turned out that air permeability, water absorption velocity and dynamic oater absorption etc. were affecting factors. So according to this result, air permeability and moisture permeability should be considered with transmittance of temperature moisture for development of comfort material.

• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.7-14
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• 2003

Absorption potential of desiccant solution significantly decreases after absorbing moisture from humid air, and a regeneration process requires a great amount of energy to recover absorption potential of desiccant solution. In an effort to develop an energy efficient regenerator, this study examines a regeneration process using hot air heated by solar radiation to recover absorption potential by evaporating moisture in liquid desiccant. More specifically, this study is aimed at finding the optimum operating condition of the regenerator by utilizing a well-established statistical tool, so-called response surface methodology(RSM), which may provide a functional relationship between independent and dependent variables. It is demonstrated that an optimization model to find the optimum operating condition can be obtained using the functional relationship between regeneration rate and affecting factors which is approximated on the basis experimental results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.103.2-108
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• 2003

The purpose of this study is to understand the Physical characteristics of cement mortar about humidity control on indoors and wall crack restraint. Experiments were conducted on the strength, water absorption coefficient, drying-shrinking crack, length change, cracks of mortar plaster bases according to mixture rate by mixing cellulose fiber and diatomite into cement mortar. The excellent tensile & bending reinforcement efficiency of cellulose fiber and void filling ability of diatomite proved to be suppressing cracks of cement. And diatomite seems to improve moisture-protection efficiency of cement mortar because of its high water absorption ratio and slow drying speed.