• Geomechanics and Engineering
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• 제33권2호
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• pp.141-154
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• 2023

This study investigated the effect of water retention characteristics between aged and fresh Municipal Solid Waste (MSW) on the stability of the landfill. A series of transient numerical modeling for the slope of an MSW landfill was performed considering the variation of water retention characteristics due to leachate circulation. Four different scenarios were considered in this analysis depending on how to obtain hydraulic conductivity and the aging degree of materials. Unsaturated hydraulic properties of the MSW used for the modeling were evaluated through modified hanging column tests. Different water retention properties and various landfill conditions, such as subgrade stiffness, leachate injection frequency, and gas and leachate collection system, were considered to investigate the pore water distribution and slope stability. The stability analyses related to the factor of safety showed that unsaturated properties under those varied conditions significantly impacted the slope stability, where the factor of safety decreased, ranging between 9.4 and 22%. The aged materials resulted in a higher factor of safety than fresh materials; however, after 1000 days, the factor of safety decreased by around 10.6% due to pore pressure buildup. The analysis results indicated that using fresh materials yielded higher factor of safety values. The landfill subgrade was found to have a significant impact on the factor of safety, which resulted in an average of 34% lower factor of safety in soft subgrades. The results also revealed that a failed leachate collection system (e.g., clogging) could result in landfill failure (factor of safety < 1) after around 298 days, while the leachate recirculation frequency has no critical impact on stability. In addition, the accumulation of gas pressure within the waste body resulted in factor of safety reductions as high as 24%. It is essential to consider factors related to the unsaturated hydraulic properties in designing a landfill to prevent landfill instability.

• 한국식품조리과학회지
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• 제11권4호
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• pp.337-341
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• 1995

The effect of time and amount of water by conventional blanching method on the retention minerals in spinach and broccoli was investigated. The vegetables were blanched for 1, 2, 3 and 4 minutes, with 150 $m\ell$, 300 $m\ell$, 450 $m\ell$ of water for every 100 g of raw material. Blanching of spinach showed that Na was reduced remarkably after 2 minute of blanching, the others (K, Fe, Ca, Mg, P, Cu) were gradually decreased as the blanching time increased. Blanching of broccoli showed that the content of minerals were reduced remarkably after 1 minute of blanching. The longer blanching time further reduced the content of minerals. The retention of minerals (Na, K, Fe, Ca, Mg, P, Cu) in spinach and broccoli was reduced gradually as the blanching water increased. The retention rate of minerals were 12.7％ of Na, 37.4％ of K, 37.1％ of Fe, 43.9％ of Ca, 39.0％ of Mg, 53.5％ of P, 56.2％ of Cu in spinach and 21.0％ of Na, 41.3％ of K, 57.8％ of Fe, 38.8％ of Ca, 51.5％ of Mg, 57.7％ of P, 44.4％ of Cu in broccoli for 4 min, with water 450$m\ell$ every 100g of raw material.

• 복식문화연구
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• 제10권5호
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• pp.578-589
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• 2002

The purpose of this research was to analyze the residual water retention and to determine the number and species of microorganisms from the wet cotton fabrics in dehydration and drying process during washing. The drying rates of terrycloth and interlock knit under the rainy seasons were measured according to the dehydration and hanging methods, layers of fabric and pre-treatment agents. Microorganisms were isolated from the dried terrycloth by pure culture, and were identified by Biolog system. The results are as follow: The initial water retention of fabrics after dehydration decreased in the order of dripping>centrifuge>squeezing method, which affected the drying rate. The drying rates were faster by increasing surface area of fabrics. There was no significant difference in drying rate among the fabrics pre-treated with detergent, or fabric softener, or cationic surfactants such as Cetyltrimethylammonium bromide(CTAB) and Benzalkonium chloride(BC). Puedomonas aureginosa was found in the fabrics treated with a powder-type detergent. On the other side, there was no growth of microorganism in the fabrics treated with a liquid-type detergent (containing antibacterial agent), CTAB and BC.

• Archives of Pharmacal Research
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• 제20권6호
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• pp.637-642
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• 1997

Degradation of a compound with a hydroxyl group during the course of its diffusion across the skin was investigated. Based on the experimental findings of ashortened retention time of a degradant peak from post-diffusion samples and from the ability to evaporate radioactivity from such samples, it seems that during diffusion the parent compound degrades into a more hydrophilic product which is then oxidized. A tritium label at the carbon with a hydroxyl group was released as a tritiated water. When the post-diffusion samples were left open to the air allowing evaporation of water, there was a corresponding decrease in radioactivity of such samples. There was a linear relationship between the time left open and the fraction of radioactivity lost. When such samples were fractionated by HPLC, and then had their radioactivities measured by scintillation counting, two peaks wre identified. The first peak, which may be attributable to tritiated water, was eluted at the same retention time as the solvent front. The second peak eluted at the retention time of the parent compound. When the evaporation/loss of radioactivity experiment was repeated using a $^{14}C$-labeled compound there was no significant loss of radioactivity, indicating that the earlier loss with $^{3}H$-labeled compound was related to the formation and loas sof tritiated water.

• Nutrition Research and Practice
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• 제6권2호
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• pp.126-131
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• 2012

The purpose of this study was to determine the effects of beverage temperature and composition on weight retention and fluid balance upon voluntary drinking following exercise induced-dehydration. Eight men who were not acclimated to heat participated in four randomly ordered testing sessions. In each session, the subjects ran on a treadmill in a chamber maintained at $37^{\circ}C$ without being supplied fluids until 2% body weight reduction was reached. After termination of exercise, they recovered for 90 min under ambient air conditions and received one of the following four test beverages: $10^{\circ}C$ water (10W), $10^{\circ}C$ sports drink (10S), $26^{\circ}C$ water (26W), and $26^{\circ}C$ sports drink (26S). They consumed the beverages ad libitum. The volume of beverage consumed and body weight were measured at 30, 60, and 90 min post-recovery. Blood samples were taken before and immediately after exercise as well as at the end of recovery in order to measure plasma parameters and electrolyte concentrations. We found that mean body weight decreased by 1.8-2.0% following exercise. No differences in mean arterial pressure, plasma volume, plasma osmolality, and blood electrolytes were observed among the conditions. Total beverage volumes consumed were $1,164{\pm}388$, $1,505{\pm}614$, $948{\pm}297$, and $1,239{\pm}401$ ml for 10W, 10S, 26W, and 26S respectively ($P$ > 0.05). Weight retention at the end of recovery from dehydration was highest in 10S ($1.3{\pm}0.7kg$) compared to 10W ($0.4{\pm}0.5kg$), 26W ($0.4{\pm}0.4kg$), and ($0.6{\pm}0.4kg$) ($P$ < 0.005). Based on these results, carbohydrate/electrolyte-containing beverages at cool temperature were the most favorable for consumption and weight retention compared to plain water and moderate temperature beverages.

• 한국물환경학회지
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• 제21권1호
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• pp.52-58
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• 2005

The assessment on characteristics of hydraulic behavior and water quality variations of underground reservoirs of buildings were studied. Firstly, it was thought that underground reservoir capacities($m^3$) of buildings should be not determinated by the uniform and same methods but be estimated on the basis of the dwelling areas on dominated households and their residential characteristics, because these characteristics influence significantly on actual water usages and patterns of buildings. Secondly, it was likely that the average reduction rate of residual chlorine in underground reservoirs were affected from the their capacities, because the average reduction rate of residual chlorine in underground reservoirs under $1,000m^3$ was 43 percent, on the other hand, that rate of underground reservoirs over $1,000m^3$ was 60 percent. Thirdly, through the field investigation, the retention time of drinking water in underground reservoirs were in the range from 0.3 day to 3.9 day. In addition to, the average reduction rate of residual chlorine were depended largely on the retention time of drinking water. When the retention time was under 24 hours, the average reduction rate of residual chlorine was 45 percent, and in case of over 24 hours, was 49 percent. Fourth, water level in underground reservoirs was averagely varied in the range from 0.1 m to 2.65 m at the height of underground reservoirs. If considered actual height of underground reservoirs, 37.6 percent of the height of underground reservoirs was only used. Consequently, the frequency of the inflow and outflow of drinking water in underground reservoir were very increased, and had an effect on the reduction of residual chlorine. Lastly, the investigations on hydraulic structure characteristics of underground reservoirs inside showed the locations of inflow and outflow of drinking water almost were in the opposite direction. And some buildings had several baffles in the middle. Nevertheless, their installations had no beneficial for the improvement of water quality.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.117-120
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• 2009

It has been gradually increased with the use of resin based membrane forming agent for curing method, which plays a role in protecting moisture evaporation by forming resin membrane at the surface of concrete. In this paper, tests were carried out to examine moisture retention capability of cement mortar applying membrane forming agent. Dosages and types of the membrane forming agent were varied. It is found that sheet curing sealed with the surface of concrete closely has favorable moisture retention capability. However, the application of membrane forming curing method had superiority in moisture retention capability at early stage but at later age, its capability is deteriorated. Hence, further study regarding altering application method was necessary to secure enhanced moisture retention capability.

• 펄프종이기술
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• 제32권1호
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• pp.33-40
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• 2000

The effectiveness of silica-based microgels prepared through the reaction of sulfuric acid and sodium silicate as a component of Compozil system has been evaluated . Silica based microgels with better performance in retention and drainage than a commercial colloidal silica sol have been successfully prepared. Silica gels with the highest charge density were obtained when product pH was controlled to 9. And highly charged silica-based microgels showed greater retention and freeness performance than a commerical product. In particular the difference in retention, turbidity , and freeness between these microgels and a commercial product was eminent at low addition rate. The effects of reaction conditions including reaction temperature, process water quality and feeing rate on product efficiency in improving retention and drainage were also investigated and discussed.

• 한국환경과학회지
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• 제14권10호
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• pp.937-944
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• 2005

Presently, aquatic plants are used for the water purification in inland water. This study was carried out to investigate the water purification effect of aquatic plants, Oenanthe javanica and Typha angustata, The experiment was conducted in outdoor flowing water was conducted for ten days, Water quality was measured in terms of water temperature, COD(chemical oxygen demand), SS(suspended solids), Total N, Total P. The results of field experimentation showed that hydraulic retention time was the earliest in July and August 2003, and there were not any particular changes of monthly water temperature in inflow water and outflow water. As we look at the changes taken place in inflow water and outflow water throughout the whole experiment period, the change of water quality in summer was salient, especially SS removal ratio showed distinguished change as $25\%$, when the pebble filter and aquatic were attached to it. The removal rate of COD, total N total P were $14,7\%,\;8\%\;and\;9\%$, respectively. In relating the length of water extension to the change in water quality, the water quality tended to get lower generally in proportion to hydraulic retention time.

• 한국가금학회지
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• 제41권3호
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• pp.159-164
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• 2014

본 실험은 닭고기 가공 공장별로 침지냉각에 따른 닭 도체의 수분 흡수율 및 감소율 그리고 신선도를 측정 비교하여 품질의 균일화 제고를 위하여 실시하였다. A도계장과 B도계장 닭고기 가공 공장에서 1회 각 40수씩 3회에 걸쳐 총 240수에 대하여 수분 흡수율 및 신선도를 측정하였으며, 수분 흡수율 실험이 완료된 도체에 대하여 개체 포장, 운송하여 실험실 냉장고($4{\pm}1^{\circ}C$)에 입고 후, 저장일별 수분 감소율 및 신선도를 측정하였다. 실험 결과, 수분 흡수율은 A도계장 4.8%, B도계장 4.2%로서 유의적인 차이는 발견되지 않았다. B도계장 실험 도체의 신선도가 냉각 전후 모두, A도계장 실험 도체보다 신선도가 유의적으로 높게 조사되었다. 저장일별 수분 감소율은 A도계장 실험 도체와 B도계장 실험 도체 사이에 유의적인 차이는 나타나지 않았다. 저장일별 신선도는 A도계장 실험 도체가 B도계장 실험 도체에 비해 낮게 조사되었다. 결론적으로 수분 흡수율은 chiller의 길이나 침지시간에 크게 영향을 받지 않으나, 수분 감소율은 침지 시간, 수온 및 심부 온도의 영향을 받는 것으로 예측되었다.