• 한국화재소방학회논문지
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• 제23권5호
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• pp.17-23
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• 2009

콘크리트가 화재에 노출되면 콘크리트 표면에서의 수분뿐만 아니라 콘크리트 내부에서의 수분도 수분의 평형 및 전달조건에 의하여 증발이 발생된다. 수분의 평형조건은 재료의 자기이력거동으로 표현되는 물의 증발에 대한 수착등온선 관계로 설명된다. 본 논문은 화재시 콘크리트 부재 내부의 수분변화를 예측하고자 하는 것으로 부재 내부의 임의의 위치에서의 상대함수율을 산정하기 위하여 유한요소방식을 적용하였다. 또한 고온에서 콘크리트의 수분확산 특성치에 대해서도 모델식을 제시하였다. 이러한 해석기법의 정확성을 검증하기 위하여 실험데이터와 비교하였으며, 그 결과 수분증발로 인하여 수분이 감소되는 효과를 포함한 전반적인 부재 내부의 수분이동현상이 실제 실험데이터와 거의 유사하게 나타나는 것으로 확인되었다.

• 한국식품과학회지
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• 제29권5호
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• pp.1033-1037
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• 1997

마시맬로가 채워져있는 복합 초콜렛 제품에서 저장과정 중의 곰팡이 발생에 대하여 조사하였다. 곰팡이 발생의 원인을 알기 위하여 초콜렛과 마시맬로의 수분 흡습 곡선을 살펴 본 결과 마시맬로는 초콜렛보다 흡습성이 더 크게 나타났고 수분 활성도와 수분함량의 관계는 Kuhn의 식을 잘 적용할 수 있었다. 복합 초콜렛에서는 시간이 경과함에 따라 수분이 내부 마시맬로에서 외부 초콜렛으로 이동하므로 마시맬로의 수분 활성도는 시간에 따라 0.88에서 0.80까지 감소하였고 초콜렛의 수분 활성도는 0.22에서 0.76까지 증가하였다. 수분활성도 0.76은 내건성 곰팡이가 자랄 수 있는 수분활성도이므로 장기간 저장 중에 곰팡이가 발생할 가능성이 있다. $25^{\circ}C$에서 3달 동안 저장된 복합초콜렛의 표면에서 곰팡이의 성장이 발생되어 동정한 결과 오염된 곰팡이는 주로 Aspergillus repens이었다. 여러 수분 활성도에서 복합초콜렛에 A. repens를 접종하여 곰팡이가 발생할 때까지 배양하였다. $25^{\circ}C$에서 수분활성도가 0.73에서 0.95로 증가할 때 곰팡이 발생기간은 162일에서 15일로 감소하였다. 저장기간이 오래되어 곰팡이가 발생할 수 있는 것은 수분 이동으로 인하여 초콜렛의 수분 활성도가 증가하는 것으로 생각된다.

• 생약학회지
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• 제42권2호
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• pp.182-186
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• 2011

Houttuynia cordata Thunb.[H.cordata]belonging to Saururaceae, is a wild medicinal herb of perennial plants, and grows well in a place with a lot of shade and moisture. The medical action of H.cordata is reported to have an antitumer effect, toxicity-suppressive effect, antifungal effect, diuretic effect, and antioxidative action, but its effect hasn't been reported on cardiovascular diseases, such as ateriosclerosis and hypertension yet. This study intended to confirm the effect of the water extract of H.cordata on the migration and proliferation of rat aortic smooth muscle cells. Such results show that the water extract of H.cordata suppresses the migration and proliferation of rat aortic smooth muscle cells. It is believed that a useful clue will be offered later to the prevention of cardiovascular diseases such as ateriosclerosis and hypertension, and the development of their medicines on the basis of the fact.

• 한국연초학회지
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• 제28권1호
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• pp.31-35
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• 2006

In this study, the effects of the relative humidity and storage time of blended tobaccos at total blending silo on cut tobacco equilibrium moisture contents, leaf moisture contents and migration of casing materials of tobacco types were investigated. To maintain the cutting moisture content(21 $\pm$ 1 %), it is necessary to keep 75 % relative humidity at 28 $^{\circ}C$ at total blending silo. The moisture content of reconstituted tobacco sheet was changed from $13{\sim}14$ % to $19{\sim}21$ % within 2 h after preblending. The contents of glycerin and fructose of tobacco types followed by storage time after preblending were not changed significantly. From these results, it is suggested that 2 h storage time after preblending was sufficient to maintain physical properties of cut tobaccos and tobacco taste and fragrance.

• 한국토양환경학회지
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• 제4권2호
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• pp.103-111
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• 1999

본 연구는 지표면 부근의 함수율이 아주 작은 불포화대중 휘발성 유기화합물가스의 이동에서 토양흡착으로 인해 발생하는 지연현상을 수학적으로 정식화하였으며, 이의 적합성을 검토하기 위하여 모델토양으로 glass bead 또는 규사를 채운 칼럼실험을 수행하여 지연계수를 적용한 이론계산과 기존의 지연식을 적용하여 구한 계산결과와 비교하였다. 그 결과 불포화 다공대중에서의 TCE가스의 이동현상은 가스로 부터 토양으로의 흡착을 고려한 지연계수를 적용한 계산결과가 기존의 지연계수를 적용한 계산 결과보다 실험결과를 잘 재현함을 알 수 있었다.

• 동의생리병리학회지
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• 제25권3호
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• pp.425-430
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• 2011

This study evaluated the effect of extraction conditions of yam (Dioscorea aimadoimo) on antioxidant, moisturizing, collagenase activity, proliferation, and migration. Yam has been recognized as a healthy food due to its various biological activities, such as anti-obesity, anti-constipation, anti-mutagenic activities, as well as its ability to decrease blood glucose and cholesterol levels. Electron donating ability of high temperature ethanol extract of Dioscorea aimadoimo (HDA) had shown 70.6% at 400 mg/ml, and low temperature ethanol extract of Dioscorea aimadoimo (LDA) had shown 40% at 400 mg/ml. SOD-like activities of LDA and HDA were 23% and 34% at 400 mg/ml respectively. LDA significantly reduced the activity of collagenase in a dose-dependent manner, which was higher than HDA. The water contents in LDA-treated skin and HDA-treated skin were increased by 45.63% and 38.65% than the placebo cream respectively. The cellular proliferation of human dermal fibroblast neonatal (HDFn) was evaluated by MTT and cell migration assay. Compared to control, the cell proliferation was elevated to 109.7% and 114% by the treatment of LDA and HDA respectively at the concentration of 200 mg/ml. In addition, LDA and HDA were induced cell migration in HDFn. Our study suggests that LDA and HDA should be a very useful cosmetic ingredient, as anti-aging and skin moisturizer.

• 한국의류산업학회지
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• 제25권1호
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• pp.119-126
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• 2023

This study aimed to determine the effects of relative humidity and fiber properties on the moisture permeability of multilayer systems by measuring water vapor transmission in the overlapping condition of various fabrics. The results confirmed that the property of the fabric in contact with the humid environment affects the moisture permeability. If the layer facing the humid environment is hydrophobic and the layer facing the dry environment is superhydrophobic, water vapor transmission increases by up to 17.8% compared to the opposite conditions. Comparing the correction values of the water vapor transmission reflecting the thickness of the specimen under the multilayer condition showed that permeability was higher when the hydrophilic or hydrophobic layer was facing the humid environment. The opposite was true from the "push-pull" effect of absorption mechanism. In the case of moisture permeability, the more hydrophilic the surface facing the humid environment, the more permeable that water vapor diffuses and passes through. It was concluded that the "pull-push" effect, in which water vapor diffuses widely through the hydrophilic facing a humid environment and then passes through the hydrophobic layer, contributes to the improvement of permeability. Permeability differed according to the multilayer overlapping condition. When the relative humidity was high, the "pull-push" effect was insignificant. This is caused by water droplets absorption after the partial migration of water due to condensation. These results suggest that the overlapping conditions and properties of fabrics should vary depending on heavy sweating or not.

• 한국포장학회지
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• 제10권1호
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• pp.7-14
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• 2004

Migration behavior of selected solvents and food samples showed differences of the chemical structures and polarities, the food samples which have similar polar expresses more higher affinity than different polar degrees. Water which is polar has a highest partitioning coefficient values on polar isopropanol, and oil which is nonpolar has highest partitioning value on non-polar toluene. The increasing order of partitioning values was accord with increasing water contents in food samples. It is showed that the wheat flour with 13.2% moisture content has the highest partitioning coefficient values on the isopropanol with -OH. Kp value of sugar showed remarkable lower partitioning coefficient values than other food samples due to high degree crystallinity. This phenomenon can be predictable with ${\delta}$ values, because order of partitioning coefficient values which comes out through the experiment and the sequence of Hildebrand solubility parameter value difference between food sample and printing ink solvent correspond almost. This Hildebrand solubility parameter value can be easily applied to the food package industry because the effect of food-safety can be considered without passing through complicated steps by using this method.

• 한국농공학회지
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• 제35권4호
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• pp.47-54
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• 1993

A series of laboratory tests was performed with soil-columns which were compacted with sands and different amount of silt collected from the mid-stream of Gumgang, Korea. A known degree of concentration of PCP(Pentachlorophenol) was poured into the soil-columns and concentration of PCP was monitored and analyzed with time and depth. The results of the study are summarized as follows : 1. PCP was transported into soil along with the movement of moisture under gravitational force. The amount of PCP transported through soil or absorbed by soil varied with soil types. 2. The great amount of PCP was remained at 4~8cm section for the specimen No.2 and at 0~4cm section for the specimen Nos. 3 and 4. Based upon this result it is said that the amount of silt between 30 and 40% may be a threshold value for PCP transported through soil. 3. The amount of PCP remained in the specimen Nos. 2, 3 and 4 is greater than that in the specimen No.1 due to high specific surface of silt and high attraction force between PCP and silt particles in the specimen Nos. 2, 3 and 4. 4. It is said that groundwater under highly permeable soil layer such as specimen No.1 is easily polluted by PCP. That is because the PCP is basically migrated with water under the gravitational force.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.3-17
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• 2007

This paper provides an introduction to life-span simulation and numerical approach to support the performance design processes of reinforced concrete structures. An integrated computational system is proposed for life-span simulation of reinforced concrete. Conservation of moisture, carbon dioxide, oxygen, chloride, calcium and momentum is solved with hydration, carbonation, corrosion, ion dissolution. damage evolution and their thermodynamic/mechanical equilibrium. Coupled analysis of mass transport and damage mechanics associated with steel corrosion is presented for structural performance assessment of reinforced concrete. Multi-scale modeling of micro-pore formation and transport phenomena of moisture and ions are mutually linked for predicting the corrosion of reinforcement and volumetric changes. The interaction of crack propagation with corroded gel migration can also be simulated. Two finite element codes. multi-chemo physical simulation code (DuCOM) and nonlinear dynamic code of structural reinforced concrete (COM3) were combined together to form the integrated simulation system. This computational system was verified by the laboratory scale and large scale experiments of damaged reinforced concrete members under static loads, and has been applied to safety and serviceability assessment of existing structures. Based on the damage details predicted by the nonlinear finite element analytical system, the life-span-cost of RC structures including the original construction costs and the repairing costs for possible damage during the service life can be evaluated for design purpose.