• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.74-82
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• 1982

In the previous study, we have reported the effect of lowering water activity of sodium chloride, sugars and polyols. In this study, water activity($a_w$)of various model Preparations of Kamaboko was measured and ability of lowering $a_w$ of starch, glycine and sodium lactate was discussed. In addition, the aw measurements were also compared to the predicted values of au which were derived from the equation of Raoult's law and the linear slope method by Sloan ana Labuza. The effect of starch on lowering $a_w$ was very low, and glycine was more effective than starch. Sodium lactate was shown to be the most effective among humectants examined. When it was added by $7.5\%$, the $a_w$ of model Kamaboko A was reduced to 0.93-0.94. Generally, prediction by the equation of Raoult's law turned out to be useful for determining $a_w$ lowering effect of humectants, excepting sodium chloride and sodium lactate. The equation of regression derived from the least squares could be applied to Predicting au in the model Kamaboko.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.3
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• pp.173-179
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• 1990

The effect of a highly water absorbing polyacrylate polymer, commonly called K-sorb, at rates of 0.0, 0.05, 0.2, and 0.5% by weight on the water retention properties of three soils, and the longevities of these treatment effects were evaluated. Water retentions were measured for all the treatments by use of a pressure-plate extractor in the laboratory. Available water and three-phase distributions at moisture tensions of 0.01, 0.3, and 15b were calculated from water retentivity data. A randomized block experiment of Chinese cabbages was conducted to examine the effects and the longevities of the treatments(0.0, 0.05, 0.1, and 0.2%) on water retention of Jungdong sandy loam soil in the field. Water retentions for a loamy sand, sandy loam, and loam soil, treated with 0.2 and 0.5% K-sorb, were increased. K-sorb treatments were more effective in sandy soil than in loamy soils. Water contents for the 0.5% treatment were markedly greater than those for the 0.2% treatment at earth moisture tension. K-sorb only at a rate of 0.5% remained effective in water retention of each soil through repeated drying and wetting for 12 months. Duncan's multiple range showed 0.2% treatment was effective(at the level of 0.05) after 2 months but not after 10 months under field condition.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.180-180
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• 2021

가로수는 「도로법」 제11조에 따른 도로(고속국도를 제외한다)와 보행자전용도로 및 자전거전용도로 등 대통령령으로 정하는 도로의 도로구역 안 또는 그 주변지역에 심는 수목을 말하며, 도시의 가로수는 기후조절효과 및 대기오염 정화효과 등을 가질 뿐 아니라 도심지 내에 녹색을 도입하고 도시경관을 구성하는 주요 요소이다. 전국 각 시도에서는 가로수 조성사업을 지속적으로 추진하고 있다. 하지만 몇몇 도시에서는 적절하지 않은 가로수 관리로 인해 가로수가 말라죽는 현상이 증가하고 있다. 이에 가로수 고사 현상을 감소시키기 위하여 토양수분과 토양온도를 측정하여 가로수 피해와 연관성을 조사할 필요성이 있다고 판단하였다. 본 연구는 춘천시에서 진행하였으며, 일반 가로수와 현재 가로수 고사로 문제가 되고 있는 3 모니터링 지점을 선정하고, 토양수분 센서를 5, 15, 40 cm 깊이에 설치하였다. 센서를 이용하여 토양수분과 지온, EC 모니터링을 실시하였다. 토양수분 모니터링 자료를 활용하여 토층별 토양수분 소비량 산정을 하고, 현장 토양시료를 채취하여 물리·화학적 특성을 분석하였다. 또한 가로수 증발산량 산정 및 토층별 토양수분 소비량과 소비패턴을 비교하였다. 본 연구 결과를 향후 RZWQM(Root Zone Water Quality Model) 모델의 기초자료 및 시나리오 구성에 활용될 수 있으며, 모니터링 및 모델링 결과를 활용하여 가로수 및 도시 표토 기능 위협 요인을 분석에 활용 될 수 있다.

• Analytical Science and Technology
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• v.13 no.3
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• pp.332-337
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• 2000

The study on the nitrogen adsorption, surface properties and water adsorption capacity of the carbonaceous desiccants derived from phenolic resin was carried out. In the nitrogen adsorption study on the carbonaceous desiccants, Type II isotherm for each sample was obtained. Furthermore, the adsorbed volume decrease with water washing of the desiccant. The $S_{BET}$ of the carbonaceous desiccants was $648.7m^2/g$ before washing and $189.3m^2/g$ after washing, respectively. The morphology of needlelike formation before washing and spherical particle after washing with water were observed from SEM micrographs. Finally, from the water adsorption effects, the percentage of the water loading capacity was 25-63%, and the capacity was good at relatively low humidity.

• The Korean Journal of Ecology
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• v.26 no.3
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• pp.143-150
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• 2003

Korea has plentiful precipitation but rainfall events concentrate on several months of rainy season in her weather condition. Korea, therefore, experiences drought for a given period every year. Moreover the soil has usually low water holding capacity, as it is composed coarse particles originated from the granite. Response of several oaks and the Korean red pine (Pinus densiflora) on water stress showed that water budget was significant factor determining vegetation distribution. In addition, dehydration level due to cold resistance mechanism of several evergreen plants during the winter season was closely related to their distribution in natural condition. Experimental result under water stress showed that the Korean red pine was very tolerant to desiccation but the seedlings showed high mortality during the dry season. The mortality tended to proportionate to soil moisture content of each site. A comparison between soil moisture content during June when it is severe dry season and moisture content of the culture soil when the pine seedlings reached the permanent wilting point due to water withheld proved that high mortality during the dry season was due to water deficit. Water potential of sample plants measured during the exposure experiment to the air pollutant showed a probability that water related factors would dominate the occurrence of visible damage and the tolerance level of sample plants. In both field survey and laboratory experiment, plants exposed to air pollution showed more rapid transpiration than those grown in the unpolluted condition. The result would due to injury of leaf surface by air pollutants. Aluminum (Al/sup 3+/) increased in the acid soil not only inhibits root growth but also leads to abnormal distribution of root system and thereby caused water stress. The water stresses due to air pollution and soil acidification showed a possibility that they play dominating roles in inducing forest decline additionally to the existing water deficit due to weather and soil conditions in Korea. Sludge, which can contribute to improve field capacity, as it is almost composed of organic matter, showed an effect ameliorating the retarded growth of plant in the acidified soil. The effect was not less than that of dolomite known in widely as such a soil ameliorator. Litter extract contributed also to mitigate the water stress due to toxic Al/sup 3+/. We prepared a model showing the potential interaction of multiple stresses, which can cause forest decline in Korea by synthesizing those results. Furthermore, we suggested restoration plans, which can mitigate such forest decline in terms of soil amelioration and vegetation restoration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.139-147
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• 1981

In this study, by using Landrock method modified by Yokozeki (1973) and Koizumi (1980), water activity ($a_w$) of various model preparations of Kamaboko was measured and ability of lowering $a_w$ of humectants added such as sodium chloride, sugars and polyols was discussed. The results were as follows : 1 The effect of sodium chloride on lowering aw was the highest among all of examined. When $4\%$ sodium chloride as humectant was added to the model Kamaboko, the $a_w$ was reduced to 0.94 or below. 2. Among the sugars, glucose was so effective that it lowered $a_w$ to 0.96 by adding $10\%$, but it would cause browning reaction on the Kamaboko surface. 3. Glycerin was the most effective among the polyols. When it was added by $10\%$, the $a_w$ of Kamaboko was reduced to 0.95. 4. It was more effective to decrease $a_w$ to lower moisture content of model Kamaboko.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.88-96
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• 1983

The effect of lowering water activity of various humectants has been reported in the previous papers. In this study, that effect of humectants used in combination with each other was discussed. Additionally, the Aw measurements were also compared to the predicted values of Aw derived from the equation of Raoult's law and the linear slope method by Sloan and Labuza. Each mixed humectant was thought to be salted-out by the other, and thus Aw values were observed to be somewhat lower as the result in all model preparations. The effect of lowering water activity by NaCl was the highest, and the efficiency of reduction of Aw was decreased in the order of NaCl, sodium lactate, glycerin, propylene glycol and sorbitol when each of them was combinated with other humectants. Aw values calculated by the equation of Raoult's law were not agreed so well to the measured Aw, so it was likely not to be the useful method for predicting Aw values in mixed humectants to far as they have showed higher ability for lowering Aw in the previous papers. The equations of prediction were derived from Aw values to be measured actually in the model Kamaboko.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.325-330
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• 1989

This study was undertaken to assess the effects of seed treatment and soil moisture content on mesocotyl elongation in rice seedlings. The effect of the high temperature pre-treatment on the mesocotyl elongation was 7 times as great as the control (non treatment). The mesocotyl lengths were of maximum value at the 8％ soil moisture, but of minimum value at the 16％ soil moisture plot, showing decreasing trend of mesocotyl length as soil moisture increases. The mesocotyl elongations were much greater at the ABA treated plot than at the GA$^3$, IAA and Kinetin plots. The relationship between the mesocotyl and excised root elongations was not evident, but the weight of excised roots became heavier with longer mesocotyl length.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.320-329
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• 2009

The purpose of this study was reducing the moisture accumulation in a wall, which can threaten the structural safety of light-frame wall and make residential environment poor. For the purpose, the laboratory test was carried out with different wall assemblies. Vapor retarder and air gap for ventilation were added to the typical wall. The improved performance of the proposed walls was examined through the test with distinct difference of temperature and relative humidity between outdoor and indoor air conditions. Increased dampproofing performance of additional vapor retarder was effective on reduction of moisture transmission from inside the house into the wall. However, unexpected high relative humidity was shown in the wall with two additional vapor retarder because of excessive dampproofing performance or inadequate location of vapor retarder. And, the open air gap induced the moisture transfer from inside the wall into outdoor air by ventilation. If the alternative to the induction of moisture transmission from inside the house into the wall with open air gap can be found, moisture reduction effect of that will be increased obviously.

• Journal of the Korea Concrete Institute
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• v.22 no.2
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• pp.159-169
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• 2010

A multiphysics model analysis including moisture transport, heat transfer and solid mechanics and experiments on the normal and light weight concrete were carried out in order to study the effect of preabsorbed water in the light weight aggregates on the drying and shrinkage characteristics of concrete. Consequently, with fixed water-cement ratio, loss of water content of normal and light weight concrete were compared and the results showed that the lightweight concrete lost less moist than the normal concrete in early age and long term which was by moist supply effect. Accordingly, shrinkage strain size and distribution of lightweight concrete were decreased, and shrinkage reducing effect was efficient in early age with water cement ratio 0.3 and in both early age, and long term with water cement ratio 0.5. The comparison of analysis results and exaperimental results indicate that characteristic values of moisture transport and the relation humidity and shrinkage strain from this study are resonable for application for other differential shrinkage analysis in lightweight concrete.