• 한국환경보건학회지
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• 제22권3호
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• pp.49-55
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• 1996

Water parsley(Oenanthe javanica(Blume) DC) was raised with varying population density(S) in the laboratory aquarium unit to determine the growth equation. The population density was measure after 7 days. The resultant growth curve was well fit to the equation 1/S = A+B (1/S0) with a high correlation coefficient ($R^2$ = 0.999). The maximum specific absorption rate was $9.011 \times 10^{-5}$ kg $NO_x-N/kg$ water parsley$\cdot$day and $1.31 \times 10^{-5}$ kg $PO_4-P/kg$ water parsley$\cdot$day when the average population density was $2.62 kg/m^2$. The relationship between population density and nutrient absorption rate, the absorption rate of $NO_x-N$ was 5.04~5.24 mg/l$\cdot$day when the population density was $7.51~10.0 $mg/m^2\cdot day$ and the absorption rate of $PO_4-P$ was 0.56~0.78 mg/l$\cdot$day when the population density was 5.02~10.0 $kg/m^2\cdot day$. Taking into account the nutrient absorption rate and growth rate, the population density between $7.0 kg/m^2\cdot day$ and $8.0 kg/m^2 \cdot day$ was selected. The removal rate of nutrient was investigated after 7 days culture. Removal rate of $NO_x-N$ was 95.6~99.95% with initial concentration of 35 mg $NO_x-N/l$, and the removal rate of $PO_4-P$ was also high, indicating 80.24~98.9% with initial concentration of 5.95 mg $PO_x-P/l$.

• 설비공학논문집
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• 제16권1호
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• pp.26-33
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• 2004

In general, an absorption chiller or heat pump is operated under the constant cooling water flow rate condition even though the system works with a partial load. The objective of this paper is to study the effect of the cooling water flow rates and the temperature of cooling water on the system performance to find the energy saving methode for the partial load operation of the double effect $H_2O$/LiBr absorption chiller. It is found that the performance of the system is sensitive to the temperature of cooling water than the cooling water flow rate, so the decrease of the performance due to reducing the cooling water flow rate can be overcome with the reduction of the cooling water temperature by 1$^{\circ}C$. The flow rate of the cooling water flow rate ranges from 50％ to 100％ of the flow rate at normal conditions with a partial load. It is also found that the operation cost of the cooling water pump and the cooling tower can be reduced by 23％.

• 한국의류학회지
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• 제24권6호
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• pp.810-818
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• 2000

The purpose of this study was to analyze the effect of geometrical structure on the moisture transport properties of nonwoven batting materials. Two types of nonwovens were used such as single and double layered nonwovens. Steady and dynamic state water vapor transport properties were measured by absorption, evaporation and cobaltous chloride method respectively. The results of this study were as follows: 1) Geometrical structure affected water vapor evaporation, but there were no differences between single and double layered nonwovens in moisture absorption. Thickness and air permeability were influencing factor on water vapor transport rate. 2) Directionality of double layered nonwoven was observed both in steady and dynamic state moisture transport. There were differences between upper and lower layer of double layered nonwoven both in moisture absorption rate and color change by cobaltous chloride method. 3) In dynamic state of water vapor transport rate, single layered nonwoven reached more rapidly at the established relative humidity. It was confirmed that geometrical structure affected water vapor evaporation and hydrophilicity of fiber affected moisture absorption because there were much more water vapor transport rate by evaporation than absorption within the same period of time.

• 한국재료학회지
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• 제27권8호
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• pp.451-458
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• 2017

The service life of coal gangue concrete(CGC) strongly depends on the capillary water absorption, this water absorption is susceptible to freeze-thaw cycles. In this paper, the cumulative water absorption and sorptivity were obtained to study the effects of 0, 0.5, 1.0, and 1.5 % steel fiber volume fraction added on the water absorption of CGC. Sorptivity and freeze-thaw tests were conducted, and the capillary water absorption was evaluated by the rate of water absorption(sorptivity). Three prediction models for the initial sorptivity of steel fiber reinforced coal gangue concrete(SFRCGC) under freeze-thaw cycles were established to evaluate the capillary water absorption of SFRCGC. Results showed that, without freeze-thaw cycles, the water absorption of CGC decreased when steel fiber at 1.0 % volume fraction was added, however, the water absorption increased with the addition of 0.5 or 1.5 % steel fibers. Once the SFRCGC specimens were exposed to freeze-thaw cycles, the water absorption of SFRCGC significantly increased, and 1.0 % steel fiber in volume fraction added to CGC caused the lowest water absorption, except for the case of the sample without steel fibers added. The CGC with steel fiber at 1.0 % volume fraction performed better. The SFRCGC has a strong response to freeze-thaw cycles. Results also showed that the linear function prediction model is practical in the field of engineering because of its simple form and a relatively high precision. Although the polynomial prediction model presents the highest computation precision among the three models, the complicated form and too many coefficients make it impractical for engineering applications.

• Journal of the Korean Wood Science and Technology
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• 제18권2호
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• pp.36-48
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• 1990

This experiment was carried out to improve the quality of high absorbent polymer which has excellent absorptivity and water retention compared to pulp and absorption sheet, through absorption characteristics-absorptive power, water retention, absorption rate, gel strength, pH, particle size, and moisture content. - of six polymers, namely, anionic polyacrylamide, cationic polyacrylamide, polyacrylic, acid polyvinyle alcohol 500, and 1500, and a-cellulose. and to examine the possibility of substitution of amide groups for carboxyl group and/or hydroxyl group which were commercial high absorbent polymer by comparing the absorption characteristics of the polymers. Polyacrylamide has high absorptive power and water retention, but has low gel strength and poor absorption rate. The rest of polymers were similiar to ${\alpha}$-cellulose in every respect. Thus, polyacrylamides could be replaced with polyacrylic acid and polyvinyl alcohol which are presently a high absorbent polymers. In comparing the absorption characteristics and the absorptive power of the polymers-anionic polyacrylamide, cationic polyacrylamide, polyacrylic acid, polyvinyle alcohol. a-cellulose-the absorptive power was in inverse proportion to the gel strength and absorption rates, affected by the particle size and pH change.

• 대한가정학회지
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• 제23권1호
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• pp.11-17
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• 1985

This paper aims to examine the variety of the absorption of cotton, T/C and hemp fabrics seperately seperaterly sized by rice, wheat, potato, corn flour and pp.V.A.. Experimental variables occurring in the concentration of sizing agents, the water content of unsized fabrics and an iron temperature show the following results, 1. When fabrics sized, the rate of absorption increases according to the order of rice, corn, pp.V.A., potato, wheat flour for cotton fabrics, of rice, corn, pp.V.A., wheat, potato flour for hemp fabrics and of the rice, pp.V.A., potato, corn, wheat flour for T/C fabrics : rice flour shows an absorption rate highest among all the others mentioned above. 2. To a certain extent, the stronger the concentration of sizing agents, the higher the rate of absorption. 3. The higher fabrics density, the higher absorption rate. 4. The structure and hydrophilic property of the sized fabrics affect the rate of absorption. 5. The fabrics with water content of 20% before sizing it shows the rate of absorption highest. 6. An iron temperature after sizing fabrics shows the rate of absorption highest at the properest at the properest one : $180^{\circ}C$ for cotton, $150^{\circ}C$ for T/C and $200^{\circ}C$ for hemp fabrics.

• 한국가구학회지
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• 제27권2호
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• pp.91-95
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• 2016

This study was conducted to investigate the relationship between water absorption (or hygroscopic property) and growth rate of rubra oak (Quercus rubra) from 5 different origins of seed (Carleton, Simcoe, Chatham, Bancroft, Unknown). Water absorption at cross section of Quercus rubra was $0.43{\sim}0.92g/cm^2$ and the property was not related with growth rate. Overall equilibrium moisture content of rubra oak were 11.35~11.56% and 15.15~15.83% at $40^{\circ}C$ with 75% and 90% relative humidities, respectively. There was no relationship between growth rate and moisture content(hygroscopy) in rubra oak. Based on the results, Rubra oak can be classified as a low hygroscopic wood grade, and thus might be a good raw material for furniture productions owing to its superior dimensional stability.

• 한국결정성장학회지
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• 제21권2호
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• pp.82-86
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• 2011

인공경량 골재는 다결정질 소성체를 주 구성으로 하므로 골재 내부에 다량의 공극이 일정비율로 형성되는 것이 특징이다. 이러한 인공경량 골재는 조직 구조의 특성상 외부환경의 변화에 의해 수분이 비정상적인 이동을 보이는 경향이 있다. 다공질 재료의 수분 방출 특성은 일반적으로 기공률 및 기공크기 분포에 크게 좌우되지만, 인공적으로 소결 제조된 경우에는 표면에 생성된 치밀한 구조의 표피층에도 많은 영향을 받을 것으로 생각된다. 인공경량 골재 내부의 수분 이동에 미치는 요인은 골재내의 세공 및 공극의 분포와 형상, 크기, 그리고 프리웨팅 방법 등이 있으며 각 조건에 따라 상당한 차이를 보인다. 본 연구에서는 인공경량 골재를 제조하여 골재의 가압시 흡수 특성이나 침수시간에 대한 흡수율의 거동에 대한 명확한 규명을 함으로써 경량골재 펌프압송을 위한 기초적 자료를 제공하고자 하였다. 본 실험에 사용된 인공경량골재는 독일 'L'사의 상업용 인공경량골재와 본 연구팀이 제조한 2가지 조성의 인공경량골재를 사용하였으며, 골재 수분함침시간, 진공압력, 급냉조건을 변화시켜 골재의 흡수율을 측정하였다. 인공경량골재를 $300^{\circ}C$ 에서 급냉 하였을 경우 24시간 침수보다 높은 흡수율을 보였고, 진공압력에 따라 흡수율이 증가하는 경향이 있으며, -300 mmHg의 진공 압력시 24시간 침수보다 "L"사 골재는 54 %의 높은 증가를 보였으나 K622와 K73 골재는 비교적 적은 2 % 내외의 흡수율 증가양상을 보였다.

• 한국태양에너지학회 논문집
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• 제24권1호
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• pp.53-61
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• 2004

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 efficient solar water heater, this study examines a regeneration process using hot water obtained from solar water heater to recover absorption potential by evaporating moisture in the liquid desiccant. In this paper, a solar absorption dehumidifying system with solar water heater is suggested to save the electricity for operating an air conditioner. LiGl(lithium chloride) solution was adopted as a liquid desiccant in the proposed system, and hot water obtained from the solar water heater was used for regenerating the liquid desiccant. As a result, it was clear that the dilute LiCl solution could be regenerated by hot water, and the regeneration rate depends mostly on temperature level of liquid desiccant. The regeneration rates were about 2.4kg/h with $40^{\circ}C$, 4.0kg/h with $50^{\circ}C$, and 6.2kg/h with $60^{\circ}C$ of hot water respectively.

• 대한기계학회논문집B
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• 제26권9호
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• pp.1241-1248
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• 2002

Performance extension of the absorption refrigerator with LiBr solution is often faced to operate very close to the crystallization limit. Especially in the development of an air-cooled cycle, the crystallization of working solution in the system is a very difficult problem to overcome. This paper describes the cycle of hot water driven absorption system using a new working absorption solution instead of LiBr solution to improve the efficiency. In this study, we found out the characteristics of new working absorption solution through the cycle simulation and compared LiBr solution to evaluate. The effect of cooling water temperature, weak solution flow rate, hot water temperature and hot water flow rate were also examined. The COP is increased 22% higher in the case of LiBr＋Li1＋LiC1＋LiNO$_3$＋$H_2O$, 2% LiBr＋HO(CH$_2$)$_3$OH＋$H_2O$ than that of LiBr solution for the same operation condition.