• Journal of Biosystems Engineering
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• v.15 no.4
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• pp.328-338
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• 1990

The objective of this study was to develop automatic systems of nutrient solution management for optimal nutrient solution environment and labor saving in water culture which enables factory crop production. In this study, an automatic control system and its driving program are developed to prepare, supply, and recover nutrient solution and to keep the optimal solution concentration level using microcomputers. Based on this study, the following conclusions are obtained: 1. The concentration measured by the system using oscillating circuit designed and built in this study, gave good agreements with the actual nutrient solution. 2. In water culture, the period of 12 hours for measuring concentration, pH, and temperature of the nutrient solution was optimum. Addition of control solution due to the decrease of the nutrient solution concentration is required in every 3 to 5 days. 3. It is estimated that the period of the whole solution change is 15 days, however, further research is needed to assure it. In addition, this period must be shortened in the future. 4. Both the hardware and software of the developed optimal nutrient solution control system in the water culture are working very well, however, it is necessary to develop a more economical one-chip micro controller to substitute for the microcomputer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.1034-1041
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• 2001

A numerical model which simulates the flow boiling process of the ammonia/water solution within a plate type generator for ammonia/water absorption refrigerators was developed. The ammonia/water solution flows downward under gravity and the ammonia/water vapor generated by flow boiling flows upward. The heating medium flows counter to the ammonia/water solution. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phases were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the heating medium inlet temperature, the mass flow rate of the heating medium and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

• Journal of Pharmaceutical Investigation
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• v.16 no.2
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• pp.43-54
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• 1986

To increase the bioavailability of clonixin, clonixin argininate was prepared and compared with clonixin by determining solubility, pKa, lipid-water partition coefficient, dissolution rate and in vivo tests. The results are summerized as followings; 1) The solubility of clonixin argininate was increased by 20 times in water, about 1.2 times in pH 1.2 and pH 8.0 buffer solution, and about 1.8 times in pH 6.8 buffer solution compared with that of clonixin. 2) pKa values of clonixin, clonixin lysinate and clonixin argininate were 6.32, 7.20 and 7.45, respectively. 3) The lipid-water partition coefficient of clonixin argininate was increased more than that of the clonixin in n-hexane, carbon tetrachloride, chloroform, methylene chloride, and n-butanol, but the partition coefficient of clonixin was increased more than that of clonixin argininate in benzene/pH 1.2 buffer solution, ether/pH 8.0 buffer solution, and 3-methylbutyl acetate/pH 1.2, pH 8.0 buffer solution. 4) The time required to dissolve 60% $(T_{60%},\;min.)$ of clonixin argininate was about 1.5 min. in water and pH 1.2 buffer solution, and about 5 min. in pH 6.8 buffer solution. $T_{60%}$ of clonixin lysinate was about 1.5 min. in water, about 1.8 min. in pH 6.8 buffer solution, and about 8 min. in pH 1.2 buffer solution. But $T_{60%}$ of clonixin was about 96 min. in pH 6.8 buffer solution, over 2 hours in water and pH 1.2 buffer solution. 5) Anti-inflammatory effect of clonixin argininate was increased more than that of clonixin over 6 hours, and that of clonixin lysinate was followed by lapse of time. 6) Analgesic effect of clonixin argininate was increased by 1.5 times more than that of clonixin and the effect of clonixin argininate was nearly identical with that of clonixin lysinate. 7) The absorption rates (Ka) of clonixin, clonixin lysinate and clonixin argininate were $0.169\;hr^{-1},\;0.652\;hr^{-1}$ and $0.723\;hr^{-1}$ in situ, respectively.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.3
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• pp.356-362
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• 1999

Humans may lose considerable amounts of water and electrolytes from sweat during exercise in a hot climate. Optimal ingestion of fluid-replacement beverages may overcome an obstacle factor of exercise performance in the heat. This study was performed the comparison of heart rate and blood lactate between ingestion of Prunus mume solution and water solution during graded maximal exercise using bicycle ergometer in the heat(ambient temperature of 31-32$^{\circ}C$ and relative humidity of 50-55%). Ten healthy no-heat-acclimatized males participated in the study. Exercise duration until all-out of graded testing in the condition of Prunus mume solution ingestion(786.15$\pm$47.66s) was significantly higher(P＜0.05) than the condition of water ingestion. Heart rate at 4 min during graded testing and recovery phase in the condition of Prunus mume solution ingestion was significantly lower(P＜0.05) than the condition of water ingestion. Blood lactate concentration at 30min of recovery phase after graded maximal exercise in the condition of Prunus mume solution ingestion was significantly lower(P＜0.05) than the condition of water ingestion. Recovery rate of blood lactate concentration at 15 min and 30 min of recovery phase after grated maximal exercise in the condition of Prunus mume solution ingestion was significantly lower(P＜0.05) than the condition of water ingestion. Present results suggested that ingestion of Prunus mume solution showed the positive effects on the cardiorespiratory function and acid-base regulation as compared with ingestion of water during graded maximal exercise and recovery phase in hot environment.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.5-10
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• 2009

Urea-SCR system, the selective catalytic reduction using urea as reducing agent, is a powerful technique to reduce nitrogen oxides(NOx) emitted from diesel engines. However, a tank of urea(32.5 wt%)-water solution can be frozen in low ambient temperature levels of below $-11^{\circ}C$. The purpose of this study is to understand freezing and melting phenomena of the urea-water solution, and its can be applied to get the urea-water solution from frozen it within 5 minutes after cold start. Factors considered were the type of heater and the urea tank shape. From the results, it was found that melting volume of cartridge heater B during 5 minutes of heating period was 83ml when supplying electric power of 150W. Horizontal heater B, which was put in the narrow bottom space of the tank T1, had fast melting characteristics.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.123-132
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• 2002

The literature often mentions the hardness of water in dampening solutions as possible source of problem. In most literature describes that the water hardness affects print quality. However water hardness affects not only print quality, but also emulsification of ink and dampening solution. Therefore the purpose of this study was to determine if water hardness actually affects the emulsification rate of dampening solution and ink. And this study for the factors determining the emulsion velocity, we have measured water pick-up and calculated emulsion velocity constant 'k' and activation energy.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.11
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• pp.436-439
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• 1985

An effect of the salt solution on the Water Tree Propagation was shown systematically from the actions of the salt concentration in deionized water. It may be able to suggest that the tree propagation is possibly to be connected with an intervention of the electrochemical or chemical actions of the salt solution on water tree propagation, which may likely depend on the growth level of the trees. We have pointed out that it is necessary to study the structure of water tree under the electrical stress.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.57-62
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• 2004

In the current study the effects on pump performances of a conventional centrifugal pump for Newtonian and non-Newtonian fluid were experimentally studied. The study aimed to compare the pump characteristics for Newtonian and non-Newtonian fluid. The working fluids are water, aqueous sugar solution, glycerin solution, muddy solution and pulp solution. The pump characteristics with high viscosity fluids were different. The operating efficiency for the sugar and glycerin solutions were decreased to $8.1\%$ and $12.9\%$ than that of water. The head reductions of the muddy solution for different concentration ratios were decreased to $7.97\%,\;15.11\%$ and $24.87\%$ than that of water And the head reductions of the pulp solution for different concentration ratios were decreased to $11.87\%,\;19.79\%$ md $36.81\%$ than that of water.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.173-176
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• 1999

The production of fine metal oxide particles in supercritical water has been studied. Cobalt nitrate solution and manganese nitrate solution have been selected as model solutions for metal salt aqueous solution and the particles of cobalt oxide and manganese oxide have been produced. It was observed that the production of fine metal oxide particles in supercritical water was feasible and the dehydration rate was remarkably high in supercritical water. In spite of a short residence time (3~100 seconds), fine particles ($0.5{\sim}2{\mu}m$) have been produced. In the supercritical water process, the temperature of mixer had a significant effect on particle size and size distribution. It was observed that a change in reaction temperature resulted in the control of particle size.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.203-206
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• 2001

Finding the optimal solution in the river water quality management system is very hard with the non-linearity of the water quality model. Many suggested methods for that using the linear programming, non-linear programming and dynamic programming, are failed to give an optimal solution of sufficient accuracy and satisfaction. We studied a method to find a solution optimizing the river water quality management in the aspect of the efficiency and the cost of the waste water treatment facilities satisfying the water Quality goals. In the suggested method, we use the QUAL2E water quality model and the genetic algorithm. A brief result of the project to optimize the water quality management in the Youngsan river is presented.