• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1251-1258
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• 1999

The water level control of a steam generator in the unclear power plant is an important process. Most of the water level controllers of the actual plant are PID controllers. But they have limitations in appling for tracking the set point and getting rid of disturbances, so there are some defects to apply in the actual ground even though many research works represented the resolutions to solve it. In this paper, it is suggested that the established simple PID controller in low power has the ability to remove disturbances and trace the set-point, and then possesses the real-time self-tuning function according to the variety of moving peculiarity of a plant. This function realized by making use of fuzzy logic. PID parameters are formulated by a variable ${\alpha}$ and made it fluctuate by a fuzzy inference according to level error and level error change. This mechanism makes application of actual plant effective as well as taking advantage of improving the efficiency of water level controller by way of adding the function of self-tuning instead of replacing PID controller. The computer simulation of this scheme shows the improved performance compare to conventional PID controller.

• Journal of Ecology and Environment
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• v.31 no.4
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• pp.261-267
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• 2008

Growth and photosynthetic responses of one $C_3$ and two $C_4$ plants in the family Chenopodiaceae in three $CO_2$ concentration $([CO_2])$ conditions-low (about $243{\mu}mol\;mol^{-1}$, LC), present (about 378, PC), and high (about 465, HC)-were investigated in open top chambers. The relative growth rate (RGR) and net assimilation rate in the $C_3$ plant, Chenopodium album, increased with increasing $[CO_2]$, though the RGR was not enhanced significantly in the HC condition. The leaf area ratio and leaf weight ratio of the $C_3$ plant drastically decreased with increasing $[CO_2]$, suggesting that the $C_3$ plant invests more biomass to leaves in lower $[CO_2]$ conditions. The two $C_4$ plants, Atriplex glauca and A. lentiformis, showed relatively small changes in those growth parameters. These photosynthetic-pathway-dependent responses suggest that growth patterns of $C_3$ and $C_4$ plants have been altered by past increases in atmospheric $[CO_2]$ but that there will be relatively little further alteration in the future high-$CO_2$ world.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.3
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• pp.130-136
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• 2014

The present study is performed to set up the framework of cooling tower performance predictions. The performance of mechanical forced draft cooling tower is directly related to the state of a nuclear power plant system, such as the condenser and evaporator. The main parameters related to the state of systems are as follows : wet bulb temperature, dry bulb temperature and absolute humidity. The performance evaluation of cooling tower must be considered at the power plant design. In this study, the toolkit developed by the American Cooling Tower Industry association (CTI) has been used for the framework construction. In order to validate the framework, it is being applied to the cooling tower constructed for the U.S. Nuclear Power Plant. The test results have shown good agreements with the cold water temperature on the cooling tower performance curves provided by manufacturers.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.235-241
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• 1995

YGN 3 and 4 are the nuclear power plants having System 80 characteristics with a rated thermal output of 2815 MWth and a nominal net electrical output of 1040 MWe. YGN 3 achieved commercial operation on March 31, 1995 and YGN 4 completed Power Ascension Test (PAT) at 20%, 50%, 80% and 100% power by September 23, 1995. YGN 3 and 4 design incorporates the Reactor Power Cutback System (RPCS) which reduces plant trips caused by Loss of Load (LOL)/Turbine Trip and Loss of One Main Feedwater Pump (LOMFWP). The key design objective of the RPCS is to improve overall plant availability and performance, while minimizing challenges to the plant safety systems. The RPCS is designed to rapidly reduce reactor power by dropping preselected Control Element Assemblies (CEAs) while other NSSS control systems maintain process parameters within acceptable ranges. Extensive RPCS related tests performed during the initial startup of YGN 4 demonstrated that the RPCS can maintain the reactor on-line without opening primary or secondary safety valves and without actuating the Engineered Safety Features Actuation System (ESFAS). It is expected that use of the RPCS at YGN will increase the overall availability of the units and reduce the number of challenges to plant safety systems.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.407-412
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• 2010

The purpose of this study was to investigate removal efficiencies of contaminants in night soil treatment plant using the B3 system. The samples were collected from retaining tank and settlement tank in Yechon night soil plant. We experimented concentrations of BOD, COD, SS, TN and TP. Concentration data were processed using removal efficiencies by season and correlation analysis with pilot running parameters. Removal efficiencies of total organic carbon was over 96%, TN was 98% during summer, 80.9% during winter. In the case of TP, the highest removal efficiencies was 94.1% during fall and the lowest removal efficiencies was 82% during spring. Results of correlation analysis showed two positive correlation groups and one negative group. Positive correlations were among temperature, BOD and TN. The others were pH, BOD, COD, SS, TN and TP. Negative correlation were among MLSS, BOD, COD, SS, TN, TP.

• Mycobiology
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• v.39 no.4
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• pp.290-298
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• 2011

The ability of benzothiadiazole (BTH) and/or humic acid (HA) used as seed soaking to induce systemic resistance against a pathogenic strain of Fusarium oxysporum was examined in four soybean cultivars under greenhouse conditions. Alone and in combination the inducers were able to protect soybean plants against damping-off and wilt diseases compared with check treatment. These results were confirmed under field conditions in two different locations (Minia and New Valley governorates). The tested treatments significantly reduced damping-off and wilt diseases and increased growth parameters, except the number of branches per plant and also increased seed yield. Application of BTH (0.25 g/L) + HA (4 g/L) was the most potent in this respect. Soybean seed soaking in BTH + HA produced the highest activities of the testes of oxidative enzymes followed by BTH in the four soybean cultivars. HA treatment resulted in the lowest increases of these oxidative enzymes. Similar results were obtained with total phenol but HA increased total phenol more than did BTH in all tested cultivars.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.339-346
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• 2002

Physico-chemical properties of the activated sludges(Suyoung and Changlim treatment plant), such as SVI(sludge volume index), absorbance, specific surface area, and specific resistance using Buchener funnel test were investigated with changing anaerobic storage time. This experimental condition was found that it was possible to estimate a linear relationship between their parameters such as specific surface area specific resistance, and sludge volume index(SVI). The specific surface area and the specific resistance to filtration of the activated sludges of Suyoung and Changlim treatment plant were found as 123.6~136.6$m^2$/gDS and 41.5~44.9$m^2$/gDS(dry solid), and 1.09$\times$10$^{14}$ ~5.48$\times$10$_{14}$ m/kg and 1.05$\times$10$^{14}$ ~2.48$\times$10$^{14}$ m/kg, respectively. The results gave a good linear relationship between the specific surface area and the specific resistance, r=2.25$\times$10$^{12}$ s-8.10$\times$10$^{13}$ ($R^2$=0.8885) at Suyoung treatment plant and r=1.26$\times$10$^{13}$ s-4.75$\times$10$^{14}$ ($R^2$=0.8756) at Changlim treatment plant.

• Journal of Ocean Engineering and Technology
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• v.13 no.2 s.32
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• pp.90-98
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• 1999

Boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants are degraded by creep damage due to severe operationg conditions like high temperature and high pressure for an extended period time. Such material degradation lead to various component faliures causing serious accidents at the plant. Conventional measurement techniques such as replica method, electric resistance method, and hardness test method have such disadvantages as complex preparation and measurement procedures, too many control parameters, and therefore, low practicality and they were applied only to component surfaces with good accessibility. In this study, both artificial creep degradation test using life prediction formula and frequency analysis by ultrasonic tests for their preparing creep degraded specimens have been carried out for the purpose of nondestructive evaluation for creep damage which can occur in high-temperature pipelline of fossil power plant. As a result of ultrasonic tests for crept specimens, we confirmed that the high frequency side spectra decrease and central frequency components shift to low frequency bans, and bandwiths decrease as increasing creep damage in backwall echoes.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.256-262
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• 2007

Image processing systems have been used to measure the plant parameters such as size, shape and structure of plants. There are yet some limited applications for evaluating plant colors due to illumination conditions. This study was focused to present adaptive methods to analyze plant leaf color regardless of illumination conditions. Color patches attached on the calibration bars were selected to represent leaf colors of lettuces and to test a possibility of health monitoring of lettuces. Repeatability of assigning leaf colors to color patches was investigated by two-tailed t-test for paired comparison. It resulted that there were no differences of assignment histogram between two images of one lettuce that were acquired at different light conditions. It supported that use of the calibration bars proposed for leaf color analysis provided color constancy, which was one of the most important issues in a video color analysis. A health discrimination equation was developed to classify lettuces into one of two classes, SOUND group and POOR group, using the machine vision. The classification accuracy of the developed health discrimination equation was 80.8%, compared to farmers' decision. This study could provide a feasible method to develop a standard color chart for evaluating leaf colors of plants and plant health monitoring system using the machine vision.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.36-37
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• 2004

$\alpha$-Chloromethylnaphthalene is a valuable compound for obtaining of the plant growing stimulator - $\alpha$-napthylacetic acid. Chloromethylation of naphthalene by paraformaldehyde in the presence of glacial acetic acid, phosphoric and hydrochloric acids at temperature 80-85$^{\circ}C$ and duration - 6 hours the $\alpha$-chloromethyl-naphthalene yield was 55-57%. Using Box-Wilson method for mathematical planning of experiment carried out optimization of its synthesis for purpose increasing $\alpha$-chloromethylnaphthalene yield. Preliminary, one - factor experiments were carried out for selecting independence main parameters influencing on the synthesis. A full factor experiment of 2$^3$with extended matrix of planning was used for optimization. Aiming to increase the $\alpha$-chloromethylnaphthalene yield, the obtained mathematical model was used for program of sharp raising on the reply surface. The received optimal conditions for the $\alpha$-chloromethylnaphthalene synthesis were selected as following: molar ratio of naphthalene - parapfsormaldehyde of 1 : 2; temperature -105$^{\circ}C$; duration of the reaction -3 hours. The yield of $\alpha$-chloromethylnaphthalene under these optimal conditions was 75 %.