• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.611-619
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• 2013

In this study, Back Tracing Calculation Method was developed to determine the leakage location and leakage amount. Previously developed determination method of monitoring location and newly developed Back Tracing Calculation Method were applied to the sample pipe network and real size pilot plant. After leakage was assumed in the pilot plant, leakage location and leakage amount could be traced by Back Tracing Calculation Method. From the results, it was found that Back Tracing Calculation Method can be applied for the leakage detection in water distribution system. Furthermore, this method can be applied for the pressure management or leakage detection as a pressure control method in water distribution system.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.3
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• pp.56-60
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• 1999

In this study the feasibility of usage of raw sludge (sludge from water treatment plant) and chalk from schools and institutes was investigated to remove the phosphorus in water and wastewater. In this study phosphorus removal efficiencies of sludge and chalk were investigated by changing various factors. The time to reach the equilibrium using chalk and raw sludge under different pHs was obtained. Based on this result, Freudlich adsorption isotherm was applied. Results showed that a portion of phosphorus was removed by adsorption to chalk and raw sludge. The phosphorus removal efficiency using calcinated chalk was about three times higher than that of chalk. It means that some portion of $CaCO_3$ contained in chalk was converted to CaO by calcination and this was proved by X-ray diffraction experiment. About 90% phosphorus removal was observed using sludge and calcinated chalk respectively while about 20% phosphorus removal efficiency was achieved using chalk from the water sample in Lake Sihwa.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.86.6-86
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• 2001

For discriminating between water and oil, a novel method is proposed in this paper. As a fundamental result, the temperature dependence of ultrasonic travel time of water and oil measured from 5$^{\circ}C$ to 40$^{\circ}C$ at a step of 5$^{\circ}C$ is found as that the ultrasonic travel time of oil increases with increasing temperature, whereas that of water decreases. The proposed method for discriminating between water and oil is based on the opposite temperature dependence of ultrasonic travel time of water and oil. Besides the advantages of non-invasion and on-line measurement, there are no requirements of measuring the temperature of liquid being detected and obtaining previously a large quantity of database, and furthermore, only two times of measurements are ...

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.469-473
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• 2003

This study was conducted to determine the effect of a mixture of two water-soluble dietary fibers, psyllium husk and glucomannan, on serum lipids, fecal fat excretion and body fat. Twenty one female Sprague-Dawley rats were randomly assigned into three groups (control, pair-fed control and test group) and fed a high saturated fat (20% lard) diet (control diet) or a test diet (psyllium husk and glucomannan added to the control diet at the level of 0.9% and 0.68%, respectively) for 8 weeks. Pair-fed control rats were allowed to eat the amount of diet consumed by test group the preceding day. The body weight gain and food efficiency ratio of test group were significantly lower compared with these of control group. The mean values of body weight gain and food efficiency ratio were lower in test group than in pair-fed control group, but the difference was not significant. There were no differences in food intake. The dry weight and water content of feces and fecal fat excretion were markedly greater in test group than in control groups. Serum total cholesterol and triacylglycerol levels were significantly lower in test group than in two control groups.1'he rats of two control groups had higher body fat contents than that of test group. These results indicate that the combination of the two water-soluble dietary fibers, psyllium husk and glucomannan, can be used as a potent lipid-lowering agent in individuals consuming high saturated fat diet.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.223-224
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• 2008

초초임계압 화력발전 제어계통 설계와 관련하여 보일러 제어시스템의 기본 요건인 제어전략을 구현하기 위해 현재 표준화력 500MW 제어시스템과 제어로직을 기반으로 1000MW급에서 필요로 하는 새로운 구조의 제어에 요구되는 제어전략에 대해 각종 제어 운전 모드의 구성과 각 운전 모드에서의 제어전략을 개발하고 있다. 최신제어시스템에서 중요하게 취급되는 자동 플랜트 제어(Automatic Plant Control, APE)의 각종 제어전략 구성에 중점을 두고 있으며 Unit Master Control, Boiler Master Control, Turbine blaster Control, Throttle Pressure Control, Fuel/Air Master Control, Forced Draft Fan Control, Induced Draft Fan Control, Primary Air Fan, Feed Water Master Control, Super Heater/Reheater Steam Temp Control 등의 제어전략을 논하고, 실제 프로세스 응단특성 파악을 위해 국내 신규발전소를 방문하여 수집한 프로세스 응답시험 결과와 특성을 분석하고 USC에 적용하기위한 보일러 제어전략에 대해 논하고자 한다.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.399-404
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• 2008

Condensing gas boiler units may make a big role for the reduction of energy consumption in heating industries. In order to decrease the energy consumption of a condensing gas boiler unit, the effective control of the system is necessary. In this study, control algorithms of a condensing gas boiler were developed. Control algorithms are composed of the setpoint algorithm and the control algorithm. The setpoint algorithm consists of the supply water temperature setpoint algorithm and the pump setpoint algorithm. The control algorithm consists of the gas valve control algorithm and the blower control algorithm. In order to analyse the performance of control algorithms, dynamic models of a condensing gas boiler system were used. Simulation results showed that control algorithms developed for this study may be practically applied to the condensing gas boiler.

• Journal of Environmental Health Sciences
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• v.43 no.6
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• pp.499-508
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• 2017

Objective: This study was conducted to investigate changes in microbiological quality according to various storage conditions in the drinking process of bottled mineral water. Methods: Heterotrophic plate counts ($21^{\circ}C$ and $36^{\circ}C$) and pathogenic indicators (total coliforms, fecal Streptococcus, Pseudomonas aeruginosa, Clostridium perfringens, Salmonella, and Shigella) were analyzed in commercial bottled mineral water stored under different conditions ($4^{\circ}C$, $20-25^{\circ}C$, $36^{\circ}C$) after injecting saliva. The heterotrophic plate counts were analyzed twice per day for the first week and once per day for the three weeks after. Pathogenic indicators were analyzed at the beginning and end (initial and final). Results: The results of the microbiological quality of the bottled mineral water in contact with saliva showed that heterotrophic plate counts ($21^{\circ}C$) had a tendency to be sustained or decrease slightly after 10 days. Heterotrophic plate counts ($36^{\circ}C$) had a high population in the initial samples and gradually decreased at $4^{\circ}C$ storage, but it remained constantly high in storage at $20-25^{\circ}C$ and $36^{\circ}C$. In the general drinking condition, the population was slightly higher than the control, but the overall trend was similar. Conclusions: As a result of the microbiological quality of mineral bottled water in contact with saliva during the process of drinking, heterotrophic plate counts ($21^{\circ}C$ and $36^{\circ}C$) showed a high population compared to the control, which was only opened and not in contact with saliva. In some samples, pathogenic indicators were also detected. Therefore, it is desirable to consume bottled mineral water as soon as possible after opening.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.839-844
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• 2000

In developing of soil wetting agents using the mixture of polyoxyethylene octylphenyl ether [$C_8H_{17}O$ $(C_2H_4O)_{10}H$, POE] and polyoxyethylene+polypropyleneoxide tridecylether (1:1, w/w, CM-1), the effect of base carriers such as zeolite and vermiculite on changes of concentration of POE and on initial wetting of peat-vermiculite media were determined. The concentration of POE in the treatment of zeolite was higher than that of vermiculite. The treatments of POE+CM-1 with zeolite or vermiculite as carrier were effective in initial water retention of root media having about 510 mL of water per pot, where those of AquaGro and control had 490 mL and 400 mL of water per pot, respectively. In the evaporative water loss, the treatment of zeolite and AquaGro were faster than those of control and vermiculite. The treatment of AquaGro had faster water movement in root media than those of POE+CM-1 regardless of carriers and same trends were observed in the volume of water infiltrating into root media. Also, increasing the amount of POE+CM-1 resulted in increased water retention capacity, evaporative water loss, water movement in root media and amount of water infiltrating into root media.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.5
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• pp.227-234
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• 2018

The smart irrigation system using ICT technology is crucial for stable production of upland crops. The objective of this study was to develop a smart irrigation system that can control soil water, depending on irrigation methods, in order to improve crop production. In surface irrigation, three irrigation methods (sprinkler irrigation (SI), surface drip irrigation (SDI), and fountain irrigation (FI)) were installed on a crop field. The soil water contents were measured at 10, 20, 30, and 40 cm depth, and an automatic irrigation system controls a valve to maintain the soil water content at 10 cm to be 30%. In subsurface drip irrigation (SSDI), the drip lines were installed at a depth of 20 cm. Controlled drainage system (CDS) was managed with two ground water level (30 cm and 60 cm). The seasonal irrigation amounts were 96.4 ton/10a (SDI), 119.5 ton/10a (FI), and 113 ton/10a (SI), respectively. Since SDI system supplied water near the root zone of plants, the water was saved by 23.9% and 17.3%, compared with FI and SI, respectively. In SSDI, the mean soil water content was 38.8%, which was 10.8% higher than the value at the control treatment. In CDS, the water contents were greatly affected by the ground water level; the water contents at the surface zone with 30 cm ground water level was 9.4% higher than the values with 60 cm ground water level. In conclusion, this smart irrigation system can reduce production costs of upland crops.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.4
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• pp.137-147
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• 2011

This study aims to find out the construction process and planning characteristics of Suwon and Hwa-sung in 18th century from the point of water system. This study has an explanatory approach. The planning intents in the water system was driven out by analyzing various planning elements in relation to water system in the process of constructing Hwa-sung in 18th century. Using Entire Map of Hwa-sung, land registration map made in 1911 and topographic map of 1/10,000 scale made in 1917, water system and interpretation of spatial structure in Hwa-sung were analyzed. The results are as follows(Planning characteristics of the water system in Haw-sung in 18th century are as follows). Firstly, in determining the spatial structure and location of Hwa-sung, water system had an important role. Secondly, integrated drainage system was planned by the organization of natural and artificial water stream. Thirdly, the main street system and land use structure were planned in relation with water system. Fourthly, territoriality of main area was planned with water stream. Fifthly, ponds were constructed for flood control and they had important role as landscape elements. Sixthly, water stream was used as intentional BiBo element. As a result of the study, the weater system of Hwa-sung in 18th century was planned by the organization of natural and artificial water stream in relation with the location of new town and wide area's spatial structure, street system, land use structure, territoriality of main area, terriflood control, water quality protection, landscape, 비보 and urban daily life.