• Proceedings of the KSME Conference
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• 2003.04a
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• pp.84-89
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• 2003

Water leak is one of topics with great concern in Korea and many other countries, because of decreasing water supplies and the deterioration of old pipeworks. Correlation techniques have been widely used in leak detection of water pipes, which allow to locate a leak point based on the correlation of leak noise at two sites along water pipes. In this study, both the cross-correlation method and the conventional arrival time difference method are applied in order to analyze and to locate a leak point of a water pipe. In experiment, a 150 m of whole length waterwork pipeline system was constructed in a ground, and several types of leak noise were installed on the pipeline in order to control leak condition. Both the cross-correlation technique and the arrival time difference method showed favorable results at leak detection with the experimental pipeline system.

• Journal of Environmental Science International
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• v.7 no.5
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• pp.591-598
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• 1998

This study was conducted to evaluate water quality in the Keum River estuary using principal component analysis. The results was summarized as follow; Water quality in the Keum River estuary could be explained up to 70.40% by three factors which were included in the inffluent loading by the Keum River and Kyungpo cheon(38.99%), seasonal variation and organic matter pollution(19.05%), sediment resuspension and internal metabolism(12.35%). For spatial variation of factor score, artificial pollutant loading is highest at st.1, below Keum River barrage, and decreases toward the outer sea. For annual variation of factor score, factor 1 was highly related to artificial pollutant leading, and it was gently increased in 1994. Also, organic matter pollution, sediment resuspension and internal metabolism were increased to every year. It is necessary to control the nutrient leading by Keum river and Kyongpo cheon for Water quality management of estuary.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.356-363
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• 1997

Many research works have been carried out to investigate the factors governing the performance of diesel engine. The area of the study has been focused on reducing both of NOx and smoke because of many difficulties to reduce them simultaneously in diesel engines. One of the efforts is an application of EGR technology to reduce NOx emission, which is very effective, but increases other emissions and makes fuel economy worse. In order to solve the problem, EGR is employed with water emulsified fuel and tested in this paper. Emulsified fuel is produced by centrifugal mixer and the amount of water is controlled by water injector and pulse generator, and EGR rate is controlled with 6-step control valve. The chamber pressure, fuel consumption and emissions are measured with various values of both EGR and water mixing rate, The results show that NOx emission is reduced much rather and smoke is also reduced simultaneously.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.153-160
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• 2011

Ozone process is currently applied in 24 water treatment plants in Korea to control micropollutants and taste & odor compounds. However, one of the chlorine resistant protozoa, cryptosporidium, is not being considered as ozone disinfection performance whereas U.S. is already regulate Cryptosporidium by ozone disinfection. two ozone plants(PH, UH WTP) operation conditions are investigated for disinfection performance comparing Korea disinfection regulation and U.S. regulation. The ozone plants are unable to get Cryptosporidium inactivation credits by Korea disinfection regulation. However, the inactivation credit for Cryptosporidum was increased when the U.S. disinfection regulation was applied. The Korea disinfection credit regulation need revision to practical aspects.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.06a
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• pp.177-189
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• 1996

Raverase osmosis or ultrafiltration systems have generally been regarded as hard to validate about WFI production. Though the Japanese and US Pharmacopoeias have allowed distillation and RO to be applied to WFI production process, only water stills, especially multiple effects have practically been employed for parenteral water production. On the other hand, the latest analysis has shown that even distillate contains such volatile organic matters as trihalomethanes and traces of heavy metals at a little higher concentration than supposed. The JP requires TOC to be monitored in WFI process based on RO or UF systems to control the concentration below 300ppb, but very few monographs or papers have so far been published about the concentrations of organic volatile matters in distillate. (See table 1-1) Therefore, this paper proposes a new applicable WFI systems based on the result of purified water analysis with some membranes used in the process. A well combined membrane system with other units could be expected to provide less amount of impurities in membrane-treated water than in distillate.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1155-1160
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• 2009

Poly(lactide) (PLA)-coated paperboards were prepared by solution coating and thermo-compression coating methods and their effect of coating on the packaging properties such as tensile, water resistance, water vapor barrier, and heat sealing properties was tested. Compared with uncoated control paperboard, tensile strength (TS) of PLA-coated paperboard increased profoundly (2.2-2.6 folds) with slight increase in elongation at break (E). Water absorptiveness (WA) of the paperboard decreased 74-170 folds and water vapor permeability (WVP) decreased 6.3-22.1 folds by coating with PLA, which indicates an increase in the hydrophobicity of the surface of paperboard. Compared with polyethylene (PE)-coated paperboard, both PLA-coated paperboard exhibited 2.3 time higher heat sealing strength. In addition, the PLA-coated paperboards showed equal or higher wet TS than PE-coated paperboard. All the test results showed that the paperboard coated by the thermo-compression coating method was similar to or better than those of coated by the solution coating method.

• The Journal of Korean Medicine
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• v.21 no.1
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• pp.91-98
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• 2000

The water extract of Seongpungtang(SPT) has commonly been used for treatment of ischemic brain damage in Oriental traditional medicine. However, little is known about the mechanism by which the water extract of SPT rescues brain cells from ischemic damage. To elucidate the protective mechanism of ischemic induced cytotoxicity, the regulation of Lipopolysaccharide (LPS) and PMA (phobol-12-myristate-13-acetate) induced iNOS expression in microglial cells was investigated. LPS and PMA treatment for 48 hr in microglial cells markedly induced nitric oxide (NO), but treatment of the cells with the water extract of SPT decreased nitrite formation. In addition, LPS and PMA treatment for 48 hr induced severe cell death in microglial cells. However treatment of the cells with the water extract of SPT did not induce significant changes compared to the control cells. Furthermore, NO production was markedly decreased by treatment of nuclear factor kappa B(NF-kB) inhibitor, pyrrolidine dithiocarbamate(PDTC). According to the above results, it is suggested that the protective effects of the water extract of SPT against ischemic brain damage may be mediated by regulation of iNOS during ischemic condition.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.576-582
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• 2015

In recently, the Korea government is concerning on non-point source pollution management to improve water quality. The objective of this paper is to investigate the improvement measurement for management of livestock wastes. As a result, we find that the National Pollution Source Survey is necessary to establish the unified database system with the Korea Statistics(KOSAT) in order to minimize the difference between relevant data. The investigation for environmental impact of livestock manure should be supported the designation of control areas and establishment of the technical guidelines including target material, monitoring site, standard method, etc. In addition, it should be followed by appropriate nutrient recycling and proper fertilizer usage based on social consultation and cost-benefit analysis.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.105-110
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• 1999

Unused irrigation water due to delievery losses and management losses. and ground water releases from infiltration in the paddy irrigation system are eventually returned to the stream. They are called as irrigation return flow. It affects the discharge of drought flow in the down strenamflow. And it may contain chemicals, and threaten streamflow quality . Thus, the accurage estimation of irrigation return flow is important to the streamflow modeling and water resources planning , and also to the control of agriculutral nonpoint source pollution . The irrigation return flow of pumped water was investigated in the Keum river watershed.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.883-887
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• 1998

Hydration is the main reason for the growth of the material properties. A exact parameter to control the chemical and physical process is not the time, but the degree of hydration. Therefore, it is reasonable that development all material properties should be formulated in terms of degree of hydration. Mathematical formulation of degree of hydration is based on combination of reaction rate functions. The effect of moisture conditions as well as temperature on the rate of reaction is considered in the degree of hydration model. This effect is subdivided into two contributions: water shortage and water distribution. The former is associated with the effect of on the progress of hydration. The water needed for progress of hydration do not exist and there is not enough space for the reaction products to form. The latter is associated with the effect of free capillary water distribution in the pore system. Physically absorption layer does not contribute to progress of hydration and only free water is available for further hydration.