• Journal of Animal Science and Technology
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• v.54 no.4
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• pp.241-246
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• 2012

The goal of this study was to verify the phylogenetic status of the Korean native goats (KNG). We determined the complete sequence of the mitochondrial cytochrome b gene in 48 goats among four populations. We also analyzed genetic variability within goats, and a phylogenetic analysis was performed by comparison with other country's goats. Three nucleotide substitutions were detected, and two of these were missense mutations that occurred due to a substitution of amino acid. Four haplotypes were defined from KNG. Three of these haplotypes were only found in the Chinese goat. However, the other haplotype was KNG-specific. In the phylogenetic analysis, four clades (A~D) were classified among domestic goats, and the KNG was classified into clade 1 that estimated as lineage A based on the D-loop sequence. Each haplotype from the KNG was clustered closely with that of the Chinese goat. The results of haplotype distribution and phylogenetic location suggest that strong gene flow occurred from China to the Korean Peninsula.

• Journal of Korea Water Resources Association
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• v.57 no.4
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• pp.277-287
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• 2024

Water distribution system (WDS) is exposed to various water quality incidents during its operation. This study utilized Quantitative Microbial Risk Assessment (QMRA) to analyze the risk associated with potential virus intrusion in WDSs. Additionally, the study determined the location and operation of rechlorination facilities to minimize potential risk. In addition, water quality resilience was calculated to confirm that the chlorine concentration maintains within the target range (0.1-1.0 mg/L) during normal operation. Hydraulic analysis was performed using EPANET, while EPANET-MSX was linked to simulate the reactions between viruses and chlorine. The proposed methodology was applied to the Bellingham network in the United States, where rechlorination facilities capable of injecting chlorine concentrations ranging from 0.5 mg/L to 1.0 mg/L were considered. Results indicated that without rechlorination facilities, the Average risk was 0.0154. However, installing rechlorination facilities and injecting chlorine at a concentration of 1.0 mg/L could reduce the Average risk to 39.1%. It was observed that excessive chlorine injection through rechlorination facilities reduced water quality resilience. Consequently, a rechlorination facility with a concentration of 0.5 mg/L was selected, resulting in a reduction of approximately 20% in average risk. This study provides insights for designing rechlorination facilities to enhance preparedness against potential virus ingress in the future.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.7
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• pp.481-484
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• 2011

Although formation of organic chloramines have been studied for decades, most of them have involved model organic compounds (e.g., amino acids) but not naturally occurring organic nitrogen in water. This study investigated formation of organic chloramines during chlorination of 16 natural organic matters (NOM) solutions which were isolated from surface water and contained dissolved organic nitrogen (DON). Organic chloramine yields per chlorine consumption was $0.25mg-Cl_2/mg-Cl_2$. Upon chlorination of NOM solutions, organic chloramines were rapidly formed within 10 minutes. The average organic chloramine yields upon addition of chlorine in to NOM solutions were $0.78mg-Cl_2/mg-DON$ at 10 minutes and $0.16mg-Cl_2/mg-DON$ at 24 hours. Organic chloramine yields increased as the dissolved organic carbon/dissolved organic nitrogen (DOC/DON) ratios decreased. Chlorination of molecular weight (10,000 Da) fractionated samples showed that the influence of DON molecular weights on the organic chloramine formation was minimal.

• Polymer(Korea)
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• v.37 no.5
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• pp.553-556
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• 2013

Chlorine dioxide gas has an excellent ability for sterilization and deodorization, and is harmless to humans. However, it is very unstable and explosive as it is highly concentrated, thus its use in the air clean fields has been limited. Therefore, there is need to control chlorine dioxide gas at a low concentration for a long time. Chlorine dioxide gas could be produced slowly and sustainedly since the release of acetic acid from the polymer hydrogels delayed the reaction between acetic acid and sodium chlorite. In addition, as the amount of both acetic acid sodium chlorite loaded within the hydrogel and on the membrane increased, respectively, the generation amount of chlorine dioxide gas increased. The result shows that the use of polymer hydrogels has the potential to control the generation of chlorine dioxide gas.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.707-711
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• 2007

낙동강과 밀양강의 합류지점에 위치한 김해시 딴섬 지역의 지표면하 $25{\sim}35\;m$ 구간에 형성되어 있는 고투수성 충적층 내 염소이온의 수리분산특성을 연구하기 위한 수렴흐름 추적자시험(convergent flow tracer test)이 수행되었다. 추적자로는 IW-1공과 IW-2공에서 각각 염소이온 5kg이 순간주입(instantaneous injection) 되었으며, PW공에서 일정한 양수율(2,500 m3 /day)로 채수하면서 염소이온농도를 관측하였다. 염소이온 주입 후 경과시간에 따른 염소이온농도 자료를 이용하여 농도이력곡선과 누적질량회수곡선이 산출되었으며, 관측된 염소이온농도의 정규분포를 검증하기 위한 일반통계분석이 수행되었다. 그리고, 농도이력의 증가/감소 구간에서의 함수를 추정하였으며, 두 시험에서 동일한 시간에 관측된 염소이온농도의 상관성이 분석되었다. 본 현장에서 수행된 추적자시험에 의한 종분산지수의 추정은 CATTI 코드(Sauty and Kinzelbach, 1992)에 의해 해석되었다. 추정된 종분산지수는 IW-1공과 PW공 구간에서는 0.4152 m, IW-2공과 PW공 구간에서는 0.4158 m 로서 매우 유사한 값으로 나타났다. 이는 추적자시험이 수행된 충적층에서의 용질이송이 방사상으로 비교적 균일함을 의미하는 것이다. 본 연구에서 수행된 추적자시험의 규모(2 m)를 Xu and Eckstein(1995)이 제시한 방정식에 대입하여 산정된 종분산지수는 0.0458 m 이었다. 이러한 결과는, 본 연구지역에서 수렴흐름 추적자시험에 의해 추정된 고투수성 충적층의 종분산지수가 일반적인 자연대수층에 비해 9.1배 정도 높다는 것을 의미한다. 이는 시험대수층의 투수성이 매우 높아 염소이온의 용질이송이 매우 빠르게 발생되었기 때문이다. 본 연구에서 추정된 종분산지수를 Gelhar et al.(1992)의 연구 결과와 비교 분석한 결과에서도 시험규모에 비해 매우 높은 수리분산이 발생된 것으로 나타났다. 그리고 염소이온의 확산면적을 추정하기 위해, 수렴흐름 추적자시험에 의한 종분산지수와 시험대수층의 평균선형유속을 이용하여 종분산계수를 구하였다. 현장에서 수행된 양수시험에 의한 평균선형유속 22.44 m/day와 평균 종분산지수 0.4155 m를 적용하여 산정된 종분산계수는 $9.32\;m^2/day$이었다. 따라서, 시험부지 내 충적층에서 일정한 양수율$(2,500\;m^3/day)$로 지하수를 개발할 시에 양수정 주변지역으로 유입되는 염소이온의 확산면적은 1일 $9.32\;m^2$ 정도일 것으로 나타났다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.133-142
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• 2008

This paper studies the early-aged chloride binding capacity of various blended concretes including OPC(ordinary Portland cement), PFA(pulversied fly ash), GGBFS(ground granulated blast furnace slag) and SF(silica fume) cement paste. Cement pastes with 0.4 of a free water/binder ratio were cast with chloride admixed in mixing water, which ranged from 0.1 to 3.0% by weight of cement and different replacement ratios for the PFA, GGBFS and SF were used. The content of chloride in each paste was measured using water extraction method after 7 days curing. It was found that the chloride binding capacity strongly depends on binder type, replacement ratio and total chloride content. An increase in total chloride results in a decrease in the chloride binding, because of the restriction of the binding capacity of cement matrix. For the pastes containing maximum level of PFA(30%) and GGBFS(60%) replacement in this study, the chloride binding capacity was lower than those of OPC paste, and an increase in SF resulted in decreased chloride binding, which are ascribed to a latent hydration of pozzolanic materials and a fall in the pH of the pore solution, respectively. The chloride binding capacity at 7 days shows that the order of the resistance to chloride-induced corrosion is 30%PFA > 10%SF > 60%GGBFS > OPC, when chlorides are internally intruded in concrete. In addition, it is found that the binding behaviour of all binders are well described by both the Langmuir and Freundlich isotherms.

• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.115-121
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• 2001

Biological Treatment of Wastewater Containing Chlorinated Phenols by a Mixed Culture. Lee, Wan-Seok1, Sang-Wook Jung, Chan-Sun Park, Byung-Dae Yoon, Jang-Eok Kim\ and Hee-Mock Oh*. Environmental Bioresources Laboratory, Korea Research Institute of Biosicence and Biotechnology, Taejon, Korea, 1 Department of Agricultural Chemistry, Kyungpool< National University, Taegu, Korea - The biodegradation of chlorinated phenols in an artificial wastewater was investigated using a mixed culture. The mixed culture was composed of 8 microorganisms isolated from the soil contaminated with various chlorinated phenols. Pseudomonas sp. BM as a main constituent of a mixed culture was Gram-negative, catalase- and oxidase-positive, and rod-shaped, and did not grow at 41°C. It degraded 99% of initial 500 mg!1 of pentachlorophenol (PCP) in the minimal salts medium as a sole source of carbon and energy within 3 days. The degradation efficiency of Pseu.domon.as sp. BM was not affected by the other organic carbon and nitrogen compounds. Pseudomonas sp. BM was able to grow in a broad range of pH 5 - 8, and degrade 2,000 mg/1 PCP. In the experiment with an artificial wastewater containing chlorinated phenols, the degradation efficiency of the mixed culture was the range of 73% (2,4-dichlorophenol) -96% (2-chlorophenol) during an incubation of 7 days. In a continuous culture experiment, the degradation efficiency of mixed culture plus activated sludge was about 2 times higher than that of the control containing only activated sludge. These results indicate that it is possible to apply the mixed culture to other wastewaters containing chlorinated phenols. Key words: Biodegradation, chlorinated phenols, pentachlorophenol, Pseudomonas sp. BM

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.753-759
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• 2006

To predict service life of concrete structures exposed to chloride attack, surface chloride concentration, diffusion coefficient of chloride ion, and chloride corrosion threshold value in concrete, are used as important factors. Of these, as the diffusion coefficient of chloride ion for concrete is strongly influenced by concrete quality and environmental conditions of structures and may significantly change the service life of structures, it is considered as the most important factor for service life prediction. The qualitative factors affecting the penetration and diffusion of chloride ion into concrete are water-cement (W/C) ratio, age, curing conditions, chloride ion concentration of given environment, wet and dry conditions, etc. In this paper the influence of W/C ratio and curing conditions on the diffusion characteristics of chloride ion in concrete was investigated through the chloride ion diffusion test. In the test, the voltages passing through the diffusion cell were measured by accelerated test method using potential difference, and then with the consideration of IR drop ratio the diffusion coefficient of chloride ion for concrete with different W/C ratios were estimated by Andrade's model. Furthermore, under different curing conditions formulas for the estimation of the diffusion coefficient of chloride ion have been proposed by the regression analysis considering the effect of W/C ratio and age.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.413-417
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• 2002

Gitelman's syndrome is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria that has recently been reported to be linked to thiazide- sensitive Na-Cl cotransporter gene mutation. In this study, we performed renal clearance studies to differentiate Gitelman's from Bartter's syndrome and to confirm the diagnosis in two patients clinically diagnosed with Gitelman's syndrome. Each patient was hydrated by 20 mL/kg body weight of oral water within 30 minutes, which was followed by intravenous half saline. When urinary flow reached 10 mL/min, samples of urine and serum were obtained to calculate the osmolar clearance, free water clearance, chloride clearance, and distal fractional chloride reabsorption. Subsequently, furosemide or hydrochlorothiazide was administered. Samples were collected and the same parameters were calculated. In our patients, chloride clearance was increased more than 10 times after furosemide administration(2.1 : 25.7 and 2.2 : 27.4 mL/min/100 mL GFR), but not increased after hydrochlorothiazide treatment(2.1 : 1.6 and 2.2 : 2.6 mL/min/100 mL GFR). And the distal fractional chloride reabsorption was significantly decreased by furosemide injection (73% : 15% and 75% : 4.6%), whereas hydrochlorothiazide had no effect on it(73% : 63% and 75% : 78%). These findings indicate that our patients have a defect in thiazide-sensitive Na-Cl cotransporter in the distal tubule, which is compatible with the pathophysiology of Gitelman's syndrome.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.14 no.2
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• pp.129-132
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• 2003

Chlorine gas is highly irritating gas that, when inhaled, can damage larger airways as well as distal lung structure. It occurs usually result in mild ocular, oropharyngeal, or respiratory symptom and recovery may proceed slow for several weeks. We reported four cases of dysphonia due to acute chlorine inhalation during a swimming pool accident were treated by voice therapy and medication.