• Korean Journal of Food Science and Technology
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• v.24 no.2
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• pp.132-136
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• 1992

The effects of chlorine treatment on the lipid composition of wheat flour were studied by treating flour with different amounts (1, 2 and 4 ounces per 100 pounds of flour) of liquidized chlorine gas. The contents of free lipid increased slightly while those of the bound lipid decreased at all levels of chlorine used. The contents of neutral lipid in the free lipid decreased while those in the bound lipid increased as the level of chlorine increased. The contents of triglycerides in the free and bound lipids decreased as the level of chlorine increased. As the level of chlorine increased, digalactosyl diglycerides in the bound lipid decreased, whereas those in the free lipid increased within the range of 1 to 2 oz of chlorine. The phosphatidylcholine content in the free and bound lipids decreased while the lysophosphatidylcholine increased in both free and bound lipids as the level of chlorine increased. The content of saturated fatty acids increased while that of unsaturated ones decreased as the level of chlorine increased.

• Journal of the Korean Electrochemical Society
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• v.15 no.4
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• pp.242-248
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• 2012

The measurement of residual chlorine as a disinfectant is very important to ensure the safety against the pathogenic microbes and to suppress injection. The portable free chlorine sensor was fabricated with a disposable strip format by a screen printing method. The strip sensors prepared with a carbon-Ag/AgCl(cathode-anode) combination exhibited less interfering responses towards combined chlorine species(especially $NHCl_2$) and oxygen than the sensors prepared with other metals(i.e., gold and platinum). Free chlorine was determined chronoamperometrically with carbon-based electrodes at an applied potential of -0.3 V(vs. Ag/AgCl). A channel was built on the strip-type electrode for easy sampling, and the resulting strip sensors were employed to determine the concentrations of residual free chlorine.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.627-634
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• 2009

This study was done to find out the formation mechanism of chlorate by electrochemical process using chloride ion ($Cl^-$) as an electrolyte. Firstly, the effective factors such as pH and initial chloride concentration were figured out to see the formation property of chlorate during electrolysis. And the relation of free chlorine, and mixed oxidants such as OH radical and ozone with chlorate were estimated to concretize the formation mechanism. As a result, it was found that the major reaction of chlorate formation would be electrochemical reaction with free chlorine, and also the direct oxidation of chloride ion and the reaction by OH radical were participated in the formation of chlorate. Moreover, it was observed that formed chlorate was oxidized to perchlorate. Lastly, the optimum condition was recommended by comparing free chlorine with chlorate concentration during the electrochemical process with the different electrode separation.

• Clean Technology
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• v.21 no.1
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• pp.45-52
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• 2015

We have introduced switching poles in the conventional electrolysis for the removal of ammonia in aquaculture wastewater to prevent the fouling on the electrode surface by the deposition of insoluble metallic compounds. We have also tried to locate the optimal period of switching poles considering the effect of the current loss during switching poles on the free chlorine generation. First, we have observed the decrease of free chlorine generation with the decrease of the period of switching poles due to the expected current loss, and this would lead to the decrease of ammonia removal efficiency. Meanwhile, the measurement of calcium and magnesium concentration in wastewater vs. the period of switching poles have demonstrated that a properly low level of fouling on the electrode surface could be retained with a period of switching poles of less than 60 sec by the decomposition of metallic compounds during switching poles. In a summary, we have optimized the period of switching poles to gain a high level of free chlorine generation and a high level of fouling prevention on the electrode at the same time.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.248-248
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• 2011

유전체 모세관을 이용한 해수에서의 펄스고전압 방전 특성을 연구하였다. 내경 1, 2, 3 mm의 구멍이 뚫린 Quartz 블럭에 외경 1, 2, 3 mm의 SUS 핀을 삽입하였고 삽입된 핀의 끝이 해수에 담구어 지도록 하여 고전압 방전을 발생 시켰다. 인가된 펄스 고전압은 5 kHz의 반복 주파수를 가지며, Pulse 폭을 $1{\sim}2.5{\mu}sec$까지 변화 시켜 전압전류 파형과 방전양상을 살펴 보았다. 방전은 펄스폭 변화에 따라 전해전도 전류에 의한 모세관 가열, 모세관내 미세기포형성, 기포내의 코로나 방전 개시 그리고 글로우 또는 아크방전으로 발전하는 것을 확인하였다. 모세관의 길이는 각각의 구경에 대하여 5 mm, 10 mm 두 가지로 변화하여 실험하였고, 모세관 길이 10 mm 조건에서는 방전이 매우 불안정 하였다. 각각의 방전조건별로 1~5분간 방전을 진행하여 해수내의 유리염소의 농도 변화를 살펴본 결과 방전모드가 글로우 또는 아크 방전 모드에서 단위 에너지당 유리염소 발생 수율이 큰 폭으로 증가하는 것을 확인할 수 있었다.

• Journal of Life Science
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• v.30 no.2
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• pp.178-185
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• 2020

Rice bakanae is a typical seed-borne and seed-transmitted disease caused by infection by Fusarium fujikuroi. Seed disinfection using chemical fungicides (such as benomyl and prochloraz) is most effective in controlling the disease, but the emergence of fungicide-resistant strains has recently been increasing. Slightly acidic hypochlorous acid water (SAHW) is a safe and environmentally friendly disinfectant that has a potent and broad spectrum of antimicrobial activity against viruses, bacteria, and fungi. In this study, we aimed to investigate the effectiveness of SAHW against F. fujikuroi strains, including chemical fungicide-resistant strains, as an alternative to conventional chemical fungicides in the management of bakanae disease. SAHW showed strong but similar levels of antifungal activity among the F. fujikuroi strains with a minimum inhibitory concentration (MIC₉₀) of 5±2.5 ppm of free available chlorine (FAC). In addition, F. fujikuroi cells lost viability completely within 5 min of SAHW treatment due to the lethal damage to cell integrity. When the rice seeds infected by F. fujikuroi were treated with SAHW containing 20±10 ppm of FAC for 12 hr, the efficiencies of seed disinfection and disease control were 95-98% and 90.1-92.6%, respectively. Altogether, our data suggest that SAHW is an effective compound for controlling rice bakanae disease.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.4
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• pp.276-282
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• 2013

The reclaimed water has been highlighted as a representative alternative to solve the lacking water resources. This study examined the reduction of residual free chlorine by temperature (5, 15, $25^{\circ}C$) and initial injection concentration (1, 2, 4, 6 mg/L) in the reclaimed water and carried out propose on the calculating method of the optimal chlorine dosage. As the reclaimed water showed a very fast reaction with chlorine at the intial time comparing to that of drinking water, the existing general first-order decay model ($C_t=C_o(e^{-k_bt})$) was not suitable for use. Accordingly, the reduction of residual free chlorine could be estimated in a more accurate way as a result of applying the exponential first-order decay model ($C_t=a+b(e^{-k_bt})$). ($r^2$=0.872~0.988). As a result of calculating the bulk decay constant, it showed the highest result at 653 $day^{-1}$ under the condition of 1 mg/L, $25^{\circ}C$ for the initial injection whereas it showed the lowest result at 3.42 $day^{-1}$ under the condition of 6 mg/L, $5^{\circ}C$ for the initial injection. The bulk decay constant tends to increase as temperature increases, whereas the bulk decay constant tends to decrease as the initial injection concentration increases. More accurate calculation for optimal chlorine dosage could be done by using the experimental results for 30~5,040 min, after the entire response time is classified into 0~30 min and 30~5,040 min to calculate the optimal chlorine dosage. In addition, as a result of calculating the optimal chlorine dosage by temperature, the relationships of initial chlorine demand (y) by temperature (x) could be obtained such as y=1.409+0.450x to maintain 0.2 mg/L of residual free chlorine at the time after 4 hours from the chlorine injection.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.37-45
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• 2015

In this experimental study, effect of milled glass fibers was investigated on corrosion resistance of PSC grout mortar. In order to check whether the mortar mixture with milled glass fibers satisfy the required properties as a PSC grout, time of flow, bleeding and compressive strength measured. The corrosion resistance were investigated through chloride ion migration test, mortar absorption test and surface resistivity measurement. It is confirmed that all proportions with milled glass fibers have better corrosion resistance than that with only OPC binder. Time of flow was reduced but the bleeding was increased to unacceptable level by using milled glass fibers. Consequently, the mix proportion with milled glass fibers for a PSC grout should be modified to have lower water/binder ratio.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.490-490
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• 2021

상수도 관망은 대표적인 사회기반시설로 수원으로부터 수용가에게 수질적으로 안전한 물을 안정하게 공급하는 것을 목표로 한다. 초기의 상수도 관망의 최적 설계는 비용만을 고려함으로써 미래의 불확실한 상황에 대한 대처가 매우 취약하고, 사용자의 다양한 요구를 충족시키지 못하였다. 또한, 유량과 안정적인 수질 공급을 고려하는 설계는 몇몇 비선형적 요소를 포함하고 있으며, 특히 사용자의 수요 패턴에 따른 잔류 염소 농도가 설계 기준에 부합하지 못하는 문제가 되는 경우 사용자의 심미적, 심리적 불편을 초래할 수 있다. 이는, 수질의 안전성과 직결되는 문제이다. 따라서 본 연구에서는 상수도 관망의 설계에 대하여 수질과 수리학적 특성을 고려한 상수도 관망 다목적 최적 설계를 수행하였다. 상수도 관망은 수질적인 측면을 고려하기 위해 수원에서 수용가까지 용수를 공급하는 과정에서 병원성 미생물을 소독하기 위하여 염소를 주입한다. 또한, 유리 잔류 염소의 평상시 기준을 (1.0-4.0mg/L) 유지하도록 규정하였다 (수도법 시행규칙 제22조의2). 하지만 사용자의 사용패턴, 체류 시간에 따라 잔류염소량이 달라진다. 따라서, 본 연구에서는 상수도 관망의 설계 비용과 염소 주입량을 동시에 설계 인자로서 고려하기 위해 Multi-objective Harmony Search를 적용하고, 그 결과를 분석하였다. 이러한 상수도 관망의 수질 인자와 설계 비용을 고려한 최적 설계안은 경제적 측면 뿐만 아니라 사용자의 수질 측면의 안전성을 충족하는 방안을 제시할 수 있다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.255-259
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• 1979

Depuration of extraneous substances such as bottom deposit, feces and coliforms from live oyster has been studied. Coliform accumulation of bottom cultured oysters was much higher than that of raft or long line cultured oysters. When the depuration tank designed in this study was adopted, the depuration rate could be diminished to about $50\%$ within one hour treatment. Tho most effective conditions of the tank water for depurating live oysters wer $22^{\circ}C$ in temperature, 8.80 in pH and below about 2 ppm of residual chlorine concentration.