• Membrane and Water Treatment
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• 제2권3호
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• pp.147-158
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• 2011

Membrane distillation process was used for desalination of hot (333 K) geothermal water, which was applied in the plant producing heating water. The investigated water contained 120 g salts/$dm^3$, mainly NaCl. The mineral composition was studied using an ion chromatography method. The obtained rejection of solutes was closed to 100%, but the small amounts of $NH_3$ also diffused through the membrane together with water vapour. However, the composition of obtained distillate allowed to use it as a makeup water in the heating water system. The geothermal water under study was concentrated from 120 to 286 g NaCl/$dm^3$. This increase in the solution concentration caused the permeate flux decline by a 10-20%. The geothermal water contained sulphates, which was subjected to two-fold concentration to achieve the concentration 2.4-2.6 g $SO{_4}{^{2-}}/dm^3$ and the sulphates then crystallized in the form of calcium sulphate. As a results, an intensive membranes scaling and the permeate flux decline was observed. The XRD analysis indicated that beside the gypsum also the NaCl crystallites were deposited on the membrane surfaces. The fresh geothermal water dissolved the mixed $CaSO_4$ and NaCl deposit from the membrane surface. This property can be utilized for self-cleaning of MD modules. Using a batch feeding of MD installation, the concentration of geothermal water was carried out over 800 h, without significant performance losses.

• Carbon letters
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• 제26권
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• pp.74-80
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• 2018

The South Korean Ministry of the Environment has revised the laws relating to the management of interior air quality for multiple use facilities, and recommends maintaining carbon dioxide ($CO_2$) concentration in passenger vehicles below 1000 ppm during operation in urban areas of large cities. However, the interior $CO_2$ concentration of passenger vehicles can rapidly increase and exceed 5000 ppm within 30 min, as observed when two passengers are traveling in urban areas of the South Korean city of Jeonju with the air conditioner blower turned off and the actuator mode set to internal circulation mode. With four passengers, $CO_2$ concentration can reach up to 6000 ppm within 10 min. To counter this, when the actuator is set to external mode, $CO_2$ concentration can be maintained below 1000 ppm, even after a long period of running time. As part of the air conditioning system, alkali-treated activated carbon fiber filters are considered to be far superior to the commercial non-woven filters or combination filters currently commonly in use.

• 한국의류학회지
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• 제19권6호
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• pp.955-967
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• 1995

This study was performed to investigate the physical and chemical properties of the 5 kinds of fabrics dyed with persimmon juice and undyed fabrics. The difference between dyed and undyed fabrics was checked experimentally. Obtained results are as follows. 1. Bending length and flex stiffness were increased after dyeing, and tensile strength of waif i3l fabrics except Ramie was also increased. 2. Abrasion resistance was improved in Ramie and Hemp after dyeing but the rest of fabrics were decreased. 3. Crease resistance of dyed fabrics was roughly worse than that of undyed fabrics. 4. Air permeability remarkably increased after dyeing and this fact estabilished that the traditional Gal-01 was cool clothing. 5. Water repellency in Cotton 1 and Polyester rises but the rest of fabrics were not changed. Therefore it is found that this repellency related to the their fabric counts. 6. Blocking effect of UV light and visible ray was increased in all dyed fabrics. Especially dyed Cotton 1 and Polyester blocked UV light almost perfectly. 7. The colorfastness to soaping and sunlight was proved to less than 3 grade in all fabrics after dyeing. It indicates that this colorfastness became worse owing to dyeing. 8. The colorfastness to dry cleaning and water was decided to more than 3 grade in all fabrics. 9. The colorfastness of the dyed fabrics to sweat after exposing to man-made acid sweat solution was good so that was decided above 3 grade. However after exposing to man-made alkalic sweat solution it became worse owing to dyeing.

• 한국축산식품학회지
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• 제29권4호
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• pp.513-522
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• 2009

HACCP is a scientific and systematic program that identifies specific hazards and gives measures for their control to ensure the safety of foods. Based on the Livestock Products Processing Act, the HACCP system is now being applied to Korean livestock products since December 1997, and Korea is accelerating its application from farm to table, including in farms, slaughterhouses, livestock product industries, retail markets, and transportation. The transport of livestock and its products is one of the vulnerable sectors in terms of food safety in Korea. Meats are transported in trucks in the form of carcasses or packaged meats in boxes. Carcasses may be exposed to microbiological, physical, and chemical hazards from the environment or through cross-contamination from other meats. Poor cleaning or maintenance of vehicles and tools may also raise the exposure of carcasses to microbiological or chemical hazards. HACCP application and its acceleration in distribution, particularly in transport, is regarded as critical to the provision to consumers of ultimately safe livestock products. To achieve this goal, steady efforts to develop practical tools for HACCP application should be carried out.

• 한국안전학회지
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• 제17권3호
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• pp.112-117
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• 2002

무성 (유전체 장벽)방전기구의 질소산화물(NOx)제거효율에 대한 화학 반응역학의 전산모사 및 실험적 특성이 비교 조사되었다. 방전 전극구조에 따른 여러 종류의 유전체 장벽 방전기구가 구현되었으며 응용 방전환경 별 질소산화물(NOx)제거특성이 이론적, 실험적으로 고찰되었다. 전산모사 모델링은 유해 배가스에 대한 플라즈마 응용기구의 수학적 근접모델을 기초로 하였고 각 방전광(스트리머) 채널의 주 활성입자 생성에 의한 화학반응 종들의 비균일, 비평형 분포특성을 고려하였다. 모델링 전산모사로 얻어진 질소산화물(NOx) 제거효율은 관찰 실험특성과 오차 허용범위 내의 일치성을 나타내었다.

• Corrosion Science and Technology
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• 제10권1호
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• pp.24-29
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• 2011

The greatest purpose of chromate treatment is to improve anti-corrosion by stabilizing a metal surface. Because metal surface forms a compound by absorbing oxygen or water in the air by being generally unstable, it is necessary to improve anti-corrosion of the metal by forming the metal surface with a stable film. When considering the economical efficiency and requirements together because the film of the metal surface treated with chromate has good anti-corrosion and the stability also in the air by being compact and strong, Chromate treatment has been used most up to the electronics industry from the auto industry. However, these days, because hexavalent chromium is both a toxic agent to be able to cause cancers and deadly poisonous environmental pollutant, the strong legal controls on its use is being imposed all over the world. Because of this reason, a new anti-corrosion method is being required. Also, by users' various demands, the passivations that have recently been developed require various characteristics such as conductivity, chemical resistance, alkali cleaning resistance as well as anti-corrosion. We could confirm the results such as excellent anti-corrosion compared to chromate, conductivity, chemical resistance and detergent resistance as the result of analysis of various characteristics of the galvannealed sheet steels coated with Cr-Free solution developed in this research.

• 한국수소및신에너지학회논문집
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• 제25권2호
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• pp.145-150
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• 2014

This study investigates the preparation of anti-reflective (AR) coating film to improve the efficiency of solar cell. The AR coating film was successfully obtained by dip-coating with AR coatings prepared by sol-gel method. Fluoroalkylsilane was additionally introduced into the coatings to give the self-cleaning effect of AR coating film. We performed the abrasion test, pencil scratch hardness test and cross-cut test to identify the mechanical strength of AR coating film. As the results, the transmittance of AR coating films with 9.07, 18.13 and 27.20 of IPA/MTMS molar ratios were 93.1, 93.6 and 95.3%, respectively. The water contact angle and transmittance of AR coating film increased by the introduction of hydrophobicity. The prepared AR coating film shows the high level of abrasion, hardness and adhesion. The IPA/MTMS molar ratio of 27.20 and the withdrawing speed range of 0.20 ~ 0.28cm/sec are the optimal coating condition in terms of the transmittance and mechanical strength of AR coating film.

• 한국대기환경학회지
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• 제22권4호
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• pp.431-439
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• 2006

Catalytic oxidation of benzene, toluene and xylene (BTX) using regenerated metal oxide catalysts (ZnO-CuO, NiO, $Fe_2O_3$, ZnO, CrO) were investigated in a fixed bed flow reactor to evaluate their feasibility for the purpose of removing volatile organic compounds (VOCs). Four kinds of pre-treatment methods such as gas (air and hydrogen), acid aqueous solution, alkali aqueous solution and cleaning agent were used to find out the optimal regeneration conditions. The physico-chemical properties of the used and regenerated catalysts were characterized by BET and TPR (Temperature Programmed Reduction). The used catalysts showed high conversion ratio and the catalytic ability of toluene oxidation was in the order of ZnO-CuO>$Fe_2O_3$>NiO>ZnO>CrO. We found that the acid aqueous pre-treatment (0.1 N HNO$_3$) was the best way to enhance the catalytic activity of $Fe_2O_3$. In addition, air and hydrogen gas treatment were optimal for NiO and ZnO-CuO catalysts, respectively. Furthermore, the decomposition of BTX depends on the type of a catalyst and a gas molecule.

• 멤브레인
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• 제23권2호
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• pp.185-188
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• 2013

본 연구는 정밀여과용 관형 분리막 모듈 내에 자체 설계한 기체분사형 노즐을 장착하여 막오염 감소 효과에 따른 투과유속을 측정하였다. 원료 용액으로는 0.1 wt% yeast 입자를 사용하였으며 공기 주입에 따른 막오염 감소 효과를 확인하기 위하여 공기를 주입하지 않은 경우와 주입한 경우의 투과유속을 비교 분석하였다. 공기를 주입하지 않았을 경우 투과유속은 지속적으로 감소하였지만 공기를 주입할 경우 투과유속은 공기를 주입하지 않은 경우와 비교하여 30% 이상 향상됨을 확인하였다.

• 한국안전학회지
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• 제23권6호
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• pp.62-69
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• 2008

As the concerns of dermal exposure of spray painters to isocyanates in the automobile industry, glove performance was examined like permeation rate and breakthrough time including fatigue test. Methylene chloride was used as the solvent for derivatization of the isocyanates with a 97.5% recovery. Ghost wipe pads were used to wipe the surface of the glove material after chemical penetration through the glove material placed under a disposable test cell. Several solvents were tested, such as thinner(xylene, toluene) and cleaning agent(acetone) by using a standard permeation test cell(AS/NZS standard 2161. part 10.3). Solvents accelerate chemical permeation through the gloves more quickly than pure HDI hardener products. The longest breakthrough times were from Nitrosolve gloves, not detected in 8 hours, compared with others like Latex, Neoprene, TNT and Dermo Plus. Therefore Nitrosolve gloves could be recommended as personal protective equipment in crash repair shops. In addition, revised exposure limit of korean regulation should be suggested for employee to minimize the risk of health symptoms.