• 한국수처리학회지
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• 제26권6호
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• pp.99-107
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• 2018

This research has developed a high temperature steam cleaning technology using a ceramic membrane with durability against temperature and pressure conditions. In steam cleaning, steam of $120^{\circ}C$ is injected into the ceramic membrane to induce pyrolysis by the endothermic reaction to remove fouling from the membrane. The water quality of raw water was adjusted to turbidity 10, 25 NTU and DOC 2.5 mg/L, and the membrane was uniformly fouled by constant pressure operation at 100, 200, and 300 kPa. Physical backwashing was performed with water and air at a pressure of 500 kPa and steam at $120^{\circ}C$ was injected for 0 to 5 minutes. As the turbidity concentration and the operating pressure increased, the flux decreased by 0.7 to 14.4%. It is confirmed that 10.7 to 53.8% recovery is possible than physical cleaning at the injection of steam for 3 minutes, so it is considered that the steam cleaning of the ceramic membrane is effective. Compared with CEB after NaOCl (300 mg/L) filtration at 25 NTU and 300 kPa of turbidity, the steam cleaning result for 3 minutes was similar to 46.7% of CEB for 3 hours. It has been confirmed that steam cleaning is suitable for a ceramic membrane having excellent heat resistance against high temperature. It was considered to have better cleaning efficiency as compared with general physical backwashing.

• 헤리티지:역사와 과학
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• 제46권1호
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• pp.228-237
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• 2013

지류문화재는 유기질이라는 재질의 특성상 시간이 지나면서 여러 가지 복합적인 손상인자(물리적 화학적 생물학적 인위적 원인)에 의해 유물의 보존성에 영향을 받고 있다. 그리하여 그 손상 정도에 따라 적절한 보존처리를 실시하게 되는데 그중 유물의 오염원을 제거하는 습식클리닝 처리가 지류문화재를 구성하는 주 원료인 한지의 재질에 미치는 영향을 분석해 보고자 본 연구를 실시하였다. 분석방법은 공시재료로 인공열화지를 사용하였고 습식클리닝(침적식)을 적용하여 처리 전 후의 색차와, 내절강도를 분석하였다. 분석결과 습식클리닝(침적식)에 의한 색도의 변화와 내절강도는 30분 침적을 2회 반복 처리하였을 때 가장 높은 수치를 나타냈다. 따라서 이때가 클리닝의 효율과 재질의 안정성이 가장 양호함을 알 수 있었다.

• 상하수도학회지
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• 제35권6호
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• pp.425-436
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• 2021

In this study, chemically enhanced steam cleaning(CESC) was applied as a novel and efficient method for the control of organic and inorganic fouling in ceramic membrane filtration. The constant filtration regression model and the resistance in series model(RISM) were used to investigate the membrane fouling mechanisms. For total filtration, the coefficient of determination(R²) with an approximate value of 1 was obtained in the intermediate blocking model which is considered as the dominant contamination mechanism. In addition, most of the coefficient values showed similar values and this means that the complex fouling was formed during the filtration period. In the RISM, R _c/R _f increased about 4.37 times in chemically enhanced steam cleaning compared to physical backwashing, which implies that the internal fouling resistance was converted to cake layer resistance, so that the membrane fouling hardly to be removed by physical backwashing could be efficiently removed by chemically enhanced steam cleaning. The results of flux recovery rate showed that high-temperature steam may loosen the structure of the membrane cake layer due to the increase in diffusivity and solubility of chemicals and finally enhance the cleaning effect. As a consequence, it is expected that chemically enhanced steam cleaning can drastically improve the efficiency of membrane filtration process when the characteristics of the foulant are identified.

• 멤브레인
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• 제29권6호
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• pp.339-347
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• 2019

정삼투 공정(forward osmosis, FO)은 역삼투 공정(reverse osmosis, RO)에 비해 저압으로 운영되므로 오염 제어, 유지 보수, 막 세정 및 잠재적 에너지 저감 측면에서 큰 이점이 있어 다양한 분야에 적용할 수 있는 기술이다. 특히, 정삼투 공정의 막오염층이 비교적 느슨하고 분산된 특성을 가지므로 역삼투 공정과 달리 물리세정만으로도 충분한 막오염 제어가 가능하다. 하지만 기존 연구들의 경우 정삼투 물리세정에 적합한 세정 유속을 적용하지 않아 최적화 운전을 하지 못했다는 한계가 있다. 따라서 이 연구는 경제적인 에너지량으로 높은 효율의 세정을 보일 수 있는 적절한 유속의 정당성 평가를 목적으로 한다. 정삼투 공정 막오염 실험을 8.54 cm/s 순환 유속으로 유지하고 세 가지 세정유속으로 회복률과 SEC (specific energy consumption) 비교 평가하였다. 이 실험의 결과로 2배속 세정이 3배속 세정의 수투과도 회복률 만큼의 높은 효율을 보이는 동시에, 2배속 세정이 높은 세정효율 및 경제적인 SEC를 보이는 적절한 유속이라는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제11권3호
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• pp.795-801
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• 2010

LCD (Liquid Crystal Display) 제조기술이 발전함에 따라 유리기판은 점차 대형화되는 추세이고 제조공정도 세밀화되어 감에 따라 LCD 제조과정에서 세정공정의 중요성이 부각되고 있다. 본 연구에서는 물리적 세정방법 중 브러쉬 (brush), 버블제트 (bubble jet) 및 이류체 (aqua/air) 세정법을 이용하여 미립자 (particles) 제거효율을 비교 평가하였다. 7세대 LCD 유리기판 ($1875\;mm\;{\times}\;2200\;mm$)을 대상으로 초순수 (deionized water)의 유량 및 압력 변화와 브러쉬의 모(毛)와 유리기판과의 접촉깊이 (contact depth) 등의 운전조건 변화를 통하여 미립자의 제거효율을 비교하였고 각 세정법에 의한 유의차 분석을 통해 향후 세정장비 개발에 유용한 자료로 활용하고자 하였다. 브러쉬 세정의 경우 브러쉬 접촉깊이에 변화를 주었을 때 임계점부터는 세정효율에 유의차가 크지 않음을 알 수 있었다. 버블제트 세정은 압력변화에 따른 세정력 유의차가 거의 없음을 관찰할 수 있었으며, 이류체 세정은 압력변화시 임계점까지는 세정력 유의차가 존재하나 임계점 이후부터는 유의차가 발생하지 않았다. 상기 3가지 세정방법 중 브러쉬 세정이 주어진 조건에서는 세정효과가 가장 큰 것으로 나타났다.

• 마이크로전자및패키징학회지
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• 제16권1호
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• pp.45-50
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• 2009

레이저를 이용 실리콘 관통형 접속기술인 TSV(Through-Silicon-Via)를 형성할 경우 Debris(파편물) 및 Particle이 발생되므로 이를 제거하기 위한 세정공정을 연구하였다. 계면활성제를 이용한 화학적 세정과 Brush를 이용한 물리적 세정을 검토하기 위하여 세정기를 제작하고 8인치 CMOS Image Sensor wafer에 직경 $30{\mu}m$, 깊이 $100{\mu}m$를 갖는 Via를 제작하여 두 가지의 세정방법을 연구하였다. 세정액은 DI Water와 계면활성제의 혼합비 2:1에서 Debris 범위가 $73{\mu}m^2$로 희석비가 낮을수록 세정력이 우수하였다. 레이저의 주파수와 속도변위에 따른 가공 조건 변화에는 Debris 분포차가 5% 미만으로 세정력에는 영향이 없었다. Brush를 이용하여 Debris를 제거하는 실험에서 Strip $1000{\sim}3000rpm$, Rinse $50{\sim}3000rpm$, Brush $200{\sim}300rpm$ 으로 증가시켜 세정하였을 때 Crack이나 손상 없이 Debris의 분포가 감소하였다. 따라서 화학적 세정과 물리적 세정으로 Debris를 제거할 수 있다.

• Environmental Engineering Research
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• 제23권4호
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• pp.474-484
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• 2018

The cleaning efficiency of reverse osmosis (RO) membranes inevitably fouled by organic foulants depends upon both chemical (type of cleaning agent, concentration of cleaning solution) and physical (cleaning time, flowrate, temperature) parameters. In attempting to determine the optimal procedures for chemical cleaning organic-fouled RO membranes, the design of experiments concept was employed to evaluate key factors and to predict the flux recovery rate (FRR) after chemical cleaning. From experimental results and based on the predicted FRR of cleaning obtained using the Central Composite Design of Minitab 17, a modified regression model equation was established to explain the chemical cleaning efficiency; the resultant regression coefficient ($R^2$) and adjusted $R^2$ were 83.95% and 76.82%, respectively. Then, using the optimized conditions of chemical cleaning derived from the response optimizer tool (cleaning with 0.68 wt% disodium ethylenediaminetetraacetic acid for 20 min at $20^{\circ}C$ with a flowrate of 409 mL/min), a flux recovery of 86.6% was expected. Overall, the results obtained by these experiments confirmed that the equation was adequate for predicting the chemical cleaning efficiency with regards to organic membrane fouling.

• Safety and Health at Work
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• 제7권4호
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• pp.389-393
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• 2016

Job hazard analyses were conducted to assess exposure to musculoskeletal disorder (MSD) risk factors in seven workers of three dry-cleaning establishments. In accordance with the Washington State Ergonomics Rule, the analyses were performed in two separate steps: (1) observation and checklist approaches were made to identify a "caution zone job" in the seven workers' pressing operations across the three shops; and (2) detailed posture and motion analyses were undertaken to determine a "MSD hazard" in one worker's operation using a video technique. One "caution zone job" was identified and it was the pressing operation job in which five physical risk factors were found in the pressing operations. The detailed analyses confirmed that one "MSD hazard", i.e., awkward posture in shoulders, was prevalent in the pressing operations of the three dry-cleaning facilities. It would be desirable to reduce MSD risk factors including awkward shoulder posture in the dry-cleaning industry.

• 한국응용과학기술학회지
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• 제27권2호
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• pp.107-113
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• 2010

The object of this research is to conform of practicable possibility and recycling of producing junk after citrus fruits is processed. With extracting d-limonene oil that have 70~90% a component of oil out of junk citrus peel, making certain the about 12000ppm concentration of it. Limonene derived from citrus in jeju using conventional synthetic detergents can be replaced with the development of environmentally friendly natural detergent investigated the possibility. Mostly due to ocean dumping, disposal and cause environmental problems by recycling natural citrus cleaner alternative to the research conducted on the possibility. Cleaning efficiency with temperature did not affect the largest concentrations were able to identify the difference between cleaning efficiency. At least 10% of the d-limonene oil could be from the cleaning performance, increasing the concentration of the cleaning efficiency was increased in size. Ultrasonic is very high removal efficiency under the conditions shown in the cause of pure self-generated ultrasonic cleaning power as co-effects of d-limonene oil appears to chemical cleaning effect of ultrasonic cavitation occurs in the physical cleaning effect due to a combination of synergistic stability is maximized by low concentrations of d-limonene oil in a short time showed an excellent cleaning ability. Having the ability of cleaning at the same time, considering the side recycling in the junk citrus peels reflects possibility of basic materials utility eco-friendly in the skin soap, bath soap, cosmetics etc, through ability of exclusion a contaminant in based cleaning effect(EC) it can prospect substitution effect environmentally in the pre existence synthetic detergents.

• 한국디지털건축인테리어학회논문집
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• 제13권4호
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• pp.61-68
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• 2013

Concrete structure is not the only material vulnerable to physical and chemical processes of deterioration associates with severe conditions. Deterioration of the concrete structure, however, occurs more progressively from the outside of the concrete exposed to severe conditions. Especially, Carbonation, chloride ion attack is more important factor of concrete durability. This study is interested in manufacturing the self-cleaning concrete surface impregnant including TEOS, lithium silicate for the repair of the exposed concrete surface and the color concrete requiring the advanced function in view of the concrete appearance. Form the results, TEOS and lithium silicate are very effective that increasing the concrete durability using self-cleaning concrete impregnant. Self-cleaning concrete impregnant specimens is satisfied with performance requirement of KS standard in adhesion test in tension but the reinforcement of concrete substrate is slight. So, the self-cleaning concrete impregnant of this study is more desirable for the improvement of durability rather than the reinforcement.