지하수를 식수원으로 활용하고 있는 대부분의 소규모 마을상수도 시설에서 방사성물질 발현에 대한 문제가 지속적으로 재기됨에 따라, 2015년 수질감시기준에 우라늄 항목이 추가되었다. 효과적인 우라늄 처리를 위하여, 마을상수도 시설에 NF 및 RO를 이용한 처리공정의 적용이 증가하고 있으나, 적용된 분리막의 효율적인 관리방법이 미흡한 현실이다. 전문적인 운영관리인원이 부족한 현실에서 안정적인 RO공정의 운영을 위한 방안으로 분리막의 세척방안 마련이 필요하다. 이를 위하여 본 연구에서는 RO공정을 마을상수도에 도입시키고 운영하며, 발생되는 RO 분리막 오염의 효과적인 제어방법을 도출코자 하였다. 효율적인 세척방법으로 산/염기의 순차적 세척방법이 도출되었으며, 약 93%의 분리막 세척효과를 확인하였다.

This study involved the shape of water jet nozzle to promote blasting ability and an increase of projection distance when cleaning VLBC cargo hold. Simulation of water jet projection process inside VLBC cargo hold was done in both 2D and 3D environment. The result are promising since both case show the capability of water contacting the desired target.

Pellicle is defined as a thin transparent film stretched over an aluminum (Al) frame that is glued on one side of a photomask. As semiconductor devices are pursuing higher levels of integration and higher resolution patterns, the cleaning of the Al flame surface is becoming a critical step because the contaminants on the Al flame can cause lithography exposure defects on the wafers. In order to remove these contaminants from the Al frame, a highly concentrated nitric acid (HNO3) solution is used. However, it is difficult to fully remove them, which results in an increase in the Al surface roughness. In this paper, the pellicle frame cleaning is investigated using various cleaning solutions. When the mixture of sulfuric acid (H2SO4), hydrofluoric acid (HF), hydrogen peroxide (H2O2), and deionized water with ultrasonic is used, a high cleaning efficiency is achieved without HNO3. Thus, this cleaning process is suitable for Al frame cleaning and it can also reduce the use of chemicals.

Deposits discharged through the cleaning mainly were cement mortar, bitumen paintings and rust pieces, and fragments of perforation, stones and gravels. Deposits were more removed through swabbing pig cleaning rather than air scouring cleaning on the whole. However, air scouring cleaning were not influenced by the constraint conditions such as a change in the diameter or the presence of the valve in water mains compare to swabbing pig cleaning. So, it was thought that air scouring cleaning might be more favorable to water distribution network cleaning in the future. After the cleaning, water quality including residual chlorine and turbidity also was improved because of the removal of a significant amount of the deposits. Therefore, if the cleaning is continuously and regularly implemented in water mains, it is expected that it will help to recover the reliability and to preserve the health of water quality.

This study involved the shape of water jet nozzle to promote blasting ability and an increase of projection distance when cleaning VLBC cargo hold. Furthermore, I researched the effect of pressure, length of reducer, nozzle caliber size and nozzle shape on the nozzle through CFD simulation. Simulation of water jet projection process inside VLBC cargo hold was done in both 2D and 3D environment. Simulation results show installing suitable nozzle can increase the cleaning effect of cargo hold.

Membrane biofouling is the major concern to be addressed in membrane bioreactors (MBRs). Synergistic combinations of quorum quenching and physical cleaning methods were applied to minimize membrane fouling in MBRs. Different types of physical cleaning modes, such as relaxation, air backpulsing, and permeate backwashing were used in combination with quorum quenching. A significant improvement in fouling control was accomplished when QQ was coupled with physical cleaning methods, especially in relaxation. In addition, mixed liquor properties and treatment performances were not affected by the QQ activity. This research was supported by a grant (2012001440001) from the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.

Polytetrafluoroethylene (PTFE) membrane has high resistance to chlorine, which is a great advantages in chemical cleaning to recover water flux during membrane processes in drinking water systems. A humic kaolin water with approximately 4 mg/L of DOC and 10 NTU of turbidity was prepared as a feed water. Coagulation pretreatment with or without settling was applied. The coagulation with settling showed the greatest water production. The reduced flux was effectively recovered by NaOCl cleaning, i.e., 21% recovery by 50 mg/L of NaOCl cleaning and 49% recovery by 500 mg/L NaOCl cleaning. The images of SEM and AFM analyses were corresponded to the water flux variation. However, when the floc was accumulated on the membrane surfaces, the efficiency of NaOCl cleaning was substantially limited. In addition, dynamic contact angle became greater after cleaning, which indicates changes in characteristics of fouling layer such as surface hydrophobicity. Proper cleaning technologies during enhanced backwash using NaOCl would expand application of PTFE membranes in drinking water systems.

The development of a high pressure cleaning system is needed to properly clean cargo hold and improve the working environment of a ship. For this, the study on the parameters related to the suitable capacity of a pressure pump should be preceded.

The flushing is important to maintain good water quality in water main. It is a technique of using water velocity to remove sediments in water distribution system. The variety of water quality problems can occur in a distribution system, so too can a variety of benefits be gained by system flushing. In order to effectively perform the flushing, the contaminants to be removed to set up and it can be solved, it is necessary to ensure the proper flow rate. In this study, the removal of contaminants present in the inner water pipe attached loose deposits such as fine particles of granular activated carbon, sand and iron corrosion product sought to derive flow rates. Thus, the constant observation of using pilot plant scale water distribution plant for the movement of floating characteristics of particles were assessed.

As the fabrication technology used in FPDs(flat-panel displays) advances, the size of these panels is increasing and the pattern size is decreasing to the um range. Accordingly, a cleaning process during the FPD fabrication process is becoming more important to prevent yield reductions. The purpose of this study is to develop a FPD cleaning system and a cleaning process using a two-phase flow. The FPD cleaning system consists of two parts, one being a cleaning part which includes a two-phase flow nozzle, and the other being a drying part which includes an air-knife and a halogen lamp. To evaluate the particle removal efficiency by means of two-phase flow cleaning, silica particles 1.5μm in size were contaminated onto a six-inch silicon wafer and a four-inch glass wafer. We conducted cleaning processes under various conditions, i.e., DI water and nitrogen gas at different pressures, using a two-phase-flow nozzle with a gap distance between the nozzle and the substrate. The drying efficiency was also tested using the air-knife with a change in the gap distance between the air-knife and the substrate to remove the DI water which remained on the substrate after the two-phase-flow cleaning process. We obtained high efficiency in terms of particle removal as well as good drying efficiency through the optimized conditions of the two-phase-flow cleaning and air-knife processes.

목적: 착용 중인 안경렌즈에 대한 세균 오염정도를 확인하고 동시에 국내 최초로 유통되고 있는 1회용 안경렌즈 클리너(Lens Cleaning WIPE, ZEISS, Germany)에 대한 미생물학적 오염의 세척 효과를 검증하고자 하였다. 방법: 만 19세에서 만 38세 사이의 대학생 29명을 대상으로 착용 중인 안경렌즈에서 1회용 안경렌즈 클리너(Lens Cleaning WIPE, ZEISS, Germany)를 이용한 세척 전, 후에 대하여 멸균된 면봉으로 오염 균을 채취하였고 Thioglycollate Medium 수용성 배지와 혈액한천배지 및 MacConkey 배지에 접종하여 배양한 후 집락 수를 계산하였다. 세균의 동정은 Phoenix ID(BD Diagnostics, Inc. Sparks, Maryland, USA) 자동기기로 하였다. 결과: 세척 전 사용 중인 안경렌즈에서는 그람양성 알균이 6종으로 Streptococcus sp., Staphylococcus aureus, Staphylococcus hominis, Staphylococcus haemolyticus, Staphylococcus epidermidis, Micrococcus luteus가 검출되었으며 그람양성 막대균으로는 Bacillus cereus로 1종이 검출되었다. 1회용 안경렌즈 클리너를 이용하여 세척한 후에는 대부분 제거되었으나 Staphylococcus hominis와 Micrococcus luteus에서는 집락 수의 감소만 나타났다. 결 론: 본 실험에서는 사용 중인 안경렌즈에서 기회감염성 세균류인 그람양성 알균 6종과 그람양성 막대균 1종이 오염되었음을 확인하였다. 외부로 노출되어 있는 우리의 눈은 면역력이 떨어지거나 상처 등을 입었을 때 쉽게 감염을 일으킬 수 있는 기회감염성 균들에 대한 대안이 요구되는 현실에서 1회용 안경렌즈 클리너(Lens Cleaning WIPE, ZEISS, Germany)의 활용은 매우 유용한 것으로 판단된다.

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 확인 하였다.

As indoor air cleaners have large sizes and high air flow rates, the test methods for particle cleaning capacity need to be reconsidered because the prescribed test chamber size becomes relatively smaller. In this study, air flow rate of air cleaners compared to test chamber size (Q/V) has been investigated by comparing the short-circuit factor which indicates the air mixed condition in the test chamber. The test method of Korea Air Cleaning Association (KACA) has been analysed and compared to that of Association of Home Appliance Manufacturers (AHAM) for clean air delivery rate (CADR) of two household air conditioners equipped with air cleaners having a maximum air flow rate of 15 m³/min in terms of initial particle concentrations, neutralized/non-charged particles, delay time before acquiring initial particle concentration, sampling positions. Constant short-circuit factor of about 0.9 was obtained in the range of Q/V less than 0.73 min^-1. CADR based on KACA test method was somewhat dependent on initial particle concentrations, delay time before acquiring initial concentration, sampling positions. However, CADR based on AHAM test method was less dependent. Two or three minutes of delay time before acquiring initial concentration was necessary to reduce the variation of CADR according to initial particle concentration and sampling position.

본 연구는 Y 정수장의 세라믹 정밀여과막 공정을 위한 최적의 약품세척 조건을 도출하고자 수행되었다. 세라믹 막 공정의 전처리로 오존과 응집공정이 있는 A계열의 경우 응집공정만 있는 B계열에 비해 9배 정도 잦은 약품세척(CIP)를 실시하였다. 이는 전처리 공정의 차이로 인하여 A와 B계열의 막오염현상이 다르게 나타난 근본적인 원인 이외에 막제조업체가 제시한 CIP 방법이 부적절한 것으로 조사되었다. 즉, CIP 회복률이 보정여과유속이 아니라 보정차압을 기준으로 계산되어 과대평가되었을 뿐만 아니라 구연산이 철산화물에 의한 파울링을 효과적으로 제거하지 못했기 때문이었다. 따라서 1단계 산세척 약품종류를 달리하여 CIP 효율을 평가한 결과 황산(0.1 N)과 구연산(1%)를 혼합하여 사용한 경우 회복률이 가장 높았고, 황산(0.1 N)만을 사용한 경우 회복률이 가장 낮은 것으로 나타났다. 그러나 황산의 농도를 0.3 N로 높인 결과 산세척 효율은 증가하였으나 알칼리세척 회복률이 낮아져 총회복률은 0.1 N 황산을 사용한 것과 유사하였다. 산과 알칼리세척 순서를 바꿔서 CIP를 수행한 결과 산세척을 먼저 수행시 CIP 효율이 더 높은 것으로 나타났다.

We investigated cleaning effects using NH4OH solution on the surface of Cu film. A 20 nm Cu film was deposited on Ti / p-Si (100) by sputter deposition and was exposed to air for growth of the native Cu oxide. In order to remove the Cu native oxide, an NH4OH cleaning process with and without TS-40A pre-treatment was carried out. After the NH4OH cleaning without TS-40A pretreatment, the sheet resistance Rs of the Cu film and the surface morphology changed slightly(δRs:~10mΩ/sq.). On the other hand, after NH4OH cleaning with TS-40A pretreatment, the Rs of the Cu film changed abruptly (δRs:till~700mΩ/sq.); in addition, cracks showed on the surface of the Cu film. According to XPS results, Si ingredient was detected on the surface of all Cu films pretreated with TS-40A. This Si ingredient(a kind of silicate) may result from the TS-40A solution, because sodium metasilicate is included in TS-40A as an alkaline degreasing agent. Finally, we found that the NH4OH cleaning process without pretreatment using an alkaline cleanser containing a silicate ingredient is more useful at removing Cu oxides on Cu film. In addition, we found that in the NH4OH cleaning process, an alkaline cleanser like Metex TS-40A, containing sodium metasilicate, can cause cracks on the surface of Cu film.

Particle collection efficiency and air cleaning capacity were tested for the two-stage electrostatic precipitator for use in indoor air cleaning systems. A wire-plate type ionizer was used as a particle charger and a dielectric film consisted of polypropylene (or polyethylene) coated metals and zigzagged metal electrodes was used as a particle collector in the electrostatic precipitator. Both particle collection efficiency and air cleaning capacity increased as increasing the applied voltage on the charger and the collector, and furthermore, as increasing the collector film width (i.e. collection area). Air cleaning capacities estimated by the product of particle collection efficiency and air flow rate were quite well consistent with the experimental ones with a proportional constant of 0.964. Ozone concentrations emitted from the charger at the applied voltages of 5.0 and 5.2 kV were less than 0.05 ppm, indoor ozone standards of UL 867-2002, KS C 9314 and SPS-KACA002-132. For the air flow rate of 11.7 m³/min, the applied floor area of 48.2 m² could be obtained when 5.2 kV and 6.0 kV were applied on the ionizer and the collector, respectively and the collector of two 15 mm polyethylene dielectric films was used.

Recently nanoscience and nanotechnology have been studied intensively, and many plants, insects, and animals in nature have been found to have nanostructures in their bodies. Among them, lotus leaves have a unique nanostructure and microstructure in combination and show superhydrophobicity and a self-cleaning function to wipe and clean impurities on their surfaces. Coating films with combined nanostructures and microstructures resembling those of lotus leaves may also have superhydrophobicity and self-cleaning functions; as a result, they could be used in various applications, such as in outfits, tents, building walls, or exterior surfaces of transportation vehicles like cars, ships, or airplanes. In this study, coating films were prepared by dip coating method using polypropylene polymers dissolved in a mixture of solvent, xylene and non-solvent, methylethylketon, and ethanol. Additionally, attempts were made to prepare nanostructures on top of microstructures by coating with the same coating solution with an addition of carbon nanotubes, or by applying a carbon nanotube over-coat on polymer coating films. Coating films prepared without carbon nanotubes were found to have superhydrophobicity, with a water contact angle of 152˚ and sliding angle less than 2˚. Coating films prepared with carbon nanotubes were also found to have a similar degree of superhydrophobicity, with a water contact angle of 150 degrees and a sliding angle of 3 degrees.

This study was conducted to determine cleaning effects of environmental-friendly washing detergent on milking installation in dairy farms. Milking machine, cooling machine and milking liner were washed by alkaline detergent and acid detergent for first three weeks and alkaline detergent and environmental-friendly detergent for next three weeks and the results get through microorganism and physico-chemistry analysis at the five district dairy farms different from environment. E-coli, coliform, fecal coliform, staphylococcus aureus, fecal streptococcus, prsudomonas aeruginosa and yersinia were not found in all of the dairy farms, and total colony counts were no difference compared with chemical detergent. The water for washing exceeded the determining acceptable level of nitrate nitrogen in the Anseong, Onyang and Cheonan and the remaining substance of washed water was also high levels. The cause of the result was that the level of nitrate nitrogen of water is basically high. Therefore, this study indicated that washing effect is no differences between environmental-friendly detergent and chemical detergent by washing for milking machine and cooling machine. Above all, producing high quality milk is to manage the water quality as well as using detergent.

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.

This paper investigates the dependence of a-Si:H/c-Si passivation and heterojunction solar cell performances on various cleaning processes of silicon wafers. It is observed that the passivation quality of a-Si:H thin-films on c-Si wafers depends highly on the initial H-termination properties of the wafer surface. The effective minority carrier lifetime (MCLT) of highly H-terminated wafer is beneficial for obtaining high quality passivation of a-Si:H/c-Si. The wafers passivated by p(n)-doped a-Si:H layers have low MCLT regardless of the initial H-termination quality. On the other hand, the MCLT of wafers incorporating intrinsic (i) a-Si:H as a passivation layer shows sensitive variation with initial cleaning and H-termination schemes. By applying the improved cleaning processes, we can obtain an MCLT of 100μsec after H-termination and above 600μsec after i a-Si:H thin film deposition. By adapting improved cleaning processes and by improving passivation and doped layers, we can fabricate a-Si:H/c-Si heterojunction solar cells with an active area conversion efficiency of 18.42%, which cells have an open circuit voltage of 0.670V, short circuit current of 37.31 mA/cm2 and fill factor of 0.7374. These cells show more than 20% pseudo efficiency measured by Suns-Voc with an elimination of series resistance.