• Korean Journal of Materials Research
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• v.11 no.4
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• pp.251-257
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• 2001

A present semiconductor cleaning technology is based upon RCA cleaning, high temperature process which consumes vast chemicals and ultra Pure water(UPW). This technology gives rise to the many environmental issues, therefore some alternatives have been studied. In this study, intentionally contaminated Si wafers were cleaned using the electrolyzed water(EW). The EW was generated by an electrolysis equipment which was composed of anode. cathode, and toddle chambers. Oxidative water and reductive water were obtained in anode and cathode chambers, respectively. In case $NH_4$Cl electrolyte, the oxidation-reduction potential(ORP) and pH for anode water(AW) and cathode water(CW) were measured to be +1050mV and 4.7, and -750mV and 9.8, respectively. For cleaning metallic impurities, AW was confirmed to be more effective than that of CW, and the particle distribution after various particle removal processes was shown to be same distribution.

• Journal of Environmental Science International
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• v.25 no.6
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• pp.817-827
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• 2016

The resistance in series model has been frequently used for determination of various filtration resistance to correctly understand the membrane fouling behaviour in MBR (membrane bio-reactor) for wastewater treatment. The cake layer resistance ($R_c$) which is commonly determined by calculation of flux dataset that are obtained empirically before and after removing the cake layer on membrane surface. However, the calculated Rc values are very dependent on the cleaning methods adapted for removal of cake layer. This study investigated how the various cleaning options affect $R_c$. Seven different cleaning methods were employed: i) ultrasonication (100 W, 10 min), ii) ultrasonication (200 W, 60 min), iii) ultrasonication (400 W, 120 min), iv) water rinsing in a shaker (100 rpm, 10 min), v) water rinsing in a shaker (300 rpm, 60 min), vi) water rinsing, vii) sponge scrubbing. For the hydrophilic PES membrane, the cake layer removal efficiencies ranged from 64% to 10%, indicating that the removal of cake layer was highly dependent on the cleaning options. For the hydrophobic PVDF membrane, the cake layer removal efficiencies ranged from 79% to 97%. Consequently, a standardized method for cake layer removal to determine cake resistance ($R_c$) is needed for correct interpretation of the fouling phenomena.

• Journal of Marine Life Science
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• v.9 no.1
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• pp.1-8
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• 2024

Over the past decade, there has been global expansion in the advancement of underwater cleaning technology for ship hulls. This methodology ensures both diver safety and operational efficiency. However, recent attention has been drawn to the harmful effects of ship hull-cleaning wastewater on marine animals. It is anticipated that this wastewater may have various impacts on a wide range of organisms, potentially leading to populationand ecosystem-relevant alterations. This concern is especially significant when the wastewater affects functionally important species, such as aquaculture animals and habitat-forming species living in coastal regions, where underwater cleaning platforms are commonly established. Despite this, information on the ecotoxicological effects of this wastewater remains limited. In this mini review, we discuss the adverse effects of wastewater from in-water cleaning processes, as well as the current challenges and limitations in regulating and mitigating its potential toxicity. Overall, recent findings underscore the detrimental effects posed by sublethal levels of wastewater to the health status of aquatic animals under both acute and chronic exposure.

• Journal of the Korean Geosynthetics Society
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• v.23 no.2
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• pp.63-75
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• 2024

Drinking water is an essential element to ensure the basic human right to live, and the quality of clean water must always be ensured. However, domestic water facilities, which were installed intensively in the early 2000s, are deteriorating. The accidents such as discoloration of water such as chromaticity and turbidity as well as leakage of substances frequently occur. However, since it is virtually impossible to replace all water pipes, the detailed standards for maintenance of water pipe network facilities established in 2021 require water pipe cleaning. The swab pig method, one of the water pipe cleaning methods, is a method of physically removing substances in pipes and is evaluated as having the highest cleaning efficiency. However, Swab is highly likely to be damaged or deformed during the cleaning process, and may even be lost. Therefore, in this study, the material of the pig was changed to a material with high compressibility, and it was made as close as possible to the inner wall of the water pipe. And, to maximize cleaning efficiency, a rotation swab pig with a rotation blade was developed. In addition, high-strength wire and winding equipment were additionally developed to eliminate the possibility of loss and to determine the location of the pig. The inlet and outlet are connected with wires, and after verifying the performance of each detailed technology, the technology was applied on a test bed with a 30m section. As a result of the application, the performance of the technology was verified by measuring the process time and evaluating applicability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.94-98
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• 2012

The behavior of ozone micro bubble cleaning system was investigated to evaluate the solution as a new method of solar cell wafer cleaning in comparison with former conventional RCA cleaning. We have developed the ozone dissolution system in the ozonated water for more efficient cleaning conditions. The optimized cleaning conditions for solar cell wafer process were 10 ppm of ozone concentration and 12 minutes in cleaning periods, respectively. We have confirmed the cleaning reliability and cell efficiencies after ozone micro bubble cleaning. Using this new cleaning technology, it was possible to obtain higher efficiency, higher productivity, and fast tact time for applying cleaning in the fields on bare ingot wafer, LED wafers as well as the solar cell wafer.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.399-405
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• 2011

In a desalination technology using RO membranes, chemical cleaning makes damage for membrane surface and membrane life be shortened. In this research cleaning technology using direct osmosis (DO) was introduced to apply it under the condition of high pH and high concentration of feed. When the high concentration of feed is injected to the concentrate side after release of operating pressure, then backward flow occurred from treated water toward concentrated for osmotic pressure. This flow reduces fouling on the membrane surface. Namely, flux of DO was monitored under pH 3, 5, 10 and 12 conditions at feed concentrations of NaCl 40,000 mg/L, 120,000 mg/L and 160,000 mg/L. As a result, DO flux in pH 12 increased about 21% than pH 3. DO cleaning was performed under the concentrate NaCl 160,000 mg/L of pH 12 during 20 minutes. Three kinds of synthetic feed water were used as concentrates. They consisted of organic, inorganic and seawater; chemicals of SiO2 (200 mg/L), humic acid (50 mg/L) sodium alginate (50 mg/L) and seawater. As a result, fluxes were recovered to 17% in organic fouling, 15% in inorganic fouling and 14% of seawater fouling after cleaning using DO under the condition of concentrate NaCl 160,000 mg/L of pH 12.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.769-777
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• 2002

Using four components - nonionic surfactants, water, hydrocarbon oil and an alcohol as cosurfactant, 12 types of cleaning agents were prepared, and their physical properties such as surface tension, viscosity, electroconductivity and phase stability were measured. As the formulated cleaning agents have low surface tensions(30.5-31.1 dyne/cm) and low viscosities (1.6-7.2 c.p.), they are satisfied with the general physical properties of water-in-oil(W/O) microemulsions for their industrial use. They showed a tendency that their temperature range for stable one-phase microemulsion decreased in accordance with the increase of alcohol/surfactant(A/S) ratio in the formulations. However, the temperature range of one-phase microemulsion was much more affected by hydrophilic lipophillic balance(HLB) value of the nonionic surfactant which increased its temperature range and it increased in accordance with the higher HLB value in the formulations. And the maximum content of water which can keep stable one-phase W/O microemulsion was measured at each sample. In addition, their temperature range for stable one-phase microemulsion was also measured. It was confirmed that the selection of surfactant type was very important for formulating a cleaning agent, since the W/O microemulsion system with the nonionic surfactant of the lower HLB value showed better cleaning efficacy that of the higher HLB value for abietic acid as a soil, which was used for preparing a rosin-type flux. In the formulated cleaning agents with the increase of A/S ratio in the formulations, however, there was no significant difference in cleaning efficacy. It was investigated that the differences of their cleaning efficacy was affected by the change of the condition of temperature and sonicating frequency as important factors in the industrial cleaning. That is, the higher, their cleaning temperature and the lower, their sonicating frequency, the more increased, their cleaning efficacy. Furthermore, using optical instruments like UV/Visable Spectrophotometer and FT-IR Spectrometer, their cleaning efficacy for abietic acid was measured. The removal of soil from the contaminated rinse water was measured by gravity separation method in the rinse bath. As a result, the cleaning agent system having the nonionic surfactant of HLB value 6.4 showed over 85% water-oil separation efficacy at over $25^{\circ}C$. Therefore, it was demonstrated in this work that the formulating cleaning agents were very effective for cleaning and economical in the possible introduction of water recycling system.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.18 no.4
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• pp.472-479
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• 2011

Purpose: The purpose of this study was to develop guidelines for cleaning of enteral nutrition bags by comparing the level of equipment contamination according to cleaning and disinfection methods. Method: This study was a true-experimental study, with 60 cases in total. Twenty cases each were randomly assigned to tepid water, detergent and brush, and disinfectant groups. The period of the experiment was March to April 2010, and enteral nutrition was given for 1 houre, 3 times a day at 7AM, noon, and 7PM for seven days. Enteral nutrition bags were cleaned after each feeding according to assigned cleaning and disinfection method followed by microbial cultures on 4th and 8th day before the 7AM feeding. Results: After 3 days of feeding and cleaning, the level of contamination of bags was not significantly different among the three groups. After seven days, the level of contamination was significantly lower when bags were cleaned with detergent and brush or with disinfectant compared to cleaning with tepid water. Conclusion: In cases where enteral nutrition bags are reused for example, in home care settings, studying findings indicate that cleaning bags using detergent and brush or disinfectant is an effective way to prevent contamination of bags.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.7
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• pp.987-997
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• 1999

The purpose of this study was finding out the appropriate cleaning method for buried fabrics from old tombs focusing on the conservation of textiles. Cleaning effects and physical properties change depending on cleaning method have been analysed, The following results were obtained from this study : 1. Wet cleaning showed better effect on the cleaning of fabrics compared to solvent cleaning which meant more water-soluble soils existed than oily soils. 2. All the cleaning methods used did not cause any distorsion or shrinkage to the fabrics because fabrics had been stabilized for a long time 3. Addition of detergent to cleaning system decreased the friction of fiber during cleaning rocess so that the damage of fabrics could be minimized., 4. Ironing is an undesirable process because heat remarkably weakened fibers.

• Agribusiness and Information Management
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• v.9 no.1
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• pp.18-22
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• 2017

It takes lots of time and labor if a worker have to measure the water quality at a certain but designated time every day in an un-automated aqua farm. In addition, if the equipment is soaked in the sea water consistently, it will be contaminated by diverse floating matters and barnacles, and it often becomes mal-functional within 2~3 months. Therefore, we need to develop a system with which the sensed data could be checked in real time and operated automatically, while preventing the contamination of the sensor, a crucial component for water quality measuring equipment, as much as possible, and increasing the replacement cycle. We have developed a non-cleaning water quality measuring equipment and its software which are used in the fishery household of offshore aqua farms. By providing the workers with a mobile application which has a function of monitoring the water quality in real time, they can check the situation directly without going to the fishery household.