• Particle and aerosol research
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• v.19 no.3
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• pp.63-76
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• 2023

An electrostatic precipitator (ESP) has a low pressure drop and a high collection efficiency but its collection efficiency can be reduced due to dust accumulation on the collection plates during long-term operations. In order to maintain the initial dust collection efficiency, it is necessary to periodically clean the collection plates. The common cleaning methods are using physical impacts or water sprays. These cleaning methods can lead to damage to the collection plate or generate wastewater. Herein, we implemented an electrodynamic screen (EDS) for ESP cleaning and evaluated its surface cleaning performance of particles. The EDS is an electrostatic system that can electrostatically repel particles on surfaces, allowing it to clean the ESP without causing damage and wastewater generation. Our evaluation included the analysis of the effects of AC voltage characteristics, electrode configuration and environmental conditions on the cleaning performance of the EDS with the aim of achieving effective surface cleaning. It has been demonstrated that activating the EDS cleans up to 65% of the particles on the surface, which indicates about 94% of our target cleaning zone.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.381-392
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• 2020

The necessity and the importance of the remanufacturing are increasing day by day along with environmental problems. Many studies are being conducted on remanufacturing, but the research for cleaning is much lacking. This study aims to evaluate the effective cleaning method for remanufacturing of start motors, one of the automobile parts. The cleaning process consists of oil stain removal, drying and rust removal processes. In this study, the two processes were conducted except for the drying process which has little influence on cleaning. The methodology for cleaning agent selection, degreasing and rust removal process was presented. For each methodology, five analysis factors were calculated by two-way comparison according to the process, and the values were evaluated quantitatively by substituting them into the evaluation table. In the selection of cleaning agent, neutral system, ultrasonic cleaning in degreasing, and grinding in rust removal were selected as the best cleaning methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.631-632
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• 2008

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.2
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• pp.101-106
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• 2013

Purpose: This research was to evaluate the sterilization effectiveness for bacterial contamination by general cleaning method of glasses for vision correction. Methods: From 82 eyeglass wearers the number of bacteria before and after cleaning was counted to check the status of the eradication. Results: The results after ultrasonic cleaning by using the tap water did not showed change of bacterial species. Ultrasonic cleaning using the 70% rubbing alcohol showed cleaning of 46.2% of bacteria. Ultrasonic cleaning using the 70% rubbing alcohol after brushing with general detergent showed clearing of 85.7% of bacteria. Conclusions: When glasses were brushed with a detergent, opportunities infectious bacteria in glasses for vision correction were removed effectively. These results can be suggested as a guideline for management of clean glasses.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.269-274
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• 2004

As next generation display, TFT LCD gets into the spotlight, and the bigger glass size is required. Currently, its display size is 1500 mm by 1870 mm at the six generation comparing with 300mm by 400 mm at the first one and the size is increasing continuously, which cause the difficulties to apply the cleaning operation including the general brush cleaning. In this study, water-jet cleaning operation has been introduced, which spent the less water them other cleaning methods. Throughout the experiment, is has been found the possible damage of the declined cell and the variation of the tilt bias angle depending upon the increasing time. In addition, the simulation predicts the glass bending of the display.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.174-184
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• 2020

Objectives: The purpose of this study was to improve the working environment by identifying the work satisfaction of the cleaning workers of the aircraft and measuring and assessing the harmful factors of the cleaning process. Methods: We asked 23 cleaning companies for questionnaires and got 100 answers from 5 companies. The A-E Airline health manager has been contacted to establish a site survey schedule. The in-flight and lounge were measured using direct reading equipment. The harmful factor to be measured are noise, dust, temperature, volatile organic compound, total airborne bacteria, and total airborne bacteria. Results: Uncomfortable positions when replacing blanket, cleaning the table, and cleaning the floor have been identified as factor that reduce work satisfaction. Noise when replacing newspapers and cleaning toilets has been identified as a factor that lowers work satisfaction. Temperature and humidity were found to reduce work satisfaction during in-flight disinfection. Measurements of aircraft cabin and lounge with direct read equipment have shown that none of the items exceed the exposure criteria. Conclusions: As a result of measuring direct-reading equipment, no items exceeded the exposure criteria for each harmful factor. A clear survey of the working environment is required based on the results, and additional research is needed using personal sample measurement.

• Safety and Health at Work
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• v.6 no.4
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• pp.345-352
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• 2015

Background: Goal-oriented communication of risk of hazards is necessary in order to reduce risk of workers' exposure to chemicals. Adequate training of workers and enterprise priority setting are essential elements. Cleaning enterprises have many challenges and the existing paradigms influence the risk levels of these enterprises. Methods: Information on organization and enterprises' prioritization in training programs was gathered from cleaning enterprises. A measure of enterprises' conceptual level of importance of chemical health hazards and a model for working out the risk index (RI) indicating enterprises' conceptual risk level was established and used to categorize the enterprises. Results: In 72.3% of cases, training takes place concurrently with task performances and in 67.4% experienced workers conduct the trainings. There is disparity between employers' opinion on competence level of the workers and reality. Lower conceptual level of importance was observed for cleaning enterprises of different sizes compared with regional safety delegates and occupational hygienists. Risk index values show no difference in risk level between small and large enterprises. Conclusion: Training of cleaning workers lacks the prerequisite for suitability and effectiveness to counter risks of chemical health hazards. There is dereliction of duty by management in the sector resulting in a lack of competence among the cleaning workers. Instituting acceptable easily attainable safety competence level for cleaners will conduce to risk reduction, and enforcement of attainment of the competence level would be a positive step.

• Journal of Applied Reliability
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• v.18 no.1
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• pp.66-71
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• 2018

Purpose: Performance recovered from SCR through cleaning was studied, measuring differential pressure, NOx reduction efficiency, fuel consumption and engine power before and after cleaning. Ideal cleaning intervals are proposed based on SCR mileage and differential pressure. SCR endurance and reliability improvements through cleaning were studied through physicochemical testing of SCR durability at 43,000km 50,000km, and 110,000km respectively. Methods: Engine power, fuel consumption and exhaust gas were measured using engine full load tests and ND-13 MODE by installing the SCR before cleaned at total engine mileages of 400,000 km, 300,000km and 200,000km. The same tests were performed after cleaning the SCR catalytic converter. Endurance and reliability of the SCR cleaning was studied through the same test by SCR catalyst after each 43,000km 50,000km, 110,000km, durability test on SCR cleaning. Conclusion: We confirmed the low-performance of the SCR due to clogging is restored by SCR cleaning technology. The NOx reduction efficiency was restored to 82%, 86% and 88% from 69%, 72% and 79%. As well as the NOx reduction efficiency, it was confirmed that the engine power, fuel consumption and back pressure was restored to fresh SCR levels. As a result of the durability and reliability achieved through SCR cleaning, we confined the appearance and reduction efficiency through visual inspection and ND-13 MODE are similar to new SCR catalysts. Finally, it was judged that there was no change in performance even when driving the SCR without cleaning throughout the 100,000 km mileage warranty.

• Clean Technology
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• v.18 no.3
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• pp.287-294
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• 2012

In this study, performances of two cleaning methods were analyzed and a cleaning system was designed to develop a cleaning process of electronic components to remanufacture old laser copy machine. First, plasma cleaning as a dry cleaning method was executed to test cleaning ability. In cleaning of printed circuit board (PCB) by plasma, some damages were found near the metal parts, and considering the productivity, this method was not adequate for the cleaning of electronic components. With 4 different cleaning agents, ultrasonic cleaning tests were executed to select an optimal cleaning agent, aqueous agents showed superior cleaning performance compared to semi-aqueous and non-aqueous agents. Cleaning with aqueous cleaning agent A and 28 kHz ultrasonic frequency can be completed in 30 sec to 1 min. Finally, an ultrasonic cleaning system was constructed based on the pre-test results. Optimal cleaning conditions of 40 kHz and $50^{\circ}C$ were found in the field test. The productivity and economic efficiency in remanufacturing of laser copy machine are expected to increase by adapting developed ultrasonic cleaning system.

• Journal of Conservation Science
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• v.27 no.3
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• pp.333-344
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• 2011

Cleaning of foreign matter and corrosion products on surface among conservation treatment of iron artifacts is an important part for looking up a original form. The sand blaster is the most popular equipment when it removes the foreign matter and corrosion products on iron artifacts surface. Current foreign matter and corrosion products equipment, which mostly uses, is sand blaster. Glass dust which sprayed from sand blaster is harmful and causing environmental pollution. In order to solve these problems, we investigated the $CO_2$ snow cleaning that use a eco-friendly equipment to apply for cleaning foreign matter and corrosion products on surface of iron artifacts. It examined by using sand blaster and $CO_2$ snow cleaning to aged steel coupon and iron artifacts. In case of aged steel coupon, the result showed that the sand blaster and $CO_2$ snow cleaning methods were similar to the degrees of cleaning foreign matter and corrosion products, through surface roughness, color measurement and SEM. $CO_2$ snow cleaning applied to aged steel coupons weren't worn out the surface in comparison with sand blaster by SEM. When applied to the iron artifacts, power nozzle of the $CO_2$ snow cleaning was an excellent cleaning effect that surface wern't worn out in comparison with sand blaster. And, it showed that internal structure change of metal was no found before and after cleaning by X-ray radiography. Consequently, we confirmed that cleaning of the sand blaster and power nozzle of $CO_2$ snow cleaning were similar to the effect. But, it's very careful to use this method because of high outlet pressure of power nozzle for applying to the iron artifacts. As a result of experiments, it could be found that the cleaning methods should be selected depending on internal state of the artifacts.