• Korean Journal of Computational Design and Engineering
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• v.16 no.1
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• pp.61-72
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• 2011

As the customer's needs for diverse colors, the process of bus painting shop is becoming more and more complex. In particular, frequent changes of paint colors in each spray process require the cleaning of the painting nozzles and setting them up for the new paints, which results in increased time and cost and reduced production. This also increases environmental influences. This paper proposes, as a solution to this issue, the use of color selection field (CSF). CSF is physically a system of conveyors that are used to rearrange objects in a flow line. CSF is proposed, in this paper, to be introduced right before the spray process so that buses are better grouped according to their desired colors. Various parameters of the CSF, such as the number of conveyors and algorithms to determine the rearranged sequence of buses, have been determined by running simulations using the digital manufacturing technology, and investigating the simulation results. As an outcome of the proposed solution, the CSF system is expected to reduce approximately 30% of the nozzle cleaning cost for a Korean motor company case, which will not only benefit the company economically, but will also benefit the environment.

• Journal of Adhesion and Interface
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• v.14 no.3
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• pp.111-116
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• 2013

In this study, we studied surface and adhesion properties with plasma treatment for substitution of buffing and solvent-cleaning in footwear adhesion process. The distance between nozzle and rubber parts was decreased with decreasing the contact angle. And when a speed of plasma treatment increased, the contact angle increased. The result of surface roughness, Ra and Rz increased in 20% and 16% after the plasma treatment. The distance of between nozzle and rubber parts was decreased with decreasing the peel strength. And the speed of plasma treatment was increased with decreasing the peel strength.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.520-528
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• 2012

Objective: This study was performed to assess bacterial distribution concerned in sanitation management of public lavatory in Seoul. Methods: In this research, bacteriological investigation on public lavatory was accomplished for bidet water, bidet nozzle, washbowl and lavatory stool in the 50 public facilities such as public institutions, subway stations, cinema, department stores, large-scale buildings and hospitals amount to 374 specimens. Results: The geometric mean of colony forming unit(CFU) in total aerobic colony count were analyzed as follows; $5.2{\times}10^2/100cm^2$ on lavatory stool, $7.2{\times}10^3/ea$ on bidet nozzle, $7.8{\times}10^3/ea$ on center ring of washbowl, $1.4{\times}10/mL$ in bidet water (ml) and 7.0/ea on doorknob. Opportunistically pathogenic germs such as Staphylococcus aureus, Escherichia coli, Enterobacter cloacae, Pseudomonas aeruginosa were isolated in 3.7%, 5.9%, 3.2% and 1.9% of total specimens, respectively. Conclusion: The result of this study shows that there were some facilities where the pathogenic germs were detected to may cause urological infection. And the CFU of general bacteria as the representative indicator of disinfection and lavatory cleaning were high enough to imply the improvement of sanitation management of public lavatories should be contrived.

• Particle and aerosol research
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• v.15 no.1
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• pp.1-13
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• 2019

Current desulfurization and denitrification technologies have reached a considerable level in terms of reduction efficiency. However, when compared with the simultaneous reduction technology, the individual reduction technologies have issues such as economic disadvantages due to the difficulty to scale-up apparatus, secondary pollution from wastewater/waste during the treatment process, requirement of large facilities for post-treatment, and increased installation costs. Therefore, it is necessary to enable practical application of simultaneous SOx and NOx treatment technologies to remove two or more contaminants in one process. The present study analyzes a technology capable of maintaining simultaneous treatment of SOx and NOx even at low temperatures due to the electrochemically generated strong oxidation of the wet-pulse complex system. This system also reduces unreacted residual gas and secondary products through the wet scrubbing process. It addresses common problems of the existing fuel gas treatment methods such as SDR, SCR, and activated carbon adsorption (i.e., low treatment efficiency, expensive maintenance cost, large installation area, and energy loss). Experiments were performed with varying variables such as pulse voltage, reaction temperature, chemicals and additives ratios, liquid/gas ratio, structure of the aeration cleaning nozzle, and gas inlet concentration. The performance of individual and complex processes using the wet-pulse discharge reaction were analyzed and compared.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.506-512
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• 2018

The fine dust generated in the home and restaurant business occupies a low ratio of about 4% of the total fine dust emissions. However, at the foodservice business, the rate of change of the pollutant concentration is very high, so that the temporary fine dust concentration can be measured up to 60 times. The pollutants generated from non-industrial combustion plants consist of particulate fine dust and gaseous organic compounds. To remove these pollutants, cleaning dust collection system, which is an effective system for simultaneous removal of gaseous and particulate matter, is applied. This is a method of increasing the probability of diffusion capture of the Brownian motion by pressurized liquid injection method using the atomizing nozzle. The dust removal efficiency of the fine dust collecting system was analyzed by nozzle spraying air pressure condition and angle using the manufactured fine dust removing system. As a result, it was confirmed that the efficiency of removal of fine dust and gaseous organic compounds was more than 90%. The developed system is expected to be highly usable in the future because it can remove particulate dust from the existing plant hood system without any installation cost.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.1
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• pp.9-16
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• 2005

To evaluate parameters influencing on the dust removal of the High Temperature Filter(HTF) system, a computer simulation of fluid dynamics inside the system had been performed. The results showed that the optimum pulse jet periods were 50ms and 90ms for the 1000mm and 1500mm long filter elements respectively. Dust removal effect was very excellent under the pulse jet pressure of 3 bar. But the distance between the pulse jet nozzle and the venturi of a filter element had no meaningful effect on the performance with the variation from 5mm to 10mm. Compared to the dispersion mode of pulse jet, the collective mode of pulse jet flow was preferable in maintaining the pressure inside the system stable.

• Membrane Journal
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• v.23 no.2
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• pp.185-188
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• 2013

This study was carried out for microfiltration tubular membrane module equipped with self-designed air injection nozzle in order to determine the permeate flux due to the effect of membrane fouling reduction. The 0.1 wt% yeast particle solution was used as a feed solution and permeation tests were performed for the cases with and without air injection. Permeation fluxes were measured and analyzed to examine the effect of membrane fouling reduction. While the permeation flux without air injection decreased continuously, that with air injection was improved more than 30 percent than that of no air injection case.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.94-94
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• 2018

무인자동차 및 전기자동차 등 전장부품 및 메인보드에서의 오염 방지와 전자파에 의한 신호 간섭 현상에 따른 기기의 오작동을 방지하고자 MWCNT의 clustering 및 tangling현상을 활용하여 self cleaning 기능을 갖는 super hydrophobic 표면과 high aspect ratio에 의한 percolation 현상을 활용하여 전자파 차폐를 위한 낮은 표면저항을 만족하는 복합 재료로 구성된 코팅에 관하여 연구하였다. 이를 위해 isopropyl alcohol(IPA)을 용매로 산처리 한 MWCNT와 무기바인더, 불소계 실란을 첨가하여 초음파 분산을 함으로써 코팅액을 제조하였다. 이를 full cone nozzle type, 흡상식 스프레이 조건으로 알루미늄 시편위에 스프레이 코팅 후 열경화 하여 접촉각측정기로 측정 결과 $160^{\circ}$이상의 초발수 표면과 Low Resistivity Meter로 표면저항을 측정한 결과 $10^3{\Omega}/cm^2$ 이하의 낮은 코팅막을 구현하였으며 내구성 실험을 위한 항온항습 장비로 $80^{\circ}C$의 내열테스트 및 80%와 $80^{\circ}C$조건하에서의 내습테스트 결과 표면에 이상 없음을 확인하였고 열전도율 측정을 위해 밀도 측정 결과 $2.68g/cm^3$, 비열 측정 결과 $0.85J/g^{\circ}C$가 열확산율 측정결과 $88.64mm^2/s$가 측정 되었으며 밀도, 비열, 열확산율을 곱한 값인 $201.9W/m{\cdot}K$의 열전도를 갖는 코팅막을 구현하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.157-165
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• 2017

The high-pressure resin transfer molding (HP-RTM) technology has been commercialized for fast production of fiber reinforced composite materials. The high-pressure mixing head was one of the most core component of the HP-RTM process. In this study, a mixing head was systematically designed, manufactured and evaluated. This mixing head was composed of a nozzle, a mixing chamber, a cleaning piston part, and an internal mold release part. In actual, a straight-type structure was newly designed instead of the conventional L-type structure for improving the maximum mixing pressure and mixing ratio precision. The performance of mixing head was showed maximum mixing pressure of 15.22MPa and mixing ratio precision of 0.12%. CFRP molding experiments were successfully obtained a 6~11 laminating carbon sheet using HP-RTM presses and specimen molds.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.725-736
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• 2016

There is a growing concern on the improvement of water distribution pipeline for multi-regional water supply system in Korea along with its aging infrastructure. Rehabilitation of large diameter pipeline is more efficient in cost and time compared to replacement with trenching. The procedure for rehabilitation are diagnosis, cleaning, spraying coating material, and final inspection. The internal state of pipeline was carefully diagnosed and got C grade, which required rehabilitation. We found that 17,274,787,000 Korean won could be saved after pipe surface coating because of increased C coefficient of Hazen-Williams equation. Optimal coating material was D polyurea. We also found optimal distance between spraying nozzle and pipe wall to be 70 - 80 cm, which were critical factors for coating quality. This study also illustrated the time for spray drying to be more than 30 min. These results could be used in the quality control process during rehabilitation of aged pipelines.