• 한국정밀공학회지
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• 제30권4호
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• pp.390-396
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• 2013

Due to the development of technology, there is a considerable increase in the number of skyscrapers in the world. Accordingly, there are rapid growing requests about maintenances such as cleaning, painting, and inspection. However, it is extremely dangerous working the walls of buildings, and crashes from buildings have accounted for large proportion of constructional accidents. Especially, as the number of buildings with irregular shapes increases, the accident rate during the maintenance work increases each year, and most of the accidents lead to death. An alternative solution must be developed with the commercialization of automatic systems. In this research, a fundamental research has been conducted for drafting and commercializing an automation tool that is carried in the built-in guide system, which can perform cleaning.

• 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.

• 한국표면공학회지
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• 제45권4호
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• pp.143-150
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• 2012

Laser cleaning have been found to be a useful cleaning tool to remove contaminants without inducing damage to the substrate and making secondary pollutant. In this study, the effect of Nd:YAG laser cleaning system, emitting at 1064 nm and 532 nm, on acrylic resin applied onto copper coupons and pieces of bronze was investigated. The samples after laser cleaning tests were examined using microscopy, FT-IR, SEM-EDS. As a result, the acrylic resin could be removed from most of the samples at low laser energy density. Laser wavelength 532 nm was more effective than 1064 nm because of using lower laser energy density, which could reduce heat damage to substrates. Although the acrylic resin was easily removed, it revealed melted surfaces and removed bronze patina which must remain. The problems should be solved by future studies using different laser system or laser wavelengths.

• 대한기계학회논문집A
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• 제37권6호
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• pp.815-820
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• 2013

고층 건물 외벽의 유지보수작업은 매우 위험하며 건설부분 산업재해에서 추락이 상당부분을 차지하고 있다. 국내에서 수행되는 고층 건물 외벽의 유지보수작업은 재래식 로프와 곤돌라를 이용한 방법이 대부분이며, 이는 잦은 안전사고의 발생과 생산성 저하의 원인이 된다. 특히 비정형 형태의 고층 건물이 증가함에 따라 외벽 유지보수작업의 안전사고율이 매년 증가하고 있으며 사고의 상당부분이 사망으로 이어지고 있다. 이와 같은 산업재해와 숙련공의 노령화는 향후 건설인력수급의 불균형을 초래할 것으로 예상된다. 이에 대한 해결책으로 건설 산업의 자동화가 필수적이다. 고층 건물 외벽 유지보수의 자동화는 산업재해의 감소와 비용의 절감을 기대할 수 있다. 본 연구에서는 빌트-인 가이드 방식의 로봇시스템에 탑재되어 청소를 수행할 수 있는 자동화 기구를 기안하고 상용화를 위한 연구를 수행하였다.

• 상하수도학회지
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• 제25권3호
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• pp.285-291
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• 2011

Membrane fouling is an unavoidable phenomenon and major obstacle in the economic and efficient operation under sea water reverse osmosis (SWRO). When fouling occurs on the membrane surface, the permeate quantity and quality decrease, the trans-membrane pressure (TMP) and operation costs increase, and the membrane may be damaged. Therefore, chemical cleaning process is important to prevent permeate flow from decreasing in RO membrane filtration process. This study focused on proper chemical cleaning condition for Shuaibah RO plant in Saudi Arabia. Several chemical agents were used for chemical cleaning at different contact time and concentrations of chemicals. Also autopsy analysis was performed using LOI, FT-IR, FEEM, SEM and EDX for assessment of fouling. Specially, FEEM analysis method was thought as analyzing and evaluating tool available for selection of the first applied chemical cleaning dose to predict potential organic fouling. Also, cleaning time should be considered by the condition of RO membrane process since the cleaning time depends on the membrane fouling rate. If the fouling exceeds chemical cleaning guideline, to perfectly remove the fouling, certainly, the chemical cleaning is increased with membrane fouling rate influenced by raw water properties, pre-treatment condition and the point of the chemical cleaning operation time. Also choice of cleaning chemicals applied firstly is important.

• 로봇학회논문지
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• 제4권1호
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• pp.74-80
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• 2009

This paper presents a remote monitoring and simulation system for a building cleaning mobile robot. It provides a tool of convenient 3D graphical map construction including network camera image viewer and status information of the robot. The 3D map is reconstructed from existing 2D building CAD data with DXF format using OpenGL graphic API. Through this system, it is possible to monitor and control the cleaning mobile robot from remote place. A practical experiment is performed to show the reliability and convenience of the monitoring system. The proposed system is expected to give efficient way of control and monitoring to building cleaning mobile robot.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1769-1770
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• 2007

To prevent an insulator failure, an automatic cleaning robot was developed for suspension insulator strings. The robot autonomously moves along the insulator string using the clamps installed on its two moving frames, and adopts a dry cleaning method using rotating brushes and a circular motion guide. In addition, a mechanized brush bristles and a voltage-balancing contactor are devised to increase cleaning efficiency and to prevent arc generation under live-line conditions, respectively. Moreover, a manual tool for its installation and removal is presented. We confirmed its effectiveness through experiments.

• 동력기계공학회지
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• 제18권1호
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• pp.63-68
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• 2014

The numerical analysis of fluid flow in the tube cleaning system is examined. The working flow used in this study is seawater, and the temperature change is not considered as the temperature change of seawater in the tube cleaning system is negligible. Also, the analysis is performed under the assumption of steady state. The screens of complicated morphologies are simplified for the analysis, and only one fourth of the tube cleaning system is modeled as the system has a symmetrical shape. The velocity inlet boundary condition is employed for the seawater inlet, whereas the outflow boundary condition is employed for two seawater outlets. In applying the outflow boundary condition for the system with more than two outlets, the flow rate can be arbitrarily assigned. In the analysis, the finite-volume method based numerical analysis tool, the pressure based solver, the standard k-$\varepsilon$ model are utilized, and the under relaxation factor is modified appropriately. From the analysis, the distribution of velocity vectors, pressure and path lines are obtained, and the physical characteristics of fluid flow in the tube cleaning system is well-examined.

• 보존과학회지
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• 제19권
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• pp.19-30
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• 2006

저습지에서 출토된 상수리나무를 재료로 세척에 따른 수침고목재 내 이물질의 제거 효과와 물리 화학적 특성 변화를 파악하였던 바 얻어진 결과는 다음과 같다. 수침고목재에 나타나는 대부분의 무기성분은 수침고목재가 매몰된 토양환경의 성분과 거의 동일하였다. 보존처리 현장에서 적용하고 있는 세척방법 즉, 도구법, 탈기법, EDTA법 및 초음파세척법을 적용하여 독립적 혹은 연속적 방법으로 수침고목재를 세척하였다. 독려세척의 경우 도구법에 의해 표면에 고착된 이물질이 효과적으로 제거되었고, EDTA 처리에 의해 표면 색상이 밝아졌다. 그러나 탈기법과 초음파에 의한 세척효과는 나타나지 않았다. 연속 세척의 경우 1단계 세척(도구법)은 독립세척과 동일한 효과를 얻었으며, 2단계 세척인 탈기법은 수침고목재 내에 있는 이물질을 제거하지 못했다. 탈기법이 무기물의 제거에는 적절하지 않았지만, 탈기 후 수침고목재가 균일화되어 치수안정제의 침투를 용이하게 하는 역할은 결코 무시할 수 없을 것으로 사료된다. 3단계 EDTA처리는 수침고목재 내의 철분(Fe)을 제거함으로써 수침고목재의 색상이 밝아지는 효과를 얻을 수 있었다. 4단계 세척은 3단계 세척시 목재 내에 잔류한 약품(Na)과 미세 이물질의 제거에 효과적이었다.

• 보존과학회지
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• 제10권1호
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• pp.10-20
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• 2001

1972년 이태리 베니스에서 J. F. Asmus에 의해 레이저를 이용한 석재 문화재 표면 세정의 가능성을 확인한 후, 많은 연구자들은 실험 및 검증의 과정을 통해 레이저 세정 기술이 기존의 기계적, 화학적 표면 세정 방법들과 비교해 여러 경우에 우수한 특성을 발휘한다는 사실을 인지하게 되었다. 이러한 인식의 확산으로 최근 유럽에서 레이저를 이용한 문화재 복원 연구가 활발히 진행되고 있으며, 석재, 유화, 스테인드글라스, 종이, 가죽 및 금속 문화재 복원에 있어 실질적 성공 사례들이 속속 보고되고 있다. 그러나 우리나라를 비롯한 동양에서는 이에 대한 연구가 미비한 실정이다. 이에 본 논문에서는 문화재 복원을 위한 레이저 세정 기술에 대한 전반적 이해를 돕고, 실제 응용 사례 연구를 통한 기술의 유용성을 설명해 보기로 하겠다. 논문의 내용은 크게 세 부분으로 나누어, 첫 번째로 레이저의 원리 및 레이저 빔의 특성에 관해 설명하였고, 두 번째로 레이저 세정 기술의 발전사 및 고유특성에 관해 서술하였으며, 마지막으로 문화재 유형별 세정 원리 및 다양한 실제 응용 사례를 제시하였다.