• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.2
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• pp.183-193
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• 2013

The characteristics of dental treatment makes the dental staff frequently contact with patient directly. Also the daily use of high-handpieces, sharp instruments, and needles often causes bleeding on oral cavity. Therefore, the risk of cross transmission grows up. The pathogen from dental practice could spread on not only the practice itself but also the dental laboratory with contaminated impressions and prosthesis. Dental clinic staffs (dentists, dental hygienists and dental technicians) should recognize all the patients have a possibility of cross contamination, and try to prevent the transmission of infection by proper infection control. In this study, we review the articles about disinfection methods and chemical infection agents used for dental impressions, and try to figure out the suitable and effective infection control system of dental impressions.

• Journal of the Korean Geotechnical Society
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• v.36 no.8
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• pp.27-34
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• 2020

Strong alkaline waste water is generated in large quantities due to using Concrete, shotcrete and various compounds in tunnel construction sites. As the release of this alkaline waste water will contaminate the stream water, it has to be neutralized. Currently, this waste water is mainly neutralized by using sulfuric acid or hydrochloric acid, but the risks of corrosion and handling of facilities are inherent and the chemical control act requires strict management measures. Therefore, using CO₂ (carbon dioxide) as an alternative has been highlighted and various indoor experiment studies have been conducted to prove its potential. However, it is difficult to apply CO₂ to the site because it is still completely lacking in field application research and shows different characteristics from indoor experiments. In this study, the actual site applicability is verified through field testing.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.170-172
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• 2018

지구 온난화로 인해 여름철 북극해의 해빙이 점차 감소함에 따라서 북극항로를 이용한 선박의 화물운송이 점차 증가하고 있다. IMO에서는 극지해역운항선박의 안전성과 해양오염방지를 위하여 2014년에 Polar Code를 개정하였으며, 2017년 1월부터 SOLAS협약과 MARPOL73/78협약에 추가되어 시행되고 있다. 본 연구는 해양수산부 해양안전 및 해양교통시설기술개발 사업으로 1) Polar Code 강제화에 따라 '극지해역 운항선박용 항해안전지원시스템의 개발'의 필요성과 2) 북극항로에 대한 국적선의 안전 운항 확보를 위한 '북극권 국가와의 국제협력 및 공조체계 구축'과 '극지 구난, 구조 및 환경보호 관련 국내법 및 규정 제정'을 위한 기반 연구의 필요성에 의거하여 2014년 11월 10일에 시작되었으며 2018년 12월 31일에 종료될 예정이다. 연구내용은 1) 고정밀도 북극항로 빙상정보 수치예측 시스템 개발, 2) 북극항로 안전속도 예측, 평가, DB구축 및 항행 모델 개발, 3) 북극항로 안전운항을 위한 항해계획 기술 개발, 4) 북극항로 운항선박 건조 및 안전항해 가이드라인 개발이다. 본 논문에서는 개발 중인 KRISO Arctic safe Routing System (KARS)에 대한 소개와 활용 결과 및 향후 계획에 대해서 설명하고자 한다. 본 KARS는 향후 지속적인 수정보완 작업을 통해서 완성도를 높여갈 예정이며, 검증단계를 거쳐서 최적하고 안전한 항로와 운항 관련 정보를 선사와 해기사에게 제공함으로서 북극항로 중 단기 운항계획 수립과 안전 운항을 지원할 수 있을 것으로 기대된다.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.220-224
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• 2017

In this study, we investigated a new recycling method of phenol resin, which is widely used to make electric insulation boards and adhesives, into carbon particles by using supercritical fluids. Because phenol resin is insoluble and infusible, most of the phenol resin wastes are buried in the ground or incinerated, which leads to environmental pollution. Therefore, development of a new method to recycle phenol resin waste is an urgent issue. In this study, phenol resin waste was treated with four sub/supercritical solvents: ethanol, acetone, water, and methanol. For all the sub/supercritical solvents, the phenol resin wastes were broken down into carbon nano particles at much lower temperatures than that required in the existing carbon particle manufacturing processes. We investigated the difference of morphologies and physical properties of recycled carbon particles according to the use of various solvents. As a result, carbon nano particles with the same amorphous structure were obtained from phenol resin waste with the usage of various sub/supercritical solvents at much lower temperature.

• Resources Recycling
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• v.26 no.3
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• pp.3-16
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• 2017

Chemical catalyst products are applied to various fields such as petrochemical process, air pollution prevention facility and automobile exhaust gas purifier. The domestic and overseas chemical catalyst market is increasing every year, and the amount of waste catalyst generated thereby is also increasing. Most of the used chemical catalyst products, such as desulfurized waste catalysts and automobile waste catalysts containing valuable metals are important recyclable resources from a substitute resource point of view. The recycling processes for recovering valuable metals have been commercialized through some urban mining companies, and SCR denitration catalysts have been recycled through some remanufacturing companies. In this paper, the amount of domestic production and recycling of major catalyst products have thus been investigated and analyzed so as to be used as basic data for establishing industrial support policy for recycling of used chemical catalyst products. Also tasks for promoting the recycling of used chemical catalyst products are suggested.

• Journal of the Korea Institute of Building Construction
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• v.15 no.2
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• pp.153-160
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• 2015

The marble powder is a by-product that can be freely collected during the manufacturing process of marble, such as sawing, shaping, and polishing. Disposal of this waste powder is one of the environmental problems worldwide today. Therefore, this study investigated to solve this problem by consuming the waste marble powder in high fluidity concrete, as a pore filler. For this purpose, the waste marble powder was used as a binder replacing 5%, 10%, 15%, and 20% of cement in high fluidity concrete. After mixing, slump flow test, time-to-reach the slump flow of 500mm test, O-lot test and U-box test were conducted with fresh concrete. For the hardened concrete, compressive strength was determined at the age of 28 days. According to the test results, the workability of high fluidity concrete increased with the powder of 15% replacement, and the compressive strength of high fluidity concrete also increased with the same amount of powder.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.401-406
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• 2015

Getter is a class of materials used in absorbing gases such as hydrogen and moisture in microelectronics or semiconductor devices to operate properly. In this study, we developed a new device structure consisting of porous anodized alumina films on textured silicon wafer, which have cost efficiency in materials and processing aspects. Anodic aluminum oxide (AAO) with controlled pore sizes can be applied to a high-efficiency moisture absorber due to the high surface area and OH- saturated surface property. The moisture sorption capacity was 2.02% (RH=35%), obtained by analyzing isothermal adsorption/desorption curve.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1779-1784
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• 2010

Net washing in a fishery involves considerable labor and is a time-consuming process; it also causes severe environmental pollution. In this study, we developed a net hauler for washing fishing nets. This hauler can be used to simultaneously haul and wash the net. We devised the revolver structure of the net hauler in order to resolve the net slip problem. The net hauler can be used by itself for washing small-sized nets, or it can be used in an auxiliary washing step in case of a large-sized net. Further, the component installed in the net hauler for unraveling the net improves the net washing performance of an automatic net washer. During the experiments conducted using the prototypes of the new net hauler, the net did not slip and the desired washing performance could be achieved.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.146-155
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• 1983

Fundamental study was carried out to elucidate the mechanisms of biological degradation of dyestuff in environments. A few bacterial strains which were capable of degrading amarnath were obtained from soil through an extensive screening program and identified by microbiolological properties. Conditions for bacterial growth and amaranth degradation were characterized and optimized, and the degradation products were identified. The results were as follows. 1. The most active strain A12-1 to be capable of degradation of amaranth was identified as Pseudomonas sp. 2. Optimal conditions for growth of the strain A12-1 were:$35^{\circ}C$ and pH 7.5, and growth was markedly increaesd by aeration. 3. Degradation of amaranth by the strain was accessed under similiar conditions for growth, however significantly inhibited when the culture was aerated. 4. Both bacterial growth and amaranth degradation were gradually decreased with increased concentration of amaranth in the culture. 5. Reaction of the crude enzyme from the strain A12-1 was optimal at $35^{\circ}C$ and pH 7.5 for degrading amaranth. 6. Sodium naphthionate and R-amino salt were found to be the products of amaranth degradation by the strain A12-1.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.235-243
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• 2011

Gyeongin Ara Waterway will be open on Oct., 2011, Which is the first inland artificial waterway constructed in Korea. There have been arguments about the environmental issues and economic effectiveness, however, it's now time to focus on the safety of navigation at the waterway to protect human life, property and environment. Therefore this paper aims at examining the establishment of the rule of safe navigation and management for the safe and effective management of the waterway and tries to draft the rules based on these examinations. The draft rule consists of 7 chapters, which are general rules, general rules on navigation, specific rules on navigation, general restrictions, emergency response, restrictions on navigation and penalties in consideration of the characteristic of Gyeongin Ara Waterway and regulations on navigation in major canals in the world.