• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.142-143
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• 2002

내륙 및 임해공업단지와 관련하여 수질오염을 거론할 때 특정 공정과 연관된 오염원을 주로 지목한다. 그러나 대부분의 공업제품 생산공정에서는 금속과 기계장치의 기름과 윤활유 세척에 TCE(trichloroethylene)와 PCE(perchloroethylene)가 함유된 세척제를 많이 사용하고 있다. 우리나라 임해공업단지 배수로와 연안해역에서는 우려할만한 TCE와 PCE가 검출되고 있다. (중략)

• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.42-43
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• 1995

현재 에탄올 분리공정에서 사용하고 있는 투과증발분리 공정은 7-10%의 fermentation broths로 부터 나온 feed를 재래식 증류법으로 약 95%의 등비 혼합물까지 농축한 후 가교 polyvinylalcohol(PVA)를 사용하여 투과증발을 행하여 99.5%의 에탄올을 제조하고 있다. 현재 세계적으로 가장 많이 쓰이고 있느느 투과증발막으로는 독일의 GFT사로부터 개발되었고 PVA막을 PAN 부직포에 coating하여 제조하고 plate and frame type의 module을 써서 pervatporation unit를 생산하고 있다. 이러한 PVA 막보다 우수하며 여러 유기물 범위에서 사용가능한 막을 제조하기 위하여 많은 노력이 이루어지고 있다. 이같은 개량된 투과증발막을 제조하기 위하여 본 연구에서는 천연에 풍부히 존재하는 천연고분자인 키토산을 이용하였다.

• Resources Recycling
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• v.13 no.4
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• pp.17-22
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• 2004

This study was focused on the treatment of thickened sewage sludge. General bacteria and E. coli were disinfected over 99％ and organic compounds were decomposed after irradiation. It was suggested that this process can be an alternative for digestion Process. The moisture content in sludge was decreased over 10％ (w/w) and the coagulation of sludge particles was enhanced by irradiation at the dose of 15 kGy and addition of sea waste resource (star-fish) as a dewatering aid.

• KSBB Journal
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• v.20 no.3
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• pp.142-148
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• 2005

Succinic acid is an important material in industries producing biodegradable polymers, food and pharmaceutical products, and green solvents. Furthermore, succinate fermentation is a novel process due to the fixation of $CO_2$ into succinate during fermentation. However, the impurities in fermentation broth make the separation process of succinic acid be difficult. Reactive extraction has been proposed to be an effective primary separation step of succinic acid from dilute fermentation broth. This article presents the principles of reactive extraction along with the characteristics of tertiary amino extractants. A brief overview on the current research on reactive extraction of succinic acid is presented. Finally, for the succinic acid separation, reactive extraction as a primary step is suggested in the whole downstream process for succinic acid from fermentation broth.

• Journal of Korea Water Resources Association
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• v.34 no.3
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• pp.231-240
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• 2001

The problem of the flocculation basin was induced by installing the pilot plant using tracer test at Yang-Duck water treatment plant in Pohang cite. The flocculation basin model downscaled as 1/20 was made of acryl and evaluated hydraulically by transforming the section of the effluent in the flocculation basin. The optimum section of the effluent was suggested and applied to the plant. The efficiency of the flocculation basin according to improvement was evaluated by the particle counter which can count the number of particles each size fraction. The results of this study are as follows : First, it was desirable to make the retention time as short as possible because the flow and the index value were similar regardless of the retention time. Second, after the modification in Yang-Duck water treatment plant, the problem of destruction of floe was improved and the plant was operated satisfactorily. The hydraulic experiment with tracer test can be applied to the performance evaluation as well as improvement of facility in unit process of existing water treatment plant. Additionally, it can be used to find a design factor in the new water treatment plant.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.775-780
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• 2008

Sludge conditioning is widely used to improve aggregation and dewaterability of waste sludge in sludge treatment processes. The study aims to examine quantitative correlations between coagulant dosage and sludge cake dewaterability using three kinds of coagulants, such as an aluminum sulfate, a ferric chloride, and a poly aluminum chloride(PAC). When an aluminum sulfate, a ferric chloride, and a PAC were injected with 0.79$\sim$1.19 mmol/g, 0.61$\sim$1.25 mmol/g TSS, and 0.21$\sim$0.39 mmol/g TSS, respectively, specific resistances to filtration of the sludge were decreased at 95.0% or more. This study shows that the correlation between coagulant dosage per g sludge(D) and normalized specific resistance to filtration(R) could be expressed by the exponential functions.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.53-64
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• 2019

The term 're-use' here signifies the re-use of end-of-life products without changing their form after they have been thoroughly inspected and cleaned. In the re-use network model, the distributor determines the product order quantity on the network through which new products are received from the suppliers or products are supplied to the customers through re-use of the recovered products. In this paper, we propose a reusable network model for reusable products that considers the total logistics cost from the forward logistics to the reverse logistics. We also propose a reusable network model that considers the processing and disposal costs for reuse in an optimal inventory management environment. The authors employe Genetic Algorithm (GA), which is one of the optimization techniques, to verify the validity of the proposed model. And in order to investigate the effect of the parameters on the solution, the priority-based GA (priGA) under three different parameters and the modified Hybrid GA (mhGA), in which parameters are adjusted for each generation, were applied to four examples with varying sizes in the simulation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.3
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• pp.167-174
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• 2009

A comprehensive analysis has been conducted on the purity of the uranium product generated from a pyroprocessing of EBR-II spent fuel. The analysis results were compared to the low-level waste criteria for both ROK and USA under a collaborative program between INL and KAERI. It is found that the US LLW definition does not include the activity from any U isotopes, but the Korean one does. The analysis results show that Pu-239 is the only alpha emitting isotope other than U isotopes that exceed the limit in the EBR-II U product. Pu contamination of the product seems to be drastically reduced in a preliminary test of the modified cathode process, and the further development of the proposed technology may be possible to meet the US LLW criteria.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.99-99
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• 2016

최근 공구산업은 산업 발전으로 공구의 사용 환경이 가혹화 되고, 첨단산업용 특수합금들이 발달하면서 이를 가공할 수 있는 새로운 절삭공구소재들이 개발되어지고 있다. 또한 고성능 절삭공구는 공구소재보다 코팅개발이 상대적으로 더욱 효과적이기 때문에 코팅 기술 개발이 활발히 진행되고 있다. 최근 일본에서는 새로운 코팅층 물질 개발보다는 기존의 코팅물질을 조합하거나 개량하여 성능을 향상시키는 추세이며, 이는 현재 공구산업의 효율적인 개발방향을 제시하고 있다. 기존의 빗각 증착은 기판의 각도를 변경하여 증기가 기판에 비스듬하게 입사하도록 조절하여 코팅하는 기술로 박막의 조직을 다양하게 제어하는 것이 가능하며, 구조 제어를 통한 완전화 박막을 이용한 one-batch 다기능 구현을 위하여 많은 연구가 진행되고 있다. 가공이 까다로운 소재를 가공하기 위한 공구에 적용하기 위해서 Al의 함량이 높은 AlTiN 소재가 개발되어 적용되고 있으며, 이 소재는 공구의 수명향상을 위한 표면처리 소재로 각광을 받고 있다. 본 연구에서는 음극아크 증착 시 거대입자가 박막에 증착되어 결함을 만들기 때문에 그 밀도를 낮추기 위해서 음극 아크 증착을 이용하여 공정 변화에 따른 AlTiN 박막의 표면형상을 관찰하고 특성을 평가하였다. 또한 빗각 증착을 적용하여 제작한 AlTiN 박막의 특성을 평가하였다. 고 함량의 AlTi합금 타겟을 음극 아크 소스에 장착하여 AlTiN 박막을 코팅하였다. 시편은 스테인리스강판(SUS304)과 초경(tungsten carbide; WC)을 사용하였다. 음극 아크 소스에 인가되는 전류가 낮을수록 AlTiN 박막 표면에 거대입자의 밀도가 낮아졌으며, 기판 전압과 공정압력이 높을수록 AlTiN 박막의 표면에 존재하는 거대입자의 밀도가 낮아지는 경향을 보였다. 이를 통하여 거대입자밀도를 낮추는 기초공정을 도출하였다. AlTiN 박막 제작 시 빗각을 적용한 결과 $60^{\circ}$의 빗각을 적용한 다층 박막에서 상대적으로 가장 높은 경도 값을 보였다. 본 연구를 통해 음극 아크 증착을 이용하여 거대입자의 밀도가 낮은 박막을 제작할 수 있는 공정을 도출하였고, 빗각증착을 적용하면 경도가 향상되는 결과를 확인하였다.

• Journal of Astronomy and Space Sciences
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• v.21 no.2
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• pp.141-152
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• 2004

Optics fabrication process for precision space optical parts includes bound abrasive grinding, loose abrasive lapping and polishing. The traditional bound abrasive grinding with bronze bond cupped diamond wheel leaves the machine marks of about $20{mu}m$ rms in height and the subsurface damage of about 1 ${mu}m$ rms in height to be removed by subsequent loose abrasive lapping. We explored an efficient quantitative control of precision CNC grinding. The machining parameters such as grain size, work-piece rotation speed and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis. The effectiveness of such grinding prediction models was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment achieved the predictability down to ${pm}20$ nm in height and the surface roughness down to 36 nm in height. This study contributed to improvement of the process efficiency reaching directly the polishing and figuring process without the need for the loose abrasive lapping stage.