• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.106.2-106.2
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• 2010

동식물성 기름과 메탄올의 전이에스테르화 반응에 의해 생산되는 바이오디젤은 환경친화성과 지속가능성이 인정됨에 따라 그 생산량이 급격히 증가하고 있어 대두유, 유채유, 팜유 등의 원료유 부족과 가격 상승, 수급 불안정 등의 문제가 대두되고 있다. 이를 해결하기 위한 방안으로 유리지방산 함량이 높은 저가유지 자원(폐식용유, 폐돈지, 폐우지, soapstock, trapped grease)과 새로운 오일 작물을 이용한 생산 기술 연구가 활발히 진행되고 있다. 본 연구에서는 비활용 해외 열대작물 씨앗에서 착유한 식물성 오일을 정제하여 바이오디젤 원료유를 생산하는 과정에서 발생하는 폐기물(폐유, 폐수)의 경제적 처리 방안으로 유화유 제조 원료(벙커C유, 물)와 유화유 제조 첨가제(무기계, 유기계)로 활용 가능성을 검토하였다. 열대작물 오일의 물성 분석 결과 고형물, 수분, 인지질(phospholipid), 유리지방산(free fatty acid) 함량이 기존 원료유보다 매우 높게 나타났다. 인지질은 바이오디젤 제조 반응후 에스테르와 글리세린의 층분리를 방해하고 유리지방산은 염기촉매와 결합하여 지방산염을 생성해 생산 수율을 감소시킨다. 고형물과 수분 역시 촉매반응에 악영향을 가지나 여과와 감압증발에 의해 쉽게 제거가 가능하다. 유리지방산은 산촉매 에스테르화 반응에 의해 제거가 가능하다. 인지질은 탈검(degumming) 과정을 통해 제거하며 탈검은 수용성 탈검, 산 탈검, 세정 공정으로 구성된다. 착유한 원료유의 고형물을 제거 후 물과 수세하여 수용성 인지질을 수화하여 층 분리해 제거하고 상층의 오일은 추가적인 산 탈검을 수행한다. 그 뒤 세정을 통해 사용된 탈검제인 산과 추가적으로 수화된 인지질을 제거하게 된다. 이러한 3단계의 탈검 과정에서 하층으로 오일과 물이 폐기물로서 배출되며 본 연구에서는 배출 폐기물을 다시 층분리하여 오일층과 물 층으로 구분하여 유화유 제조에 사용되는 벙커C유, 물, 그리고 기존 유기계 및 무기계 유화제의 대체 가능성을 조사하였다. 유화 연료유는 기름과 물을 균일한 분산상으로 혼합한 연료유로 연소시 오일계 성분의 미연분을 감소시켜 연료 효율 제고와 배출가스 성상을 개선하기 위해 개발되어 왔다. 본 발표에서는 다양한 종류의 상용 첨가제 및 바이오디젤 원료유 생산 폐기물을 활용해 유화 연료유를 제조하였으며 각 유화유의 장시간의 상(phase) 안정성을 비교하였다. 바이오 폐기물 중에는 천연 계면활성제(surfactant)인 인지질이 다량 함유되어 있어 기존의 무기계 및 유기계 유화제보다 상 안정성이 우수하게 나타났으며 바이오디젤 원료유 생산 공정의 폐기물인 폐유과 폐수의 활용이 가능한 것으로 나타났다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.1025-1032
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• 1998

In this paper, the PLD design tool which realizes a digital circuit as PLD, by using EDIF netlist of the digital circuit designed at OrCAD have been developed. This paper is proposed the following algorithms: JIE(Joined Information Extractor) which extracts the connecting information between both cells in order to realize the digital circuit as PLD using the EDIF netlist, FND(Feedback Node Detector) which look into whether feedback exists or not, BEG(Boolean Equation Generator) which generates a boolean equation, and so on. Also, this paper is developed auto-select function which selects the PLD element with consideration of number of I/O variables of the minimized boolean equation, and algorithm generation JEDEC file of GAL6001 and GAL6002, having a forms of EPLD which is bigger than PLD.

• Journal of Energy Engineering
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• v.18 no.3
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• pp.169-174
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• 2009

In the study, the effect of the ultrasonic energy in transportational diesel fuel on the engine performance and exhaust emission has been investigated for indirect injection diesel engine. It was tested to estimated change of engine performance and exhaust emission characteristics for the transportational diesel fuels and the reforming fuels which was irradiated by the ultrasonic energy. The results of the study may be concluded as follows; By the irradiation of ultrasonic energy on the diesel fuel, cylinder pressure, heat release rate and engine power were increased but bsfc, mass fraction burned, and smoke were reduced. Also, the combustion was more stabilized and became complete and NOx was increased.

• Journal of dental hygiene science
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• v.16 no.6
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• pp.409-414
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• 2016

The purpose of this study was to evaluate the antibacterial effect of tea tree oil in denture cleaners. A self-curing denture resin was used to make the experimental specimen ($12mm{\times}2mm$). A saline solution was used as the control. To observe surface changes after cleaning, the microhardness and color of the experimental specimen's surface were analyzed. For the antibacterial activity test, Candida albicans was used. The microhardness and color of the surface remained unchanged after cleaning. The result of the antibacterial activity test revealed that the tea tree oil-containing solutions had a more enhanced antibacterial effect than did the saline solution. Therefore, these results suggest that the tea tree oil-containing solution is a promising denture cleaners.

• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.39-42
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• 2019

We report on the design of oil-water separators and the selection of materials for the effective application of highly selective membranes fabricated by commercial PET (polyester) fabrics. The waterproof ability of PET fabrics was optimized to improve the separation selectivity. The density of individual PET fabrics should be over $60g/m^2$, and the multi-layered structure is more favorable for the waterproof ability together with maintaining the removal efficiency. For the continuous adsorption and removal process, the rotating perforated cylinder was selected, and covered with membranes. Furthermore, more improved and stable removal efficiency was obtained by installing floating baffles which forces the oil content to move toward membranes.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.496-523
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• 2018

The objective of this study is to evaluate the economic feasibility of two fast pyrolysis and biooil upgrading (FPBU) plants including feed drying, fast pyrolysis by fluidized-bed, biooil recovery, hydro-processing for biooil upgrading, electricity generation, and wastewater treatment. The two FPBU plants are Case 1 of an FPBU plant with steam methane reforming (SMR) for $H_2$ generation (FPBU-HG, 20% yield), and Case 2 of an FPBU with external $H_2$ supply (FPBUEH, 25% yield). The process flow diagrams (PFDs) for the two plants were constructed, and the mass and energy balances were calculated, using a commercial process simulator (ASPEN Plus). A four-level economic potential approach (4-level EP) was used for techno-economic analysis (TEA) under the assumption of sawdust 100 t//d containing 40% water, 30% equity, capital expenditure equal to the equity, $H_2$ price of $1050/ton, and hydrocarbon yield from dried sawdust equal to 20 and 25 % for Case 1 and 2, respectively. TCI (total capital investment), TPC (total production cost), ASR (annual sales revenue), and MFSP (minimum fuel selling price) of Case 1 were $22.2 million, $3.98 million/yr, $4.64 million/yr, and $1.56/l, respectively. Those of Case 2 were $16.1 million, $5.20 million/yr, $5.55 million/yr, and $1.18/l, respectively. Both ROI (return on investment) and PBP (payback period) of Case 1(FPBU-HG) and Case 2(FPBU-EH) were the almost same. If the plant capacity increases into 1,500 t/d for Case 1 and Case 2, ROI would be improved into 15%/yr.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.475-481
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• 2019

The importance of performance-based design feedback is being emphasized when it comes to the potential impact that affects all the lifecycle of the building. However, the latency and disconnection of domain expert in the sector of AEC/FM remain current obstacles between design and performance feedback. It is hard to utilize performance feedback information for design exploration and support design decision making during the conceptual phase of design. Using parametric design, this paper proposes various design alternatives from a set of rules and constraints defined by algorithms for the geometric configurations of an Office Building. A Building Performance Analysis (BPA) was to developed using Autodesk® Revit® 2019 which integrates Autodesk® Green Building Studio® to predict its sufficient daylighting conditions of the LEED v4's Daylighting Autonomy (DA). The parametric-based performance feedback of this study outlines potential design improvements for further exploration in application to the early design process.

• The Journal of Society for e-Business Studies
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• v.4 no.3
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• pp.63-76
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• 1999

Internet-based electronic trade has been growing fast. But most users are not yet familiar with the system and find it very difficult to purchase and sell the products in the cyber market place. To handle these problems, agent-based virtual market place system has been proposed where agents instead of individuals participate in trading of goods. Most of the proposed models have been in the two general categories. The first is the direct transaction among sellers and buyers, and the second is the agent-based transaction. However, the transaction is not fair and the best deal can't be guaranteed for both models. In this paper, we propose a new broker based synchronous transaction algorithm which is fair to both parties and guarantees the best deal. Our algorithm is implemented using Visual C++ and the experimental results show that our method is better than the two traditional transaction models in every performance metrics, Number of transactions are increased up to 21% and price adjustment is up to 280% better for some transactions.

• Journal of environmental and Sanitary engineering
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• v.6 no.1
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• pp.103-108
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• 1991

Visibility studies are conducted in oxidizing organic compounds with ozone to investigate the oxidation in the waste and sewage water. While the ozone has been used as one of the major oxidation of the waste and sewage water, it is not effective to distroy the polluted organic compounds with the practical concentration in waste water treatment. The result are shown follows ; 1. Upon oxidizing organic compound with ozone, the former is much oxidized under three meters and the latter under the ABS waste water. 2. In case of being oxidized organics waste water with ozone codis, much removed under medicine and chemical waste water than anothers of primary treatment process. 3. The final treated waste water of oxidizing organics is higher than that of filtered water or sedimented water. Specially in organics waste water the colority after oxidizing decrease from 95% to 99.9% this suggests that any organic compounds produced during ozonation night be dissdved in the final treated waste water.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1108_1109
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• 2009

본 논문은 계통연계형 열병합 발전의 동작특성을 시뮬레이션을 통해 분석하는데 목적이 있다. 계통연계형 열병합 발전은 가스엔진, 영구자석형 동기발전기, 전력변환기로 구성되어 있는 것을 모델링하였다. 본 연구에서는 가스엔진이 일정속도로 동작하고 다극형 영구자석형 발전기에서 생산되는 400Hz 출력을 컨버터와 인버터로 구성되어 있는 전력변환기를 통해 상용주파수의 교류로 전력계통과 연계하는 것을 모의 하였다. 시뮬레이션은 PSCAD/EMTDC 프로그램을 이용하였고 시뮬레이션모델을 통해 다양한 시뮬레이션을 수행하였다. 그리고 실제모델의 축소 모형을 설계하여 하드웨어 시뮬레이터를 제작하였다.