• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.175.1-175.1
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• 2011

A rotating activated bacillus contactor (RABC) process with a series of aerobic reactors was tested in pilot scale to treat digested liquid from an anaerobic digester treating swine wastewater and sewage sludge. The influent (digested liquid) for the RABC process showed C/N ratios less than 2 as a typical feature of effluent from anaerobic digesters. The pilot process, which consists of three 3 RABC reactors, four aerobic tanks and a sedimentation tank, was operated for 210 days with a hydraulic retention time of 20 days without pH and temperature control. Since the Bacillus-enriched aerobic reactors shows high efficiencies of nitrogen removal at low DO levels less than 1.0 mg/L, they were operated at reduced aeration intensities. With relatively low concentrations of organics in comparison with nitrogen concentrations, the RABC process tested in this study showed stable and high nitrogen and organics removal efficiencies over 80%. The nitrogen removal process tested in this study was proven to be an effective and operation-cost saving (lower aeration) method to remove nitrogen without adding external carbon sources to meet the optimum C/N ratio.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.283-289
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• 2003

In order to establish the licensing review system for LILW disposal facility, we have studied the licensing review structure of oversea's countries, including United State, Japan, and France. We have also reviewed the domestic licensing review structure and the current status of development of safety standards for LILW management. A licensing review for LILW disposal facility can be implemented in 5-6 steps according to Atomic Energy Act. It is estimated to take 32 months for the CP and the OL review for LILW disposal facility referencing to the licensing review practice of the nuclear power plant. To date, a total of 15 MOST Notices have been developed to apply to the safe management of radwaste and 5 more MOST Notices will be developed by 2005.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.848-850
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• 2009

화석에너지 고갈로 인한 유가 상승으로 폐기물 에너지화가 이슈화 되고 있다. 폐기물 고형 연료 RDF는 에너지 문제를 해결하기위한 대안 중 하나로 수송성, 저장성, 연소안정성이 우수하나 환경오염 물질의 발생이 문제가 된다. 이러한 오염물질을 처리하기 위한 배가스 오염 물질처리를 위한 plant 설비 비용과 시간이 많이 투자된다. Aspen plus는 mass energy balance와 화학적평형, 열역학을 이용하여 공정 모사를 할 수 있는 프로그램으로 검증되었다. RDF의 삼성분, 원소분석, 발열량을 입력을 통해 HCl, SOx, NOx, CO의 배출량을 예측하고 이에 맞는 SNCR, SDA 등과 같은 반응기를 적용 하므로써 다양한 배가스 처리를 모사 할 수 있다. NOx를 제어하기위에 urea주입과 SOx와 HCl을 제거하기 위한 CaO를 주입을 모사 하므로써 실제 운영 적용 전 단계에 역할로 유용한 도구로 판단된다.

• Journal of Surface Science and Engineering
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• v.49 no.5
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• pp.447-453
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• 2016

In this study, we intended to extend the life of electropolishing solution through the reduction of electric resistance by improving the electrolysis efficiency. The optimum conditions were obtained by half round bus bar and Taguchi method. As the main control factors in the electropolishing process, current density, polishing time, electrolyte temperature and flow rate were selected. The electrolyte temperature was the most significant to the electrolysis efficiency. The optimum conditions for the life extension of electropolishing solution were as follows: current density, $45A/dm^2$; polishing time, 6 min; electrolyte temperature, $70^{\circ}C$; flow rate, 11 L/min. As a results of ANOVA of SN ratios, it was found that the electrolyte temperature was significant factor at the 90% confidence level.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.701-711
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• 2006

Sewage treatment plants located near to large cities emit extremely higher concentration of odorous materials. This study evaluated flux profiles of ammonia emitted from the water surface of sewage treatment plants using a dynamic flux chamber. Also, an ammonia overall mass transfer coefficient and a mass transfer model was developed in order to estimate fluxes of ammonia using environment parameters and the flux from the sewage treatment plants. The developed mass transfer model was evaluated through a fitness analysis. Comparison modeled flux applying empirical overall mass transfer coefficients of ammonia and measured ammonia flux show a high linearity with 0.977. The flux ratio of 1.282 demonstrated highly statistical fitness, also. Modeled flux using the mass transfer model was compared with measured flux. In result, it indicated that empirical overall mass transfer coefficients were similar to measured flux. The mass transfer model using the empirical overall mass transfer coefficient developed in this study was proved to be an easy and effective method to make accurate and precise predictions for ammonia flux discharged from sewage treatment plants.

• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.565-574
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• 2011

This paper aims to design a policy-assessment tool liking the Environmental Impact Assessment(EIA) and the Cost Benefit Analysis (CBA). As a step towards the incorporation of environmental and economic considerations, the approach used herein takes the form of integrating quantitative information on environmental benefits and costs associated with implementing the project into the existing framework of the EIA. Our case study is an project appraisal of a solar energy plant. It is confirmed that the technique is operational, however, there are certain limitations for a complete assessment. The difficulty mainly originated from the omission of important information from each step of the valuation process. Alternatively stated, some environmental services are not identified, nor quantified, and nor monetized in the process. More case studies are warranted in the future along with elaboration in methodology of techniques. In addition, the construction of a database on environmental values will be required to accumulate reliable and systematized data. These are the necessary conditions to improving quality in application of techniques as well as providing comprehensive and balanced information to decision makers.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.4
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• pp.227-233
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• 2014

Information presented in this study is intended to inform candidates as they prepare to design and structure the floatovoltaics solar power system. A developed floatovoltaics solar power generation results from the combination of PV plant technology and PV floating technology. This floating-based PV system is a new concept for PV development. The PV floating technology opens new opportunities to give value to unused areas so far while preserving valuable land for more adapted activities. Therefore the land-use conflicts are avoided and the environmental impact is minimized. Therefore the technology offers an interesting opportunity to regions facing on drought during summer time without any negative impact to the eco-system. This study describe the basic components of a floatovoltaics solar power system. A typical system consist of floating system and solar modules, a control device, rechargeable batteries, a load or device and the associated electrical connections. The floating system is specifically designed to keep all metallic components above water leaving only 100% recyclable, closed cell foam filled HDPE plastic floats in contact with the water. As the first case that can maximize the power generation efficiency of PV internationally, it is expected that this study will be utilized as a primary guide for future development of floating type PV system.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.377-379
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• 2001

When a wide area blackout occurres, reenergizing transmission lines should be done at first. The KEPCO(Korea Electric Power Corporation) divides whole power system grid into seven subsystem, and each subsystem has one of two blackstart power plants which are usually hydro or combined-combustion type, one priority power plant which should be first supplied with electric energy, and transmission lines between them. Voltage rising, line charging, and operation stability problem should be considered when these lines are reenergized. In this paper, building-up process for primary transmission system that should be energized at first is analyzed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.87-90
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• 2007

Fuel cell power system was developed for high-endurance unmanned aerial vehicle (UAV). Liquid chemical hydride was selected as a fuel due to its high energy density. Liquid storage of the fuel is an ideal alternative solution of the existing compressed hydrogen storage. The fueling system that extracts hydrogen from chemical hydride consists of catalytic reactor, micro-pump, fuel cartridge, separator, and controller. The fuel cell power system including the fueling system and the fuel cell that generates electricity was integrated into a proposed UAV. The performance verification of the fuel cell power system was performed to use as a power plant of the UAV.

• Structural Engineering and Mechanics
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• v.58 no.5
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• pp.799-823
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• 2016

A finite element model for the non-linear dynamic analysis of a reinforced concrete (RC) containment shell of a nuclear power plant subjected to extreme loads such as impact and earthquake is presented in this work. The impact is modeled by using an uncoupled approach in which a load function is applied at the impact zone. The earthquake load is modeled by prescribing ground accelerations at the base of the structure. The nuclear containment is discretized spatially by using 20-node brick finite elements. The concrete in compression is modeled by using a modified $Dr{\ddot{u}}cker$-Prager elasto-plastic constitutive law where strain rate effects are considered. Cracking of concrete is modeled by using a smeared cracking approach where the tension-stiffening effect is included via a strain-softening rule. A model based on fracture mechanics, using the concept of constant fracture energy release, is used to relate the strain softening effect to the element size in order to guaranty mesh independency in the numerical prediction. The reinforcing bars are represented by incorporated membrane elements with a von Mises elasto-plastic law. Two benchmarks are used to verify the numerical implementation of the present model. Results are presented graphically in terms of displacement histories and cracking patterns. Finally, the influence of the shear transfer model used for cracked concrete as well as the effect due to a base slab incorporation in the numerical modeling are analyzed.