• Journal of Environmental Science International
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• v.22 no.7
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• pp.905-913
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• 2013

We compared the applicability and economical efficiency of peroxone process with those of ozone process in the existing water treatment plant on downstream of Nakdong River. After comparing the peroxone process for removing geosmin with the ozone process in lab scale test, peroxone process showed much higher removal efficiency than the ozone process at the same ozone dosage. Proper range of $H_2O_2/O_3$ ratio were 0.5~1.0 and the half-life of geosmin was about 5.5~6.8 min when the $H_2O_2/O_3$ ratio was set to 0.5 during 1~2 mg/L of ozone dosage. Peroxone process could reduce the ozone dosage about 50 to maximum 30% for the same geosmin removal efficiency compared to the ozone process in the pilot scale test. In case of 1,4-dioxane treatment, peroxone process could have 3~4 times higher efficiency than ozone process at the same ozone dosage. The results of estimating the economical efficiency of ozone and peroxone process for treating geosmin and 1,4-dioxane by using pilot scale test, in case of the removal target was set to 85% for these two materials, the cost of peroxane process could be reduced about 1.5 times compared to ozone process, and in the same production cost peroxone process could have 2~3 times higher removal efficiency than ozone process. The removal efficiency by peroxone process showed a large difference depending on the physicochemical characteristics of target materials and raw water, therefore detailed examination should be carried out before appling peroxone process.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.2
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• pp.41-48
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• 2018

This study is expected to provide some basic data on how to apply more economical and efficient eco-friendly factors to reduce the carbon emissions. It has been scrutinized and analyzed the environmental factors of passive eco-friendly elements along with active eco-friendly elements as more efficient factors for energy conservation based on the case of a newly constructed broadcasting building with the green building certification in Sangam-dong DMC area. The first analysis was the energy consumption trends in Korea and the necessity of energy saving. Secondly, it was examined the energy consumption in the current status of the broadcasting building. Thirdly, it was looked into the correlation between the eco-friendly design application factors applied to the broadcasting building and the energy consumption types. As a result of the analysis, the application of fan and feed pump inverter along with ventilation system of waste heat recovery ventilation system were more meaningful in accordance with the economic feasibility of broadcasting buildings rather than economical effect of passive elements such as rooftop garden, reinforcement of building insulation. Also, the application of lighting control had the economical feasibility. Therefore, when it is intended to change the green building certification energy related evaluation items of the similar broadcasting building types, it is necessary to change the direction of adding weight to the more economical active element items in the future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.297-305
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• 2014

Nowadays new water supply projects have been on the decline as the water-power constructions have saturated, which means that the existing power equipment have slowly aged and they require more efforts to maintain the system performance. An effective asset management method of power equipment has become a great necessity from both economical and technical aspects. To be balanced, the asset management should look into all three parts: management, engineering, and information. The purpose of this paper is to study a Risk-Based Maintenance (RBM) matrix method through the deterioration evaluation algorithm for an efficient reliability assessment of oil-immersed power transformers by considering both asset management and technical evaluation. Make use of this result, the equipment will be decided to be replace or repair otherwise on service.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.511-514
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• 2005

In this study, LCC(Life Cycle Cost) evaluation technique is used for the purpose of accumulation of basic data required for such integrative system construction. We predicted the degradation time of concrete and repair material by neutralization through FEM analysis, and utilized the result for LCC evaluation It turned out that the repair method of construction in the most economical initial measure against degradation and a durable period can be chosen through the LCC evaluation in consideration of the degradation prediction using FEM analysis and the initial construction expense in a durable period and repair expense, and the number of repair times.

• KIEAE Journal
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• v.9 no.3
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• pp.21-27
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• 2009

The goal of this paper is to determine the suitability evaluation indices of a riverside reservoir space planning by classifying major indicators and calculating AHP(Analytical Hierarchy Process) based weights of them. The major indicators were set up based on literature review and questionnaire survey to experts. Four indicator categories were developed: location, environment, resource availability and economical efficiency. And they were divided into 12 sub-categories for calculating AHP-based weights. First, as for the major indicator categories, the calculation shows that the weighted index of environment is the most important at 0.458, followed by location at 0.128, economical efficiency at 0.170 and resource availability at 0.154. This suggests that environment is getting more public attention and the reservoir is regarded as a facility that is connected to a river. Those weight values were considered in calculating final weights for each of 12 sub-categories. Among them water quality and ecological environment take top ranks at 0.190 and 0.186, respectively. The lower ranks include access 0.112, resource availability of site 0.082, tourism resource 0.078, users 0.076, available land 0.052, area of site 0.031, shape of site and deterioration level 0.030 and percentage of private land 0.030 - which represents general considerations in other space planning. The difference of the top rank (water quality, 0.190) and the last one (percentage of private land, 0.027) is 0.163. The above result shows that users regard environmental aspect and resource availability more important than easiness of construction.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.171-178
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• 2016

Extensive efforts from all over the world have been made to solve energy problems, such as high oil prices, global warning due to the depletion of oil. Among them, biofuel has been drawing attention as a clean energy, which can replace fossil fuels. However, conventional biofuels were often converted from eatable biomass such as sugar cane, corn and soy which should be replaced with uneatable biomass. In this study, a techno-economical evaluation of the gasification of biomass waste with mixed alcohol synthesis process was performed. Considering available domestic biomass wastes, a 2000 ton/day conversion plant were assumed to produce 533000 L/day ethanol. Also, financial data from previous studies were evaluated and used and economical sensitivities with various operation conditions were established. Economic analysis were conducted by the payback period and internal rate of return (IRR) and net present value (NPV). Sensitivity analyses of raw material costs, initial investment, the major process cost, ethanol price changes and operating costs were all performed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.10
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• pp.991-1004
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• 2009

Operating experience of the various components in the nuclear power plants has shown that a variety of degradation mechanisms can occur during operation. Therefore, the accurate lifetime evaluation and systematic management are very important for the safe as well as the economical operation of the nuclear power plants. In this paper, the characteristics of a total of 17 degradation mechanisms were reviewed and the plausible degradation mechanisms such as stress corrosion cracking, fatigue, irradiation embrittlement, and so on, were identified. Also, the lifetime evaluation technologies which have been developed for the application to the domestic nuclear power plants are described. In addition, a total of 48 aging management programs which have been established for the safe operation of the various components are explained.

• Journal of Welding and Joining
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• v.12 no.2
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• pp.97-107
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• 1994

Both in-process quality control and high reliability of the weld is one of the major concerns in applying friction welding to the economical and qualified mass-production. No reliable nondestructive monitoring method is available at present to determine the real-time evaluation of automatic production quality control for friction welding of special hydraulic valve spool of 16mm in diameter. This paper, so that, presents the experimental examinations and statistical quantitative analysis of the correlation between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation periods of the welding and the tensile strength and other properties of the welded joints of $\phi16$ valve spool as well as the various welding variables, as a new approach which attempts finally to develop real-time quality monitoring system for friction welding.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.3
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• pp.124-135
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• 2000

This paper presents reasonable evaluation technique to determine system configuration of underground distribution system. To set up reasonable evaluation for a certain object region, it is necessary for methodology to access accurately factors such as economics, reliability, customer interruption cost, implementation and flexibility about proposed various configuration of underground distribution system. But it is difficult to evaluate factors as above-mentioned since there is no criterion to assess them in our country. Accordingly, having completed the technical and economical analysis and customer interruption cost of various types of system, this paper presents the most reasonable results to get the optimal configuration of underground distribution system. Also, this paper presents possible methodology which can be applied other areas having a different load characteristics by application actually making a selection Myungdong as sample area.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.325-328
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• 2006

Joint structures of composite truss bridges can have the same details for the connection between diagonal members and upper concrete slab as the connection between diagonal members and lower concrete slab. Adequate connection details should be decided according to design codes, constructibility, and economical evaluation. It is necessary to clarify the design check items and load transferring mechanism because combined external loads on composite truss bridges are concentrated at the joints. Joints with gusset plates and stud connectors are applied and complicated joint details may arise some problems in construction. This paper deals with experimental evaluation of the joints in composite truss bridges and proper design provisions were investigated to enhance the details. Push-out test specimens with group studs were fabricated and the effects of grouping and bent studs were studied.