• New & Renewable Energy
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• v.19 no.4
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• pp.61-71
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• 2023

The necessity of energy utilization using livestock manure has been proposed with the decrease in domestic agricultural land. Livestock manure solid fuel has been investigated as a promising energy resource owing to its convenient storage and use in agricultural and livestock fields. Additional electricity production is possible through the integration of a biomass combustion boiler with the organic Rankine cycle (ORC). In this study, a mathematical system model of the cattle manure solid fuel boiler integrated with the ORC was developed to analyze the components' performance under variable operating conditions. A sensitivity analysis was conducted to confirm the electrical efficiency of the ORC turbine and the applicability of this system. The minimum required waste heat recovery rate was derived considering the system marginal price and levelized cost of electricity of the ORC. The simulation results showed that, in Korea, more than 77.98% of waste heat recovery and utilization in ORC turbines is required to achieve economic feasibility through ORC application.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3236-3240
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• 2007

This paper describes the results of steam turbine performance tests. The objectives of performance test is to exactly evaluate the degradation(decrease in performance) of the coal-fired steam turbine generator in order to provide plant information to help performance engineers identify problems, improve performance, and make economic decisions about scheduling maintenance and optimizing operation. To achieve these goals, the periodic thermal performance tests have been carried out since the initial operation period, 1997. We made the calculation program and guidelines for the tests and developed the performance index of the turbine cycle on the basis of the ASME PTC. By comparing the performance changes throughout the whole operation period, we confirmed the performance reliabilities of the turbine and its conditions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.3
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• pp.135-142
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• 2006

Engineers are always concerned with life cycle costs for making important economic decisions through engineering action like reliability of products. Decisions during the reliability growth development of products involve trade-offs between invested costs and its returns. In order to find minimal LCC containing the reliability improvement cost, production cost, repair and replacement costs, and holding cost of spare parts for failure items we suggest in this paper relationship between development cost and sustaining cost in values of growth parameter $\beta$ of AMSAA model. This model is applied to the reliability growth program based on AMSAA model during R&D phase, the warranty activities of items and the block replacement policy for maintenance of items in avionic equipment.

• Journal of the Korea Institute of Building Construction
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• v.3 no.4
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• pp.129-134
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• 2003

The purpose of this study is to evaluate efficiency by the Life Cycle Cost(LCC) analysis of floor covering materials for remodeling. This study has been performed as a case study. The LCC analysis is a technique which takes account into both initial-future costs and benefits of an investment over some period of time. LCC is important in commercial decision making because it provides improved assessment of the living-term cost effectiveness of construction projects as well as alternative economic methods that focus on initial costs. For LCC analysis and comparison, the present value technique is used. The results of this study are summarized as follows; (1) A LCC analysis model of floor covering materials is suggested through a case study (2) As a result of LCC case study, the type of sheet is analysed more economical than that of tile in floor covering materials.

• Journal of the Korean Society of Combustion
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• v.18 no.3
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• pp.1-8
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• 2013

Thermodynamic and economic analyses of various types of gas turbine combined cycle power plants have been performed to establish criteria for optimization of power plants. The concept of efficiency, in terms of the difference in energy levels of electricity and heat, was introduced. The efficiency of power and heat generation by power plants with other purposes was estimated, and power generation costs were figured out for various types of combined heat and power plants(i.e., fired and unfired, condensing and non-condensing modes, single or double pressure HRSG).

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.176-178
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• 2004

HTS (High Temperature Superconducting) Transformer has the several useful characteristics in the viewpoints of technical and economical. Especially, an HTS transformer replaces the copper wire coils in a conventional transformer with lower loss HTS wire In addition, inexpensive, environmentally benign liquid nitrogen replaces the conventional oil as the electrical insulation (dielectric) and provides the necessary cooling for the HTS transformer Therefore, the Life-cycle cost of an HTS transformer is much more attractive than conventional because it is more energy efficient, lighter in weight, smaller in size, and environmentally compliant. HTS transformer can be the best way to replace with conventional transformer in the future. In this paper, we investigate the expected price of HTS transformer to have a merit in viewpoint of economic aspect. First, life-cycle cost of conventional transformer is calculated and based on this, the expected price of HTS transformer is evaluated, which HTS transformer is competitive against conventional transformer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.289-289
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• 2007

Spinel structured $LiMn_2O_4$ is more economic and environmental friendly to be used as commercial active material for secondary battery compared to Co-oxide material active material, but spinel structure of $LiMn_2O_4$ is unstable and its capacitance decreases with increase of cycle. Therefore, the purpose of our sturdy is to improve the stability of $LiMn_2O_4$ spinel structure and increase its capacitance by using substituents or dopants. $LiMn_2O_4$ powder was synthesized by charging substituents or dopants mole fractions, and temperatures. Crystal state, structure and specific surface area of the synthesized powder were measured and also characteried electrochemically by measuring its impedance, charge-discharge capacitance and etc.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.531-547
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• 2014

This study analyzed the effect of Greenhouse of wood pellet fuel conversing from Diesel. Analyzed through a life cycle assessment of greenhouse gas emissions of carbon dioxide for the environmental assessment, In evaluation of the Ministry of the Environment, analyzed through the life cycle assessment of carbon dioxide emissions of the greenhouse gas and, In the case of economic evaluation, we analyzed the investment payback period to the total revenue generated by each of the calculated incentive based on the RHI and institutions reduction projects a reduction of costs associated with the reduction of fuel costs.

• 사회경제평론
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• no.38
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• pp.241-259
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• 2012

This paper reviews four different kinds of currency crisis models proposed to explain the Korean crisis of 1997 to examine which model is more relevant to explain the Korean crisis of 2008. According to the author's investigation, the 'Frenkel-Neftci' cycle is more relevant model to interpret the Korean crisis of 2008. In 2008, spreads opened due to, first, high interest rate policy by the Korean government aimed to suppress real estate price increase, and, second, the expectation about exchange rate appreciation, and thirdly stock market returns after recovering the crisis. Then the international capital market catastrophe due to the subprime crises produced the sudden change of expectation of the market participants. Huge capital outflows resulted from the credit crunch in the international capital markets, and the possibility of exchange rate depreciation by the Korean government to promote exports in the course of the global recession.

• Nuclear Engineering and Technology
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• v.46 no.1
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• pp.81-92
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• 2014

This study suggests 5 evaluation criteria (safety and technology, environmental impact, economic feasibility, social factors, and institutional factors) and 24 evaluation indicators for a NFC (nuclear fuel cycle) derived using factor analysis. To do so, a survey using 1 on 1 interview was given to nuclear energy experts and local residents who live near nuclear power plants. In addition, by conducting a factor analysis, homogeneous evaluation indicators were grouped with the same evaluation criteria, and unnecessary evaluation criteria and evaluation indicators were dropped out. As a result of analyzing the weight of evaluation criteria with the sample of nuclear power experts and the general public, both sides recognized safety as the most important evaluation criterion, and the social factors such as public acceptance appeared to be ranked as more important evaluation criteria by the nuclear energy experts than the general public.