• Journal of Energy Engineering
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• v.26 no.4
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• pp.127-142
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• 2017

After individual consumption tax on bituminous coal has been imposed by Korean government after 2014 Jul, we analyse the influence of tax and conclude that the consumption of high calorie coal has been increased and that of low/middle calorie coal has been decreased. And also, the average calorie of coal consumption has been increased and the more fuel cost happens on account of the average calorie increase. Those effects have been caused by the current tax imposition system which does not reflect the bituminous coal trait. The motivation of oversea resource development and the effort of coal blending skill have been decreased because of the current tax policy. We suggest 2 ways of the tax policy improvement system[1. tax imposition system in proportion to 5,000kcal/kg, 2. 15 stages(1 stage : 200kcal/kg) segmentation tax imposition system equal to the tax/(5,000kcal/kg)] to increase the current tax amount, to prevent the coal consumption distortion and to remove the further fuel cost.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.36-44
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• 2017

The small commercial fuel cell is a new energy system that produces electricity and heat through electrochemical reaction between air and hydrogen. In Korea, hundreds of domestic small commercial fuel cell systems have been installed and operated every years and many parts in fuel cell systems depend on overseas products. KOGAS(Korea Gas Corporation) has developed the fuel processor which is an important part of fuel cell system and has evaluated the long-term durability. And KOGAS has evaluated domestic and overseas NG blower and fuel processor connected to NG blower. The fuel processor developed by KOGAS have maintained an efficiency of 76% and constant performance over 3,000 hours. The NG blower developed in Korea showed similar characteristics as overseas NG blower in the evaluation of power consumption according to rear pressure and outside temperature. The fuel processor module, fuel processor connected to BOP showed excellent performance.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.60-72
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• 2006

The aim of this paper is to identify and evaluate relations for forest greening and the firewood substitution for home use after 1945 Liberation of Korea. Korea faced serious forest degradation by the early 1960s due to the enormous firewood consumption, which was about ten million cubic meters annually, for home use. If the trend of firewood consumption was maintained until 1955's, the total forest area in Korea could be thoroughly degraded within 10 years. The firewood substitution for home use had to be solved as soon as possible. For this purpose, energy sector by the Ministry of Commerce and Industry carried out the substitution policy for home using the briquettes which was the only natural resources for energy produced in Korea. Firewood was prohibited being carried in the major cities by forestry sector, the Ministry of Agriculture and Forestry, from 1958. Only 5.2% of household in the cities used the forest products consumed as a fuel in 1970 because these inter-sectoral substitution measures of firewood for home use turned out a success gradually. After the 1970s, firewood consumption for home use was naturally decreased due to rural people's explosive move to cities, who were major consumers of firewood for home use at that time. Firewood for cooking was substituted by LPG gas after 1985 and firewood for house heating was substituted by coal and oil after 1980. Finally, on the basis of the firewood substitution for home use, the forest degradation that lasted over one hundred years was put a period.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.45-52
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• 2018

As guidelines for exhaust gases of ship are reinforced by the International Maritime Organization, the necessity for LNG fuelled ship is emerging. The relevant research is actively progressing to develop technologies and promote commercialization. When the residual quantity of LNG fuel tank is less than 70% by consuming fuel during operation, sloshing should be considered. We applied the Type C LNG fuel tank because medium sized LNG fuelled ships are difficult to equip with re-liquefaction system. Structural integrity and thermal performance are very important, especially in LNG fuel tanks that apply to LNG fuelled ship. Through this study, we proposed evaluation procedure of thermal performance for the Type C LNG tank, and verified the validity and effectiveness of BOR(Boil-Off Rate) test Procedure by comparing and analyzing changes in temperature, pressure, BOG(Boil-Off Gas).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.7
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• pp.609-615
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• 2015

In this study, the combustion and exhaust emission characteristics in a gasoline direct injection engine with variations of the bio-ethanol-gasoline blending ratio and the excess air factor were investigated. To investigate the effects of the excess air factor and the bio-ethanol blends with gasoline, combustion characteristics such as the in-cylinder combustion pressure, rate of heat release (ROHR), and the fuel consumption rate were analyzed. The reduction of exhaust emissions such as carbon monoxide (CO), unburned hydrocarbon (HC), and nitrogen oxides ($NO_x$) were compared with those of gasoline fuel with various excess air factors. The results showed that the peak combustion pressure and ROHR of bio-ethanol blends were slightly higher and were increased as bio-ethanol blending ratio is increased. Brake specific fuel consumption increased for a higher bio-ethanol blending ratio. The exhaust emissions decreased as the bio-ethanol blending ratio increased under all experimental conditions. The exhaust emissions of bio-ethanol fuels were lower than those of gasoline.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.469-475
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• 2008

In this paper, control of small PEM(Proton Exchange Membrane) fuel cell stack by a microprocessor is introduced. The water management of fuel cell stack inside, a key technique in fuel cell control, can be achieved by adjusting the required air flow for fuel and cooling, and by purging the excessive water from the stack. It is very important to precisely control the BOS(Balance of Stack) since the stable operation of the fuel cell system mainly depends on it. In this study the fuel efficiency of the system is improved by the control of the system based on the measured air flow and purge cycle during the optimal operation and its effectiveness is proved by the experiments. The operating stability of the system is improved by the developed controller using a microprocessor and it is expected to be widely used for the control of small PEM fuel cell stack.

• Fire Science and Engineering
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• v.30 no.3
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• pp.1-6
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• 2016

More than five thousands transportation fires occurannually in Korea and the resulting destruction of property and loss of life is huge and results in traffic and environmental pollution. The recent development of automobile technology such as the hybrid concept and use of bio fuels makes fire protection even more difficult due to a lack of understanding of the new adapted system including vehicle engines. In this study, a numerical simulation was performed on a PSR (perfectly Stirred Reactor) to simulate an automobile engine and to clarify the effect of gasoline/ethanol surrogates as a fuel. The temperature, NOx and soot emissions were predicted to decrease with increasing ethanol content, but that of unburned hydrocarbons was found to increase dramatically. The result will provide not only the basic thermal characteristics for engines and their after-treatment systems, but also make it possible to assess the potential for fire events in these systems when an ethanol mixed fuel is used in gasoline vehicles.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.61-72
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• 2014

This paper analyzed transition pathways toward a low carbon society in Korea to meet global $2^{\circ}C$ climate target. Lower economic growth, industrial structure change, enhance of energy demand management, decarbonization of power sector, and replacement of low carbon fuel could reduce greenhouse gas (GHG) emission from fuel combustion in 2050 by 67% against in 2011, or by 74% against in BAU (Business-As-Usual). Lower economic growth contributes to 13% of cumulative emission reduction relative to BAU, industrial structure change 9%, enhance of energy demand management 72%, decarbonization of power sector 5% and replacement of low carbon fuel 1% respectively. Final energy consumption in 2050 needs to be reduced to 50% relative to 2011, or to 41% relative to BAU. Nuclear, coal and renewable energy represent 31%, 40%, 2% respectively among electricity generation in 2011, but 38%, 2%, 32% in 2050. CCS represents 23% of total generation in 2050. Emission intensity of electricity in 2050 was decreased to 19% relative to 2011, or to 24% relative to BAU. Primary energy in 2050 was decreased to 64% compared to 2011, or to 44% compared to BAU. Final energy consumption, primary energy supply and GHG emission from fuel combustion from 1990 to 2011 increased by 176%, 197%, 146%. Radical change from historical trend is required to transit toward a low carbon society by 2050. Appropriate economic growth, structural change to non-energy intensive industries, energy technology research, development and deployment (RD&D) in terms of enhancement of energy efficiency and low carbon energy supply technologies, and fuel change to electricity and renewable energy are key instruments.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.6
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• pp.963-970
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• 1987

It has been a long time that black smoke emitted from buses and trucks powered with diesel engines, especially city-buses, came to be a serious air pollution problems in large cities as Seoul and Pusan. Therefore, proper means to reduce black smoke from diesel engines have to be considered as soon as possible, because it will take quite a long time to replace major passenger transportation system in cites from city-buses to subway. This paper, as a study on the reduction of diesel black smoke, showes how the black smoke of diesel engines can be reduced at various loads and engine speed by supplying small amount of gaseous fuel as LPG into the intake manifold. Thermal efficiency has been also considered for users, and confirmed through the engine test.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.19-31
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• 1993

디젤자동차는 가솔린 자동차에 비하여 연료소비효율(fuel economy)이 20-30% 정도 높고 고출력을 낼수 있어 이의 수요가 증가하고 있다. 본 고에서는 디젤자동차에서 배출되는 수많은 화학물질중에서 문제가 되고 있는 입자상물질, NOx 및 SO$_{2}$를 제거하는 기술에 대하여 살펴본다. 이러한 오염물질의 저감을 위하여는 배기가스 재순환, 분사시기의 조절, 인터쿨링 같은 연소기술의 개선과 유황분이 적고, 방향족화합물의 함량이 적은 청정연료를 사용하여 어느 수준까지는 목적을 달성할 수 있다. 1. 디젤자동차 배출허용기준. 2. 배기가스 정화기술. 2.1 트랩기술(trap technology). 2.2 재생기술(regeneration technology). 2.3 제어 및 센서기술(control and sensor technology)