• Corrosion Science and Technology
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• v.9 no.2
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• pp.92-97
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• 2010

Many kinds of alternative fuels such as biodiesel, ethanol, methanol, and natural gas have been developed in order to overcome the limited deposits in fossil fuels. In some cases, the alternative fuels have been reported to cause degrade materials. The corrosion rates of metals were measured by immersion test, a kind of time consuming test because low conductivity of these fuels was not allowed to employ electrochemical tests. With twin two-electrode cell newly designed for the study, however, electrochemical impedance spectroscopy (EIS) test was successfully applied to evaluation of the corrosion resistance ($R_p$) of zinc, iron, aluminum, and its alloys in an oxidized biodiesel and gasoline/ethanol solutions and the corrosion resistance from EIS was compared with the corrosion rate from immersion test. In biodiesel, $R_p$ increased in the order of zinc, iron, and aluminum, which agreed with the corrosion resistance measured from immersion test. In addition, on aluminum showing the best corrosion resistance ($R_p$), the effect of magnesium as an alloying element was evaluated in gasoline/ethanol solutions as well as the oxidized biodiesel. $R_p$ increased with addition of magnesium in gasoline/ethanol solutions containing chloride and the oxidized biodiesel. In the mean while, in gasoline/ethanol solutions containing formic acid, Al-Mg alloy added 1% magnesium had the highest $R_p$ and the further addition of magnesium decreased $R_p$. It can be explained with the fact that the addition of more than 1% magnesium increases the passive current density of Al-Mg alloys.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.234-236
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• 2006

Bioenergy emerges as a promising option for achieving the sustainable growth. However, bioenergy has poor cost competitiveness to the fossil fuels such as oil and coal. So many countries either developed or developing actively works for the implementation of various bioenergies. In this paper, the various supporting policies for the activation of the bioenergy business in the developed countries have been analyzed. Through the work, the desirable strategy for the promotion of bioenergy in our country have been suggested.

• International Journal of Railway
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• v.5 no.3
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• pp.117-123
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• 2012

According to the Intergovernmental Panel on Climate Change, combustion of petroleum-based and other fossil fuels results in the increasing atmospheric concentrations of $CO_2$ and other greenhouse gases (GHG's) and is a major contributing factor to global warming. This paper includes estimates of the energy and petroleum use and the GHG emissions caused by the transportation sector. It then examines the extent to which diversions to alternative modes may be possible. Estimates are made of the potential reductions in energy and petroleum use and GHG emissions resulting from diversions from conventional modes, to both low-speed urban and high-speed intercity maglev vehicle trips based on "well-to-wheel" (i.e. total-fuel-cycle) calculations.

• Atmosphere
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• v.19 no.1
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• pp.53-66
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• 2009

The purpose of this study is to describe the roles of carbon dioxide in the climate change, and carbon dioxide reduction policies in some countries. In addition, ways to cope with climate change in Korea are also discussed. Currently, global temperatures are rising due to the carbon dioxide produced by human beings. Global temperatures will rise approximately $6^{\circ}C$ until 2100 if we emit carbon dioxide at a present rate. Temperature rise will affect the terrestrial and oceanic resources, and ultimately influence the socio-economic structures including political stability. Most of the carbon dioxide comes from fossil fuels. Therefore, it is urgent to reduce the use of energy, which comes from fossil fuels. Solving the climate change due to the increases in carbon dioxide is a global problem. Korea should participate in the international community and cooperate with each other in order to reduce the carbon dioxide concentration. No policy was announced for the reduction of carbon dioxide so far. Korea should make a policy for the reduction of carbon dioxide in a specific year compared to that of certain standard year such as 1990 or 2005. Making policy should be based on the scientific result of the amount of carbon dioxide emitted and absorbed. Germanwatch announced the Climate Change Performance Index (CCPI) in order to evaluate an effort to reduce the carbon dioxide for 56 countries which emits 90 % of global carbon dioxide. Ranking for Korea is 51 among 56 countries. This clearly indicates that the appropriate carbon dioxide reduction has not been exercised yet in Korea. Researchers have a moral responsibility to provide updated new ideas and knowledges regarding climate change. Politicians should have a sharp insight to judge the ideas provided by researchers. People need an ethics to reduce the carbon dioxide in every day's life. Scientific research should not be influenced by stress caused by external budget and negative impact of capitalism. Science should be based on the pure curiosity.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.59-65
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• 2014

Diesel engines have the superior combustion efficiency and fuel economy that they are widely used for industry, heavyduty vehicles, etc. However, its exhaust emissions have become the major concerns due to their environmental impacts. Moreover, the depletion of fossil fuels is the main issue. Therefore, it is important to look for alternative sources of energy. Bio-diesel is one of the ideal energy which has proved to be ecofriendly for more than fossil fuels. The experimental tests analysed the engine performance and emission characteristics of a diesel engine using diesel and biodiesel blended of BD25, BD45 and BD65, in order to study the use of clean fuel to meet the increasingly stringent emission regulations. The engine performance was examined by using engine dynamometer while an exhaust gas analyzer was used to examine the emission characteristics. The effect of biodiesel on engine performance were lower to diesel through comparing their HP and torque but fuel consumption was slightly increased because of biodiesel has lower heating value and higher density than diesel. However, due to the better lubricity, the brake thermal efficiency of biodiesel was higher than diesel. The emission characteristics were strongly affected by the blending ratio of diesel and biodiesel. The results showed that the smoke opacity, hydrocarbons (HC) and carbon monoxide (CO) emissions decreased while the nitrogen oxides (NOX) slightly increased.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.339-362
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• 2018

In this paper, we simulate the contribution of an increasing renewable energy to demands for fossil fuels and power supply price by estimating a cost function for the Korean electric power generation sector. Since the renewable energy is a composite input, it is not feasible to compute the price index for renewable energy due to data limit. We estimate a restricted cost function, which is derived by minimizing the costs of fossil fuels conditional on the quantity of renewable energy set to its optimal level, jointly with supply relation. In particular, derivation of the shadow price of renewable energy would make it possible to analyze potential costs incurred by power plants.

• Journal of the Korean Professional Engineers Association
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• v.28 no.4
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• pp.14-20
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• 1995

Discourses on global environment are not only limited to the matter of simple environmen-tal protection but also going to an imperative that every country should take the environ-mental aspects into more consideration, and if necessary even proceed to modify its own strategies for economic growth. It is because scores of existing International conventions and agreements on environmental caused tend to combine the environmental issues with trade sanctions and financial assistances in order to ensure a mandatory power in pushing themselves through on a global dimension. Particularly noteworthy is the so -called Green Round(GR) which substantially associates the Issues of environmental protection with some sanctions in international trade, its rationale is quite simple. The differentiated production costs rising from the difference in environmental standards among different countries may affect national competitiveness in in-ternational trade, therefore a need does exist to countervail this difference. In reality, however, severe dissention seems to have been exposed between the developed and developing countries around this matter, because national interests and priorities in national goals considerably differ among respective countries. Greenhouse gases such as carbon dioxide which caused global warming are mostly released from the combustion of fossil fuels. The perfect removal of released $CO_{2}$ is impossible with existing technologies, and moreover, it's not payable in economical terms. Therefore it will be more effective and desirable to make more efforts to prevent the release of the $CO_{2}$ it- self through energy conservation involving the development and promotion of clean and high-efficient energy technologies and energy sources, and the development and promotion of new & renewable energy resources, and so on. One of important national tasks In our country is to establish an Energy Policy consider-ing environmental impacts since Korea depends most of its energy consumption on the fossil fuels such as oil and coal.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.73-84
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• 2015

Electricity generation using fossil fuels has caused environmental pollution. To solve this problem, research on new renewable energy sources (solar, wind power, geothermal heat, etc.) to replace fossil fuels is ongoing. These devices are able to generate power consistently. However, they have many weaknesses, such as high installation costs and limits to possible setup environments. Therefore, an active study on piezoelectric harvesting technology that is able to surmount the limitations of existing energy technologies is underway. Piezoelectric harvesting technology uses the piezoelectric effect, which occurs in crystals that generate voltage when stress is applied. Therefore, it has advantages, such as a wider installation base and lower technological costs. In this study, a piezoelectric harvesting device imitating seaweed, which has a consistent motion caused by fluid, is used. Thus, it can regenerate electricity at sea or on a bridge pillar, which has a constant turbulent flow. The components of the device include circuitry, springs, an electric generator, and balancing and buoyancy elements. Additionally, multiphysics analysis coupled with fluid, structure, and piezoelectric elements is conducted using COMSOL Multiphysics to evaluate performance. Through this program, displacement and electric power were analyzed, and the actual performance was confirmed by the experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1792-1797
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• 2013

Recently, due to the excessive use of fossil fuels, many studies about the fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be reason of power quality in the power system. In this paper, we constructed the system for an assessment on Islanding. The system is composed with power source, Impedance coordination load and linear load, fuel cell system. we are performed assessment on voltage and power quality in customer and the distributed power system during the Islanding of residential fuel cell system. In addition, no change in the impedance of power system, we made a islanding condition only using the actual load, As a variation of generation and load current under islanding, an analysis results based on assessment system showed that the power qualities of distribution system became more aggravation as effect of voltage sag and voltage swell phenomena.

• Environmental and Resource Economics Review
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• v.24 no.4
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• pp.727-745
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• 2015

This paper analyzes the firms' optimization behavior in response to rising demand for non-priced renewable energy in the manufacturing industries by using an input distance function. The annual estimates of the shadow price of renewable energy is derived and the trend of its shadow price over time is analyzed. The degree of substitution of renewable energy for fossil-fuels is examined. The input-based Malmquist productivity index, defined as a composite of the technical efficiency and technical change measures, is measured. The contribution of renewable energy input growth to the Malmquist index is analyzed. Empirical results indicate that the shadow price of renewable energy declined at an average annual rate of 17% over the period 1992-2012. Substitutability between renewable energy and fossil-fuels was limited. On average, a 1% increase in renewable energy would decrease Malmquist index by 0.04% per year.