• Journal of the Korean Geographical Society
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• 제43권1호
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• pp.1-19
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• 2008

This study intends to clarify the characteristics and causes of current changes in wintertime precipitation in Korea and to predict the future directions based on surface observational $(1973/04\sim2006/07)$ and modeled (GFDL 2.1) climate data. Analyses of surface observation data demonstrate that without changes in the total amount of precipitation, snowfall in winter (November-April) has reduced by 4.3cm/decade over the $1973\sim2007$ period. Moreover, the frequency and intensity of snowfall have decreased; the duration of snow season has shortened; and the snow-to-rain day ratio (STDR) has decreased. These patterns indicate that the type of wintertime precipitation has changed from snow to rain in recent decades. The snow-to-rain change in winter is associated with the increases of air temperature (AT) over South Korea. Analyses of synoptic charts reveal that the warming pattern is associated with the formation of a positive pressure anomaly core over northeast Asia by a hemispheric positive winter Arctic Oscillation (AO) mode. Moreover, the differentiated warming of AT versus sea surface temperature (SST) under the high pressure anomaly core reduces the air-sea temperature gradient, and subsequently it increases the atmospheric stability above oceans, which is associated with less formation of snow cloud. Comparisons of modeled data between torrent $(1981\sim2000)$ and future $(2081\sim2100)$ periods suggest that the intensified warming with larger anthropogenic greenhouse gas emission in the $21^{st}$ century will amplify the magnitude of these changes. More reduction of snow impossible days as well as more abbreviation of snow seasons is predicted in the $21^{st}$ century.

• Asian-Australasian Journal of Animal Sciences
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• 제24권2호
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• pp.285-294
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• 2011

The abatement of methane emission from ruminants is an important global issue due to its contribution to greenhouse gas with carbon dioxide. Methane is generated in the rumen by methanogens (archaea) that utilize metabolic hydrogen ($H_2$) to reduce carbon dioxide, and is a significant electron sink in the rumen ecosystem. Therefore, the competition for hydrogen used for methanogenesis with alternative reductions of rumen microbes should be an effective option to reduce rumen methanogenesis. Some methanogens parasitically survive on the surface of ciliate protozoa, so that defaunation or decrease in protozoa number might contribute to abate methanogenesis. The most important issue for mitigation of rumen methanogenesis with manipulators is to secure safety for animals and their products and the environment. In this respect, prophylactic effects of probiotics, prebiotics and miscellaneous compounds to mitigate rumen methanogenesis have been developed instead of antibiotics, ionophores such as monensin, and lasalocid in Japan. Nitrate suppresses rumen methanogenesis by its reducing reaction in the rumen. However, excess intake of nitrate causes intoxication due to nitrite accumulation, which induces methemoglobinemia. The nitrite accumulation is attributed to a relatively higher rate of nitrate reduction to nitrite than nitrite to ammonia via nitroxyl and hydroxylamine. The in vitro and in vivo trials have been conducted to clarify the prophylactic effects of L-cysteine, some strains of lactic acid bacteria and yeast and/or ${\beta}$1-4 galactooligosaccharide on nitrate-nitrite intoxication and methanogenesis. The administration of nitrate with ${\beta}$1-4 galacto-oligosaccharide, Candida kefyr, and Lactococcus lactis subsp. lactis were suggested to possibly control rumen methanogenesis and prevent nitrite formation in the rumen. For prebiotics, nisin which is a bacteriocin produced by Lactococcus lactis subsp. lactis has been demonstrated to abate rumen methanogenesis in the same manner as monensin. A protein resistant anti-microbe (PRA) has been isolated from Lactobacillus plantarum as a manipulator to mitigate rumen methanogenesis. Recently, hydrogen peroxide was identified as a part of the manipulating effect of PRA on rumen methanogenesis. The suppressing effects of secondary metabolites from plants such as saponin and tannin on rumen methanogenesis have been examined. Especially, yucca schidigera extract, sarsaponin (steroidal glycosides), can suppress rumen methanogenesis thereby improving protein utilization efficiency. The cashew nutshell liquid (CNSL), or cashew shell oil, which is a natural resin found in the honeycomb structure of the cashew nutshell has been found to mitigate rumen methanogenesis. In an attempt to seek manipulators in the section on methane belching from ruminants, the arrangement of an inventory of mitigation technologies available for the Clean Development Mechanism (CDM) and Joint Implementation (JI) in the Kyoto mechanism has been advancing to target ruminant livestock in Asian and Pacific regions.

• Land and Housing Review
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• 제9권2호
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• pp.41-50
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• 2018

The purpose of this study is to review the U.S. renewable energy policies implemented by the federal government and the state governments to investigate potential barriers of renewable energy expansion and to develop policy implications for the successful renewable energy policy making in Korea. Recently, the restructuring in the energy supply chain has been being a new trend in many countries that shows a transition from traditional fossil fuels to sustainable renewable energy sources. The United States has enforced effective renewable energy policies (i.e., regulatory policies, financial incentives), which have led to the exploding growth of renewable energy facilities and productions over the last ten years. For example, many state governments in the U.S. are implementing Renewable Portfolio Standard (RPS) policies that require increased energy supply from renewable energy sources (i.e., solar, wind and geothermal). These RPS policies are expected to account for at least 10-50 percent of total electricity production in the next fifteen years. As part of results, in the recent three years, renewable energy in the U.S provided over 50 percent of total new power generation constructions. On the other hand, Korea initiated to develop climate change policies in 2008 for the Green Growth Policy that set up a target reduction of national Greenhouse Gas (GHG) emissions up to 37 percent by 2025. However, statistical data for accumulated renewable energy capacity refer that Korea is still in its early stage that contribute to only 7 percent of the total electricity production capacity and of which hydroelectric power occupied most of the production. Thus, new administration in Korea announced a new renewable energy policy (Renewable Energy 3020 Plan) in 2017 that will require over 95 percent of the total new generations as renewable energy facilities to achieve up to 20 percent of the total electricity production from renewable energy sources by 2030. However, to date, there have not been enough studies to figure out the barriers of the current policy environment and to develop implications about renewable energy policies to support the government plan in Korea. Therefore, this study reviewed the U.S. renewable energy policies compared with Korean policies that could show model cases to introduce related policies and to develop improved incentives to rapidly spread out renewable energy facilities in Korea.

• Asian-Australasian Journal of Animal Sciences
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• 제17권3호
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• pp.349-354
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• 2004

The effects of probiotic-vitacogen and galacto-oligosaccharides (GOS) supplementation on methanogesis, energy and nitrogen utilization in replacement dairy cows were evaluated. A basal diet comprising orchardgrass hay, lucerne hay cube and concentrate (2:2:1, DM basis) were fed with or without supplements to four cows at $80g\;DM/kgBW^{0.75}$per day in a $4{\times}4$ Latin square arrangement. The four treatments were; 1) basal diet, 2) basal diet plus 100 g probiotic-vitacogen, 3) basal diet plus 50 g GOS, 4) basal diet plus 50 g GOS and 100 g probiotic-vitacogen. Nutrient apparent digestibility was not altered by the effect of supplementation. Nitrogen intake was significantly (p<0.001) higher for the two vitacogen-supplemented diets compared to control and GOS supplemented diets. However, vitacogen supplemented diets had numerically higher fecal and urinary nitrogen losses, thereby, having lower nitrogen retention compared to control and GOS supplemented diets. Gross energy intake was also significantly (p<0.05) higher for vitacogen-supplemented diets compared to control and GOS diets, however, due to higher losses in feces, urine, methane and heat, GOS supplemented diet had numerically higher energy retention. There was an 11% reduction in methane emission (liters/day) in GOS supplemented diet compared to control diet. However, the combination of GOS with vitacogen resulted in an increased methane emission. When expressed per unit of animal production (g/kg live-weight gain), methane production tended to be lower in vitacogensupplemented diets compared to control and GOS diets. The supplementation of replacement dairy cows with GOS reduced methane emission (liters/day), while, vitacogen supplementation reduced methane emission per unit animal production. The two feed supplements may contribute to the abatement of methane as a greenhouse gas.

• Environmental and Resource Economics Review
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• 제23권2호
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• pp.157-185
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• 2014

The Kyoto Protocol has extended its life until 2020 by the decision at COP18 in Doha, Qatar in 2012. So has the Kyoto Mechanism of CDM, JI, and ETS. Nonetheless, the sustainability of CDM projects is jeopardized by the recent rule changes in the international emissions trade market such as EU ETS and the price decrease in emission credits. In particular, the domestic CDM projects reducing non-$CO_2$ GHG emissions are being directly affected. This study examines the trend of carbon credit price change in the international market. It also examines how the rule changes in the international emissions trade market have affected domestic non-$CO_2$ CDM projects through which mechanisms. The policy implications drawn from this study is two-fold: it suggests how the government can assist the project developers in utilizing GHG emission reduction technologies and the market in promoting investment environment before the domestic ETS enters into effect in 2015; apart from possible measures within ETS, an additional measures such as bilateral carbon offset system is suggested to help the private sector reduce uncertainty in investment and increase options to choose.

• Environmental and Resource Economics Review
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• 제16권3호
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• pp.485-510
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• 2007

The purpose of this paper is to empirically analyze the economic effect of energy saving investment on the improvement of energy intensity. The data used in this paper are panel data, both time-series and cross-section data. In addition, eight manufacturing sectors has been divided into two groups: massive energy consuming (four industries) and non-massive energy consuming (four industries) ones and the time period of analysis is from 1982 to 2004. According to the empirical results, firstly, energy saving investment has a negative relationship with energy intensity, however, its effect is not high in terms of absolute volume of energy consuming. Secondly, in improving energy intensity of energy saving investment, its elasticity IS higher in non-massive energy consuming sector compared it with massive energy consuming sector. Thirdly, automation investment is also playing an important role in energy conservation. The elasticities of automation investment to energy intensity are larger than those of energy saving investment. In terms of the reduction of greenhouse gas per investment unit cost, however, energy saving investment has larger effect than automation investment.

• Journal of the Korean Society for Marine Environment & Energy
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• 제14권1호
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• pp.51-64
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• 2011

Carbon dioxide Capture and Storage (CCS) is one of the key players in greenhouse gas (GHG) reduction portfolio for mitigating climate change. CCS makes simultaneously it possible not only to reduce a huge amount of carbon dioxide directly from the emission sources (e.g., coal power plant) but also to maintain the carbon concentrated-energy and/or industry infrastructure. Internationally, the United Nations Framework Convention on Climate Change (UNFCCC) is dealing the agenda for considering the possibility of including CCS project as one of Clean Development Mechanism (CDM) projects. Despite its usefulness, however, there are the controversies in including CCS as the CDM project, whose issues include i) non-permanence, including long-term permanence, ii) measuring, reporting and verification (MRV), iii) environmental impacts, iv) project activity boundaries, v) international law, vi) liability, vii) the potential for perverse outcomes, viii) safety, and ix) insurance coverage and compensation for damages caused due to seepage or leakage. In this paper, those issues in considering CCS as CDM are summarized and analyzed in order to suggest some considerations to policy makers in realizing the CCS project in Korea in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• 제17권2호
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• pp.101-109
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• 2013

Recently, it is certain that the increase of heating and cooling energy consumption by radical change in climate condition has caused serious problems related to environmental and energy concerns associated with increase of fossil fuel usage and carbon dioxide production as well as global warming. So, various actions to reduce greenhouse gas exhaustion and energy consumption have been prepared by world developed countries. Our government has also been trying to seek energy control methods for houses and buildings by proclaiming political polices on low-carbon green growth and construction and performance standards for environment-friendly housing. The energy consumption by buildings approximately reaches 25% of total korea energy consumption, and the increasing rate of energy consumption by buildings is stiffer than the rate by the other industries. The greatest part in the buildings of the energy consumption is building facade. While lots of research projects for reducing energy consumption of the facade have been conducted, but a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research presents here a study to improve the insulation property of structural concrete formed by micro form admixture (MFA) with experimentally reviewing the physical, mechanical and thermal characteristics of the concrete. As the results of this experiment, in the case of concrete mixed with MFA, slump loss has been improved. As the mixing ratio of MFA increases, the compressive strength is decreased and thermal conductivity is increased. Also it was found that water-cement ratio increases, the compressive strength is decreased and thermal conductivity is increased. but, there was not big influence by the change of fine aggregate ratio.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.631-640
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• 2018

The application of an oxy-combustion circulating fluidized bed combustor (Oxy-CFBC) for low grade coals has recently developed in the world to meet the continuous increase of energy demand and to achieve the reduction of greenhouse gases. Since demo plants for Oxy-CFBC have been developed, the combustion properties of Oxy-CFBC in various operation conditions, such as gas flow rates, combustion temperature, fuel, and so on, should be investigated to develop design criteria for a commercial Oxy-CFBC. In this study, a computational simulation tool for Oxy-CFBC was developed on the basis of the IEA-CFBC (International Energy Agency Circulating Fluidized Bed Combustor) model. Simulation was performed under various conditions such as reaction temperature ($800^{\circ}C{\sim}900^{\circ}C$), oxygen contents (21%~41%), coal feeding rate, Ca/S mole ratio (1.5~4.0), and so on. Simulation results show that the combustion furnace temperature is higher in oxy 1 than air fired. However, the temperature gradient tended to decrease with increasing oxy mixing percent. In case of $SO_x$, the higher the Ca/S mole ratio and oxy mixing percent, the higher the desulfurization efficiency.

• Clean Technology
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• 제24권1호
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• pp.50-54
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• 2018

In this work, N-methyl-2-pyrrolidone (NMP) was added into diethylenetriamine (DETA) aqueous solution for high $CO_2$ loading via phase splitting of absorbents during $CO_2$ absorption. Immiscible two phases were formed in the range of more than 30 wt% of NMP in 2 M DETA + NMP + water absorbents because of low solubility of DETA-carbamate in NMP solution. As the composition of NMP in the absorbents increased, the difference of $CO_2$ loading between each phase increased and the volume of bottom phase decreased. In $CO_2$ absorption in packed column by 2 M DETA + NMP + water absorbents, the absorption rate decreased in the range of more than 40 wt% of NMP. It is due to the increasing of mass transfer resistance in liquid film of absorbents at the high concentration of NMP. DETA + NMP + water absorbent is expected as the promising one for reducing the regeneration energy of absorbents according to volume reduction of $CO_2-rich$ phase.