• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.351-357
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• 2022

A conventional seawater reverse osmosis (SWRO) and a forward osmosis (FO) and reverse osmosis (RO) hybrid process to produce 1,000 m³/d of fresh water, were designed and compared in terms of carbon emission. When FO was adapted for the osmotic dilution, the required pressure for RO decreases, and thus energy consumption decreases. The decrease in carbon emission by decreased energy consumption (up to -0.73 kgCO₂/m³ using coal as the energy source) was compared with the increase in carbon emission by the FO system (+0.16 kgCO₂/m³), which is a function of various factors such as the number of FO modules and energy consumption. The comparison revealed that the FO-RO process causes less carbon emission compared with the SWRO process when the energy sources are coal and oil. However, if energy sources with low carbon emission such as solar, wind, and nuclear energy are selected, the carbon emission of the FO-RO process becomes higher than that of the SWRO process. This implies that the type of energy source is a key factor to determine the necessity of the FO-RO process from the aspect of carbon emission.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.337-347
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• 2016

Carbon dioxide ($CO_2$) and methane ($CH_4$) were measured in a rice-barley double cropping and rice mono cropping paddy fields, which are located in the southwestern coast of Korea, over a one-year period. Net ecosystems $CO_2$ exchange (NEE) and ecosystem respiration (Re) were estimated by the eddy covariance (EC) method, and an automatic open/close chamber (AOCC) method was used to measure $CH_4$ fluxes. Environmental factors (solar radiation, air temperature, precipitation etc.) were also measured along with fluxes. After the quality control and gap-filling, the observed fluxes were analyzed. As a result, NEE was -603.0 and $-471.5g\;C\;m^{-2}\;yr^{-1}$ in rice-barley double cropping and rice mono cropping paddy field, respectively. $CH_4$ emissions increased during the course of flooded days and were similar in two cropping paddy field. Accoding to rough results considering only fluxes of $CO_2$ and $CH_4$, it was estimated that the carbon absorbation in rice-barley double cropping paddy field was higher than that in rice mono cropping paddy field by $128.9g\;C\;m^{-2}\;yr^{-1}$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.162-176
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• 2021

Recently, Autonomous Vehicle(AV) has been expected to solve various transportation problems. s the problem of environmental pollution become serious, research to reduce pollution is needed. However, empirical research on AV related pollution is insufficient. Based on this background, this study analyzed network performance changes and CO₂ emissions introduc AVs and Electric Vehicles(EV) in eight intersections. The results show that when AVs with internal combustion engines were, the effect of carbon reduction over the network was insignificant. On the other hand, it was that the total amount of CO₂ generated in the network decreased significantly when EVs and autonomous electric vehicles were emissions in the transportation sector.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.263-271
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• 2009

This study aims to identify negotiation alternatives related to Post-2012 reducing emissions from deforestation (RED) and enhancement of forest carbon stock (EFCS) activities. It also aims to recommend a negotiation strategy considering environmental integrity and national interest on the basis of estimating reduction potentials of each alternative on the assumption that tradable carbon credits play an important role as positive incentives. In order to estimate greenhouse gas (GHG) reduction potentials and income potential from RED and EFCS activities, 99 countries were selected by the Global Forest Resources Assessment of the Food and Agriculture Organization of the United Nations. A 'baseline and credit' method was applied to estimate RED activities. Gross-net and net-net methods were applied for EFCS activities. According to the results, Brazil, Indonesia, and the Democratic Republic of Congo have more potential to get positive incentives through RED, while China, Chile, and the Republic of Korea have more potential to get positive incentives through EFCS. This study suggests including both RED and EFCS activities in the boundary of policy approaches and endowment of positive incentives to consider GHG reduction potentials in the global scale and equity among developing countries. Making a discount rate application of forest management activities can be also recommended to factor out the effects of human-induced activities by EFCS activities.

• Korean Journal of Ecology and Environment
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• v.51 no.2
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• pp.160-167
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• 2018

The role played by reservoirs in the biogeochemical cycles of elements is a subject of ongoing debate. Recent research has revealed that reservoirs emit significant levels of greenhouse gases. To assess the importance of reservoirs in monsoon climate areas as a source of methane gas into the atmosphere, we investigated variations in organic carbon (OC) input into the reservoir, oxic state changes, and finally the amount of methane emitted (focusing on the ebullition pathway) in Lake Soyang, which is the largest reservoir in South Korea. Total organic carbon (TOC) concentrations were higher during summer after two years of heavy rainfall. The sedimentation rates of particulate organic carbon (POC) and particulate organic nitrogen (PON) were higher in the epilimnion and hypolimnion than the metalimnioin, indicating that autochthonous and allochthonous carbon made separate contributions to the TOC. During stratification, oxygen depletion occurred in the hypolimnion due to the decomposition of organic matter. Under these conditions, $H_2S$ and $CH_4$ can be released from sediment. The methane emissions from the reservoir were much higher than from other natural lakes. However, the temporal and spatial variations of methane ebullition were huge, and were clearly dependent on many factors. Therefore, more research via a well-organized field campaign is needed to investigate methane emissions.

• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.159-165
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• 2016

BACKGROUND: Carbonized biomass is increasingly used as a tool of soil carbon sequestration. The objective of this study was to evaluate soil carbon storage to application of carbonized biomass derived from pear tree pruning.METHODS AND RESULTS: The carbonized biomass was a mobile pyrolyzer with field scale, which a reactor was operated about 400~500℃ for 5 hours. The treatments were consisted of a control without input of carbonized biomass and two levels of carbonized biomass inputs as 6.06 Mg/ha, C-1 and 12.12 Mg/ha, C-2. It was shown that the soil carbon pools were 49.3 Mg/ha for C-1, 57.8 Mg/ha for C-2 and 40.1 Mg/ha for the control after experimental periods. The contents of accumulated soil carbon pool were significantly (P < 0.001) increased with enhancing the carbonized biomass input amount. The slopes (1.496) of the regression equations are suggested that carbon storage from the soil was increased about 0.1496 Mg/ha with every 100 kg/ha of carbonized biomass input amount.CONCLUSION: Our results suggest that application of carbonized biomass would be increased the soil carbon contents due to a highly stable C-matrix of carbonized biomass. More long-term studies are needed to be proved how long does carbon stay in orchard soils.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.382-388
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• 2017

In response to the global warming crisis, the Kyoto protocol was established by major developed countries in 1997. The Paris Agreement, which imposes a carbon reduction obligation for both developed countries and developing countries, was signed in 2015. Regulations and efforts to reduce greenhouse gas emissions accordingly have been implemented. In this study, we analyzed the reduction of carbon emissions computerizing of the traditional project management system for efficient railway construction at Korea Rail Network Authority. We suggest a model that measures two major effects of carbon reduction, stemming from transportation and from a decrease of paper use. In this paper, we calculate the amount of carbon reduction and the economic effect of carbon reduction with application of the construction project management system at Korea Rail Network Authority. The model and methodology in this study are expected to be helpful to measure the carbon reduction performance for similar e-transformation.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.173-173
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• 2017

지구표면에서 발생하는 물순환, 에너지순환, 탄소순환은 토지-대기-식생간의 물리화학적 관계에 의하여 발생하며 이를 모사하기 위해 지면 및 기후모델이 활용된다. 본 연구에서는 NCAR의 지면모형인 Community Land Model(CLM) v4.5를 동아시아에 적용하고자 한다. 동아시아 범위에서 Fluxtower가 설치되어 물, 에너지, 탄소 플럭스 자료가 관측된 지점에서 모형을 구동하고 결과를 평가하였다. CLM 결과에 따른 증발산(Evapotranspiration), 잠열(Latent heat), 헌혈(Sensible heat)과 같은 물 및 에너지 순환에 관한 결과 뿐 아니라 총 일차생산량(Gross primary production), 순생태계순환(Net ecosystem exchange), 생태계 호흡량(Ecosystem respiration)과 같은 탄소순환에 관한 결과를 비교, 분석하였다. 특히, 기초 결과 분석에 따라 지면 모형 내의 여러 모듈 중에서 화재 관련 모듈에 초점을 맞추어 CLM 모형을 개선하였다. 화재는 식생의 성장에 많은 영향을 미치는 모듈로서 탄소순환 모의에 중요한 역할을 한다. 전 지구 대상 모의를 기반으로 하는 CLM에서 삼림 및 초지 지역의 화재 발생는 국내총생산(Gross domestic product, GDP) 및 인구밀도에 따라 모수화되어 있으나, 이는 전 지구 혹은 지역 대상이 아닌 지점 수준의 모형적용을 위해 부적합하다. 이에 관련 모수들을 재산정하고 개선된 모형 결과를 정량화하기 위해 위에서 언급한 물순환, 에너지순환, 탄소순환 관련된 변수들의 모의값을 Fluxtower 관측값과 비교, 분석하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.518-518
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• 2022

오늘날 우리사회는 환경변화와 기후 위기 가속화로 인하여 삶의 질 악화는 물론 인류 생존까지도 걱정해야 시기에 이르렀는데, 이러한 변화의 주범인 온실가스의 75%가 도시에서 발생되고 있다(Global Sustainable Development Repor, 2019), 이에 국제 사회는 도시 중심의 녹색 전환 정책 추진 중인데, 우리나라는 2017년부터 '도시재생뉴딜사업'을 추진하고 있다. 이에 본 연구는 지자체가 주도적으로 환경성과 창출 방안을 마련, 도시의 지속가능성 높이는데 일조하고자 탄소중립 선도 도시 사례와 도시재생의 문제점을 살펴봄으로써 도심 내 과밀화 문제와 탄소배출 해결 방안을 제시하였다. 당초 '도시재생뉴딜' 사업은 도시의 다양한 니즈를 충족시키기 위하여 시작되었으나, 최근에는 도시 노후화와 탄소배출 문제에 대응하기 위하여 '그린도시', '친환경 도시'를 지향하고 있다. 그러나 이를 뒷받침할 법·제도의 제·개정 및 이를 바라보는 이해관계자의 시각 전환이 이루어지지 않아 크고 작은 많은 문제점이 발생하고 있다. 도시재생의 첫 번째 문제점은 정책지원의 30% 이상이 일반근린형에 집중됨에 따라 주거형 도시재생 양상을 띄고 있다는 점이다. 이는 임기가 제한된 지자체장이 가시적인 성과를 위하여 도시 내 인프라 확충에 집중한 결과로 지속가능한 도시재생을 저하시키는 요인이 되고 있다. 두 번째, 도시재생 뉴딜사업이 계획수립과정에서 지속가능성에 대한 검토와 환경성 평가에 대한 고려 부족으로 기후 위기 대응에 미흡한 실정이다. 노후 도시의 주거 과밀화 문제를 해결하고 효과적인 도시 탄소 감축을 위하여 건물 - 마을 - 도시 등 여러 공간 단위의 온실가스 배출량 감축 전략 수립이 필요하다. 세 번째, 치·이수 위주의 도시재생 뉴딜사업으로 탄소 중립 대책이 미흡하다. 대응 방안으로는 자원의 관점에서 물 소비 감소 촉진 및 재생에너지 증가 전략이 필요하다.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.75-86
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• 1994

Garbage composting was studied in a controlled batch reactor with the addition of cooked rice as a biodegradable carbon source to find the effect of C/N ratio control on composting. And composting of bulking agents such as sawdust and wheat straw were tested with the addition of ammonium sulfate as a nitrogen source. As expected, biodegradation of the garbage having low C/N ratio was improved to some extent when foreign carbon was added. But bulking agents used in this study exerted slightly biodegradable carbon potential, indicating that the estimation of the dose of additional carbon considering desirable C/N ratio was not reasonable when lignocellulosic bulking material was added to garbage. It was found that the optimum moisture content increased with sawdust addition meaning the C/N ratio increment. Considering the above results, it was suggested that 78g sawdust per 100g garbage should be mixed to make C/N ratio to 25 and moisture content to 56% for effective composting of the garbage studied in this paper.