• Journal of the Korean Institute of Gas
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• v.15 no.1
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• pp.9-14
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• 2011

Heavy duty diesel engine has relatively small portion of whole vehicles due to long drive distance and large engine displacement, but largely influences atmosphere environment. City buses changed to CNG (Compressed Natural Gas) bus with Korea-Japan Worldcup. Heavy duty truck and intercity bus, however, were impossible to use CNG because those kinds of vehicles had long drive distance and CNG station was installed mainly at the around of the bus garage of city. Insulation container storing the natural gas as a liquid makes heavy duty truck and intercity bus possible to use the natural gas. Drive using diesel is possible where is hard to recharge the gas. With LNG (Liquefied Natural Gas), the dependence on oil is largely decreased, PM (Particulate Matter) and NOx which is chronic disadvantage of diesel is remarkably reduced and finally $CO_2$, the representative green house gas, is reduced over 10%.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.5
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• pp.153-160
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• 2020

Energy Consumption Predictions for Industries has a prominent role to play in the energy management and control system as dynamic and seasonal changes are occurring in energy demand and supply. This paper introduces and explores the steel industry's predictive models of energy consumption. The data used includes lagging and leading reactive power lagging and leading current variable, emission of carbon dioxide (tCO2) and load type. Four statistical models are trained and tested in the test set: (a) Linear Regression (LR), (b) Radial Kernel Support Vector Machine (SVM RBF), (c) Gradient Boosting Machine (GBM), and (d) Random Forest (RF). Root Mean Squared Error (RMSE), Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE) are used for calculating regression model predictive performance. When using all the predictors, the best model RF can provide RMSE value 7.33 in the test set.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.91-100
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• 2007

This study suggests direct connection service which has advantage of high-speed operation of KTX and access convenience of general train, and Pre-feasibility studies on the direct connection service. And analyze transportation demand change by the method as follows; It is to analyze the demand change of before and after KTX operation by previous transport data of Gyeongbu line, and calculate the coefficient of utilization using triggering demand by opening the 2nd phase of Gyeongbu line (Dongdaegu${\sim}$Busan). Through Pre-feasibility analysis, reduction $70{\sim}100$ minutes of train travel time and total revenue will increase about $100 thousand per day. Also, there will be environment-friendly effects of decreasing $CO_2$ emissions. But, Direct connection service need to highly cost ; Buying and Operation cost of KTX train. Therefore, we will be get more correct result of Pre-feasibility study on direct connection service, if there are concrete on buying the KTX action plans.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.23-30
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• 2007

The ultimate objective of this study is to develop oxygen-enriched combustion techniques applicable to the system of practical industrial boiler. To this end the combustion characteristics of lab-scale LNG combustor were investigated as a first step using the method of numerical simulation by analyzing the flame characteristics and pollutant emission behaviour as a function of oxygen enrichment level. Several useful conclusions could be drawn based on this study. First of all, the increase of oxygen enrichment level instead of air caused long and thin flame called laminar flame feature. This was in good agreement with experimental results appeared in open literature and explained by the effect of the decrease of turbulent mixing due to the decrease of absolute amount of oxidizer flow rate by the absence of the nitrogen species. Further, as expected, oxygen enrichment increased the flame temperatures to a significant level together with concentrations of $CO_2$ and $H_2O$ species because of the elimination of the heat sink and dilution effects by the presence of $N_2$ inert gas. However, the increased flame temperature with $O_2$ enriched air showed the high possibility of the generation of thermal $NO_x$ if nitrogen species were present. In order to remedy the problem caused by the oxygen-enriched combustion, the appropriate amount of recirculation $CO_2$ gas was desirable to enhance the turbulent mixing and thereby flame stability and further optimum determination of operational conditions were necessary. For example, the adjustment of burner with swirl angle of $30\sim45^{\circ}$ increased the combustion efficiency of LNG fuel and simultaneously dropped the $NO_x$ formation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.474-481
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• 2018

The policy-making and technological development of eco-friendly automobiles designed to increase their supply is ongoing, but the internal combustion engine still accounts for approximately 95% of automobiles in use. To meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is increasing continuously. As diesel engines have high power and good fuel economy in addition to less CO2 emissions, their market share is increasing not only in commercial vehicles, but also in passenger cars. Because of the characteristics of the diesel combustion, however, NOx is generated in localized high-temperature combustion regions, and particulates are formed in the zones of diffusion combustion. LNT and urea-SCR catalysts have been developed for the after-treatment of exhaust gas to reduce NOx in diesel vehicles. This study examined the effect of a containing promoter on SCR catalysts to cope with the severe exhaust gas regulation. The de-NOx performance of the Mn-SCR catalyst was the best, and the de-NOx performance was improved as the ion exchange rate between Mn ion and Zeolyst was good and the activation energy was low. The de-NOx performance of the 7Cu-15Ba/78Zeoyst catalyst was 32% at $200^{\circ}C$ and 30% at $500^{\circ}C$, and showed the highest performance. The NOx storage material of BaO loaded as a promoter was well dispersed in the Cu-SCR catalyst and the additional de-NOx performance of BaO was affected by the reduction reaction of the Cu-SCR catalyst. Among the three catalysts, the 7Cu-15Ba/Zeolyst SCR catalyst was resistant to thermal degradation. The same type of CuO due to thermal degradation migrates and agglomerates because BaO reduces the agglomeration of the main catalyst CuO particles.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.415-420
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• 2018

The Energy Efficiency Design Index (EEDI) introduced by the Marine Environment P rotection Committee(MEPC) in International Maritime Organization(IMO) has significantly assisted in regulating CO2 emissions. However, in adverse weather conditions, it can lead to accidents due to slow steaming of vessels and low engine propulsion power. In response to this issue, the MEPC presented guidelines for the minimum propulsion power of the main engine for maintaining the course of vessels in adverse weather conditions. However, the guidelines are only applicable for vessels with a deadweight of 20,000 tons, leaving out small and medium ships. This study evaluated vessels subject to the guidelines of minimum propulsion power and proposed revised guidelines. In addition, relevant cases of marine accidents were investigated with the aim of investigating the minimum propulsion power of main engine for medium and small ships not covered by the guidelines. In order to achieve this, engine propulsion power was analyzed according to the size of the affected vessels. The results obtained from this study could be used as a minimum power criterion that can be considered for ship building to reduce marine accidents in adverse weather for small and medium ships.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.167-175
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• 2014

This study was conducted to quantify a carbon budget of major vegetation types established in the campus of the National Institute of Ecology (NIE). Carbon budget was measured for Pinus thunbergii and Castanea crenata stands as the existing vegetation. Net Primary Productivity (NPP) was determined by applying allometric method and soil respiration was measured by EGM-4. Heterotrophic respiration was calculated as 55% of total respiration based on the existing results. Net Ecosystem Production (NEP) was determined by the difference between NPP and heterotrophic respiration (HR). NPPs of P. thunbergii and C. crenata stands were shown in $4.9ton\;C\;ha^{-1}yr^{-1}$ and $5.3ton\;C\;ha^{-1}yr^{-1}$, respectively. Heterotrophic respirations of P. thunbergii and C. crenata stands were shown in $2.4ton\;C\;ha^{-1}yr^{-1}$ and $3.5ton\;C\;ha^{-1}yr^{-1}$, respectively. NEPs of P. thunbergii and C. crenata stands were shown in $2.5ton\;C\;ha^{-1}yr^{-1}$ and $1.8ton\;C\;ha^{-1}yr^{-1}$, respectively. Carbon absorption capacity for the whole set of vegetation types established in the NIE was estimated by applying NEP indices obtained from current study and extrapolating NEP indices from existing studies. The value was shown in $147.6ton\;C\;ha^{-1}yr^{-1}$ and it was calculated as $541.2ton\;CO_2ha^{-1}yr^{-1}$ converted into $CO_2$. This function corresponds to 62% of carbon emission from energy that NIE uses for operation of various facilities including the glass domes known in Ecorium. This carbon offset capacity corresponds to about five times of them of the whole national territory of Korea and the representative rural area, Seocheongun. Considered the fact that ongoing climate change was originated from imbalance of carbon budget at the global level, it is expected that evaluation on carbon budget in the spatial dimension reflected land use pattern could provide us baseline information being required to solve fundamentally climate change problem.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.34-40
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• 2012

This research has looked into the treatment process of wood waste generated from industrial waste within the region and in order to modify the problem that may occurred during the mass balance were analyzed for development of suitable solid waste recycling network regionally. As as result, quite amount of wood waste are being transferred to another region, even though a treatment facility's capacity could bear the total amount of waste generated within the area. Although the wood waste could be treated locally, it is analyzed that amount of wood waste are being transferred due to inefficient and irrational processing system between regions. It is assumed that $CO_2$ generated and loss of unnecessary fuel cost from these inefficient system is quite a lot and in order to modify this disorganized system, it will not inevitable to treat the waste based on the characteristics of each regions. Also, the wood waste recycling system should be studied with the efficient, environmental friendly processing and delivering network by minimized transfer distance and local systemizing the waste treatment system.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.1
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• pp.52-60
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• 2000

This study was conducted to gain basic data for alleviation of gas emission and conservation of healthy soil environment by investigating an aspect of gas emission and microbial diversity due to the supplement of different fertilizers after application with a livestock manure compost in greenhouse soils. Green pepper was cultivated in clay loamy soil from April to August. Before planting, a livestock manure compost was applied with $741mg\;ha^{-1}$ on the basis of the phosphate content contained in compost. And then, deficient nitrogen for cropping was supplemented with either quick-acting fertilizer of urea or a controlled slow release fertilizer made from urea formaldehyde(U/F). $NH_3$ and R $NH_2$ gases emitted from soil showed a low concentration in the early stage but a maximum in 27 days after planting, then decreased rapidly and not detected after 33 days. Their average concentrations were 42% and 85% lower in the treatment of slow release fertilizer than that of urea fertilizer, respectively. $CO_2$ gas emitted under urea fertilization was ranged from 1,200 to $3,200mg{\ell}^{-1}$ and that in slow release fertilizer was $900{\sim}2,650mg\;{\ell}^{-1}$. The average concentration of urea treatment was $2,260mg{\ell}^{-1}$ and 30% higher than that of slow release fertilizer. The treatment of slow release fertilizer with the lapse of cropping time populated larger in numbers of bacteria, actinomycetes, nitrate bacteria and nitrate reduction bacteria, and ratios of bacteria and actinmycetes to fungi than that of urea fertilizer. But the number of fungi was higher in the treatment of urea fertilizer and denitrifying bacteria showed a similar trend in both treatments. The microbial diversity index, which calculated with numbers of 6 species of microorganisms, was decreased with increasing of growing stage in the range of 0.1 to 0.35 and that was higher in the tratment of slow release fertilizer than urea.

• Plant Journal
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• v.10 no.2
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• pp.28-37
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• 2014

Recently, it is considered that environment and energy are critical issues all over the world. In power generation sector in Korea, almost power stations are constructed and operated as cogeneration plants in conformity with this trend. KDHC(Korea District Heating Corporation) goes one step further adopting renewable energy technology like heat pump using wasted heat for energy-saving and environment improvement. This study investigates the performance characteristics by the location of waste heat recovery heat pumps of 5 Gcal/h capacity in 150 MW-class Gwang-gyo cogeneration plant using commercial software 'THERMOFLEX'. Prior to analysis, the simulations are performed with actual operation data, and then the validation of simulations is verified by checking the error within 2%. After verification, the simulations are carried out with 3 locations and the effect on electrical power output and heat output is analyzed. As a result, overall efficiency of cogeneration plant is the highest in the case of heat pump located before DH(District Heating) Heater because of the largest increase of heat output despite of decrease of electrical power output.