• Journal of Environmental Impact Assessment
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• v.27 no.2
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• pp.124-138
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• 2018

This research was conducted to examine the availability of spatial data for assessing absorption rates of $CO_2$ in the forest of Ansan-si and evaluate the validity of methods that analyze $CO_2$ absorption. To statistically assess the $CO_2$ absorption rates per year, the 1:5,000 Digital Forest-Map (Lim5000) and Standard Carbon Removal of Major Forest Species (SCRMF) methods were employed. Furthermore, Land Cover Map (LCM) was also used to verify $CO_2$ absorption rate availability per year. Great variations in $CO_2$ absorption rates occurred before and after the year 2010. This was due to improvement in precision and accuracy of the Forest Basic Statistics (FBS) in 2010, which resulted in rapid increase in growing stock. Thus, calibration of data prior to 2010 is necessary, based on recent FBS standards. Previous studies that employed Lim5000 and FBS (2015, 2010) did not take into account the $CO_2$ absorption rates of different tree species, and the combination of SCRMF and Lim5000 resulted in $CO_2$ absorption of 42,369 ton. In contrast to the combination of SCRMF and Lim5000, LCM and SCRMF resulted in $CO_2$ absorption of 40,696 ton. Homoscedasticity tests for Lim5000 and LCM resulted in p-value <0.01, with a difference in $CO_2$ absorption of 1,673 ton. Given that $CO_2$ absorption in forests is an important factor that reduces greenhouse gas emissions, the findings of this study should provide fundamental information for supporting a wide range of decision-making processes for land use and management.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.304-311
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• 1999

This experiment was conducted to find out the optimum condition of aeration rates for removal of malodor and to improve the compost quality. The aspect of ammonia emission and amounts of volatilization were investigated in the enclosed composting reactor of 242 liters piled with mixed materials of dairy manure and rice straw, which adjusted to 65% of initial moisture content and controlled by four different aeration rates. Mature temperature increased suddenly in initial composting time and decreased with Increasing aeration rates. The treatment of $1.79l\;min^{-1}kg\;dry-solids^{-1}$ results in overcooling and rapid drying of composting materials because of too much aeration. The average concentration of ammonia emitted from composting for 24 days was the range of 25.3 to $239.8mg\;l^{-1}$ and was highest in the treatment of $0.09l\;min^{-1}kg\;dry-solids^{-1}$, followed by 0.90. 0.18 and $1.79l\;min^{-1}kg\;dry-solids^{-1}$. The range of maximum concentration by different aeration rates was $335{\sim}2279mg\;l^{-1}$ and it wan highest in the treatment of $0.09l\;min^{-1}kg\;dry-solids^{-1}$, followed by 0.18, 0.09 and $1.79l\;min^{-1}kg\;dry-solids^{-1}$. Relationship between the ammonia concentration emitted and temperature matured under different aeration rates showed an exponential positive correlation with 1% significance and had a trend of clear increase in ammonia concentration with increasing temperature over $50^{\circ}C$. Most of ammonia volatilized within plays after composting. The volatilization rate of ammonia ranged from 0.056 to 0.453 per dry solids of materials and it was highest in the treatment of $0.09l\;min^{-1}kg\;dry-solids^{-1}$, followed by 0.18, 0.09 and $1.79l\;min^{-1}kg\;dry-solids^{-1}$. Amounts of ammonia volatilized under composting condition of this experiment was estimated to be highest in the aeration range of 0.9 to $1.0l\;min^{-1}kg\;dry-solids^{-1}$.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.705-715
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• 2010

The adoption of carbon foot print system is being activated mostly in the developed countries as one of the long-term response towards tightened up regulations and standards on carbon emission in the agricultural sector. The Korean Ministry of Environment excluded the primary agricultural products from the carbon foot print system due to lack of LCI (life cycle inventory) database in agriculture. Therefore, the research on and establishment of LCI database in the agriculture for adoption of carbon foot print system is urgent. Development of LCA (life cycle assessment) methodology for application of LCA to agricultural environment in Korea is also very important. Application of LCA methodology to agricultural environment in Korea is an early stage. Therefore, this study was carried out to find out the effect of lettuce cultivation on agricultural environment by establishing LCA methodology. Data collection of agricultural input and output for establishing LCI was carried out by collecting statistical data and documents on income from agro and livestock products prepared by RDA. LCA methodology for agriculture was reviewed by investigating LCA methodology and LCA applications of foreign countries. Results based on 1 kg of lettuce production showed that inputs including N, P, organic fertilizers, compound fertilizers and crop protectants were the main sources of major emission factor during lettuce cropping process. The amount of inputs considering the amount of active ingredients was required to estimate the actual quantity of the inputs used. Major emissions due to agricultural activities were $N_2O$ (emission to air) and ${NO_3}^-$/${PO_4}^-$ (emission to water) from fertilizers, organic compounds from pesticides and air pollutants from fossil fuel combustion in using agricultural machines. The softwares for LCIA (life cycle impact assessment) and LCA used in Korea are 'PASS' and 'TOTAL' which have been developed by the Ministry of Knowledge Economy and the Ministry of Environment. However, the models used for the softwares are the ones developed in foreign countries. In the future, development of models and optimization of factors for characterization, normalization and weighting suitable to Korean agricultural environment need to be done for more precise LCA analysis in the agricultural area.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.393-398
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• 2008

Several researchers have proposed models or equations to predict soil $CO_2$ flux from more readily available biotic and abiotic measurement. Tree commonly used abiotic variables were N mineral and soil temperature and soil water content. This study was conducted to determine $CO_2$ emission to mineral N, soil water content and soil temperature with clay loam and sandy loam in pepper cultivation in 2004~2005. $CO_2$ flux in the upland with different levels of soil water potential was measured at least once in two weeks during the cropping period in the pepper cultivation plots. Soil water potential in the clay loam and sandy loam soils was established at -30kPa and -50kPa by measuring the soil gravimetric water content with two replications. $CO_2$ emission rate from the differently managed plots was highly correlation coefficient to between the mineral N ($R=0.830^{**}$, $0.876^{**}$) and soil temperature ($r^2=0.793^{**}$, $0.804^{**}$) in the clay loam and sandy loam, respectively. However, the relationships between $CO_2$ emission and soil water content were non-significant. $CO_2$ emissions at sandy loam soils was lower to 21~37% than at clay loam soils for both soil water conditions without differences in yield. At difference levels of soil water conditions, $CO_2$ emission at -50kPa decreased to 37.5% in comparison with that at -30kPa. From the path analysis as to contribution factors of GHGs, it appeared that contribution rate was in the order of soil temperature (54.9%), mineral N (32.7%), and soil moisture content (12.4%).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.65-74
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• 2016

This study mainly focuses on urban regeneration project as a countermeasure to resolve climate change issues by analyzing the carbon-reduction effect of Jeonju test-bed cases. First, an urban regeneration project is designed for city, Jeonju by analyzing its environmental problems and potential improvement. Then, carbon emission and reduction amounts are evaluated for different businesses and scenarios. Carbon emission sources are classified according to a standard suggested by IPCC, and the emissions are calculated by various standard methods. The result shows that carbon emission amount in Jeonju test-bed is 102,149 tCO2eq. The fact that 70% of the emission from energy sector originates from buildings implies that urban regeneration projects can concentrate on building portions to effectively reduce carbon emission. It is also projected carbon emission will decrease by 3,826tCo2eq in 2020 compared to 2011, reduction mainly based on overall population and industry shrinkage. When urban regeneration projects are applied to 5 urban sectors (urban environment, land use, green transportation, low carbon energy, and green buildings) total of 10,628tCO2eq is reduced and 4,857tCO2 (=15.47%) when only applied to the green building sector. Moreover, different carbon reduction scenarios are set up to meet each goal of different sectors. The result shows that scenario A, B, and C each has 5%, 11%, and 15% of carbon reduction, respectively. It is recommended to apply scenario B to achieve 11% reduction goal in a long term. Therefore, this research can be a valuable guideline for planning future urban regeneration projects and relative policies by analyzing the present urban issues and suggesting improvement directions.

• Progress in Medical Physics
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• v.20 no.2
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• pp.72-79
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• 2009

Scatter correction for I-131 plays a very important role to improve image quality and quantitation. I-131 has multiple and higher energy gamma-ray emissions. Image quality and quantitative accuracy in I-131 imaging are degraded by object scatter as well as scatter and septal penetration in the collimator. The purpose of this study was to estimate scatter and septal penetration and investigate two scatter correction methods using Monte Carlo simulation. The gamma camera system simulated in this study was a FORTE system (Phillips, Nederland) with high energy, general-purpose, parallel hole collimator. We simulated for two types of high energy collimators. One is composed of lead, and the other is composed of artificially high Z number and high density. We simulated energy spectrum using a point source in air. We estimated both full width at half maximum (FWHM) and full width at tenth maximum (FWTM) using line spread function (LSF) in cylindrical water phantom. We applied two scatter correction methods, triple energy window scatter correction (TEW) and extended triple energy window scatter correction (ETEW). The TEW method is a pixel-by pixel based correction which is easy to implement clinically. The ETEW is a modification of the TEW which corrects for scatter by using abutted scatter rejection window, which can overestimate or the underestimate scatter. The both FWHM and FWTM were estimated as 41.2 mm and 206.5 mm for lead collimator, respectively. The FWHM and FWTM were estimated as 27.3 mm and 45.6 mm for artificially high Z and high density collimator, respectively. ETEW showed that the estimation of scatter components was close to the true scatter components. In conclusion, correction for septal penetration and scatter is important to improve image quality and quantitative accuracy in I-131 imaging. The ETEW method in scatter correction appeared to be useful in I-131 imaging.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1157-1163
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• 2012

This study was performed a comparative life cycle assessment (LCA) among three rice production systems in order to analyze the difference of greenhouse gases (GHGs) emissions and environment impacts. Its life cycle inventory (LCI) database (DB) was established using data obtained from interview with conventional, without agricultural chemical and organic farming at Gunsan and Iksan, Jeonbuk province in 2011. According to the result of LCI analysis, $CO_2$ was mostly emitted from fertilizer production process and rice cropping phase. $CH_4$ and $N_2O$ were almost emitted from rice cultivation phase. The value of carbon footprint to produce 1 kg rice (unhulled) on conventional rice production system was 1.01E+00 kg $CO_2$-eq. $kg^{-1}$ and it was the highest value among three rice production systems. The value of carbon footprints on without agricultural chemical and organic rice production systems were 5.37E-01 $CO_2$-eq. $kg^{-1}$ and 6.58E-01 $CO_2$-eq. $kg^{-1}$, respectively. Without agricultural chemical rice production system whose input amount was the smallest had the lowest value of carbon footprint. Although the yield of rice from organic farming was the lowest, its value of carbon footprint less than that of conventional farming. Because there is no compound fertilizer inputs in organic farming. Compound fertilizer production and methane emission during rice cultivation were the main factor to GHGs emission in conventional and without agricultural chemical rice production systems. In organic rice production system, the main factors to GHGs emission were using fossil fuel on machine operation and methane emission from rice paddy field.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.34-45
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• 2016

Global warming and climate change have been caused by combustion of fossil fuels. The greenhouse gases contributed to the rise of temperature between $0.6^{\circ}C$ and $0.9^{\circ}C$ over the past century. Presently, fossil fuels account for about 88% of the commercial energy sources used. In developing countries, fossil fuels are a very attractive energy source because they are available and relatively inexpensive. The environmental problems with fossil fuels have been aggravating stress from already existing factors including acid deposition, urban air pollution, and climate change. In order to control greenhouse gas emissions, particularly CO2, fossil fuels must be replaced by eco-friendly fuels such as biomass. The use of renewable energy sources is becoming increasingly necessary. The biomass resources are the most common form of renewable energy. The conversion of biomass into energy can be achieved in a number of ways. The most common form of converted biomass is pellet fuels as biofuels made from compressed organic matter or biomass. Pellets from lignocellulosic biomass has compared to conventional fuels with a relatively low bulk and energy density and a low degree of homogeneity. Thermal pretreatment technology like torrefaction is applied to improve fuel efficiency of lignocellulosic biomass, i.e., less moisture and oxygen in the product, preferrable grinding properties, storage properties, etc.. During torrefacton, lignocelluosic biomass such as palm kernell shell (PKS) and empty fruit bunch (EFB) was roasted under an oxygen-depleted enviroment at temperature between 200 and $300^{\circ}C$. Low degree of thermal treatment led to the removal of moisture and low molecular volatile matters with low O/C and H/C elemental ratios. The mechanical characteristics of torrefied biomass have also been altered to a brittle and partly hydrophobic materials. Unfortunately, it was much harder to form pellets from torrefied PKS and EFB due to thermal degradation of lignin as a natural binder during torrefaction compared to non-torrefied ones. For easy pelletization of biomass with torrefaction, pellets from PKS and EFB were manufactured before torrefaction, and thereafter they were torrefied at different temperature. Even after torrefaction of pellets from PKS and EFB, their appearance was well preserved with better fuel efficiency than non-torrefied ones. The physical properties of the torrefied pellets largely depended on the torrefaction condition such as reaction time and reaction temperature. Temperature over $250^{\circ}C$ during torrefaction gave a significant impact on the fuel properties of the pellets. In particular, torrefied EFB pellets displayed much faster development of the fuel properties than did torrefied PKS pellets. During torrefaction, extensive carbonization with the increase of fixed carbons, the behavior of thermal degradation of torrefied biomass became significantly different according to the increase of torrefaction temperature. In conclusion, pelletization of PKS and EFB before torrefaction made it much easier to proceed with torrefaction of pellets from PKS and EFB, leading to excellent eco-friendly fuels.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.174-182
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• 2011

The present study evaluated the major lead sources in a steel metallurgy industrialized city by measuring lead isotopes/lead concentrations of ambient air and potential sources in an industrial area and residential areas according to relative distance. The quality control program obtained during the measurement procedure for lead isotopes and concentrations exhibited $0.5ng/m^3$ for method detection limit, more than 90% for recoveries of standard particulate matters, and lower than 0.2% for reproducibility errors of four lead isotopes ($^{204}Pb$, $^{206}Pb$, $^{207}Pb$, $^{208}Pb$). For all three lead isotope ratios ($^{206}Pb/^{204}Pb$, $^{207}Pb/^{206}Pb$, $^{208}Pb/^{206}Pb$), the ratios were obtained in the industrial area were closer to nearby residential area than those of a residential area far away from the industrial area, thereby suggesting that lead sources were more similar each other in the industrial and nearby residential area. Furthermore, for both summer and winter seasons ambient lead concentrations were more than four times higher in the industrial area than in the residential areas and in turn, they were higher in the nearby residential area compared with the far-away residential area. As a result, it was suggested that lead emitted from the industrial area would influence more the ambient lead in the nearby residential area than the far-away residential area. Both slag and traffic emissions are likely to be major lead sources in the industrial and nearby residential areas, since their three lead isotope ratios ($^{206}Pb/^{204}Pb$, $^{207}Pb/^{206}Pb$, $^{208}Pb/^{206}Pb$) were similar to the ratios obtained from ambient air of these two areas. In addition, the lead isotope ratios revealed different pattern between seasons, and the ambient lead concentrations were higher for winter than for summer.

• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.131-141
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• 1994

To investigate differences in Cd and Zn contents in paddy soils and rice plants polluted by aerial emissions from the Janghang smelter, soil samples in the different directions and at the surface (0-15cm) and subsurface (15-30cm) in 1982 and 1990, and rice plants at the corresponding sampling sites in 1990 were collected from the Janghang Smelter Area. Soil samples were extracted with $4M-HNO_3$ and plant samples were digested with a mixture of $HNO_3$ and $HClO_4$for analyzing by atomic absorption spectrophotometry. The Cd and Zn contents in soils ranged from 0.09 to 4.42 and from 16.0 to 959.5mg $kg^{-1}$, respectively. The average contents of Cd and Zn in 1990 were higher than those in 1982. The Cd and Zn contents of soils near the center of the smelter were higher than those of soils farther from the center and also decreased in the order of east > north-north east > north east > north. The Cd and Zn levels in surface soils were higher than those in subsurface soils. The contaminated areas of Cd and Zn were within 4km in the east, and within 3km in the north-north east and the north east. Metal contents in brawn rice were the lowest in rice plants. The Cd content of brown rice was one sixth of that in leaf blade and in leaf sheath. The Cd content of leaf blade, stem and panicle axis were significantly correlated with the levels of Zn, Cu and Pb in soils, and Zn content of stem was significantly correlated with the levels of Cu and Pb. The Cd and Zn content in brown rice ranged from 0.05 to 0.25mg $kg^{-1}$ and from 10.5 to 30.9㎎ $kg^{-1}$ in the smelter area, respectively.