• Journal of Environmental Health Sciences
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• v.36 no.2
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• pp.128-135
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• 2010

The main purpose of this study was to develop the greenhouse gas emission factor for power plant using sub-bituminous coal. In Korea, Fired power plant are a major source of greenhouse gases within the fossil fuel combustion sectors, thus the development of emission factors is necessary to understand the characteristics of the national specific greenhouse gas emission and to develop nation specific emission factors. These emission factors were derived from the $CO_2$ concentrations measurement from stack and fuel analysis of sub-bituminous coal. Caloric value of sub-bituminous coal used in the power plants were 5,264 (as received basis), 5,936 (air-dried basis) and 6,575 kcal/kg (dry basis). The C emission factors by fuel analysis and $CO_2$ concentration measurement was estimated to be 26.7(${\pm}0.9$), 26.3(${\pm}2.8$)tC/MJ, respectively. Our estimates of C emission factors were comparable with IPCC default value.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.57-68
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• 2023

In this study, coffee waste was recycled into nitrogen-doped porous carbon fibers as an active material for high-energy EDLC (Electric Double Layer Capacitors). The coffee waste was mixed with polyvinylpyrrolidone and dissolved into dimethylformamide. The mixture was then electrospun to fabricate coffee waste-derived nanofibers (Bare-CWNF), and carbonization process was followed under a nitrogen atmosphere at 900℃. Similar to Bare-CWNF, the as-synthesized carbonized coffee waste-derived nanofibers (Carbonized-CWNF) maintained its fibrous form while preserving the composition of nitrogen. The electrochemical performance was analyzed for carbonized coffee waste (Carbonized-CW)-, carbonized PAN-derived nanofibers (Carbonized-PNF)-, and Carbonized-CWNF-based electrodes in the operating voltage window of -1.0-0.0V, Among the electrodes, Carbonized-CWNF-based electrodes exhibited the highest specific capacitance of 123.8F g^-1 at 1A g^-1 owing to presence of nitrogen and porous structure. As a result, nitrogen-contained porous carbon fibers synthesized from coffee waste showed excellent electrochemical performance as electrodes for high-energy EDLC. The experimental designed in this study successfully demonstrated the recycling of the coffee waste, one of the plant-based biomass that causes the environmental pollution into high-energy materials, also, attaining the ecofriendliness.

• Clean Technology
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• v.23 no.4
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• pp.441-447
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• 2017

The economic analysis for the power plant developed in the conceptual design phase is becoming more important and, research on process optimization for process development that meets the target economic is actively carried out. In the filed of power generation systems, economic assessment methods to predict the levelized cost of electricity (LCOE) has been widely applied for comparing economic effect quantitatively. In this paper, the platform that design criteria of key component required to optimize economic of power cycle can be calculated reversely was established roughly and design criteria of the key equipment (Compressor, turbine, heat exchanger) required to meet the target LCOE (the LCOE of supercritical steam Rankine cycle) was derived when the supercritical $CO_2$ power cycle is applied to the coal-fired power plant.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.603-615
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• 2022

Soybean (Glycine max (L) Merr.) provides plant-derived proteins, soy vegetable oils, and various beneficial metabolites to humans and livestock. The importance of soybean is highly underlined, especially when carbon-negative sustainable agriculture is noticeable. However, many diseases by pests and pathogens threaten sustainable soybean production. Therefore, understanding molecular interaction between diverse cultivated varieties and pathogens is essential to developing disease-resistant soybean plants. Here, we established a pathosystem of the Korean domestic cultivar Kwangan against Pseudomonas syringae pv. syringae B728a. This bacterial strain caused apparent disease symptoms and grew well in trifoliate leaves of soybean plants. To examine the disease susceptibility of the cultivar, we analyzed transcriptional changes in soybean leaves on day 5 after P. syringae pv. syringae B728a infection. About 8,900 and 7,780 differentially expressed genes (DEGs) were identified in this study, and significant proportions of DEGs were engaged in various primary and secondary metabolisms. On the other hand, soybean orthologs to well-known plant immune-related genes, especially in plant hormone signal transduction, mitogen-activated protein kinase signaling, and plant-pathogen interaction, were mainly reduced in transcript levels at 5 days post inoculation. These findings present the feature of the compatible interaction between cultivar Kwangan and P. syringae pv. syringae B728a, as a hemibiotroph, at the late infection phase. Collectively, we propose that P. syringae pv. syringae B728a successfully inhibits plant immune response in susceptible plants and deregulates host metabolic processes for their colonization and proliferation, whereas host plants employ diverse metabolites to protect themselves against infection with the hemibiotrophic pathogen at the late infection phase.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.138-144
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• 2008

The production of the entomopathogenic and phytotoxic cyclic depsipeptide beauvericin (BEA) was studied in submerged cultures of Fusarium oxysporum KFCC 11363P isolated in Korea. The influences of various factors on mycelia growth and BEA production were examined in both complete and chemically defined culture media. The mycelia growth and BEA production were highest in Fusarium defined medium. The optimal carbon and nitrogen sources for maximizing BEA production were glucose and $NaNO_3$, respectively. The carbon/nitrogen ratio for maximal production of BEA was investigated using response surface methodology (RSM). Equations derived by differentiation of the RSM model revealed that the production of BEA was maximal when using 108 mM glucose and 25 mM $NaNO_3$.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1065-1073
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• 2006

The unturned carbon in fly ash, recently occurred in the coal-fired Yong Hung power station, caused some problems in ash utilization and boiler efficiency. This paper describes the analysis of unburned carbon and six coals, some tests performed at Yong Hung Boiler, and the results of combustion modification for the reduction of unburned carbon in fly ash. From the physical and chemical analysis of unburned carbon in fly ash, most particles were turned out to be hollow cenosphere and agglomerated soot particles. The sooting potential from six coals used in the plant were investigated with CPD(Chemical Percolation Devolatilization) model. The results showed that the higher potential was presented to Peabody, Arthur, Shenhua coals rather than other coals. It was necessary to measure the coal flow rates at each coal feeding pipe for four burner levels since they affect the extent of mixing of soot with oxidant, in turn, the oxidation rate of soot particles. The unbalance in coal flow rate was found in several coal pipes. We successfully reduced unturned carbon in ash by increasing the excess air and changing the SOFA's yaw angle.

• Korean Journal of Environmental Agriculture
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• v.40 no.3
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• pp.161-168
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• 2021

BACKGROUND: Biochar has ability to reduce N loss, increase crop yield, and sequestrate carbon in the soil However, there is still limited study concerning the interactive effects of various biochars on NH₃ loss and plant growth. This study, therefore, was conducted to investigate the NH₄⁺ adsorption characteristics of biochar derived from rice and maize residues. METHODS AND RESULTS: By-products were pyrolyzed under oxygen-limited conditions at 300-700℃ for 1 hour and used for experiment of NH₄⁺ adsorption in aqueous solution. The adsorption characteristics of biochar were studied using Langmuir isotherm. Biochar yield and hydrogen content decreased with increasing pyrolysis temperatures, whereas pH, EC, and total carbon content increased. The biochar pyrolyzed at lower temperatures was more efficient at NH₄⁺ adsorption than those produced at higher temperatures. In addition, the R_L values, indicating equilibrium coefficient were between 0 and 1, confirming that the result was suitable for Langmuir isotherm. CONCLUSION: The maize stalk biochar pyrolyzed at 300℃ was the most efficient to adsorb NH₄⁺ from the aqueous solution. Furthermore, the adsorption results of this experiment were lower than those of other prior studies, which were ascribed to different experimental conditions such as ingredients, and pyrolysis conditions.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.731-743
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• 2018

In bio-jet fuel production, selecting operating conditions of hydro-upgrading is of great importance to make iso-Paraffin rich hydrocarbons with carbon distribution including jet fuel range. Herein, iso-Paraffin rich biofuel including jet fuel range hydrocarbons ($C_8-C_{16}$) is produced from simultaneous cracking and isomerization using n-Paraffin rich hydrocarbon derived from hydrotreated vegetable oil over 0.5 wt..% Pt/Zeolite catalyst. We report and analyze the yields and compositions in the produced hydrocarbons affected by various operating conditions, such as reaction temperature, reaction pressure, molar ratio of reactants, and weight hourly space velocity. Aforementioned operating conditions not only can help interpret the reaction dynamics of hydro-upgrading, but also further produce bio jet-fuel after distillation.

• Journal of the korean society of oceanography
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• v.35 no.1
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• pp.56-64
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• 2000

The importance of terrestrial organic matter as a food source for a brackish water clam Corbicula japonica was evaluated using stable carbon isotope ratios (${\delta}^{13}$C) in its tissues and potential food resources in an estuarine system of Youngil Bay, Korea. Suspended particulate organic matter (POM) had distinct ${\delta}^{13}$C values from riverine (-31.8 to -27.2%$_o$) to marine waters (-21.0 to -16.6%$_o$). Estuarine macroalgae had a wide ${\delta}^{13}$C range of -22.8 to -15.0%$_o$. The ${\delta}^{13}$C values of riverine POM were more negative than that of riverine phytoplankton (-26.5 to -24.2%$_o$) but similar to that of freshmarsh plant species (-29.1 to -27.5%$_o$ for Phragmites communis and -28.5 to -27.0%$_o$ for Salix gracilistyla), These ${\delta}^{13}$C values suggest that the POM transported by the Hyungsan River is predominantly of terrestrial origin rather than riverine autochthonous sources. The ${\delta}^{13}$C values of Corbicula japonica tissues (-28.7 to -27.2%$_o$) were most similar to values for riverine POM and freshmarsh plants. There was no significant difference in the isotopic composition of the clam individuals. The results indicate a predominant contribution of organic carbon derived from terrestrial and fresmarsh plant detritus to the diet of Corbicula japonica. Our results also confirm previous suggestion that terrestrial organic matter can be incorporated into estuarine food webs although its role is confined to the upper estuarine reaches.

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.188-194
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• 2023

This study aimed to derive the basic wood density, one of several carbon emission factors, for carbon accounting of bamboo forests in Korea. Bamboo is mainly distributed in Jeollanam-do and Gyeongsangnam-do provinces, and 101 sample trees were selected for each of the three species (Phyllostachys nigra var. henonis, P. bambusoides, and P. pubescens). The basic wood density derivation used the KS F 2098 method. The measurements showed that the basic wood density was 0.83 g/cm³ for P. nigra var. henonis, 0.81 g/cm³ for P. bambusoides, and 0.72 g/cm³ for P. pubescens. However, the bamboo distribution area in Korea is not very large, and P. pubescens grows in one area only. Therefore, the basic wood density that can be applied to bamboo was 0.79 g/cm³. Evaluation of the uncertainty of the extracted basic wood density showed a very low value of 1.61%, which confirmed the reliability of the basic wood density derived from this analysis. The basic wood density, biomass expansion factor, and root-to-shoot ratio were used to calculate the carbon storage capacity of one bamboo plant and expanded to calculate the capacity for a hectare of bamboo. Carbon storage and absorption of bamboo were calculated by applying a carbon-emission factor, such as the basic wood density. These study results are expected to contribute to the carbon-neutral policy and forest management direction in Korea.