• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.328-333
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• 2006

A few methodologies have been recently developed to estimate the environmental affect when various materials and components are used in building life cycle. The direct survey method has limitations to analyze the environmental problems because of the limit of survey scope and cost. Therefore, another indirect method has been developed as alternatives. The indirect method is represented as input-output analysis. This paper aimed at analyzing the estimation the environmental affect of building materials and works at building construction, utilizing the input-output analysis as a indirect estimation method. The results suggested that the building works is overally responsible for the energy consumption and $CO_2$ emission. In other words, Over the 80% of the total consumption and $CO_2$ emission are resulted at the building work.

• Journal of Hydrogen and New Energy
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• v.17 no.1
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• pp.109-116
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• 2006

The heat treatment characteristics of natural talc sample was investigated in diverse analytical view point. The mass decrease comes to heat treatment was resulted by the continuous and the discontinuous process and the obtained result show very similar two step profiles with 8.9 % mass decrease. The dehydroxylation of -OH groups contained talc crystal was analyzed by spectroscopic method and the crystallographic variations was also observed after heat treatment. According to XPS result, the magnesium hydroxide($Mg(OH)_2$) of untreated talc powder changed to magnesium oxides(MgO) after heat treatment.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.1
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• pp.38-45
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• 2002

This study was conducted to determine the smoke component concentration and the smoke distribution in the cambridge filter pad and cigarette filter with stalk position and grade of Korean leaf tobaccos. 12 grades of flue-cured and burley leaf tobaccos which were taken from the Kim-cheon and Ock-cheon leaf tobacco processing factory were used for this study. Six kinds of smoke components such as tar, nicotine, water, carbon monoxide(CO), carbon dioxide($CO_2$) puff No. collected in the cambridge filter pad and cigarette filter were analyzed. Also, nicotine/tar, CO/tar ratio were calculated from the analytical data. Puff no., CO, and $CO_2$ concentration of flue-cured and burley tobacco leaves at high stalk position were higher than those of low stalk position, and these components were increased in high grade of leaf tobacco. Compared with flue-cured tobacco, burley tobacco showed a little values of puff no., nicotine, and tar concentration. The pH range of burley tobaccos was broader than that of flue-cured tobaccos, and the ammonia concentration of burley tobaccos was significantly higher than that of flue-cured tobaccos. The pH value and ammonia concentration of burley tobaccos were decreased as stalk position of leaf tobaccos decreased. The distribution of smoke components collected in the cambridge filter pad and cigarette filter was different with a different grade and stalk position of tobacco leaves. In high stalk position of tobacco leaves, the portion of smoke components collected in the cambridge filter pad was also increased. The average nicotine, water, and tar removal efficiency by a cigarette filter in a flue-cured tobacco were 37%, 64%, and 48%, respectively. Compared with flue-cured tobaccos, smoke components of burley tobaccos had high nicotine and low water removal efficiency by a cigarette filter. The average ratio of nicotine/tar and CO/tar of flue-cured tobaccos and burley tobaccos were 0.097, 1.22, 0.094, and 0.97, in order. Nicotine/tar ratio was decreased and CO/tar ratio was increased in low stalk position.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1484-1490
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• 2009

Since the cooling performance of a $CO_2$ cooling cycle is varied significantly with a variation of refrigerant charge amount and outdoor temperature, the reliability of $CO_2$ system is down. In this study, the performance characteristics of three kinds of $CO_2$ systems were measured and analyzed by varying refrigerant charge amount and outdoor temperature so as to study the characteristics of variation with cycle option. The applied system options are the single-stage compression(1C-1E) system, two-stage compression with 1-EEV(2C-1E) system, and two-stage compression with 2-EEV(2C-2E) system. The performances of two-stage compression with 2-EEV system were less sensitive than those of other systems and the system operated safely and steadily for wide charge amount. The performance of the two-stage compression with 1-EEV(2C-1E) system was the most sensitive to the charge amount, and that of the single-stage compression(1C-1E) system varied a lot with outdoor temperature.

• Journal of the Korean earth science society
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• v.35 no.3
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• pp.192-202
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• 2014

The purpose of this study was to investigate high school students' conception of conservation of mass through the scenario of carbon emission in terms of carbon cycle. Seventy six high school students of 11th grade were participated in this study. Participants were provided with two scenarios that showed a gradual increase and decrease of atmospheric $CO_2$ amount from the level recorded in 2013 up to 450 ppm and to 340 ppm by 2110, which is the changes of around 15%. We asked participants to explain the reason after having them draw the emissions trajectory of $CO_2$ according to scenario. Most participants thought that carbon emission would continue to increase despite the two scenarios of carbon emission making sense in terms of conservation of mass between emissions and the natural removal of carbon dioxide. This implies that participants came to think of pattern matching that carbon emission would continue to increase as they used correlation graphs of carbon emission: that is, the graphs of the evolution of anthropogenic emissions, of atmospheric $CO_2$, and of global mean temperature, from the beginning of the Industrial Revolution up to date, all of which are shown in high school earth science textbooks.

• Journal of the Mineralogical Society of Korea
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• v.30 no.4
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• pp.205-217
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• 2017

Mineral carbonation by indirect method has been studied by serpentinite as cation source. Through the carbonation of $CO_2$ and alkaline earth ions (calcium and magnesium) from serpentinite, the pure carbonates including $MgCO_3$ and $CaCO_3$ were synthesized. The extraction solvent used to extract magnesium (Mg) was ammonium sulfate ($(NH_4)_2SO_4$), and the investigated experimental factors were the concentration of $(NH_4)_2SO_4$, reaction temperature, and ratio of serpentinite to the extraction solvent. From this study, the Mg extraction efficiency of approximately 80 wt% was obtained under the conditions of 2 M $(NH_4)_2SO_4$, $300^{\circ}C$, and a ratio of 5 g of serpentinite/75 mL of extraction solvent. The Mg extraction efficiency was proportional to the concentration and reaction temperature. $NH_3$ produced from the Mg extraction of serpentinite was used as a pH swing agent for carbonation to increase the pH value. About 1.78 M of $NH_3$ as the form of $NH_4{^+}$ was recovered after Mg extraction from serpentinite. And, the main step in Mg extraction process of serpentinite was estimated by geochemical modeling.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.141-150
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• 2022

To abate the environmental burden derived from the massive generation of cattle manure (CM), pyrolysis of CM was suggested as one of the methods for manure treatment. In respect of carbon utilization, pyrolysis has an advantage in that it can produce usable carbon-based chemicals. This study was conducted to investigate a syngas production from pyrolysis of CM in CO₂ condition. In addition, mechanistic functionality of CO₂ in CM pyrolysis was investigated. It was found that the formation of CO was enhanced at ≥ 600 ℃ in CO2 environment, which was attribute to the homogeneous reactions between CO₂ and volatile matters (VMs). To expedite reaction kinetics for syngas production during CM pyrolysis, Catalytic pyrolysis was carried out using Co/SiO2 as a catalyst. The synergistic effects of CO₂ and catalyst accelerate the formation of H₂ and CO at entire temperature range. Thus, this result offers that CO₂ could be a viable option for syngas production with the mitigation of greenhouse gas.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.4
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• pp.234-240
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• 2010

In October 2009, the Ministry of Land Transport and Maritime Affairs noticed 'Environment-friendly housing construction standards and performance' to build energy saving environment-friendly housings (Green Homes) for the reduction of energy consumption and carbon dioxide emission. In this study, the $CO_2$ emissions were evaluated during the life cycle of the existing apartments which were built in 1980's and Green Home apartment. $LCCO_2$ was evaluated by dividing the life cycle into three stages which are construction, maintenance and destruction stage. $CO_2$ emission from the materials for improving insulation performance was estimated by Input-output analysis. As a result, in 40 year-life cycle of $84\;m^2$ apartment, 400.68 T-$CO_2$ was emitted from 1980's apartment, on the other hand 231.02 T-$CO_2$ was emitted from Green Home apartment.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.712-717
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• 2015

In this study, the experiment of CO production was performed using carbon dioxide and coal. The synthesis characteristics of CO gas was investigated using the chemical activation method of KOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to coal ratio, the flow rate of gas and reaction temperature during $CO_2$ conversion reaction. Without the catalyst of KOH, the 66.7% of $CO_2$ conversion was obtained at the conditions of $T=950^{\circ}C$ and $CO_2$ flow rate of 300 cc/min. On the other hand, the 98.1% of $CO_2$ conversion was obtained using catalyst of KOH at same conditions. It was found that the feed ratio(Coal : KOH = 4 : 1) had better $CO_2$ conversion and CO selectivity than other feed ratios.

• Membrane and Water Treatment
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• v.8 no.2
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• pp.171-184
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• 2017

This study presents the effect of hydraulic retention time (HRT) on the characteristics of emission of three major greenhouse gases (GHGs) including $CH_4$, $CO_2$ and $N_2O$ during operation of a sequencing batch reactor for aerobic oxidation of methane with denitrification (AeOM-D SBR). Dissolved $N_2O$ concentration increased, leveled-off and slightly decreased as the HRT increased from 0.25 to 1d. Concentration of the dissolved $N_2O$ was higher at the shorter HRT, which was highly associated with the lowered C/N ratio. A longer HRT resulted in a higher C/N ratio with a sufficient carbon source produced by methanotrophs via methane oxidation, which provided a favorable condition for reducing $N_2O$ formation. With a less formation of the dissolved $N_2O$, $N_2O$ emission rate was lower at a longer HRT condition due to the lower C/N ratio. Opposite to the $N_2O$ emission, emission rates of $CH_4$ and $CO_2$ were higher at a longer HRT. Longer HRT resulted in the greater total GHGs emission as $CO_2$ equivalent which was doubled when the HRT increased from 0.5d to 1.0 d. Contribution of $CH_4$ onto the total GHGs emission was most dominant accounting for 98 - 99% compared to that of $N_2O$ (< 2%).