• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.3
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• pp.149-157
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• 2018

Low density polyethylene (LDPE) has been researched in many industrial applications, and LDPE/zeolite 4A composites has been extensively studied for many applications such as microporous, breathable film and so on. LDPE/zeolite composite have a great potential for carbon dioxide adsorption film due to its high adsorption ability. In this study, LDPE/zeolite 4A composites with various contents were prepared by melt mixing process, and co-extrusion process was applied to develop a $CO_2$ adsorption conventional film and foamed film. The thermal, rheological, mechanical, physical and morphological properties of composite films has been characterized, and $CO_2$ adsorption of the composite films evaluated by thermogravimetric analysis (TGA) and the performance was found to be about 18 cc/g at 30.9 wt% of the zeolite content.

• Natural Product Sciences
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• v.5 no.2
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• pp.75-79
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• 1999

Supercritical carbon dioxide was used as a solvent in the extraction of freeze-dried Pandanus odorus leaves. Analysis of the extract with GC-MS showed that Pandanus odorus leaves contain nutritional constituents such as ${\alpha}-tocopherol$ (Vitamin E) and squalene. The contents of ${\alpha}-tocopherol$ and squalene extracted from freeze-dried ground Pandanus odorus leaves at pressures ranging from 80 to $200\;kg\;cm^{-2}$ and temperatures between 40 to $80^{\circ}C$ were $134{\sim}300\;ppm$ and $750{\sim}1,200\;ppm$ respectively. The highest yield was obtained at $200\;kg\;cm^{-2}$ and $40^{\circ}C$. Other major components identified were hexadecanoic acid, 9,12,15-octadecatrien-1-ol, campesterol, stigmasterol and ${\beta}-sitosterol$.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Journal of the Korean Applied Science and Technology
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• v.21 no.3
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• pp.204-213
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• 2004

Extraction of Sedum sarmentosum Bunge by super critical carbon dioxide was operated under $40-50^{\circ}C$and 200-250 atm, thus, yield of extraction was very low as 4 wt%. Rats were administrated with the extract orally once a day for succesive 6 days, followed by treatment with carbon tetrachloride ($CCl_4$) on the sixth day. The activities of aminotransferase, alkaline phosphatase, ${\gamma}$-glutamyl transpeptidase, lactate dehydrogenase and contents of triglyceride, total cholesterol in the extract-pretreated rats were decreased compared to the $CCl_4$controled rats, whereas content of HDL-cholesterol was increased. Especially content of hepatic malondialdehyde (MDA) and atherogenic index (AI) were decreased and HTR was increased in the extract-pretreated rats, and reduced peroxidative liver damage in the $CCl_4$-induced hepatotoxicity rats. In addition, activities of hepatic superoxide dismutase, catalase, glutathione peroxidase in the extract-pretreated rats were significantly decreased compared to the $CCl_4$ controled rats, but the content of glutathione was significantly increased. These results suggest that extract of Sedum sarmentosum Bunge has hepatoprotective effect in the $CCl_4$-intoxicated rats.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.61-66
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• 1997

Recently, incidences of pulmonary-related diseases are increasing and natural ecosystem is destroyed year by year owing to air pollutions by industrial noxious gases such as sulfur dioxide and carbon dioxide, etc. Sulfur dioxide produced by oxidation of sulfur compounds is water soluble and causes several kinds of pulmonary diseases, damaging on plants and animals. This study was undertaken to investigate effects of acute exposure of rats to sulfur dioxide using biochemical parameters. The sAST (aspartate transaminase) activity was not significantly affected but sALT (alanine transaminase), sLDH (lactate dehydrogenase) and sALP (alkaline phosphatase) activities were significantly increased by acute sulfur dioxide gas exposure. Also sulfur dioxide gas treatment significantly diminished serum cholinesterase activity. The total lipid, triglyceride, total-, HDL- and LDL-cholesterol contents were significantly increased by sulfur dioxide gas exposures. But the body and liver weight were generally diminished in comparison with control group. Our results' showed increased enzyme activities and lipid contents, but body and liver weight were all diminished by sulfur dioxide gas treatment.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.18-24
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• 2016

Mineral carbonation is a technology for permanently storing carbon dioxide by reacting with metal oxides containing calcium and magnesium. In this study, we used sea water and alkaline industrial by-product such as paper sludge ash (PSA) for the storage of carbon dioxide through direct carbonation. We found the optimum conditions of both sea water content (mixing ratio of sea water and PSA) and reaction time required in the direct carbonation through various experiments using sea water and PSA. In addition, we compared the amounts of carbon dioxide storage with the cases when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA. The amount of carbon dioxide storage was calculated by using both solid weight increase through the carbonation reaction and the contents of carbonate salts from thermal gravimetric analysis. PSA particle used in this study contained 67.2% of calcium. The optimum sea water content and reaction time in the carbonation reaction using sea water and PSA were 5 mL/g and 2 hours, respectively, under the conditions of 0.05 L/min flow rate of carbon dioxide injected at $25^{\circ}C$ and 1 atm. The amounts of carbon dioxide stored when sea water and ultra-pure water were separately used as solvents in the direct carbonation with PSA were 113 and $101kg\;CO_2/(ton\;PSA)$, respectively. The solid obtained through the carbonation reaction using sea water and PSA was composed of mainly calcium carbonate in the form of calcite and a small amount of magnesium carbonate. The solid obtained by using ultra-pure water, also, was found to be carbonate salt in the form of calcite.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.20-24
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• 2010

This study was performed to investigate antioxidant activities of Mistletoe (MS) extracts by measuring electron donating ability (EDA), super oxide dismutase (SOD)-like activity and total polyphenol content (TPC). The extracts were obtained using supercritical carbon dioxide, hot-water and ethanol extraction. EDAs was the higher in ethanol extract (70.53%) than water (36.73%) or supercritical carbon dioxide extract (15.73% at 400 bar, $30^{\circ}C$) at concentration of 10 mg/mL. However, SOD-like activities and TPCs were the highest in the supercritical carbon dioxide extract. At concentration of 1 mg/mL, supercritical carbon dioxide extract (22.54% at 200 bar, $40^{\circ}C$) was higher SOD activity than water (7.85%) and ethanol extract (6.12%). Regarding TPCs of MS extracts, the content was the highest in supercritical carbon dioxide extract (17.57 wt% catechin equivalent at 200 bar, $50^{\circ}C$) followed by ethanol and water extract. These results suggest that it can be useful to develop functional foods using antioxidative active compounds of MS with high polyphenol contents.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.21-26
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• 2005

Experimental researches on the preparation of porous polymeric monoliths in supercritical carbon dioxide have been performed and the effects of monomer and polymerization parameters on the physical properties of the monolith prepared were examined. Polymerizations were carried out in the high pressure stainless steel reactor with sapphire window to show the phase change during the polymerization reaction, and continuous and dry porous monolithic polymer could be obtained. The specific surface area of monolithic polymer increased with monomer contents in reaction mixture and reaction pressure. The Rockwell hardness could be enhanced by the addition of co-monomer MMA in reaction mixtures.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.4
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• pp.368-377
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• 2015

Bunker C fuel oil is a high-viscosity oil obtained from petroleum distillation as a residue. The sulfur content of bunker C fuel oil is limited to 4.0% or even lower to protect the environment. Because bunker C fuel oil is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, carbon dioxide is emitted as a result of combustion. The objective of this study is to investigate $CO_2$ emission characteristics of bunker C fuel oil by sulfur contents. Calorific values and carbon contents of the fuels were measured using the oxygen bomb calorimeter method and the CHN elemental analysis method, respectively. Sulfur and hydrogen contents, which were used to calculate the net calorific value, were also measured and then net calorific values and $CO_2$ emission factors were determined. The results showed that hydrogen content increases and carbon content decreases by reducing sulfur contents for bunker C fuel oil with sulfur contents less than 1.0%. For sulfur contents between 1.0% and 4.0%, carbon content increases as sulfur content decreases but there is no evident variation in hydrogen content. Net calorific value increases by reducing sulfur contents. $CO_2$ emission factor, which is calculated by dividing carbon content by net calorific value, decreases as sulfur content decreases for bunker C fuel oil with sulfur contents less than 1.0% but it showed relatively constant values for sulfur contents between 1.0% and 4.0%.

• Journal of Mushroom
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• v.10 no.1
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• pp.3-8
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• 2012

In this study, to produce Flammulina velutipes mushroom liquid spawn efficiently and effectively the effects of explosive aeration (supplying air with tiny bubbles) of the liquid culture medium on carbon dioxide concentration and residual sugar content in the medium on carbon dioxide concentration and residual sugar contentin the medium were measured. Carbon dioxide concentrations were measured at the outlet of the incubator. On the third day the explosive aeration greatly increased mycelial growth of the liquid spawn, and carbon dioxide concentration also greatly increased but decreased after 5 days. Free sugar contents in the liquid culture consistantly decreased up to 7 days and thereafter was not detected. The weight of the mycelia were maintained similar levels after 3 days. Total nitrogen content in the liquid medium constantly decreased during the 11days of explosive aeration. The content of free sugars in 7 days of culture was the lowest level, thus the inoculum incubated for 6~7 days was thought to be the most effective. Carbon dioxide concentration measurement at the outlet of the container during the liquid spawn incubation required low cost but was efficient to estimate the degree of mycelial growth to be used as a simple indicator.