• Fire Science and Engineering
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• v.23 no.6
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• pp.1-9
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• 2009

In this study, the burning behaviours of five different kinds of carpet samples covered with nylon, PP (polypropylene), PTT (poly(trimethylene terephthalate)), wool fabric and NW (nylon and wool) were evaluated by using the cone calorimeter having a radiant flux of 50kW/$m^2$. And the combustion gas toxicity was evaluated according to KS F 2271 test method. As a result of the cone calorimeter test (KS F ISO 5660-1), nylon carpet samples were ignited most easily. In ignition ability or initial flammability, NW carpet samples showed the highest value. In heat release rate (HRR), fire intensity, PP carpet samples were larger than any other samples. Nylon carpet samples were the highest smoke production rate, while N/W carpet samples the lowest. The following were in mass loss rates: NW > wool > nylon > PP > PTT. CO (carbon monoxide) was one of the most toxic gases released from the combustion. PTT carpet samples gave rise to the highest CO concentration, while NW carpet samples the lowest. In addition, PP carpet samples caused the highest $CO_2$ (carbon dioxide) concentration, while NW carpet samples the lowest. Toxicity of the gas produced from carpet samples was determined by the mouse stop motion, and it resulted in the fact that the combustion gas of PTT carpet samples was more toxic than that of any other samples.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.6
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• pp.332-338
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• 2017

The purpose of this study was to determine optimum value of aeration, acetate dosage, and $CO_2$ input for the cultivation of Scenedesmus acuminatus. Highest specific growth rate and maximum biomass productivity was obtained by the aeration of 0.72 vvm and lower specific growth rates and maximum biomass productivity were obtained for other aeration tests. When putting 0.3 M of ammonium acetate in JM medium, the highest specific growth rate and maximum biomass productivity were obtained. $CO_2$ input tests were performed during semi-continuous culturing tests. The highest specific growth rate ($0.460d^{-1}$) and maximum biomass productivity ($0.936gL^{-1}d^{-1}$) were obtained after replacing 50% of solution with 0.3 M of acetate solution for $CO_2$ input tests. However, more dilutions after the first dilution resulted in lower specific growth rate and maximum biomass productivity. In aeration tests, the highest specific growth rate ($0.381d^{-1}$) and maximum biomass productivity ($0.253gL^{-1}d^{-1}$) were obtained when cultivating it with JM medium, but the specific growth rate and maximum biomass producitivty were significantly decreased when 50% of solution was replaced by acetate containing solution.

• ALGAE
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• v.31 no.4
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• pp.351-362
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• 2016

We investigated a possible reduction in $CO_2$ uptake rate by phototrophic red tide dinoflagellates arising from mixotrophy. We measured the daily ingestion rates of Prorocentrum minimum by Prorocentrum micans over 5 days in 10 L experimental bottles, and the uptake rates of total dissolved inorganic carbon ($C_T$) by a mixture of P. micans and P. minimum(mixotrophic growth), and for the predator P. micans (phototrophic growth; control) and prey P. minimum (phototrophic growth; control) alone. To account for the effect of pH on the phototrophic growth rates of P. micans and P. minimum, measurements of $C_T$ and pH in the predator and prey control bottles were continued until the pH reached the same level (pH 9.5) as that in the experimental bottles on the final day of incubation. The measured total $C_T$ uptake rate by the mixture of P. micans and P. minimum changed from 123 to $161{\mu}mol\;C_T\;kg^{-1}\;d^{-1}$ over the course of the experiment, and was lower than the $C_T$ uptake rates shown by P. micans and P. minimum in the predator and prey control bottles, respectively, which changed from 132 to $17{\mu}mol\;C_T\;kg^{-1}\;d^{-1}$ over the course of the experiment. The reduction in total $C_T$ uptake rate arising from the mixotrophy of P. micans was 7-31% of the daily $C_T$ uptake rate seen during photosynthesis. The results suggest that red tide dinoflagellates take up less $C_T$ during mixotrophy.

• Tuberculosis and Respiratory Diseases
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• v.55 no.6
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• pp.560-569
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• 2003

Background : A large number of pollutants such as sulfur dioxide, nitric oxide, carbon monoxide, particulate matter, and ozone influence on the body. These pollutants put a burden on the lung and the sequelae resulting from the oxidative stress are thought to contribute to the development of fibrotic lung disease, emphysema, chronic bronchitis and lung cancer. Also, carbon monoxide generated from the incomplete combustion of carbon-containing compounds is an important component of air pollution caused by traffic exhaust fumes and has the toxic effect of tissue hypoxia and produce various systemic and neurologic complications. The objective of this study is to compare the difference of pulmonary function and serum carboxyhemoglobin(CO-Hb) level between the traffic policemen and clerk policemen. Method : Three hundred and twenty-nine of traffic policemen, and one hundred and thirty clerk policemen were included between 2001 May and 2002 August. The policemen who took part in this study were asked to fill out a questionnaire which included questions on age, smoking, drinking, years of working, work-related symptoms and past medical history. The serum CO-Hb level was measured by using carboxyoximeter. Pulmonary function test was done by using automated spirometer. Additional tests, such as elecrocardiogram, urinalysis, chest radiography, blood chemistry, and CBC, were also done. Results : $FEV_1(%)$ was $97.1{\pm}0.85%$, and $105.7{\pm}1.21%$(p<0.05). FVC(%) was $94.6{\pm}0.67%$, and $102.1{\pm}1.09%$, respectively(p<0.05). Serum CO-Hb level was $2.4{\pm}0.06%$, and $1.8{\pm}0.08%$(p<0.05). After correction of confounding factors (age, smoking), significant variables were FVC(%), $FEV_1(%)$ and serum CO-Hb level(%)(p<0.05). Conclusion : Long exposure to air pollution may influence the pulmonary function and serum CO-Hb level. But, further prospective cohort study will be needed to elucidate detailed influences of specific pollutants on pulmonary function and serum carboxyhemoglobin level.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.6
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• pp.325-331
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• 2017

Adsorption experiments of carbon dioxide were performed on ZSM5 and Molecular Sieve 13X (MS13X) impregnated with Monoethanol Amine (MEA). Adsorption efficiency of $CO_2$ was investigated in a U type packed column with GC/TCD. The adsorption capacities of adsorbents are estimated in the temperature range of $30-80^{\circ}C$. The modified adsorbents was characterized by BET surface area, $N_2$ adsorption/desorption isotherms, X-ray diffraction and FT-IR. Surface analysis results showed that the impregnation method did not affect the crystallinity of any adsorbents. BET surface area of the MS13X impregnated amine decreased to $19.945m^2/g$ from $718.335m^2/g$. These reults showed that amine molecules were filled with the pore volume in MS13X, as a results restricting access of nitrogen into the pores. The MEA modified MS13X showed improvement in $CO_2$ adsorption capacity over the ZSM5 impregnated with MEA. The MS13X-MEA showed the highest adsorption capacity due to physical adsorption and chemical adsorption by amino-group content. This results also showed that adsorption capacity of MS13X-MEA increases with the temperature range of $60-80^{\circ}C$ compared with pristine MS13X.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.732-739
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• 2013

'Akihime' plums picked at mature stage (50-70% red coloration of the fruit skin) were stored at $1^{\circ}C$ under air or controlled atmosphere (CA) storage regime as following 3% $O_2$ + 1, 3, 5, and 7% $CO_2$ for 50 days for the purpose of assessing the effect of CA storage on the maintenance of fruit quality and the reduction of chilling injury. Fruits stored under CA storage regime showed reduced respiration as well as ethylene production rates compared to the fruits stored in air. Quality attributes including weight loss, Hunter 'a' values, soluble solids content, titratable acidity, and firmness showed smallest changes in fruits stored under CA conditions except for 3% $O_2$ + 7% $CO_2$. High incidence of physiological disorders including chilling injury, flesh browning, and decay were found in fruits stored under both air and CA of 3% $O_2$ + 7% $CO_2$. In our study, the CA storage regime of 3% $O_2$ + 5% $CO_2$ was found the most effective for maintaining overall fruit qualities of 'Akihime' plums produced in Korea, also delayed the development of chilling injury including lack of juiciness and flesh browning. From the results, storage at 3% $O_2$ + 5% $CO_2$ was selected as an optimal condition of 'Akihime' plum for extending storage life up to 50 days at $1^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3348-3354
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• 2011

Oleanolic acid (OA) as template molecule, polyamide-6 (PA6) as basement membrane and poly(styrene-comaleic acid) (PSMA) were used to prepare PA6/PSMA-OA molecularly imprinted composite membranes by phase inversion method in supercritical $CO_2$ ($ScCO_2$). The template molecule (OA), [poly(styrene-co-maleic anhydride) (PSMAH), PSMA, molecularly imprinted membranes (MIMs) imprinting OA and MIMs after elution were all characterized by Fourier transform infrared spectroscopy (FTIR). The conditions that were the mass ratio between PSMA and OA from 3:1 to 8:1, temperature of $ScCO_2$ from $35^{\circ}C$ to $50^{\circ}C$ and pressure of $ScCO_2$ 12 MPa to 17 MPa were studied. It was obtained the largest adsorption rate and purity of OA after adsorption of the resultant MIMs, 50.41% and 96.15% respectively. After using PA6 film and non-woven fabrics as basement membrane respectively, it was found that smaller aperture of PA6 was used as basement membrane, a higher adsorption rate and a higher purity of OA after adsorption of the MIMs were obtained, and so were the stability and reproducibility of the resultant MIMs. After template molecules being removed, the MIMs had effective selectivity hydrogen bonding to separately bind in the binary components to the template molecules-oleanolic acid.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.353-361
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• 2013

An in situ mesocosm experiment was designed to investigate how exposure to ocean acidification by increased carbon dioxide affected the growth of juvenile oliver flounder (Paralichthys olivaceus). A total of 447 individuals were reared in the mesocosm experimental devices deployed at sandy-muddy bottom in the southern coast of East Sea for 43 days and divided into two groups: treatment group (223 individuals, $6.32{\pm}0.75$ cm, high-$CO_2$ environment) and control group (224 individuals, $6.34{\pm}0.84$ cm, natural $CO_2$ environment). The average values of pH and $CO_2$ concentration in the treatment device were $7.63{\pm}0.13$ and $1660{\pm}540$ ${\mu}atm$, respectively, while those in the control device were $8.07{\pm}0.05$ and $514{\pm}65$ ${\mu}atm$, respectively. There was no significant difference in mortality rate between treatment and control group, and the mortalities in two groups gradually decreased during the study period. But, the increase of size and weight of juvenile oliver flounder was higher in control group than treatment group, i.e., weight gain or growth rate was higher in control group. These results suggested that high $CO_2$ environments could have a significant negative influence on the early growth of juvenile oliver flounder.

• Clean Technology
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• v.24 no.1
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• pp.41-49
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• 2018

Y zeolites with different extra-framework cations, such as $Na^+$, $N^+$, $Ca^{2+}$, and $Cu^{2+}$, with different charge and ionic radius have been investigated to greatly enhance a working capacity (W) of $CO_2$ adsorption at $25^{\circ}C$ and a $CO_2/CO$ selectivity factor (S). A sample of NaY with a very small amount of 0.012% $Ca^{2+}$ was fully reversible for seven times repeated $CO_2$ adsorption/desorption cycles, thereby forming no surface carbonates unlikely earlier reports. Although at pressures above 4 bar, 2.00% CaY, 1.60% CuY and 1.87% LiY all showed a $CO_2$ adsorption very similar to that measured for NaY, they gave a significant decrease in the adsorption at lower pressures, depending on the metal ion. At 0.5 ~ 2.5 bar, the extent of $CO_2$ adsorption was in the order NaY > 1.60% CuY > 2.00% CaY > 1.87% LiY. All the $Na^+-based$ metals-exchanged zeolites have a FAU (faujasite) framework and a Si/Al value near 2.6; thus, there is no discernible difference in the framework topology, framework chemical compositions, effective aperture size, and channel structure between the zeolite samples. Therefore, the distinctive behavior in the adsorption of $CO_2$ with a character as a weak Lewis acid is associated with the site basicity of the zeolites, and the interaction potentials of the cations. Different trend was shown for a CO adsorption due to weaker quadrupole interactions. Adsorption of $CO_2$ and CO on samples of CaY with 0.012 to 5.23% Ca disclosed a significant dependence on the Ca loading. The $CO_2$ adsorption increased when the cation exists up to ca. 0.05%, while it decreased at higher Ca amounts. However, values for both W and S could greatly increase as the bare zeolite is enriched by $Ca^{2+}$ ions. The 5.23% CaY had $W=2.37mmol\;g^{-1}$ and S = 4.37, and the former value was comparable to a benchmark reported in the literature.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.181-191
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• 2024

In the realm of cement manufacturing, concerted efforts are underway to mitigate the emission of greenhouse gases. A significant portion, approximately 60%, of these emissions during the cement clinker sintering process is attributed to the decarbonation of limestone, which serves as a fundamental ingredient in cement production. Prompted by these environmental concerns, there is an active pursuit of alternative technologies and admixtures for cement that can substitute for limestone. Concurrently, initiatives are being explored to harness technology within the cement industry for the capture of carbon dioxide from industrial emissions, facilitating its conversion into carbonate minerals via chemical processes. Parallel to these technological advances, economic growth has precipitated a surge in construction activities, culminating in a steady escalation of construction waste, notably waste concrete. This study is anchored in the innovative production of calcium silicate cement clinkers, utilizing finely powdered waste concrete, followed by a thorough analysis of their mineral phases. Through X-ray diffraction(XRD) analysis, it was observed that increasing the substitution level of waste concrete powder and the molar ratio of SiO₂ to (CaO+SiO₂) leads to a decrease in Belite and γ-Belite, whereas minerals associated with carbonation, such as wollastonite and rankinite, exhibited an upsurge. Furthermore, the formation of gehlenite in cement clinkers, especially at higher substitution levels of waste concrete powder and the aforementioned molar ratio, is attributed to a synthetic reaction with Al₂O₃ present in the waste concrete powder. Analysis of free-CaO content revealed a decrement with increasing substitution rate of waste concrete powder and the molar ratio of SiO₂/(CaO+SiO₂). The outcomes of this study substantiate the viability of fabricating calcium silicate cement clinkers employing waste concrete powder.