• Journal of the Architectural Institute of Korea Structure & Construction
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• 제34권3호
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• pp.37-42
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• 2018

The use of fly ash in construction materials is increasing worldwide due the various advantages of using it, such as to produce durable concrete, or to use less cement and thus lower carbon dioxide emissions. The quality of fly ash is often determined by loss on ignition value (LOI), where an upper limit of LOI is set in each country for quality control purpose. However, due to many reasons, production of high LOI fly ash is increasing that cannot be utilized in concrete, ending up in landfill. In this study, the effect of fly ash use in cementitious materials on nitrogen oxides adsorption is examined. In particular, the effect of using high LOI, and thus high carbon content fly ash on nitrogen oxides adsorption is investigated. The results suggest that the higher carbon content fly ash is related to higher nitrogen dioxide adsorption, although normal fly ash was also more effective in nitrogen dioxide adsorption than ordinary portland cement. Also, higher replacement rate of up to 40% of fly ash is beneficial for nitrogen dioxide adsorption. These results demonstrate that high carbon fly ash can be used as construction materials in an environmentally friendly way where strength requirement is low and where nitrogen oxides emissions are high.

• Korean Journal of Metals and Materials
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• 제48권3호
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• pp.187-193
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• 2010

The solute carbon content in ferrite is one of the important factors to obtain good formability in low carbon steels. Although most of the carbons are consumed by the formation of grain boundary cementite during coiling after hot-rolling, the carbon content after coiling is normally observed much more than that of equilibrium. In this study, a classical nucleation and growth model is used to simulate the precipitation kinetics of the grain boundary cementite from coiling temperature (CT) to room temperature (RT). The predicted precipitation behaviors depending on the initial carbon content and the cooling rate are compared with the reported. As a result, the lateral growth of thickening of cementite is a major factor for the sluggish reaction of grain boundary cementite. The reduction of solute carbon content after coiling is divided into three regions: a) increase due to no cementite precipitation, b) decrease due to the fast length-wise growth of cementite, c) increase due to the slow thickness-wise growth of cementite.

• Korean Chemical Engineering Research
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• 제60권4호
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• pp.478-485
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• 2022

The certification performance issued through an external business is sold to companies subject to the emission trading system allocation, and the company subject to the allocation can secure the quota by converting the purchased external business certification performance into offset credits. In this methodology, when fossil fuels that used existing oil boilers (by oil type) were replaced with boilers using propane gas with a relatively low carbon content, the amount of carbon dioxide emission reduction by oil type was recognized. As an initial analysis to make up for the insufficient quota of large corporations, the amount of carbon reduction emissions and emission rights trading was calculated.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제10권4호
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• pp.199-204
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• 1977

The patterns of fatty acid composition of lipid extracted from eight species of edible marine benthic algae; i. e. two species of green, five of brown and one of red algae, were investigated quantitatively by using gas liquid chromatography. The total lipid contents in average of the algae were $1.51\%$ in the green algae, $2.81\%$ in brown algae and $1.02\%$ in red algae respectively. Upon analyzing fatty acid composition, green algae contained the highest proportion of $C_{16:0}$ acid and comparatively higher content of $C_{18:1},\;C_{18:2}\;and\;C_{18:3}$ acids than the other algae. In brown angae, $C_{16:0}$ acid content was highest, but not more than that of green algae, and $C_{14:0},\;C_{18:1}$ acids were higher than other $C_{16:1},\;C_{18:2}\;and\;C_{18:3}$ acids while the content of $C_{18:0}$ acid was very low. Red algae showed low content of $C_{14:0},\;C_{18:1},\;C_{18:2}\;and\;C_{18:3}$ acids, but the content of $C_{16:0}$ acid was high as a major component. In regard to the composing patterns of carbon number of fatty acid of algae; i. e. $C_{14},\;C_{15},\;C_{16},\;C_{18}\;and\;C_{22}$ and $C_{22}$ acids, the green algae contained $C_{16}$ and $C_{18}$ acids, the brown algae $C_{16},\;C_{18},\;and\;C_{22}$ and $C_{22}$ acids, and the red algae $C_{15},\;C_{16}$, and $C_{18}$ acids as the major component.

• Food Science and Preservation
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• 제15권6호
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• pp.897-902
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• 2008

The effect on serum lipid of green aster juice blended with ginseng and carrot extracts was investigated using rats injected with $CCl_4$. The rats were classified with four groups: (i) normal control (NC), (ii) rats fed with the blended juice (BA), (iii) rats treated with $CCl_4$ after having been on a normal diet for 4 weeks ($NC-CCl_4$), and (iv) rats treated with $CCl_4$ after having been fed the blended juice for 4 weeks ($BA-CCl_4$). All groups had similar feed intake. The weight gains and feed efficiency ratio were lower in the $NC-CCl_4$ group. The liver weight per body weight was much higher in the $NC-CCl_4$ group than the NC group, but did not differ between the $BA-CCl_4$ and BA groups. Triglycerides increased only for the $NC-CCl_4$ group (88.72 mg/dL); the other groups had similar levels (56.48-65.33 mg/dL). The BA group had the lowest total cholesterol level (74.08 mg/dL) the other groups had similar levels (96.78-108.83 mg/dL). HDL-cholesterol was lower in the $NC-CCl_4$ group (40.56 mg/dL) compared with the NC group (48.95 mg/dL), but there was no difference between the BA and $BA-CCl_4$ groups. The LDL-cholesterol level was higher in the $NC-CCl_4$ group (55.20 mg/dL the highest level) than the NC group (43.33 mg/dL), and higher in the $BA-CCl_4$ group (50.10 mg/dL) than the BA group (18.09 mg/dL). The lipid peroxide content was much higher in the $NC-CCl_4$ group (22.61 nmol/g) than the NC group (12.52 nmol/g), but the $BA-CCl_4$ (17.41 nmol/g) and BA (13.99 nmol/g) groups were similar. The glutathione content was much lower in the $NC-CCl_4$ group ($2.25\;{\mu}mol/g$) than the NC and BA groups, and decreased to $2.63\;{\mu}mol/g$ for the $BA-CCl_4$ group. The glutathione content of the $BA-CCl_4$ recovered to the level of that in the NC group.

• Resources Recycling
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• 제15권1호
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• pp.66-73
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• 2006

The effects of operation conditions, such as bed temperature, temperature rising rate, particle size, moisture content and so on, on thermo-chemical conversion of waste wood have been determined in a micro fixed bed gasifier. The samples were waste wood-chips such as pine, oak, acacia and ginkgo. The thinning timbers used as reactants in the experiments had $35wt\%$ moisture content, $0.5wt\%$ ash content and 4,550 kcal/kg heating value on a dry basis. A typical product distribution was a $40wt\%$ liquid, $20wt\%$ solid, and $40wt\%$ dry syngas. The syngas concentration was affected by operation conditions and average syngas concentration was $H_2:40vol\%,\;CO:30vol\%,\;CH_4:10vol\%$.

• Korean Journal of Plant Tissue Culture
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• 제22권2호
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• pp.111-114
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• 1995

To produce ${\gamma}$-linolenic acid (GLA) by cell cultures of Lithospermum erythrorhizon, we optimized medium compositions including carbon sources, nitrogen sources and growth regulators. MS basal medium supplemented with 1.0 mg/L 2, 4-D was effective for callus induction from mesophyll tissue. Addition of sucrose at 88mM concentration induced active proliferation of suspension cells and increased GLA content. Increased supplement of potassium nitrate as nitrogen source resulted in proliferous cell growth and increased total fatty acid content Abscisic acid increased cell growth and fatty acid content in callus culture, whereas as it had an inhibitory effect in suspension cell culture.

• Polymer(Korea)
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• 제35권1호
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• pp.17-22
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• 2011

Polypropylene/multi-walled carbon nanotube(PP/MWCNT) composites along with various MWCNT contents up to 20 wt% were prepared by a twin screw extruder. Nanocomposites having 20 wt% MWCNT as a master batch(M/B) were diluted with PP by way of melt compounding. The electrical/thermal conductivity, morphology, thermal/viscoelastic/mechanical properties were investigated with the variation of MWCNT contents. Also, we compared some properties between 1-step PP/MWCNT and the diluted PP/MWCNT composites. The percolation threshold of electrical and thermal conductivity was measured at about 3 wt% MWCNT. And conductivity of diluted PP/MWCNT composites were superior to those of PP/MWCNT composites. The non-isothermal crystallization temperature and thermal decomposition temperature appeared at higher temperatures with increasing MWCNT contents. Morphology showed that length of MWCNT in diluted PP/MWCNT composites was shortened by twice melt blending, which contributed to improve the tensile strength of PP/MWCNT composites.

• Journal of Ginseng Research
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• 제13권1호
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• pp.60-65
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• 1989

The Quality characteristics of pH, ginsenosides, fatty acid, phenolic compounds were studied for their changes during growth of Candia parapsilosis. The yeast growth not only scarcely affected the total amount of saponins and ginsenosidvs of recd ginseng tail root extract, but also was not affected by the saponin C. pnrapsilosis did not utilize the ginsenosides as a carbon source. Glucose, fructose and free sugars were utilized in the initial phase of growth, whereas sucrose and maltose were used as the growth continued and completely redured after 43 hours of incubation. Unsaturated fatty acids were significantly reduced with cell growth, showing a relationship between unsaturated fatty acid content and the yeast growth, whereas the amount of saturate[1 tatty acids in red ginseng extract was not affected by the yeast growth. Generally, there were no changes in major organic acids and phenolic compounds (vanillie acid , m-coumaric acid) except the 50% reduction in maltol and ferulic acid in the ginseng extract. The amounts of amlno acids were gradually decreased, but that of arginine was remarkably reduced.

• Korean Journal of Microbiology
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• 제39권3호
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• pp.155-160
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• 2003

The wild type and two morphological variants of Streptomyces viridochromogenes were studied for their lipidand fatty acid compositions at different incubation temperatures. It showed that a decrease in triacylglycerol content was closely linked to the aerial mycelium formation. Phospholipids showed no characteristic changes, except that the contents of phosphatidylethanolamine were clearly high for aerial mycelium deficient strain BR2 grown at $20^{\circ}C$. The strain BR2 also presented unidentified aminolipids with various $R_{f}$ values. Among the aminolipids, ornithinolipid increased gradually during the cultivation for all strains. The changes in fatty acid compositions showed a temperature dependency that the proportion of unsaturated acids decreased as the growth temperature increased. The proportion of straight chain saturated fatty acids decreased as the aerial mycelium developed, and it was most evident for the mutant strain M13 with more extensive aerial mycelium. The mutant strain BR2 presented significantly higher level of iso branched odd numbered saturated fatty acids.