• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.103-113
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• 1993

Every year, over $3.37{\times}10^7$ ton of municipal solid waste is generated in Korea, of which about 28% is organic food waste from restaurant, dining halls and households etc. Methane conversion of the food waste by anaerobic digestion could be a viable approach for energy recovery as well as safe disposal of the waste. However, as food waste is composed of highmolecular complex polymers such as cellulose, lignin and protein, anaerobic digestion of food waste has not been efficient in terms of volumetric loading rate, solid retention time and extent of anaerobic degradation. In this research, the improved anaerobic degradation of food waste was attemped by applying rumen microorganisms to anaerobic digestion. Acidification efficiency of food waste by rumen microorganisms was compared with that of conventional acidogenesis. And optimum acidification conditions by rumen microorganisms were also determined. For the experiments, anaerobic batch reactors of 600 mL was fed with the processed (dried and milled) food waste obtained from a restaurant. Ultimate volatile fatty acid (VFA) yield produced by rumen microorganisms was about 8.4 meq VFA/g volatile solid (VS) that is 95% of the theoretical value. This yield was not much different from that of conventional acidogenesis, but hydrolysis rate was about twice faster. Cumulative VFA concentration increased from 66 meq/L to 480 meq/L, when the initial TS was increased from 1% to 15%. But VFA yield at 15% TS was half of that at 1% TS. This inhibition on the acidification might be caused by the rapid drop of pH and higher concentration of nonionized VFA. Optimal pH and temperature range for the acidification were about 6.0~7.5 and $35{\sim}45^{\circ}C$, respectively.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.295-302
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• 1994

For the development of biological wastewater treatment process using photosynthetic bacteria (PSB), photosynthetic sludge process consisted of anaerobic digestion and PSB reactor were designed for the treatment of swine wastewater and the optimal operating conditions in flask-scale were examined. Photosynthetic bacteria from soil, pond, rice field, ditch etc. were isolated in synthetic medium containing high amount of organic acids and finally isolated one strain KK14 which showed the most degradating ability of organic acids was selected for the treatment of swine wastewater. It was identified as Rhodopseudomonas palustris. In the anaerobic digestion stage, the maximum organic acid productivity was obtained at pH 5.0, $37^{\circ}C$, HRT 2 day and under anaerobic standing condition. The optimal operating conditions of PSB reactor for the treatment of swine wastewater were pH 7.0, $30^{\circ}C$ under 4,000 lux illumination, and optimal initial COD loading (kg COD/kg D. C. W of PSB) was 2 (20% v/v seeding) in the main purification stage. Maximum removal rate of COD reached 92% under the above optimal conditions for 5 days.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.146-151
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• 1987

The storage stability of sardine oil and the effect of BHA on the oxidation of fatty acids especially, highly unsatureted fatty acids like EPA and DHA were investigated. The sardine oil was extracted from round sardine, with chloroform-methanol(2:1 v/v) solvent with/without addition of BHA, and then stored at $30^{\circ}C$. The deterioration of oil was examined periodically by measuring acid value(AV), peroxide value(POV), carbonyl value(COV), and oxygen absorption. The changes in fatty acid composition during the storage was determined by GLC analysis to elucidate the oxidative stability of individual fatty acid. Formation of free fatty acid increased rapidly according to the storage time elapsed in the BHA free oil while it was obviously inhibited in the BHA added oil. Peroxides and carbonyl compounds were formed very rapidly at the beginning of storage of BHA free oil. But in the oil extracted with BHA, formation of peroxides was somewhat inhibited and formation of carbonyl compounds was very strongly inhibited. Principal fatty acids of sardine oil were $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{20:5}\;and\;C_{22:6}$ acids, and $\omega_33$ polyunsaturated fatty acid $(\omega_3\;PUFA)$ content was very high as much as $23\%$ of the total fatty acid content. The oxidative degradation of fatty acids was enhanced at PUFA especially $C_{20:5}$ ana $C_{22:6}$ acid in BHA free oil. However, the oxidation was fairly retarded in the oil extracted with BHA and the both $C_{20:5}$ and $C_{22:6}$ acids remained at the end of a month storage.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.587-595
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• 2000

The most problems of domestic sewage for BNR(Biological Nutrients Removal) process are deficiency of carbon source and low C/N ratio. Primary sludge fermentation is seemed to be one of the best solutions producing biodegradable organic substrates. Soluble organic materials from sludge fermentation are mainly SCFAs(Short-Chain Fatty Acids) with 2~5 carbon atoms. In this research, it was attempted to apply $A_2/O$ process with the side-stream acid fermenter to improve the nutrients removal efficiency. The result showed that proper SCFAs production is about 3.000mg/L with SRT of 4~5 days. SCFAs yield of approximately 0.10~0.16 mg SCFAs(as COD) per mg of primary sludge(as COD) were achieved. The ratio of acetic. propionic. butyric and valerie acid were 1, 0.7, 0.5 and 0.6. Significant improvements of nutrients removal over 70% in BNR process were observed. thus will reduce the demand for chemical dosing to increase nutrients removal efficiency. When the fermentate was entered $A_2/O$ process, the ratio of phosphate release to substrate uptake amounts to $0.34gPO_4-Pg^{-1}COD$.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.111-118
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• 1988

The growth inhibition of enteropathogenic Escheriohia coli $A_2$and Escherichia coli G$_7$, causing the diarrhea in piglets, by the organic acid producing bacteria was studied in vitro. The metabolites of the organic acid bacteria, such as lactic acid, acetic acid inhibited the growth of E. coli $A_2$and E. coli G$_7$ in BL medium. The more the organic acid producing bacteria have ability to produce the organic acids, the higher these bacteria excelled the inhibitory efficacy against enteropathogenic E. coli. Among the strains examined, Lactobacillus casei Y and Streptococcus faecium C showed relatively strong growth inhibition against enteropathogenic E. coli.. When the organic acid producing bacteria and the enteropathogenic E. coli were incubated simultaneously in BL medium, bacteriostasis of E. coli was observed when the pH of BL culture was lowered to 5.0, and bacteriocidal effect was observed when the pH became Bess than 4.5, E. coli. $A_2$was more resistant to the organic acid bacteria than E. coli G$_7$.

• Journal of Life Science
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• v.9 no.3
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• pp.276-281
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• 1999

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in oxygen radicals and their scavenger enzymes of the mussel (Mytilus coruscus) in South Sea of Korea. Protein contents in muscle of cultured mussel in South Sea were remarkably lower (4-14%, respectively) than those of wild mussel in Pohang of East Sea. Superoxide radical activities in muscle of cultured in South Sea were significantly higher 82∼138% than those of wild mussel in Pohang. Hydroxyl radical formations in muscle of cultured mussels in South Sea were significantly 9∼25% higher than those of wild mussels in Pohang. Superoxide dismutase (SOD) activities in muscle of cultured mussels in South Sea were significantly 16∼28% lower than those of wild mussels in Pohang. It is believed that significantly decrease of protein contents in muscle, remarkable increases of superoxide radical and hydroxyl radical in muscle of cultured mussels of South Sea may be used as a biochemical pollutant markers for diagnosis of marine pollutions. These results suggest that near-coastal water as well as neritic water of the south sea might be affected by pollutant.

• Journal of the Korean Chemical Society
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• v.34 no.4
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• pp.352-359
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• 1990

An effecient gas chromatographic method is described to be used routinely for the rapid profiling and identification of biochemically important organic acids. It involves the solid-phase extraction of organic acids from aqueous samples using Chromosorb P as the solid sorbent and diethyl ether as the eluting solvent, with subsequent triethylamine treatment. The resulting triethylammonium salts of acids were directly converted to volatile tert-butyldimethylsiyl derivatives, which were simultaneously analyzed by two capillary columns of different polarity, DB-5 and DB-1701, under the identical temperature programming condition. The retention index (RI) and area ratio (AR) values of each peak measured on DB-5 and DB-1701 enabled rapid identification of acids by computer RI library search and AR comparison. The application of the present method to the organic acid profiling of various complex samples is demonstrated.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.414-417
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• 2001

This research was compared the amount of phosphate solublized by Pantoea agglomerans which can solublize the insoluble phosphate salt hydroxyapatite with the phosphate produced by being treated with various acids. When P. agglomerans grows in the BY medium containing potassium dihydrogenphosphate of phosphate source without hydroxyapatite, it consumed 361mg/L phosphate, during 72hours cultivation. When 4% hydroxapatite was treated with 0.01N citric acid and oxalic aicd, the amount of solublized phosphate was 702mg/L and 537mg/L more than that by P.agglomerans. The maximum amount of solublized phosphate by P. agglomerans was 465mg/L after 48 hours cultivation.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.177-186
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• 2005

In this Paper. we propose vision-based camera localization technique using 3D information which is created by mapping of DEM and mountain image. Typically, image features for localization have drawbacks, it is variable to camera viewpoint and after time information quantify increases . In this paper, we extract invariance features of geometry which is irrelevant to camera viewpoint and estimate camera extrinsic Parameter through accurate corresponding Points matching by Proposed similarity evaluation function and Graham search method we also propose 3D information creation method by using graphic theory and visual clues, The Proposed method has the three following stages; point features invariance vector extraction, 3D information creation, camera extrinsic Parameter estimation. In the experiments, we compare and analyse the proposed method with existing methods to demonstrate the superiority of the proposed methods.

• Korean Journal of Materials Research
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• v.7 no.10
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• pp.898-907
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• 1997

Fe-22Cr-5AI-X(X=Zr, Y)합금을 1143K, 고온 황화(P$s_{2}$=1.11x$10^{-7}$atm, P$O_{s}$ =3.11x$10^{-20atm}$) 및 황화/산화 (P$s_{2}$=8.31x$10^{-8}$atm, P$O_{s}$ =3.31x$10^{-18atm}$) 환경의 복합가스 분위기에서 1-30시간동안 노출하여 합금표면에 형성된 부식층을 관찰하여 SEM/EDS로 분석하였다. Fe-22Cr-5AI합금은 고온 부식환경에서 부식 생성물의 성장은 포물선법칙을 따르고 주요 성분은 결함이 많고 다공질인 철과 크롬의 황화물[(Fe, Cr)Sx]이므로 고온 내식성이 감소하였다. Zr을 1wt%첨가한 Fe-22Cr-5AI합금의 고온 부식거동은 Y을 1wt%첨가한 합금과 비슷한 거동을 나타내었다. 황화환경에서는 Cr의 선택 황화에 의한 크롬 황화물(CrS)이 생성되고 노출시간의 경과에 따라 (Fe, Cr)Sx나 (Cr, Fe)Sx 등의 황화물의 성장으로 고온 내식성이 감소하였다. 그러나 황화/산화환경에서는 초기에는 알루미늄산화물(A $I_{2}$ $O_{3}$)및 지르코늄산화물(Zr $O_{2}$)등이 생성되어 보호적이었으나 15시간이후 부터 (Fe, Cr)Sx나 (Cr, Fe)Sx 의 황화물의 성장으로 고온 내식성이 감소하였다.