• The Journal of Engineering Geology
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• v.19 no.3
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• pp.365-371
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• 2009

This paper address the characteristics of loading pollutants caused by the unit agricultural area to establish an efficient management method in NPS (non-point source). The relationship between rainfall and runoff shows good coefficient with 0.92, when the event which shows relatively long antecedent dry days is excepted. The impact of runoff volume on the runoff coefficient can be described by the rainfall intensity strongly. The pollutant EMCs (event mean concentrations) in runoff increased by the increase of antecedent dry days due to dry soil conditions. As the similar pattern of pollutant's loads such as TSS, BOD, COD, TN and TP, it is cleared that other pollutants can be removed when TSS is removed. Therefore the system using only runoff coefficients is not sufficient for the prediction of pollutant loads. It is necessary to consider soil conditions such as rainfall, antecedent dry day, antecedent rainfall etc. for the prediction system.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.93-100
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• 2005

Comparative thickening and dewatering characteristics of municipal wastewater sludge were investigated in terms of separated and combined treatment of primary and secondary BNR sludge. Also, various conditioning methods such as cation polymer addition, steam and ultrasonication treatment were examined to improve dewaterability of sludge. The dewaterability was measured by using specific resistant test, wedge zone simulator and centrifuge. The result of the sludge thickening test revealed that separated thickening was better in terms of solids recovery and supernatant quality. Particularly, the thickening of primary sludge with high solids (about 3.5% TS) showed very poor solid separation. The addition of cation polymer showed better conditioning characteristic for dewatering and the optimal polymer dosage was 0.26% for primary sludge, 0.43% for secondary sludge and 0.38% for combined sludge. Contrary to the result of the thickening, the dewatering test revealed that dewatering of the combined sludge is better than that of separated sludge, representing better solids separation and filtrate quality. The polymer addition was essential to improve dewaterability in filter (belt) press type dewatering but it was inefficient for the dewatering of secondary sludge only. The centrifuge type dewatering showed better performance and the dewaterability was slightly improved when the polymer was added. Based on the results of this research a sustainable sludge treatment process, particularly in terms of the recycle water quality and solids recovery, was proposed.

• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.47-56
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• 2001

In the present study, mainly to determine the embarkation time of equipment in dredged clay fills, an analytical approach is performed to predict a variation of the undrained shear strength in the outermost layer. In this approach, Gibson's non-dimensional linear constant defining the relationship between the void ratio and the effective stress is employed. Also in this approach, void ratios and settlements associated with the volume change due to the self-consolidation and the desiccation shrinkage are evaluated at various elapsed times based on the finite difference solution technique proposed by the authors(1999) and the developed computer program named as DSCON. Predicted results(water content ratio, unit weight and undrained shear strength) are compared with those of laboratory model tests conducted with soil samples obtained from the Koheung site. Based on the predicted undrained shear strengths, possible embarkation time of a equipment is also evaluated. In addition, further analyses are made to indirectly verify the efficiency of the analytical approach proposed in the present study using the PSDDF computer program which can consider the drainage efficiency.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.65-74
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• 2018

The degree of compaction of embankments is generally measured using the sand replacement method or a soil density gauge. However, these methods include coarse particles, which are relatively large. The degree of compaction is overestimated if the in-situ soil density is simply compared with the density obtained from a Proctor compaction test (KS F 2312, 2001), because the density of coarse particles is higher than that of soil. However, there is no recommended correction for the coarse particle ratio in Korea, thus intentionally increasing the degree of compaction for structures to which large loads are applied or for which compaction is critical. Here, a correction considering the Korean Proctor compaction test and the difference between the maximum allowable particle sizes was recommended after corrections for coarse particle ratios in other countries were collected and analyzed. The degree of compaction was re-estimated by applying the recommended correction to the results of both Proctor compaction and sand replacement tests. The degree of compaction without the correction of coarse particle ratio was overestimated, because the re-estimated degree of compaction decreased as the coarse particle ratio increased. The relatively accurate results obtained from the field application of the correction will offer long-term cost savings due to reduced maintenance fees during operation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.819-825
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• 2002

The present study was conducted to investigate the effect of dietary supplementation of sea tangle extracts on the excretion of neutral steroids and bile acid in diabetic rats. Sprague-Dawley rats were fed on AIN-76 based experimental diets containing methanol extracts (2%, w/w) or water extracts (4%, w/w) of sea tangle for 4 weeks. And then they were induced to be diabetic by receiving streptozotocin (45 mg/kg BW) intramuscularly. The dried fecal weight was increased significantly in water extracts group compared with control group. The fecal content of cholesterol was higher in extracts groups of sea tangle than in control group. But there was no significant difference in fecal excretion of cholesterol between methanol and water extracts groups. The fecal excretion of coprostanol was increased significantly in water extracts group compared with the control group. The fecal excretion of bile acid was increased significantly in sea tangle extracts groups compared to the control group. These data suggest that dietary supplementation of sea tangle extracts might reduce the incidence of atherosclerosis through increasing the excretion of neutral steroids.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.367-370
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• 2003

This study was carried out to investigate the possibility for reuse of solid organic wastes such as saccharified newspapers and boxes by two-phase anaerobic fermentation system. When 15g of newspaper and box wastes were digested for 24 days by batch fermentation, tCOD removal rate were found to be 60.9 and 62.4%, respectively. During this period, the amounts of biogas produced were 6.95 and 6.43L. The removal efficiencies of total solid were 34.8 and 33.4%, and those of volatile solid were 40.0 and 39.2%, respectively. That pH was around 7.5 after 20-days operation means methane fermentation is well advanced. In case of semicontinuous reaction, tCOD removal efficiencies of newspaper and box wastes were 64.7 and 65.0%, respectively for 14-days operation. It has been shown that each of the average biogas amounts produced after 25 days operation (stabilization stage for methane fermentation) was 0.31 and 0.30L/g dry wt./day, respectively, and each methane contents was 57.3 and 56.2%, respectively. After the reaction continued for 25 days, pHs in the anaerobic acidogenic and methanogenic fermenters were shown to be 5.0 and 7.5, respectively.

• Journal of Dairy Science and Biotechnology
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• v.35 no.3
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• pp.208-214
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• 2017

The aims of this study were to manufacture a hydrolyzed goat milk protein (HGMP)/chitosan ologisaccharide (CSO) nano-delivery system (NDS) and to investigate the effects of production variables, such as sodium tripolyphosphate (TPP), HGMP, and CSO concentration levels, on the formation and physicochemical properties of the NDS. An HGMP/CSO NDS was produced using the ionic gelation method at pH 5.5. Transmission electron microscopy and a particle size analyzer were used to determine the morphological and physicochemical properties of NDSs, respectively. The size of the HGMP/CSO NDS decreased from 225 to 138 nm as HGMP and CSO concentration levels decreased. The NDS had a positive surface charge, with a zeta-potential value of +23 mV. The encapsulation efficiency (EE) of docosahexaenoic acid was enhanced as the HGMP concentration level increased. Additionally, increasing the concentration level of CSO resulted in an increase in the EE of resveratrol. The HGMP/CSO NDS exhibited good physical stability during freeze-drying. Thus, our findings showed that the HGMP/CSO NDS was successfully manufactured and that HGMP and CSO concentration levels were key factors affecting the physicochemical properties of the NDS.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.615-621
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• 2009

In order to optimize the supercritical fluid extraction (SFE) conditions of volatile components from the strawberry, we conducted an evaluation of the sample preparation and SFE operating conditions. The analysis of the volatile components extracted by a variety of sample preparation protocols led to the identification of 30, 26, 30, and 34 volatile components in fresh, freeze-dried, 30% celite and 70% celite treatments, respectively. The 70% celite treatment was the most effective in extracting the volatile components from strawberry via SFE. Analysis of the volatile components extracted by a variety of SFE operating conditions yielded identifications of 34, 35, 34, and 35 volatile components at 3,000 psi (40, $50^{\circ}C$) and 6,000 psi (40, $50^{\circ}C$), respectively. The extraction yield of alcohols and acids, and the total volatile component contents, were highest under conditions of 3,000 psi and $55^{\circ}C$. Volatile components from the strawberry were extracted via SFE, simultaneous steam distillation and extraction (SDE), and solvent extraction (SE). The analysis of the volatile components extracted via different extraction methods resulted in the identification of 56, 34, and 32 volatile components in the SDE, SFE, and SE extracts, respectively. The total volatile component contents identified in the SDE, SFE, and SE extracts were $20.268{\pm}1.144$, $21.627{\pm}1.215$ and $2.476{\pm}0.177\;mg/kg$, respectively. The SFE extract evidenced higher contents of sweet flavors such as 2-methylbutanoic acid, 2-methylpropanoic acid, and hexanoic acid than the SDE and SE extracts. SFE proved to be the most appropriate method for the extraction of fresh volatile components from the strawberry.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.1013-1023
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• 2003

This study was performed to improve water quality of stream by applying hydraulic structures (weir and river bed material) made of porous concrete. The physical and chemical characteristics of porous concrete were measured to estimate application possibility of it in hydraulic structures and it was considered as a proper material for the hydraulic structures. In the results of comparison for the component of matters attached on the hydraulic structures made of porous and ordinary concrete, DW (dry weight) amount attached on porous concrete was 1.6 times higher than that on ordinary concrete under the condition of the same flow rate but influence by flow rate (difference of 10 times) was not shown. Therefore, we could understand that the material of media was more important in DW amount than flow rate. The rate of AFDM (ash free dry mass) to DW also was more at porous concrete than at ordinary concrete. Especially, the high rates of nitrogen and phosphorous in matters attached on porous concrete verify that they were removed by assimilation, adsorption and metabolism of periphyton. The removal percentage of SS, BOD, COD, T-N and T-P by hydraulic structures applying porous concrete compared with ordinary concrete was increased by 34.6%, 36.9%, 33.9%, 18.3% and 21.6%, respectively. Therefore, applying porous concrete to hydraulic structure is expected to contribute to improvement of stream water quality.

• The Korean Journal of Food And Nutrition
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• v.13 no.5
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• pp.490-505
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• 2000

Mugwort (Artemisia sp.) abounds on hedgebank, waysides and grassy places in most part of Europe, Asia and Northern America. This herb has long been associated with witch-craft and magic as a protective charm. Mugwort has been a value as a foodstuff of relieving famine. Proximate composition of mugwort is similar to green vegetables, but it has high level in calcium, potassium and vitamin A content. For medicinal uses, the leaves are harvested twice in spring and autumn before the plant comes into flower and are dried for later uses. Aqueous or organic solvents extracts often have physiologically active constituents. Some extracts of mugwort include cineol, thujone, borneol, camphor, caryophyllene, coumarin, cubebene, pinene, linalool, absinthin etc. The dried leaves have traditionally been used as an antihelmintic, anti-inflammatory, antispasmodic, antitumor, hepatic stimulant, chologogue, emmenagogue, febrifuge, stomachic, tonic etc. Mugwort has been used the dried or green leaves as a flavoring and coloring agents for tea, cake. pastry, bread, noodle, alcoholic liquor, soap and hygienic band.