• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.304-309
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• 2012

Size verification of small and large bubbles in a bubble column was investigated by employing the dynamic gas disengagement (DGD) method and dual electrical resistivity probe (DRP) method, simultancously. The holdups of large and small bubbles in the bubble column in a given operating condition were obtained by means of the DGD method by measuring the pressure drop variation in the column with a variation of time after stopping the gas input into the column. The size and frequency of bubbles were measured by the DRP method in the same operating condition, from which the bubble holdup of each range of size was obtained. The verification of size in determining the large or small bubbles was decided by comparing the holdups of large or small bubbles measured by the DGD method with that measured by the DRP method. Filtered compressed air and tap water were used as a gas and a continuous liquid medium. The diameter and height of the bubble column were 0.102 m and 1.5 m, respectively. The demarcation size between the large and the small bubbles in the bubble column was 4.0~5.0 mm; the demarcation size was about 5.0 mm when the gas velocity was in the relatively low range, but about 4.0 mm when the gas velocity was in the relatively high range, within this experimental conditions.

• Clean Technology
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• v.20 no.4
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• pp.349-353
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• 2014

Succinic acid is an important precursor in industries producing biopolymers, pharmaceutical and food additives and green solvents. However, due to the high price of petroleum and the global $CO_2$ emission, the biological production of succinic acid from renewable biomass is a novel process due to the fixation of $CO_2$ into succinate during fermentation. In this study, aqueous two phase systems based on imidazolium ionic liquids/$K_2HPO_4$ were used as an effective separation and concentration process for succinic acid. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of imidazolium ionic liquids to aqueous $K_2HPO_4$ solutions in the presence of succinic acid. It can be found that the ability of imidazolium ionic liquids for phase separation followed the order [HMIm][Br]${\fallingdotseq}$[OMIm][Br]>[BMIm][Br]>[EMIm][Br]. The maximum value of extraction efficiency for succinic acid was about 90% and the amount of coextracted water into top phase is proportional to the chain length of cation in imidazolium ionic liquids. It was concluded that the aqueous two phase systems composed of imidazolium ionic liquids/$K_2HPO_4$ was effective for the selective extraction and concentration of succinic acid.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.736-740
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• 2005

As an alternative of yeast, various concentrations to prepare hypo-allergenic bread (HAB). Addition of sodium bicarbonate increased $CO_2$ emission, but at higher than 2.0% caused bitter taste compared to other mixtures. Addition of sucrose significantly increased $CO_2$ emission. HABs 7 ($NaHCO_3$ 2.0g+sucrose 0.63 g) and 8 ($NaHCO_3$ 2.0g+sucrose 1.0g) showed higher grain and color scores. HAB 5 ($NaHCO_3$ 1.5g+sucrose 1.0g) and 6 ($NaHCO_3$ 1.5g+sucrose 2.0g) gave higher aroma and taste scores. HAB 5 showed significantly higher overall acceptability (p<0.05) score than others, whereas HABs 7 and 8, regardless of high external sensory qualities, showed lower overall acceptabilities than HAB 5 due to bitter taste. Prototypical HAB was obtained using wheat flour (100g) and water (62mL) incubated at $37^{\circ}C$ for 4 hr for treatment of b.p pretense (100mg) before adding sodium bicarbonate (1.5%), sucrose (1.0%), NaCl (1.0%), and citric acid (1.0%).

• Journal of Marine Bioscience and Biotechnology
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• v.8 no.1
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• pp.18-23
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• 2016

It is important to design photobioreactor by cheap material for economical microalgal biomass production. In this study, two types of marine photobioreactors (MPBR), made by either polyvinyl chloride (MPBR-PVC) or high density poly ethylene (MPBR-HDPE), are used and performance of these were compared. Tetraselmis sp. KCTC 12236BP is a green marine alga that isolated from Ganghwa Island, Korea, and the strain was used for marine cultivations using MPBR-PVC and MPBR-HDPE. The cultivations were performed three times in the spring season of 2012 using MPBR-PVC and of 2013 using MPBR-HDPE in the coastal area of Young Heung Island. As the results, MPBR-PVC shows higher biomass productivities than MPBR-HDPE, due to its high light transmittance. In the cultivations using MPBR-PVC, the average sea water temperature was $11.5^{\circ}C$ during the first experiment and $16.5^{\circ}C$ during the second and third experiments. Average light intensities during three times for experiments were 407.5, 268.1 and $273.0{\mu}{\cdot}E{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. The maximum fresh cell weight and average biomass productivity were $1.2g{\cdot}L^{-1}$ and $0.12g{\cdot}L^{-1}{\cdot}day^{-1}$. These results showed that Tetraselmis sp. KCTC12236BP were adapted well with the environmental conditions from ocean, and grow in the MPBR-PVC and MPBR-HDPE.

• Journal of Life Science
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• v.22 no.10
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• pp.1420-1427
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• 2012

We investigated the physiological activity and solvent-partitioned fractions of methanol extracts from the green seaweed Sargassum fulvellum. The methanol extract from S. fulvellum was sequentially fractionated with n-hexane (SFMH), methanol (SFMM), buthanol (SFMB), and water (SFMA). We investigated the antioxidant activities of solvent fractions from S. fulvellum by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity and an SOD activity assay. DPPH radical scavenging capacity of SFMM was 79.5% at 10 mg/ml. SOD activity of SFMM was 79.9% at 10 mg/ml. Nitrite scavenging activities of solvent fractions from S. fulvellum were investigated under different pH conditions and showed the most remarkable effect at pH 1.2. In particular, the activity of SFMB was higher than the other fractions. ADH activity and ALDH activity of SFMM were 177.0% and 167.4% at 10 mg/ml, respectively. ${\alpha}$-Glucosidase inhibitory activity of SFMH increased in a dose-dependent manner and was about 94.1% at 2 mg/ml. Elastase inhibitory activity was 93.2% at 2 mg/ml. These results revealed that S. fulvellum extracts have strong antioxidant and alcohol dehydrogenase activities and ${\alpha}$-glucosidase inhibitory activity, suggesting that S. fulvellum extracts have potential as a source of natural products for health and beauty.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.766-773
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• 2013

In this study, white bread was prepared with Shinan seomcho powder (SSP). Different amounts of SSP were tested (2, 4, 6 and 8%) to determine the optimal amount. The samples and a control were compared for quality characteristics, including pH, total titratable acidity, specific volume, baking loss, moisture content, water activity, color, textural characteristics, external and internal surface appearances, and sensory qualities. As the SSP increased, the total titratable acidity of the dough decreased (pH increased), and a decreased specific volume and baking loss was observed as well. However, the total titratable acidity and pH of the bread did not show significant differences among the samples. The moisture content was highest at a substitution level of 8%, and increased with increasing SSP contents. The crumb L value, a value, and resilience decreased with increasing SSP, whereas the crumb b value and hardness increased. Color, flavor, softness and overall acceptability were highest for the control group and were lowest for the 8% group. This likely reflects the high value of a grassy flavor, green tea taste, bitterness, astringency, and off-flavor at addition level of 8%. As a results, the optimum amount of SSP to add for baking bread would be 2~4%.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.85-95
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• 2020

According to the standard guidelines of design flood (MLTM, 2012; MOE, 2019), the design flood is calculated based on past precipitation. However, due to climate change, the frequency of extreme rainfall events is increasing. Therefore, it is necessary to analyze future floods' volume by using climate change scenarios. Meanwhile, the standard guideline was revised by MOE (Ministry of Environment) recently. MOE proposed modified Huff distribution and new CN (Curve Number) value of forest and paddy. The objective of this study was to analyze the change of flood volume by applying the modified Huff and newly proposed CN to the probabilistic precipitation based on SSP and RCP scenarios. The probabilistic rainfall under climate change was calculated through RCP 4.5/8.5 scenarios and SSP 245/585 scenarios. HEC-HMS (Hydrologic Engineering Center - Hydrologic Modeling System) was simulated for evaluating the flood volume. When RCP 4.5/8.5 scenario was changed to SSP 245/585 scenario, the average flood volume increased by 627 ㎥/s (15%) and 523 ㎥/s (13%), respectively. By the modified Huff distribution, the flood volume increased by 139 ㎥/s (3.76%) on a 200-yr frequency and 171 ㎥/s (4.05%) on a 500-yr frequency. The newly proposed CN made the future flood value increase by 9.5 ㎥/s (0.30%) on a 200-yr frequency and 8.5 ㎥/s (0.25%) on a 500-yr frequency. The selection of climate change scenario was the biggest factor that made the flood volume to transform. Also, the impact of change in Huff was larger than that of CN about 13-16 times.

• Resources Recycling
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• v.19 no.6
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• pp.43-50
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• 2010

The crisis of energy gives rise to the growing concerns over continuing uncertainty in the energy market. Under these circumstances, there are also increasing interests on coals. In particular, Low Rank Coal (LRC) is receiving gradual attentions from green industry. But due to is high moisture content range from 30 - 60%, drying process has to be preceded before being utilized as power plant. In this study drying kinetics of LRC is induced by using a fixed-bed reactor. The drying kinetics was evaluated in from of the particle size, the inlet gas temperature, the drying time, the gas velocity, and the LID ratio. The consideration of the reynold's number was taken for correction of gas velocity, particle size and LID was taken for correction of reactor diameter, packing height of coal. As being seen as characteristic of drying coal, it can be found that fixed-bed reactor can contributed to active drying of free water. In this sense, it could be considered that phase boundary reaction is appropriate mechanism.

• Journal of Sericultural and Entomological Science
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• v.49 no.1
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• pp.18-23
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• 2007

The importance of genetic resources conservation and utilization for economy and the health and well-being of societies in general is recognized all over the world. Mulberry genetic resources contain many natural components and are considerable resource for functional sericulture. We carried out antioxidative capacity analysis of mulberry leaves that were collected from Korea and some of foreign countries and preserved in the greenhouse. The mean antioxidant capacity of 34 accessions was 892.30nmol(ascorbic acid equivalent). Also we evaluated fruity characteristics and selected 4 accessions as breeding resources for the production of mulberry fruit. To investigate the effect of tea on antioxidative capacity, five kinds of tea(coffee mix, green tea added brown rice, mulberry leaf tea, Polygonatum odoratum tea and black tea added lemon) were selected and analyzed. Their's antioxidative capacity were 2,531.01nmol, 1,867.42nmol, 1,053.72nmol, 292.71nmol and 188.91nmol, respectively. The antioxidative capacity of drinking water soaked with mulberry leaf showed 891.96nmol.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.130-138
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• 1987

The effects of light and storage conditions on the germination of Oenothera lamarckiana were investigated. Germination was induced by red light, but inhibited by green, blue or infrared. No germination occurred in the dark. Radicle was more photosensitive than other parts of the seed. The rate of germination was proportional to increase in Light intensity ranging from 10 to 3000 Lux. Photosensitivity occurred 6 hrs after water imbibition of air-dried seeds. Maximum photosensitivity was detected 1-2 days after seeding under the light condition at 300 Lux. Germination was almost completed 3 days after seeding. When seeds stored in the chilling and wetting condition were kept at constant temperature in the dark, they germinated well. Air-dried seeds, however, didn't germinate. Whereas, the seeds which kept at alternating temperature had the tendency that seeds stored at room temperature (25$^{\circ}C$) germinated better than those stored at low temperature (4$^{\circ}C$).