• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.276-276
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• 2022

Estuarine dams are constructed for securing freshwater resources, flood control, and improving upstream navigability. However, their impact on estuarine currents, stratification, and sediment fluxes is not well understood. To develop a general understanding, an idealized modeling study was carried out. Tide and river forcing were varied to produce strongly stratified, partially mixed, periodically stratified, and well-mixed estuaries. Each model ran for one year. Next, the models were subject to the construction of an estuarine dam and run for another year. Then, the pre- and post-dam conditions were compared. Results showed that estuarine dams can amplify the tidal range and reduce the tidal currents. The post-dam estuaries tended to be a salt wedge during freshwater discharge and a bay during no freshwater discharge. For all estuaries, the estuarine turbidity maximum moved seaward, and the suspended sediment concentrations tended to decrease. In terms of sediment flux mechanisms, the estuarine dam increased the seaward river runoff for cases with strong river, and increased the landward tidal pumping for cases with strong tides.

• Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.23-34
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• 2024

While scientific information on the spatial variation of soda lake Microalgae is important to limnological studies, little information was reported from the Ethiopian Rift Valley Lake, Lake Chitu. This study aimed to understand the spatial distribution of the dominant Microalgae taxa in Lake Chitu, Ethiopia. The collection of samples and in situ measurements of some physico-chemical parameters were recorded at three sites for one cycle in November 2021. Fourteen species or genera of Microalgae were identified. Among those, Bacillariophyta were the most important with regard to species abundance and the rarest in species richness. Cyanophyta were the second-most important group in terms of species richness and rarity. Comparatively, all microalgae taxa were rare at both the anthropogenic areas (AA) and the flooding area (FA), which could be mainly due to intensive human and animal intervention and associated with extreme turbidity. Among Cyanophyta, Chroococcus minutus, Microcystis aeruginosa, and Spirulina platensis/fusiformis were predominant at both AA and FA, revealing their adaptation to less clear water and pollution. But S. platensis/fusiformis attained the highest abundance at the FA, indicating their preference for water in a highly nutrient-enriched area. We concluded that the spatial variation of microalgae diversity in relation to water quality parameters has implications for the importance of microalgae as a baseline indicator of water quality assessment tools in lakes.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.596-603
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• 2019

This study involved the production of specialty lager beers supplemented with Korean red ginseng extracts or Bokbunja (Korean black raspberry, Rubus coreanus Miquel) juice. The effects of the Korean red ginseng extracts or Bokbunja juice on the specific gravity, pH, yeast viability, free amino nitrogen content, reducing sugar content, color, alcohol content, turbidity, and sensory evaluation were evaluated. The alcohol content of the beers containing the extracts or juice were within the standard alcohol amounts (3.63-4.0%, v/v). The pH values of the three samples containing Bokbunja juice were lower than that of the control values. The sensory evaluation showed that the addition of Bokbunja juice was superior to the ginseng extracts, and the optimal addition time was before or after the secondary fermentation. These data indicate that the flavor and odor of the Bokbunja juice are more persistent than that of the ginseng extracts.

• Membrane and Water Treatment
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• v.9 no.5
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• pp.335-342
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• 2018

Micelle-Enhanced Ultrafiltration (MEUF) is a membrane separation processes that improving ultrafiltration process with the formation of micelles of the surface active agents. Surface active agents are widely used to improve membrane processes due to the ability to trap organic compounds and metals in the treatment of industrial waste water. In this study, surface active agents are used to improve micelle-enhanced ultrafiltration (MEUF) to reduce chemical oxygen demand (COD), total dissolved solid (TDS), turbidity and clogging the membrane in dairy wastewater treatment. Three important operational factors (anionic surface active agent concentration, pressure and pH) and these interactions were investigated by using response surface methodology (RSM) and Box-Behnken design. Results show that due to the concentration polarization layer and increase the number of Micelles; the anionic surface active agent concentration has a negative effect on the flux and has a positive effect on the elimination of contamination indices. pH, and the pressure have the greatest effect on flux. On the other hand, it could be stated that these percentages of separation are in the percentages range of Nano-filtration (NF). While MEUF process has higher flux than NF process. The results have been achieved at lower pressure while NF process needs high pressure, thus making MEUF is the replacement for the NF process.

• Journal of environmental and Sanitary engineering
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• v.10 no.1
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• pp.106-125
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• 1995

Recently, in accordance with elevation of life style and economics, the public demand became increasingly concerned about drinking water quality. Without an adequate supply of safe water, healthy and comfortable life could not exist. Therefore, the purpose of this study is to provide the guidelines and the basic informations to enable supply of clean, tasty and healthy drinking water acceptable for various demands. We analyzed the quality of tap water, mineral water, purified tap water using home tap water purifier. And we researched on the sense of the public complaint over the tap water. We proposed several items relating to the comfortableness of water quality and the target value. Also we presented a case of water supply system for purity and the points at problem The items and target value are as follows 1. turbidity : not more than 1 degree 2. dry residue : $30~200{\;}mg/{\ell}$ 3. hardness : $10~100mg/{\ell}$ 4. free carbon dioxide : not more than $20mg/{\ell}$ 5. $KMnO_{4}$ consumption not more than $3mg/{\ell}$ 6. odor threshold not abnormal 7. residual chlorine : not more than $0.4mg/{\ell}$ 8. water temperature' not more than $20^{\circ}C$ 9. manganese : not more than $0.01mg/{\ell}$ 10. iron : not more than $0.02mg/{\ell}$ 11. aluminum : not more than $0.1mg/{\ell}$

• Journal of Environmental Science International
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• v.16 no.2
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• pp.227-232
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• 2007

Water pollution in enclosed water bodies such as lake and river has become a serious problem over the world. Domestic wastewater is responsible for more than 60 % pollution load in public water area in Korea. Effluent of the treated domestic wastewater at low removal level is abundantly fed rivers and lakes and thus be an serious cause of lake pollution. Therefore, effective implement of domestic wastewater treatment in basin of lake and river must be prepared. The septic tank is one of the effective domestic wastewater treatment equipment and used in individual treatment for a unit of household, The purpose of septic tank as biological treatment system is simultaneously to remove BOD, T-N, T-P and reduce turbidity from influent. Accordingly, the appropriate control of functional microorganisms is important subject for the establishment of stability and economy of the biological treatment method. Especially, microanimals as a high-ranked microorganisms of food-chain are important, because microanimals control the other microorganisms especially various bacteria and effect on function of treatment. Therefore, it is necessary that functional predator like rotifers are attached in wastewater treatment process. In this study, the methods for attachment high density the rotifer to and improvement of transparency in the effluence by a dense rotifer was examined using laboratory scale biological treatment reactor simulated septic tank and real one.

• Culinary science and hospitality research
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• v.12 no.2 s.29
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• pp.206-221
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• 2006

To establish an optimum formula for processing wet noodles with steam-dried Hizikia fusiformis flour(SHF), it was incorporated into wheat flour by the ratio of 0, 1, 3, 5, 10 and 20% based on a flour weight. Application of 2% mehthylcelluose(MC) to improve the texture of noodles mixed with SHF was also attempted. Evaluation was performed on the dough rheology and wet noodle quality, such as cooking characteristics, mechanical texture properties, sensory value and shelf-life. Water absorption rate of the composite flour increased linearly as the content of SHF increased from 1% to 10%, and noodle sheet-formation was also acceptable in the same content level. The weight and volume of cooked noodles were decreased, and turbidity of soup was, if exceeding more than 5% of SHF, increased constantly. However, these problems could be remarkably resolved in SHF plus 2% MC. Texture profile analysis of cooked noodles showed an increase of hardness, gumminess, and chewiness up to 5% SHF. The results of sensory evaluation showed that cooked noodles containing 5% SDF were acceptable as much as wheat four noodles in terms of color, texture, taste and flavor. Based on cooking properties, rheological and sensory evaluation, addition of 5% SHF plus 2% MC was suggested to be suitable for making wet noodles, of which the shelf-life was estimated to be 8 days at $5^{\circ}C$.

• KSBB Journal
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• v.14 no.5
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• pp.523-527
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• 1999

A naturally luminescent bacterium, Photobacterium phosphoreum was stored in 2.5% NaCl solution at 2$0^{\circ}C$, 4$^{\circ}C$, -2$0^{\circ}C$ and -7$0^{\circ}C$ for 30 days. In vivo luminescence and concentrations of total and culturable cells were determined by luminometer, spectrophotometer and dilution plate counting, respectively. When stored at 4$^{\circ}C$ and 2$0^{\circ}C$, concentrations of cells were rapidly decreased as a result of cell lysis, leading to adrop in turbidity and cultured counts. The bioluminescence of cells stored at 4$^{\circ}C$ was maintained until 12 days while those of cells starved at other temperatures decreased to background level within 3 days. Following incubation of stored cells in fresh liquid medium, activities of viable cells increased throughout storage period excepting cells stored at 2$0^{\circ}C$. Changes in bioluminescence intensity following addition of 2.5% NaCl solution markedly showed in cells stored at -2$0^{\circ}C$ and -7$0^{\circ}C$ and increased to maximum 8 fold.

• ALGAE
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• v.22 no.4
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• pp.261-271
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• 2007

The variations of species compositions, standing crops and seasonal succession of phytoplanktons including Cyanophyceae, Chlorophyceae and Bacillariophyceae were investigated with physico-chemical elements of water to clarify the causes of water bloom according to the water depth in the Lake Unmun. The increased amounts of turbidity, T-N, T-P and SS originated from heavy rain and typhoon in the middle of June provoked to produce phytoplanktons. In July and August, the dominant species was Peridinium sp., while the subdominant species was Microcystis aeruginosa. In October, Aulacoseira distans was dominant and Asterionella formosa was subdominant. During the period of water shortage, the concentrated pollutants caused the decrease of precipitation, the long stagnation time of water body and the mixed pollutants by upwelling as decreasing water temperature could accelerate the water bloom. The preventives to decrease microalgal generation should be controled by the stagnation time of water body by increasing outflow to intercept water bloom such as ulacoseira sp. in October as well as summer.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.703-705
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• 2003

A comparison was made between the chlorophyll a and suspended solid (SS) retrievals from OSMI and SeaWiFS sensor to chlorophyll a and SS values determined with the standard method during the NFRDI's research cruises. The percentage of organic and inorganic materials from the SS was calculated to study the contribution of turbid water in the northern part of the East China Sea. The open sea waters in the Kuroshio regions of the East China Sea showed relatively higher concentration of volatile SS. However, towards the northwestern part of the East China Sea, the situation became much more optically different with the non-volatile SS from the Yangtze river and the sea bottom sources in the sea in winter and spring seasons. Furthermore, in order to indirectly detect low salinity water with high turbidity, which related to the Yangtze river using remote sensed data from the satellites, a comparison between the results of the band ratio(nLw 490nm/nLw 555nm) of SeaWiFS (OSMI) and the distribution of low salinity around the Jeju Island was presented.