• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.20-26
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• 2016

The residence time measures the time spent by a water parcel or a pollutant in a given water body. So residence time of water is widely used as an indicator of how a substance will remain in an estuary and it is used to enable comparisons among different water bodies. To estimate residence time of particulate matters from land and aquaculture, EFDC that includes particle tracking model was applied to the Geoje Bay. Modelled average residence time was about 65 days in the inner part. It meant it takes about 2 months for substance from land and aquaculture to be transported to the outside of Geoje Bay. The results indicated that residence time varied spatially throughout Geoje Bay depending on tidal flushing and, in general conditions, tidal flushing exerts the greatest influence to the flushing of Geoje Bay. This reveals relationships between residence times of particulate matters and physical properties of the bay and Geoje Bay is vulnerable to water quality problem.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.268-272
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• 2005

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.2
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• pp.29-33
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• 2014

Active air flushing mini-pumps were installed in a rigid polypropylene container ($32cm{\time}23cm{\time}18cm$) containing 900 g of fresh green peppers for effectively controlling its $O_2$ concentration on real time basis to preserve the product quality. The performance of the constructed system was compared to that of the modified atmosphere (MA) container system with gas diffusion tube controlled in close/open cycles responding to real time $O_2$ concentration at 10 and $20^{\circ}C$. In the control logic, the $O_2$ concentration was programmed to be located exactly at 13% or stay in the range of 13-15%. The active air flushing system could control the $O_2$ concentration in the desired level or range at both temperatures, while the passive diffusion system could work only under the low temperature condition of $10^{\circ}C$. At higher temperature of $20^{\circ}C$, the passive diffusion system could not manage the produce respiration increased more highly than the gas transfer through the diffusion tube, resulting in too low $O_2$ concentration and too high $CO_2$ concentration which would be injurious to the green pepper. When tested at $20^{\circ}C$, the MA container system could preserve the green pepper better than the perforated air package in terms of weight loss, ascorbic acid and chlorophyll contents and firmness.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.9-24
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• 1997

Surfactant-aided in situ soil flushing has been proposed as an alternative for the expensive and time consuming 'pump and treat' technology in remediation of contaminated soil and groundwater Injected surfactants can effectively solubilize contaminants sorbed to the soil matrix or nonaqueous phase liquids(NAPLs) in residual saturation. The contaminants solubilized in groundwater are recovered and treated further. The theoretical background of the technology and the results of the field operations, mostly in the US. were summarized. In addition, the factors crucial to the successful application of the technology were discussed. Cost analyses and technical limitations in current applications were also discussed. In conclusion, it is likely that in situ surfactant flushing become a viable option for soil remediation in limited cases. Currently, further advances with respect to operation cost and to treatment efficiency are required for more extensive application of the technology. However, the current trends in soil remediation, specially the growing emphasis on risk based corrective action and natural attenuation, will increase the competitiveness of the technology. For example, removal of easily washable contaminants by short term soil flushing followed by long term monitoring and natural attenuation can greatly reduce the operation cost and time.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.79-84
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• 2016

A kimchi container actively controlling $CO_2$ concentration by timely flushing of $CO_2$ gas was structured and tested in its capability and effectiveness because high $CO_2$ concentration enhances the sensory flavor of the product. The inlet and outlet valves of $CO_2$ gas were programmed to open and close allowing synchronous vent/$CO_2$ flush according to the requirements of its dissolution in the contained kimchi. During the chilled storage, the headspace of container could be maintained at desired high $CO_2$ concentration providing the preferred kimchi in sensory quality compared to control of the conventional container. However, there was no significant difference between the high $CO_2$ container and control (container simply closed with air) in kimchi quality attributes of pH, titratable acidity, total viable bacterial count, Lactobacillus sp. count and Leuconostoc sp. count. The flow rate and time interval of $CO_2$ flushing need to be adjusted considering the kimchi amount, headspace volume and ripening time. The designed system has potential to be applied in refrigerator appliances in homes and food service industry.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.671-678
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• 1997

The objective was to evaluate method of feeding (free access or intubation), method of slaughter (carbon dioxide gas or barbiturate) and digesta flushing medium (distilled water or physiological saline), in the development of an ileal amino acid digestibility assay for 4 week-old broiler chickens. Three diets were used (commercial (C), semi-synthetic meat-and bone meal (MBM) or wheat (W)). For the coarser C and W diets but not for the MBM diet, feeding method had a significant effect on concentrations of chromium (Cr), nitrogen (N), acid detergent fibre (ADF) and neutral detergent fibre (NDF) in the crop contents at a set time after a meal. There appeared to be a selection of food particles under free-access feeding. For birds receiving the wheat diet there was an effect (p < 0.05) of sampling time after feeding on the concentrations of Cr, N, ADF and NDF/Cr in the crop contents. Flushing ileal digesta with distilled water or saline led to similar apparent ileal N digestibility coefficients. Birds given the MBM diet, and killed by inhalation of $CO_2$, had significantly (p < 0.05) lower apparent ileal N digestibility coefficients (73 versus 80%) than those killed by barbiturate overdose.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.1
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• pp.1-9
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• 2008

This study examined the effect of an electrokinetic-flushing remediation for a soil of a high permeability. The soil was sampled from the site around a research atomic reactor which had high hydro-conductivities due to a high content of sand in the soil. The flow rate of the washing reagent was fast at the beginning but it was reduced as time lapsed. In the case of using citric acid as a washing reagent, the flow rate was fastest, 78.7 ml/day. The removal efficiencies of $Co^{2+}$ and $Cs^+$ from a soil cell with acetic acid were the highest, which were 95.2% and 84.2% respectively. The soil waste-solution volume generated from the electrokinetic remediation was reduced to about 1/20 of that from the soil washing remediation. Meanwhile, the electrokinetic-flushing method enhanced the removal efficiencies of $Co^{2+}$ and $Cs^+$ from the soil by about 6% and 2% respectively, compared to those by the electrokinetic method. Consequently, it was found that the electrokinetic-flushing method was more effective for the remediation of a soil with a high permeability.

• Journal of Korea Water Resources Association
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• v.37 no.10
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• pp.857-868
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• 2004

Since the self-purification capacity of rivers in Korea is significantly controlled by environmental maintenance flow supplied by upstream reservoirs during drought season, it is obviously important to operate the river and reservoir systems considering not only water quantity aspect but also conservation of downstream water quality and ecosystem. In this study, an unsteady river water quality model KORIVl- WIN was developed as a tool for evaluating the impact. of reservoir operations on the downstream water quality. The model parameters were calibrated and verified using field data obtained in Geum River on September and October of 2002, respectively. Intensive data sampling was performed on November 22, 2003 to investigate the effect of a short-term flushing discharge of Daecheong Reservoir, which increased outflow from 30 $m^3$/s to 200 $m^3$/s for 6 hours, on downstream water quality. The model performance was evaluated by comparing simulated results with observed data including hydraulics, biochemical oxygen demand(BOD$_{5}$), nitrogen and phosphorus species during the flushing event. It showed very good performance in predicting the travel time of flushing flow and water quality variations of dissolved forms of nitrogen and phosphorus species, while revealed large deviations for BOD$_{5}$ possibly due to missing the effect of organic matters resuspension from river bottom sediment during the wave front passage.

• Membrane Journal
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• v.19 no.1
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• pp.7-18
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• 2009

In this study, we used the hybrid module that was composed of granular activated carbons (GAC) packing between module inside and outside of tubular ceramic microfiltration membrane for advanced drinking water treatment. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, modified solution was prepared with humic acid and kaolin. We were investigated effect of water-back-flushing time (BT) and water-back-flushing period (FT) to minimize membrane fouling and to enhance permeate flux (J) in the hybrid process, and tried to find the optimal operating conditions. As a result, resistance of membrane fouling ($R_f$) was slightly decreased according to increasing BT. Also, the shorter FT was the more effective to reduce $R_f$ and to enhance J because of frequent water-back-flushing. However, the optimal BT and FT conditions were 10 sec and 8 min respectively when operating costs were considered. Then, the optimal conditions derived from our experiments of modified solution were applied to lake water treatment. As a result, average treatment efficiencies of turbidity, $UV_{254}$ absorbance, and $COD_{Mn}$ were very high as 99.11%, 91.40% and 89.34%, respectively, but that of TDS was low as 30.05%.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.1
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• pp.65-70
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• 1998

To understand the caused for poor response to superovulation in water buffalo compared to crossbred cows, follicular events, before start of superovulation, during superovulation and after superovulation were compared. Follicular development was monitored a day before start of superovulation, daily upto superestrus and on the day of flushing. A real time B mode diagnostic instrument equipped with a linear array, 5 MHz transducer was used in five crossbred cows and five Murrah buffaloes. Crossbred cows yielded significantly (p < 0.01) higher number of corpora lutea than buffaloes (21 vs 10). The mean number of small size (2 to 5 mm); medium size (6 to 9 mm) and large size $({\geq}10mm)$ follicles, a day before start of superovulation were almost similar or even slightly higher in buffalo. Though initial shift in the mean number of follicles was higher in buffalo than cow, yet, from Day 2 to Day 3 of the treatment, the average increase in medium (3.2 vs 1.2) and large size (5.0 vs 2.0) follicles was higher in cows than buffaloes. The mean number of medium and large size follicles was 9.8 and 14.4 in cows and 6.4 and 7.6 in buffaloes. On the day of flushing, the number of large size follicle was more in buffaloes than cows, indicating the ovulation problem in this species. The major conclusion from this investigation was that, a day before start of superovulatory treatment, the number of small and medium size follicles was slightly higher in buffaloes, even then superovulatory response was better in cows, due to shift, recruitment and passage of follicles from smaller size to larger size from Day 2 of treatment. Ovulation problem in buffaloes was also responsible for lower superovulatory responses as revealed by the presence of higher number of large size follicles on the day of flushing.