• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.41-46
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• 1994

This study was undertaken to clarify the effect of killing methods on physical and rheological changes of plaice, Paralichthys olivaceus muscle at early period after death. Plaices killed by the four different methods(1. spiking at the brain instantly. 2. drowning in air. 3. dipping in 1,000ppm ethylaminobenzoate dissolved sea water as an anesthetic. 4. electrifying in sea water.) were stored at $5^{\circ}C$, and the rigor-index and breaking strength through storage were monitored. The longest onset time of rigor-mortis and full rigor was in the samples killed by dipping in sea water with dissolved anesthetic among all samples, where rigor-mortis began at 20hrs after killing and maximum tension was attained after 56hrs. However, in the cases of plaice electrified in sea water or drowned in air, the onset of rigor-mortis began just after killing and maximum tensions were attained after 9hrs and 13hrs, respectively. The level of breaking strength in the muscle of fish killed by spiking the brain instantly was $950.30{\pm}50.23g$, immediately after killing. The value and time reached around the maximum breaking strength for each of the samples were $1,230.60{\pm}30.32g$ and Ohr (immediately after killing) for samples killed by electrifying in sea water, $1,235.83{\pm}35.37g$ and 2.5hrs for drowning samples, $1,186.29{\pm}55.90g$ and 10hrs for spiking samples, and $1,189.67{\pm}50.32g$ and 15hrs for samples dipped in anesthetic, respectively. From the results above, it could be concluded that electrification in sea water is the most effective method in accelerating rigor-mortis and shortening times of reaching the maximum breaking strength of fresh plaice flesh of all the killing methods at early periods after death, whereas dipping in sea water treated with anesthetic was the most effective way in delaying those changes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.2
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• pp.181-188
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• 1989

The present study has been carried out to investigate the effect of Bactokil(made from didecyldimethyl ammonium chloride isopropanol and water) and Taipet-F (made from natural vitamin E, L-ascorbic acid, glyceride and gallic acid) on retarding lipid oxidation in boiled-dried anchovy. To process boiled-dried anchovy, boiled anchovy dried in cabinet drier $(dry-bulb\;temperature\;40^{\circ}C)$ for 1 hour were fronted with the Bactokil, the Taipet-F and mixture of Bactokil and Taipet-F, respectively. Anchovy fronted with chemicals were redried for 8 hours, packed in polyethylene film bag, and then stored at room temperature $(24{\pm}3^{\circ}C)$. These products were compared with control(untreated with chemicals) during storage. The changes in volatile basic nitrogen of each product was negligible during storage. The thiobarbituric acid and peroxide values of each product increased up to 10 days of storage, and then decreased. In color value of each product, L value increased, while n, b and ${\bigtriangleup}E$ values decreased during storage. The changes in brown pigment formation of each product increased up to final stage of storage. From the results of chemical analysis and sensory evaluation, the product treated with Taipet-F(0.5%, v/v) was the most effective on retarding lipid oxidation of the boiled -dried anchovy, followed by the product treated withthe mixture of Bactokil (0.04%, v/v) and Taipet-F (0.5%, v/v), the product treated with Bactokil(0.04%, v/v) and control, in the order named.

• Food Science and Preservation
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• v.23 no.5
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• pp.605-613
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• 2016

The quality and shelf life of sliced root of Platycodon grandiflorum (Doraji) treated by ozon-microbubble-heat shock (OMH) were investigated by combining modified-atmosphere packaging [MAP, ($50%O_2+15%CO_2+35%N_2$)]. The study was based on microbiological (total viable bacteria, fungi, Enterobacteriaceae and coliforms numbers), physicochemical and sensory changes. OMH treatment was effective in reducing microbial populations of the sliced Doraji, especially Enterobacteriaceae and coliforms reduced by 2 log CFU/g. However OMH-MAP treatment remained the aerobe and fungi numbers. Regarding the color, OMH-MAP delayed the change of Hunter $b^*$ and the sliced Doraji by OMH-MAP treatment exhibited lower decrease of flavor and overall acceptability compared to those by polypropylene packaging after tap water treatment (Control). The OMH and $50%O_2+15%CO_2$ MAP treatment gave better sensory quality and extended shelf-life for sliced Doraji (~3 days longer shelf-life than Control). Flavor was significantly related to overall acceptability at both Control and OMH-MAP, whereas total coliforms prevalence was associated with overall acceptability at only OMH-MAP. Therefore microbubble-heat shock treatment may improve microbial safety and sliced Doraji by OMH treatment can stored under $50%O_2+15%CO_2$ treatment for up to 7 days. Thus, OMH and MAP treatment may be used in maintaining the storage quality and marketability of sliced Doraji.

• Food Science and Preservation
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• v.11 no.3
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• pp.331-335
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• 2004

This study was carried out to improve quality of minimally processed lettuce with various treatments. The treatments for preventing enzymatic browning were using different chemical immersion solutions and controlling microbial growth were using chlorine, electrolyzed water, and organic acid. The solution with ascorbic acid 1$\%$ and citric acid 1 $\%$ showed a positive effect on antibrowning of minimally processed lettuce. In the inhibition of microorganisms growth, 200 ppm NaCIO solution was more effective than fermented pollen solution and Na-dichloroisocyanurate solution. In electrolyzed water system, no-diaphragm system showed inhibitory effect of microorganisms growth. Also, total microorganisms count of minimally processed lettuce with ascorbic acid and citric acid solution was lower by about 4 log cycle after 4 days storage at l0$^{\circ}C$.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.6-12
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• 2005

Contamination of soils and groundwater by leakage of petroleum compounds from underground storage tanks (USTs) has become great environmental issues. Conventional methods such as soil vapor extraction (SVE) used for the remediation of unsaturated soils contaminated with volatile organic compounds might not be applied for the removal of semi-volatile organic compounds such as diesel fuels and PCBs, which have low volatility and high hydrophobicity. The objective of this study is to develop a hot air injection method to remove semi-volatile compounds. Additionally, operation parameters such as temperature, air flow rate, and water content are evaluated. Experimental results show that diesel ranged organics (DROs) are removed in the order of volatility of organic compounds. As expected, removal efficiency of organics is highly dependent on the temperature. It is considered that more than $90\%$ of organic contaminants whose carbon numbers range between 17 and 22 can be removed efficiently by the hot air injection-extraction method (modified SVE) over the $100^{\circ}C$. It is also found that increased air flow rate resulted in high removal rate of contaminants. However, air flow rate over 40 cc/min is not effective for the operation aspects, due to mass transfer limitation on the volatilization rate of the contaminants. The effect of the water content on the decane removal is minimal, but some components show large dependence on the removal efficiency with increasing water content.

• Food Science and Preservation
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• v.10 no.3
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• pp.297-301
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• 2003

The hardness of corrugated packaging box decreased during storage period because of high humidity. Therefore, the strength-decreasing factor of corrugated packaging box had to be investigated to determine the compression strength of the corrugated packaging box. This study was conducted to define the characteristics of moisture absorption as well as compression strength of corrugated fiberboard. (1) The moisture content of the corrugated fiberboard was rarely influenced by the kinds of raw materials and water repellent. However, the moisture adsorption of the corrugated fiberboard was shown to be clearly affected by air temperature changes. (2) The moisture content of the corrugated fiberboard was significantly affected by relative humidity. The moisture adsorption of corrugated fiberboard was also greatly influenced by composition of raw materials rather than water repellent. The results indicated that the improvement of raw materials was more effective than the increase of water repellent of corrugated fiberboard to reduce the moisture adsorption of the corrugated fiberboard. (3) The vertical compression strength was significantly decreased with increasing relative humidity. The reduction rate of vertical compression strength was not charged with the increase of relative humidity, which was regardless of kinds of corrugated fiberboard. (4) For improving the strength of the corrugated packaging box, new technique should be found to develop better quality of raw materials. Moreover, the physical construction of corrugated packaging box should be clearly understood because the corrugated packaging box for the agricultural products was usually used for the circumstances of high humidity and low air temperature

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.64-71
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• 2019

In recent years, carbon dioxide ($CO_2$) bubbles emerged as the most widely applied material with the recycling of sequestrated storage to decrease global warming. Flotation using $CO_2$ as an alternative to air could be effective in overcoming the high power consumption in the dissolved air flotation (DAF) process. The comparison of DAF and DCF system indicated that, the carbon dioxide flotation (DCF) system with pressurized $CO_2$ only requires 1.5 ~ 2.0 atm, while the DAF system requires 3.0 ~ 6.0 atm. In a bid to understand the characteristics of particle separation, the single collector collision (SCC) model was used and a series of simulations were conducted to compare the differences of collision and flotation between $CO_2$ bubbles and air bubbles. In addition, laboratory experiments were sequentially done to verify the simulation results of the SCC model. Based on the simulation results, surfactant injection, which is known to decrease bubble size, cloud improved the collision efficiency of $CO_2$ bubbles similar to that of air bubbles. Furthermore, the results of the flotation experiments showed similar results with the simulation of the SCC model under anionic surfactant injection. The findings led us to conclude that $CO_2$ bubbles can be an alternative to air bubbles and a promising material as a collector to separate particles in the water and wastewater.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.395-405
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• 2021

When issuing forecasts and alerts for agricultural drought, the relevant ministries only rely on the observation data from the reservoirs managed by the Korea Rural Community Corporation, which creates gaps between the drought analysis results at the local (si/gun) governments and the droughts actually experienced by local residents. Closing these gaps requires detailed local geoinformation on reservoirs, which in turn requires the information on reservoirs managed by local governments across Korea. However, installing water level and flow measurement equipment at all of the reservoirs would not be reasonable in terms of operation and cost effectiveness, and an alternate approach is required to efficiently generate information. In light of the above, this study validates and calibrates the parameters of the TANK model for reservoir basins, divided them into groups based on the characteristics of different basins, and applies the grouped parameters to unmeasured local government reservoirs to estimate and assess inflow. The findings show that the average determinant coefficient and the NSE of the group using rice paddies and inclinations are 0.63 and 0.62, respectively, indicating better results compared with the basin area and effective storage factors (determinant coefficient: 0.49, NSE: 0.47). The findings indicate the possibility of utilizing the information regarding unmeasured reservoirs managed by local governments.

• Journal of the Korean Geotechnical Society
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• v.40 no.1
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• pp.29-37
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• 2024

In this study, recycled concrete aggregates (RCA) were treated in a 5-kg-scale prototype reactor with carbon dioxide (CO₂) to enhance their material quality and geotechnical performance. The aggregate crushing value (ACV) and California bearing ratio (CBR) were measured on untreated RCAs and CO₂-treated RCAs. After CO₂ treatment, the ACV decreased from 35.6% to 33.2%, and the CBR increased from 97.5% to 102.4%. The CO₂ treatment caused a reduction of fine particle generation and an increase in bearing capacity through carbonation. When CO₂ treatment was performed with mechanical agitation, which provided additional enhancement in mechanical quality, the ACV was reduced further to 30.3%, and the CBR increased to 137.7%. If upscaled effectively, the proposed CO₂ treatment technique would be an effective method to reduce carbon emissions in construction industries.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.795-802
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• 2013

According to the increase of impervious area due to the town development, the rate of infiltration generally lessens and that of runoff rises during wet weather events. And it is concerned that its impacts on water quality for the downstream water bodies due to the change of rainfall runoff patterns may also increase. To cope with these issues, LID (Low Impact Development) techniques which try to maintain the characteristics of rainfall runoff regardless of the town development have been introduced actively. However, the behaviors of each LID technique for rainfall runoff and pollutant loads is not understood sufficiently. In this study, considering the applications of some LID techniques, several sets of simulations using a distributed rainfall runoff model, SWMM-LID, have been conducted for D town whose development is progressing. As the results of the simulations, the rates of infiltration/storage have been decreased from 78% in the case before the town development to 15% after the development and increased again by 24% with LID techniques such as porous pavement, rain barrel and rain garden. The rates of runoff have been increased more than three times from 20% in the case before the development to 74% after the development, and they have also been decreased to 66% by the adoption of LID techniques. It has been simulated that porous pavement is more effective than others in the view point of the reduction of runoff and rain barrel is more attractive for the management of pollutant loads (TSS, BOD, COD, T-N and T-P). Therefore, if some LID techniques should be selected for the a new town, it could be concluded that some techniques with better infiltration functions are recommendable for the control of runoff, and ones with larger storage functions for the management of pollutant loads.