• Journal of the Korean Society of Food Culture
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• v.8 no.3
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• pp.249-255
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• 1993

To minimize the waste amount of surface layer kochujang during aging, the effects of the three finishing methods(nothing, salt scatering and Polyethylene film on the kochujang surface) and sunning(conventional aging method) or nonsunning aging(cap covering) on water content, redness and spreadability, film forming yeast occurance and salinity of surface layer kochujang during 120 days aging were investigated. In the case of sunning aging, film forming yeast was not visually found on the surface. The surface layer kochujang was so low spreadability(zero) and very high salinity(18-30%) that could not eat. However, the aging method after PE-film covering on the kochujang surface, and then cap covering(nonsunning) was very effective in keeping of soundness of surface layer kochujang without film forming yeast growth on the surface kochujang, especially was greatly effective in keeping of redness, moderate moisture content and spreadability. The PE-film and cap covering aging were effective in prevention of water evaporation and $CO_2$ release, and in accumulation of ethanol and organic acids between the PE-film and surface layer of kochujang.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1300-1307
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• 1999

Supercritical fluid extraction was applied to recycling triglyceride from used shortening. Used shortening and its fractions were analyzed with high performance size exclusion chromatography for their composition in triglycerides, polymer and low molecular weight compounds. Conjugated diene value and color of the fractions were also measured with a UV spectrophotometer and a colorimeter, respectively. Pressure and temperature ranges employed were $15{\sim}30$ MPa and $40{\sim}60^{\circ}C$, respectively. Concentration of fat in supercritical (SC) $CO_2$ ranged from $0.3\;X\;10^{-3}{\sim}7.4\;X10^{-3}(g\;fat/g\;CO_2)$. An exponential relation between concentration of fat in SC $CO_2$ and density was observed. Color of the extracts was light yellow which was very close to that of the fresh shortening. Low molecular weight compounds were preferentially concentrated in the initial fraction, while polymer was extracted in the final fraction. Conjugated diene value of the initial fractions was clearly lower than that of feed. It increased sharply as the polymer content in the fraction became significantly large.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.482-488
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• 1997

Copper recovery from waste water of electronic industry has been conducted effectively in a fluidized bed reactor. Initial concentration of copper in the waste water, liquid flow rate in the reactor, reaction temperature and time and current density between the cathode and anode in the reactor have been selected as operating variables. The effects of operating variables on the recovery of copper have been studied. It has found that the copper resolved in the waste water can be recovered continuously by means of a fluidized bed reactor The recovery of copper decreased with an increase in the initial concentration of copper in the waste water, while it increased with increasing reaction time and current density, however, it exhibited its maximum value with the variations of liquid flow rate and reaction temperature. The optimum reaction condition to maintain the copper recovery around 85% is as follows ; $X_o=3wt%$, $U_L=0.5cm/s$, $T=25^{\circ}C$, $I=7A/dm^2$ and t=2hrs within this experimental condition.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.689-697
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• 2020

Hazardous and noxious substances (HNS) may cause maritime incidents during marine transportation, which are liable to lead to a large amount of spillage or discharge into the sea. The damage to the marine environment caused by the HNS spill or discharge is known to be much greater than the damage caused by oil spill. Particularly dangerous is HNS, which is deposited or buried in the seabed, as it can damage the organisms that live on, in, and near the bottom of the sea, the so-called "benthos," forming the benthic ecosystem. Therefore, it is vital that the HNS deposited on the seabed be recovered. In order to do so, procedures and equipment are required for accurate detection, stabilization treatment, and recovery of HNS in subsea sediment. Thus, when developing a mechanical recovery system, the performance requirements should be selected using performance indices, and the conceptual design of the mechanical recovery system should be based on performance requirements decided upon and selected in advance. Therefore, this study was conducted to arrive at a conceptual design for a mechanical recovery system for the recovery of HNS deposited on the seabed. In the design of the system, based on the fundamental scenario, the method of suction foundation with the function of self enclosing was adopted for recovering the HNS sediment in the subsea sediment. The mechanical recovery system comprises the suction foundation, pollution prevention, a pump system, control system, monitoring device, location information device, transfer device, and tanks. This conceptual design is expected to be reflected and used in the basic design of the components and shapes of the mechanical recovery system.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.353-362
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• 2015

Platform screen door (PSD) installed at underground subway station has reduced the safety accident, but it may cause poor air ventilation condition due to the isolated exhaust duct in the subway tunnel area. In this study, the additional ventilation system was suggested, which can be installed at a void space (i.e., storage room under stairs) of platform in order to improve efficiency of air ventilation rate. Exhausted air from platform was directed to underneath of platform and joined with existing ventilation duct of train exhaust system (TES). One subway station in Seoul city was selected to predict the effectiveness of the suggested lower exhaust system by using the computational fluid dynamics (CFD) analysis. The predicted mean age of air was decreased by 16.5% which proves the improvement of air ventilation efficiency when the suggested lower exhaust system was applied.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.83-91
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• 2012

Quorum sensing (QS) is a cell-to-cell communication system, which is used by many bacteria to regulate diverse gene expression in response to changes in population density. Bacteria recognize the differences in cell density by sensing the concentration of signal molecules such as N-acyl-homoserine lactones (AHL) and autoinducer-2 (AI-2). In particular, QS plays a key role in biofilm formation, which is a specific bacterial group behavior. Biofilms are dense aggregates of packed microbial communities that grow on surfaces, and are embedded in a self-produced matrix of extracellular polymeric substances (EPS). QS regulates biofilm dispersal as well as the production of EPS. In some bacteria, biofilm formations are regulated by c-di-GMP-mediated signaling as well as QS, thus the two signaling systems are mutually connected. Biofilms are one of the major virulence factors in pathogenic bacteria. In addition, they cause numerous problems in industrial fields, such as the biofouling of pipes, tanks and membrane bioreactors (MBR). Therefore, the interference of QS, referred to as quorum quenching (QQ) has received a great deal of attention. To inhibit biofilm formation, several strategies to disrupt bacterial QS have been reported, and many enzymes which can degrade or modify the signal molecule AHL have been studied. QQ enzymes, such as AHL-lactonase, AHL-acylase, and oxidoreductases may offer great potential for the effective control of biofilm formation and membrane biofouling in the future. This review describes the process of bacterial QS, biofilm formation, and the close relationship between them. Finally, QQ enzymes and their applications for the reduction of biofouling are also discussed.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.99-104
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• 2010

The purpose of this study is to develop Sewage Treatment Plant that treat sewage which occurred in ship using fixed media method and to consider applicable to the Pilot Scale device of the STP regulations in MLTM(Ministry of Land, Transport and Maritime Affairs) and MEPC(Marine Environment Protection Committee). In test results, pH geometric mean was 7.68, $BOD_5$(Biochemical Oxygen Demand) geometric mean was 7.28 mg/l, $COD_{cr}$(Chemical Oxygen Demand) geometric mean was 48.39 mg/l, TSS(Total Suspended Solid) geometric mean was 18.00/l, Residual chlorine geometric mean was 0.19 mg/l, and E. coli geometric mean was 1CFU/100 ml. In addition, about 97.4% of $BOD_5$ was reduced, the $COD_{cr}$ reduction averaged 96.4%and the TSS reduction averaged 97.6%. STP have been determined by the MLTM and MEPC regulation of the marine pollution prevention equipment for performance testing product.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.3
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• pp.132-137
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• 2008

The average concentrations of COD and copper in the livestock sludge are $930,726{\pm}380.801$ mg/kg and $679{\pm}341$ mg/kg, respectively. Due to the high concentrations, dumping to the sea of the sludge could pose potential adverse effects to the marine environment. On the contrary, it could have economic advantages on land as the energy of biogas generated by decomposition of organisms and the compost in case of the sludge of good quality with the abundant nitrogen and phosphorus. Nevertheless, the amount of livestock sludge dumped to the sea in Korea increased sharply from 51,000 $m^3$ in 1997 to 2,745,000 $m^3$ in 2005. And also it had the high proportion of 27% in total amount of waste dumped into the sea (7,451,000 $m^3$) in 2007. It might cost between 20,000 won and 33,000 won to dump to the sea of the sludge. In comparison, it might cost 20,000 won to com- post the sludge. And its purification treatment even might cost just 10,000 won. It means that the disposal of the sludge at sea is the most expensive method to deal with the sludge, but ranchers, who engage in the livestock industry, still prefer the disposal at sea to the other methods on land such as the compost and purification treatment. In this article, therefore, we would analyze various factors in the ranchers' preference for the disposal of the sludge at sea, and then we could suggest some legal improvements to prevent and reduce pollution of the sea.

• Analytical Science and Technology
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• v.26 no.4
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• pp.276-286
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• 2013

This study was performed to investigate the contents characteristics of hazardous oil wastes and wastes of liquid fuels from different industrial process. In order to establish a hazardous waste list, samples of various industrial discharge have been analyzed for 16 non-regulated inorganic hazardous substances (i.e., Cu, Pb, Cd, CN, Hg, As, T-Cr, $Cr^{6+}$, Sb, Ni, F, V, Ba, Zn, Be, Se). In more detail, hazardous waste samples including waste hydraulic oils, waste engine, gear and lubricating oils, waste insulating and heat transmission oils, bilge oils, oil/water separator contents processing were collected from 37 workplaces and analyzed. We observed that the most of the inorganic substances exceeded the proposed criteria in many samples. Especially the concentration of Sb in heat transmission oil, bilge oil and gear & lubricating oils were ranged from 6 to 419 mg/kg whereas the proposed criteria is 50 mg/kg. The assessment result of hazardous waste in Korea according to the EWC showed that the out of 24 processes, 16 belongs to absolute entry and 8 belongs to mirror entry. In conclusion, we expect the outcome of this study to align the classification system of hazardous waste management in South Korea with international legislations, and consequently contribute to reduce environmental pollution as well as health risks by toxic wastes.

• Journal of Conservation Science
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• v.33 no.2
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• pp.121-130
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• 2017

The currently used wax agents for preserving outdoor metal structures, despite their advantages, have disadvantages such as low endurance and reliability. These wax agents are easily damaged by acid rain, dust, moisture in the air, yellow dust, and air pollutants, resulting in corrosion within a short period after the initial conservation treatment. In addition, aged wax can also exhibit changes in the color or gloss, and also give a sense of difference in the surface. Given these existing problems, it is necessary to develop improved materials for metal preservation. Therefore, this study analyzed the characteristics and applications of the existing wax coating agents in order to identify their disadvantages and to develop a better material for metal preservation. In this regard, this study developed a perilla oil based compound wax and conducted experiments to test its endurance. The new compound wax agent was exposed to outdoor and acid rain conditions: it showed four times and 1.5 times the endurance of the existing wax agents in outdoor and acid rain conditions, respectively. In addition, the new agent seems to be more durable and protective as evidenced by the chromaticity, polish maintenance, and contact angle results. Further, although it is 1.3-1.8 times thicker than the existing agents, the new agent shows a more even surface. Based on these findings, it can be concluded that the new compound wax agent based on perilla oil is a better alternative to the existing was coating agents.