• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1591-1604
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• 2023

In ocean color remote sensing, atmospheric correction is a vital process for ensuring the accuracy and reliability of ocean color products. Furthermore, in recent years, the remote sensing community has intensified its requirements for understanding errors in satellite data. Accordingly, research is currently addressing errors in remote sensing reflectance (R_rs) resulting from inaccuracies in meteorological variables (total ozone, pressure, wind field, and total precipitable water) used as auxiliary data for atmospheric correction. However, there has been no investigation into the error in R_rs caused by the variability of the water vapor profile, despite it being a recognized error source. In this study, we used the Second Simulation of a Satellite Signal Vector version 2.1 simulation to compute errors in water vapor transmittance arising from variations in the water vapor profile within the GOCI-II observation area. Subsequently, we conducted an analysis of the associated errors in ocean color products. The observed water vapor profile not only exhibited a complex shape but also showed significant variations near the surface, leading to differences of up to 0.007 compared to the US standard 62 water vapor profile used in the GOCI-II atmospheric correction. The resulting variation in water vapor transmittance led to a difference in aerosol reflectance estimation, consequently introducing errors in R_rs across all GOCI-II bands. However, the error of R_rs in the 412-555 nm due to the difference in the water vapor profile band was found to be below 2%, which is lower than the required accuracy. Also, similar errors were shown in other ocean color products such as chlorophyll-a concentration, colored dissolved organic matter, and total suspended matter concentration. The results of this study indicate that the variability in water vapor profiles has minimal impact on the accuracy of atmospheric correction and ocean color products. Therefore, improving the accuracy of the input data related to the water vapor column concentration is even more critical for enhancing the accuracy of ocean color products in terms of water vapor absorption correction.

• Journal of the Korean earth science society
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• v.29 no.2
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• pp.128-139
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• 2008

Intercomparison among the three radiative transfer models (RTMs) which have been used in the studies for COMS, was carried out on the condition of aerosol-laden atmospheres. Also the role of aerosols in the atmospheric radiation budget was analyzed. The results (hereafter referred to as H15) from Halthore et al.'s study (2005) were used as a benchmark to examine the models. Aerosol Radiative Forcing (ARF) values from the three RTMs, calculated under two conditions of Aerosol Optical Thickness (AOT=0.08, 0.24), were systematically underestimated in comparison to H15 in the following shortwave components; 1) direct and diffuse irradiance at the surface, 2) diffuse upward fluxes at the surface and the top of the atmosphere, and 3) atmospheric absorbance. The ARF values for the direct and diffuse fluxes at the surface was $-10{\sim}-40Wm^{-2}$. The diffuse upward values became larger with increasing both AOT and Solar Zenith Angle (SZA). Diffuse upward/downward fluxes at the surface were more sensitive to the SZA than to the atmospheric type. The diffuse downward values increased with increasing AOT and decreasing SZA. The larger AOT led to surface cooling by exceeding the reduction of direct irradiance over the enhancement of diffuse one at the surface. The extinction of direct solar irradiance was due mainly to water vapor in tropical atmospheres, and to both ozone and water vapor in subarctic atmospheres. The effect of water vapor in the tropics was $3{\sim}4$ times larger than that of the ozone. The absorbance values from the three RTMs agree with those from H15 within ${\pm}10%$.

• KSBB Journal
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• v.19 no.2
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• pp.93-97
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• 2004

We investigate the effect of enzyme pretreatment using protease, carbohydrase, and lipase on improvement of sludge treatment efficiency by measuring SCOD and TCOD. The enzyme-pretreatment increases SCOD of excess sludge. In addition, the amount of sludge reduction during digestion, in terms of SCOD and TCOD, are enhanced by enzyme-pretreatment. Among pretense, carbohydrase, and lipase, pretense showed the best enhancement of the sludge treatment efficiency. Sludge digestion followed by ozone and enzyme treatments showed more effective sludge treatment when compared with ozone treatment alone. Therefore, we expect that enzyme pretreatment can be used as a useful tool for enhancing the sludge treatment efficiency.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.464-472
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• 2020

We suggest a hydroponic cultivation system combined with a plasma generator to investigate the changes in the growth and functional substance content of lettuces during the cultivation period. Lettuce seedlings of uniform size were planted in semi-DFT after seeding for 3 weeks, and the plasma-activated water was intermittently operated for 1 hour at an 8 hours cycle for 4 weeks. Lettuces grew with or without plasma-activated water with the nutrient solution in hydroponics culture systems. Among the reactive oxygen species generated during plasma-activated water treatment, brown spots and necrosis appeared in the individuals closer to the plasma generating device due to O₃, and there was no significant difference in the growth parameters. While the rutin and total phenolic content of the lettuce shoot grown in the nutrient solution were higher than that of the plasma-activated water, epicatechin contents in plasma-activated water were significantly greater than the nutrient solution. However, in the roots, all kinds of secondary metabolites measured in this work, rutin, epicatechin, quercetin, and total phenolic contents, were significantly higher in the plasma-activated water than the control. These results were indicated that the growth of lettuce was decreased due to the reactive oxygen species such as ozone in the plasma-activated water, but the secondary metabolites in the root zone increased significantly. It has needed to use this technology for the cultivation of root vegetables with the modified plasma-activated water systems to increase secondary metabolite in the roots.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1295-1305
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• 2021

Satellite-derived ocean color products are required to effectively monitor clear open ocean and coastal water regions for various research fields. For this purpose, accurate correction of atmospheric effect is essential. Currently, the Geostationary Ocean Color Imager (GOCI)-II ground segment uses the reanalysis of meteorological fields such as European Centre for Medium-Range Weather Forecasts (ECMWF) or National Centers for Environmental Prediction (NCEP) to correct gas absorption by water vapor and ozone. In this process, uncertainties may occur due to the low spatiotemporal resolution of the meteorological data. In this study, we develop water vapor absorption correction model for the GK-2 combined GOCI-II atmospheric correction using Advanced Meteorological Imager (AMI) total precipitable water (TPW) information through radiative transfer model simulations. Also, we investigate the impact of the developed model on GOCI products. Overall, the errors with and without water vapor absorption correction in the top-of-atmosphere (TOA) reflectance at 620 nm and 680 nm are only 1.3% and 0.27%, indicating that there is no significant effect by the water vapor absorption model. However, the GK-2A combined water vapor absorption model has the large impacts at the 709 nm channel, as revealing error of 6 to 15% depending on the solar zenith angle and the TPW. We also found more significant impacts of the GK-2 combined water vapor absorption model on Rayleigh-corrected reflectance at all GOCI-II spectral bands. The errors generated from the TOA reflectance is greatly amplified, showing a large error of 1.46~4.98, 7.53~19.53, 0.25~0.64, 14.74~40.5, 8.2~18.56, 5.7~11.9% for from 620 nm to 865 nm, repectively, depending on the SZA. This study emphasizes the water vapor correction model can affect the accuracy and stability of ocean color products, and implies that the accuracy of GOCI-II ocean color products can be improved through fusion with GK-2A/AMI.

• Food Science and Preservation
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• v.17 no.3
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• pp.405-409
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• 2010

Surface cleaning is both essential and troublesome when a consumer seeks to eliminate soil attached to the surface of fresh ginseng because all ginseng purchased in the market is covered with soil, reflecting the post-harvest situation. To facilitate ginseng use at home, a fresh-cut type of ginseng is required. As a first step toward production of such ginseng, several washing and dipping treatments were investigated with respect to surface cleaning and reduction of microbial populations on fresh ginseng. In terms of microbial distribution on the surface of fresh ginseng, higher levels of viable bacteria (6.63 log CFU/each) and fungi (5.12 log CFU/each) were present on the rhizome head than on other regions of the root. Of the washing treatments tested, hand-brushing was effective for surface cleaning and to reduce microorganism levels on fresh ginseng, but use of a high-pressure water spray followed by hand-brushing was optimally effective. To further reduce the levelsof microorganisms on the surface of fresh ginseng after washing, additional dipping treatments in 70% (v/v) ethanol and electrolyzed acidic water (at pH 2.3) were somewhat effective but showed no significant differences compared with other dipping treatments tested, including a 3 ppm ozone solution, a 200 ppm sodium hypochlorite solution, or hot water at $50^{\circ}C$.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.800-805
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• 2016

Rapid growth in nanotechnologies promises novel benefits through the exploitation of their unique industrial applications. However, as the production volume of nanomaterials increases, their unintentional exposure to the environment has been occured. Potential impacts of nanoproducts on the environment can be evaluated in the life cycle assessment (LCA). LCA is the systematic analysis of the resource usages and emissions over the life time from the primary resources to the moment of disposal. In this study, we performed LCA for fabrication processes of superhydrophilic oil/water separator using nano-$TiO_2$. $TOTAL^{TM}$ freeware was used to analyze for all fabrication processes, and 6-environmental impact factors (resource depletion, climate change, ozone depletion, acidification, eutropication, and photochemical oxidation) were introduced. In addition, the use of nano-$TiO_2$ in the fabrication of superhydrophilic oil/water separator was actively contributed to the environmental impact factors, compared to the bulk-$TiO_2$.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.518-524
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• 2013

This study investigated the degradation of taste-and-odor compounds and toxins using dielectric barrier discharge plasma. The degradation of taste-and-odor compounds was conducted on geosmin and 2-methyl isoborneol (2-MIB), and the toxins investigated were microcystin-LR (MC-LR), microcystin-RR (MC-RR), microcystin-YR (MC-YR) and anatoxin-a. Largely depending on the type of gas fed to the plasma reactor, the degradation efficiencies of the taste-and-odor compounds decreased in order of oxygen (100%) > dry air (96%) > nitrogen (5%) for geosmin and in order of oxygen (100%) > dry air (94%) > nitrogen (2%) for 2-MIB on the basis of 150 s reaction time. This result suggests that the oxidative reactive species generated during plasma treatment, especially long-lived ozone, are mainly responsible for the degradation of these compounds. When using oxygen as the feed gas, geosmin and 2-MIB were totally degraded within 150 s, microcystins within 10 s, and anatoxin-a within 30 s. It was found that the taste-and-odor compounds and toxins were degraded more rapidly in real lake water than in distilled water.

• Journal of Animal Environmental Science
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• v.12 no.3
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• pp.133-140
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• 2006

The climate of stall significantly influences on animal production ability. High concentration of ammonia gas, $CO_2$ and lots of dust are found in modern densely raising stall system, as results, they provide a negative influence on animal and farmer health, and production ability. Therefore, it is necessary to keep clean the inside air of stall to increase the productivity. An air cleaner of wet type, consisting of a fan, a motor, rotating discs, a dust collector, a water bowl, an ozone generator etc, has been developed to clean the stall air. The work principle is that the inside air is sucked through the fan, and the rotating discs make water into fineness spray and blow into the stall. The rest water flows down to the dust collector. In the present study, we measured the dust, ammonia gas, odor, temperature and humidity in a swine stall that were installed two wet air cleaners with 700 fattening swine with On-mode and Off-mode of wet air cleaners. The dust measure was divided into 3 categories, TSP, $PM_{10}$, and $PM_{2.5}$. In summer, the TSP in on-mode were maximum $0.259mg/m^3$ and minimum $0.128mg/m^3$, and the average was $0.195mg/m^3$. These are comparable to the data from Off-mode stall that maximum $0.308mg/m^3$, minimum $0.139mg/m^3$, and average $0.277mg/m^3$. However, $PM_{10}$ and $PM_{2.5}$ showed any significant differences between the tests. The concentrations of ammonia gas in Off-mode stall were maximum 13.8 ppm and minimum 5.9 ppm, and the average was 8.47 ppm. However in On-mode stall the ammonia gas concentrations were maximum 10.5 ppm and minimum 5.5 ppm, and the average was 7.63 ppm. The concentration of ammonia gas in On-mode was 10% in average lower than off-mode stall. Odor was measured by olfactometer. In the Off-mode stall, the odor unit were maximum 420 $Ou/m^3$ and minimum $300\;OU/m^3$, and the average was $367\;OU/m^3$, but in the On-mode stall the odor unit were maximum $330\;OU/m^3$ and minimum $210\;OU/m^3$, and the average was $253\;OU/m^3$. Odor removal efficiency was about 31% in On-mode stall.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.281-287
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• 2011

BACKGROUND: According to Korean regulations, bottled waters (BWs) can not be treated with chemical disinfectants like chlorine, so UV and ozone disinfection is applied. During the past several years, chemicals were detected in some BWs, and the public was concerned about the safety of BWs. METHODS AND RESULTS: Mineral waters were stored for 180 days at $25^{\circ}C$ and $50^{\circ}C$, tested acetaldehyde and formaldehyde by HPLC. When mineral waters were put in a PET bottles, the formaldehyde level ranged from 5 to $66{\mu}g/L$ during 180 days at $50^{\circ}C$. While the acetaldehyde level ranged from 31 to $221{\mu}g/L$, it was low than $16{\mu}g/L$ in glass bottle. CONCLUSION(s): This result showed that formaldehyde and acetaldehyde were detected higher in PET bottles than glass bottles, these also increased depending on the time of storage. Concentration of formaldehyde and acetaldehyde could be significantly influenced by the time of storage and temperature.