• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.51-56
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• 2009

Safety and quality assessment systems are very important in manufacture, storage, transportation, and handling of hazardous materials(hazmat) to prevent hazmat disasters. At present, hazardous materials exist everywhere in our daily lives with various forms of plastics, household products of cleaning and washing detergents, fertilizers or petroleum-related products. However, hazardous materials are dangerous substances when they are released to human or environment. Hazardous materials become very widely used substances in the age of oil-based industrial economy. The Korean Ministry of Environment (KMOE) describes about one hundred thousand types of chemicals are produced and used worldwide. Over four hundred new chemicals are introduced in every year. A crucial question for the Korean hazardous material management may have been raised: Will you be safe from hazardous material incidents? The gas leak disaster at Union Carbide's Bhopal, India in 1984 that made over 6,400 people killed and 30,000 to 40,000 people seriously injured is the representative case for the safety of hazmat. Korea becomes vulnerable to hazmat disaster due to the development of high-tech industry. Thus, the risk assessment system is required to Korea for transferring abandoned hazmat management systems to self-correcting safety systems. This research analyzed characteristics of various hazmat incidents applying statistical analysis methods including frequency analysis or analysis of category data to hazmat incidents for ten years. All of three analyses of category data indicate the significance of causality between hazmat incident site groups and seasons, regional groups, and incident casualty groups.

• Journal of Energy Engineering
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• v.10 no.3
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• pp.195-205
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• 2001

A great deal of energy is necessary with emission of lots of wastewater in dyeing and finishing process, but heat recovery from wastewater is not introduced since is technology is not developed yet. In order to obtain the method utilizing hot water produced by heat source, that is, dyeing wastewater it was investigated the characteristics of dyeing and finishing process and energy basic unit. Energy basic unit of polyester/cotton (T/C), polyester/rayon (T/R) and polyester dyeing process are higher than that of the other process. The average quantity of wastewater for each dyeing company is 20,470 ton/month, the average temperature of wastewater is about 41$^{\circ}C$. Because the SS solution of wastewater in polyester dyeing process is lower than that of the other process, the effect of corrosion in heat recovery system is low. Since the energy price for 1000 kcal produced by vapor compression heat pump is presumed to be 22.50 won, it is found to be very economic heat recovery system, and its payback is 2.09 years for the factory with LNG boiler.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.704-716
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• 2012

This paper provides a detailed account of pilot testing conducted at South Lake Tahoe (California), the Ddukdo (Seoul) water treatment plant (WTP) and the Bokjung (Seongnam) WTP between February, 2010, and February, 2012. The objectives were first, to characterize the reactions of ozone with hydrogen peroxide (Peroxone) for Han River water following sand filtration, second to determine empirical ozone and hydrogen peroxide doses to remove a taste-and-odor surrogate 2-methylisoborneol (MIB) using an advanced oxidation process (AOP) configuration and third, to determine the optimum dosing configuration to reduce residual ozone to a safe level at the exit of the process. The testing was performed in a real-time plant environment at both low- and high seasonal water temperatures. Experimental results including ozone decomposition rates were dependent on temperature and pH, consistent with data reported by other researchers. MIB in post-sand-filtration water was spiked to 40-50 ng/L, and in all cases, it was reduced to below the specified target level (7 ng/liter) and typically non-detect (ND). It was demonstrated that Peroxone could achieve both MIB removal and low effluent ozone residual at ozone+hydrogen peroxide doses less than those for ozone alone. An empirical predictive model, suitable for use by design engineers and operating personnel and for incorporation in plant control systems was developed. Due to a significant reduction in the ozone reaction/decomposition at low winter temperatures, results demonstrate the hydrogen peroxide can be "pre-conditioned" in order to increase initial reaction rates and achieve lower ozone residuals. Results also indicate the method, location and composition of hydrogen peroxide injection is critical to successful implementation of Peroxone without using excessive chemicals or degrading performance.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.522-526
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• 2006

To investigate the characteristics of rainwater in Daegu area, parameters such as pH, electrical conductivity, TOC, TIC and TC were analyzed on 34 samples from January to December 2005. Results revealed that higher values were measured in winter than in summer. Furthermore samples that originated from industrial and commercial areas had higher chemical concentrations and conductivity as compared with those from residential and reference areas. Seldom acid-rain occurrence was recorded(27.2%) as compared with non-acid precipitation(72.8%) incidence. Also higher organic carbon fraction(TOC) was detected(72.5%) than inorganic form(TIC)(27.5%) in terms of component ratio with TC. During frequent rainfalls, the concentration of chemicals was decreased to a degree. Conversely, lower rate of rainfall gave out higher chemical values. Thereby the improvement of air qualify in 2005 compare with 2003 report was influenced by the environment authorities' efforts to reduce air pollutions and various factors by the depression of the region's economy.

• Korean Journal of Plant Resources
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• v.19 no.4
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• pp.459-470
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• 2006

This study was carried out objectively to analyze the distributing flora for the conservation of natural environment and to construct the database in Mt. Joryeong, Chungcheongbuk-do, Korea. The period of survey was from November, 2004 to September, 2005, and the routes were A (Recreation $forest{\sim}Shinseon-bong$), B $(Shinseon-bong{\sim}Mapae-bong)$, C(Joryeong 3rd $gateway{\sim}Mapae-bong$), and D $(Yongseong-gol{\sim}Gitdae-bong)$. The vascular plants were summarized as 341 taxa; 85 families, 219 genera, 299 species, 36 varieties, and 6 forma. The rare and endangered plants designated by Korea Forest Service were 3 taxa; Paeonia japonica, Viola albida, and Rhododendron micranthum. The Korean endemic plants were 9 taxa; Cephalotaxus harringtonia, Salix caprea, Deutzia coreana, Spiraea prunifolia for. simpliciflora, $Lespedeza{\times}tomentella$, Vaccinium koreanum, Salvia chanroenica, Weigela subsessilis, and Cirsium setidens. And in the results of survey on resource plants, we confirmed 171 taxa of ornamental plants (50.1%), 222 taxa of edible plants (65.1%), 237 taxa of medicinal plants (69.5%) and 146 taxa of other useful plants (42.8%).

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.242-252
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• 2016

A process-based ecosystem model, BIOME-BGC, was applied to simulate seasonal and inter-annual dynamics of carbon and water processes for potential evergreen needleleaf forest (ENF) biome in Korea. Two simulation sites, Milyang and Unljin, were selected to reflect warm-and-dry and cool-and-wet climate regimes, where massive diebacks of pines including Pinus densiflora, P. koraiensis and P thunbergii, were observed in 2009 and 2014, respectively. Standard Precipitation Index (SPI) showed periodic drought occurrence at every 5 years or so for both sites. Since mid-2000s, droughts occurred with hotter climate condition. Among many model variables, Cpool (i.e., a temporary carbon pool reserving photosynthetic compounds before allocations for new tissue production) was identified as a useful proxy variable of tree carbon starvation caused by reduction of gross primary production (GPP) and/or increase of maintenance respiration (Rm). Temporal Cpool variation agreed well with timings of pine tree diebacks for both sites. Though water stress was important, winter- and spring-time warmer temperature also played critical roles in reduction of Cpool, especially for the cool-and-wet Uljin. Shallow soil depth intensified the drought effect, which was, however, marginal for soil depth shallower than 0.5 m. Our modeling analysis implicates seasonal drought and warmer climate can intensify vulnerability of ENF dieback in Korea, especially for shallower soils, in which multi-year continued stress is of concern more than short-term episodic stress.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.381-389
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• 2023

Vibrio vulnificus, the most fatal waterborne and foodborne pathogens of 50% fatality rate in the world, is common in seawater and occurs particularly in warmer months. In this study, we investigated the toxin genes using reverse transcription-polymerase chain reaction (RT-PCR), antibiotic resistance status using Vitek, and genetic characteristics using pulsed-field gel electrophoresis (PFGE) of different V. vulnificus strains isolated from the Jeju Island seawater, distribution fishery products, and fish tanks. We examined a total of 487 samples and isolated a total of 46 strains (including overlapping strains) of V. vulnificus, 44 strains from seawater and 1 strain each from fishery products and fish tank. We detected toxin gene vvhA in all 46 strains and rtxA, viu in 8 strains (17.4%) and 9 strains (19.6%) strains, respectively. Antibiotic resistance tests indicated 100% resistance to cefoxitin antibiotics. The PFGE analysis of the 46 strains identified a total of 6 types showed 100% homology and the degree of similarity was 81.3-98.0%; however, there were no similarity between the regions and samples. These results indicate that V. vulnificus isolated from the seawater, fishery products, and fish tanks should be continuously monitored as cases of food poisoning caused by V. vulnificus with toxin genes have been reported in Jeju Island.

• Journal of the Korean earth science society
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• v.41 no.2
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• pp.95-110
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• 2020

Comparisons between two different surface temperatures from high-resolution ECMWF ReAnalysis 5 (ERA5) and Automated Synoptic Observing System (ASOS) observations were performed to investigate the reliability of the new reanalysis data over South Korea. As ERA5 has been recently produced and provided to the public, it will be highly used in various research fields. The analysis period in this study is limited to 1999-2018 because regularly recorded hourly data have been provided for 61 ASOS stations since 1999. Topographic characteristics of the 61 ASOS locations are classified as inland, coastal, and mountain based on Digital Elevation Model (DEM) data. The spatial distributions of whole period time-averaged temperatures for ASOS and ERA5 were similar without significant differences in their values. Scatter plots between ASOS and ERA5 for three different periods of yearlong, summer, and winter confirmed the characteristics of seasonal variability, also shown in the time-series of monthly error probability density functions (PDFs). Statistical indices NMB, RMSE, R, and IOA were adopted to quantify the temperature differences, which showed no significant differences in all indices, as R and IOA were all close to 0.99. In particular, the daily mean temperature differences based on 1-hour-averaged temperature had a smaller error than the classical daily mean temperature differences, showing a higher correlation between the two data. To check if the complex topography inside one ERA5 grid cell is related to the temperature differences, the kurtosis and skewness values of 90-m DEM PDFs in a ERA5 grid cell were compared to the one-year period amplitude among those of the power spectrum in the time-series of monthly temperature error PDFs at each station, showing positive correlations. The results account for the topographic effect as one of the largest possible drivers of the difference between ASOS and ERA5.

• Korean Journal of Environmental Agriculture
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• v.33 no.2
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• pp.86-102
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• 2014

BACKGROUND: According to the types of human interference, there are various plants that have strong vitality and ability to breed in the dry field. Recently, climate change alters the geographical distribution and phenology of the plant species. So, we need to understand present occurrence pattern and ecological characteristics of these plants. METHODS AND RESULTS: The plant species data were obtained from 8 regions in Jeolla-do. Flora investigation was done from May 2013 to September 2013. Habitat type of dry field in Jeolla-do was classified into 3 types (inside of dry field: IDF, embankment around the end of a dry field: EDF, levee slope of dry field: LS). The vascular plants of study area were listed 296 taxa which contain 68 families, 203 genera, 244 species, 43 varieties and 9 forms. The vascular plants of three different habitat types were IDF 174 taxa, EDF 249 taxa and LS 136 taxa. The occurrence rate of Therophyte was arranged by the order of IDF(67.6%), EDF(51.9%), LS(54.3%). Naturalized rate was analysed as IDF 27.9%, EDF 21.0%, LS 18.6%. Urbanization index was analysed as IDF 11.8%, EDF 13.7%, LS 10.0%. CONCLUSION: With these results, we found that three habitat types were ecological difference affected by the human impacts. Also, we found environmental indicators through the ecological characteristics of flora for the type of habitat of dry field. These indicators will help assess the agriculture environmental variability and the floral change according to the climate change in dry field.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.208-220
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• 2019

The seasonality of leaf fall has important implications for understanding the response of trees' phenology to climate change. In this study, we quantified the leaf fall pattern with a model to estimate the timing and speed of leaf litter according to species and considered the nutrient use strategy of canopy species. In the autumns of 2015 and 2016, leaf litter was collected periodically using 36 litter-traps from the deciduous forests in Gwangneung and sorted by species. The seasonal leaf fall pattern was estimated using the non-linear regression model of Dixon. Additionally, the resorption rate was calculated by analyzing the nitrogen concentration of the leaf litter at each collection time. The leaf litter generally began in early October and ended in mid-November depending on the species. At the peak time (T50) of leaf fall, on average, Carpinus laxiflora was first, and Quercus serrata was last. The rate of leaf fall was fastest (18.6 days) for Sorbus alnifolia in 2016 and slowest (40.8 days) for C. cordata in 2015. The nitrogen resorption rates at T50 were 0.45% for Q. serrata and 0.48% for C. laxiflora, and the resorption rate in 2015 with less precipitation was higher than in 2016. Since falling of leaf litter is affected by environmental factors such as temperature, precipitation, photoperiod, and $CO_2$ during the period attached foliage, the leaf fall pattern and nitrogen resorption differed year by year depending on the species. If we quantify the fall phenomena of deciduous trees and analyze them according to various conditions, we can predict whether the changes in leaf fall timing and speed due to climate change will prolong or shorten the growth period of trees. In addition, it may be possible to consider how this affects their nutrient use strategy.