• Molecular & Cellular Toxicology
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• v.2 no.4
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• pp.251-256
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• 2006

The exploration of genes which expressions are changed by exposure to ecotoxicants or pollutants can provide the important information about the reaction mechanisms in the body as well as adaptation to exterior stimulus or environmental changes. Also they can be developed as biomarkers for the detection of environmental pollution. Differential display polymerase chain reaction (DD-PCR) technique has been usefully used to hunt the clones which expressions are up-regulated or down-regulated by exterior changes and this study aimed to search for those clones in diesel oil-exposed rockfish (Sebastes schlegeli) using DD-PCR. The RNA isolated from liver of 20 ppb diesel oil-exposed rockfish was used for screening of the differentially displayed genes and total 44 differentially expressed genes (DEG) are detected then their nucleotide sequences were analyzed. The present data provided the general information about the effect of diesel oil contamination on marine organism and further more the primary step in development of new biomarkers for marine environmental pollution or ecotoxicological stresses.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.2
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• pp.83-94
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• 2009

Environmental pollution becomes a serious problem in urban areas. Moreover, densely constructed strictures can be problematic to cities due to the rising temperature they cause as well as the increasing accumulation of air pollutants they generate by interrupting airflow. In order to improve residential amenity, it is necessary to improve the thermal environment by preserving wind corridors. To do so requires consideration to important aspects such as building arrangement, scale, vegetation, and land cover, which all have an effect on wind corridors. In this study, a typical arrangement-complex, which is the primary form of housing in Korea, was selected as a case ENVI-met. As a result of empirical analysis, the optimal apartment-complex arrangement that is most suitable for mitigating urban heat-islands phenomenon was determined, The outcome of this study can be utilized as a planning technique for apartment-complex construction in consideration to type of buildings, scale of buildings, and land cover.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1515-1528
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• 2017

The gastrointestinal (GI) tract, including the rumen and the other intestinal segments of cattle, harbors a diverse, complex, and dynamic microbiome that drives feed digestion and fermentation in cattle, determining feed efficiency and output of pollutants. This microbiome also plays an important role in affecting host health. Research has been conducted for more than a century to understand the microbiome and its relationship to feed efficiency and host health. The traditional cultivation-based research elucidated some of the major metabolism, but studies using molecular biology techniques conducted from late 1980's to the late early 2000's greatly expanded our view of the diversity of the rumen and intestinal microbiome of cattle. Recently, metagenomics has been the primary technology to characterize the GI microbiome and its relationship with host nutrition and health. This review addresses the main methods/techniques in current use, the knowledge gained, and some of the challenges that remain. Most of the primers used in quantitative real-time polymerase chain reaction quantification and diversity analysis using metagenomics of ruminal bacteria, archaea, fungi, and protozoa were also compiled.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.246-247
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• 2010

This paper deals with the water treatment of the leachate from sewage filled ground by a pulsed power technology. Leachate from sewage filled ground should be treated below regulation level of COD in order to prevent environmental pollution and usually treated by a chemical method. Among the pollutants mixed in the leachate, chemical compounds of benzene series are known to be difficult to break down, and need to use high cost treat methods. The treatment of the benzene compounds by high power pulsed power supply was studied. For the high-rate, cost-effective treatment of leachate, pulsed power supply should have high repetition rates and require switching devices of long lifetime. In order to meet the demands of the above condition, pulsed power generator based on semiconductor switches using IGBTs as primary switches were developed. The experimental results verified that benzene compounds can be treated effectively by high voltage electric pulses, and this fact indicates that the treatment method by pulsed power source is a promising substitute.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.454-458
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• 2007

Nonpoint source (NPS) pollution is a serious problem causing the degradation of soil and water quality. Concentrated overland flow is the primary transport mechanism for a large amount of NPS pollutants from hillslope areas to downslope areas in a watershed. In this study, a soil erosion model, nLS model, to identify transitional overland flow regions (i.e., ephemeral gully head areas) was developed using the kinematic wave overland flow theory. Spatial data, including digital elevation models (DEMs), soil, and landcover, were used in the GIS-based model algorithm. The model was calibrated and validated using gully head locations in a large agricultural watershed, which were identified using 1-m aerial photography. The model performance was better than two previous approaches; the overall accuracy of the nLS model was 72 % to 87 % in one calibration subwatershed and the mean overall accuracy was 75 to 89 % in four validation subwatersheds, showing that the model well predicted potential transitional erosion areas at different watersheds. However, the user accuracy in calibration and validation was still low. To improve the user accuracy and study the effects of DEM resolution, finer resolution DEMs may be preferred because DEM grid is strongly sensitive to estimating model parameters. Information gained from this study can improve assessing soil erosion process due to concentrated overland flow as well as analyze the effect of microtopographic landscapes, such as riparian buffer areas, in NPS control.

• Environmental and Resource Economics Review
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• v.22 no.1
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• pp.3-29
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• 2013

The purpose of this study is to estimate consumer preferences on hybrid cars and electric cars by employing a choice experiment reflecting the various market conditions, such as different projected market shares of green vehicles and $CO_2$ emission regulations. Depending on different market scenarios, we examine as to which attribute and individual characteristic affect the preferences of potential consumers on green vehicles and further, forecast the potential market shares of green cars. The primary results, estimated by a conditional logit and panel probit models, indicate that sales price, fuel cost, maximum speed, emission of air pollutants, fuel economy, and distance between fuel stations can significantly affect consumer's choice of environment-friendly cars. The second finding is that the unique features of electric cars might better appeal to consumers as the market conditions for electric cars are improved. Third, education, age, and gender can significantly affect individual preferences. Finally, as the market conditions become more favorable toward green cars, the forecasted market shares of hybrid and electric vehicles will increase up to 67% and 14%.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1133-1140
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• 2002

The growth and extent of the local pressure field at any point is of primary importance as it supplies the driving force for the local wind circulation which causes a medium-range transport of air pollutants. The local pressure field is produced by the variation of temperature in the lower layers of the atmosphere, and is called the thermal wave. The thermal wave is influenced by the difference in the diurnal variations between two regions with different surface condition, for example land and sea. This difference produces the land- and sea-breeze phenomenon, and brings corresponding variations in the form of the thermal wave. Daytime temperature over the inland area (Daegu) was higher than that of the coastal area (Busan). The temperature difference reached about 5~6$^{\circ}C$ in the late afternoon(30-31 May 1999). The low pressure system of Daegu was most fully developed at the time. In this study, we investigated the possibility of thermal low onset around Daegu in summer with an analytical model. The topography effect was neglected in the model. We could predict a thermal low-pressure of about 3.4hPa at Daegu with wide flat land surface, when the inland area is about 6K warmer than the coastal area temperature. The pressure decrease is somewhat less than the observed value(4~5 hPa).

• Journal of the Korean Society of Combustion
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• v.9 no.1
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• pp.11-17
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• 2004

The purposes of this study are to analyze nitrogen oxides(NOx) formation mechanism and to reduce abnormal NOx emissions in gas turbines. Industrial gas turbines emissions have potential to negative affect to the atmosphere in many different ways such as photochemical smog, acid rain and global warming. In conventional gas turbine combustors, one of the main pollutants such as nitrogen oxide(NOx) species, are principally formed from combustion process of fuel with oxygen in the primary combustion zone, and their emission levels are highly depend on peak temperatures in the combustor. In order to examine the characteristics and the effect of NOx formation, we used gas turbine of which commercial operating in Korea. From the examination, it has been found that NOx emissions are relatively high at low load(output) and during combustion mode change. Also, the effect of Air/Fuel ratio was considered. As the Air/Fuel ratio was increased in Lean-Lean mode, the NOx emission was decreased. The results of this study indicated that NOx emission levels are highly depend on peak temperature and pressure of combustion process in the combustor.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.65-73
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• 2011

The fibrous raw materials in packaging-grade paper production in Korea were mainly obtained from waste paper. The use of recycled paper has both positive and negative impacts in papermaking process. The primary positive impacts are the environmental protection and manufacturing cost reduction, and the negative impacts are the quality reduction in paper quality and the accumulation of heavy metals and other pollutants in wet- and dry-end process. This study was carried out to consider the optimum acid decomposition system with the highest recovery rate for the analysis of heavy metals in packaging-grade paper. The open digestion system using Kjeldahl apparatus and the closed digestion system using microwave oven for decomposing the organic materials in paper were compared. In both open and closed digestion method, the combination of nitric acid, hydrochloric acid and hydrogen peroxide showed higher recovery rate than using only nitric acid alone because the presence of Cl- ions in hydrochloric acid stabilizes ligand formation with metal ions. KOCC was observed to have the highest heavy metal content among the recycled paper samples. The heavy metal contents decomposed with the closed digestion system were relatively higher than with open digestion system.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.1
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• pp.9-20
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• 2019

The primary objective of this study was to analyze the delivery ratio using Hydrological Simulation Program - Fortran (HSPF) in Okdong-cheon watershed. Model parameters related to hydrology and water quality were calibrated and validated by comparing model predictions with the 8-day interval filed data collected for ten years from the Korea Ministry of Environment. The results indicated that hydrology and water quality parameters appeared to be reasonably comparable to the field data. The pollutant delivery loads of the watershed in 2015 were simulated using the HSPF model. The delivery ratios of each subwatershed were also estimated by the simple ratio calculation of pollutant discharge load and pollutant delivery load. Coefficients of the regression equation between the delivery ratio and specific discharge were also computed using the delivery ratio. Based on the results, multiple regression analysis was performed using the discharge and the physical characteristics of the subwatershed such as the area. The equation of delivery ratio derived in this study is only for the Okdong-cheon watershed, so the larger studies are needed to apply the findings to other watersheds.