간행물
한국환경과학회지 KCI 등재 Journal of Environmental Science International
- 발행기관 한국환경과학회
- 자료유형 학술지
- 간기 월간
- ISSN 1225-4517 (Print)2287-3503 (Online)
- 수록기간 1992 ~ 2023
- 주제분류 자연과학 > 자연과학일반 자연과학 분류의 다른 간행물
- 십진분류KDC 539DDC 628
권호리스트/논문검색
제27권 제8호 (2018년 8월) 10건
ORIGINAL ARTICLE
1.
2018.08
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Many chemically active species such as ·H, ·OH, O3, H2O2, hydrated e-, as well as ultraviolet rays, are produced by Dielectric Barrier Discharge (DBD) plasma in water and are widely use to remove non-biodegradable materials and deactivate microorganisms. As the plasma gas containing chemically active species that is generated from the plasma reaction has a short lifetime and low solubility in water, increasing the dissolution rate of this gas is an important challenge. To this end, the plasma gas and water within reactor were mixed using the air-automizing nozzle, and then, water-gas mixture was injected into water. The dissolving effect of plasma gas was indirectly confirmed by measuring the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the formation of OH radical) solution. The plasma system consisted of an oxygen generator, a high-voltage power supply, a plasma generator and a liquid-gas mixing reactor. Experiments were conducted to examine the effects of location of air-automizing nozzle, flow rate of plasma gas, water circulation rate, and high-voltage on RNO degradation. The experimental results showed that the RNO removal efficiency of the air-automizing nozzle is 29.8% higher than the conventional diffuser. The nozzle position from water surface was not considered to be a major factor in the design and operation of the plasma reactor. The plasma gas flow rate and water circulation rate with the highest RNO removal rate were 3.5 L/min and 1.5 L/min, respectively. The ratio of the plasma gas flow rate to the water circulation rate for obtaining an RNO removal rate of over 95% was 1.67 ~ 4.00.
2.
2018.08
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A Cultivation method to minimize the damage caused by high temperatures was studied by investigating the effects of groundwater cooling treatment on the growth, yield, and quality of strawberries. In the groundwater cooling treatment, the daily average temperature of the rhizosphere was reduced from 26.9°C to 24.9°C . The root length increased by 0.3–9.2 cm, depending on the cultivar and growth period. The leaf number, leaf area, leaf length, leaf diameter, and plant height also increased, especially in the cultivars ‘Seolhyang’ and ‘Maehyang’, resulting in higher fresh and dry weights. The number of fruit per plant increased from 7.7 to 12.5 in ‘Seolhyang’, and the fruit weight increased by 0.3 g in ‘Seolhyang’ and 1.3 g in ‘Maehyang’. The fruit hardness increased, but no significant difference in fruit coloration was observed. The sugar content of the fruit was improved by 0.2–0.3 °Brix. Therefore, groundwater cooling of the rhizosphere was effective in improving the growth and productivity of strawberries under abnormally high temperature conditions and can be considered a cost-efficient cooling system.
3.
2018.08
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Paddy-upland rotation system is one of the important cropping system for improving soil quality and crop productivity. we conducted to investigate the effect of paddy-upland rotation system on soil properties and crop productivity in reclaimed tidal land. The paddy-upland rotation could be effective to conserve soil water contents and prevent from salt damage when cultivating upland crops. The first two years of maize cultivation after rice cultivation could be effective to secure stable production. However, in case of soybean crop, the rotation effect might be lower than that of maize. In the first year, the yield of soybean was 214 kg/10a. In the second and third year, the yields of soybean decreased consecutively to 152, 123 kg/10a respectively. In this paper, it would be suggested that maize be cultivated for up to two years and soybean be cultivated for one year after rice crop grown in reclaimed tidal land. This study could be provide basic data of the physico-chemical properties applicable to paddy-upland rotation system at reclaimed tidal lands.
4.
2018.08
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The hydrochemistry of groundwater from 47 wells in the Chungwon area, Korea was analyzed to examine the occurrence of natural radionuclides like uranium and radon. The range of Electrical Conductivity (EC) value in the study area was 67∼1,404 μS/cm. In addition to the high EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from ND～178 μg/L (median value, 0.8 μg/L) and radon concentrations ranged from 80～12,900 pCi/L (median value, 1,250 pCi/L). Uranium concentrations in one well, that is 2.8% of the samples, exceeded 30 μg/L, which is the Maximum Contaminant Level (MCL) proposed by the US Environmental Protection Agency (EPA), based on the chemical toxicity of uranium. Radon concentrations in three wells, that is 6% of the samples, and one well, that is 2.8% of the samples, exceeded 4,000 pCi/L (AMCL of the US EPA) and 8,100 pCi/L (Finland’s guideline level), respectively. Concentrations of uranium and radon related to geology of the study area show the highest values in the groundwater of the granite area. The uranium and radon contents in the groundwater were found to be low compared to those of other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.
5.
2018.08
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The purpose of this study was to identify the characteristics of the home range and habitat use of Rhinolophus ferrumequinum individuals that inhabit urban areas. The bats were tracked using GPS tags. For analysis of the home rage, Minimum Convex Polygon (MCP) and Kernel Home Range (KHR) methods were used. The landscape types of all positional information were analyzed using ArcGIS 9.3.1 (ESRI Inc.). The average home range of 16 R. ferrumequinum individuals was 68.63 ± 25.23 ha, and the size of the overall home range for the females (85.49 ± 25.40 ha) was larger than that for the males (51.76 ± 8.30 ha). The highest average home range for the males was found in August (61.21 ± 0.01 ha), whereas that for the females was found in September (112.27 ± 5.94 ha). The size of 50% KHR ranged from a minimum of 13.26 ha to a maximum of 31.00 for the males and a minimum of 8.02 ha to a maxinum of 42.16 ha for the females, showing no significant differences between the two sexes. In addition, males and females showed no differences in the size of 50% KHR in the monthly comparisons. However, the females showed differences in the size of their core area between periods before and after giving birth. The comparisons between 100% MCP and 50% KHR showed that the types of habitats used by R. ferrumequinum were mostly forest areas, including some farmlands. In addition, comparisons with a land cover map showed that the proportion of broad-leaved forests was the highest, followed by that of mixed forests.
6.
2018.08
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The purpose of this study was to minimize salt water intrusion into freshwater aquifers and limit the development of freshwater aquifers, by selecting an appropriate excavation depth of in the western coastal area of Jeju Island. The study site was mostly basaltic lava, which was mainly composed of trachy basalt. A vertical logging test was conducted to investigate the vertical distribution of the groundwater and saline groundwater interface in the study well. It was found that freshwater groundwater, saline groundwater, and freshwater groundwater are distributed from the surface to approximately 16 m, 16∼50 m, and 50∼60 m, below the ground, respectively. In order obtain saline groundwater and minimize the inflow of freshwater into this well, the drilling depth should be limited in the range of 16∼50 m from the surface. Thus, saline groundwater well development should be carried out with reference to the measurement results, which depend on the drilling depth and EC (electrical conductivity) obtained with drilling apparatus for geology and ground handling.
7.
2018.08
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The changes on community structures of benthic macroinvertebrates, relevance to the environment and interrelationship between benthos were studied over two years in stream with large environmental disturbance, which caused by localized heavy rain during Typhoon Chaba in October 2016. As a result, the number of species and individuals were increased after localized heavy rain, especially numbers of individuals of Ephemeroptera and Plecoptera were greatly increased. On the contrary, those of Semisulcospira libertina and Semisulcospira forticosta of Mesogastropoda were greatly decreased. Dominant species was Baetis fuscatus of Ephemeroptera, numbers of species and individuals of Ephemeroptera, Plecoptera and Trichoptera(EPT group) were dramatically increased from 26 species, 110 individuals to 32 species, 365 individuals respectively. This suggests that the change of river bed and flow velocity due to heavy rain provided a suitable environment for the EPT group that preferred the rift of a stream. In the functional feeding group, only gathering collectors and filtering collectors were identified in autumn of 2017 because some functional groups preferentially adapted to the changed environment. The interspecific competition and environmental condition were the worst in autumn after heavy rain due to the increase individuals of some species. The ecological score of benthic macroinvertebrate community(ESB) was higher after the heavy rain than before. Results of the Group Pollution Index(GPI), Korean Saprobic Index(KSI) and Benthic Macroinvertebrate Index(BMI) were similar to those before and after heavy rainfall. Therefore, ESB was the most discriminating method for estimating the biological water quality in this study. Some species that are sensitive to water quality changes still appear or increase individuals in the area under investigation after the heavy rain. On the other hand, the individuals of some pollutant species decreased. This is thought to be because the habitat fluctuation caused by heavy rainfall has improved the water environment.
8.
2018.08
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Few prior studies investigated the correlation between corporate ownership structure and environmental information disclosure. Using environmental index disclosure in GRI (Global Reporting Initiative) reports of the Korean companies, the study examines the effects of ownership structure on the magnitude of environmental information disclosure. A total of 220 firm-years during 2013-2016 period are analyzed. The empirical results of the study indicate that the institutional and foreign investors’ ownership have positive correlations with environmental information disclosure, while the executives' within board of directors has a negative correlation. The ownership by largest shareholders including those with special interests shows no significant relationship with the environmental information disclosure.
9.
2018.08
서비스 종료(열람 제한)
In order to address housing issues, alleviate the concentration of urban populations, and resolve other issues regarding residential spaces, large residential complexes have been developed in Korea since the 1970s. The changes to the residential culture due to such development projects propagated rapidly, making the apartment complexes the most representative form of housing in Korea. In developing such large-scale complexes, plans for public open spaces, which play an important role in formulating the quality of residential environment, have been mostly the same, only utilizing the spaces remaining after planning other types of spaces. The current study looks at the case of Tama New Town development project, a Japanese new town development project that has a similar public open space system in large scale residential complex development projects in Korea. In doing so, the current study aims to identify the features of public open space plans. In the conclusion, the study first finds that various public open spaces must be reviewed and introduced in term of predicting social demands. Second, the study suggests the policy-makers should actively introduce pedestrian paths as a public open space. Third, the study deduces the planning implications of applying the principle of original landscape preservation.
TECHNICAL NOTE
10.
2018.08
서비스 종료(열람 제한)
In this study, to investigate an optimal configuration method for the modeling system, we performed an optimization experiment by controlling the types of compilers and libraries, and the number of CPU cores because it was important to provide reliable model data very quickly for the national air quality forecast. We were made up the optimization experiment of twelve according to compilers (PGI and Intel), MPIs (mvapich-2.0, mvapich-2.2, and mpich-3.2) and NetCDF (NetCDF-3.6.3 and NetCDF-4.1.3) and performed wall clock time measurement for the WRF and CMAQ models based on the built computing resources. In the result of the experiment according to the compiler and library type, the performance of the WRF (30 min 30 s) and CMAQ (47 min 22 s) was best when the combination of Intel complier, mavapich-2.0, and NetCDF-3.6.3 was applied. Additionally, in a result of optimization by the number of CPU cores, the WRF model was best performed with 140 cores (five calculation servers), and the CMAQ model with 120 cores ( five calculation servers). While the WRF model demonstrated obvious differences depending on the number of CPU cores rather than the types of compilers and libraries, CMAQ model demonstrated the biggest differences on the combination of compilers and libraries.
