• Nuclear Engineering and Technology
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• v.39 no.6
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• pp.747-752
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• 2007

The Proton Engineering Frontier Project (PEFP) has designed and developed a proton linear accelerator facility operating at 100 MeV - 20 mA. The radiological effects of such a nuclear facility on the environment are important in terms of radiation safety. This study estimated the production rates of radionuclides in the soil around the accelerator facility using MCNPX. The groundwater migration of the radioisotopes was also calculated using the Concentration Model. Several spallation reactions have occurred due to leaked neutrons, leading to the release of various radionuclides into the soil. The total activity of the induced radionuclides is approximately $2.98{\times}10^{-4}Bq/cm^3$ at the point of saturation. $^{45}Ca$ had the highest production rate with a specific activity of $1.78{\times}10^{-4}Bq/cm^3$ over the course of one year. $^3H$ and $^{22}Na$ are usually considered the most important radioisotopes at nuclear facilities. However, only a small amount of tritium was produced around this facility, as the energy of most neutrons is below the threshold of the predominant reactions for producing tritium: $^{16}O(n,\;X)^3H$ and $^{28}Si(n,X)^3H$ (approximately 20 MeV). The dose level of drinking water from $^{22}Na$ was $1.48{\times}10^{-5}$ pCi/ml/yr, which was less than the annual intake limit in the regulations.

• Journal of Environmental Science International
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• v.33 no.6
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• pp.417-425
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• 2024

This study investigated the effects of various planting models on the joint cultivation of eggplant (Solanum melongena) and marigold (Tagetes erecta)to enhance sustainable rooftop urban farming. Rooftop agriculture is increasingly valued to boost the food supply and benefit the environment. Integrating such practices into urban planning is viewed as a way to sustainably manage resources and improve the food-energy-water cycle in cities. The experiment was conducted on a rooftop in Chungju, South Korea from May to August. Four different planting setups were used: central eggplant with peripheral marigold (SET), eggplant with a protective net (SIC), central marigold with peripheral eggplant (TES), and control with only eggplant (CON S). These models tested the effects of companion planting versus monoculture using a lightweight soil mix ideal for rooftops made from cocopeat and perlite and enriched with organic fertilizer. Measurements focused on soil conditions and plant health and assessed soil temperature, moisture, conductivity, plant height, width, and leaf size. The results indicated that the SET modelyielded the best growth. This setup benefited from marigold pest control properties and its ability to improve soil conditions by enhancing moisture and nutrient levels and aiding eggplant growth. These findings underscore the potential of mixed planting on rooftops and suggest that such approaches can be effectively incorporated into urban agriculture to boost yield and environmental sustainability. This study supports the idea that diverse planting methods can significantly affect plant growth and promote urban greening and food security.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.56-61
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• 1997

A strain producing immunosuppressive substances was isolated from a soil in Cheju island. By morphological, cultural, and physiological studies, the strain was identified as Streptomyces lydicus MCY-524. Cultured broth was purified by silica gel, sephadex LH-20 and preparative HPLC and gave two immunosuppressive compounds, MCH-22 and MCH-32. They dramatically suppressed the B cell activation with lipopolysaccharide, T cell activation by mixed lymphocyte response, and primary T-dependent antibody response at a final concentration of 1 ${\mu}g$/ml. They also markedly suppressed the proliferation of lymphocytes induced by lipopolysaccharide, pokeweed mitogen, and concanavaline A at the same concentration. Their suppressive activities, which were comparable to those of cyclosporin A, suggested that they were potent and broad immunotoxic agents on the immune functions of murine lymphocytes.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.89-99
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• 1998

Sorption of the aqueous cyanide onto steel mill sludge and steel mill slag, both of which are the by-products from the converter furnace, was studied. In the study, the influence of temperature, activation energy, concentration and pH on sorption of cyanide was investigated. Three different temperature($25^{\circ}C$ > $37^{\circ}C$> $50^{\circ}C$) was chosen to represent that of landfill leachate. Initial concentration was 1 mg/$\ell$ 5 mg/$\ell$, 10 mg/$\ell$, and 20 mg/$\ell$. In addition, pH was set to three different level, that is, 3, 7, and 11 respectively. As the result of batch mode experiment for cyanide adsorption, the removal rate was found to be proportional to the initial concentration of cyanide. The order of removal rate was 20 mg/$\ell$> 10 mg/$\ell$> 5 mg/$\ell$> 1 mg/$\ell$. Similarly the influence of pH was proportional because of the change in solubility of cyanide. The order of removal rate was pH 11 > pH 7 > pH 3. As the temperature increased, so did the removal rate. The reaction was endothermic and the value of activation energy(Ea) was 127.93 J/mole and 59.44 J/mole respectively at 1 mg/ιand 20 mg/ιof initial concentration. From the experiment, it can be postulated that the capability of steel mill by-products to attenuate aqueous cyanide is enough to be used as substitute for clay liner of landfill site in the aspect of pollutant removal.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.69-77
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• 2020

Oxidative degradation of phenol, three monochlorophenols (2-chlorophenol, 2-CP; 3-chlorophenol, 3-CP; 4-chlorophenol, 4-CP), four dichlorophenols (2,3-dichlorophenol, 2,3-DCP; 2,4-dichlorophenol, 2,4-DCP; 2,5-dichlorophenol, 2,5-DCP; 2,6-dichlorophenol, 2,6-DCP), and two trichlorophenols (2,4,5-trichlorophenol, 2,4,5-TCP; 2,4,6-trichlorophenol, 2,4,6-TCP) was conducted with heat activated persulfate. As the number of chlorinations increased, the reaction rate also increased. The reaction rate was relatively well fitted to the zero-order kinetic model, rather than the pseudo-first order kinetic model for the reactions at 60 ℃, which can be explained by insufficient activation of the persulfate at 60 ℃, and the oxidation reaction of 2,4,6-TCP at 70 ℃ was relatively well fitted to the pseudo-first order kinetic model. The oxidation reaction rate generally increased with increase of persulfate concentration in the solution. 2,6-dichloro-2,5-cyclohexadiene-1,4-dione was found as a degradation product in a GC/MS analysis. This compound is a non-aromatic compound, and one chlorine was removed. This result is similar to the result of previous studies. The current study proved that heat activated persulfate activation could be an alternative remediation technology for phenol and chlorophenols in soil and groundwater.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.5
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• pp.453-467
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• 2000

The aim of this research is to collect and characterize fine particles (FPM:$\leq$2.5${\mu}{\textrm}{m}$) and coarse particles (CPM: 2.5~10${\mu}{\textrm}{m}$) using a low volume air sampler provided by the IAEA, at urban (Taejon) and rural area(Wonju) for a period of about two years(April 1996 to May 1998) and to promote a use of nuclear analytical techniques for air pollution studies. For the collection of airborne particulate matter (PM(sub)10), the Gent stacked filter unit sampler and polycarbonate membrane filters were employed. The concentration of trace elements in collected APM samples were determined byu instrumental Neutron Activation Analysis. For validation of the analytical data, internal quality control were implemented by using both the comparison of the analytical results of standard reference materials(NIST SRM 1648) and interlaboratory comparison for proficiency test (NAT-3). The standard uncertainty was less than 15% and Z-score of two samples were within $\pm$1. The monitoring of (PM(sub)10) mass concentration and elemental concentrations were carried out weekly. The average mass concentration of (PM(sub)10) in urban and rural areas were 59.2$\pm$36.5$\mu\textrm{g}$/㎥ and 41.4$\pm$23.7$\mu\textrm{g}$/㎥, respectively. To investigate the emission source, the enrichment factors were calculated for the fine and coarse particle fractions at two sites, respectively and these values were classified for anthropogenic and soil origin elements.

• KCI Concrete Journal
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• v.13 no.1
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• pp.3-9
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• 2001

This research concerns the effect of kaolin as material of cement admixture. which has the advantage of low price and high adaptability. Kaolin, a kind of soil, is well known as a raw material of pottery. which is widely scat-tered on the earth (especially in Korea). This research shows the method and process for activating kaolin to have the properties of a cement admixture through experiment. In the experiments, kaolin is baked in high temperature and then cooled suddenly to be activated. The temperature zone and time span, on which kaolin is activated are examined. The research looks over the effect of the activated kaolin based on several criteria regarding to chemical and physical characteristic of general admixtures. The results of this research are as follows; kaolin start activation at the temperature above 50$0^{\circ}C$ and make ends of activation at the temperature below 95$0^{\circ}C$ and there was little effect by the change of duration. It is concluded that compressive strength can be increased by putting activated kaolin in the concrete and the activated kaolin is good for water resistance and anti-chemical , and that it is effective for protecting the leakage of hazardous article like Cl- and for protecting damage by an organic salt like acid. The activated kaolin of proper temperature and time is effective in compressive strength, salt resistance and acid resistance. The adaptability of activated kaolin as a cement admixture was shown through this research.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.575-585
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• 2007

Microbial control of the geochemical behavior of heavy metals (Cd, Cu, Pb, and Zn) and As in contaminated subsurface soil and sediment was investigated through activation of indigenous bacteria with lactate under anaerobic condition for 25 days. The results indicated that dissolved Cd, Pb and Zn were microbially removed from solutions, which was likely due to the formation of metal sulfides after reduction of sulfate by indigenous sulfate-reducing bacteria. Soils from the Dukeum mine containing a large amount of sulfate resulted in complete removal of dissolved As after 25 days by microbial activities, while there were gradual increases in dissolved As concentration in soils from the Hwabuk mine and sediments from the Dongducheon industrial area which showed low $SO_4{^2-}$ concentrations. Addition of appropriate carbon sources and sulfate to contaminated geological media may lead to activation of indigenous bacteria and thus in situ stabilization of the heavy metals; however, potential of As release into solution after the amendment should be preferentially investigated.

• Spatial Information Research
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• v.11 no.3
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• pp.241-249
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• 2003

The purpose of this paper is to provide the basic data to select the most proper site, which is essential for the economic activation of North Korea by means of the GIS tool. In this purpose, firstly, Nampo area is sampled as model case, classifying the factors into the natural environmental one and socio- cultural one. Secondly, to analyze the land use status and topographic status which is essential for natural environment factor. Besides USLE(Universal Soil Loss Equation), which is one of the disaster effect assessments, is being applied to suggest the selection method for minimizing the environment change by way of assuming the land effluence amount. The started could advance to prove the ideal model in selecting the most suitable site while minimizing the environmental change by means of the composite tool of GIS and USLE.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.5
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• pp.363-372
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• 2002

PM$_{10}$ aerosols were collected using low volume air sampler every month intervals from September 1992 to August 1991 in Seoul. These samples were analyzed for 20 trace elements (Al, As, Ba, Br, Ca, Cl, Co, Cr, Fe, K, Mn, Na, Ni, Pb, Sc, Se, Si, Ti, V and Zn) by INAA (instrumental neutron activation analysis), XRF (x-ray fuorescence spectrometer), and ICP (inductively coupled plasma). PM$_{10}$ mass concentrations higher than 70 $\mu$g/m$^3$ were 32% of 60 samples and had significantly higher concentrations in spring and winter than in summer and fall (p-value<0.001). The elements of As, Br, Cl, Ni, Pb, Se, V, and Zn are enriched by factors of 20 to 2,000 relative to their natural abundance in crustal soil. To further identify common sources of pollution-related trace elements, factor analysis was applied to the trace elements concentration data. Major sources that contribute to the atmospheric loading of these elements were found to include fossil fuel combustion, automobile and waste incineration (33.2%), metal processing industry (18.2%), and soil(29.8%).8%).