• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.75-82
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• 2001

Microorganisms can attach firmly to food contact surface material and the resitance of adherent bacteria differ markedly from planktonic cells. Therefore, adherent cells are a potential contamination problem to the food preparation because of their high resistance. to sanitation and heat treatment. This study was carried out in order to investigate growth and decontamination of Listeria monocytogenes attached to stainless steel, glass and plastic. Listeria monocytogenes cells could attach to all types of surface at three temperatures after contact times for 24 hrs. The numbers of adherent cells were greater at higher temperatures, but not increased with incubation time. When recovery of adherent cells was investigated, after 24 grs, the numbers of adherent cells were about 10$^{7}$ , 10$^{10}$ , 11$^{11}$ at 4$^{\circ}C$, $25^{\circ}C$, 3$0^{\circ}C$ repectively. Planctonic cells decreased by 2 log cycles after exposure to the domestic sanitizer. Adherent cells showed high resistance to domestic sanitizers and that was dependent upon surface materials studied, being greatest on plastic followed by stainless steel and glass. Adherent cells were more resistant to heat treatment than planktonic cells. When adherent cells were exposed to the temperature of 5$0^{\circ}C$, 55$^{\circ}C$, 57.5$^{\circ}C$ for 10 min, their populations did not decrease significantly. When the temprature increased to 6$0^{\circ}C$, cells attached to all types of surfaces were completely inactivated for 10 min.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.292-297
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• 1999

This study was performed to estimate the possibility of use of plant materials as catalytic agents fur the decontamination of waste waters contaminated with organic pollutants by using 2,4-dichlorophenol(2,4-DCP) as a model pollutant. Plant materials containing high peroxidase activity were selected as catalysts for the removal of 2,4-DCP. Peroxidase activity, which plant materials were containing, was measured, and the greatest peroxidase activity was observed in shepherd's purse, followed by turnip, sweet potato, Chinese cabbage and white radish. The peroxidase activity in shepherd's purse was four times higher than that of horseradish purchased in U.S.A. Using shepherd' s purse and turnip, it was investigated the effect of various factors on the decontamination of 2,4-DCP through oxidative coupling. The removal of 2,4-DCP was extremely fast, and a maximal removal could be achieved within 3 min for shepherd' s purse and 15min for turnip. The pH range was from 3.0 to 8.0 and the amount of $H_2O_2$ added was 9mM when maximal removal was achieved(over 90%). No increasing removal of 2,4-DCP was observed due to increasing the amount of $H_2O_2$ added (over 9mM). The initial concentration affected the transformation of 2,4-DCP incubated with plant materials. When turnip was used as catalytic agent, it was observed decreasing transformation of 2,4-DCP due to increasing initial concentration.

• Journal of Environmental Policy
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• v.14 no.2
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• pp.27-47
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• 2015

In this paper, we present a new empirical method to estimate the environmental efficiency of decision making units. We propose a model with a new approach that describes a network process consisting of two stages, production and wastewater abatement based on the data extracted from 51 Korean industrial complexes. Taking into account the inter-dependency of two stages, we show a process how to decompose the environmental efficiency into production efficiency and abatement efficiency. Moreover, our new proposed method can be used to explain the information on network relationship between economic growth and environmental protection.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.182-190
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• 2004

An unique extraction chromatographic column (TOA: Tri-n-octylamine on Teflon powder) with a two-stage sample loading was prepared to separate Np and Pu from the environmental matrix. Np and Pu were efficiently retained in 4 M $HNO_3$ medium on the column and easily eluted with 0.02 M oxalic acid in 0.16 M HNO$_3$at $95^{\circ}C$. The separated solutions were free from most of the matrix elements and were aspirated into the ICP-MS directly. The decontamination factor for 238U is more than 104. The instrumental detection limit for 237Np was 0.46 pg mL-l ($1.2{\times}10_{-5}$Bq mL-l), and for 239Pu was 0.48 pg mL-l ($1.1{\times}10_{-3}$ Bq mL-l). The feasibility for the determination of both elements was proved by analysing IAEA-135 reference samples, the measured values agreed with the recommended reference value.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1207-1215
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• 2008

To investigate the occurrence and species diversity of mycobacteria in waters, surface water samples were collected monthly from the Han River and tap water samples at the terminal sites of the distribution system. Mycobacteria in each water sample were isolated by decontamination using cetylpyridinium chloride (CPC) and cultivation on Middlebrook 7H10 agar, and then identified by polymerase chain reaction-restriction fragment length polymorphism analysis (PRA) and sequencing of the 65-kDa heat-shock protein gene (hsp65 gene). Mycobacteria were detected in 59% of the surface water samples and 26% of the tap water samples. Over half of the 158 isolates could not be identified by hsp65 PRA and gene sequencing, and several identification discrepancies were observed between the two methods. The most frequently isolated species was Mycobacterium gordonae in surface water and M. lentiflavum in tap water. M. avium complex (MAC), the most important pathogen among environmental mycobacteria, was detected in the surface water samples but not found in the tap water samples. The result demonstrated that water is an important environmental source of mycobacteria and the combined application of hsp65 PRA and sequencing was more reliable than hsp65 PRA alone to accurately identify mycobacteria present in water.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.73-86
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• 1999

The ion-exchange method for the purification of primary coolant has been used broadly in PWR(pressurized water reactor)-type nuclear power plants due to its high decontamination efficiency, simple system, and easy operation. However, its non-selective removal of metal and non-radionuclides shortens its life, resulting in the generation of a large amount of waste ion-exchange resin. In this study, the feasibility of electrodeionization (EDI) was investigated for the purification of primary cooling water using synthetic solutions under various experimental conditions as an alternative method for the ion exchange. The results shows that as the feed flow-rate increased, the removal efficiency increased and the power consumption decreased. The removal rate was observed as a 1000 decontamination factor(DF) at a nearly constant level. For the synthetic solution of 3 ppm TDS (Total Dissolved Solid), the power consumption was 40.3 mWh/L at 2.0 L/min of feed flow rate. The higher removal rate of metal species and lower power consumption were obtained with greater resin volume per diluting compartment. However, the flow rate of the EDI process decreased with the elapsed time because of the hydrodynamic resistivity of resin itself and resin fouling by suspended solids. Thus, the ion-exchange resin was replaced by an ion-conducting spacer in order to overcome the drawback. The system equipped with the ion-conducting spacer resolved the problem of the decreasing flow rate but showed a lower efficiency in terms of the power consumption, the removal rate of metal species and current efficiency. In the repeated batch operation, it was found that the removal efficiency of metal species was stably maintained at DF 1000.

• The Korean Journal of Food & Health Convergence
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• v.6 no.1
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• pp.17-20
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• 2020

Wheat is the most abundant crop in the world, accounting for one third of the world's population diet. In Ukraine, wheat is in fact, in addition to its nutritional value, a national symbol of the state. Therefore, the main thesis on the development of modern plant growing in Ukraine is the reduction of costs and the introduction of innovative technologies. The quality of grain and seed depends on many factors, namely: agro-climatic conditions, sowing condition of the seed material, quality characteristics of the soil, yielding properties of seeds, pre-sowing seed treatment. etc. For this purpose, the photosynthesis and intensity of photosynthesis need to be limited to the width of the leaf and the height of the leaves by a smaller cut of the stem. It is extremely important to ensure that the head and side pagons of wheat are in good condition. All parameters are often secured by the technology of grain preparation before delivery. Prior to this technology, it is possible to introduce processing of the material in the form for the development of the material. This article presents the effectiveness of the use of infrared irradiation for the pre-sowing treatment of winter wheat seeds in Sekobra Research, Germany.

• Membrane Journal
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• v.16 no.1
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• pp.77-84
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• 2006

Transport mechanisms of nickel ion through a continuous electrodeionization (CEDI) were investigated in terms of electric properties of ion exchange textile (IET). The porous plug model and extended Nernst-Plank (N-P) equation were applied for the description of transport mechanism of nickel ion. The model revealed that the CEDI performance was mainly due to the induced current not accelerated mobility by IET. This study also suggested that optimal operating conditions are attained with minimized electroregeneration region.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.18-27
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• 1998

Biopulping is defined as the treatment of wood chips with lignin-degrading fungi prior to pulping. Fungal pretreatment prior to mechanical pulping reduces electrical energy requirements during refining or increases mill throughput, improves paper strength, reduces the pitch content, and reduces the environmental impact of pulping. Our recent work involved scaling up the biopulping process towards the industrial level, investigating both the engineering and economic feasibility. We envision the process to be done in either a chip-pile or silo-based system for which several factors need to be considered: the degree of decontamination, a hospitable environment for the fungus, and the overall process economics. Currently, treatment of the chips with low-pressure steam is sufficient for decontamination and a simple, forced ventilation system maintains the proper temperature, humidity, and moisture conditions, thus promoting uniform growth of the fungus. The pilot-scale trial resulted in the successful treatment of 4 tons of wood chips (dry weight basis) with results comparable to those on a laboratory. Larger, 40-ton trials were also successful, with energy savings and paper properties comparable with the laboratory scale. The overall economics of the process also look very favorable and can result in significant annual savings to the mill. Although the current research has focused on biopulping for mechanical pulping, it is also beneficial for sulfite chemical pulping and some applications to recycled fiber have been investigated.

• Journal of Radiation Protection and Research
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• v.47 no.1
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• pp.30-38
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• 2022

Background: Residential areas have some factors on the external exposure of residents, who usually spend a long time in these areas. Although various survey has been carried out by the government or the research institutions after the Fukushima Daiichi Nuclear Power Plant accident, the mechanism of radiocesium inventory in the terrestrial zone has not been cleared. To better evaluate the radiation environment, this study investigated the temporal changes in air dose rate and ¹³⁷Cs inventories (Bq/m²) in residential areas and agricultural fields. Materials and Methods: Air dose rate and ¹³⁷Cs inventories were investigated in residential areas located in an evacuation zone at 5-8 km from the Fukushima Daiichi Nuclear Power Plant. From December 2014 to September 2018, the air dose rate distribution was investigated through a walking survey (backpack survey), which was conducted by operators carrying a γ-ray detector on their backs. Additionally, from December 2014 to January 2021, the ¹³⁷Cs inventories on paved and permeable grounds were also measured using a portable γ-ray detector. Results and Discussion: In the areas where decontamination was not performed, the air dose rate decreased faster in residential areas than in agricultural fields. Moreover, the ¹³⁷Cs inventory on paved surfaces decreased with time owing to the horizontal wash-off, while the ¹³⁷Cs inventory on permeable surfaces decreased dramatically owing to the decontamination activities. Conclusion: These findings suggest that the horizontal wash-off of ¹³⁷Cs on paved surfaces facilitated the air dose rate decrease in residential areas to a greater extent compared with agricultural fields, in which the air dose rate decreased because of the vertical migration of ¹³⁷Cs. Results of this study can explain the faster environmental restoration in a residential environment reported by previous studies.