• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.50-66
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• 1998

This study was conducted to estimate crystalline silica contents in airborne respirable dust from various manufacturing industries and to compare analytical performance of two methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy (FTIR). For this study, various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: foundry, brick, potteries, concrete, and abrasive material, etc. Both personal and area respirable dust samples were collected using 10 mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size, polyvinylchloride (PVC) filters as collection media. In addition, total dust samples were collected side-by-side to the respirable samples. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 0500, 7500, and 7602 for dust collection and quartz analysis. In addition, bulk samples were collected and analyzed by X-ray fluorescence (XRF) for minerals. In this article, only the results obtained from foundry are reported. The results from various other industries will be published in future articles. The respirable dust concentrations from personal samples by cyclone were $0.46-1.06mg/m^3$ and those from area samples were $0.34-0.73mg/m^3$. Dust concentrations of personal samples were significantly higher than those of area samples. The highest dust concentration was obtained from the personal samples of the finishing operation. Total dust concentration ranged $1.24-3.40mg/m^3$. The mean quartz contents estimated by FTIR and XRD in the personal respirable dust samples were 5.12% and 4.41%, respectively, without significant difference between them. For quartz analyses, the two techniques were highly correlated with $r^2$ ranged 0.803-0.920. But the results by FTIR were mostly higher than those by XRD. In addition, cristobalite was not detected by FTIR. Significant correlations between contents of crystalline silica and such minerals as $Al_2O_3$, CaO, $TiO_2$, and $K_2O$ suggest possible interferences from these minerals.

• Journal of Science and Technology Studies
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• v.18 no.1
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• pp.129-175
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• 2018

This paper examines asbestos activism in South Korea by focusing on the politics of knowledge between the asbestos activist group and regulatory agency on the risk of asbestos exposure. Asbestos activism has contributed to establishing asbestos pollution an important safety and public health agenda in South Korea. Asbestos pollution investigation is key to core argument of the activism that asbestos pollution is pervasive especially in urban environment and a serious environmental health problem with its worst consequences has not yet seen. A distinctive characteristic of such asbestos investigation is the use of "settled dust analysis," non-standard, non-legislated analysis method. In this paper, literary technologies used in asbestos investigation report written by activists and controversies over asbestos pollution measurement in Samsung's head office building. Asbestos activists successfully concentrated media's attention on their argument and mobilize resources needed to make policy decisions, by using settled dust analysis data. Regulatory agency and expert group, however, neither saw settled dust analysis nor activists argument persuasive enough to make policy changes, base on their evaluation on the use of standards and evidentiary context for analyzing measured data. While its explanatory power is partially acquired, through the dispute between asbestos activists and regulatory agencies unspoken assumptions of regulatory science was revealed and became the matter of social debate. Settled dust analysis captures the characteristic of asbestos analysis which combined social movement and science to challenge the regulatory agency and expert group.

• The Korean Journal of Mycology
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• v.8 no.1
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• pp.33-43
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• 1980

Thirteen strains or crosses of Lentinus edodes obtained from home and abroad were compared for their mycelial characteristics on artificial media. Eleven of them were selected and inoculated on logs in order to study for their productivity, and the morphological characteristics of the mushrooms were investigated. 1) Seven strains, i. e., 11001, 12001, 13005, 13012, 13015, 12004 and 20101 were grown well on the sawdust medium. 2) The best mycelial growth and establish­ment of infection on logs were obtained from strains 20101 and 11001. 3) The highest yield of the mushrooms on logs during the six year periods were obtained from strains 11001, 12001 and 20101. 4) The highest yield of the mushrooms usually was obtained on the fourth year after inoculation. 5) The fruit body productivity in terms of dry weight recovery was the highest in strains 13005 and 20101. 6) The most productive period of the mushrooms during the years depended on strains. Most prevalent types of the strains were summer and autumn growing types, and more mushrooms were produced during these periods. 7) Morphological characteristics of the mushroom were more or less dependent on environmental conditions. 8) Thicker fruit bodies and relatively uniform shapes of the mushroom were produced by strain 20101.

• The Korean Journal of Mycology
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• v.41 no.2
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• pp.85-90
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• 2013

This study investigated the internal and external morphological characteristics of decomposition and browning of oak sawdust medium for ground bed cultivation of Lentinula edodes. Within fifty days after L. edodes inoculation, surface hyphae on the bed browned. In 110 days, the fungal hyphae occupied and decomposed wood fibers, vessels and parenchymatous cells from the inside as white profuse hyphal mass was amorphously dissolving the saw dust particles from the outer surface. Most of the white hyphal bed surface became cleanly brown, however, some colony surface became blackened and slimy with contaminating bacteria, hyphae and spores. The brown layer was ca. 0.34 mm thick with highly dense and white hyphal mass beneath, whereas the blackened layer was ca. 1.17 mm thick with shrunken hyphae and less decomposed sawdust particles beneath. The surface hardness of the brown surface was ca. $0.73kgf/cm^2$, soft and resilient, while that of the blackened was ca. $0.91kgf/cm^2$, hard and nonresilient. By 150 days Lentinula edodes mushrooms fruited only on the brown surface and not on the blackened medium.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.247-253
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• 2002

The cellular responses of TNT-degrading bacterium, Stenotrophomonas sp. OK-5 to explosive 2,4,6-trini-trotoluene (TNT) as an environmental contaminant were examined. Survival of the strain OK-5 with time in the presence of different concentrations of TNT under sublethal conditions was monitored, and viable counts paralleled the production of the stress shock proteins in this bacterium. Total cellular fatty acids analysis showed that strain OK-5 produced or disappeared several different kinds of lipids when grown on TNT media than when grown on TSA. Under scanning electron microscope, the cells treated with 0.5 mM TNT for 12 hrs showed irregular rod shapes with wrinkled surfaces. Analyses of SDS-PAGE and Western blot using anti-DnaK and anti-GroEL revealed that several stress shock proteins including 70 kDa DnaK and 60 kDa GroEL in strain OK-5 were newly synthesized at different TNT concentrations in exponentially growing cultures. 2-D PAGE of soluble protein fractions from the culture of OK-5 exposed to TNT demonstrated that approximately 300 spots were observed on the silver stained gel ranging from pH 3 to pH 10. Among them, 10 spots significantly induced and expressed in response to TNT were selected and analyzed. As the result of internal amino acid sequencing with ESI-Q TOF, two proteins, spot #1 and spot #10 were assigned the DnaK protein XF2340 of Xylella fastidiosa and stress-induced protein of Mesorhizobium loti, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.991-996
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• 2003

Determination of regional microbial contamination in the process of rice rolled in dried laver (Kimbab) and effects of gamma irradiation on the improvement of hygienic quality and shelf stability were investigated. Total aerobic bacterial distribution of raw materials of Kimbab were; 10$^{6}$ ∼10$^{7}$ CFU/g in dried laver, 10$^3$ CFU/g in cucumber and below 10 CFU/g in steamed rice, ham, fried egg, and salted radish. Total coliform bacteria were 10$^3$ CFU/g in dried laver and detected below detection limit (10 CFU/g) in other raw materials. And it was arithmetically calculated that the levels of total aerobic bacteria and coliform bacteria in Kimbab does not exceed 10$^{5}$ CFU/g and 10$^1$ CFU/g under the aseptic process, respectively. However, microbial contamination levels in just prepared Kimbab in a market were about 10$^{6}$ CFU/g of total aerobic and coliform bacteria. Therefore, it was considered that microbial contamination of Kimbab is mainly originated from environmental uptake during the preparation. The representative media for putrefying bacterial growth were steamed rice. Coliform bacteria were mainly increased in ham and fried egg during storage. The bacteria in dried laver were radio-resistant and survived at 3 kGy of gamma irradiation. Coliform bacteria on EMB agar plate were eliminated at the dose of 2 kGy. The sensory acceptability of 2 kGy irradiated Kimbab was stable and the Kimbab can be preserved for 24 hour at 15$^{\circ}C$. Therefore, it was considered that optimal irradiation dose for radicidation of Kimbab was 2 kGy.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.1-11
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• 2004

Foam reduces the mobility of gas phase in porous media to overcome gravity override and to divert acid into desired layers in the petroleum industry and to enhance the efficiency of environmental remediation. Recent experimental studies on foam show that foam exhibits a remarkably different flow rheology depending on the flow regime. This study, for the first time, focuses on the issues of foam diversion process under the conditions relevant to groundwater remediation, combining results from laboratory linear-flow experiments and a simple numerical model with permeability contrasts. Linear flow tests performed at two different permeabilities (k = 9.1 and 30.4 darcy) confirmed that two flow regimes of steady-state strong foams were also observed within the permeability range of shallow geological formations. Foam exhibited a shear-thinning behavior in a low-quality regime and near Newtonian rheology in a high-quality regime. Data taken from linear flow tests were incorporated into a simple numerical model to evaluate the efficiency of foam diversion process in the presence of permeability contrasts. The simple model illustrated that foam in the high-quality regime exhibited a successful diversion but foam in the low-quality regime resulted in anti-diversion, implying that only foam in the high-quality regime would be applicable to the diversion process. Sensitivity study proved that the success of diversion process using foam in the high-quality regime was primarily controlled by the limiting capillary pressures (${P_c}{^*}$) of the two layers of interest. Limitations and implications are also discussed and included.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.99-111
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• 1999

The purpose of this study was to evaluate crystalline silica contents in airborne respirable dusts from various manufacturing industries and to compare analytical ability of two different methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy(FTIR). Various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: ceramics, brick, concrete, and abrasive material etc. The personal respirable dust samples were collected using l0mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size. polyvinylchloride (PVC) filters as collection media. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 7500, and 7602 for dust collection and quartz analysis. A total of 48 samples were collected from these industries. Initial analyses of these samples showed log-normal distributions for dust and quartz concentrations. Some results from ceramics and stone exceeded current Korean Occupational Exposure Limits. The average concentrations of personal respirable dust by cyclone were 0.43, 0.24, 0.26, 0.42, 0.53 and $0.29mg/m^3$ in ceramics, stone, concrete, glass, briquets, and others, respectively. A comparison of performance of two analytical methods for quantifying crystalline silica was performed using data from ceramics. The results showed that no significant difference was found between two methods for ceramics. The mean crystalline silica contents determined by XRD were 3.41 % of samples from briquets and 7.18 % from ceramics and were 2.58 % from concrete and 10.33 % from ceramics by FTIR. For crystalline silica analysis, two analytical techniques were highly correlated with $r^2=0.81$ from ceramics. Both cristobalite and tridymite were not detected by XRD and FTIR.

• Journal of Technology Innovation
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• v.20 no.2
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• pp.29-48
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• 2012

As the complexity and uncertainty of social and economic systems increase, the strategic foresight that actively and effectively responds to the environmental changes becomes important. A wide range of future forecasting methods are available for strategic foresight. Selecting one of the methods depends on several factors such as availability of time and financial resources and the objectives of the exercise. Although trend extrapolation analysis has been used for many years, scenario planning is being widely used by government and corporate as a tool for strategic decision making in recent years. Generally, scenario planning is carried out through workshop, in which experts with diverse backgrounds exchange information, views, and insights and integrate the diverse viewpoints. However, only a small number of experts can participate in a workshop and citizen opinion is not easily transformed into the policy for the scenario exercise due to the limitation of budget and short duration of a project. It is also much harder to develop creative ideas in the workshop because of the limited time and space. In this study, a new scenario process combining scenario workshop and wiki is proposed to overcome the limitation of scenario workshop. This combined approach can be more productive than using scenario workshop alone when developing new ideas. In this study, we applied the combined approach to develop scenarios for the strategic foresight of future media and present suggestions for improving the process.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.231-242
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• 2011

Recently, the green spaces in the urban areas were greatly reduced due to urbanization and industrialization. As urban structures such as roads and buildings are built, the amount of impervious area within a watershed increases. High impervious surfaces are the common causes of high runoff volumes as the soil infiltration capacity decreases and the volume and rate of runoff increase thereby decreasing the groundwater recharge. These effects are causing many environmental problems, such as floods and droughts, climate change, heat island phenomenon, drying streams, etc. Most cities attempted to reduce sewer overflows by separating combined sewers, expanding treatment capacity or storage within the sewer system, or by replacing broken or decaying pipes. However, these practices can be enormously expensive than combined sewer overflows. Therefore, in order to improve these practices, alternative methods should be undertaken. A new approach termed as "Low Impact Development (LID)" technology is currently applied in developed countries around the world. The purpose of this study was to effectively manage runoff by adopting the LID techniques. Small Constructed Wetland(Horizontal Subsurface Flow, HSSF) Pilot-scale reactors were made in which monitoring and experiments were performed to investigate the efficiency of the system in removing pollutants from runoff. Based on the results of the Pilot-plant experiments, TSS, $COD_{Cr}$, TN, TP, Total Pb removal efficiency were 95, 82, 35, 91 and 57%, respectively. Most of the pollutants were reduced after passing the settling tank and the vertical filter media. The results of this study can contribute to the conservation of aquatic ecosystems and restoration of natural water cycle in the urban areas.