• Analytical Science and Technology
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• v.13 no.2
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• pp.179-188
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• 2000

Trace elements in air samples artificially loaded on filters with urban dust and the bulk material of urban dust as an environmental sample were determined non-destructively using instrumental neutron activation analysis. Standard reference material (Urban Dust, SRM 1648) of the National Institute of Standard and Technology was used for the analytical quality control. The relative error for 37 elements was less than 15% and the standard deviation was less than 10%. 29 elements in the urban dust and 21 elements in the loaded filter sample were determined respectively. To evaluate the proficiency and reliability of the measurement, data intercomparison was performed and 39 analytical laboratories participated in the analysis using different analytical methods; neutron activation analysis, particle induced X-ray emission analysis, X-ray fluorescence analysis and atomic absorption spectrometry. Z-scores were calculated using the standard deviation of the laboratorie's mean as target standard deviation, and a good result was obtained that the values fall between -1 and +1 except some elements.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.57.1-57.1
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• 2011

It has been suggested that merging plays an important role in the formation and the evolution of early-type galaxies (ETGs). Optical-NIR color gradients of ETGs in high density environments are found to be less steep than those of ETGs in low density environments, hinting frequent merger activities in ETGs in high density environments. In order to examine if the flat color gradients are the result of dry mergers, we studied the relations between merging features, color gradient, and environments of 281 low redshift ETGs selected from Sloan Digital Sky Survey (SDSS) Stripe82. The sample contains 222 relaxed ETGs, 38 ETGs with tidal features, 10 galaxies with dust features and 11 galaxies with tidal and dust features, and Near Infrared (NIR) images are taken from UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). We find that r-K color gradients of field sample galaxies are steeper than those of sample ETGs within cluster environments. For the field sample galaxies, a relatively large number of galaxies with peculiar features contribute to the steeper color gradients, while the absence of these peculiar early-type galaxies make color gradients of the cluster sample galaxies intact. In high density environment, ETGs are already evolved and relaxed, resulting flat color gradients. However, in low density environments, a majority of ETGs undergone merging recently which makes the color gradients steep.

• Journal of The Korean Astronomical Society
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• v.47 no.4
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• pp.123-135
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• 2014

A silicate carbon star is a carbon star which shows circumstellar silicate dust features. We collect a sample of 44 silicate carbon stars from the literature and investigate the validity of the classification. For some objects, it is uncertain whether the central star is a carbon star. We confirm that 29 objects are verified silicate carbon stars. We classify the confirmed objects into three subclasses based on the evolution phase of the central star. To investigate the effect of the chemical transition phase from O to C, we use the radiative transfer models for the detached silicate dust shells. The spectral energy distributions and the infrared two-color diagrams of the silicate carbon stars are compared with the theoretical model results. For the chemical transition model without considering the effect of a disk, we find that the life time of the silicate feature is about 50 to 400 years depending on the initial dust optical depth.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3695-3702
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• 2022

South Korea, a country that built a world-class nuclear power infrastructure, shifted to a nuclear phaseout during the previous government's reign. This shift was pursued as part of a larger task of electricity mix reform, and one of the integral motives for such reform is addressing greenhouse gas (GHG) and fine dust problems. Thus, verifying the relationships between the public's concerns about GHG/fine dust and their acceptance of nuclear power generation is essential for designing public communication strategies to revive nuclear power under the ongoing environmental regime. Our analysis using a nationwide survey sample of South Korea (N = 1009, through proportionated quota sampling method) showed that the more people are concerned about GHG and fine dust, the less they accept nuclear power. These relationships held even after controlling for the effect of a third variable-energy-related environmentalism. This finding means that despite past communication efforts positioning nuclear power as a generation source that can mitigate GHG/fine dust emissions and the widely accepted scientific evidence that supports such positioning, nuclear power in Korea is in jeopardy. Our finding provides implications for public communications and fundamental knowledge for research on the determinants of nuclear power acceptance.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.168-179
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• 1994

In some ceramic industries, worker exposure to dust, crystalline free silica and lead were determined and evaluated. The conclusions are as follows. 1. Crystalline silica in bulk samples was 10.5 % in sanitary ware industry, 9.4 % in tile industry, and 2.1 % in ceramic insulator industry respectively. The free silica content of air filter sample was 8.03 % in table ware industry, 5.59 % in sanitary ware industry, and 1.32 % in ceramic insulator industry. Because silica content in ceramic dust is relatively high, it is should be considered silica as important factor in evaluating for ceramic industry. 2. The silica contents in dust from tile, sanitary ware and table ware industries are above 5%, it should be classified as "Type" 2 dust. 3. The airborne concentration of respirable crystalline silica was $27.9{\mu}g/m^3$ in a sanitary ware factory and $5.8{\mu}g/m^3$ in a ceramic insualtor factory. Three of ten samples sampled the above factories were exceeded the occupational exposure levels, $100{\mu}g/m^3$. 4. Geometric mean(GM) of total dust in 11 factories was $1.00mg/m^3$ and GM of respirable dust concentration in 5 factories was $0.33mg/m^3$. Sanitary ware industry had the highest concentration of total dust, $1.62mg/m^3$ and of respirable dust, $0.88mg/m^3$. 5. Average lead concentration in air was $0.05mg/m^3$ in glazing process of 2 factories manufacturing table ware. Five of ten sample(50%) were exceeded $0.05mg/m^3$. Therefore lead exposure in pottery industry should be considered as important problem.

• Journal of Soil and Groundwater Environment
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• v.23 no.6
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• pp.82-89
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• 2018

The objective of this study is to evaluate efficiencies of chemical suppressants for control of fugitive dust in ash pond of thermal power plant. In this study, $MgCl_2$, PAM (polyacrylamide), and PVA (poly vinyl alcohol) that are generally applied to suppression of fugitive dust generated from unpaved road, coal mining, storage piles and etc, were employed as chemical dust suppressants. The coal ash (coal combustion residuals) were sampled from the ash pond of Yeongheung power division in Incheon, South Korea. The characterization of the sample including particle size distribution, pH, $pH_{PZC}$ and pore volume as well as XRF analysis were carried out. The suppressant treated-samples were investigated with the wind tunnel experiments to estimate and compare the effect of suppressants on stabilization of the surface of coal ash samples. According to the results, the stability of suppressant-treated samples were significantly improved compared to water-treated samples. Among the three kinds of suppressants, PAM and PVA showed higher efficiencies and cost saving than $MgCl_2$.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.477-478
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• 2010

• The Bulletin of The Korean Astronomical Society
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• v.28 no.2
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• pp.41-41
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• 2003

• Korean journal of applied entomology
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• v.9 no.1
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• pp.1-6
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• 1970

Cadmium pentachlorophenolxanthate has been synthesized with pentachlorophenol, carbondisulfide sodium hydroxide and cadmium chloride and its fungicidal activity was tested to Pyricularia oryzae and Cochliobolus miyabeanus. The results are summarized as followes; 1) The sample V synthesized by acidifying the crude PCP-xanthate solution at pH 8, then treated with $BaCl_2\;and\;CaC_2$ showed the highest purity, and the yield was $85.1\%$. 2) The same sample of $50\%$ wettable dust formulation inhibited conidial germination of P. oryzae and C. miyabeanus completely at 10 and 20 ppm, respectively. (Fig. 1) 3) The sample of $1.5\%$ dust formulation inhibited mycelial growth of P. oryzae and C. miyabeanus with 96 and $65\%$, respectively. The results were similar to those obtained by Ceresan calcium (Fig. 2) 4) Both dust and wettable powder formulations had no phytotoxcity on rice seedlings.

• Resources Recycling
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• v.11 no.1
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• pp.32-36
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• 2002

This study was conducted to compost the mixture of Pig manure, gypsum and fly ash. Initial moisture contents of sample A (Pig manure : saw dust = 6 : 4) and C (Pig manure : saw dust : gypsum : coal fly ash= 6 : 2 : 1 : 1) in the reactor were 64 and 50%. Also temperature and pH of samples in the reactor was nearly the same. Total Organic Carbon (TOC) concentration of sample A and C were about 5500, 2900 mg/kg respectively. This sample was needed a lot of time to mature as viewing cation exchange capacity (CEC) after experiment was over. However added with gypsum and coal fly ash in Process of Pig manure composting Process was suggested that gypsum and coal fly ash have a roles of additive agent.