• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.2
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• pp.337-348
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• 2002

Based upon literature survey and questionnaire survey, this research tries to develop four new Cleanroom Garment in semiconductor industrial environment. The designs emphasize to minimize workers disconmfort so that they can not only cover human body fully but also reduce dust as much as possible during work hour in clean room. The new designs characteristics and results from both function test and dust emission test are as follows: 1. In order to reduce dust-emission, we develop new designs with hood, kimono sleeve, and back zipper. The designs with hood face positive test results in term of motion suitability and dust-omission. The design with seam in front, in particular, is effective to control dust-emission. 2. For the purpose of reducing dust-emission, we also emphasize to minimize ease of dust-proof wear, with reference to previous research and clothing experiment. The experiment participants report that the new wears are not so comfortable as existing ones, but they accept the new wears positive as effective in reducing dust-emission owing to reduced ease of Cleanroom Garment and sleeves. 3. A1so to reduce dust-emission in inner wear, we put inner wear in both Cleanroom Garments and inner wear, resulting to remove discomfort of wearers when changing clothes and of tight waist due to inner-trousers. 4. We develop new designs with elastic bands in both waist through the side lines and with velcro only at the back side. To remove twist in front contributes to reduce emission arising out of friction, also to free the appearance minding woman workers from worrying about exposed stomach. The new designs need to be accepted as a valuable alternative of Cleanroom Garment, in that they are highly effective to reduce dust-emission, which is the most important factor in the wear, in spite of some drawbacks in terms of motion-suitability, ease and appearance as shown in wearing test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.103-111
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• 2022

Fine dust can cause serious problems to human health, and fugitive dust generated at construction sites is one of the main sources of fine dust in Korea. However, monitoring of the amount of fugitive dust generated at the ready-mixed concrete plant site is not performed, and only passive monitoring methods are partially applied in the field. Since it is impossible to control fugitive dust after it is exposed to the air, it is very important to suppress the occurrence or to remove it immediately at the stage of occurrence. Therefore, after identifying the characteristics through real-time monitoring in the fugitive dust generation stage, systematic management is required for suppressing or removing scattering dust in the field. In this study, the scattering dust generation characteristics were analyzed by measuring the particle mass concentration(PMC) of Fugitive dust generated at the aggregate unloading site of the ready-mixed concrete plant in real-time.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.630-637
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• 2019

Objectives: This study was performed to evaluate the secular changes in indoor airborne dust or endotoxin levels in the dust from swine confinement buildings. Indoor levels were compared with the level at the exhaust outlet in order to examine the contribution potential of indoor dust to nearby ambient air dust. Methods: Comparisons were made on inhalable and respirable dust levels reported in 2002, 2012, and 2017 from 14, 10, and 36 swine fattening confinement buildings in Korea, respectively. This data was produced by the same research group. Levels of endotoxin adsorbed into inhalable or respirable dust were also compared. Samples of inhalable or respirable dust were collected indoors and at exhaust outlets from 17 swine fattening confinement buildings in 2019, and dust levels were compared between the indoor and the outlet. Results: The outlet inhalable dust level (0.111 mg/㎥) was approximately 19% of that from indoors, and the respirable dust level (0.033 mg/㎥) was approximately 74% of that from indoors. The outlet respirable dust levels were lower than the airborne fine dust levels in the towns where those farms are located. No significant difference was observed in the inhalable dust levels among the years examined, but the respirable dust level in 2017 (0.143 mg/㎥) was significantly lower than in 2002 (0.328 mg/㎥). The level of endotoxin in inhalable dust was significantly higher in 2017 (722 EU/㎥) than in both 2002 (75 EU/㎥) and 2012 (171 EU/㎥). Conclusion: Even though no apparent contribution from swine farm indoor dust to nearby ambient air dust was observed in terms of amount, a certain control strategy to reduce the production of airborne dust and endotoxin from swine farms is merited.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.365-369
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• 2001

EAF's dust has been treated mainly by pyrometallurgical reduction process in rotary kiln furnace to recover valuable metal elements such as Zn and to avoid the disposal of hazardous materials to waste. Recently, hydrometallurgical eletrowinning of zinc from a zinc-amino chloride solution obtained by the leaching of EAF's dust was developed to recover high grade zinc metal from EAF’s dust. But there are some disadvantages in each process such as difficulty of operation condition control and sticking problem in kiln process and low extractability and recovery of zinc owing to insoluble zinc-ferrite in electrowinning process. We propose a new combined process of pyrometallurgical one and hydrometallurgical one to treat EAF's dust efficiently and economically. In this study, ammonium chloride solution leaching of crude zinc oxide recovered from reduction of EAF's dust was carried out to find out the efficiency of zinc extraction from it and the possibility for performance of eletrowinning in the proposed process. Effects of various leaching variables ruck as leaching temperature, concentration of leaching solution and leaching time were investigated. And the leaching results of the crude zinc oxide were compared with those of EAF's dust. The extraction percents of zinc in ammonium chloride solution leaching of the crude zinc oxide recovered from reduction of EAF's dust were above 80% after 60 minutes of leaching under the leaching condition of 4M NH$_4$CI concentration and above leaching temperature of 7$0^{\circ}C$. And the concentrations of zinc in the leached solution were obtained above 50g/$\ell$. The activation energy calculated for zinc extraction in NH$_4$CI leaching was 58.1 KJ/㏖ for EAF's dust and 15.8 KJ/㏖ for the crude zinc oxide recovered from reduction of EAF's dust.

• Biomedical Science Letters
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• v.22 no.4
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• pp.211-214
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• 2016

House dust mite is an essential allergen in the pathogenesis of allergic diseases. Abnormal regulation of neutrophil apoptosis is an important pathogenic process in allergic diseases. In the present study, we investigated the effects of house dust mites on spontaneous apoptosis of neutrophils and its associated mechanisms. Extract of Dermatophagoides pteronissinus (DP) inhibited neutrophil apoptosis in a time-dependent manner. Cycloheximide (CHX), an inhibitor of translation, increased apoptosis of DP-treated neutrophils as well as control cells. The pro-apoptotic effect of CHX was blocked by DP in neutrophils. In addition, DP increased the phosphorylation of Bad in a time-dependent manner, indicating that it exerted an inhibitory effect on the function of Bad. These results suggest that DP has anti-apoptotic effects of neutrophils and may regulate protein synthesis and activation of Bad. Moreover, these findings may shed light on elucidation of allergy pathogenesis due to house dust mites.

• Journal of Conservation Science
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• v.35 no.3
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• pp.227-235
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• 2019

In Korea, various methods are applied to prevent wooden structures from being damaged by termites. However, since there is no way to quickly bring toxic substances in contact with the termites inside the timber, it leads to the damage of wooden cultural property due to the prolonged period of controlling the termites. Accordingly, an indoor evaluation criteria study was conducted for the introduction of powder-type termiticides in Korea, which produced rapid control effects by drilling wood and directly contacting and transferring toxic substances inside the timber. First, contact toxicity and transfer ability of termite dusts were evaluated to establish the criteria for evaluation of effectiveness against Reticulitermes speratus. The contact toxicity confirmed 100% mortality of fipronil, deltamethrin and cyfluthrin termite dusts within 24 h of contact; however, differences occurred in the active ingredient transfer time to the sublethal. In addition, in the case of transfer ability evaluation, the rate of mortality gradually decreased under 1:9 and 1:25 ratio conditions; however, the difference in the reduction rate was identified depending on the type of termite dust. the results of the evaluation of compressive strength of the wood showed that the difference in the measured values between the control group and the conditions of perforation 1 to 3 times, which does not significantly affect the compressive strength of wood. In this study, the criteria of termite dust selection and evaluation method of dust-type termiticides were presented and the applicability of the method was identified.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.158-166
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• 1999

The purpose of this study was to investigate the correlation between airborne total dust and man-made mineral fibers (MMMF), and to estimate total dust concentration to maintain below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV$^{(R)}$) for the MMMF. The regression coefficients between airborne total dust concentrations and fiber concentrations determined in the industries producing glass fibers, rock wool. refractory ceramic and continuous filament glass fibers products were 0.41, 0.42, 0.20 and 0.19, respectively. The size characteristics of fibers as well as the amounts of contaminated non-fibrous dusts could affect the correlation intensities. When total dust and fiber exposure data were compared with the occupational exposure limits, there was a large gap between two evaluation results. The regression coefficient between total dust and fiber data was increased ($r^2=0.88$) in the process of insulation installation generating in the higher levels of glass or rock wool fibers. In this case, an estimated total dust concentration of glass wool or rock wool fibers complying with the ACGIH TLV (1 f/cc) was $1.7mg/m^3$. In conclusion, the total dust and fibers concentrations was highly correlated at the higher exposure levels so that total dust-monitoring data could be used to control simply and economically and to estimate worker's exposure to fibers.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2007.05a
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• pp.230-234
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• 2007

• 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.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.110-120
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• 2005

For utilizing vitrification to treat low and intermediate level waste, industrial pilot plant was designed and constructed in October 1999 at Daejon, Korea through the joint research program among NETEC, MOBIS and SGN. More than 70 tests were performed on simulated IER, DAW etc. including key nuclide surrogate(Cs, Co); this plant has been shown to vitrify the target waste effectively and safely, however, some dust are generated from the HTF(High Temperature Filter) as a secondary waste. In case of long term operation, it is also concerned that pipe plugging can be occurred due to deposited dust in cooling pipe namely, connecting pipe between CCM(Cold Crucible Melter) and HTF. In this regard, we have developed the special complementary system of the off-gas treatment system to recycle the dust from HTF to CCM and to remove the interior dust of cooling pipe. Main concept of the dust recycling is to feed the dust to the CCM as a slurry state; this system is regarded as of an important position in the viewpoint of volume reduction, waste disposal cost and glass melt control in CCM. The role of DRS(Dust Recycling System) is to recycle the major glass components and key nuclides; this system is served to lower glass viscosity and increase waste solubility by recycling B, Na, Li components into glass melt and also to re-entrain and incorporate into glass melt like Cs, Co. Therefore dust recycling is helpful to control the molten glass; it is unnecessary to consider a separate dust treatment system like a cementation equipment. The effects of Dust Cleaner are to prevent the pipe plugging due to dust and to treat the deposited dust by raking the dust into CCM. During the pilot vitrification test, overall performance assessment was successfully performed; DRS and Dust Cleaner are found to be useful and effective for recycling the dust from HTF and also removing the dust in cooling pipe. The obtained operational data and operational experiences will be used as a basis of the commercial facility.