• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.669-674
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• 2001

Electric Arc Furnace Dust (EAF Dust) Is residual dust produced during the manufacturing of metal products from heavily heated electric arc furnace. Many researches have focused on recycling and reusing EAF Dust for industrial and construction purposes. However, most of these researches were aimed at obtaining useful heavy metal powders by treating toxic metallic materials in EAF Dust. Also, few researches dealt with using EAF Dust as admixture in concrete mixture (i.e., slag dust). In this study, EAF Dust is used as admixture in concrete mixture content considering economical feasibility and construction applicability. The concrete specimens mixed with EAF Dust is then tested in compression and tension to study its strength and ductility as well as its failure mechanism. The compression and tension (by split cylinder test) test results are compared to the results from the specimens without EAF Dust to understand the chemical stability and mechanical characteristic of concrete specimens with EAF Dust. For the experiment, 6 types of admixture added concrete were studied: ⑴Combination of EAF Dust and blast-furnace slag in 1 to 1 ratio, ⑵Combination of EAF Dust and blast-furnace slag in 1 to 2 ratio, ⑶EAF Dust only, ⑷blast-furnace slag only, ⑸fly ash only, and ⑹no admixture. The experimental results show that the strength of EAF Dust added specimen has lower early age strength but higher 28 day strength when compared to other specimens. Also, the Elastic Modulus of EAF Dust is higher(28 days) than other specimens. The study results prove that EAF Dust can be used as an effective admixture in concrete for specific usages.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.145-157
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• 1999

Wood dust is created when machines are used to cut or shape wood materials. Industries of high risk of wood dust exposure are sawmills, dimension mills, furniture industries, and carpenters, etc. Health effects associated with wood dust exposure includes dermatitis, allergic respiratory effects and cancer. Health effects of wood dus t are mainly depend on the concentration, dust size and exposure time. This study were carried out to evaluate the concentration and particle size distribution of wood dust during working processes. The subjects of this study were 53 workers exposed to wood dust in 7 furniture factories and 5 musical instruments, and 5 sawmill factories. The average total wood dust concentrations measured by personal cascade impactor were $1.82{\pm}2.31mg/m^3$ in primary manufacture, $3.59{\pm}1.72mg/m^3$ in s econdary manufacture, $5.09{\pm}1.46mg/m^3$ in sanding operation. Mass median diameters of hardwoods dust were $3.36{\mu}m$ in primary manufacture, $4.25{\mu}m$ in secondary manufacture, $4.21{\mu}m$ in sanding operation. softwoods dust were $3.39{\mu}m$ in primary manufacture, $4.34{\mu}m$ in secondary manufacture. Particle size distributions showed a nearly the same pattern in each working processes. The sample concentration of all hardwood dust exceeded the Threshold Limit Value(TLV) and 20.8% of the softwood dust exceeded the Threshold Limit Value. The range of size distribution were $0.5-10{\mu}m$ in the soft and hardwood dust. The respirable dust of soft and hardwood took up 59% and above. Therefore new threshold limit value for wood dust should be needed in Korea. Also, it should be done for various studies on health effects related to occupational exposure of wood dust.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.289-294
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• 2004

The main sources of interstellar dust are believed to be dust envelopes around AGB stars. The outflowing envelopes around the long period pulsating variables are very suitable place for massive dust formation. Oxygen-rich silicate dust grains or carbon-rich dust grains form in the envelopes around AGB stars depending on the chemical composition of the stellar surface. The dust grains expelled from AGB stars get mixed up and go through some physical and chemical changes in interstellar medium. There are similarities and differences between interstellar dust and dust grains in AGB stars. The mass cycle in the Galaxy may be best manifested by the fact that the dust grains at various regions have many similarities and understandable differences.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.48-54
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• 2020

Researchers recognized air pollution changes causing diseases and difficulties in living due to environmental pollution following various human activities, and have studied how to avoid fine dust harmful to the human respiratory system to be healthy. To this end, Arduino is used to equip fine dust level sensors in drones to measure the fine dust levels, visualize the measurements with LED indicator colors depending on the measurements to inform users of the danger of fine dust, and use the benefits of drones to specify dangerous fine dust zones and measure the fine dust levels. Users can see the changes depending on the fine dust levels in real time with the LED indicators. This will contributes to measuring fine dust levels easily in dangerous areas. Mission Planner (ArduPilot) is used to set up the GPS of drone, and store the data from the dust sensor as contents. This study aims to establish a method for improving the environment to measure fine dust levels with drones with LED indicators for fine dust, and reduce fine dust.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.89-94
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• 1999

The paper first proposes an empirical algorithm for detecting dust-loaded airmass observed by Sea Wide Field-of-view Scanner (SeaWiFS). The proposed dust index formula is based on the curvature of the spectral reflectance estimated from the SeaWiFS band 4 (510 nm band) through band 8 (865 nm band) data, assuming "clear ocean water" reflectance. Evaluation of the algorithm is made over several typical Asian dust images including the ones over the Pacific in April, 1998, when a major dust event was reported. The study analyzes the performance and the characteristics of the algorithm by comparing the satellite-derived dust index images with contemporaneous columnar concentration of dust particles predicted by a numerical dust transport model. The comparison reveals several small-scale differences although their dust distribution patterns show good agreement generally.

• Journal of The Korean Astronomical Society
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• v.44 no.1
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• pp.13-21
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• 2011

We model dust around Herbig Ae/Be stars using a radiative transfer model for multiple isothermal circumstellar dust shells to reproduce the multiple broad peaks in their spectral energy distributions (SEDs). Using the opacity functions for various types of dust grains at different temperatures, we calculate the radiative transfer model SEDs for multiple dust shells. For eight sample stars, we compare the model results with the observed SEDs including the Infrared Space Observatory (ISO) and AKARI data. We present model parameters for the best fit model SEDs that would be helpful to understand the overall structure of dust envelopes around Herbig Ae/Be stars. We find that at least four separate dust components are required to reproduce the observed SEDs. For all the sample stars, two innermost dust components (a hot component of 1000-1500 K and a warm component of 300-600 K) with amorphous silicate and carbon grains are needed. Crystalline dust grains (corundum, forsterite, olivine, and water ice) are needed for some objects. Some crystalline dust grains exist in cold regions as well as in hot inner shells.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.30-37
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• 2022

Because fine dust (PM10) has a close effect on the environment, fine dust generated in the climate and living environment has a bad effect on the human body. In this study, the LSTM model was applied to predict and analyze the effect of fine dust on Gwangju Metropolitan City in Korea. This paper uses prediction values of input variables selected through correlation analysis to confirm fine dust prediction performance. In this paper, data from the Gwangju Metropolitan City area were collected to measure fine dust. The collection period is one year's worth of data was used from january to December of 2021, and the test data was conducted using three-month data from January to March of 2022. As a result of this study, in the as a result of predicting fine dust (PH10) and ultrafine dust (PH2.5) using the LSTM model, the RMSE was 4.61 and the test result value was as low as 4.37. This reason is judged to be the result of the contents of the one-year sample.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.38-39
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• 2020

Since a lot of fugitive dust is generated at construction and civil engineering construction sites in Korea, the fine dust regulation at construction sites has been strengthened in accordance with the implementation of the Special Act on Fine Dust Reduction. In a construction site, water is generally sprayed to temporarily reduce the generation rate of scattered dust, but there is a problem that when water evaporates, it scatters again. In this study, the performance of a scattering dust inhibitor incorporating a polymer that stabilizes the ground and reduces the rate of scattering dust by forming a polymer film even when water evaporates using a polymer and a surfactant was evaluated.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.10-17
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• 2020

Objectives: This study was performed to evaluate the total dust, size-selective dust, and heavy metal concentrations generated inside and outside toll booths on an expressway and to identify the source through analysis of the components of the deposited dust. Methods: A total of 32 samples were collected from eight expressway toll booths. Each total dust sample was collected using a 37 mm PVC filter attached to a personal air sampler. Heavy metal samples were collected according to NIOSH method 7300. The size-selective dust concentrations were identified using a DustMate, and deposited dust was analyzed by WD-XRF and UHR-FE-SEM. Results: The geometric mean concentrations of the total dust inside and outside the toll booths were 337.5 ㎍/㎥ and 342.7 ㎍/㎥, respectively. The overall concentrations of TSP, PM₁₀, PM_2.5, and PM1 were higher on the outside of the toll booths, as the particle size of dust was larger, and higher in the underground passage as the dust size was smaller. The real-time analysis of the dust concentrations of TSP, PM₁₀, PM_2.5, and PM1 revealed to be higher at morning and evening times than other times because of heavy traffic. The element components of deposited dust in the toll booth were related to natural sources rather than artificial sources. Among the chemical components in the deposited dust analyzed by WD-XRF, SiO₂ was the highest. For the elements analyzed by UHR-FE-SEM, C was the highest, followed by O, and Si. Conclusions: In order to reduce the dust concentrations around toll booths on an expressway, it is necessary to periodically clean surrounding areas such as underground passages, and it is also necessary to remove deposited dust inside the toll booth from time to time.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.573-583
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• 2005

Fugitive dust, which is emitted in the ambient air without first passing through a stack or duct designed to control flow, is frequently generated by means of wind erosion from storage yards at Pohang Steel Wokrs. The size distribution of fugitive dust is mostly in the range of coarse particulate which is deposited as soon as emitted and less harm to human health; however $20\%$ of fugitive dust contains PM 10 known as one of most harmful airborne pollutant. Consequently, effective control and reduction of fugitive dust is strongly requested by the local society, but it is not easy so far because the generation and dispersion of fugitive dust highly depends on meteorological conditions, and it being occurred for irregularity. This research presented a fugitive dust control system for each meteorological condition by providing statistical prediction data obtained from a statistical analysis on the probability of generating the threshold velocity at which the fugitive dust begins to occur, and the frequency occurring by season and by time of the wind direction that can generate atmospheric pollution when the dispersed dust spreads to adjacent residential areas. The research also built a fugitive dust detection system which monitors the weather conditions surrounding storage yards and the changes in air quality on a real-time basis and issues a warning message by identifying a situation where the fugitive dust disperses outside the site boundary line so that appropriate measures can be taken on a timely basis. Furthermore, in respect to the spraying of water to prevent the generation of fugitive dust from the storage piles at the storage yard, an advanced statistical meteorological analysis on the weather conditions in Pohang area and a case study of fugitive dust dispersion toward outside of working field during $2002\∼2003$ were carried out in order to decide an optimal water-spraying time and the number of spraying that can prevent the origin of fugitive dust emission. The results of this research are expected to create extremely significant effects in improving surrounding environment through actual reduction of the fugitive dust produced from the storage yard of Pohang Steel Works by providing a high-tech warning system capable of constantly monitoring the leakage of fugitive dust and water-spray guidance that can maximize the water-spraying effects.