• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.679-686
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• 2018

A new dust cleaning vehicle is needed to remove fine and ultra-fine particulate matter in subway tunnels. Therefore, the recently developed tunnel cleaning vehicle is equipped with an efficient suction system and cyclone-based prefilter to handle ultra-fine particles. To treat various sizes of particulate matter with an underbody suction system, this paper proposes a cyclone-based prefilter in the suction system and validates the dust removal efficiency through Computational Fluid Dynamics (CFD) analysis using ANSYS FLUENT. Using the created surface and volume mesh, various particle sizes, materials, and fan flow rates, the particles were tracked in the flow with a discrete phase model. As a result, the dust cleaning vehicle at a normal operational speed of 5km/h requires at least a fan flow rate of $1500m^3/min$ and 100mm of suction inlet height from the tunnel track floor. Those suction modules and cyclone-based prefilters in the dust cleaning vehicle reduces the dust accumulation load of the electric precipitator and helps remove the accumulated fine and ultra-fine dust in the subway tunnel.

• Particle and aerosol research
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• v.6 no.4
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• pp.151-164
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• 2010

Inorganic ions and water are major components of ambient fine particles. Water content in fine particles is mainly determined by ambient meteorological conditions and the concentrations of hygroscopic species such as inorganic ions. Thus, to reduce fine particle mass concentration, it is important to accurately estimate the relationship between water content and the concentration of ions in fine particles. Water content in fine particles in Seoul are estimated by using a gas/particle equilibrium model to understand the characteristics of fine particle mass concentration. In addition, sensitivity of fine particle mass concentration to the changes of particulate ionic species (sulfate, nitrate, and ammonium) is estimated. It was found that water content in Seoul is mostly determined by the concentrations of the hygroscopic ionic species, especially, sulfate and ammonium, and ambient relative humidity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.60-61
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• 2020

In this study, the recycled fine aggregates produced from the waste concrete by using Jaw crusher depending on crushing gap of Jaw crusher were studied to offer a solution for recycled fine aggregate for concrete. The results of the experiment showed that the factors that influence grading and water absorption ratio, density and grain shape were significantly characterized by the generation of the particulate matter and the crushing shape of the aggregate.

• Particle and aerosol research
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• v.5 no.4
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• pp.179-188
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• 2009

The dry deposition fluxes of particulate polychlorinated biphenyls (PCBs) were measured along with their mass size distributions at Seoul and Incheon in fall in 1999. The dry deposition fluxes of PCBs were in the range of $16.7{\sim}62.2ng/m^2/day$. The ambient concentrations of particulate PCBs were in the range of 0.07 to $0.20ng/m^3$. Generally, the mass size distribution of particulate PCBs shows bi-modal distribution. The mass fraction of PCBs in the fine particle fraction ($D_p<2.1 {\mu}m$) was over than 55% of the total PCBs concentrations. It was found that Seoul and Incheon were not the major source of PCBs emissions in Korea. Based on the comparison with the measurement data in summer, 1999, it is likely that both the dry deposition fluxes and ambient particulate PCBs concentrations were not site-specific.

• International Journal of Automotive Technology
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• v.3 no.1
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• pp.1-8
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• 2002

There is Increasing world-wide interest in diesel particulate filters (DPF) because of their proven effectiveness in reducing exhaust smoke and particulate emissions. Fine particulates have been linked to human health . DPF use requires a means to secure the bum-out of the accumulated soot, a process called regeneration. If this is not achieved, the engine cannot continue to operate. A number of techniques are available, but most are complex, expensive or have a high electrical demand. The use of fuel additives to catalyse soot bum-out potentially solves the problem of securing regeneration reliably and at low cost. Work on organo-metallic fuel additives has shown that certain metals combine to glove exceptional regeneration performance. Best performance was achieved with a combination of iron and strontium based compounds. Tests were carried out un a bed engine and on road vehicles, which demonstrated effective and reliable regeneration from a tow dose fuel additive, using a single passive DPF. No control valves, flow diverters. heaters or other devices were employed to assist regeneration. Independent particle size measurements showed that there were no harmful side effects from the use of the iron-strontium fuel additive.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2107-2115
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• 2018

Over recent years, high-concentration of particulate matters (e.g., a.k.a. fine dust) in South Korea has increasingly evoked considerable concerns about public health. It is intractable to track and report $PM_{10}$ measurements to the public on a real-time basis. Even worse, such records merely amount to averaged particulate concentration at particular regions. Under this circumstance, people are prone to being at risk at rapidly dispersing air pollution. To address this challenge, we attempt to build a predictive model via deep learning to the concentration of particulates ($PM_{10}$). The proposed method learns a binary decision rule on the basis of video sequences to predict whether the level of particulates ($PM_{10}$) in real time is harmful (>$80{\mu}g/m^3$) or not. To our best knowledge, no vision-based $PM_{10}$ measurement method has been proposed in atmosphere research. In experimental studies, the proposed model is found to outperform other existing algorithms in virtue of convolutional deep learning networks. In this regard, we suppose this vision based-predictive model has lucrative potentials to handle with upcoming challenges related to particulate measurement.

• Journal of Hydrogen and New Energy
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• v.13 no.1
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• pp.34-41
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• 2002

CdS and $TiO_2$ nanoparticles were made by the precipitation method and sol-gel method, respectively, and they were mixed mechanically and then treated with the hydrothermal processing. CdS-$TiO_2$ composite particulate films were thus prepared by casting CdS-$TiO_2$ mixed sol onto $SnO_2$ conducting glass and a subsequent heat-treatment at $400^{\circ}C$. Again, the physico-chemical and photoelectrochemical properties of these films were controlled by the surface treatment with $TiCl_4$ aqueous solution. The photocurrents and the hydrogen production rates measured under the present experimental conditions varied in the range of $3.5{\sim}4.5mA/cm^2$ and $0.3{\sim}1.8cc/cm^2$-hr, respectively, and showed the maximum values at the $CdS/[CdS+TiO_2]$ mole ratio of 0.2. Also, the surface treatment with $TiCl_4$ aqueous solution caused a considerable improvement in the photocatalytic activity, Probably as a result of close contacts between the primary particles by the etching effect of $TiCl_4$ It was found that the photoelectrochemical performance of these particulate films could be effectively enhanced by this approach.

• Journal of environmental and Sanitary engineering
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• v.24 no.4
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• pp.60-68
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• 2009

The most principal approach to improve indoor air quality(IAQ) of subway was to examine the fine particulate(PM-10) from the emission sources. Therefore, this study was carried on the investigation the fine particulate for comparison with the removal efficiency of PM-10 in divided the PSD(Platform Screen Door) and Non-PSD subway station from July, 2007 to May 2008. In the monitoring results, the range of PM-10 concentration of Non-PSD station was $44.6{\sim}116.5{\mu}g/m^3$ and the range of PM-10 concentration of PSD station was $23.9{\sim}81.1{\mu}g/m^3$. And then the range of PM-2.5 concentration of Non-PSD station was $17.4-56.6{\mu}g/m^3$, and then the range of PM-2.5 concentration of PSD station was $17.9{\sim}34.4{\mu}g/m^3$. In comparison with the results of the PSD and Non-PSD subway station, we found that the PM-10 removal efficiency of PSD was 30-40%. In conclusion, the PSD will be applied the effective facilities of decreasing PM-10 in subway station in Korea.

• Journal of Hydrogen and New Energy
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• v.13 no.3
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• pp.224-232
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• 2002

CdS-$TiO_2$ nano-composite sol was prepared by the sol-gel method in organic solvents at room temperature and further hydrothermal treatment at various temperatures to control the physical properties of the primary particles. Again, CdS-$TiO_2$ composite particulate films were made by casting CdS-$TiO_2$ sols onto $F:SnO_2$ conducting glass and then heat-treatment at $400^{\circ}C$. Physical properties of these 61ms were further controlled by the surface treatment with $TiCl_4$, aqueous solution. The photo currents and hydrogen production rates measured under the experimental conditions varied according to the $CdS/[CdS+TiO_2]$ mole ratio and the mixed-sol preparation method. For $CdS-TiO_2$ composite sols prepared in IPA, CdS particles were homogeneously surrounded by $TiO_2$ particles. Also, the surface treatment with $TiCl_4$ aqueous solution caused a considerable improvement in the photocatalytic activity, probably as a result of close contacts between the primary particles by the etching effect of $TiCl_4$. It was found that the photoelectrochemical performance of these particulate films could be effectively enhanced by this approach.

• Land and Housing Review
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• v.12 no.2
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• pp.91-97
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• 2021

High levels of fine dust is an increasing health concern in major cities such as Seoul. To improve the indoor air quality of apartments, this study examined the ability of an air shower system installed in an apartment unit to remove fine dust (as defined by ISO 12103-A2) from various clothing items of building occupants entering their apartment. Results of the experiment indicate that an air shower system is effective in removing final dust from clothing after one pass through the system. The fine dust removal efficiency for various clothing items was 74% for a dress suit, 70.6% for hiking clothes, 63.3% for knit-wear, 50.5% for a cotton t-shirt, and 38.8% for a coat. Fine dust removal efficiency increased with a second and third pass through the air shower system by an average of 9.1 and 13.9 percentage points respectively compared to a single pass through the system.