• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.461-468
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• 2019

Demand for improving dust removal efficiency in coal power plants and the dust removal requirement to the level of capturing fine particulate matter and ultrafine particles have been increasing. While bag filter and electrostatic precipitator (ESP) are typically used for dust removal in the processes operating at atmospheric pressure, metal filters or ceramic filters are employed for dust which is produced at high temperature/pressure system as in coal gasification. For dust removal at the high temperature/pressure conditions, two metal filters of five compressed/sintered layers were manufactured and applied to analyze the dust removal characteristics. Manufactured metal filters exhibited more than 99% dust removal efficiency on coal gasification fine particulates in mass basis. To evaluate the fine particulate removal efficiency of less than $2.5{\mu}m$, JIS standard fine sample was used and confirmed the removal efficiencies of 97% and 70~82% on the fine particulates of $1{\sim}2.5{\mu}m$ size range. For the size range of less than $1{\mu}m$, dust removal efficiency of manufactured metal filters significantly degraded with smaller particle size. Improving methods are proposed to overcome the limitations in applying to fine dust of less than $1{\mu}m$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.180-183
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• 1997

The forming process of metal matrix composites by the die casting and squeeze casting process are limited in size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting, squeeze casting and compocasting. The characteristics of thixoforming process can decrease the liquid segregation because of he improvement in fluidity in a globular microstructure state and utilizes flow without air entrapment. Therefore, in order to obtain the sound parts of metal matrix composites by using thixoforming process which as co-existing solidus-liquidus pahse, it si very important to obtain reheating condition. However, for he thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.2
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• pp.103-111
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• 1998

A nondestructive ultrasonic technique is presented for estimating the reinforcement volume fractions of particulate composites. The proposed technique employs a theoretical model which accounts for composite microstructures, together with a measurement of ultrasonic velocity to determine the reinforcement volume fractions. The approach is used for a wide range of SiC particulate reinforced Al matrix ($SiC_p/Al$) composites. The method is considered to be reliable in determining the reinforcement volume fractions. The technique could be adopted in a production unit for the quality assessment of the metal matrix particulate composite extrusions.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.35-44
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• 2017

Disposal of municipal solid waste has become a major problem in many countries around the world. As landfill space for the disposal of ash from Municipal Solid Waste Incineration (MSWI) becomes scarce, numerous reports and researches address the various environmental issues about the municipal solid waste incineration waste management and other particulate matters with the range of 10 ~ 2.5. Although in many developing and industrialization countries landfill with the disposal of municipal solid waste, open incineration has become a common practice. Large municipal waste incinerators are major industrial facilities and have the potential to be significant sources of environmental pollution. Despite the significant volume reduction from incineration, waste recycling is important to ensuring the future welfare of mankind. The main goal of the present work is the physical and chemical characterization of the local incineration bottom ash towards its eventual re-utilization. In this paper, we reported the studies on physical and chemical characteristics of municipal solid waste incineration (MSWI) fly ash and bottom ash containing particulate matter whose particulate sizes are lower than $PM_{10}$, $PM_{2.5}$ and heavy metal were investigated.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.154-160
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• 2004

The purpose of this study was to evaluate airborne concentrations and characteristics of TSP, IPM, TPM and RPM in Seoul subway stations. Sampling was performed at 14 stations from April 11 to 29, 2002. Size-selective dust concentrations and metal concentrations were measured by gravimetric method and ICP-AES, respectively. The geometric mean of TSP, IPM, TPM and RPM concentrations in Seoul subway stations were 176$\mu\textrm{g}$/㎥, 348$\mu\textrm{g}$/㎥, 158$\mu\textrm{g}$/㎥ and 104$\mu\textrm{g}$/㎥, respectively. Dust concentrations in pathway were the highest and those in lobby were the lowest. The size distribution of dusts was significantly different by location of collection. When the deposition rate into pulmonary gas exchange region was estimated by size distribution, the deposition rate of dust collected from platform was higher than those of dust collected from lobby and pathway. The lower the basement levels were, the higher the deposition rates of dusts into tracheobronchial region and gas exchange region were. Copper and iron concentrations measured in platform higher were than those in other areas.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.1
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• pp.55-62
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• 2008

This study is aimed at substantially reducing the particulate matter (dust) emission during the combustion of heavy fuel in boilers by addition of combustion improver. The combustion improver used were the oil-soluble organometallic compounds that were found to be more effective than the dispersing agents that are generally used for reducing the particulate emission. The dust reduction effect was found to depend on the active materials (metals) as well as on the organic ligand part of organometallic compounds. Acetylacetonoate and naphthenate of Fe and Ca were found to be most effective for dust reduction. Addition of Fe and Ca organometallic compounds as combustion improver in concentration of 30 ppm (metal basis) to heavy fuel oil, caused dust reduction by 50 wt% to 80 wt%.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.64-73
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• 2013

Because some particulate matter emission sources may inherently produce soluble species, or some soluble species may be produced during atmospheric transport, it is important to understand the origin of a particles's solubility when water-soluble tracers are used in source apportionment studies. Laboratory experiments were performed on three types of soils (Mongolia grassland, Mongolia desert, and Korean rural soils), to study the impact of acidification by nitric acid vapor on the solubility of metals in the soils. To achieve this goal, concentrations of water-soluble metals (Na, Mg, Al, K, Ca, Mn, and Fe) in the soils measured before and after acidification. Contributions of concentrations of water-soluble metal species before and after acidification attack to their total concentrations varied little with soil type. Concentrations of water-soluble Mg, Al, K, Ca, Mn, and Fe from the soils after interaction with nitric acid vapor increased, with significant increases in soluble Ca and Mn for all soil types suggesting soil acidification enhances the amount of leachable metal species in soil dust. There was little increase in water-soluble Na and K after acidification for each soil type. This experiment demonstrates that quantities of water-soluble metal species in particulate matter are produced under high gaseous nitric acid conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.385-388
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• 2001

In part forming process of metal matrix composites, the die casting and squeeze casting process are limited the size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting squeeze casting and compocasting. However, for the thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.233-241
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• 2021

A series of three bench-scale experiments was performed to investigate the conversion of sodium metal to sodium chloride via reactions with non-metal and metal chlorides. Specifically, batches of molten sodium metal were separately contacted with ammonium chloride and ferrous chloride to form sodium chloride in both cases along with iron in the latter case. Additional ferrous chloride was added to two of the three batches to form low melting point consolidated mixtures of sodium chloride and ferrous chloride, whereas consolidation of a sodium-chloride product was performed in a separate batch. Samples of the products were characterized via X-ray diffraction to identify attendant compounds. The reaction of sodium metal with metered ammonium chloride particulate feeds proceeded without reaction excursions and produced pure colorless sodium chloride. The reaction of sodium metal with ferrous chloride yielded occasional reaction excursions as evidenced by temperature spikes and fuming ferrous chloride, producing a dark salt-metal mixture. This investigation into a method for controlled conversion of sodium metal to sodium chloride is particularly applicable to sodium containing elevated levels of radioactivity-including bond sodium from nuclear fuels-in remote-handled inert-atmosphere environments.

• Journal of Korea Foundry Society
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• v.21 no.6
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• pp.311-321
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• 2001