• International Journal of Safety
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• v.4 no.1
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• pp.18-22
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• 2005

A model was proposed for investigating the particle removal from suspension with particles of different sizes by deep-bed filtration, and the collection efficiency was predicted by computer simulation. Deposited particles on the pore surface may act as additional collector and reduce the pore size, which contribute to the improved collection efficiency with increase of deposition. Computer experiments for suspension of particles of three sizes and its equivalent size of mono particles were carried out and compared. The collection efficiency of suspension with poly-dispersed particles shows higher efficiency than that of suspension with mono-dispersed particles. Also the collection efficiency of smell particle of mixture is higher that that of same uniform size particles.

• Membrane Journal
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• v.20 no.2
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• pp.87-96
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• 2010

We prepared spherical silica particles by controlling various conditions of emulsion-gel procedure using a lab-scale membrane emulsification system equipped with SPG (Shirasu porous glass) membrane having pore size of 2.6 ${\mu}m$. We determined the effects of process parameters of membrane emulsification (dispersed phase pressure, stabilizer and emulsifier concentration in continuous phase, $H_2O$/TEOS ratio, ratio of dispersed phase to continuous phase) on the mean size and size distribution of silica particles. The increase of the dispersed phase pressure and ratio of dispersed phase to continuous phase led to the increase in the mean size of silica particles. On the contrary, the increase in stabilizer and emulsifier concentration and $H_2O$/TEOS ratio caused the reduction of the mean size of particles. Through controlling these parameters, monodisperse spherical silica particles with about 3 ${\mu}m$ of the mean size were finally prepared.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3464-3471
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• 2023

The Uranium/Molybdenum metallic fuel has been proposed as promising advanced fuel concept especially in the dispersed fuel geometry. The fuel is manufactured in the form of small fuel droplets (particles) placed in a fuel pin covered by a matrix. In addition to fuel particles, the pin contains voids necessary to compensate material swelling and release of fission gases from the fuel particles. When investigating this advanced fuel design, two important questions were raised. Can the dispersed fuel performance be analyzed using homogenization without significant inaccuracy and what size of fuel drops should be used for the fuel design to achieve optimal utilization? To answer, 2D burnup calculations of fuel assemblies with different fuel particle sizes were performed. The analysis was supported by an additional 3D fuel pin calculation with the dispersed fuel particle size variations. The results show a significant difference in the multiplication factor between the homogenized calculation and the detailed calculation with precise fuel particle geometry. The recommended fuel particle size depends on the final burnup to be achieved. As shown in the results, for lower burnup levels, larger fuel drops offer better multiplication factor. However, when higher burnup levels are required, then smaller fuel drops perform better.

• Journal of the Korean Ceramic Society
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• v.37 no.2
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• pp.152-157
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• 2000

Si3N4/SiC nanocomposite ceramics containing 5 wt%dispersed SiC particles were prepared by gas-pressure-sintering at 200$0^{\circ}C$ under nitrogen atmosphere. SiC particles with average sizes of 0.2 and 0.5${\mu}{\textrm}{m}$ were used, and the effect of the SiC particle size on the microstructure was investigated. The addition of SiC particles effectively suppressed the growth of the Si3N4 matrix grains. The effect of grain growth inhibition was higher in the nanocomposites dispersed with fine SiC. SiC particles were dispersed uniformly inside Si3N4 matrix grains and on grain boundaries. When the fine SiC particles were added, large fraction of the SiC particles was trapped inside the grains. On the other hand, when the large SiC particles were added, most of the SiC particles were located on grain boundaries. Typically, the fraction of SiC particles located at grain boundaries was higher in the specimen prepared from $\beta$-Si3N4 than in the specimen prepared from $\alpha$-Si3N4.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.52-69
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• 1996

Nano-Sized TiO$_2$ particles with diameter between 2 and 5 nm are synthesized in Water/Triton X-100/n-Hexane microemulsion. Particles show the amorphous structure and partially hydroxide form. The optical absorbance of particles appears at 250nm and band edge at 340nm. Gold metal is deposited on the surface of TiO$_2$ particles by reduction reaction of Au(III) ion with sodium hypophosphite. The size of gold-deposited particles is 20nm, and the optical absorbance appears at 270nm and at 550nm. So particles show the red color. The dense precipitation is formed by aggregation in the TiO$_2$ nano-sized particles of about 5nm size. But the bulky precipitation is formed by agglomeration phenomena in the gold-deposited particles of 20nm size. And also gold-deposited particles is easily dispersed by being re-dispersed in PEG/Water solution. This study has compared those things measuring the SPF characteristics of the cosmetics made of the synthesized particles. If the particle size is controlled appropriately, then the SPF value will be higher, or more colorless cosmetics will be made.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.183-186
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• 2004

Nano particles-containing CMS membranes were prepared by pyrolysis of polyimides dispersed uniformly with precursors and their gas separation performances were examined, to elucidate the permeation mechanism and to further improve the gas separation performance. Consequently, it was suggested that the separation performance could be controlled by doping nano-particles in the CMS membranes, and that optimization of various factors, such as the size, content, and dispersion state of the nano particles would contribute for further improvement of the gas separation performance.

• Korea-Australia Rheology Journal
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• v.13 no.3
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• pp.125-130
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• 2001

Block copolymers of PC-b-PMMA (polycarbonate-b-polymethylmethacrylate) and PC -b-SAN (polycarbonate-b-(styrene-c-acrylonitrile)), were examined as compatibilizers for blonds of PC with SAN copolymer. The average diameter of the dispersed particles was measured with an image analyser, and the interfacial properties of the blonds were analysed with an imbedded fiber retraction (IFR) technique. The average diameter of dispersed particles and interfacial tension of the PC/SAN blends reached a minimum value when the SAN copolymer contained about 24 wt% AN. Interfacial tension and particle size were further reduced by adding compatibilizer to the PC/SAN blends. PC-b-PMMA was more effective than PC-b-SAN as a compatibilizer in reducing the average diameter of the dispersed particles and interfacial tension of PC/SAN blend. A direct proportionality between the particle diameter and interfacial tension was also observed. The interfacial properties of the PC/SAN blends were optimized by adding a block copolymer and using an SAN copolymer that had minimum interaction energy with PC.

• Journal of the Korean institute of surface engineering
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• v.25 no.4
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• pp.165-172
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• 1992

Filler, popularly used in the polymer materials, was dispersed randomly and irregularly. For the study of dispersed behavior, the specimen which have two particles in polystyrene was prepared. And the tensile strength, modulus and SEM picture were measured. When the distance between particles increased, the tensile strength and modulus increased, but particle size did not affect the values. And when the am-bient temperature increased, the tensile strength and modulus decreased, but the distance did not affect the tensile strength and modulus.

• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1011-1016
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• 2002

Colloidal particles of silica (100 nm in size) were electrostatically dispersed and adsorbed on a glass substrate coated with silica sol or alumina sol. Stability of the suspensions and microstructure of the adsorbed particle layers were discussed in terms of total potential energies between the particles and the substrate. Well-dispersed suspension resulted in a layer with densely packed and regularly arranged particles, whereas less stable suspension resulted in a porous layer with loosely packed and irregularly arranged particles. Despite repulsive interactions between the particles and the substrate coated with silica sol, the observed adsorption can be attributed to chemical bonds formed at the interface between the particle and silica sol. In contrast, the adsorption of the particles on the substrate coated with alumina sol formed a layer with strongly adhered and densely packed particles, due to large attractive interactions between the particles and alumina sol.

• Elastomers and Composites
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• v.31 no.5
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• pp.327-334
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• 1996

A correlative analysis has been carried out to predict the average particle size of rubber dispersed phase In high impact polystyrene manufactured by bulk polymerization. To do the correlation, a mechanistic model suggested previously by the author was used for describing the size of stabilizing particles agitated under the turbulent viscous shear subranges in a prepolymerization reactor, where the rubber particles were assumed to be formed at the time of phase inversion in the reactor. Viscosities required for the model were postulated to describe the overall behavior of butadiene rubber and polystyrene mixture along the wide range of conversion. The good agreement between the model and the experimental data from a plant was quite satisfactory for the prediction of the average rubber particle size of high impact polystyrene.