• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.26-34
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• 1999

This paper was intended to find out the relationship between optical and interior properties of coated paper and printability with the variation of particle size of ground calcium carbonate(GCC) by using Mercury Porosimeter, and to find out the pore properties of coated paper as well. The viscosity and water retention of coating color was increased and smothness, sheet gloss and porosity of coated paper were improved as the particle size of GCC was decreased. However, there was no difference in opacity and brightness of coated paper. The pore volume of coated paper was decreased, but the number of pores was drastically increased according to the decrease of the particle size of GCC. The weight of ink transferred into coated paper was increased in proportion to pore volume of coated paper. However, the weight of damping water and ink induced toward coated paper was slightly increased. Ink setting was accelerated printing gloss was not changed. Therefore, optical and interior properties of coated paper seemed to be affected by the pore property of coated paper and printability was also affected by it.

• Journal of Applied Reliability
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• v.16 no.2
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• pp.155-161
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• 2016

Purpose: Purpose of this study is to analyze the effect of particle size as well as number of pass on surface microstructure and hardness of SiC(p)/AZ31 surface composite fabricated by friction stir process (FSP). Method: SiC(p)/AZ31 surface composite containing different size of SiC particle (i. e., $2{\mu}m$ and $8{\mu}m$) was fabricated by multi-pass FSP. Microstructure was observed by scanning electron microscope and surface hardness was determined by Vickers hardness tester. Results: For all the FSPed specimens with and without hardening particles, grain size was refined due to dynamic recrystallization behavior. Surface hardness was observed to increase with decreasing particle size in the composite layer. Increasing number of FSP pass was effective for homogeneous distribution of the hardening particles and for resulting increase in surface hardness. Conclusion: FSP was effective to modify surface microstructure for improving surface hardness of SiC/AZ31 composite.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.833-838
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• 2008

Size effects of rice product powders on physical properties including suspension stability were investigated in this study. Endosperm, bran, and husk powders of rice with different size particles were prepared using the pin crusher or the ultrafine air mill. The physical properties of the powders were examined using particle size analysis, scanning electron microscopy, and spectrophotometry. The peak of the volume-weighted particle distribution of ultrafine endosperm particles was at $5.4\;{\mu}m$ whereas those of the bran and the husk appeared at 65 and $35\;{\mu}m$, respectively. Ultrafine particles of the endosperm and the husks dispersed better than larger-sized particles. As time elapsed, the dispersibility decreased, but the ultrafine particles were precipitated at the slowest rate. Our results suggest that ultrafine particles, including future nanosized particles, provide improved solubility and dispersibility resulting in better stability in the food colloidal suspension.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.286-293
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• 2020

Objective: Two experiments were conducted to evaluate the effects of corn particle size and lipid form on the apparent total tract digestibility (ATTD) of energy and nutrients in diets for growing pigs. Methods: In Exp. 1, thirty barrows (initial body weight [BW], 53.1±3.9 kg) were allotted to 1 of 5 diets formulated with 96.9% corn ground to 441, 543, 618, 659, and 768 ㎛, respectively. In Exp. 2, thirty-six barrows (initial BW, 54.7±3.6 kg) were allotted to 1 of 6 diets formulated by including 2% or 15% corn germ (CG 2 or CG 15), 1% or 6% corn oil (CO 1 or CO 6), 1% CO+2% corn germ meal (CO 1+CGM 2), or 6% CO+15% corn germ meal (CO 6+CGM 15), respectively. Results: The ATTD of gross energy (GE) and the digestible energy (DE) in diet and corn grain linearly decreased as the corn particle size increased (p<0.05) from 441 to 768 ㎛. Particle size had a quadratic effect (p<0.05) on the ATTD of neutral detergent fiber and acid detergent fiber in diets, and which firstly increased and then decreased as the corn particle size increased from 441 to 618 ㎛ and 618 to 768 ㎛, respectively. The ATTD of GE, ether extract (EE), and the DE in CO 1 diet and CO 6 diet was greater (p<0.05) than that in CG 2 diet and CG 15 diet, respectively. The ATTD of EE in CO 6 diet and CO 6+CGM 15 diet was greater (p<0.05) than that in CO 1 diet and CO 1+CGM 2 diet. Conclusion: Less than 618 ㎛ was recommended for corn particle size in growing pig's diet and extracted lipid had greater digestibility than the intact lipid in corn. Higher concentration of extracted CO had greater digestibility of EE compared with lower concentrations of CO diet.

• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1266-1274
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• 2006

A numerical study is performed to investigate the effect of inner surface roughness and micro-particles on adiabatic single phase frictional pressure drop in a perfect square micro channel. With the variation of particles sizes (0.1 to $1{\mu}m$) and occupied volume ratio (0.01 to 10%) by particles, the Eulerian multi-phase model is applied to a $100{\mu}m$ hydraulic diameter perfect square micro channel in laminar flow region. Frictional pressure loss is affected significantly by particle size than occupied volume ratio by particles. The particle properties like density and coefficient of restitution are investigated with various particle materials and the density of particle is found as an influential factor. Roughness effect on pressure drop in the micro channel is investigated with the consideration of roughness height, pitch, and distribution. Additionally, the combination effect by particles and surface roughness are simulated. The pressure loss in microchannel with 2.5% relative roughness surface can be increased more than 20% by the addition of $0.5{\mu}m$ diameter particles.

• Particle and aerosol research
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• v.9 no.2
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• pp.39-50
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• 2013

Real-time aerosol measuring instruments have been widely used for the measurement of atmospheric aerosol, diesel particulate matter, or material synthesis. A scanning mobility particle sizer (SMPS) measures the number size distribution of particles using electrical mobility detection technique. An aerodynamic particle sizer (APS) is used to determine the number concentration and the mean aerodynamic diameter of test particles. An electrical low-pressure impactor (ELPI) is a multi-stage impaction device to separate airborne particles into aerodynamic size classes using particle charging and electrical detection techniques. In this study, the performance of these instruments were evaluated to assess their ability to obtain mass concentrations from particle number concentration measurements made as a function of particle size. The effect of determination of particle density on the measurement of mass concentration was investigated for the three instruments.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.602-611
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• 2013

We have investigated the influence of system composition and preparation conditions on the particle size of vitamin E acetate (VE)-loaded nanoemulsions prepared by PIC(phase inversion composition) emulsification. This method relies on the formation of very fine oil droplets when water is added to oil/surfactant mixture. The oil-to-emulsion ratio content was kept constant (5 wt.%) while the surfactant-to-oil ratio (%SOR) was varied from 50 to 200 %. Oil phase composition (vitamin E to medium chain ester ratio, %VOR) had an effect on particle size, with the smallest droplets being formed below 60 % of VOR. Food-grade non-ionic surfactants (Tween 80 and Span 80) were used as an emulsifier. The effect of f on the droplet size distribution has been studied. In our system, the droplet volume fraction, given by the oil volume fraction plus the surfactant volume fraction, was varied from 0.1 to 0.3. The droplet diameter remains less than 350 nm when O/S is fixed at 1:1. The droplet size increases gradually as the increasing the volume fraction. Particle size could also be reduced by increasing the temperature when water was added to oil/surfactant mixture. By optimizing system composition and homogenization conditions we were able to form VE-loaded nanoemulsions with small mean droplet diameters (d < 50 nm). The PIC emulsification method therefore has great potential for forming nanoemulsion-based delivery systems for food, personal care, and pharmaceutical applications.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.578-592
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• 2021

This study performed to investigate the propagation characteristics of overpressure, impulse, vibration in underwater blasting. The difference between air blasting and underwater blasting is that noise and vibration propagate through water as a medium. In some cases, the noise and vibration propagates through various media (rock, water, air, etc.). In this study, the underwater blasting was simulated using AUTODYN, and the propagation characteristics of overpressure, impulse and vibration induced by blasting were analyzed. We mainly focused on the effect of mesh size on the overpressure, impulse and peak particle velocity from the underwater blasting simulation. The numerical results indicated that the overpressure and peak particle velocity tended to decrease as the mesh size increased, while the impulse increased with the mesh size. The results also indicated that the mesh dependence varied depending on the explosive charge and scaled distance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.9
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• pp.1139-1150
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• 1999

The evolution of silica aggregate particles in coflow diffusion flames has been studied experimentally using light scattering and thermophoretic sampling techniques. The measurements of scattering cross section from $90^{\circ}$ light scattering have been utilized to calculate the aggregate number density and volume fraction using with combination of measuring the particle size and morphology through the localized sampling and a TEM image analysis. Aggregate or particle number densities and volume fractions were calculated using Rayleigh-Debye-Gans and Mie theory for fractal aggregates and spherical particles, respectively. Of particular interests are the effects of flame temperature on the evolution of silica aggregate particles. As the flow rate of $H_2$ increases, the primary particle diameters of silica aggregates have been first decreased, but, further increase of $H_2$ flow rate causes the diameter of primary particles to increase and for sufficiently larger flow rates, the fractal aggregates finally become spherical particles. The variation of primary particle size along the upward jet centerline and the effect of burner configuration have also been studied.

• Tribology and Lubricants
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• v.15 no.3
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• pp.265-271
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• 1999

Wherever there are rotating equipment and contact between surface, there is wear and the generation of wear particles. The particles contained in the lubricating oil carry detailed and important information about the condition monitoring of the machine. This information may be deduced from particle shape, composition, size distribution, and concentration. Therefore, This paper was undertaken to Ferrography system of wear debris generated from lubricated moving machine surface. The lubricating wear test was performed under different experimental conditions using the Falex wear test of Pin and V-Block type by Ti(C, N) coated. It was shown from the test results that wear particle concentration (WPC) and wear severity Index( $I_{S}$), size distribution in normal and abnormal wear have come out all the higher value by increases sliding friction time. Wear shape is observed on the Ferrogram it was discovered a thin leaf wear debris as well as ball and plate type wear particles. This kind of large wear shape have an important effect not only metals damage, but also seizure phenomenon.