• Title, Summary, Keyword: particle size

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The effect of process parameters on copper powder particle size and shape produced by electrolysis method

  • Boz, Mustafa;Hasheminiasari, Masood
    • Steel and Composite Structures
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    • v.15 no.2
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    • pp.151-162
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    • 2013
  • In this study, an electrolyzing device for the production of metal powders was designed and fabricated. The production of copper powders was performed using a variety of current densities, anode-cathode distances and power removal times. The effect of these parameters on powder particle size and shape was determined. Particle size was measured using a laser diffraction unit while the powder shape was determined by SEM. Experimental results show that an increase in current density leads to a decrease in powder particle size. In addition particle shape changed from globular dendritic to acicular dendritic with increasing the current density. Distance between the cathode and anode also showed a similar influence on powder particle size and shape. An increase in time of powder removal led to an increase in powder particle size, as the shape changed from acicular dendritic to globular dendritic.

Analysis model for the pneumatic solid processing system in non-uniform particle size condition (불균일 입도를 가지는 기류식 고체 처리 시스템을 위한 해석모델)

  • Choi, Donghwan;Choi, Sangmin
    • 한국연소학회:학술대회논문집
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    • pp.229-231
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    • 2015
  • In pneumatic reactor, hydrodynamic relation between gas and solid is important and particle size has a significant effect on this relation. In this reason, we analyzed drying and calcine process with a corrected model by considering the effect of the particle size distribution(PSD) with different seven particle groups by particle size.

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Fabrication of Nano-Sized Ni-ferrite Powder from Waste Solution Produced by Shadow Mask Processing (새도우마스크 제조공정 중 발생되는 폐액으로부터 니켈 페라이트 나노 분말 제조)

  • 유재근;서상기
    • Journal of Korean Powder Metallurgy Institute
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    • v.10 no.4
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    • pp.262-269
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    • 2003
  • Nano-sized Ni-ferrite powder was fabricated by spray pyrolysis process using the waste solution resulting from shadow mask processing. The average particle size of the powder was below 100 nm. The effects of the concentration of raw material solution, the nozzle tip size and air pressure on the properties of powder were studied. As the concentration increased, the average particle size of the powder gradually increased and its specific surface area decreased, but size distribution was much wider and the fraction of the Ni-ferrite phase greatly increased as the concentration increasing. As the nozzle tip size increased from 1 mm to 2 mm, the average particle size of the powder decreased. In case of 3 mm nozzle tip size, the average particle size of the powder increased slightly. On the other hand, in case of 5 mm nozzle tip size, average particle size of the powder decreased. Size distribution of the powder was unhomogeneous, and the fraction of the Ni-ferrite phase decreased as the nozzle tip size increasing. As air pressure increased up to 1 kg/$cm^2$, the average particle size of the powder decreased slightly, on the other hand, the fraction of the Ni-ferrite phase was almost constant. In case of 3kg/$cm^2$ air pressure, average particle size of the powder and the fraction of the Ni-ferrite phase remarkably decreased, but size distribution was narrow.

Effect of Sugar Particle Size and Level on Cookie Spread (설탕의 粒子 크기와 使用量이 쿠키의 展性이 미치는 影響)

  • Koh, Won-Bang;Noh, Wan-Seob
    • Journal of the East Asian Society of Dietary Life
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    • v.7 no.2
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    • pp.159-165
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    • 1997
  • The primary objective of this study was to learn the effect of various sugar particle size and level on cookie spread, The effect of sugar particle size and level on sugarsnap cookie spread was studied. Three different particle sized sugars; powered sugar, granulated sugar and sanding sugar, were used for the cookie test baking with five different sugar levels; 30, 45, 60, 75 and 90% based on the weight of flour. In mixing process, 5 minutes of creaming time was used for cream making and then the specific gravity of cream was measured on the basis of each different sugar particle size and level. In the result, the specific gravity of cream was influenced by sugar particle size and sugar level. However, the specific gravity of cream had no influence on cookie dough specific gravity. Cookie spread was influenced by sugar particle size and sugar level. Greater cookie spread was obtained by decreasing sugar particle size and increasing sugar level resulted in increased spread. Therefore, selection of suitable sugar particle size and its use level can be factors in controlling spread and imparting desired packaging characteristics.

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Initial Particle Size Effects on Sintering and Dielectric Properties of $Pb>(Fe_1/2Nb_1/2)O_3$ (초기입자크기가 $Pb>(Fe_1/2Nb_1/2)O_3$의 소결 및 유전성에 미치는 영향)

  • 박경봉;김태희;윤기현
    • Journal of the Korean Ceramic Society
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    • v.29 no.9
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    • pp.711-718
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    • 1992
  • Pb(Fe1/2Nb1/2)O3 was prepared by the molten salt synthesis method using an equimolar mixture of NaCl-KCl. Initial particle size could be controlled by varying the weight ratio of the NaCl-KCl to raw materials from 0.1 to 1.0, and the initial particle size effects on the sintering and dielectric properties of Pb(Fe1/2Nb1/2)O3 were investigated at the sintering temperature range from 90$0^{\circ}C$ to 105$0^{\circ}C$. As the weight ratio of salt increased, the average particle size decreased and the particle size distributions tended to narrow. As the initial particle size decreased, the linear shrinkage and density increased due to the promotion of densification. Dielectric constant increased with decreasing the initial particle size resulting from the increase of density and grain size.

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Effects of Contamination Source and Particle Size on Arsenic Speciation and Bioaccessibility in Soils (오염원에 따른 토양 입경 별 비소의 오염특성 및 생물학적 접근성 평가)

  • Kwon, Ye-Seul;Kim, Eun Jung
    • Journal of Soil and Groundwater Environment
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    • v.22 no.5
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    • pp.89-97
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    • 2017
  • In this study, we evaluated effect of particle size on arsenic solid-state speciation and bioaccessibility in soils highly contaminated with arsenic from smelting and mining. Soils were partitioned into six particle size fractions ($2000-500{\mu}m$, $500-250{\mu}m$, $250-150{\mu}m$, $150-75{\mu}m$, $75-38{\mu}m$, <$38{\mu}m$), and arsenic solid-state speciation and bioaccessibility were characterized in each particle size fraction. Arsenic solid-state speciation was characterized via sequential extraction and XRD analysis, and arsenic bioaccessibility was evaluated by SBRC (Solubility Bioaccessibility Research Consortium) method. In smelter site soil, arsenic was mainly present as arsenic bound to amorphous iron oxides. Fine particle size fractions showed higher arsenic concentration, but lower arsenic bioaccessibility. On the other hand, arsenic in mine site soil showed highest concentration in largest particle size fraction ($2000-500{\mu}m$), while higher bioaccessibility was observed in smaller particle size fractions. Arsenic in mine site soil was mainly present as arsenolite ($As_2O_3$) phase, which seemed to affect the distribution of arsenic and arsenic bioaccessibility in different particle size fractions of the mine soil.

Fabrication of the Nano-Sized Nickel Oxide Powder by Spray Pyrolysis Process

  • Yu, Jae-Keun;NamGoong, Hyun;Kim, Dong-Hee
    • Korean Journal of Materials Research
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    • v.22 no.8
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    • pp.426-432
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    • 2012
  • This study involves using nickel chloride solution as a raw material to produce nano-sized nickel oxide powder with average particle size below 50 nm by the spray pyrolysis reaction. The influence of the inflow speed of raw material solution on the properties of the produced powder is examined. When the inflow speed of the raw material solution is at 2 ml/min., the average particle size of the powder is 15~25 nm and the particle size distribution is relatively uniform. When the inflow speed of the solution increases to 10 ml/min., the average particle size of the powder increases to about 25 nm and the particle size distribution becomes much more uneven. When the inflow speed of the solution increases to 20 ml/min., the average particle size of the powder increases in comparison to the case in which the inflow speed of the solution was 10 ml/min. However, the particle size distribution is very uneven, showing various particle size distributions ranging from 10 nm to 70 nm. When the inflow speed of solution increases to 50 ml/min., the average particle size of the powder decreases in comparison to the case in which the inflow speed was 20 ml/min., and the particle size distribution shows more evenness. As the inflow speed of the solution increases from 2 ml/min. to 20 ml/min., the XRD peak intensities gradually increase, while the specific surface area decreases. When the inflow speed of solution increases to 50 ml/min., the XRD peak intensities rather decrease, while the specific surface area increases.

Particle size distributions and concentrations above radiators in indoor environments: Exploratory results from Xi'an, China

  • Chen, Xi;Li, Angui
    • Environmental Engineering Research
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    • v.20 no.3
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    • pp.237-245
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    • 2015
  • Particulate matter in indoor environments has caused public concerns in recent years. The objective of this research is to explore the influence of radiators on particle size distributions and concentrations. The particle size distributions as well as concentrations above radiators and in the adjacent indoor air are monitored in forty-two indoor environments in Xi'an, China. The temperatures, relative humidity and air velocities are also measured. The particle size distributions above radiators at ten locations are analyzed. The results show that the functional difference of indoor environments has little impact on the particle size distributions above radiators. Then the effects of the environmental parameters (particle concentrations in the adjacent indoor air, temperatures, relative humidities and air velocities) on particle concentrations above radiators are assessed by applying multiple linear regression analysis. Three multiple linear regression models are established to predict the concentrations of $PM_{10}$, $PM_{2.5}$ and $PM_1$ above radiators.

Experimental Study on the Effect of Particle Size Distribution of Soil on the Liquefaction Resistance Strength (입도분포가 액상화 저항강도에 미치는 영향에 관한 실험적 연구)

  • Seo Kyung-Bum;Choi Mun-Gyu;Kim Soo-Il;Park Inn-Joon
    • Journal of the Korean Geotechnical Society
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    • v.21 no.7
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    • pp.13-20
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    • 2005
  • For experimental study on the effect of particle size distribution on the liquefaction resistance strength, particle size distribution curves of the dredged soil were investigated. In this process, four mean particle sizes and three uniformity coefficients were defined representatively and twelve representative particle size distribution curves which have different mean particle size and uniformity coefficient, were defined and manufactured by using the real dredged river soil. Cyclic triaxial tests and resonant column tests were carried out to analyze the effect of mean particle size and uniformity coefficient on the liquefaction resistance strength and dynamic characteristics.

Influences of Particle Property and Its Size Impact Damage and Strength Degradation in Silicon Carbide Ceramics (탄화규소 세라믹의 충격손상 및 강도저하에 미치는 입자의 재질 및 크기의 영향)

  • 신형섭;전천일랑;서창민
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.10
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    • pp.1869-1876
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    • 1992
  • The effect of particle property on FOD(foreign object damage) and strength degradation in structural ceramics especially, silicon carbide was investigated by accelerating a spherical particle having different material and different size. The damage induced showed significant differences in their patterns with increase of impact velocity. Also percussion cone was formed at the back part of specimen when particle size became large and its impact velocity exceeded a critical value. The extent of ring cracks was linearly related to particle size, however the impact of steel particle produced larger ring cracks than that of SiC particle. Increasing impact velocity the residual strength showed different degradation behaviors according to particle and its size. In the region the impact site represents nearly elastic deformation behavior, the residual strength was dependent upon the depth of cone crack regardless of particle size. However in elastic- plastic deformation region, the radial cracks led to rapid drop in residual strength.