• Title/Summary/Keyword: Particle sire

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Effect of Cleaning Pad on Particle Contamination in Removable Media Disk Drive (이동식 디스크 드라이브의 입자 오염에 대한 클리닝 패드의 효과)

  • 유신성;이정규;김대은
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.4
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    • pp.183-188
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    • 2003
  • Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, the effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the Head Disk Interface (HDI) using a particle injection system. It was round that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except fer the particles of specific size and property. As a means to remove the particles of specific sire. the concept of using a stepped taper at the leading edge of the slider is proposed.

A Study on Recycling Technology of Waste Tire Powder by Particle Size Distribution Analysis (입도분포해석에 의한 폐타이어 분말의 재활용 연구)

  • Hwang, Sung-Hyuk;Jung, Jae-Hum;Pack, So-Yoon;Kim, Jin-Kuk
    • Elastomers and Composites
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    • v.38 no.2
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    • pp.128-138
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    • 2003
  • It goes to be serious with environmental pollution because of great number of waste tires scrapped each you. That is why there are lots of studies for efficient recycle. We tried to reduce particle size of the waste tire powder using a new technology of self-designed grinding machine (SDGM) and ultrasonic treatment. The purpose of this study is to improve the physical properties of reduced waste tire powder. We investigated the fine powder by particle size distribution(PSD) analysis. And also we examined the physical and mechanical properties and cross-link density at various particle sire. Also we carried out morphological studies after making the products by SEM.

Synthesis of FAU(Faujasite)-type Zeolite with Variation of Synthesis Condition (합성조건의 변화에 따른 FAU(Faujasite)형 제올라이트의 합성)

  • 임형미;김봉영;남중희;안병길;오성근;정상진
    • Journal of the Korean Ceramic Society
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    • v.40 no.2
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    • pp.132-138
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    • 2003
  • The effect of synthesis condition, type of starting materials, mole ratio, mixing. aging, and crystallization temperature and time, on the size of FAU-type zeolite has been studied. Different mixing route may lead to the different phase of zeolite even with the same starting materials. In general, the size of particles is smaller after aging, especially at lower aging temperature. Two step mixture gel preparation method resulted to not only the reduction of crystallization time but also that of particle size, but without the aging of two mixture gels before the preparation of the overall gel in the second step, only the crystallization time was reduced, not the particle size. The FAU-type zeolite with average particle size 0.4$\mu$m and BET surface area 838 $m^2$/g was obtained from starting materials of liquid sodium silicate, sodium aluminate, and sodium hydroxide with two step preparation of mixture gel, aging of the mixture gels in two steps, which effectively reduced the crystallization time and particle size.

The Influence of Grinding Time & Binder on the Particle Size Distribution of the Pearl Pigments (펄 안료의 입도분포에 미치는 분쇄시간 및 바인더의 영향)

  • So Tae-Sup;Go Du-Jin;Ro Hee-Su;Kim Sang-Bum;Kim Tae-Won;Kim Joong-Hoi
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.30 no.4 s.48
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    • pp.543-548
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    • 2004
  • For pearl pigments used for splendor or gloss effect of make-up products, especiallv point make-up products like eye-shadow and blusher, we studied the variation of particle size distribution by the grinding time and by the binder used as a binding agent. In this study. high speed mixer was used and the particle sire distribution was measured by using the light scattering method. In case of pearl pigments, its median diameter of $5{\;}{\mu}m$, the particle size was reduced to 4.6 um when it was ground for 120 s. When it was applied for the pearl pigment of $45{\;}{\mu}m$, the particle size was reduced to $27{\;}{\mu}m$. We confirmed that the latter was reduced more largely and the original gloss was reduced too. For the binder, we studied the correlation between particle size of raw material and grinding time. We also investigated the effects of the binder contents on the variation of particle size distribution of products by aggregation of particles.

$\beta$-glucan Contents and Their Characteristics of Winter Cereals According to Particle Sizes and Milling Recoveries

  • Kim, Sun-Lim;Park, Chul-Ho;Yu, Chang-Yeon;Hwang, Jong-Jin
    • Plant Resources
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    • v.4 no.3
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    • pp.140-146
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    • 2001
  • This study was conducted to investigate the $\beta$-glucan contents and their characteristics of winter cereals according to particle sizes and milling recoveries. Sieved fractions differed in their average contents of $\beta$-glucans, and the coarse fraction had higher contents of $\beta$-glucan than finely milled fractions. In all winter cereals, the $\beta$-glucan contents of raw flours were higher than those of their brans, and the highest $\beta$-glucan contents of every cereals were observed at 100 mesh > or 100-140 mesh fractions except the Chalssalbori fractions which showed the higest $\beta$-glucan contents (12.9%) at 140-200 mesh fraction. As compared with the $\beta$-glucan content of Chalbori among the various milling recoveries, the $\beta$-glucan was distributed more evenly throughout the endosperm but $\beta$-glucan content in bran of Chalbori was only 1.5%. However, $\beta$-glucan content of Chalssalbori (hull-less waxy barley) was the highest in the subaleurone region (8.2%) and declined slightly toward inner layers of grain. This results suggest that $\beta$-glucan distribution between high (Chalbori) and low $\beta$-glucan barley (Chalssalbori) may explain the difference in milling performance of barley. On the other hand, $\beta$-glucan contents of two rye varieties (Chilbohomil, Chunchoohomil) were lower than those of two waxy barley varieties, and the higest $\beta$-glucan contents were observed at the 60% milling recoveries. In all winter cereals, the L-values (lightness) of raw flours were higher than those of brans. And the L-values of barley varieties were higher than those of oat and rye varieties. As the particle sizes and milling recovery ratios were decreased, the L-value were increased. The a-values (redness) in brans of every winter cereals were higher than those of every particle size flours and every milling ratio fractions, and this tendency was observed in the b-values (yellowness) of every particle size of cereal flours. The L and b-value of barley, the b-value of oat, and L, a, b-value of rye have the significant relationship with the $\beta$-glucan contents, respectively. This results represent the fact that $\beta$-glucans affected the color of the flours and pounded grains of winter cereals.

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Water Quality and Particle Size Distributions of Road Runoff in Storm Event (강우시 도로유출수 수질특성 및 입경분포)

  • Lee, Jun-Ho;Cho, Yong-Jin;Bang, Ki-Woong
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.7
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    • pp.777-784
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    • 2005
  • The first flush phenomenon is defined as the initial period of road runoff during which the concentration of pollutants was significantly high. Road runoff contains significant loads of micro-particles, heavy metals and organic constituents. There were two major objectives of this study. The first objective was to characterize the road runoff. The second objective was to measure and evaluate particle sire distribution of the road runoff, Stormwater runoff was monitored on two sites of four lane road areas along with traffic volume. A total six storm events were monitored to characterize the road runoff. The quantity of road runoff and quality constituents, including chemical oxygen demand ($COD_{Cr}$), suspended solids(SS), total Kjeldahl nitrogen (TKN), ortho-phosphorus ($PO_4-P$), total phosphorus(TP), heavy metals and particle size distribution were analyzed. The results indicate that the concentration of SS, $COD_{Cr}$, TKN and TP ranges were $45{\sim}2,396\;mg/L$, $40{\sim}931\;mg/L$, $0.1{\sim}19.6\;mg/L$, and $0.2{\sim}25.1\;mg/L$, respectively. The results of the regression analysis between SS and the others constituents shows that $COD_{Cr}$, TP, Cu, Pb were highly correlated. And the results showed that the mean range of particle size and uniformity coefficient for road runoff were $6.7{\sim}23.4{\mu}$ and $6.4{\sim}10.2$, respectively.

The Friction and Wear of Boundary Lubricated Sliding Surfaces Using Three Different Surface Profile Spacing (경계윤활에서 표면의 스페이싱에 따른 마찰 및 마멸 특성)

  • 오세두;이영제
    • Tribology and Lubricants
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    • v.17 no.5
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    • pp.399-405
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    • 2001
  • In this paper the ball-on-disk type sliding tests with boundary lubricated steels were carried out to verify the relation between surface profiles and wear as well as scuffing. Three kinds of surface roughness and asperity radius were produced on AISI 1045 steels using the different processes of grinding and polishing. Frictional forces and time to scuffing were measured. Also, the shape and amount of wear particles were analyzed to compare with original profiles. From the tests, it was confirmed that the size of wear particles are very related to original surface profile. The time to failures and wear amounts were sensitive to the surface spacing. The large surface spacing shows much longer sliding life and smaller wear amount than the others. Time to scuffing was increased with increasing surface profile spacing. The sire of wear particles was increased and the amount was decreased with increasing surface profile spacing. Wear volume and wear rate K were decreased with increasing surface profile spacing. And after sliding tests, surface cracks of inner parts of the wear track occurred scuffing were observed and compared the differences about each specimen having the different surface profile spacing.

Adsorption of Toluidine Blue O onto Chitosan (키토산의 색소 Toluidine Blue O에 대한 흡착 특성)

  • Cho, Yoo-Young;Kim, Kwang-Yoon;Bom, Hee-Seung;Oh, Chang-Seok;Lee, Hyun-Chul;Park, Ro-Dong
    • Applied Biological Chemistry
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    • v.38 no.5
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    • pp.447-451
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    • 1995
  • Chitosan, a deacetylated polymer of chitin, was applied and characterized as an adsorbent for a dye Toluidine Blue O. The adsorption of Toluidine Blue O by chitosan was affected by the particle sire and mass of chitosan, initial dye concentration, reaction time, and solution pH. More dye was adsorbed the smaller the chitosan particles. When initial ratio of dye to chitosan was over 1 : 500, the adsorption of dye was rapidly declined. Adsorption rate of dye to chitosan showed 2 phases, rapidly occurred one at the beginning within 3 min and thereafter very slowly occurred one. The amount of dye adsorbed was increased with increase in pH.

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Luminescence Property of SrAl2O4:Eu2+ Powder Prepared by the Polymerized Complex Method (착체중합법으로 합성한 SrAl2O4:Eu2+ 분말의 형광특성)

  • 김선혜;심광보;강은태;정덕수;김창삼
    • Journal of the Korean Ceramic Society
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    • v.39 no.1
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    • pp.33-37
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    • 2002
  • The phosphorescence powder, $SrA1_2O_4:Eu^{2+}$, synthesized by a Polymerized Complex Method(PCM), has been compared with that by a Solid-State Reaction(SSR), and their luminescence characteristics have been studied. The PCM powders were synthesized at $900^{\circ}C$ and the SSR powders at $1200^{\circ}C$. The size of PCM powders was about $0.1{\mu}m$ and one tenth of that of the SSR powders, which was due to the lower synthesized temperature. On the other hand, residual carbon in the PCM powders decreased with an increase in the crystallinity of host lattice, which was responsible for the non-white color of the powders. Both powders showed the maximum luminescence peaks around 520nm in the wave length at room temperature. However, the peak position for the PCM powders was shifted to a slightly lower wavelength and the value of half-width of the peak was broad comparing to that of the SSR powders, and the peak intensity decreased significantly. Such a change in the luminescence characteristics was due to the large difference in size for two types of powders and partly the residual carbon in the PCM powders.

The Estimation of the Loss Possibility of Zeolite in Sandy Soil (사질토양(砂質土壤)에서의 Zeolite 유실(流失) 가능성(可能性)의 추정(推定))

  • Kang, Shin-Jyung;Choi, Jyung
    • Applied Biological Chemistry
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    • v.29 no.3
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    • pp.311-317
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    • 1986
  • This experiment was conducted to find out the minimum size of pores through that Zeolite particles moved vertically out with percolated solution in the sand column and to estimate whether they were lost through the pores in the field sandy soil. The results were as follows. 1. The amount of Zeolite loss through sand columns was increased in the order of the columns filled with $2{\sim}1>1{\sim}0.5>0.5>0.25mm$ sand particles. 2. The Zeolite particles lost through columns filled with $1{\sim}0.5$ and $0.5{\sim}0.25mm$ sand were clay fraction. 3. The pore sire that clay fraction of Zeolite mineral could migrate through was determined to be above $150{\mu}m$ and Jangchon subsoil was presumed to have possibility of Zeolite loss in consideration of its pore size distribution. 4. The suitable particle size of Zeolite for application in sandy soil was presumed to be above $2{\mu}m$.

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