• Title/Summary/Keyword: Mixed Particle

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Enhanced Dispersion of Yttria Stabilized Zirconia by Mixed Dispersants Containing Carboxyl Group in Aqueous System (수성 현탁액에서 카르복실기를 포함하는 혼합 분산제에 의한 이트리아 안정화 지르코니아의 분산성 향상)

  • Kim, Soo-Hyun;Kang, Jong-Bong;Bae, Sung-Hwan
    • Korean Journal of Materials Research
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    • v.28 no.2
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    • pp.82-88
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    • 2018
  • Stable slurries of YSZ in aqueous suspension with added polymer dispersants, namely, poly-methacrylic acid ammonium salt (PMMA), poly-acrylic acid (PAA) and poly-acrylic-co-maleic acid (PAMA), were mixed with the monomolecular dispersants citric acid and oxalic acid. The dispersion properties of the suspension were investigated using PSA, viscosity, sedimentation, and FT-IR. The polymer dispersants and monomolecular dispersants were attached to the YSZ surface by the carboxylic group, as shown by the FTIR results. A stabilized aqueous suspension was obtained when the polymer dispersant and citric acid were mixed and compared to the use of citric acid alone as a dispersant agent. When the polymer dispersant and citric acid were mixed and milled through attrition milling, there was a smaller particle size compared to when the polymer dispersant alone was used as a dispersant agent. This study determined that the particle size of the mixed dispersant was affected by the properties of the monomolecular dispersant and that the stability of the suspension was affected by the polymer dispersant. However, when slurries of YSZ were mixed with oxalic acid, the particle bridging behavior was the result of the high degree of viscosity and the small sedimentation height.

Effect of Storage Temperature on the Dispersion Stability of O/W Nano-emulsions (O/W 나노에멀젼 분산안정성에 미치는 보관온도의 영향)

  • Lee, Ye-Eun;Yoo, In-Sang
    • KSBB Journal
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    • v.29 no.5
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    • pp.385-391
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    • 2014
  • In this study, the emulsion dispersion stability of optimizing storage temperature was investigated. The system was based on oil/water (O/W) emulsions. In order to evaluate the stability, mean diameter of droplet was measured as a function of temperature with various mixed hydrophilic lipophilic balance (HLB). In addition, the correlations between phase inversion temperature (PIT) and the optimum storage temperature were probed. In this system, majority of the smallest droplet was shown at temperature of $20^{\circ}C$ below PIT. Whether the temperature was increased or decreased from the optimum, size of the droplet increased. According to the mixed HLB, the particle size and optimum storage temperature were also affected. As the concentrations of surfactant were increased, the size of particle decreased with lower optimum temperature for storage. If the surfactant (4 wt%) were mixed with HLB, the optimum storage temperature was $21^{\circ}C$ for maintaining the size of smallest droplet at 108.3 nm in diameter. At above optimum condition, increased size of particle was observed approximately 4 % increases from 108.2 nm to 112.3 nm after 600 hours. The size of particle in emulsion was maintained stably without any considerable effect of Ostwald ripening phenomena at the optimum storage temperature with low polydispersity index.

An Experimental Study on the Performance Improvement of Mortar Using Crashed Fine Aggregate (부순모래를 대량 활용한 모르타르의 성능향상에 관한 실험적 연구)

  • Park Jong-Ho;Na Chul-Sung;Cho Bong-Suk;Choi Se-Jin;Lee Sung-Hyun;Kim Moo-Han
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.121-124
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    • 2005
  • As a countermeasure about that, in this situation that suggest utilizing mixed drush sand and particle washed sand, this study is reviewing and comparing, as a experimental and positive test, mixed both workability and engineering properties of mortar, The purpose of this study make a suggestion that is fundamental data for utilizing mixed crush sand and particle washed sand.

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Tensile Strength of Composites from Hanji(Korean paper) Sludge Mixed with Wood Fiber or Pariticle (한지 슬러시-목재 섬유 또는 목재 파티클 복합재의 인장강도)

  • 이필우;손정일;이영규
    • Journal of the Korea Furniture Society
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    • v.10 no.1
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    • pp.51-56
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    • 1999
  • This research was carried out to investigate the Hanji sludge(black color)-wood fiber and wood particle composited applied by waste sludges arising from the making process of Hanji (Korea paper). In experimental design, four levels of the mixed ratio of Hanji sludge to wood fiber or wood particle(10:90, 20:80, 30:70 and 40:60), three kinds of the resin(PMDI, urea and phenol resin)and three kinds of the specific gravity(0.6, 0.75 and 0.9) were designed to determine the tensile strength of Hanji sludge-wood fiber and wood particle composites. From the results and discussion, it may be concluded as follows: In Hanji sludge-wood fiber and wood particle composites, tensile strengths showed decreasing tendency absolutely by increasing Hanji sludge additive, but clearly increase with the increase of specific gravity. In Hanji sludge-wood fiber composites, there were no differences between PMDI and urea resin-bonded composites, but phenol resin-boned composites were made possibly until the addition of 30% Hanji sludge. On the other hand, Hnji sludge-wood particle composites(SpGr=0.6) have very low tensile strength values. But they were made favorably until the addition of 20% Hanji sludge in Hanji sludge-wood particle composites(SpGr=0.9).

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Effect of Rice Straw Steaming Time and Mixing Ratio between Acacia mangium Willd Wood and Steamed Rice Straw on the Properties of the Mixed Particleboard

  • Tran, Van Chu;Le, Xuan Phuong
    • Journal of Forest and Environmental Science
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    • v.31 no.2
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    • pp.119-125
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    • 2015
  • This study examined the effects of rice straw steaming time and mixing ratio between rice straw and wood particle on the properties of mixed particle board from Acacia mangium Willd wood and rice straw. Rice straw and Acacia mangium Willd wood were collected in Hanoi, Vietnam. The particle board was three-layer particle board with the structural ratio of 1:3:1. The thickness, density and board size of the particle board were 18 mm, $0.7g/cm^3$, and $800{\times}800{\times}18$ (mm, including trimming), respectively. A resin mixture between commercial Urea-formaldehyde (U-F) adhesive and methylene diphenyl isocyanate (MDI) adhesive was used with a dosage of 12% for the core layer and 14% for the surface layer. In this experimental design, the steaming time for rice straw was 15, 30, 45, 60, and 75 minutes at $100^{\circ}C$. The rice straw-wood mixing ratio was 10, 20, 30, 40, and 50%. The results showed that both mixing ratio and steaming time affect the properties of the particleboard, but the mixing ratio has a stronger impact. A higher mixing ratio and a longer steaming time resulted in a better quality of particleboard. The optimal steaming time for rice straw was 46.12 minutes with the straw-wood mixing ratio of 29.85% with the following characteristics of the particle board: the modulus of rupture (MOR) of 14.64 MPa, internal bond strength (IB) of 0.382 MPa, thickness swelling (TS) of 8.83%, and board density of $0.7-0.7g/cm^3$.

A Numerical Study on the Triboelectrostatic Separation of PVC Materials From Mixed Plastics for Waste Plastic Recycling

  • Ha, Man-Yeong;Jeon, Chung-Hwan;Park, Doo-Seong;Park, Hae-Jin
    • Journal of Mechanical Science and Technology
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    • v.17 no.10
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    • pp.1485-1495
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    • 2003
  • We investigate the triboelectrostatic separation of polyvinylchloride (PVC) from mixed plastics in the laboratory scale triboelectrostatic separation system. The flow and electric fields in the precipitator are obtained from the numerical solution of finite volume method. Using these flow and electric fields, we solved the particle motion equation considering the inertia, drag, gravity and electrostatic forces acted on the particles. The particle trajectories are obtained using a Lagrangian method as a function of different important variables such as Reynolds number, Stokes number, electrostatic force, electric charge and electric field distribution, inclined angle of plane electrodes, particle rebounding, particle charge decay rate after impact on the electrode surface, etc., in order to determine the optimal design conditions. The present predicted results for the cumulative yield represent well the experimental ones.

Evaluation of strength of waste material mixed concrete using digital image (디지털이미지를 이용한 폐기물 혼합 콘크리트의 강도 평가)

  • Yoon, Hyun-Suk;Lee, Ki-Ho;Park, Jun-Boum
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1390-1395
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    • 2005
  • To analyze the effects of oyster shell particles, inserted in the self-hardening matrix such as cement paste, on strength, homogenization analysis using micro structure was used to estimate and assess the apparent elastic modulus of oyster shell particle. DIB modeling technique was used to represent of the micro structure of oyster shell mixed concrete. The results showed that the apparent elastic modulus of LOS (large oyster shell particle) was changed with the amount of LOS inserted. In particular, when the amount of LOS was 200% of the weight of cement, the apparent elastic modulus of LOS tended to decrease rapidly. This could mean that the strength of oyster shell mixed concrete is much affected by LOS inserted material in mixed ratio of 200%.

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Quantitative Visualization of Mixed Convection in 3-D Rectangular Channels Using TLC Tracers (액정을 이용한 3차원 사각채널 내 혼합대류의 정량적 가시화)

  • Piao, Ri-Long;Kim, Jeong-Soo;Bae, Dae-Seok
    • Journal of Power System Engineering
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    • v.20 no.6
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    • pp.51-57
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    • 2016
  • Experiment is carried out to investigate the mixed convective flow in three-dimensional horizontal rectangular channels filled with high viscous fluid. The particle image velocimetry(PIV) with thermo-sensitive liquid crystal tracers is used for visualizing and analysis. Quantitative data of temperature and velocity are obtained by applying the color-image processing to a visualized image, and neural network is applied to the color-to-temperature calibration. In this study, the fluid used is silicon oil(Pr=909), the aspect ratio(channel width to heigh) is 4 and Reynolds number is $2{\times}10^{-2}$. From the present study, we can visualize the quantitative temperature and velocity of mixed convective flow in three-dimensional horizontal rectangular channels simultaneously.

Effects of Particle Size of Barley on Intestinal Morphology, Growth Performance and Nutrient Digestibility in Pigs

  • Morel, P.C.H.;Cottam, Y.H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.11
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    • pp.1738-1745
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    • 2007
  • A growth trial and a digestibility trial were conducted to examine the effect of feed particle size on the performance, nutrient digestibility, gastric ulceration and intestinal morphology in pigs fed barley-based diets. Barley was processed through a hammer mill to achieve four diets varying in particle size (average particle $size{\pm}standard $deviation): coarse ($1,100{\pm}2.19\;{\mu}m$), medium ($785{\pm}2.23\;{\mu}m$), fine ($434{\pm}1.70\;{\mu}m$) and mixed (1/3 of coarse, medium and fine) ($789{\pm}2.45\;{\mu}m$). Sixty-four entire male pigs were used in the growth trial and the diets were fed ad libitum between 31 kg and 87 kg live weight. Following slaughter, stomach and ileal tissues were scored for integrity (ulceration or damage) and histological measurements taken. Twenty-four entire male pigs were used in the digestibility trial, which involved total faecal collection. Over the entire growth phase, there were no differences (p>0.05) in average daily gain and feed conversion ratio between pigs fed diets of different particle size. Pigs fed the coarse and medium diets had lower (p<0.05) stomach ulceration scores (0.20 and 0.25, respectively, on a scale from 0 to 3) than those fed the mixed (0.69) or the fine diets (1.87). The stomachs of all animals fed the fine diet had lesions and stomach ulcerations were present only in this group. Pigs fed the fine diet had thicker (p<0.001) ileal epithelial cell layer with no differences (p>0.05) being observed for villous height or crypt depth. Faecal digestibility coefficients of neutral and acid detergent fibre were the highest (p<0.05) for the mixed diet, intermediate for the fine and coarse diets and the lowest for the medium diet. A similar numerical trend (p = 0.103) was observed for the apparent faecal energy digestibility coefficient. It is concluded that, with barley based diets, a variation in average particle size between $400{\mu}m$ and $1,100{\mu}m$ had no effect on pig performance but the fine dietary particle size affected the integrity of the stomach, as well as the structure of the small intestine, thus compromising overall gut health. Our data also demonstrate that changes in particle size distribution during the digestion process, rather than average particle size or particle size variation, are related to apparent faecal digestibility.

Evaluation of One-particle Stochastic Lagrangian Models in Horizontally - homogeneous Neutrally - stratified Atmospheric Surface Layer (이상적인 중립 대기경계층에서 라그랑지안 단일입자 모델의 평가)

  • 김석철
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.4
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    • pp.397-414
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    • 2003
  • The performance of one-particle stochastic Lagrangian models for passive tracer dispersion are evaluated against measurements in horizontally-homogeneous neutrally-stratified atmospheric surface layer. State-of-the-technology models as well as classical Langevin models, all in class of well mixed models are numerically implemented for inter-model comparison study. Model results (far-downstream asymptotic behavior and vertical profiles of the time averaged concentrations, concentration fluxes, and concentration fluctuations) are compared with the reported measurements. The results are: 1) the far-downstream asymptotic trends of all models except Reynolds model agree well with Garger and Zhukov's measurements. 2) profiles of the average concentrations and vertical concentration fluxes by all models except Reynolds model show good agreement with Raupach and Legg's experimental data. Reynolds model produces horizontal concentration flux profiles most close to measurements, yet all other models fail severely. 3) With temporally correlated emissions, one-particle models seems to simulate fairly the concentration fluctuations induced by plume meandering, when the statistical random noises are removed from the calculated concentration fluctuations. Analytical expression for the statistical random noise of one-particle model is presented. This study finds no indication that recent models of most delicate theoretical background are superior to the simple Langevin model in accuracy and numerical performance at well.