• Title, Summary, Keyword: particle size

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Comparative Analysis of Quality Properties by the Particle Size of Rice Flours according to Cultivars (품종별 쌀가루의 입자크기에 따른 품질특성 비교)

  • Shin, Dong-Sun;Lee, Eun-Chang;Choi, Ji-Youn;Oh, Sea-Kwan;Park, Hye-Young
    • The Korean Journal of Food And Nutrition
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    • v.30 no.4
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    • pp.635-643
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    • 2017
  • The properties of rice were studied, and 8 rice flour cultivars were used to study the effect of particle size on the physicochemical properties, color value, RVA viscosities, water absorption index (WAI), and water solubility index (WSI) of rice flours. The mean particle size by the 3 particle size classification of 150 mesh, 200 mesh, and 250 mesh was, $90.75{\mu}m$, $60.73{\mu}m$, $39.94{\mu}m$, respectively. Thai rice had the highest amylose content and Samkwang rice had the lowest amylose content. Protein content of rice flours prepared was decreased as the particle size of rice flour decreased. In terms of color values, the L-value and the a-value of rice flour were increased as the particle size of rice flours decreased, while the b-value was decreased as the particle size of rice flours decreased. Using a rapid visco analyzer (RVA), the initial pasting temperature of Thai rice cultivar was found to be the highest; the peak viscosities of Sunpum cultivar and Misomi cultivar, and Samkwang rice were higher than those of other rice flours. The water absorption index and water solubility index were increased as the particle size of rice flour decreased. In order to use processed rice flour for the development of processed foods, proper characteristics of the cultivars and particle size should be considered.

Performance Characteristics of In-Situ Particle Monitors at Sub-Atmospheric Pressure (감압상태에서의 In-Situ Particle Monitor의 성능특성)

  • Bae, Gwi-Nam
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.11
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    • pp.1564-1570
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    • 1998
  • In-situ particle monitors(ISPMs) are widely used for monitoring contaminant particles in vacuum-based semiconductor manufacturing equipment. In the present research, the performance of a Particle Measuring Systems(PMS) Vaculaz-2 ISPM at subatmospheric pressures has been studied. We created uniform upstream conditions of particle concentration and measured the detection efficiency, the lower detection limit, and the size response of the ISPM using uniform sized methylene blue aerosol particles. The effect of particle size, particle velocity, particle concentration, and system pressure on the detection efficiency was examined. Results show that the detection efficiency of the ISPM decreases with decreasing chamber pressure, and with increasing mass flow rate. The lower detection limit of the ISPM, determined at 50 % of the measured maximum detection efficiency, was found to be about $0.15{\sim}0.2{\mu}m$, which is similar to the minimum detectable size of $0.17{\mu}$ given by the manufacturer.

An Approach to the Influence of Particle Size Distribution of Leuco Vat Dye Converted by a Reducing Agent

  • Shim Woo-Sub;Lee Jung-Jin;Shamey Renzo
    • Fibers and Polymers
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    • v.7 no.2
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    • pp.164-168
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    • 2006
  • Three vat dyes have been applied to regular viscose rayon and their dyeing and wash fastness properties were evaluated. Particle size determination was undertaken to obtain information about the size of dye particles converted by a reducing agent, to see if dye particle size has an affect on dyeing properties of regular viscose rayon. It is observed that viscose rayon exhibits more dyeability with reducing agent concentrations between 5-7.5 g/l. Also, we found that the vat dyeing system is greatly affected by the particle size of the vat dye converted to leuco form by a reducing agent.

Impact of Biochar Particle Shape and Size on Saturated Hydraulic Properties of Soil

  • Lim, Tae-Jun;Spokas, Kurt
    • Korean Journal of Environmental Agriculture
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    • v.37 no.1
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    • pp.1-8
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    • 2018
  • BACKGROUND: Different physical and chemical properties of biochar, which is made out of a variety of biomass materials, can impact water movement through amended soil. The objective of this research was to develop a decision support tool evaluating the impact of the shape and the size distribution of biochar on soil saturated hydraulic conductivity ($K_{sat}$). METHODS AND RESULTS: Plastic beads of different size and morphology were compared with biochar to assess impacts on soil $K_{sat}$. Bead and biochar were added at the rate of 5% (v/w) to coarse sand. The particle size of bead and biochar had an effect on the $K_{sat}$, with larger and smaller particle sizes than the original sand grain (0.5 mm) decreasing the $K_{sat}$ value. The equivalent size bead or biochar to the sand grains had no impact on $K_{sat}$. The amendment shape also influenced soil hydraulic properties, but only when the particle size was between 3-6 mm. Intra-particle porosity had no significant influence on the $K_{sat}$ due to its small pore size and increased tortuosity compared to the inter-particle spaces (macro-porosity). CONCLUSION: The results supported the conclusion that both particle size and shape of the amended biochar impacted the $K_{sat}$ value.

Mapping Particle Size Distributions into Predictions of Properties for Powder Metal Compacts

  • German, Randall M.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.704-705
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    • 2006
  • Discrete element analysis is used to map various log-normal particle size distributions into measures of the in-sphere pore size distribution. Combinations evaluated range from monosized spheres to include bimodal mixtures and various log-normal distributions. The latter proves most useful in providing a mapping of one distribution into the other (knowing the particle size distribution we want to predict the pore size distribution). Such metrics show predictions where the presence of large pores is anticipated that need to be avoided to ensure high sintered properties.

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Effects of particle size on processing variables and green microstructure in gelcast alumina green bodies (겔-케스팅한 알루미나 성형체에서 출발입도가 공정변수 및 성형 미세구조에 미치는 영향)

  • Ha, Chang-Gi;Kim, Jae-Won;Jo, Chang-Yong;Baek, Un-Gyu;Jeong, Yeon-Gil
    • Korean Journal of Materials Research
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    • v.11 no.10
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    • pp.869-878
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    • 2001
  • Alumina $(Al_2O_3)$ green bodies were fabricated by gel-casting using three kinds of alumina with different particle size (mean particle size: 4.6 $\mu\textrm{m}$, 0.32 $\mu\textrm{m}$, 10nm). The effects of particle size on gel-casting process and green microstructure were investigated. The optimum dispersion conditions using ammonium salt (D-3019) as dispersant were 0.2 wt% (4.63 $\mu\textrm{m}$), 0.5 wt% (0.32 $\mu\textrm{m}$), and 5.0 wt% (10 nm), in high solid loading. The optimum solid loading of each starting material for gel-casting was obtained as 59 vol% (4.63 $\mu\textrm{m}$), 57 vol% (0.32 $\mu\textrm{m}$), 15 vol% (10 nm), depending on particle size, indicating that nano-size particle (10 nm) represent lower solid loading as high specific surface area than those of other two starting materials. The drying at ambient conditions (humidity; $\thickapprox$90%) was performed more than 48hrs to enable ejection of the part from the mold and then at $120^{\circ}C$ for 2hrs in an air oven, showing no crack and flaw in the dried green bodies. The pore size and distribution of the gelcast green bodies showed the significant decrease with decreasing particle size. Green microstructure was dependent on the pore size and distribution due to the particle size, and on the deairing step. The green density maximum obtained was 58.9% (4.63 $\mu\textrm{m}$), 60% (0.32 $\mu\textrm{m}$), 47% (10 nm) theoretical density (TD), and the deairing step applied before gel-casting did not affect green density.

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Higher levels of serum triglyceride and dietary carbohydrate intake are associated with smaller LDL particle size in healthy Korean women

  • Kim, Oh-Yoen;Chung, Hye-Kyung;Shin, Min-Jeong
    • Nutrition Research and Practice
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    • v.6 no.2
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    • pp.120-125
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    • 2012
  • The aim of this study was to investigate the influencing factors that characterize low density lipoprotein (LDL) phenotype and the levels of LDL particle size in healthy Korean women. In 57 healthy Korean women (mean age, $57.4{\pm}13.1$ yrs), anthropometric and biochemical parameters such as lipid profiles and LDL particle size were measured. Dietary intake was estimated by a developed semi-quantitative food frequency questionnaire. The study subjects were divided into two groups: LDL phenotype A (mean size: $269.7{\AA}$, n = 44) and LDL phenotype B (mean size: $248.2{\AA}$, n = 13). Basic characteristics were not significantly different between the two groups. The phenotype B group had a higher body mass index, higher serum levels of triglyceride, total-cholesterol, LDL-cholesterol, apolipoprotein (apo)B, and apoCIII but lower levels of high density lipoprotein (HDL)-cholesterol and LDL particle size than those of the phenotype A group. LDL particle size was negatively correlated with serum levels of triglyceride (r = -0.732, $P$ < 0.001), total-cholesterol, apoB, and apoCIII, as well as carbohydrate intake (%En) and positively correlated with serum levels of HDL-cholesterol and ApoA1 and fat intake (%En). A stepwise multiple linear regression analysis revealed that carbohydrate intake (%En) and serum triglyceride levels were the primary factors influencing LDL particle size ($P$ < 0.001, $R^2$ = 0.577). This result confirmed that LDL particle size was closely correlated with circulating triglycerides and demonstrated that particle size is significantly associated with dietary carbohydrate in Korean women.

Impacts of Limestone Multi-particle Size on Production Performance, Egg Shell Quality, and Egg Quality in Laying Hens

  • Guo, X.Y.;Kim, I.H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.6
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    • pp.839-844
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    • 2012
  • This experiment was conducted to evaluate the effects of single or multi-particle size limestone on the egg shell quality, egg production, egg quality and feed intake in laying hens. A total of 280 laying hens (ISA brown) were used in this 10-wk trial. Laying hens were randomly assigned to 4 treatments with 14 replications per treatment and 5 adjacent cages as a replication (hens were caged individually). The experimental treatments were: i) L, basal diet+10% large particle limestone; ii) LS1, basal diet+8% large particle limestone+2% small particle limestone; iii) LS2, basal diet+6% large particle limestone+4% small particle limestone; iv) S, basal diet+10% small particle limestone. The egg production was unaffected by dietary treatments. The egg weight in S treatment was lighter than other treatments (p<0.05). The egg specific gravity in S treatment was lower than other treatments (p<0.05). The eggshell strength and eggshell thickness in S treatment were decreased when compared with other dietary treatments (p<0.05). The laying hens in LS1 and LS2 treatment had a higher average feed intake than the other two treatments (p<0.05). Collectively,the dietary multi-particle size limestone supplementation could be as efficient as large particle size limestone.

Prediction Model for the Microstructure and Properties in Weld Heat Affected Zone : IV. Critical Particle Size for the Particle Coarsening Kinetics in Weld HAZ of Ti Added Low Alloyed Seel (용접 열영향부 미세조직 및 재질 예측 모델링: IV. Ti-첨가 저합금강에서의 임계 석출물 크기의 영향을 고려한 용접 열영향부 석출물 조대화 예측 모델)

  • Moon, Joon-Oh;Kim, Sang-Hoon;Jeong, Hong-Chul;Lee, Jong-Bong;Lee, Chang-Hee
    • Journal of Welding and Joining
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    • v.25 no.2
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    • pp.62-69
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    • 2007
  • A kinetic model fur the particle coarsening behavior was developed. The proposed model considered the critical particle size which can be derived from Gibbs-Thomson equation unlike the conventional approach. In this study, the proposed particle coarsening model was applied to study the coarsening behavior of titanium nitride (TiN particle) in microalloyed steel weld HAZ. Particle size distributions and mean particle size by the proposed model were in agreement with the experimental results. Meanwhile, using additivity rule, the isothermal model was extended to predict particle coarsening behavior during continuous thermal cycle.

Investigation of the model scale and particle size effects on the point load index and tensile strength of concrete using particle flow code

  • Haeri, Hadi;Sarfarazi, Vahab;Zhu, Zheming;Hedayat, Ahmadreza;Marji, Mohammad Fatehi
    • Structural Engineering and Mechanics
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    • v.66 no.4
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    • pp.445-452
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    • 2018
  • In this paper the effects of particle size and model scale of concrete have been investigated on point load index, tensile strength, and the failure processes using a PFC2D numerical modeling study. Circular and semi-circular specimens of concrete were numerically modeled using the same particle size, 0.27 mm, but with different model diameters of 75 mm, 54 mm, 25 mm, and 12.5 mm. In addition, circular and semi-circular models with the diameter of 27 mm and particle sizes of 0.27 mm, 0.47 mm, 0.67 mm, 0.87 mm, 1.07 mm, and 1.27 mm were simulated to determine whether they can match the experimental observations from point load and Brazilian tests. The numerical modeling results show that the failure patterns are influenced by the model scale and particle size, as expected. Both Is(50) and Brazilian tensile strength values increased as the model diameter and particle sizes increased. The ratio of Brazilian tensile strength to Is(50) showed a reduction as the particle size increased but did not change with the increase in the model scale.