Synthesis and Properties of Fe3O4 Ferrofluids with Narrow Particle Size Distribution

Fe3O4 ferrofluids with uniform magnetic particles were prepared via improved chemical coprecipation technique. A narrow distribution of 8.6-10.8 nm particle sizes was obtained from the magnetization curve using the free-form-model based on Bayesian inference theory. The mean particle diameter about 9.8 nm is consistent with the XRD and SEM results. The hydrodynamic properties of ferrofluids were investigated with different applied magnetic field and shear rate. The experimental results show that diluted ferrofluid and concentrated ferrofluid are Newtonian-fluid and Bingham-plastic fluid, respectively.

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Super Fine Powderization of Korean Ginseng Using Low Temperature Turbo Mill

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.445 ◽

2006 ◽

Vol 326-328 ◽

pp. 445-448 ◽

Cited By ~ 2

Author(s):

Beom Goo Lee ◽

Yeon Ho Jeong ◽

Dong Ha Cho ◽

Kang Yol Lee ◽

Wie Soo Kang

Keyword(s):

Particle Size ◽

Low Temperature ◽

Particle Size Distribution ◽

Size Distribution ◽

Particle Diameter ◽

Fine Powder ◽

Narrow Particle Size Distribution ◽

Volume Distribution ◽

The Mean ◽

Korean Ginseng

It is investigated whether ginseng can be milled into super fine powder below 50μm, changing the circumferential velocity of impeller of a turbo mill(100, 110 and 120m/s). The mean particle size is 113.3μm in control but is decreased abruptly into 11.9μm at 120m/s. The largest particle diameter at 97% of volume distribution is reduced into below 32μm at 120m/s from below 725μm at control. The particle size distribution between d(0.1) and d(0.9) is 334μm at control, but is decreased into less than 26μm in all conditions after milling. It shows that ginseng can be milled into super fine powder by the turbo mill, which has the narrow particle size distribution.

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Evaluating the Effects of Sediment Transport on Pipe Flow Resistance

Water ◽

10.3390/w13152091 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2091

Author(s):

Vito Ferro ◽

Alessio Nicosia

Keyword(s):

Velocity Profile ◽

Pipe Flow ◽

Power Distribution ◽

Flow Resistance ◽

Unit Length ◽

Particle Diameter ◽

Self Similarity ◽

Sediment Size ◽

The Mean ◽

The Relationship

In this paper, the applicability of a theoretical flow resistance law to sediment-laden flow in pipes is tested. At first, the incomplete self-similarity (ISS) theory is applied to deduce the velocity profile and the corresponding flow resistance law. Then the available database of measurements carried out by clear water and sediment-laden flows with sediments having a quasi-uniform sediment size and three different values of the mean particle diameter Dm (0.88 mm, 0.41 mm and 0.30 mm) are used to calibrate the parameter of the power-velocity profile). The fitting of the measured local velocity to the power distribution demonstrates that (i) for clear flow the exponent δ) can be estimated by the equation of Castaing et al. and (ii) for the sediment-laden flows δ is related to the diameter Dm. A relationship for estimating the parameter Гv obtained by the power-velocity profile) and that Гf of the flow resistance law) is theoretically deduced. The relationship between the parameter Гv, the head loss per unit length and the pipe flow Froude number is also obtained by the available sediment-laden pipe flow data. Finally, the procedure to estimate the Darcy–Weisbach friction factor is tested by the available measurements.

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Mechanical properties of microwave sintered Si3N4-based ceramics

Science of Sintering ◽

10.2298/sos0203223g ◽

2002 ◽

Vol 34 (3) ◽

pp. 223-229 ◽

Cited By ~ 8

Author(s):

O.I. Getman ◽

V.V. Holoptsev ◽

V.V. Panichkina ◽

I.V. Plotnikov ◽

V.K. Soolshenko

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Bending Strength ◽

Normal Pressure ◽

Ceramic Materials ◽

Particle Sizes ◽

Phase Measurements ◽

Ceramic Samples ◽

Mean Size ◽

The Mean

The mechanical properties and microstructure formation processes in Si3N4+3% AI2O3+5% Y2O3(Yb2O3) ceramic compacts sintered under microwave heating (MWH) and under traditional heating (TH) were investigated. The initial ceramic materials were powder blends of silicon nitride with oxides. The mean powder particle sizes were 0.5-1.0 mim. The content of alfa-phase in the Si3N4 powder was more than 95 %. The samples were sintered at 1800BC in nitrogen at normal pressure, the heating rate in all experiments was 60BC/min. The Vickers hardness (HV), fracture toughness (K1C) and bending strength (on) were determined. The microstructures of fracture surfaces of samples were studied by SEM. Quantitative microstructure analysis was carried out. It was shown that the values of HV and Kic of ceramic samples sintered under MWH at 1800BC rose steadily with the sintering time. This caused an increase in density, which reached maximum as fast as after 30 min of the MWH sintering; the mass loss at that time amounted to 3-4 %. The porosity of sintered samples with an addition of yttria was less than 1 %, that of ytterbia was greater, 2.4 %. For similar values of relative density, the hardness and fracture toughness of ceramic samples produced under MWH were higher as compared with those of samples sintered under TH. The microstructure of samples had the form of elongated grains in a matrix of polyhedral grains of the beta-Si3N4 phase. Measurements showed the mean size of grains in samples produced by MWH to be greater that in samples produced by TH. A larger number of elongated grains were formed. It was concluded that for sintering under MWH of Si3N4-based ceramics the growth of elongated beta-Si3N4 grains and formation of a "reinforced" microstructure were promoted and thereby improved the mechanical properties of such ceramics.

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Comparisons of formic acid oxidation at supported Pt catalyst and at low-index Pt single crystal electrodes in sulfuric acid solution

Journal of the Serbian Chemical Society ◽

10.2298/jsc0311849t ◽

2003 ◽

Vol 68 (11) ◽

pp. 849-857 ◽

Cited By ~ 20

Author(s):

Amalija Tripkovic ◽

Ksenija Popovic ◽

Jelena Lovic

Keyword(s):

Sulfuric Acid ◽

Formic Acid ◽

Single Crystal ◽

Particle Diameter ◽

Supported Catalyst ◽

Pt Catalyst ◽

Acid Oxidation ◽

Potential Region ◽

The Mean ◽

Supported Pt Catalyst

The oxidation of formic acid was studied at supported Pt catalyst (47.5 wt%. Pt) and a low-index single crystal electrodes in sulfuric acid. The supported Pt catalyst was characterized by the TEM and HRTEM techniques. The mean Pt particle diameter, calculated from electrochemical measurements fits well with Pt particle size distribution determined by HRTEM. For the mean particle diameter the surface averaged distribution of low-index single crystal facets was established. Comparison of the activities obtained at Pt supported catalyst and low-index Pt single crystal electrodes revealed that Pt(111) plane is the most active in the potential region relevant for fuel cell applications.

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MINERAL ABUNDANCE AND PARTICLE SIZE DISTRIBUTION DERIVED FROM IN-SITU SPECTRA MEASUREMENTS OF YUTU ROVER OF CHANG’E-3

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-3-w1-85-2017 ◽

2017 ◽

Vol XLII-3/W1 ◽

pp. 85-89

Author(s):

H. Lin ◽

X. Zhang ◽

Y. Yang ◽

X. Wu ◽

D. Guo

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Landing Site ◽

Radiative Transfer Model ◽

Transfer Model ◽

Particle Sizes ◽

The Mean ◽

The Difference ◽

Yutu Rover

From geologic perspective, understanding the types, abundance, and size distributions of minerals allows us to address what geologic processes have been active on the lunar and planetary surface. The imaging spectrometer which was carried by the Yutu Rover of Chinese Chang’E-3 mission collected the reflectance at four different sites at the height of ~&thinsp;1&thinsp;m, providing a new insight to understand the lunar surface. The mineral composition and Particle Size Distribution (PSD) of these four sites were derived in this study using a Radiative Transfer Model (RTM) and Sparse Unmixing (SU) algorithm. The endmembers used were clinopyroxene, orthopyroxene, olivine, plagioclase and agglutinate collected from the lunar sample spectral dataset in RELAB. The results show that the agglutinate, clinopyroxene and olivine are the dominant minerals around the landing site. In location Node E, the abundance of agglutinate can reach up to 70&thinsp;%, and the abundances of clinopyroxene and olivine are around 10&thinsp;%. The mean particle sizes and the deviations of these endmembers were retrieved. PSDs of all these endmembers are close to normal distribution, and differences exist in the mean particle sizes, indicating the difference of space weathering rate of these endmembers.

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Peristaltic transport of Bingham plastic fluid considering magnetic field, Soret and Dufour effects

Results in Physics ◽

10.1016/j.rinp.2017.06.009 ◽

2017 ◽

Vol 7 ◽

pp. 2000-2011 ◽

Cited By ~ 12

Author(s):

T. Hayat ◽

S. Farooq ◽

M. Mustafa ◽

B. Ahmad

Keyword(s):

Magnetic Field ◽

Peristaltic Transport ◽

Soret And Dufour Effects ◽

Bingham Plastic ◽

Plastic Fluid

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How Recyclability can Reduce Induction Period of Gold Nanocatalysts

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.57.1 ◽

2019 ◽

Vol 57 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Sedigheh Ghadamgahi

Keyword(s):

Catalytic Activity ◽

Reaction Time ◽

Gold Particle ◽

Particle Diameter ◽

Gold Catalysts ◽

Gold Particles ◽

Transmission Electron ◽

The Mean ◽

Full Conversion ◽

Catalytic Test

The effect of recyclability on the catalytic activity of supported Au101(PPh3)21Cl5 nanoparticles (1.0 wt% Au101/AC) was investigated for benzyl alcohol oxidation under mild conditions. The influence of recyclability on the catalytic activity of activated Au101/AC nanocatalysts was studied trough a comparison of gold particle diameter and also catalysts conversion between the fresh (as synthesized) and recycled gold catalysts. The monitoring of gold particle diameters by transmission electron microscopy (TEM) showed that the gold particles size gradually increased during the catalytic reaction. The mean diameter of the fresh gold catalysts increased from approximately 3 to 3.2, 5.1 and 5.3 nm after 1, 2 and 3 h reaction time, respectively. Whereas the average gold particle diameter of the recycled samples were slightly enlarged from approximately 5.3 (the sample recycled after 3 h of the first catalytic test) to 5.7, 5.9 and 6.2 nm with durations of 1, 2 and 3 h reaction time, respectively. Therefore, larger gold particles gradually formed for fresh and also recycled gold catalysts during reaction tests. Meanwhile, the catalytic activity of activated 1.0 wt% Au101/AC catalysts jumped to full conversion when the recycled gold catalysts were utilized due to removing ligand stabilizer from gold particles and so bigger particles had formed.

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Effect of a rotating cylinder on the flow of a Bingham plastic fluid in T-junction: Momentum and heat transfer characteristics

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2019.118506 ◽

2019 ◽

Vol 143 ◽

pp. 118506

Author(s):

Anamika Maurya ◽

Naveen Tiwari ◽

R.P. Chhabra

Keyword(s):

Heat Transfer ◽

Rotating Cylinder ◽

Heat Transfer Characteristics ◽

Bingham Plastic ◽

Transfer Characteristics ◽

Plastic Fluid ◽

Momentum And Heat Transfer

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Modeling reactive transport of polydisperse nanoparticles: assessment of the representative particle approach

Environmental Science Nano ◽

10.1039/c8en00666k ◽

2018 ◽

Vol 5 (10) ◽

pp. 2293-2303 ◽

Cited By ~ 2

Author(s):

Amir Taghavy ◽

Linda M. Abriola

Keyword(s):

Reactive Transport ◽

Particle Diameter ◽

Particle Sizes ◽

Ensemble Averaging ◽

Particle Approach

Our goal was to characterize the uncertainty in the estimates of the mobility and reactivity of polydisperse nanocolloids introduced into computations when a distribution of particle sizes is replaced with a representative particle diameter through ensemble averaging.

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