scholarly journals Dynamics of sheared droplets filled with non-Brownian particles

2020 ◽  
Vol 59 (12) ◽  
pp. 935-949
Author(s):  
Helene Van Ammel ◽  
Paula Moldenaers ◽  
Ruth Cardinaels
Keyword(s):  
Bulk Viscosity ◽  
Particle Concentration ◽  
Viscosity Ratio ◽  
Viscous Medium ◽  
Particle Sizes ◽  
Droplet Dynamics ◽  
Brownian Particles ◽  
Homogenous Medium ◽  
Single Droplets ◽  
Good Agreement

AbstractThe dynamics of single droplets containing non-Brownian particles are studied. The particle over droplet size ratio (r/R) is changed by using different particle sizes (r/R = 0.02–0.4). Additionally, the effect of particle concentration (5–20 vol%) is investigated. The dynamics of droplets with r/R = 0.02 show good agreement with the corresponding particle-free reference system which has a comparable viscosity ratio. Hence, this droplet phase can be considered as a homogenous medium characterized by its bulk viscosity which is governed by the particle concentration. However, droplets with r/R ≥ 0.1 show a more suppressed deformation and slower transient dynamics and, therefore, behave as a slightly more viscous medium than expected based on their bulk viscosity. These effects become more pronounced at higher particle concentrations and higher r/R. Moreover, local particle effects like asymmetric droplet shapes, oscillating droplet shapes, and tip streaming start to influence the droplet dynamics at particle concentrations around 15 vol%.

A comparative study of lead adsorption by activated Khaya Ivoresnsis and Pycanthus Angolensis sawdust

2016 ◽  
Vol 6 (4) ◽  
pp. 593-601
Author(s):  
Chidozie Charles Nnaji ◽  
Stephen Chinwike Emefu
Keyword(s):  
Experimental Data ◽  
Freundlich Isotherm ◽  
Intraparticle Diffusion ◽  
Bulk Liquid ◽  
Timber Species ◽  
Particle Sizes ◽  
Lead Adsorption ◽  
Intraparticle Diffusion Model ◽  
First Order Kinetics ◽  
Good Agreement

Experiments investigating lead adsorption by activated sawdust of different particle sizes of two timber species were conducted. The experimental data were fitted to isothermal and kinetic models. The optimum particle size was 0.85 mm for Khaya ivorensis and 1.18 mm for Pycanthus angolensis. The adsorption of lead by Khaya ivorensis and Pycanthus angolensis conformed to the Langmuir isotherm (0.83 ≤ R2 ≤ 0.96 and 0.86 ≤ R2 ≤ 0.98, respectively) and Freundlich isotherm (0.69 ≤ R2 ≤ 0.97 and 0.94 ≤ R2 ≤ 1.0, respectively). The adsorption process for the two species of timber was controlled by solute transport in the bulk liquid and intraparticle diffusion which was confirmed by good agreement of experimental data with pseudo-first-order kinetics (0.96 ≤ R2 ≤ 1.0 for Khaya ivorensis and 0.9 ≤ R2 ≤ 1.0 for Pycanthus angolensis) and the intraparticle diffusion model (0.9 ≤ R2 ≤ 0.99 for Khaya ivorensis and 0.84 ≤ R2 ≤ 0.97 for Pycanthus angolensis). A new kinetic model was developed with R2 of 0.93 ≤ R2 ≤ 0.99 for Khaya ivorensis and 0.88 ≤ R2 ≤ 1.0 for Pycanthus angolensis.

scholarly journals Theoretical and Experimental Evaluation of Particle size Effect of Iron , Cobalt ,and Nickel Powders Suspended in Al Dura oil on XRF Intensities

2007 ◽  
Vol 4 (3) ◽  
pp. 475-481
Author(s):  
Baghdad Science Journal
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Laser System ◽  
Particle Size Effect ◽  
Particle Sizes ◽  
Iron Cobalt ◽  
X Ray ◽  
Nickel Powders ◽  
Good Agreement ◽  
Cobalt And Nickel

Iron , Cobalt , and Nickel powders with different particle sizes were subjected to sieving and He-Ne laser system to determine the particle size . 1wt% from each powders was blended carefully with 99wt% from Iraqi oil . Microscopic examination were carried for all samples to reveal the particle size distribution . A Siemens type SRS sequential wavelength dispersive(WDS) X-ray spectrometer was used to analyze all samples , and the XRF intensity were determined experimentally and theoretically for all suspended samples , Good agreement between theoretical and experimental results were found .

Brownian-Motion-Based Convective-Conductive Model for the Effective Thermal Conductivity of Nanofluids

2005 ◽  
Vol 128 (6) ◽  
pp. 588-595 ◽  
Author(s):  
Ravi Prasher ◽  
Prajesh Bhattacharya ◽  
Patrick E. Phelan
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Particle Sizes ◽  
Brownian Movement ◽  
Liquid Temperature ◽  
Interfacial Resistance ◽  
Conduction Model ◽  
Order Of Magnitude ◽  
Base Liquid ◽  
Good Agreement

Here we show through an order-of-magnitude analysis that the enhancement in the effective thermal conductivity of nanofluids is due mainly to the localized convection caused by the Brownian movement of the nanoparticles. We also introduce a convective-conductive model which accurately captures the effects of particle size, choice of base liquid, thermal interfacial resistance between the particles and liquid, temperature, etc. This model is a combination of the Maxwell-Garnett (MG) conduction model and the convection caused by the Brownian movement of the nanoparticles, and reduces to the MG model for large particle sizes. The model is in good agreement with data on water, ethylene glycol, and oil-based nanofluids, and shows that the lighter the nanoparticles, the greater the convection effect in the liquid, regardless of the thermal conductivity of the nanoparticles.

Simfuel Leaching Studies in Granitic Groundwater Under Oxidizing Conditions

1995 ◽  
Vol 412 ◽  
Author(s):  
J. Garcia-Serrano ◽  
J. A. Serrano ◽  
P. P. Diaz-Arocas ◽  
J. Quiñones ◽  
J. L. R. Almazan
Keyword(s):  
Elemental Analysis ◽  
Particle Sizes ◽  
Leaching Tests ◽  
Minor Components ◽  
High Release ◽  
Synthetic Groundwater ◽  
Granitic Groundwater ◽  
Good Agreement

AbstractSimulated high-bumup nuclear fuel (SIMFUEL) has been leached in synthetic groundwater under oxic conditions. SIMFUEL pellets were ground and sieved to two particle sizes (50–100 and 100–315 μm). An extensive solid characterization of the fragments was carried out by various techniques. Elemental analysis has also been performed prior to the leaching tests.The release of U and the minor components (Mo, Ba and Sr) was monitored during the long term dissolution experiments (350 days). These minor components exhibit a trend similar to uranium, high release at the beginning followed by a plateau. The M/U calculated ratios show different behavior although after a period of time, depending on the particle sizes, constant ratios were observed.SIMHUEL powder was used in order to simulate the physical effect of bum-up on the fuel structure. This fact seems to play an important role on the uranium release. A comparison with the results given in the literature for SIMFUEL pellet leaching tests shows good agreement with the values reported.

scholarly journals Light scattering at small angles by atmospheric irregular particles: modelling and laboratory measurements

2013 ◽  
Vol 6 (4) ◽  
pp. 7565-7591
Author(s):  
T. Lurton ◽  
J.-B. Renard ◽  
D. Vignelles ◽  
M. Jeannot ◽  
R. Akiki ◽  
...  
Keyword(s):  
Light Scattering ◽  
Small Angle ◽  
Dynamic Range ◽  
Roughness Parameter ◽  
Particle Sizes ◽  
Angular Aperture ◽  
Scattering Angle ◽  
Set Up ◽  
Theoretical Results ◽  
Good Agreement

Abstract. We investigated the behaviour of light scattering by particulates of various sizes (0.1 μm to 100 μm) at a small scattering angle. It was previously shown that for a small angle, the scattered intensities are weakly dependent upon the particulates' nature (Renard et al., 2010). Particles found in the atmosphere exhibit roughness that leads to large discrepancies with the classical Mie solution in terms of scattered intensities in the low angular set-up. This article focuses on building an effective theoretical tool to predict the behaviour of light scattering by real particulates at a small scattering angle. We expose both the classical Mie theory and an adaptation to the case of rough particulates with a fairly simple roughness parametrisation. An experimental device was built, corresponding to the angular set-up of interest (low scattering angle and therefore low angular aperture), and measurements are presented that confirm the theoretical results with a good agreement. It is found that the differences between the classical Mie solution and actual measurements, especially for large particulates, can be attributed to the roughness of particulates. It is also found that, in this low angular set-up, saturation of the scattered intensities occurs for relatively small values of the roughness parameter. This confirms the low variability in the scattered intensities for particulates of different kinds. A direct interest of this study is a broadening of the dynamic range of optical counters: using a small angle of aperture for measurements allows greater dynamics in terms of particle size, and thus enables a single device to observe a broad range of particle sizes whilst utilising the same electronics.

Fe3O4@L-arginine as a Reusable Catalyst for the Synthesis of Polysubstituted 2-Pyrrolidinones

2019 ◽  
Vol 6 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Mohammad Ali Ghasemzadeh ◽  
Mohammad Hossein Abdollahi-Basir ◽  
Zahra Elyasi
Keyword(s):  
Heterocyclic Compounds ◽  
Structure Elucidation ◽  
Reaction Times ◽  
Biologically Active ◽  
Reusable Catalyst ◽  
Particle Sizes ◽  
Magnetic Nanocatalyst ◽  
Green Method ◽  
One Step ◽  
Good Agreement

Background: This research introduces an effective and green method for the synthesis of polysubstituted 2-pyrrolidinone derivatives as biologically-active heterocyclic compounds using multi- component reactions using Fe3O4@L-arginine as a reusable organocatalyst. Material and Method: The Fe3O4@L-arginine nanoparticles were prepared by a facile one-step approach and the structure elucidation of the magnetic nanocatalyst has been done using various spectroscopy techniques. Results: L-arginine-functionalized magnetite nanoparticles were obtained with particle sizes around 10 nm. Fe3O4@L-arginine exhibited strong catalytic activity to obtain some polysubstituted 2- pyrrolidinone. Conclusion: The considerable advantages of this research are short reaction times, excellent yields, simple workup procedure and reusability of the nanocatalyst which is in good agreement with green chemistry disciplines. The study on the reusability of the Fe3O4@L-arginine nanoparticles showed that the recovered catalyst could be reused six consecutive times.

Droplet dynamics in mixed flow conditions: Effect of shear/elongation balance and viscosity ratio

2010 ◽  
Vol 54 (6) ◽  
pp. 1285-1306 ◽  
Author(s):  
Elia Boonen ◽  
Peter Van Puyvelde ◽  
Paula Moldenaers
Keyword(s):  
Viscosity Ratio ◽  
Flow Conditions ◽  
Mixed Flow ◽  
Droplet Dynamics

Results of the IES Cleanroom Flow Modeling Exercise

1992 ◽  
Vol 35 (2) ◽  
pp. 37-48
Author(s):  
Thomas Kuehn ◽  
David Pui ◽  
James Gratzek
Keyword(s):  
Experimental Data ◽  
Flow Pattern ◽  
Working Group ◽  
Particle Concentration ◽  
Numerical Models ◽  
Computer Applications ◽  
Flow Modeling ◽  
Airflow Velocity ◽  
Velocity Magnitude ◽  
Good Agreement

Six contributed solutions to the Cleanroom Flow Modeling Exercise sponsored by the IES Computer Applications/ Cleanroom Modeling and Evaluation Working Group are compared with each other and with experimental data obtained in a cleanroom configuration similar to that defined in the exercise. Quantitative comparisons are given for time-averaged airflow velocity magnitude and direction and particle concentration. The good agreement between the measured and computed velocity results shows that numerical models can accurately predict the flow pattern in this configuration. However, the particle concentration agreement is not as good.

Effects of Inertia and Viscosity on Single Droplet Deformation in Confined Shear Flow

2013 ◽  
Vol 13 (3) ◽  
pp. 706-724 ◽  
Author(s):  
Samaneh Farokhirad ◽  
Taehun Lee ◽  
Jeffrey F. Morris
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
Viscous Fluid ◽  
Lattice Boltzmann ◽  
Viscosity Ratio ◽  
Diffuse Interface ◽  
Single Droplet ◽  
Droplet Deformation ◽  
Droplet Dynamics ◽  
Lattice Boltzmann Simulations

AbstractLattice Boltzmann simulations based on the Cahn-Hilliard diffuse interface approach are performed for droplet dynamics in viscous fluid under shear flow, where the degree of confinement between two parallel walls can play an important role. The effects of viscosity ratio, capillary number, Reynolds number, and confinement ratio on droplet deformation and break-up in moderately and highly confined shear flows are investigated.

scholarly journals Effect of Temperature and Nanoparticle Concentration on the Viscosity of Glycerine-water based SiO2 Nanofluids

2021 ◽  
Vol 10 (4) ◽  
pp. 111-116
Author(s):  
M.L.R. Chaitanya Lahari ◽  
◽  
P. Haseena Bee ◽  
P.H.V. Sesha Talpa Sai ◽  
K.S. Narayanaswamy ◽  
...  
Keyword(s):  
Particle Concentration ◽  
Viscosity Ratio ◽  
Effect Of Temperature ◽  
Viscosity Data ◽  
Nanoparticle Concentration ◽  
Water Based ◽  
Glycerine Water ◽  
Water Base ◽  
Base Liquid ◽  
Newtonian Behavior

Dynamic viscosity of SiO2/22nm nanofluids prepared in a glycerine-water (30:70 by volume) mixture base liquid, referred to as GW70, is measured experimentally. Nanofluids with concentrations of 0.2, 0.6, and 1.0 percent are produced, and viscosity measurements are carried out at temperatures ranging from 20 to 80 oC using a LVDV-2T model Brookfield Viscometer. The particle size and elemental composition of nanoparticles are determined using FESEM and EDX. XRD images confirm the SiO2 peaks in the crystalline structure. The rheology of nanofluids is influenced by the nanoparticle’s concentration. In the experimental temperature and concentration range, nanofluids show Newtonian behavior. The viscosity of nanofluids enhanced as particle concentration increased and reduced as temperature increased. For 1.0 percent vol. concentration at 20oC, the maximum viscosity value is achieved, and for 0.2 percent vol. concentration at 80oC, the lowest viscosity value is observed. The viscosity of the glycerine-water base fluid was also determined at 20, 40, 60, and 80 degrees Celsius. The viscosity ratio of nanofluids to the base liquid is found to be more than one for all the nanofluids. This viscosity data is useful to estimate HTC of glycerine-water-based silica nanofluids.

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