Erratum: Viscosity of a concentrated suspension of rigid monosized particles [Phys. Rev. E81, 051402 (2010)]

2010 ◽  
Vol 82 (4) ◽  
Author(s):  
H. J. H. Brouwers
2021 ◽  
pp. 131793
Author(s):  
Yuxuan Wu ◽  
Wenhui Wang ◽  
Junshuo Zhang ◽  
Min Sang ◽  
Yunqi Xu ◽  
...  

2009 ◽  
Vol 15 (S3) ◽  
pp. 25-26
Author(s):  
J. Méndez ◽  
J. B. Rodríguez ◽  
R. Álvarez-Otero ◽  
M. J. I. Briones ◽  
L. Gago-Duport

AbstractThe earthworm species belonging to the Lumbricidae family (Annelida, Oligochaeta) posses a complex oesophageal organ known as “calciferous gland” which secretes a concentrated suspension of calcium carbonate. Previous studies have demonstrated the non-crystalline structure of this calcareous fluid representing an interesting example of biomineralisation.


2015 ◽  
Vol 645-646 ◽  
pp. 394-399
Author(s):  
Wei Gao ◽  
Qi Long Wei ◽  
Ling Ding ◽  
Xiao Yuan Li ◽  
Chao Wang ◽  
...  

A multi-scale method was developed, which utilized intrinsic relationships among zeta potential of particles, rheological properties of suspensions and particle size distribution (PSD), to analyze dispersion behavior of nanoparticles in concentrated suspensions. It was found that PSD of a kind of nanoceria particles by dynamic light scattering (DLS) method in solution A with concentration 5 wt% accorded well with that by direct TEM analysis, which meant the particles had been dispersed well. However, there had a significant difference when the concentration was increased to 20 wt%. When particles concentration increased from 5 wt% to 20 wt%, zeta potential in solution A changed from-150 mV to-100 mV, while zeta potential in solution B changed from-35mV to-45 mV. Variations of zeta potential of particles accorded well with rheological properties of suspensions too, from phenomenological models. When the suspensions composed by solution A and the nanoparticles with concentration about 20 wt% was diluted with its original solution to 5 wt%, the PSD of nanoceria could be measured indirectly, which accorded well with both that of a suspension prepared directly with near concentration and that from TEM images. Then a method to measure PSD of nanoparticles in concentrated suspension was brought forward.


2008 ◽  
Vol 72 (1) ◽  
pp. 227-231 ◽  
Author(s):  
M. J. I. Briones ◽  
E. López ◽  
J. Méndez ◽  
J. B. Rodríguez ◽  
L. Gago-Duport

AbstractThe earthworm calciferous gland produces a concentrated suspension of calcium carbonate and in certain species precipitates as concretions of CaCO3, which then enter the soil. Here we investigated the initial stages of CaCO3 formation in the earthworm Lumbricus friendi by means of Fourier transform infrared and electron microscopy techniques (field-emission scanning electron microscopy, transmission electron microscopy, high resolution electron microscopy and selected area electron diffraction). In addition, comparisons between the IR spectra of the water-dissolved carbonic anhydrase (CA) and the glandular secretion (‘milky fluid’) were performed in order to investigate the mechanisms involved in CaCO3 precipitation. Our results strongly suggest that carbonation starts with the dissolved CO2, which is transformed via deprotonation to HCO3-, then to CO32- and finally to amorphous calcium carbonate (ACC). While ACC stabilization takes place under the biological control, further transformation stages leading to calcite concretions seem to be inorganically driven by an Ostwald ripening process.


1991 ◽  
Vol 24 (5) ◽  
pp. 221-232 ◽  
Author(s):  
Xu Fei Wu ◽  
N. Kosaric

An upflow alum-flocculated algae photobioreactor was investigated for removal of toxic chlorinated organic compounds, chlorobenzene and 2,4-dichlorophenol. Biodegradation was evaluated by monitoring substrate disappearance and concurrent generation of artifacts. Chlorobenzene disappeared faster than 2,4-dichlorophenol. Relative rates of removal were greater by the live than by the dead algae biomass. In this study, gravity-concentrated, suspension-centrifuged, and alum-flocculated algae biomass cultures of Chlorella and Scenedesmus were used. In batch and continuous upflow photobioreactor experiments to treat wastewaters containing 50, 100, 200 (batch), and 1,000 mg/l (continuous) each of chlorobenzene and 2,4-dichlorophenol were applied to the bioreactors individually and also as a mixture. The continuous upflow photobioreactor system was found to be efficient, versatile, adaptable and easy to operate for removal and biodegradation of these organochlorine compounds.


2013 ◽  
Vol 734 ◽  
pp. 219-252 ◽  
Author(s):  
Arun Ramachandran

AbstractA two-time-scale perturbation expansion is used to derive a cross-section-averaged convection–dispersion equation for the particle distribution in the flow of a concentrated suspension of neutrally buoyant, non-colloidal particles through a straight, circular tube. Since the cross-streamline motion of particles is governed by shear-induced migration, the Taylor-dispersion coefficient ${\mathscr{D}}_{eff} $ scales as ${U}^{\prime } {R}^{3} / {a}^{2} $, ${U}^{\prime } $, $R$ and $a$ being the characteristic velocity scale, the tube radius and the particle radius, respectively. Here ${\mathscr{D}}_{eff} $ is found to decrease monotonically with an increase in the particle concentration. The linear dependence of ${\mathscr{D}}_{eff} $ on ${U}^{\prime } $ implies that changes in the cross-section averaged axial concentration profile are dependent only on the total axial strain experienced by the suspension. This stipulates that the spatial evolution of a fluctuation in the concentration of particles in the flowing suspension, or the width of the mixing zone between two regions of different concentrations in the tube will be independent of the suspension velocity in the tube. A second interesting feature in particulate dispersion is that the effective velocity of the particulate phase is concentration-dependent, which, by itself (i.e. without considering Taylor dispersion), can produce either sharpening or relaxation of concentration gradients. In particular, shocks with positive concentration gradients along the flow direction can asymptotically evolve into time-independent distributions in an appropriately chosen frame of reference, and concentration pulses relax asymmetrically. These trends are contrasted with those expected from the classical problem of Taylor dispersion of a passive tracer in the same geometry. The results in this paper are especially relevant for suspension flows through microfluidic geometries, where the induction lengths for shear-induced migration are short.


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