A Mechanism for Non-Newtonian Flow in Suspensions of Rigid Spheres

Krieger, Irvin M.; Dougherty, Thomas J.

doi:10.1122/1.548848

Cited by 2,846 publications

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“…The incremental influence of this particle on the overall viscosity is assumed to be independent of the suspension density itself, and is therefore, in extensional flows, equal to the intrinsic viscosity coefficient of a dilute suspension, 28,30 for the relative extensional viscosity of a non-dilute suspension,…”

Section: Rheologymentioning

confidence: 99%

Motility induced changes in viscosity of suspensions of swimming microbes in extensional flows

McDonnell

Gopesh

et al. 2015

Soft Matter

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Suspensions of motile cells are model systems for understanding the unique mechanical properties of living materials which often consist of ensembles of self-propelled particles. We present here a quantitative comparison of theory against experiment for the rheology of such suspensions. The influence of motility on viscosities of cell suspensions is studied using a novel acousticallydriven microfluidic capillary-breakup extensional rheometer. Motility increases the extensional viscosity of suspensions of algal pullers, but decreases it in the case of bacterial or sperm pushers. A recent model [Saintillan, Phys. Rev. E, 2010, 81, 56307] for dilute active suspensions is extended to obtain predictions for higher concentrations, after independently obtaining parameters such as swimming speeds and diffusivities. We show that details of body and flagellar shape can significantly determine macroscale rheological behaviour.

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Section: Rheologymentioning

confidence: 99%

Motility induced changes in viscosity of suspensions of swimming microbes in extensional flows

McDonnell

Gopesh

et al. 2015

Soft Matter

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“…Figure 7 shows the variation of the relative viscosity, η r , with volume fraction, φ, for PS core particle dispersions with a mean diameter of 321 nm. For comparison the η r -φ curves calculated using the Dougherty-Krieger [32] equations is shown on the same figure.…”

Section: Determination Of the Adsorbed Layer Thickness Using Rheologymentioning

confidence: 99%

Interaction forces between particles stabilized by a hydrophobically modified inulin surfactant

Nestor

Esquena

Solans

et al. 2007

Journal of Colloid and Interface Science

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The adsorption isotherm of a hydrophobically modified inulin (INUTEC SP1) on Polystyrene (PS) and Poly(methyl methacrylate) (PMMA) particles was determined. The results show a high affinity isotherm for both particles as expected for a polymeric surfactant adsorption. The interactions forces between two layers of the hydrophobically modified inulin surfactant adsorbed onto a glass sphere and plate was determined using a modified atomic force microscope (AFM) apparatus. In the absence of any polymer, the interaction was attractive although the energy of interaction was lower than predicted by the van der Waals forces. The results between two layers of the adsorbed polymer confirms the adsorption isotherms results and provides an explanation to the high stability of the particles covered by INUTEC SP1 at high electrolyte concentration. Stability of dispersions against strong flocculation could be attributed to the conformation of the polymeric surfactant at the solid/liquid interface (multipoint attachment with several loops) which remains efficient at Na 2 SO 4 concentration reaching 1.5 mol.dm -3 . The thickness of the adsorbed polymer layer in water determined both by AFM and rheology measurements, was found to be about 9 nm.3

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“…There have been various studies to illustrate the behavior of suspensions and suggested some viscosity models (Liu 2000;Krieger 1959;Chong and Baer 1971;Farris 1968). When taking into account the concrete, suggested viscosity models can be divided into two categories depending on the scale-level of constituents: unimodal suspension model and multimodal suspension model.…”

Section: Effects Of Particle Concentration and Particle Shape On Rheomentioning

confidence: 99%

“…Various rheological models (Hafid et al 2010;Chateau and Trung 2008;Liu 2000;Krieger 1959;Chong and Baer 1971;Farris 1968) were suggested to describe the rheological behavior of suspension. However, very few studies have been performed to establish comprehensive prediction methodology for concrete pumping, that is, there have been few studies investigating the role of these rheological models on determining the pipe flow of pumped concrete, more specifically, for the formation and material properties of lubrication layer.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Concrete Pumping Using Various Rheological Models

Choi

Kim

2014

Int J Concr Struct Mater

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When concrete is being transported through a pipe, the lubrication layer is formed at the interface between concrete and the pipe wall and is the major factor facilitating concrete pumping. A possible mechanism that illustrates to the formation of the layer is the shear-induced particle migration and determining the rheological parameters is a paramount factor to simulate the concrete flow in pipe. In this study, numerical simulations considering various rheological models in the shear-induced particle migration were conducted and compared with 170 m full-scale pumping tests. It was found that the multimodal viscosity model representing concrete as a three-phase suspension consisting of cement paste, sand and gravel can accurately simulate the lubrication layer. Moreover, considering the particle shape effects of concrete constituents with increased intrinsic viscosity can more exactly predict the pipe flow of pumped concrete.

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A Mechanism for Non-Newtonian Flow in Suspensions of Rigid Spheres

Cited by 2,846 publications

References 0 publications

Motility induced changes in viscosity of suspensions of swimming microbes in extensional flows

Motility induced changes in viscosity of suspensions of swimming microbes in extensional flows

Interaction forces between particles stabilized by a hydrophobically modified inulin surfactant

Prediction of Concrete Pumping Using Various Rheological Models

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