The nonlinear rheological properties of dense suspensions are discussed within simplified models, suggested by a recent first principles approach to the model of Brownian particles in a constant-velocity-gradient solvent flow. Shear thinning of colloidal fluids and dynamical yielding of colloidal glasses arise from a competition between a slowing down of structural relaxation, because of partic...

The validity of potential flow analogy by the Hele-Shaw flow of non-Newtonian fluids is examined through experiments using two shear-thinning elastic polymer solutions for three different flow configurations, i.e. flows around a circular cylinder and a square cylinder and flows through an abruptly converging-diverging channel (slit). Although the polymer solutions are highly shear-thinning and ...

In this study, we use micro-particle image velocimetry (μ-PIV) and adapt a commercial birefringence microscopy system for making full-field, quantitative measurements of flow-induced birefringence (FIB) for the purpose of microfluidic, opticalrheometry of two worm-like micellar solutions. In combination with conventional rheometric techniques, we use our microfluidic rheometer to study the prop...

Plants gums are complex mixtures of different polysaccharides with a variety of biological activities and pharmaceutical applications. Few studies have focused on physicochemical and biological properties of gums obtained from different plants. This study was designed to determine potential pharmaceutical and pharmacological values of the gum exudates and its isolated biopolymers obtained from ...

We study the stationary and transient behaviors of a microemulsion phase subjected to a shear flow. The system is described by a diffusion-convective equation that generalizes the usual Cahn-Hilliard equation. Nonlinear terms are treated in a self-consistent approximation. Shear, first and second normal stresses are calculated as momenta of the structure factor. Shear thinning is observed in st...

Multilayer sol-gel optical high reflectors with greater than 99% reflection have been prepared on substrates up to 20 cm in diameter by spin coating silica/alumina colloidal suspensions. These coatings are radially nonuniform, owing to the extensive shear-thinning rheology of the high-index alumina suspension. To a large degree the film thickness nonuniformity can be compensated for by the refl...

The paper is focused to the experimental investigations of weakly elastic viscous flows in complex geometries, with application in biofluid mechanics. The test samples, polyacrylamide solutions in water characterized by very low relaxation times ( λ < 0.01 s), have similar shear rheology with blood at medium and high shear rates. The flow configuration is a special designed “T” branch Hele – Sh...