We observe a shear-flow-induced phase transition in wormlike micelle solutions which depends on whether the applied stress or the applied shear rate is held constant. When the shear stress is held constant, the system macroscopically phase separates into two coexisting phases with a single stable interface between them. By contrast, when the shear rate is held constant, the system still undergo...

In vivo microscopy was used to assess the relationships among shear rate (and shear stress), leukocyte rolling velocity, and leukocyte adherence in a cat mesentery preparation. Shear rate in individual venules and arterioles of 25-35 microns diameter were varied over a wide range by graded occlusion of an arterial loop. There was a linear decline in leukocyte rolling velocity (Vwbc) as red cell...

Shear localization has been observed in liquid lubricants flowing at high pressure. Two kinds have been identified: for stresscontrolled plane Couette shear at high values of Nahme No., thermal runaway can result in the appearance of a band at midplane where the temperature and shear rate become localized. Alternatively, at high pressure and high shear stress, intermittent slip can be visualize...

The formation and properties of alginate fluid gels produced using in-situ calcium release and a defined shear field are investigated. Results show that, while the rate of particle growth during formation increases significantly upon lowering the shear rate, the rate of inter-particle interaction post-production remains unaffected by the

A non-intrusive technique has been developed for measuring agglomeration rate constants (β0) in a constant shear field. A particulate suspension with a mean particle diameter, d, of about 10 μm is introduced in an optically accessible cylindrical Couette flow device. The suspension is illuminated by means of a pulsed laser and observed with a CCD camera. The recorded images are analysed off-lin...

The dynamics of a single polymer tethered to a solid surface in a shear flow was observed using fluorescently labeled DNA chains. Dramatic shear enhanced temporal fluctuations in the chain extension were observed. The rate of these fluctuations initially decreased for increasing shear rate gamma; and increased above a critical gamma;. Simulations revealed that these anomalous dynamics arise fro...

Wepresent results from laboratory experiments and anumericalmodel for frictional weakening and shear localization. Experiments document strain localization in sheared layers at normal stresses of 0.5 to 5MPa, layer thicknesses of 3 to 10mm, and imposed slip velocities of 10 to 100 μm/s. Passive strain markers and the response to load perturbations indicate that the degree of shear localization ...

Dynamic response of microemulsions to shear deformation on the basis of twoorder-parameter time dependent Ginzburg-Landau model is investigated by means of cell dynamical system approach. Time evolution of anisotropic factor and excess shear stress under steady shear flow is studied by changing shear rate and total amount of surfactant. As the surfactant concentration is increased, overshoot pe...

We study the rheology of cornstarch suspensions, a non-Brownian particle system that exhibits shear thickening. From magnetic resonance imaging velocimetry and classical rheology it follows that as a function of the applied stress the suspension is first solid (yield stress), then liquid, and then solid again when it shear thickens. For the onset of thickening we find that the smaller the gap o...

We investigate the rheograms of concentrated suspensions of magnetic particles obtained under imposed shear rate in parallel plate geometry. We show that under magnetic field application the usual trend of the rheogram, i.e., increasing shear stress for the whole range of shear rates, is altered by the appearance of a region in which the shear stress decreases as the shear rate is increased. Th...