– We study the effects of externally applied shear flow on a model of suspensions of motors and filaments, via the equations of active hydrodynamics [PRL 89 (2002) 058101; 92 (2004) 118101]. In the absence of shear, the orientationally ordered phase of both polar and apolar active particles is always unstable at zero-wavenumber. An imposed steady shear large enough to overcome the active stress...

We report the results of a theoretical study of the stability of a Couette flow of dilute and concentrated suspensions of stiff fibers. The Ericksen anisotropic fluid rheological equation of state in the wide-gap situation is used to compute the critical Taylor number and wavenumber of the suspension as a function of the aspect ratio of the fibers and the gap-width

Under an applied traction, highly concentrated suspensions of solid particles in fluids can turn from a state which they flow to counteract the traction as elastic solid: shear-jammed state. Remarkably, suspension back flowing simply by inverting traction. A tensorial model is presented and tested paradigmatic cases. We show that, reproduce phenomenology shear jamming generic geometries, it nec...

We present data for the rheology of suspensions of monodisperse particles of varying aspect ratio, from oblate to prolate, and covering particle volume fractions φ from dilute to highly concentrated. Rheology is characterized by fitting the experimental data to the model of Herschel & Bulkley (Herschel & Bulkley 1926 Kolloid Z. 39, 291–300 (doi:10.1007/BF01432034)) yielding three rheometric par...

A generation of tissue-specific stable ultrasound contrast agent (UCA) composed of a polymeric capsule with a perfluorocarbone liquid core has become available. Despite promising uses in clinical practice, the acoustical behavior of such UCA suspensions remains unclear. A simulation code (2-D finite-difference time domain, FDTD) already validated for homogeneous particles [Galaz Haiat, Berti, T...

Simulations describing the settling of suspensions of solid particles bounded by a rigid container are presented. Results are compared with previous simulations of homogeneous suspensions with periodic boundary conditions. Velocity fluctuations in vertically inhomogeneous suspensions are found to saturate under conditions similar to those found in laboratory experiments, while in vertically hom...

Using particle tracking microrheology, we studied the glass transition in dense suspensions of thermosensitive microgel particles. These suspensions can be tuned reversibly between the glass state at low temperature and the liquid state at high temperature. In the glass state, the ensemble averaged mean squared displacements (MSDs) of added fluorescent tracer particles depend on the age of the ...

Nanoparticle technology represents an attractive approach for formulating poorly water-soluble pulmonary medicines. Unfortunately, nanoparticle suspensions used in nebulizers or metered dose inhalers often suffer from physical instability in the form of uncontrolled agglomeration or Ostwald ripening. In addition, processing such suspensions into dry powders can yield broad particle size distrib...

We present an efficient, accurate, and robust method for simulation of dense suspensions of deformable and rigid particles immersed in Stokesian fluid in two dimensions. We use a well-established boundary integral formulation for the problem as the foundation of our approach. This type of formulation, with a high-order spatial discretization and an implicit and adaptive time discretization, hav...

Impressive enhancements of the storage modulus have been documented when low volume fractions of single wall carbon nanotubes (SWNTs) are added to a Newtonian solvent for obtaining dilute suspensions. The intrinsic bending dynamics of carbon nanotubes (CNTs) has been proposed to explain such elasticity. CNTs contain topological defects inducing naturally bent structures in absence of external f...