The dynamical interaction between eddies and shear flow is investigated through a simplified model of vorticity conservation with tilted eddies. Energy is transfered either to the flow or to eddies, depending on the eddy tilt with respect to the flow shear. When eddies are tilted in the shear direction, the system is favorable to shear increase: tilt instability or negative viscosity phenomenon...

Quasi-static cyclic tests on reinforced concrete (RC) walls have shown that shear deformations can constitute a significant ratio of the total deformations when the wall is loaded beyond the elastic regime. For slender RC walls that form a stable flexural mechanism, the ratio of shear to flexural deformations remains approximately constant over the entire range of imposed displacement ductiliti...

We perform numerical experiments with a novel cellularautomaton fluid model. The model has simple pair-interaction rules and works in arbitrarily many dimensions; here we consider the twodimensional case. By observing the smoothing-out of the velocity profile of a shear flow and the relaxation of a shear wave, we measure the kinematic shear viscosity and obtain a value of :::::: 0.5. To demonst...

Initial platelet arrest at the exposed arterial vessel wall is mediated through glycoprotein Ibα binding to the A1 domain of von Willebrand factor. This interaction occurs at sites of elevated shear force, and strengthens upon increasing hydrodynamic drag. The increased interaction requires shear-dependent exposure of the von Willebrand factor A1 domain, but the contribution of glycoprotein Ibα...

[1] Using 1D Vlasov drift-kinetic computer simulations, it is shown that electron trapping in long period standing shear Alfvén waves (SAWs) provides an efficient energy sink for wave energy that is much more effective than Landau damping. It is also suggested that the plasma environment of low altitude auroral-zone geomagnetic field lines is more suited to electron acceleration by inertial or ...

Calin from the saliva of the medicinal leech, Hirudo medicinalis, is a potent inhibitor of collagen mediated platelet adhesion and activation. In addition to inhibition of the direct platelet-collagen interaction, we presently demonstrate that binding of von Willebrand to coated collagen can be prevented by Calin, both under static and flow conditions in agreement with the occurrence of binding...

In this paper we develop a lattice Boltzmann algorithm to simulate red blood cell (RBC) behavior in shear flows. The immersed boundary method is employed to incorporate the fluid-membrane interaction between the flow field and deformable cells. The cell membrane is treated as a neo-Hookean viscoelastic material and a Morse potential is adopted to model the intercellular interaction. Utilizing t...

Information personalization is fertile ground for application of AI techniques. In this article I relate personalization to the ability to capture partial information in an information-seeking interaction. The specific focus is on personalizing interactions at web sites. Using ideas from partial evaluation and explanation-based generalization, I present a modeling methodology for reasoning abou...

Shear stress is one of mechanical constraints which are exerted by blood flow on endothelial cells (ECs). To adapt to shear stress, ECs align in the direction of flow through adherens junction (AJ) remodeling. However, mechanisms regulating ECs alignment under shear stress are poorly understood. The scaffold protein IQ domain GTPase activating protein 1 (IQGAP1) is a scaffold protein which coup...

The shear strength of cohesionless granular materials is generally attributed to the compactness or anisotropy of their microstructure. An open issue is how such compact or anisotropic microstructures, and thus the shear strength, depend on the particle properties. We first recall the role of fabric and force anisotropies with respect to the critical-state shear stress. Then, a model of accessi...