I give a physical explanation of what shear viscosity is, and what physics determines its value. Then I explain why determining the shear viscosity of the Quark-Gluon Plasma is interesting. I outline the leading-order calculation of the QGP shear viscosity (and baryon number diffusion constant), explaining why the quite complicated physics of parton splitting and Landau-Pomeranchuk-Migdal inter...

The weak gravitational lensing of distant galaxies by large-scale structure is expected to become a powerful probe of dark energy. By measuring the ellipticities of large numbers of background galaxies, the subtle gravitational distortion called “cosmic shear” can be measured and used to constrain dark energy parameters. The observed galaxy ellipticities, however, are induced not by shear but b...

Vascular endothelial cells (EC) are continuously exposed to shear stress associated with the flowing blood. Over the years, it has become clear that such shear exerts a multitude of effects on endothelial biology and vascular function and structure, ranging in time span from seconds to months. On the scale of seconds, shear-dependent vasodilation has been demonstrated in many experimental setti...

Background: The interaction between the blood and the vessel wall is of great clinical interest in studying cardiovascular diseases, the major causes of death in developed countries.Objective: To understand the effects of incorporating fluid-structure interaction into the simulation of blood flow through an anatomically realistic model of abdominal aorta and renal arteries reconstructed from CT...

Endothelial cells (ECs) are constantly exposed to shear stress, the action of which triggers signaling pathways and cellular responses. During inflammation, cytokines such as IL-6 increase in plasma. In this study, we examined the effects of steady flow on IL-6-induced endothelial responses. ECs exposed to IL-6 exhibited STAT3 activation via phosphorylation of Tyr705. However, when ECs were sub...

Incipient clot formation in whole blood and fibrin gels was studied by the rheometric techniques of controlled stress parallel superposition (CSPS) and small amplitude oscillatory shear (SAOS). The effects of unidirectional shear stress on incipient clot microstructure, formation kinetics and elasticity are reported in terms of the fractal dimension (df) of the fibrin network, the gel network f...

The final structure of molten syndiotactic polypropylene (sPP) sheared under different conditions was investigated by synchrotron small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (WAXD) techniques to elucidate the shear effects on sPP crystalline structure. The results obtained from the WAXD show that there is no variation on crystalline form but a little difference on the o...

bond failure of brackets during orthodontic treatment is a common problem; which results in treatment interference, increased treatment time and prolonged clinical time for rebonding of failed brackets. the purpose of this study was to evaluate the effects of coca-cola and a non-alcoholic beer on the shear bond strength and adhesive remnant index (ari) of orthodontic metal brackets in vitro.eig...

An experimental study was conducted to investigate the structural stability of ethylene glycol-based titanium dioxide nanoparticle suspensions (nanofluids) prepared by two-step method. The effects of particle concentration, fluid temperature, shear rate and shear duration were examined. Particle size and thermal conductivity measurements in quiescent state indicated the existence of aggregates ...

Shear viscous drag within the thin fluid film at the contact between grains in water-saturated sand is an important loss mechanism for high-frequency sound in the Biot-Stoll plus contact squirt flow and shear viscous drag (BICSQS) model [J. Acoust. Soc. Am. 116, 2011-2022 (2004)]. Couette flow was assumed for the shear drag but it breaks down when inertial effects within the film become signifi...