A mesoscopic model of a diblock copolymer is used to study the stability of a lamellar structure under a uniform shear flow. We first obtain the nonlinear lamellar solutions under both steady and oscillatory shear flows. Regions of existence of these solutions are determined as a function of the parameters of the model and of the flow. Finally, we address the stability of the lamellar solution ...

The degradation stability towards mechanical shearing (shear stability) of poly(methyl methacrylate) (PMMA) and its copolymer with styrene at different level of concentrations have been investigated. With a view to understanding the relationship between the thickening performance (percent increase in viscosity of the solvent in the additive of the unit weight of polymers) and shear stability of...

BACKGROUND Flow chambers allow the ex vivo study of platelet response to defined surfaces at controlled wall shear stresses. However, most assays require 1-10 mL of blood and are poorly suited for murine whole blood experiments. OBJECTIVE To measure murine platelet deposition and stability in response to focal zones of prothrombotic stimuli using 100 microL of whole blood and controlled flow ...

The magnetohydrodynamic ~MHD! stability of negative central magnetic shear toroidal equilibria with q.2 everywhere and ebpol@1 is investigated. Here, q is the safety factor of the equilibrium magnetic field in a torus with inverse aspect ratio e , and bpol is the ratio of the plasma pressure to the pressure in the poloidal magnetic field. At small ebpol!1, the elimination of the q52 resonant su...

[1] Velocity, temperature, and specific humidity data collected by aircraft at 20-Hz resolution are analyzed for stability and turbulence parameters. Over 100 vertical profiles (mostly over the ocean) with a total of over 300 km in vertical airspace sampled are used. The compiled statistics show that anisotropy in the velocity fluctuations prevail down to the smallest spatial separations measur...

The 3' poly(A) tail is important in messenger RNA stability and translational efficiency. In somatic tissues, 3' polyadenylation of mRNAs has been thought to largely be a constitutively active process. We have reported that laminar shear stress causes a brief increase in endothelial nitric oxide synthase (eNOS) transcription, followed by a prolonged increase in eNOS mRNA stability. We sought to...

For a perfectly conducting, cylindrical plasma equilibrium ("screw-pinch"), the spectrum contains four distinct continua, three of which can extend to the origin. This implies the existence of irreversible damping and heating in the nondissipative model. The continuum becomes (Suydam) unstable by instantly shedding an infinite number of point eigenvalues. More generally, any local instability i...

The effect of heparin on thrombogenesis induced by the subendothelium of rabbit aorta was investigated in 24 healthy volunteers after intravenous injection of different doses (0, 1000, 2500, and 5000 IU). By using an ex vivo perfusion chamber system, the interaction between flowing blood and exposed subendothelium was measured at low (50 s-1), intermediate (650 s-1), and high (2600 s-1) wall sh...

We examine the linear stability of fluid interfaces subjected to a shear flow. Our main object is to generalize previous work to an arbitrary Atwood number, and to allow for surface tension and weak compressibility. The motivation derives from instances in astrophysical systems where mixing across material interfaces driven by shear flows may significantly affect the dynamical evolution of thes...