Molecular dynamics simulations for the shear viscosity and self-diffusion coefficient of pure water were performed to investigate the effect of including intramolecular degrees of freedom in simple point charge (SPC) models over a wide range of state points. Results are reported for the flexible SPC/Fw model, its rigid SPC counterpart, and the widely used SPC/E model. The simulations covered th...

In this paper we revisit the issue of the propagation of warps in thin and viscous accretion discs. In this regime warps are know to propagate diffusively, with a diffusion coefficient approximately inversely proportional to the disc viscosity. Previous numerical investigations of this problem (Lodato & Pringle 2007) did not find a good agreement between the numerical results and the prediction...

The Phragmén-Lindelöf theorem for Lp-viscosity solutions of fully nonlinear second order elliptic partial differential equations with unbounded coefficients and inhomogeneous terms is established.

We study the constant stress and pressure rheology of dense hard-sphere colloidal suspensions using Brownian dynamics simulation. Expressing the flow behavior in terms of the friction coefficient-the ratio of shear to normal stress-reveals a shear arrest point from the collapse of the rheological data in the non-Brownian limit. The flow curves agree quantitatively (when scaled) with the experim...

The ultrasonic velocity (U), density ( ρ) and viscosity (η) measurements have been carried out for four amino acids namely L-alanine, L-leucine, L-valine and L-proline in aqueous sodium acetate solution as a function of composition at 303, 308 and 313K. Experimental data have been used to estimate the adiabatic compressibility (β), change in adiabatic compressibility (∆β), relative change in ad...

Ultrasonic velocities in solution of tetrabutylammonium bromide (TBAB) in 10, 20 and 30 %w/w N, N– dimethylformamide (DMF)-water mixtures were measured at 303 K, 308 K and 313 K by using the pulse echo overlap method at a frequency of 3 MHz. The ultrasonic velocity, density, and viscosity were used to calculate the adiabatic compressibility, apparent molal compressibility, apparent molal volume...

We investigate the behavior of the shear viscosity eta(p) and the mass-dependent diffusion coefficient D(m,p) in the context of a simple model that, as the cross link density p is increased, undergoes a continuous transition from a fluid to a gel. The shear viscosity diverges at the gel point according to eta(p) approximately (p(c)-p)(-s) with s approximately 0.65. The diffusion constant shows ...

We prove the global existence of weak solutions for the 2-D compressible Navier-Stokes equations with a density-dependent viscosity coefficient (λ = λ(ρ)). Initial data and solutions are small in energy-norm with nonnegative densities having arbitrarily large sup-norm. Then, we show that if there is a vacuum domain at the initial time, then the vacuum domain will retain for all time, and vanish...

Electron spin resonance was used to measure the diffusion of a small (Mr 170) spin label in the aqueous cytoplasm of mammalian cells. Translational and rotational motion were determined from the same spectra. Based on measurements made in model systems, it was hypothesized that calculations of the apparent viscosity from either rotational or translational motion would distinguish between the ef...