3,030 research outputs found
Hydrophobic interactions with coarse-grained model for water
Integral equation theory is applied to a coarse-grained model of water to
study potential of mean force between hydrophobic solutes. Theory is shown to
be in good agreement with the available simulation data for methane-methane and
fullerene-fullerene potential of mean force in water; the potential of mean
force is also decomposed into its entropic and enthalpic contributions. Mode
coupling theory is employed to compute self-diffusion coefficient of water, as
well as diffusion coefficient of a dilute hydrophobic solute; good agreement
with molecular dynamics simulation results is found
Scalar multi-wormholes
In 1921 Bach and Weyl derived the method of superposition to construct new
axially symmetric vacuum solutions of General Relativity. In this paper we
extend the Bach-Weyl approach to non-vacuum configurations with massless scalar
fields. Considering a phantom scalar field with the negative kinetic energy, we
construct a multi-wormhole solution describing an axially symmetric
superposition of wormholes. The solution found is static, everywhere
regular and has no event horizons. These features drastically tell the
multi-wormhole configuration from other axially symmetric vacuum solutions
which inevitably contain gravitationally inert singular structures, such as
`struts' and `membranes', that keep the two bodies apart making a stable
configuration. However, the multi-wormholes are static without any singular
struts. Instead, the stationarity of the multi-wormhole configuration is
provided by the phantom scalar field with the negative kinetic energy. Anther
unusual property is that the multi-wormhole spacetime has a complicated
topological structure. Namely, in the spacetime there exist
asymptotically flat regions connected by throats.Comment: 11 pages, 13 figure
The eddy heat-flux in rotating turbulent convection
The three components of the heat-flux vector F_\thetaF_r
which for \emph{free} turbulence is also believed to peak at the poles (see Eq.
(19) below). As we can show, however, the consequences of this unexpected
result (also obtained by Kaepylae, Korpi and Tuominen 2004) for the theory of
differential rotation are small as mainly the F_\thetaF_\phiF_\phi$ is closely related to the radial
\Lambda-effect which is known to be also negative in stratified and rapidly
rotating convection zones.Comment: 8 pages, 9 figures, Astron. Astrophys. (subm.
Structural and Dynamical Anomalies of a Gaussian Core Fluid: a Mode Coupling Theory Study
We present a theoretical study of transport properties of a liquid comprised
of particles uist1:/home/sokrates/egorov/oldhome/Pap41/Submit > m abs.tex We
present a theoretical study of transport properties of a liquid comprised of
particles interacting via Gaussian Core pair potential. Shear viscosity and
self-diffusion coefficient are computed on the basis of the mode-coupling
theory, with required structural input obtained from integral equation theory.
Both self-diffusion coefficient and viscosity display anomalous density
dependence, with diffusivity increasing and viscosity decreasing with density
within a particular density range along several isotherms below a certain
temperature. Our theoretical results for both transport coefficients are in
good agreement with the simulation data
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