9,922 research outputs found
Constraints on Dimensional Warped Spaces
In order to investigate the phenomenological implications of allowing gauge
fields to propagate in warped spaces of more than five dimensions, we consider
a toy model of a space warped by the presence of a anisotropic bulk
cosmological constant. After solving the Einstein equation, three classes of
solutions are found, those in which the additional () dimensions are
growing, shrinking or remaining constant. It is found that gauge fields
propagating in these spaces have a significantly different Kaluza Klein (KK)
mass spectrum and couplings from that of the Randall and Sundrum model. This
leads to a greatly reduced lower bound on the KK scale, arising from
electroweak constraints, for spaces growing towards the IR brane.Comment: 6 pages, 5 figures PASCOS2010 International Symposium proceedin
Improved analytic longitudinal response analysis for axisymmetric launch vehicles. Volume I - Linear analytic model
Improved analytic longitudinal response analysis for axisymmetric launch vehicles - linear mode
New genus of primitive wombat (Vombatidae, Marsupialia) from Miocene deposits in the Riversleigh World Heritage Area (Queensland, Australia)
Copyright Palaeontological Association, March 2015.
This is an open access article, available to all readers online, published under a creative commons licensing (https://creativecommons.org/licenses/by/4.0/)
Solvent fluctuations around solvophobic, solvophilic and patchy nanostructures and the accompanying solvent mediated interactions
Using classical density functional theory (DFT) we calculate the density
profile and local compressibility of a
simple liquid solvent in which a pair of blocks with (microscopic) rectangular
cross-section are immersed. We consider blocks that are solvophobic,
solvophilic and also ones that have both solvophobic and solvophilic patches.
Large values of correspond to regions in space where the
liquid density is fluctuating most strongly. We seek to elucidate how enhanced
density fluctuations correlate with the solvent mediated force between the
blocks, as the distance between the blocks and the chemical potential of the
liquid reservoir vary. For sufficiently solvophobic blocks, at small block
separations and small deviations from bulk gas-liquid coexistence, we observe a
strongly attractive (near constant) force, stemming from capillary evaporation
to form a low density gas-like intrusion between the blocks. The accompanying
exhibits structure which reflects the incipient gas-liquid
interfaces that develop. We argue that our model system provides a means to
understanding the basic physics of solvent mediated interactions between
nanostructures, and between objects such as proteins in water, that possess
hydrophobic and hydrophilic patches.Comment: 19 pages, 21 figure
Asymptotic decay of pair correlations in a Yukawa fluid
We analyse the asymptotic decay of the total correlation
function, , for a fluid composed of particles interacting via a (point)
Yukawa pair potential. Such a potential provides a simple model for dusty
plasmas. The asymptotic decay is determined by the poles of the liquid
structure factor in the complex plane. We use the hypernetted-chain closure to
the Ornstein-Zernike equation to determine the line in the phase diagram,
well-removed from the freezing transition line, where crossover occurs in the
ultimate decay of , from monotonic to damped oscillatory. We show: i)
crossover takes place via the same mechanism (coalescence of imaginary poles)
as in the classical one-component plasma and in other models of Coulomb fluids
and ii) leading-order pole contributions provide an accurate description of
at intermediate distances as well as at long range.Comment: 5 pages, 3 figure
Relationship between Local Molecular Field Theory and Density Functional Theory for non-uniform liquids
The Local Molecular Field Theory (LMF) developed by Weeks and co-workers has
proved successful for treating the structure and thermodynamics of a variety of
non-uniform liquids. By reformulating LMF in terms of one-body direct
correlation functions we recast the theory in the framework of classical
Density Functional Theory (DFT). We show that the general LMF equation for the
effective reference potential phi_R follows directly from the standard
mean-field DFT treatment of attractive interatomic forces. Using an accurate
(Fundamental Measures) DFT for the non-uniform hard-sphere reference fluid we
determine phi_R for a hard-core Yukawa liquid adsorbed at a planar hard wall.
In the approach to bulk liquid-gas coexistence we find the effective potentials
exhibit rich structure that can include damped oscillations at large distances
from the wall as well as the repulsive hump near the wall required to generate
the low density 'gas' layer characteristic of complete drying. We argue that it
would be difficult to obtain the same level of detail from other (non DFT
based) implementations of LMF. LMF emphasizes the importance of making an
intelligent division of the interatomic pair potential of the full system into
a reference part and a remainder that can be treated in mean-field
approximation. We investigate different divisions for an exactly solvable one-
dimensional model where the pair potential has a hard-core plus a linear
attractive tail. Results for the structure factor and the equation of state of
the uniform fluid show that including a significant portion of the attraction
in the reference system can be much more accurate than treating the full
attractive tail in mean-field approximation. We discuss further aspects of the
relationship between LMF and DFT.Comment: 35 pages, 10 Fig
In re Review of examinations of the Virginia State Board of Accountancy, October 26-28, 1925
Letter inserted into the Library\u27s copy of the 1925 Examination by the Virginia State Board of Accountancy
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