34,140 research outputs found
Seismology of adolescent neutron stars: Accounting for thermal effects and crust elasticity
We study the oscillations of relativistic stars, incorporating key physics
associated with internal composition, thermal gradients and crust elasticity.
Our aim is to develop a formalism which is able to account for the
state-of-the-art understanding of the complex physics associated with these
systems. As a first step, we build models using a modern equation of state
including composition gradients and density discontinuities associated with
internal phase-transitions (like the crust-core transition and the point where
muons first appear in the core). In order to understand the nature of the
oscillation spectrum, we carry out cooling simulations to provide realistic
snapshots of the temperature distribution in the interior as the star evolves
through adolescence. The associated thermal pressure is incorporated in the
perturbation analysis, and we discuss the presence of -modes arising as a
result of thermal effects. We also consider interface modes due to
phase-transitions and the gradual formation of the star's crust and the
emergence of a set of shear modes.Comment: 27 pages, 14 figure
Retrospective study of more than 9000 feline cutaneous tumours in the UK: 2006–2013
The aim of the study was to utilise a large database available from a UK-based, commercial veterinary diagnostic laboratory to ascertain the prevalence of different forms of cutaneous neoplasia within the feline population, and to detect any breed, sex or age predilections for the more common tumours
Existence of Long-Range Order for Trapped Interacting Bosons
We derive an inequality governing ``long range'' order for a localized
Bose-condensed state, relating the condensate fraction at a given temperature
with effective curvature radius of the condensate and total particle number.
For the specific example of a one-dimensional, harmonically trapped dilute Bose
condensate, it is shown that the inequality gives an explicit upper bound for
the Thomas-Fermi condensate size which may be tested in current experiments.Comment: 4 pages, 1 figure, RevTex4. Title changed at the request of editors;
to appear in Phys. Rev. Letter
Determination of a set of constitutive equations for an al-li alloy at SPF conditions
© 2015 The Authors.Uniaxial tensile tests of aluminium-lithium alloy AA1420wereconducted at superplastic forming conditions. The mechanical properties of this Al-Li alloy were then modelled by a set of physicallybased constitutive equations. The constitutive equations describe the isotropic work hardening,recovery and damage by dislocation density changes and grain size evolution. Based on a recent upgraded optimisation technique, the material constants for these constitutive equations were determined
Noncommutative D-Brane in Non-Constant NS-NS B Field Background
We show that when the field strength H of the NS-NS B field does not vanish,
the coordinates X and momenta P of an open string endpoints satisfy a set of
mixed commutation relations among themselves. Identifying X and P with the
coordinates and derivatives of the D-brane world volume, we find a new type of
noncommutative spaces which is very different from those associated with a
constant B field background.Comment: 11 pages, Latex, minor modification
The role of electron-electron interactions in two-dimensional Dirac fermions
The role of electron-electron interactions on two-dimensional Dirac fermions
remains enigmatic. Using a combination of nonperturbative numerical and
analytical techniques that incorporate both the contact and long-range parts of
the Coulomb interaction, we identify the two previously discussed regimes: a
Gross-Neveu transition to a strongly correlated Mott insulator, and a
semi-metallic state with a logarithmically diverging Fermi velocity accurately
described by the random phase approximation. Most interestingly, experimental
realizations of Dirac fermions span the crossover between these two regimes
providing the physical mechanism that masks this velocity divergence. We
explain several long-standing mysteries including why the observed Fermi
velocity in graphene is consistently about 20 percent larger than the best
values calculated using ab initio and why graphene on different substrates show
different behavior.Comment: 11 pages, 4 figure
Duality of Quasilocal Black Hole Thermodynamics
We consider T-duality of the quasilocal black hole thermodynamics for the
three-dimensional low energy effective string theory. Quasilocal thermodynamic
variables in the first law are explicitly calculated on a general axisymmetric
three-dimensional black hole solution and corresponding dual one. Physical
meaning of the dual invariance of the black hole entropy is considered in terms
of the Euclidean path integral formulation.Comment: 19 pages, Latex, no figures, to be published in Class. Quantum Grav.
Some minor changes, references adde
Scaling Theory of Polyelectrolyte Adsorption on Repulsive Charged Surface
We studied polyelectrolyte adsorption on a repulsive charged surface by
scaling analysis. At low ionic strength and low surface charge density in which
a single polyelectrolyte is able to be adsorbed onto the surface, different
regimes in the phase diagram are identified. The possibility of multi-layer
structure formed by polyelectrolytes of like charge is also investigated.Comment: 4 pages, 2 figure
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