22,444 research outputs found
Drived diffusion of vector fields
A model for the diffusion of vector fields driven by external forces is
proposed. Using the renormalization group and the -expansion, the
dynamical critical properties of the model with gaussian noise for dimensions
below the critical dimension are investigated and new transport universality
classes are obtained.Comment: 11 pages, title changed, anisotropic diffusion further discussed and
emphasize
Boundary K-matrices for the XYZ, XXZ AND XXX spin chains
The general solutions for the factorization equations of the reflection
matrices for the eight vertex and six vertex models (XYZ, XXZ
and XXX chains) are found. The associated integrable magnetic Hamiltonians are
explicitly derived, finding families dependig on several continuous as well as
discrete parameters.Comment: 13 page
Possible effect of dietary phytase supplementation on broiler sodium requirement.
Projeto/Plano de Ação: 11.11.11.111
Turbulence generation by a shock wave interacting with a random density inhomogeneity field
When a planar shock wave interacts with a random pattern of pre-shock density
non-uniformities, it generates an anisotropic turbulent velocity/vorticity
field. This turbulence plays an important role at the early stages of the
mixing process in the compressed fluid. This situation emerges naturally in
shock interaction with weakly inhomogeneous deuterium-wicked foam targets in
Inertial Confinement Fusion (ICF) and with density clumps/clouds in
astrophysics. We present an exact small-amplitude linear theory describing such
interaction. It is based on the exact theory of time and space evolution of the
perturbed quantities behind a corrugated shock front for a single-mode
pre-shock non-uniformity. Appropriate mode averaging in 2D results in closed
analytical expressions for the turbulent kinetic energy, degree of anisotropy
of velocity and vorticity fields in the shocked fluid, shock amplification of
the density non-uniformity, and sonic energy flux radiated downstream. These
explicit formulas are further simplified in the important asymptotic limits of
weak/strong shocks and highly compressible fluids. A comparison with the
related problem of a shock interacting with a pre-shock isotropic vorticity
field is also presented.Comment: This article corresponds to a presentation given at the Second
International Conference and Advanced School "Turbulent Mixing and Beyond,"
held on 27 July - 07 August 2009 at the Abdus Salam International Centre for
Theoretical Physics, Trieste, Italy. That Conference Proceeding will be
published as a Topical Issue of the Physica Scripta IOP scienc
Dietary enzyme supplementation on broiler performance from 1 up to 42 days of age.
Projeto/Plano de Ação: 11.11.11.111
Automatic selection of color channels for segmentation of aerial images with photometric variations.
Decay-assisted collinear resonance ionization spectroscopy: Application to neutron-deficient francium
This paper reports on the hyperfine-structure and radioactive-decay studies
of the neutron-deficient francium isotopes Fr performed with the
Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE
facility, CERN. The high resolution innate to collinear laser spectroscopy is
combined with the high efficiency of ion detection to provide a
highly-sensitive technique to probe the hyperfine structure of exotic isotopes.
The technique of decay-assisted laser spectroscopy is presented, whereby the
isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay
tagging of the hyperfine components. Here, we present the first
hyperfine-structure measurements of the neutron-deficient francium isotopes
Fr, in addition to the identification of the low-lying states of
Fr performed at the CRIS experiment.Comment: Accepted for publication with Physical Review
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