138 research outputs found
From energy-density functionals to mean field potentials: a systematic derivation
In this paper we present a systematic method to solve the variational problem
of the derivation of a self-consistent Kohn-Sham field from an arbitrary local
energy functional. We illustrate this formalism with an application in nuclear
physics and give the general mean field associated to the widely used Skyrme
effective interaction
From multifragmentation to supernovae and neutron stars
The thermodynamics properties of globally neutral dense stellar matter are
analyzed both in terms of mean field instabilities and structures beyond the
mean field. The mean field response to finite wavelenght fluctuations is
calculated with the realistic Sly230a effective interaction. A Monte Carlo
simulation of a schematic lattice Hamiltonian shows the importance of
calculations beyond the mean field to calculate the phase diagram of stellar
matter. The analogies and differences respect to the thermodynamics of nuclear
matter and finite nuclei are stressed.Comment: To be published in Acta Phys. Hung.
Fermionic Molecular Dynamics for nuclear dynamics and thermodynamics
A new Fermionic Molecular Dynamics (FMD) model based on a Skyrme functional
is proposed in this paper. After introducing the basic formalism, some first
applications to nuclear structure and nuclear thermodynamics are presentedComment: 5 pages, Proceedings of the French-Japanese Symposium, September
2008. To be published in Int. J. of Mod. Phys.
Ising analogue to compact-star matter
By constructing an Ising analogue of compact-star matter at sub-saturation
density we explored the effect of Coulomb frustration on the nuclear liquid-gas
phase transition. Our conclusions is twofold. First, the range of temperatures
where inhomogeneous phases form expands with increasing Coulomb-field strength.
Second, within the approximation of uniform electron distribution, the limiting
point upon which the phase-coexistence region ends does not exhibit any
critical behaviour. Possible astrophysics consequences and thermodynamical
connections are discussed.Comment: 4 pages, 3 figure
Crack Detectability in Vertical Axis Cooling Pumps During Operation
The problem which is faced in this paper is the analysis of the effects of a transverse propagating crack on the vibrational behaviour of a vertical axis cooling pump. The crack is assumed to develop in a section between the impeller and a seal, which prevents the hot water to flow upwards along the rotor shaft. The pressurized seal is fed with an injection of cold water. Crack initiation may be due to a thermal striping phenomenon. Afterwards, crack growth could be driven by a combination of thermal and mechanical loads, causing alternate cyclic stress in the shaft. Cracking instances of this type have been reported worldwide in several machines of similar design. In this paper, the fact is emphasized that the crack behavior is likely to be influenced by the thermal field and by the water pressure in the cracked area. A dynamical lineshaft model, integrated by an original representation of the crack, has been developed to investigate the possible vibratory symptoms related to a crack propagation. The vibrations are generally measured in correspondence of a rigid coupling which connects the motor shaft to the pump shaft, in position which is rather far away from crack. 1x rev., 2x rev and 3x rev. vibration components, which are generally displayed by the machine condition monitoring system and are the most significative symptoms of the presence of a transverse crack in a rotating shaft, are calculated
Correlation anatomo-scannographique dans le cancer du larynx
Introduction : Le but de la chirurgie du larynx est de conserver dans la mesure du possible un larynx fonctionnel tout en répondant aux impératifs carcinologiques. Les limites d'extension tumorale doivent être finement analysées en pré-opératoire pour adopter la technique opératoire appropriée. dans ce domaine, l'apport de la TdM est incontestable pour l'étude de cette extension en profondeur.Patients et méthodes : il s'agit d'une étude rétrospective des dossiers de 43 patients explorés et traités respectivement aux services d'imagerie médicale et d'ORL de l'hôpital Tahar Sfar de Mahdia sur une période de 14 ans entre Janvier 1995 et décembre 2008.Résultats : La classification pré-opératoire des tumeurs pharyngo-laryngées est plus fiable en se basant à la fois sur l’endoscopie et la TdM que sur l’endoscopie seule. La fiabilité de cette association était de 76%. L'étude de certaines zones dites d'intérêt a montré une efficacité de 72% pour l'atteinte de la commissure antérieure, de 79% pour les bandes ventriculaires, de 81% pour la sous glotte, de 88% pour la loge HTE, de 83% pour les espaces para-glottiques et de 79% pour les cartilages. Nos résultats étaient concordants à ceux de la littérature.Discussion et conclusion : la TdM constitue une partie intégrante du bilan préopératoire des cancers du pharyngolarynx. Elle précise l'extension tumorale en profondeur aux espaces graisseux, aux cartilages et aux tissus extralaryngés. L’analyse fine des images tomodensitométriques permet donc d’orienter la décision thérapeutique.Mots clés : cancer, larynx, anatomopathologie, chirurgie
Wigner-Seitz cells in neutron star crust with finite range interactions
The structure of Wigner-Seitz cells in the inner crust of neutron stars is
investigated using a microcospic Hartree-Fock-BCS approach with finite range
D1S and M3Y-P4 interactions. Large effects on the densities are found compared
to previous predictions using Skyrme interactions. Pairing effects are found to
be small, and they are attenuated by the use of finite range interactions in
the mean field.Comment: 11 pages, 5 figure
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