16,634 research outputs found
From Microscales to Macroscales in 3D: Selfconsistent Equation of State for Supernova and Neutron Star Models
First results from a fully self-consistent, temperature-dependent equation of
state that spans the whole density range of neutron stars and supernova cores
are presented. The equation of state (EoS) is calculated using a mean-field
Hartree-Fock method in three dimensions (3D). The nuclear interaction is
represented by the phenomenological Skyrme model in this work, but the EoS can
be obtained in our framework for any suitable form of the nucleon-nucleon
effective interaction. The scheme we employ naturally allows effects such as
(i) neutron drip, which results in an external neutron gas, (ii) the variety of
exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii)
the subsequent dissolution of these nuclei into nuclear matter. In this way,
the equation of state is calculated across phase transitions without recourse
to interpolation techniques between density regimes described by different
physical models. EoS tables are calculated in the wide range of densities,
temperature and proton/neutron ratios on the ORNL NCCS XT3, using up to 2000
processors simultaneously.Comment: 6 pages, 11 figures. Published in conference proceedings Journal of
Physics: Conference Series 46 (2006) 408. Extended version to be submitted to
Phys. Rev.
Nilsson diagrams for light neutron-rich nuclei with weakly-bound neutrons
Using Woods-Saxon potentials and the eigenphase formalism for one-particle
resonances, one-particle bound and resonant levels for neutrons as a function
of quadrupole deformation are presented, which are supposed to be useful for
the interpretation of spectroscopic properties of some light neutron-rich
nuclei with weakly-bound neutrons. Compared with Nilsson diagrams in text books
which are constructed using modified oscillator potentials, we point out a
systematic change of the shell structure in connection with both weakly-bound
and resonant one-particle levels related to small orbital angular momenta
. Then, it is seen that weakly-bound neutrons in nuclei such as
C and Mg may prefer to being deformed as a result of
Jahn-Teller effect, due to the near degeneracy of the 1d-2s
levels and the 1f-2p levels in the spherical potential,
respectively. Furthermore, the absence of some one-particle resonant levels
compared with the Nilsson diagrams in text books is illustrated.Comment: 12 pages, 5 figure
Levinson's Theorem for Non-local Interactions in Two Dimensions
In the light of the Sturm-Liouville theorem, the Levinson theorem for the
Schr\"{o}dinger equation with both local and non-local cylindrically symmetric
potentials is studied. It is proved that the two-dimensional Levinson theorem
holds for the case with both local and non-local cylindrically symmetric cutoff
potentials, which is not necessarily separable. In addition, the problems
related to the positive-energy bound states and the physically redundant state
are also discussed in this paper.Comment: Latex 11 pages, no figure, submitted to J. Phys. A Email:
[email protected], [email protected]
London, UK
This chapter reports the results of a survey on sexual transit crime with 109 respondents. An analysis of the types of sexual harassment experienced by students found that 70 respondents (59 %) reported experiencing some form of sexual harassment at least once in the last three years, either walking to, waiting for, or on board some mode of transport. In total only five students said that they had reported experiences of sexual harassment on transit, and 17 said they had not. These small numbers do not allow a more detailed exploration. Overall, 30% of respondents reported rarely or never feeling safe when either using or waiting for the bus either during the day or after dark, compared to 18% who reported the same for the train or tram. The main precautionary responses identified across both bus and rail were avoiding carrying purses or wallets, and traveling only during daytime. The chapter briefly summarizes the main findings from the case study and makes suggestions for research and practice
Ice/frost detection using millimeter wave radiometry
A series of ice detection tests was performed on the shuttle external tank (ET) and on ET target samples using a 35/95 GHz instrumentation radiometer. Ice was formed using liquid nitrogen and water spray inside a test enclosure containing ET spray on foam insulation samples. During cryogenic fueling operations prior to the shuttle orbiter engine firing tests, ice was formed with freon and water over a one meter square section of the ET LOX tank. Data analysis was performed on the ice signatures, collected by the radiometer, using Georgia Tech computing facilities. Data analysis technique developed include: ice signature images of scanned ET target; pixel temperature contour plots; time correlation of target data with ice present versus no ice formation; and ice signature radiometric temperature statistical data, i.e., mean, variance, and standard deviation
Data on Apollo 11 and 12 samples. Speculations on petrologic differentiation Final report
Petrologic and mineralogic studies of Apollo 11 and 12 lunar rock
On the number of particles which a curved quantum waveguide can bind
We discuss the discrete spectrum of N particles in a curved planar waveguide.
If they are neutral fermions, the maximum number of particles which the
waveguide can bind is given by a one-particle Birman-Schwinger bound in
combination with the Pauli principle. On the other hand, if they are charged,
e.g., electrons in a bent quantum wire, the Coulomb repulsion plays a crucial
role. We prove a sufficient condition under which the discrete spectrum of such
a system is empty.Comment: a LateX file, 12 page
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