2,954 research outputs found
High-spin structures as the probes of proton-neutron pairing
Rotating nuclei in the mass region have been studied within
the framework of isovector mean field theory. Available data is well and
systematically described in the calculations. The present study supports the
presence of strong isovector pair field at low spin, which is, however,
destroyed at high spin. No clear evidence for the existence of the isoscalar
pairing has been found.Comment: Invited talk presented at the XIII Nuclear Physics Workshop,
Kazimierz Dolny, Sept. 27 - Oct. 1, Poland; submitted to International
Journal of Modern Physics
Analysis of the contributions of three-body potentials in the equation of state of 4He
The effect of three-body interatomic contributions in the equation of state
of 4He are investigated. A recent two-body potential together with the Cohen
and Murrell (Chem. Phys. Lett. 260, 371 (1996)) three-body potential are
applied to describe bulk helium. The triple-dipole dispersion and exchange
energies are evaluated subjected only to statistical uncertainties. An
extension of the diffusion Monte Carlo method is applied in order to compute
very small energies differences. The results show how the three-body
contributions affects the ground-state energy, the equilibrium, melting and
freezing densities.Comment: 18 pages, 3 figures, 4 table
Simulation of an 1857-like Mw 7.9 San Andreas Fault Earthquake and the Response of Tall Steel Moment Frame Buildings in Southern California â A Prototype Study
In 1857, an earthquake of magnitude 7.9 occurred on the San Andreas fault, starting at Parkfield and rupturing
in a southeasterly direction for more than 360 km. Such a unilateral rupture produces significant directivity
toward the San Fernando and Los Angeles basins. The strong shaking in the basins due to this earthquake
would have had significant long-period content (2-8 s), and the objective of this study is to quantify the impact
of such an earthquake on two 18-story steel moment frame building models, hypothetically located at 636 sites
on a 3.5 km grid in southern California. End-to-end simulations include modeling the source and rupture of a
fault at one end, numerically propagating the seismic waves through the earth structure, simulating the damage
to engineered structures and estimating the economic impact at the other end using high-performance computing.
In this prototype study, we use an inferred finite source model of the magnitude 7.9, 2002 Denali fault
earthquake in Alaska, and map it onto the San Andreas fault with the rupture originating at Parkfield and
propagating southward over a distance of 290 km. Using the spectral element seismic wave propagation code,
SPECFEM3D, we simulate an 1857-like earthquake on the San Andreas fault and compute ground motions at
the 636 analysis sites. Using the nonlinear structural analysis program, FRAME3D, we subsequently analyze
3-D structural models of an existing tall steel building designed using the 1982 Uniform Building Code (UBC),
as well as one designed according to the 1997 UBC, subjected to the computed ground motion at each of these
sites. We summarize the performance of these structural models on contour maps of peak interstory drift.
We then perform an economic loss analysis for the two buildings at each site, using the Matlab Damage and
Loss Analysis (MDLA) toolbox developed to implement the PEER loss-estimation methodology. The toolbox
includes damage prediction and repair cost estimation for structural and non-structural components and allows
for the computation of the mean and variance of building repair costs conditional on engineering demand
parameters (i.e. inter-story drift ratios and peak floor accelerations). Here, we modify it to treat steel-frame
high-rises, including aspects such as mechanical, electrical and plumbing systems, traction elevators, and the
possibility of irreparable structural damage. We then generate contour plots of conditional mean losses for the
San Fernando and the Los Angeles basins for the pre-Northridge and modern code-designed buildings, allowing
for comparison of the economic effects of the updated code for the scenario event. In principle, by simulating
multiple seismic events, consistent with the probabilistic seismic hazard for a building site, the same basic
approach could be used to quantify the uncertain losses from future earthquakes
Trademark: Compulsory Licensing as a Remedy for Violation of Section 5 of the Federal Trade Commission Act
In re Borden, Inc., FTC Dkt. No. 8978 (Aug. 19, 1976).
The interface of trademark and antitrust law has for some time generated controversy among various segments of the legal profession. The heart of the debate has centered on the need to harmonize the preservation of economic competition, which is the goal of the antitrust laws,\u27 with the entrepreneur\u27s interest in maintaining the undivided use of the mechanism by which his product or service is identified-his trademark. The achievement of harmony between these ends depends, therefore, upon a certain characterization of the trademark; that is, the particular social and economic functions which are attributed to trademarks must be examined in the light of the proscriptions of the antitrust laws. An appropriate focus for such a discourse is a case recently before the Federal Trade Commission (FTC), In re Borden, Inc. In-that case the administrative law judge, before whom the complaint was initially heard, ordered the respondent, Borden, to license its ReaLemon trademark to all others who wished to compete in the marketing and sale of reconstituted lemon juice, the trademark product. This remedy was thought necessary in order to disperse the monopoly power which Borden had been found to possess in that market, in violation of section 5 of the Federal Trade Commission Act
Shell Model Study of the Double Beta Decays of Ge, Se and Xe
The lifetimes for the double beta decays of Ge, Se and
Xe are calculated using very large shell model spaces. The two neutrino
matrix elements obtained are in good agreement with the present experimental
data. For eV we predict the following upper bounds to the
half-lives for the neutrinoless mode: , and . These results are the first from a new generation of Shell
Model calculations reaching O(10) dimensions
Global Calculations of Density Waves and Gap Formation in Protoplanetary Disks using a Moving Mesh
We calculate the global quasi-steady state of a thin disk perturbed by a
low-mass protoplanet orbiting at a fixed radius using extremely high-resolution
numerical integrations of Euler's equations in two dimensions. The calculations
are carried out using a moving computational domain, which greatly reduces
advection errors and allows for much longer time-steps than a fixed grid. We
calculate the angular momentum flux and the torque density as a function of
radius and compare them with analytical predictions. We discuss the
quasi-steady state after 100 orbits and the prospects for gap formation by low
mass planets.Comment: Accepted to Ap
Neutrino Opacities in Neutron Stars with Kaon Condensates
The neutrino mean free paths in hot neutron-star matter are obtained in the
presence of kaon condensates. The kaon-induced neutrino absorption process,
which is allowed only in the presence of kaon condensates, is considered for
both nondegenerate and degenerate neutrinos. The neutrino mean free path due to
this process is compared with that for the neutrino-nucleon scattering. While
the mean free path for the kaon-induced neutrino absorption process is shown to
be shorter than the ordinary two-nucleon absorption process by several orders
of magnitude when temperature is not very high, the neutrino-nucleon scattering
process has still a dominant contribution to the neutrino opacity. Thus, the
kaon-induced neutrino absorption process has a minor effect on the thermal and
dynamical evolution of protoneutron stars.Comment: 35 pages, 4 figure
Bubble generation in a twisted and bent DNA-like model
The DNA molecule is modeled by a parabola embedded chain with long-range
interactions between twisted base pair dipoles. A mechanism for bubble
generation is presented and investigated in two different configurations. Using
random normally distributed initial conditions to simulate thermal
fluctuations, a relationship between bubble generation, twist and curvature is
established. An analytical approach supports the numerical results.Comment: 7 pages, 8 figures. Accepted for Phys. Rev. E (in press
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