48,208 research outputs found
Graphics and composite material computer program enhancements for SPAR
User documentation is provided for additional computer programs developed for use in conjunction with SPAR. These programs plot digital data, simplify input for composite material section properties, and compute lamina stresses and strains. Sample problems are presented including execution procedures, program input, and graphical output
Ignition of binary alloys of uranium
Experiments determine the effect of alloying additives on the ignition of uranium. Data on oxidation rates, ignition temperatures, and burning curves are provided in the report
Stable divisorial gonality is in NP
Divisorial gonality and stable divisorial gonality are graph parameters,
which have an origin in algebraic geometry. Divisorial gonality of a connected
graph can be defined with help of a chip firing game on . The stable
divisorial gonality of is the minimum divisorial gonality over all
subdivisions of edges of .
In this paper we prove that deciding whether a given connected graph has
stable divisorial gonality at most a given integer belongs to the class NP.
Combined with the result that (stable) divisorial gonality is NP-hard by
Gijswijt, we obtain that stable divisorial gonality is NP-complete. The proof
consist of a partial certificate that can be verified by solving an Integer
Linear Programming instance. As a corollary, we have that the number of
subdivisions needed for minimum stable divisorial gonality of a graph with
vertices is bounded by for a polynomial
Towards understanding Regge trajectories in holographic QCD
We reassess a work done by Migdal on the spectrum of low-energy vector mesons
in QCD in the light of the AdS-QCD correspondence. Recently, a tantalizing
parallelism was suggested between Migdal's work and a family of holographic
duals of QCD. Despite the intriguing similarities, both approaches face a major
drawback: the spectrum is in conflict with well-tested Regge scaling. However,
it has recently been shown that holographic duals can be modified to accomodate
Regge behavior. Therefore, it is interesting to understand whether Regge
behavior can also be achieved in Migdal's approach. In this paper we
investigate this issue. We find that Migdal's approach, which is based on a
modified Pade approximant, is closely related to the issue of quark-hadron
duality breakdown in QCD.Comment: 17 pages, 1 figure. Typos fixed, references added, improved
discussion. Minor changes to match the journal versio
Comment on ``Intermittent Synchronization in a Pair of Coupled Chaotic Pendula"
The main aim of this comment is to emphasize that the conditional Lyapunov
exponents play an important role in distinguishing between intermittent and
persistent synchronization, when the analytic criteria for asymptotic stability
are not uniformly obeyed.Comment: 2 pages, RevTeX 4, 1 EPS figur
MULTIPAC, a multiple pool processor and computer for a spacecraft central data system, phase 2 Final report
MULTIPAC, multiple pool processor and computer for deep space probe central data syste
Seeking for toroidal event horizons from initially stationary BH configurations
We construct and evolve non-rotating vacuum initial data with a ring
singularity, based on a simple extension of the standard Brill-Lindquist
multiple black-hole initial data, and search for event horizons with spatial
slices that are toroidal when the ring radius is sufficiently large. While
evolutions of the ring singularity are not numerically feasible for large
radii, we find some evidence, based on configurations of multiple BHs arranged
in a ring, that this configuration leads to singular limit where the horizon
width has zero size, possibly indicating the presence of a naked singularity,
when the radius of the ring is sufficiently large. This is in agreement with
previous studies that have found that there is no apparent horizon surrounding
the ring singularity when the ring's radius is larger than about twice its
mass.Comment: 24 pages, 14 figure
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