27,385 research outputs found
Nambu brackets with constraint functionals
If a Hamiltonian dynamical system with degrees of freedom admits
constants of motion more than , then there exist some functional
relations between the constants of motion. Among these relations the number of
functionally independent ones are . It is shown that for such a
system in which the constants of motion constitute a polynomial algebra closing
in Poisson bracket, the Nambu brackets can be written in terms of these
constraint functionals. The exemplification is very rich and several of them
are analyzed in the text.Comment: 15 page
Development of a severe local storm prediction system: A 60-day test of a mesoscale primitive equation model
The progress and problems associated with the dynamical forecast system which was developed to predict severe storms are examined. The meteorological problem of severe convective storm forecasting is reviewed. The cascade hypothesis which forms the theoretical core of the nested grid dynamical numerical modelling system is described. The dynamical and numerical structure of the model used during the 1978 test period is presented and a preliminary description of a proposed multigrid system for future experiments and tests is provided. Six cases from the spring of 1978 are discussed to illustrate the model's performance and its problems. Potential solutions to the problems are examined
Eigenstate Structure in Graphs and Disordered Lattices
We study wave function structure for quantum graphs in the chaotic and
disordered regime, using measures such as the wave function intensity
distribution and the inverse participation ratio. The result is much less
ergodicity than expected from random matrix theory, even though the spectral
statistics are in agreement with random matrix predictions. Instead, analytical
calculations based on short-time semiclassical behavior correctly describe the
eigenstate structure.Comment: 4 pages, including 2 figure
CPA elderCare/primePlus services : a practitioner\u27s resource guide;
CD-ROM files converted to PDF and included after main texthttps://egrove.olemiss.edu/aicpa_guides/1105/thumbnail.jp
Nitrous oxide in fresh water systems: An estimate for the yield of atmospheric N2O associated with disposal of human waste
The N2O content of waters in the Potomac and Merrimack Rivers was measured on a number of occasions over the period April to July 1977. The concentrations of dissolved N2O exceeded those which would apply in equilibrium with air by factors ranging from about 46 in the Potomac to 1.2 in the Merrimack. Highest concentrations of dissolved N2O were associated with sewage discharges from the vicinity of Washington, D. C., and analysis indicates a relatively high yield, 1.3 to 11%, for prompt conversion of waste nitrogen to N2O. Measurements of dissolved N2O in fresh water ponds near Boston demonstrated that aquatic systems provide both strong sources and sinks for atmospheric N2O
On Toroidal Horizons in Binary Black Hole Inspirals
We examine the structure of the event horizon for numerical simulations of
two black holes that begin in a quasicircular orbit, inspiral, and finally
merge. We find that the spatial cross section of the merged event horizon has
spherical topology (to the limit of our resolution), despite the expectation
that generic binary black hole mergers in the absence of symmetries should
result in an event horizon that briefly has a toroidal cross section. Using
insight gained from our numerical simulations, we investigate how the choice of
time slicing affects both the spatial cross section of the event horizon and
the locus of points at which generators of the event horizon cross. To ensure
the robustness of our conclusions, our results are checked at multiple
numerical resolutions. 3D visualization data for these resolutions are
available for public access online. We find that the structure of the horizon
generators in our simulations is consistent with expectations, and the lack of
toroidal horizons in our simulations is due to our choice of time slicing.Comment: Submitted to Phys. Rev.
Localization of Eigenfunctions in the Stadium Billiard
We present a systematic survey of scarring and symmetry effects in the
stadium billiard. The localization of individual eigenfunctions in Husimi phase
space is studied first, and it is demonstrated that on average there is more
localization than can be accounted for on the basis of random-matrix theory,
even after removal of bouncing-ball states and visible scars. A major point of
the paper is that symmetry considerations, including parity and time-reversal
symmetries, enter to influence the total amount of localization. The properties
of the local density of states spectrum are also investigated, as a function of
phase space location. Aside from the bouncing-ball region of phase space,
excess localization of the spectrum is found on short periodic orbits and along
certain symmetry-related lines; the origin of all these sources of localization
is discussed quantitatively and comparison is made with analytical predictions.
Scarring is observed to be present in all the energy ranges considered. In
light of these results the excess localization in individual eigenstates is
interpreted as being primarily due to symmetry effects; another source of
excess localization, scarring by multiple unstable periodic orbits, is smaller
by a factor of .Comment: 31 pages, including 10 figure
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