5,399 research outputs found
Irrational mode locking in quasiperiodic systems
A model for ac-driven systems, based on the
Tang-Wiesenfeld-Bak-Coppersmith-Littlewood automaton for an elastic medium,
exhibits mode-locked steps with frequencies that are irrational multiples of
the drive frequency, when the pinning is spatially quasiperiodic. Detailed
numerical evidence is presented for the large-system-size convergence of such a
mode-locked step. The irrational mode locking is stable to small thermal noise
and weak disorder. Continuous time models with irrational mode locking and
possible experimental realizations are discussed.Comment: 4 pages, 3 figures, 1 table; revision: 2 figures modified, reference
added, minor clarification
The Effect of Mining Out Coal No. 6 Before Taking Out the Seams Above it
Item includes a discussion between A. Roy, J. L. Morris, T. Bancroft, A. Howells, E. McMillin and W. Dalrymple of Thomas Middleton's pape
Results of aircraft open-loop tests of an experimental magnetic leader cable system for guidance during roll-out and turnoff
An experimental magnetic leader cable (MLC) system designed to measure aircraft lateral displacement from centerline and heading relative to centerline during rollout, turnoff, and taxi was tested at NASA's Wallops Flight Facility using NASA's Transport System Research Vehicle (TSRV), a modified B-737. The MLC system consisted of ground equipment that produced a magnetic field about a wire along runway centerline and airborne equipment that detected the strength and direction of this field and computed displacement and heading. Results of these tests indicate that estimates of aircraft displacement from centerline produced by the magnetic leader cable system using either of the two algorithms appear to be adequate for use by an automatic control system during rollout, turnoff, and taxi. Estimates of heading, however, are not sufficiently accurate for use, probably because of distortion of the magnetic field by the metal aircraft
Phantastes Chapter 24: The Honest Whore
Thomas Dekker (1572-1632) was a dramatist and writer of popular pamphlets describing London life. This line comes from the play The Honest Whore, Part II (1605 or 1606). The Honest Whore, Part I, a collaboration between Dekker and Thomas Middleton, was performed in 1604
Persistence and Memory in Patchwork Dynamics for Glassy Models
Slow dynamics in disordered materials prohibits direct simulation of their
rich nonequilibrium behavior at large scales. "Patchwork dynamics" is
introduced to mimic relaxation over a very broad range of time scales by
equilibrating or optimizing directly on successive length scales. This dynamics
is used to study coarsening and to replicate memory effects for spin glasses
and random ferromagnets. It is also used to find, with high confidence, exact
ground states in large or toroidal samples.Comment: 4 pages, 4 figures; reference correctio
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