46,495 research outputs found
Self-healing fuse
Fast-acting current limiting device provides current overload protection for vulnerable circuit elements and then re-establishes conduction path within milliseconds. Fuse can also perform as fast-acting switch to clear transient circuit overloads. Fuse takes advantage of large increase in electrical resistivity that occurs when liquid metal vaporizes
Gravitationally enhanced depolarization of ultracold neutrons in magnetic-field gradients
Trapped ultracold neutrons (UCN) have for many years been the mainstay of experiments to search for the electric dipole moment (EDM) of the neutron, a critical parameter in constraining scenarios of new physics beyond the Standard Model. Because their energies are so low, UCN preferentially populate the lower region of their physical enclosure, and do not sample uniformly the ambient magnetic field throughout the storage volume. This leads to a substantial increase in the rate of depolarization, as well as to shifts in the measured frequency of the stored neutrons. Consequences for EDM measurements are discussed
Self-healing fuse development
The mercury-filled self-healing fuses developed for this program afford very good protection from circuit faults with rapid reclosure. Fuse performance and design parameters have been characterized. Life tests indicate a capability of 500 fuse operations. Fuse ratings are 150 v at 5, 15, 25 and 50 circuit A. A series of sample fuses using alumina and beryllia insulation have been furnished to NASA for circuit evaluation
Space - Single Precision Cowell Trajectory Program
Single Precision Cowell Trajectory program - digital computer program for trajectory computatio
SFPRO - Single Precision Cowell Trajectory Processor
Digital computer program for IBM 7094 computer to generate spacecraft tracking station calculation
The Nernst effect in high- superconductors
The observation of a large Nernst signal in an extended region above
the critical temperature in hole-doped cuprates provides evidence that
vortex excitations survive above . The results support the scenario that
superfluidity vanishes because long-range phase coherence is destroyed by
thermally-created vortices (in zero field), and that the pair condensate
extends high into the pseudogap state in the underdoped (UD) regime. We present
a series of measurements to high fields which provide strong evidence for
this phase-disordering scenario.Comment: 21 pages, 28 figure
Reducing the Effects of Unequal Number of Games on Rankings
Ranking is an important mathematical process in a variety of contexts such as information retrieval, sports and business. Sports ranking methods can be applied both in and beyond the context of athletics. In both settings, once the concept of a game has been defined, teams (or individuals) accumulate wins, losses, and ties, which are then factored into the ranking computation. Many settings involve an unequal number of games between competitors. This paper demonstrates how to adapt two sports rankings methods, the Colley and Massey ranking methods, to settings where an unequal number of games are played between the teams. In such settings, the standard derivations of the methods can produce nonsensical rankings. This paper introduces the idea of including a super-user into the rankings and considers the effect of this fictitious player on the ratings. We apply such techniques to rank batters and pitchers in Major League baseball, professional tennis players, and participants in a free online social game. The ideas introduced in this paper can further the scope that such methods are applied and the depth of insight they offer
Dipolar Interactions and Origin of Spin Ice in Ising Pyrochlore Magnets
Recent experiments suggest that the Ising pyrochlore magnets and display qualitative
properties of the spin ice model proposed by Harris {\it et al.} \prl {\bf 79},
2554 (1997). We discuss the dipolar energy scale present in both these
materials and consider how they can display spin ice behavior {\it despite} the
presence of long range interactions. Specifically, we present numerical
simulations and a mean field analysis of pyrochlore Ising systems in the
presence of nearest neighbor exchange and long range dipolar interactions. We
find that two possible phases can occur, a long range ordered antiferromagnetic
one and the other dominated by spin ice features. Our quantitative theory is in
very good agreement with experimental data on both
and . We suggest that the nearest neighbor exchange in
is {\it antiferromagnetic} and that spin ice behavior
is induced by long range dipolar interactions.Comment: 4 postscript figures included. Submitted to Physical Review Letters
Contact: [email protected]
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