4,647 research outputs found
Null device for hand controller Patent
Manual control mechanism for adjusting control rod to null positio
Active rc networks of low sensitivity for integrated circuit transfer function
Active RC network is capable of extremely high Q performance with exceptional stability and has independently adjustable zeros and poles. The circuit consists of two integrators and two summers that are interconnected to produce a complete second-order numerator and a second-order denominator
Mini-Conference on Hamiltonian and Lagrangian Methods in Fluid and Plasma Physics
A mini-conference on Hamiltonian and Lagrangian methods in fluid and plasma
physics was held on November 14, 2002, as part of the 44th meeting of the
Division of Plasma Physics of the American Physical Society. This paper
summarizes the material presented during the talks scheduled during the
Mini-Conference, which was held to honor Allan Kaufman on the occasion of his
75th birthday.Comment: 14 pages, conference summar
Electromagnetic mirror drive system
Oscillatory electromagnetic mirror drive system for horizon scanner
MHD Turbulence Revisited
Kraichnan (1965) proposed that MHD turbulence occurs as a result of
collisions between oppositely directed Alfv\'en wave packets. Recent work has
generated some controversy over the nature of non linear couplings between
colliding Alfv\'en waves. We find that the resolution to much of the confusion
lies in the existence of a new type of turbulence, intermediate turbulence, in
which the cascade of energy in the inertial range exhibits properties
intermediate between those of weak and strong turbulent cascades. Some
properties of intermediate MHD turbulence are: (i) in common with weak
turbulent cascades, wave packets belonging to the inertial range are long
lived; (ii) however, components of the strain tensor are so large that, similar
to the situation in strong turbulence, perturbation theory is not applicable;
(iii) the breakdown of perturbation theory results from the divergence of
neighboring field lines due to wave packets whose perturbations in velocity and
magnetic fields are localized, but whose perturbations in displacement are not;
(iv) 3--wave interactions dominate individual collisions between wave packets,
but interactions of all orders make comparable contributions to the
intermediate turbulent energy cascade; (v) successive collisions are correlated
since wave packets are distorted as they follow diverging field lines; (vi) in
common with the weak MHD cascade, there is no parallel cascade of energy, and
the cascade to small perpendicular scales strengthens as it reaches higher wave
numbers; (vii) For an appropriate weak excitation, there is a natural
progression from a weak, through an intermediate, to a strong cascade.Comment: 25 pages, to appear in The Astrophysical Journa
On the Dynamical Stability of the Solar System
A long-term numerical integration of the classical Newtonian approximation to
the planetary orbital motions of the full Solar System (sun + 8 planets),
spanning 20 Gyr, was performed. The results showed no severe instability
arising over this time interval. Subsequently, utilizing a bifurcation method
described by Jacques Laskar, two numerical experiments were performed with the
goal of determining dynamically allowed evolutions for the Solar System in
which the planetary orbits become unstable. The experiments yielded one
evolution in which Mercury falls onto the Sun at ~1.261Gyr from now, and
another in which Mercury and Venus collide in ~862Myr. In the latter solution,
as a result of Mercury's unstable behavior, Mars was ejected from the Solar
System at ~822Myr. We have performed a number of numerical tests that confirm
these results, and indicate that they are not numerical artifacts. Using
synthetic secular perturbation theory, we find that Mercury is destabilized via
an entrance into a linear secular resonance with Jupiter in which their
corresponding eigenfrequencies experience extended periods of commensurability.
The effects of general relativity on the dynamical stability are discussed. An
application of the bifurcation method to the outer Solar System (Jupiter,
Saturn, Uranus, and Neptune) showed no sign of instability during the course of
24Gyr of integrations, in keeping with an expected Uranian dynamical lifetime
of 10^(18) years.Comment: 37 pages, 18 figures, accepted for publication in the Astrophysical
Journa
Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly progress report no. 11, Mar. 1966
Breadboard model development of integrated static inverte
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