Lyapunov Instability for a hard-disk fluid in equilibrium and nonequilibrium thermostated by deterministic scattering

We compute the full Lyapunov spectra for a hard-disk fluid under temperature gradient and shear. The system is thermalized by deterministic and time-reversible scattering at the boundary. This thermostating mechanism allows for energy fluctuations around a mean value which is reflected by only two vanishing Lyapunov exponents in equilibrium and nonequilibrium. The Lyapunov exponents are calculated with a recently developed formalism for systems with elastic hard collisions. In a nonequilibrium steady state the average phase space volume is contracted onto a fractal attractor leading to a negative sum of Lyapunov exponents. Since the system is driven inhomogeneously we do not expect the conjugate pairing rule to hold which is confirmed numerically.Comment: 13 pages (revtex) with 8 figures (encapsulated postscript

Rotating raster generator

A rotating raster generator is provided which enables display of a television raster at any arbitrary roll angle. The generator includes four integrator circuits each of which receives a first voltage input corresponding to the sine or cosine of the desired roll angle and a second input comprising conventional horizontal or vertical sync pulses. The integrator circuits each comprise an operational amplifier and a capacitor connected for producing a ramp output having a rate of change proportional to the roll angle input, an electronic switch responsive to the sync input for resetting the integrator, and a summer that adds the ramp output of the integrator to the roll angle input so as to provide a zero-centered deflection control voltage

X-ray measurements of stresses and defects in EFG and large grained polycrystalline silicon ribbons

The Bond method was employed to measure the lattice parameter in an area of 0.4 mm in diameter of EFG Si-ribbons to an accuracy of + or - 0.00008 A. A Bond goniometer was built which included a goniostat with a special specimen holder to mount ribbons 1 m in length and 75 mm in width which could be rotated about two orthogonal axes, and a Leitz microscope for precision alignment of a particular area into the center of the goniostat and the small primary X-ray beam. The (321) planes were found to be parallel to the surface of the ribbons with an angular spread of about 15 deg. The poles of the (111) planes clustered about an angle of 25 deg away from the surface normal, again with a spread of 10 deg. The lattice parameter of a small piece of ribbon material was found to be a sub o = 5.43075 A. A maximum stress of 115 MPa was observed in a fractured ribbon which corresponded to the fracture stress of single crystals of Si

Secondary cadmium-air batteries

Sponge cadmium electrodes for secondary cadmium-air batterie

Effect of resonance-oblateness coupling on a satellite orbit

Second order effects of the coupling between geopotential resonance and oblateness on a satellite orbit are calculated. Results show that: (1) these effects arise from the interaction of resonance with the secular changes of the orbit's node, perigee, and mean anomaly; (2) they have the same period and phase as first order resonance perturbations; and (3) their amplitudes are proportional to the square of the period and dominate the first order effects as the orbit becomes commensurate. A striking example of this coupling is seen in the 18 day resonance variation of the node of the orbit of the first earth resources technology satellite. Analysis of this one arc second (31m) variation yielded a strong 14th order constraint to the geopotential for odd degree terms. This constraint is poorly predicted by current models

The restricted problem of three bodies /3/ Final report

Variations of limiting asymptotic orbits with mass ratio for restricted three body proble

Secondary iron-air batteries

Self discharge, capacity maintenance, oxidation, and water loss problems in secondary iron-air batterie

The geopotential at synchronous-orbit altitudes

The earth's gravity potential at synchronous orbit satellite altitudes is studied by analyzing the small effects of the resonant harmonic of gravity in tracking data from eight satellites during 21 distinct drift-free arcs. Results show: (1) absolute accuracy of second degree resonant geopotential coefficients better than three percent and coefficients through fourth degree better than 15 percent; (2) positions of equilibrium points for geostationary satellites better than 1/2 degree; and (3) accuracy in predicting orbits for 24-hour satellites better than 1 degree for periods greater than 2 years

The drift of an inclined-orbit 24-hour satellite in an earth gravity field through fourth order

Drift of inclined-orbit 24-hour satellite in earth gravity field through fourth orde