The Voyager magnetometer boom

The Voyager spacecraft magnetometer experiment utilizes two sensors on a deployable boom. The boom is an Astromast. The implementation of the Astromast into the Voyager design is described along with the hardware used to hold, latch, and deploy the mast and the tests to demonstrate damping, deployment, and alignments. Several problems encountered are discussed and their solutions are given. Flight deployment and preliminary alignment results are presented. Finally, the design is evaluated in retrospect

Improved measurement of depth perception

Electromechanical system for Howard-Dolman device was developed. System is used for human depth perception measurements without tactual stimuli

Thermal conductance of and heat generation in tire-pavement interface and effect on aircraft braking

A finite-difference analysis was performed on temperature records obtained from a free rolling automotive tire and from pavement surface. A high thermal contact conductance between tire and asphalt was found on a statistical basis. Average slip due to squirming between tire and asphalt was about 1.5 mm. Consequent friction heat was estimated as 64 percent of total power absorbed by bias-ply, belted tire. Extrapolation of results to aircraft tire indicates potential braking improvement by even moderate increase of heat absorbing capacity of runway surface

AVIRIS scan drive design and performance

The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) images the ground with an instantaneous field of view (IFOV) of 1 mrad. The IFOV is scanned 30 deg from left to right to provide the cross-track dimension of the image, while the aircraft's motion provides the along-track dimension. The scanning frequency is 12 Hz, with a scan efficiency of 70 percent. The scan mirror has an effective diameter of 5.7 in, and its positional accuracy is a small fraction of a milliradian of the nominal position-time profile. Described are the design and performance of the scan drive mechanism. Tradeoffs among various approaches are discussed, and the reasons given for the selection of the cam drive

Noise predictions and economic effects of Boeing nacelle modifications

Noise level predictions and economics of Boeing nacelle modification

Analysis of Linsker's simulations of Hebbian rules

Linsker has reported the development of center-surround receptive fields and oriented receptive fields in simulations of a Hebb-type equation in a linear network. The dynamics of the learning rule are analyzed in terms of the eigenvectors of the covariance matrix of cell activities. Analytic and computational results for Linsker's covariance matrices, and some general theorems, lead to an explanation of the emergence of center-surround and certain oriented structures. We estimate criteria for the parameter regime in which center-surround structures emerge

Conditions driving chemical freeze-out

We propose the entropy density as the thermodynamic condition driving best the chemical freeze-out in heavy-ion collisions. Taking its value from lattice calculations at zero chemical potential, we find that it is excellent in reproducing the experimentally estimated freeze-out parameters. The two characteristic endpoints in the freeze-out diagram are reproduced as well.Comment: 8 pages, 5 eps figure

On critical pilot tasks

Critical pilot performance in decision making proces

Polarization switching and induced birefringence in InGaAsP multiple quantum wells at 1.5 mu m

We analyze the 1.5mum wavelength operation of a room temperature polarization switch based on electron spin dynamics in InGaAsP multiple quantum wells. An unexpected difference in response for left and right circularly polarized pump light in pump-probe measurements was discovered and determined to be caused by an excess carrier induced birefringence. Transient polarization rotation and ellipticity were measured as a function of time delay. (C) 2002 American Institute of Physics.</p