Mechanization of and experience with a triplex fly-by-wire backup control system

A redundant three axis analog control system was designed and developed to back up a digital fly by wire control system for an F-8C airplane. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum displacement (force) side stick. The operational reliability of the F-8 digital fly by wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed

Mechanization of and experience with a triplex fly-by-wire backup control system

A redundant three-axis analog control system was designed and developed to back up a digital fly-by-wire control system for an F-8C airplane. Forty-two flights, involving 58 hours of flight time, were flown by six pilots. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum-displacement (force) side stick. The operational reliability of the F-8 digital fly-by-wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed

Initial Results from a Stacked Ring Apparatus for Simulation of a Soil Profile

A stack of 48 rings, lined with a latex membrane, is used to confine a column of soil 12 inches high by 12 inches in diameter (300 mm x 300 mm). Both dry and saturated columns of fine sand are shaken at their base, at a centrifugal acceleration of 35.5 g. Measurements of the settlement of the surface, horizontal displacement and pore pressures show that the columns of soil are behaving essentially (although not exactly) as one-dimensional shear beams

Eleonora V. Eckert

Tributes to Eleonora V. Ecker

Structure and Stability of Si(114)-(2x1)

We describe a recently discovered stable planar surface of silicon, Si(114). This high-index surface, oriented 19.5 degrees away from (001) toward (111), undergoes a 2x1 reconstruction. We propose a complete model for the reconstructed surface based on scanning tunneling microscopy images and first-principles total-energy calculations. The structure and stability of Si(114)-(2x1) arises from a balance between surface dangling bond reduction and surface stress relief, and provides a key to understanding the morphology of a family of surfaces oriented between (001) and (114).Comment: REVTeX, 4 pages + 3 figures. A preprint with high-resolution figures is available at http://cst-www.nrl.navy.mil/papers/si114.ps . To be published in Phys. Rev. Let

First principles theory of inelastic currents in a scanning tunneling microscope

A first principles theory of inelastic tunneling between a model probe tip and an atom adsorbed on a surface is presented, extending the elastic tunneling theory of Tersoff and Hamann. The inelastic current is proportional to the change in the local density of states at the center of the tip due to the addition of the adsorbate. We use the theory to investigate the vibrational heating of an adsorbate below an STM tip. We calculate the desorption rate of H from Si(100)-H(2$\times$1) as function of the sample bias and tunnel current, and find excellent agreement with recent experimental data.Comment: 5 pages, RevTeX, epsf file

Versatile single-molecule multi-color excitation and detection fluorescence setup for studying biomolecular dynamics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98644/1/RevSciInstrum_82_113702.pd

Static charged perfect fluid spheres in general relativity

Interior perfect fluid solutions for the Reissner-Nordstrom metric are studied on the basis of a new classification scheme. General formulas are found in many cases. Explicit new global solutions are given as illustrations. Known solutions are briefly reviewed.Comment: 23 pages, Revtex (galley), journal version, to appear in Phys.Rev.

Plasma-binding globulins and acute stress response

Within studies of acute stress physiology an increase in glucocorticoid secretion is thought to be the primary mediator of tissue response to stress. Corticosteroid-binding globulin may regulate tissue availability of steroids, but has not been considered a dynamic component of the acute stress response. Here, we examined CBG level over the common 60-minute time frame in an acute capture and handling protocol to investigate whether CBG capacity is dynamic or static over short stressors. Using a comparative approach, we measured CBG response to capture and handling stress in nine species of birds, representing five orders and nine families. CBG capacity significantly declined within 30-60 minutes of capture in five of the nine species examined. This decline may serve to significantly increase the level of corticosterone reaching tissues during acute stress. © Georg Thieme Verlag KG Stuttgart

Plasma-binding globulins and acute stress response

Within studies of acute stress physiology an increase in glucocorticoid secretion is thought to be the primary mediator of tissue response to stress. Corticosteroid-binding globulin may regulate tissue availability of steroids, but has not been considered a dynamic component of the acute stress response. Here, we examined CBG level over the common 60-minute time frame in an acute capture and handling protocol to investigate whether CBG capacity is dynamic or static over short stressors. Using a comparative approach, we measured CBG response to capture and handling stress in nine species of birds, representing five orders and nine families. CBG capacity significantly declined within 30-60 minutes of capture in five of the nine species examined. This decline may serve to significantly increase the level of corticosterone reaching tissues during acute stress. © Georg Thieme Verlag KG Stuttgart