High voltage solid-state relay

Hybrid microelectronics relay has characteristics significantly superior to conventional solid state relays. Relay provides 2500 Vdc input to output isolation and operates from high threshold logic signal to switch load of 400 Vdc at 2 mA. Technology should be of interest to manufacturers of discrete components

A Ka-band (32 GHz) beacon link experiment (KABLE) with Mars Observer

A proposal for a Ka-Band (32 GHz) Link Experiment (KABLE) with the Mars Observer mission was submitted to NASA. The experiment will rely on the fourth harmonic of the spacecraft X-band transmitter to generate a 33.6 GHz signal. The experiment will rely also on the Deep Space Network (DSN) receiving station equipped to simultaneously receive X- and Ka-band signals. The experiment will accurately measure the spacecraft-to-Earth telecommunication link performance at Ka-band and X-band (8.4 GHz)

Second Epoch Global VLBI Observations of Compact Radio Sources in the M82 Starburst Galaxy

We have presented the results of a second epoch of global Very Long Baseline Interferometry observations, taken on 23 February 2001 at a wavelength of 18 cm, of the central kiloparsec of the nearby starburst galaxy Messier 82. These observations were aimed at studying the structural and flux evolution of some of the compact radio sources in the central region that have been identified as supernova remnants. The objects 41.95+575 and 43.31+592 have been studied, expansion velocities of 2500 +/- 1200 km/s and 7350 +/- 2100 km/s respectively have been derived. Flux densities of 31.1 +/- 0.3 mJy and 17.4 +/- 0.3 mJy have been measured for the two objects. These results are consistent with measurements and predictions from previous epochs.Comment: 5 pages, 3 figures. To be published on the accompanying CD of the Proceedings of IAU Colloquium 192: Supernova

Rubidium spacecraft atomic timing system Final report

Rubidium 87 atomic time and frequency reference system for manned space fligh

Determinants of Fatigue in the Biceps Brachii During Blood Flow Restriction Training

poster abstractTraining loads of 60% - 80% of maximum are traditionally recommended for increasing muscular strength. Lifting lighter loads (~20% of 1RM) with concomitant blood flow restriction (BFR) can also increase muscle strength. It is unknown if adaptation with BFR is limited to the muscle or also due to changes in the nervous system. We examined changes in the output of the motor cortex and the muscle with stimulation, when subjects perform 1.) Training with light loads, 2.) Training with light loads with BFR, and 3.) Training with moderate loads. 5 subjects completed three training sessions with the elbow flexor muscles. Maximal strength was measured before and after each training session. Voluntary activation was tested with cortical stimulation (TMS) and with electrical stimulation of the biceps during additional MVCs. Subjects trained with a block of 4 isometric contractions at 20% MVC (120s, 60s, 60s, 60s durations) or at 60% MVC (40s, 20s, 20s, 20s durations). Fatigue (% decrease in MVC after training) was similar between 20% with BFR and 60% conditions (18.6% and 16%) and less in the 20% without BFR condition (9.7%). Cortical voluntary activation decreased similarly between the 20% BFR and 60% conditions (-3.6% and -3.3%) and showed less change with 20% without BFR (-1.8%). Alternatively, with electrical stimulation of the muscle, both 20% training conditions showed a decline in voluntary activation (-3.1% and -5.15), while voluntary activation increased by 8% after the 60% condition. Similar levels of fatigue occur at different contraction intensities when BFR is applied during the lighter contraction. Both 20% with BFR and 60% loading causes deficits in cortical activation, though the limiting factor in the 20% BFR condition is a decrease in activation of the muscle directly, while in the 60% contraction it is due to an inability to drive the motorneuron pool sufficiently