Einstein’s nearly 90-year-old General Theory of Relativity is getting one of its most rigorous tests high above the Earth. The Gravity Probe B (GP-B) has been in orbit since April 2004 conducting what could be a two-year test of the so-called “frame-dragging” effect—the “twisting” of the local space-time fabric. Critical to the tests: advances in design of gyroscopes.
The Probe has four gyros. The gyro rotors are made of fused quartz and ground to near-absolute sphericity. The near-perfection of the ping pong-size gyros is necessary because imperfection can distort their position: They will be pointing to a reference guide star. The frame dragging that distots the space-time fabric, theoretically would distort the gyroscopes too. But imperfections in the gyros themselves could also cause distortion, invalidating the experiment.
Engineers levitated the rotors with three saucer-shaped electrodes so they could suspend them in their cavity without disturbing the spin. To get and keep the rotors spinning, they directed a precise stream of helium gas at the rotors. And, they used superconductivity as the basis of a noninterfering pointer readout based on the superconducting quantum interference device (SQUID). It senses any angular shift in the rotor spin axis.
Though the GP-B has another 16 or so months to go, engineers have already achieved successes, including advanced gyro fabrication, near-perfect elimination of interfering magnetic fields, and telescope pointing and control.
New versions of BASF's Ecovio line are both compostable and designed for either injection molding or thermoforming. These combinations are becoming more common for the single-use bioplastics used in food service and food packaging applications, but are still not widely available.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This radio show will show what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.