If you think Superman is fast, talk to Marcus Knudsun. His "Z accelerator" uses a magnetic field to hurl tiny plates at speeds up to 20 km/sec. At 20 times faster than a bullet fired from a rifle, the tiny plates are fast enough to leave most superheroes in the dust and also help aerospace and telecommunications engineers simulate how space debris affects the metal skin of orbiting satellites and space observatories. Knudson is a physicist at Sandia National Labs who is researching how materials react to pressure and temperature. "The impact velocities of space debris can be quite high, on the order of 20 km/sec," says Knudson. Beyond 20 km/sec, the temperature of the aluminum plates reaches 2,500K and the plates melt. The propulsion technique that Knudson uses works by applying the Z accelerators at 20 million amps to produce an evolving magnetic field that expands in approximately 200 nsec, ultimately reaching several million atmospheres of pressure. The resulting expansion of the magnetic field propels the small plates, just as a surfboarder who catches a wave is propelled through space. "The amount of mass that is launched to high velocity is limited to a pellet weighing a couple hundred milligrams," Knudson says. "The technology will allow testing of debris shields, something that would be of interest to NASA and the communications industry," he explains. The technique is said to be the fastest, cheapest, and easiest way to determine how materials react to high pressures and temperature. For more information, contact Knudson at (505) 845-7796 or firstname.lastname@example.org.
Two different shape-shifting polymers have been announced from two different universities: Wyss Institute at Harvard University and Zhejiang University in eastern China. Both of them change their shapes when immersed in water, and the one from Wyss Institute was made with 3D-printing techniques.
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