BgLUG Bergamo: Brindisi di Natale al FabLab Bergamo 🎅
Segnalato dal calendario eventi di Linux Italia e pubblicato sulla comunità Lemmy @GNU/Linux Italia
Sabato 20 dicembre di pomeriggio faremo un brindisi di natale.
Germanium Semiconductor Made Superconductor by Gallium Doping
Over on ScienceDaily we learn that an international team of scientists have turned a common semiconductor germanium into a superconductor.
Researchers have been able to make the semiconductor germanium superconductive for the first time by incorporating gallium into its crystal lattice through the process of molecular-beam epitaxy (MBE). MBE is the same process which is used in the manufacture of semiconductor devices such as diodes and MOSFETs and it involves carefully growing crystal lattice in layers atop a substrate.
When the germanium is doped with gallium the crystalline structure, though weakened, is preserved. This allows for the structure to become superconducting when its temperature is reduced to 3.5 Kelvin.
It is of course wonderful that our material science capabilities continue to advance, but the breakthrough we’re really looking forward to is room-temperature superconductors, and we’re not there yet. If you’re interested in progress in superconductors you might like to read about Floquet Majorana Fermions which we covered earlier this year.
Underwater Jetpack is Almost Practical
The jet pack is one of those pre-war sci-fi dreams that the cold light of rational consideration reveals to be a terrible idea. Who wants to cook their legs with hot exhaust while careening out of control? Nobody. Yet it’s such an iconic idea, we can’t get away from it. What if there was a better environment, one where your jetpack dreams could come true? [CPSdrone] has found one: the world’s oceans, and have taken that revelation to build the world’s fastest underwater jetpack.
Underwater? Yeah, water drag is worse than air drag. But there are two big advantages: one, humans are fairly buoyant, so you don’t need fight gravity with rocket thrust, and two, the high density of water makes small, electric props a reasonable proposition. The electric ducted fans on this “jetpack” each produce about 110 pounds of thrust, or just over 490 N. The first advantage is helped further by the buoyancy provided by the air-filled “hull” of the jetpack. That’s necessary because while the motors might be rated for submersion, but the rest of the electronics aren’t.
Alas, wearing the device on the back is considerably less hydrodynamic than hanging on behind in the standard ‘water scooter’ configuration. While they’re able to go faster than a swimming human, the ESCs weren’t able to handle the motors full power so we can’t tell you if this device would allow [CPSdrone] to outrun a shark with those 220 lbf on tap, which was the design goal. Apparently they’re working on it.
From the testing done on-screen, it’s safe to say that they’d at least need to hang on behind to get their desired speed goals, and abandon their jet pack dreams just as we landlubbers were forced to do long ago. Well, some of us, anyway.
youtube.com/embed/RjUV6Y-baDY?…