https://wyss.harvard.edu/soft-exosui...ning-the-load/
(CAMBRIDGE, Massachusetts) — Last year, Harvard’s soft exosuit team provided first proof-of-concept results showing that its wearable robot could lower energy expenditure in healthy people walking with a load on their back. Made of functional textiles, cable-based actuation and a biologically-inspired control system, the exosuit targets specific leg joints – instead of the full leg – and delivers assistance that is synchronized with the wearer’s walking mechanics in individuals ranging from people that carry heavy loads to people that are disabled by stroke or other health complications.
The team is led by Conor Walsh, a Wyss Institute Core Faculty member, John L. Loeb Associate Professor of Engineering and Applied Sciences at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Founder of the Harvard Biodesign Lab.
To follow up on the Planet 9 story. Some scientists now think it could be a Rogue World.
http://www.space.com/35277-planet-ni...exoplanet.html
https://phys.org/news/2017-01-metall...y-reality.html
Nearly a century after it was theorized, Harvard scientists have succeeded in creating the rarest - and potentially one of the most valuable - materials on the planet.
Read more at: https://phys.org/news/2017-01-metall...ality.html#jCp
The material - atomic metallic hydrogen - was created by Thomas D. Cabot Professor of the Natural Sciences Isaac Silvera and post-doctoral fellow Ranga Dias. In addition to helping scientists answer fundamental questions about the nature of matter, the material is theorized to have a wide range of applications, including as a room-temperature superconductor. The creation of the rare material is described in a January 26 paper published in Science.
"This is the holy grail of high-pressure physics," Silvera said. "It's the first-ever sample of metallic hydrogen on Earth, so when you're looking at it, you're looking at something that's never existed before."
To create it, Silvera and Dias squeezed a tiny hydrogen sample at 495 gigapascal, or more than 71.7 million pounds-per-square inch - greater than the pressure at the center of the Earth. At those extreme pressures, Silvera explained, solid molecular hydrogen -which consists of molecules on the lattice sites of the solid - breaks down, and the tightly bound molecules dissociate to transforms into atomic hydrogen, which is a metal.
This will be interesting.
Though it has the potential to transform life on Earth, metallic hydrogen could also play a key role in helping humans explore the far reaches of space, as the most powerful rocket propellant yet discovered.
"It takes a tremendous amount of energy to make metallic hydrogen," Silvera explained. "And if you convert it back to molecular hydrogen, all that energy is released, so it would make it the most powerful rocket propellant known to man, and could revolutionize rocketry."
So, I read about this, and it sounds cool, but makes me realize that I don't know what metal is.
I mean, "metallic hydrogen" - so it's solid at room temperature? But it's 100% hydrogen atoms? So...is it the arrangement of the atoms in the molecule? What is the molecular structure?
I guess metallic hydrogen is a distinct phase? Not solid, liquid, gas, or plasma? This is beyond my understanding of atomic physics.
Disclaimer: Not a condensed matter guy.
Metallic hydrogen is solid atomic hydrogen that conducts electricity (this is the metal bit). There are no molecular bonds. It's a bunch of protons shoved together under so much pressure that they lose the ability to hold their electrons in stable orbits.
Metallic just means a set of properties that it exhibits. Think alkaline, inert, etc. Solid/liquid/gas/etc doesn't matter, but properties do.
So...does it stop being metallic once you remove it from the ultra high pressure environment?
Get one of our actual scientists to confirm, but iirc a lot of the properties of an element are due to electron orbits. So if the pressure is forcing the electrons out of the atom structure, then it would retain the metallic properties even after being removed from the pressure.
From what i understood reading about it, thats what they are hoping doesn't happen they want it to keep its metallic properties once the pressure is removed. Think diamonds, just carbon thats been placed under huge pressure but it keeps its composition/stucture once that pressure is released, thats what they want to happen with this.
I should note i'm in no way a qualified scientist so could probably be totally off on all of that.
This would be super cool if it ends up being true, but others at Harvard think this might be a case of misidentification. Looking forward to some replication/verification.
Can't we make real diamonds now with a process like this or do we already or is it just pointless.
from what i understand of metals, its basically the electrons are no longer localized. aka it's not two atoms sharing electrons anymore, but a bunch of molocules with electrons flowing between all of them... sorta like the molecular bonds grew so big they up and merged together into one big megabond that encompasses the whole shebang. since they're no longer held into local orbits between two molocules (well, maybe orbit isn't the right word, as electrons don't do something so tidy as an ellipse) the electrons can flow freely between the lump of metal, giving rise to the metallic property of high electrical conductivity (read: electrons can flow fairly easily through the metal)
granted my memory is rather rusty on this and im too lazy to wiki it. id imagine that delocalization of electrons also gives rise to metals low specific heat capacities, and allow them to be ductile and malleable (aka can be pulled into wires and pounded into shapes instead of cracking along weaker links and bonds from impurities in a substance)
diamonds are actually not metals, but crystals. they still have bonds shared between two atoms instead of electron delocalization. crystals have a repeating pattern to them... in diamonds case hexagons linked together with bonds(with some pentagons). diamonds are so strong because fuck yeah hexagons. and because carbon is awesome like that.
metals, by contrast, do NOT have a repeating pattern... theyre basically a soup of atoms held together with delocalized atoms swarming all over the place.
this is different from plain old non crystalline substances, which are still atoms bound together with atomic bonds shared between two atoms, but without a regular repeating pattern.
As awesome as all this sounds, I've seen a lot of pushback from other "experts" that believe it's bullshit. Here's to hoping it's true!
We do. Something like 97% of industrial-application diamonds are synthetic.
But are they pretty
Industrial use diamonds? lol no
Gemstones in general are not pretty until they're cut to refract light, which industrial use diamond is not.
Industrial use, no. But there are companies that make jewelry-quality diamonds. They're indistinguishable from natural diamonds without expensive, specialized equipment; and cost about 30% less.