Category: materials – Page 151
Hart outlines the differences between contemporary analytic styles of theistic thought and classical theism.
For those interested, I invite you to join the “Fans of David Bentley Hart” Facebook group, where you can post/discuss DBH material. Feel free to join here: https://www.facebook.com/groups/552331154934653/
All About Diamonds & Graphene
Posted in materials
The ability to turn superconductivity off and on with a literal flip of a switch in so-called “magic-angle twisted graphene” has allowed engineers at Caltech to observe an unusual phenomenon that may shed new light on superconductivity in general.
The research, led by Stevan Nadj-Perge, assistant professor of applied physics and materials science, was published in the journal Nature on June 15.
Magic-angle twisted graphene, first discovered in 2018, is made from two or three sheets of graphene (a form of carbon consisting of a single layer of atoms in a honeycomb-like lattice pattern) layered atop one another, with each sheet twisted at precisely 1.05 degrees in relation to the one below it. The resulting bilayer or trilayer has unusual electronic properties: for example, it can be made into an insulator or a superconductor depending on how many electrons are added.
Martin ChartrandListen to the sound, more like a musket than a 3D printed plastic gun.
Second video shows the attempted assassination of former Japanese Prime Minister Shinzo Abe
NOTE: Video not graphic, but viewer discretion is advised pic.twitter.com/BZNGHP78ds
— BNO News (@BNONews) July 8, 2022
When it comes to graphene, it appears that superconductivity runs in the family.
Graphene is a single-atom-thin material that can be exfoliated from the same graphite that is found in pencil lead. The ultrathin material is made entirely from carbon atoms that are arranged in a simple hexagonal pattern, similar to that of chicken wire. Since its isolation in 2004, graphene has been found to embody numerous remarkable properties in its single-layer form.
In 2018, MIT researchers found that if two graphene layers are stacked at a very specific “magic” angle, the twisted bilayer structure could exhibit robust superconductivity, a widely sought material state in which an electrical current can flow through with zero energy loss. Recently, the same group found a similar superconductive state exists in twisted trilayer graphene—a structure made from three graphene layers stacked at a precise, new magic angle.
Mars has had its first CT scan, thanks to analyses of seismic waves picked up by NASA’s InSight lander. Diagnosis: The Red Planet’s core is at least partially liquid, as some previous studies had suggested, and is somewhat larger than expected.
InSight reached Mars in late 2018 and soon afterward detected the first known marsquake (SN: 11/26/18; SN: 4/23/19). Since then, the lander’s instruments have picked up more than a thousand temblors, most of them minor rumbles. Many of those quakes originated at a seismically active region more than 1,000 kilometers away from the lander. A small fraction of the quakes had magnitudes ranging from 3.0 to 4.0, and the resulting vibrations have enabled scientists to probe Mars and reveal new clues about its inner structure.
Simon Stähler, a seismologist at ETH Zurich, and colleagues analyzed seismic waves from 11 marsquakes, looking for two types of waves: pressure and shear. Unlike pressure waves, shear waves can’t pass through a liquid, and they move more slowly, traveling side to side through solid materials, rather than in a push-and-pull motion in the same direction a wave is traveling like pressure waves do.
Osaka University researchers discovered that worms may be coated with hydrogel sheaths that contain useful cargo such as anti-cancer medications
James Bond’s famed quartermaster Q provided the secret agent with an unlimited supply of equipment and gadgets to aid him on his missions. Now, scientists from Japan have shown that they are equally adept in providing microscopic worms with a surprising variety of useful and protective components.
Researchers from Osaka University have discovered that microscopic, free-living worms known as nematodes may be coated with hydrogel-based “sheaths” that can be further customized to transport functional cargo.
Physicists have discovered that certain magnetic material freezes when the temperature rises to a certain point. We’ve typically only seen this behavior when we cool down magnetic materials, not when we heat them up. As such, it has left physicists scratching their heads and baffled by the development.
Physicists Alexander Khajetoorians of Radboud University in the Netherlands says that the freezing of the magnetic materials is the opposite of what we normally see. The result is “counterintuitive, like water that becomes an ice cube when it’s heated up,” according to Khajetoorians.
Normally, ferromagnetic materials like iron feature aligned spins. This means that the magnetic spins of the atoms are all spinning in the same direction. Essentially, the south and north magnetic poles are all aligned in the same direction. Some alloys made of both iron and copper, though, feature randomized spins. Physicists refer to this state as spin glass.
Though they are discrete particles, water molecules flow collectively as liquids, producing streams, waves, whirlpools, and other classic fluid phenomena.
Not so with electricity. While an electric current is also a construct of distinct particles—in this case, electrons —the particles are so small that any collective behavior among them is drowned out by larger influences as electrons pass through ordinary metals. But, in certain materials and under specific conditions, such effects fade away, and electrons can directly influence each other. In these instances, electrons can flow collectively like a fluid.
Now, physicists at MIT and the Weizmann Institute of Science have observed electrons flowing in vortices, or whirlpools—a hallmark of fluid flow that theorists predicted electrons should exhibit, but that has never been seen until now.