Archive for the ‘materials’ category: Page 13

Jul 10, 2020

New technique turns junk into valuable graphene

Posted by in category: materials

Graphene is insanely useful, but very difficult to produce — until now.

Jul 8, 2020

Contest between superconductivity and insulating states in ‘magic angle’ graphene

Posted by in categories: materials, physics

If you stack two layers of graphene one on top of the other, and rotate them at an angle of 1.1º (no more and no less) from each other—the so-called ‘magic-angle,’ experiments have proven that the material can behave like an insulator, where no electrical current can flow, and at the same can also behave like a superconductor, where electrical currents can flow without resistance.

This major finding took place in 2018. Last year, in 2019, while ICFO researchers were improving the quality of the device used to replicate such breakthroughs, they stumbled upon something even bigger and totally unexpected. They were able to observe a zoo of previously unobserved superconducting and correlated states, in addition to an entirely new set of magnetic and topological states, opening a completely new realm of richer physics.

So far, there is no theory that has been able to explain superconductivity in magic angle graphene at the microscopic level. However, this finding has triggered many studies, which are trying to understand and unveil the physics behind all these phenomena that occur in this material. In particular, scientists drew analogies to unconventional high temperature superconductors—the cuprates, which hold the record highest superconducting temperatures, only 2 times lower than . Their microscopic mechanism of the superconducting phase is still not understood, 30 years after its discovery. However, similarly to magic angle twisted bi-layer graphene (MATBG), it is believed that an insulating phase is responsible for the superconducting phase in proximity to it. Understanding the relationship between the superconducting and insulating phases is at the center of researcher’s interest, and could lead to a big breakthrough in superconductivity research.

Jul 7, 2020

Shock-dissipating fractal cubes could forge high-tech armor

Posted by in categories: 3D printing, materials

Tiny, 3D printed cubes of plastic, with intricate fractal voids built into them, have proven to be effective at dissipating shockwaves, potentially leading to new types of lightweight armor and structural materials effective against explosions and impacts.

“The goal of the work is to manipulate the wave interactions resulting from a ,” said Dana Dattelbaum, a scientist at Los Alamos National Laboratory and lead author on a paper to appear in the journal AIP Advances. “The for how to do so have not been well defined, certainly less so compared to mechanical deformation of additively manufactured materials. We’re defining those principles, due to advanced, mesoscale manufacturing and design.”

Shockwave dispersing materials that take advantage of voids have been developed in the past, but they typically involved random distributions discovered through trial and error. Others have used layers to reverberate shock and release waves. Precisely controlling the location of holes in a material allows the researchers to design, model and test structures that perform as designed, in a reproducible way.

Jul 6, 2020

Napa-raised astronaut Kate Rubins prepares for return to International Space Station in October

Posted by in categories: biotech/medical, materials

Kate Rubins, the first Napa native to go to space, is entering the final three months of preparation for her return trip to the International Space Station where she served four years ago.

Starting Oct. 14 and continuing for about six months, her schedule will be replete with scientific work 250 miles above the Earth, dealing with materials ranging from supercold gases to stem cells. And unlike during her first stay in 2016, Rubins expects to get to work quickly, without the awkward introduction to moving about in microgravity.

“As a rookie you’re not so good at navigating and flying through the space station, so you tend to crawl hand over hand on the handrails,” the biochemist-turned-space traveler quipped during a NASA news conference last week in Houston, while recalling her original 115-day stint aboard the orbiting space platform.

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Jul 6, 2020

New insights into van der Waals materials found

Posted by in categories: materials, particle physics

Layered van der Waals materials are of high interest for electronic and photonic applications, according to researchers at Penn State and SLAC National Accelerator Laboratory, in California, who provide new insights into the interactions of layered materials with laser and electron beams.

Two-dimensional van der Waals materials are composed of strongly bonded layers of molecules with weak bonding between the layers.

The researchers used a combination of ultrafast pulses of laser light that excite the atoms in a material lattice of gallium telluride, followed by exposing the lattice to an ultrafast pulse of an . This shows the lattice vibrations in real time using and could lead to a better understanding of these materials.

Jul 3, 2020

The lightest electromagnetic shielding material in the world

Posted by in categories: chemistry, materials

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic components or the transmission of signals. High-frequency electromagnetic fields can only be shielded with conductive shells that are closed on all sides. Often thin metal sheets or metallized foils are used for this purpose. However, for many applications such a shield is too heavy or too poorly adaptable to the given geometry. The ideal solution would be a light, flexible and durable material with extremely high shielding effectiveness.

Aerogels against electromagnetic radiation

A breakthrough in this area has now been achieved by a research team led by Zhihui Zeng and Gustav Nyström. The researchers are using nanofibers of as the basis for an aerogel, which is a light, highly porous material. Cellulose fibers are obtained from wood and, due to their , enable a wide range of chemical modifications. They are therefore a highly popular research object. The crucial factor in the processing and modification of these cellulose nanofibres is to be able to produce certain microstructures in a defined way and to interpret the effects achieved. These relationships between structure and properties are the very field of research of Nyström’s team at Empa.

Jun 29, 2020

A snapshot shows off super-material only two atoms thick

Posted by in categories: materials, particle physics

High-powered microscope allows scientists to visualize an exotic structure called a superlattice.

Jun 28, 2020

Newborn Pluto Was Hot and Had Subsurface Ocean: Study

Posted by in categories: materials, space

Pluto is thought to possess a subsurface ocean beneath its thick ice shell. It has generally been assumed that the dwarf planet formed out of cold material and then later developed its ocean due to warming from radioactive decay. By combining numerical simulations with geological observations by NASA’s New Horizons mission, a team of researchers from the University of California Santa Cruz and the Southwest Research Institute demonstrated that Pluto was instead relatively hot when it formed, with an early subsurface ocean.

Jun 24, 2020

You Can “Feel“ Your GPS Directions With This Exoskin

Posted by in category: materials

Click on photo to start video.

This shape-shifting material is blowing our minds.

Jun 22, 2020

“Intelligent Concrete” Heals Itself – Enabling Highways and Bridges to Prevent Their Own Damage

Posted by in categories: materials, transportation

‘Intelligent concrete’ could cut down on road repairs and traffic.

Roads always seem to need repairs. Luna Lu is giving concrete the ability to “talk” and even heal itself.

Her lab at Purdue University is developing technology that would allow concrete-paved bridges and highways to reveal more accurately when they need repairs and to come equipped with materials that respond to potential damage.

Continue reading “‘Intelligent Concrete’ Heals Itself – Enabling Highways and Bridges to Prevent Their Own Damage” »

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