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Archive for the ‘materials’ category: Page 224

Sep 9, 2019

Hard as a diamond? Scientists predict new forms of superhard carbon

Posted by in categories: materials, particle physics

Superhard materials can slice, drill and polish other objects. They also hold potential for creating scratch-resistant coatings that could help keep expensive equipment safe from damage.

Now, science is opening the door to the development of new materials with these seductive qualities.

Researchers have used computational techniques to identify 43 previously unknown forms of that are thought to be stable and superhard—including several predicted to be slightly harder than or nearly as hard as diamonds. Each new carbon variety consists of carbon atoms arranged in a distinct pattern in a .

Sep 9, 2019

Crucial New Aspect of Charge Density Modulations in High Temperature Superconductors Uncovered

Posted by in category: materials

Researchers from Chalmers University of Technology and Politecnico di Milano have identified a crucial new aspect of charge density modulations in cuprate high critical temperature superconductors. They have identified a new electron wave which could help reveal some of the mysteries about superconducting materials. The findings are published in the journal Science.

High critical temperature superconductors have a variable charge density, meaning that their electrical charge is unevenly distributed. This partly results from what are known as ‘charge density waves’, which were discovered a few years ago. But these have only been observed to exist sporadically, under certain conditions. Therefore, they were not believed to be a contributing factor to the materials’ superconducting properties.

What the researchers have now discovered, however, is an additional aspect to the variable charge density, which they term “charge density fluctuations”. These have been identified as an additional charge modulation, collective and with a shorter correlation length. They are very pervasive, meaning that compared to the conventional charge density waves, they are present at a much greater range of temperatures, up to room temperature and beyond, and at different levels of oxygen doping.

Sep 6, 2019

Measuring changes in magnetic order to find ways to transcend conventional electronics

Posted by in categories: futurism, materials

Researchers around the world are constantly looking for ways to enhance or transcend the capabilities of electronic devices, which seem to be reaching their theoretical limits. Undoubtedly, one of the most important advantages of electronic technology is its speed, which, albeit high, can still be surpassed by orders of magnitude through other approaches that are not yet commercially available.

A possible way of surpassing traditional electronics is through the use of (AFM) materials. The electrons of AFM materials spontaneously align themselves in such a way that the overall magnetization of the material is practically zero. In fact, the order of an AFM material can be quantified in what is known as the ‘order parameter.’ Recent studies have even shown that the AFM order parameter can be ‘switched’ (that is, changed from one known value to another, really fast) using light or , which means that AFM materials could become the building blocks of future electronic devices.

However, the dynamics of the order-switching process are not understood because it is very difficult to measure the changes in the AFM order parameter in real time with high resolution. Current approaches rely on measuring only certain phenomena during AFM order switching and trying to obtain the full picture from there, which has proven to be unreliable for understanding other more intricate phenomena in detail. Therefore, a research team lead by Prof. Takuya Satoh from Tokyo Tech and researchers from ETH Zurich, developed a method for thoroughly measuring the changes in the AFM order of an YMnO3 crystal induced through optical excitation (that is, using a laser).

Aug 30, 2019

A predicted superconductor might work at a record-breaking 200° Celsius

Posted by in category: materials

Y. Sun et al. Route to a superconducting phase above room temperature in electron-doped hydride compounds under high pressure. Physical Review Letters. Vol. 123, August 30, 2019. doi:10.1103/PhysRevLett.123.097001.

Aug 29, 2019

Scientists discover photovoltaic nanotubes

Posted by in categories: materials, nanotechnology

An international team of researchers led by the University of Tokyo has discovered a new material which, when rolled into a nanotube, generates an electric current if exposed to light. If magnified and scaled up, say the scientists, the technology could be used in future high-efficiency solar devices.

Aug 29, 2019

SpaceX’s first Super Heavy hardware is already being built at Florida Starship campus

Posted by in categories: materials, space travel

Based on some basic analysis of recent photos of SpaceX’s East Coast Starship facility, situated in Cocoa, Florida, SpaceX has almost certainly begun fabricating and staging hardware that will eventually become part of the company’s first Super Heavy booster prototype.

This is by no means surprising but it does confirm the reasonable assumption that SpaceX is already working hard to ensure that the first Super Heavy booster(s) can be assembled as quickly as possible. Additionally, SpaceX appears to have started clearing brush in the process of preparing to transport the Florida orbital Starship prototype (“Mk2”) to SpaceX’s Pad 39A launch facilities, dozens of miles away.

The aforementioned “basic analysis” is more or less comprised of looking for and counting the massive steel rings that SpaceX has decided to build its Starships (and Super Heavy boosters) out of. By all appearances, SpaceX is doing nearly everything short of milling and preparing the raw materials (steel) internally. In Florida and Texas, giant rolls of stainless steel are delivered to the worksite by semi-truck, where SpaceX technicians prepare the rolls for sectioning (likely with a plasma torch or laser) and any necessary machining.

Aug 29, 2019

Water harvester wrings drinking water out of dry desert air

Posted by in categories: materials, sustainability

As vital as clean water is for human life, unfortunately it’s not always easy for people to get enough. Adding insult to injury, the stuff is basically always floating around us in the air, unreachable. Now, researchers from the University of California Berkeley have developed a device that can wring drinkable amounts of water out of even the driest air.

The team says this new water harvester can produce more than 1.3 L (5.4 US cups) of water per day per kilogram (2.2 lb) of a particular water-absorbing material. This can be done even at less than 40 percent relative humidity. That’s not a whole lot of water, but it is more than enough to keep a person alive, if a situation was that dire.

The harvester was put to the test over three days in the Mojave Desert. During that time, the device produced 0.7 L (3 cups) of water per kg of material, and even on the driest day the harvester managed to wring 200 ml (6 oz) of water out of air that had an extremely low relative humidity of just seven percent.

Aug 27, 2019

These Researchers Want to Run a Cable From the Earth to the Moon

Posted by in categories: materials, space travel

It would be much easier to escape Earth’s gravity if you could skip the energy-intensive rockets.

That’s the idea behind the Spaceline, a newly-proposed type of space elevator that would link the Earth and the Moon in a bid drastically cut the cost of space travel.

Described in research published to the preprint server ArXiv by researchers at Columbia University and Cambridge University, the Spaceline would be tethered to the surface of the Moon and dangle down into geostationary orbit around the Earth like a plumb bob, waiting for astronauts to latch on and ride into the cosmos. The proof-of-concept paper found that the Spaceline could be constructed out of materials that exist today, raising the possibility of easier space travel and perhaps even orbital settlements.

Aug 27, 2019

Adding Graphene to Fabrics Turns It Into a Perfect Force Field Against Mosquitoes

Posted by in categories: biotech/medical, materials

Saying goodbye to the warm summer months is a little easier when it also means the war against mosquito bites is coming to an end. They’re not just an itchy annoyance, however, mosquitoes can spread dangerous diseases and viruses, but researchers at Brown University might have come up with the perfect mosquito forcefield: garments lined with graphene.

Aug 26, 2019

Disappearing act: Device vanishes on command after military missions

Posted by in categories: materials, military

https://youtube.com/watch?v=A7QXerW77I4

A polymer that self-destructs? While once a fictional idea, new polymers now exist that are rugged enough to ferry packages or sensors into hostile territory and vaporize immediately upon a military mission’s completion. The material has been made into a rigid-winged glider and a nylon-like parachute fabric for airborne delivery across distances of a hundred miles or more. It could also be used someday in building materials or environmental sensors.

The researchers will present their results today at the American Chemical Society (ACS) Fall 2019 National Meeting & Exposition.

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