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Archive for the ‘materials’ category: Page 229

May 28, 2019

What’s the Magic Behind Graphene’s ‘Magic’ Angle?

Posted by in category: materials

A new theoretical model may help explain the shocking onset of superconductivity in stacked, twisted carbon sheets.

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May 28, 2019

Civilization: Institutions, Knowledge and the Future — Samo Burja

Posted by in categories: futurism, materials

Our civilization is made up of countless individuals and pieces of material technology, which come together to form institutions and interdependent systems of logistics, development and production. These institutions and systems then store the knowledge required for their own renewal and growth.

We pin the hopes of our common human project on this renewal and growth of the whole civilization. Whether this project is going well is a challenging but vital question to answer.

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May 27, 2019

Researchers develop wood that can cool a home

Posted by in categories: habitats, materials

Wood has a series of tiny structures inside that are used to carry water and nutrients to all parts of a living tree. Scientists have now figured out how to harness those same small structures to keep a home cool. Researchers at the University of Maryland and the University of Colorado Boulder say that the material could save 20% in AC bills.

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May 27, 2019

New superconductivity record edges closer to room temperature

Posted by in category: materials

No matter how good a material is at conducting electricity, there’s usually some resistance – unless you use superconductive materials. Since they can conduct electricity with absolutely no loss, they could be revolutionary if not for one little problem: they only work if kept extremely cold. But now researchers at Max Planck have reported a new record high temperature for superconductivity, at a toasty −23° C (−9.4° F).

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May 25, 2019

Origami-inspired materials could soften the blow for reusable spacecraft

Posted by in categories: materials, space travel

Space vehicles like SpaceX’s Falcon 9 are designed to be reusable. But this means that, like Olympic gymnasts hoping for a gold medal, they have to stick their landings.

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May 24, 2019

Lithium doesn’t crack under pressure, it transforms

Posted by in categories: materials, quantum physics

Using cutting-edge theoretical calculations performed at NERSC, researchers at Berkeley Lab’s Molecular Foundry have predicted fascinating new properties of lithium—a light alkali metal that has intrigued scientists for two decades with its remarkable diversity of physical states at high pressures.

“Under standard conditions, is a simple metal that forms a textbook crystalline solid. However, scientists have shown that when you put a lithium crystal under , the atomic structure changes and, somewhat counterintuitively, its conductivity drops, becoming less metallic,” said Stephanie Mack, a graduate student research assistant at Berkeley Lab and first author of the study, published in PNAS. “We’ve discovered it also becomes topological, with electronic properties similar to graphene.”

Topological materials are a recently discovered class of solids that display exotic properties, such as having insulating interiors yet highly conductive surfaces, even when deformed. They are exciting for potential applications in next-generation electronics and quantum information science. According to coauthors Sinéad Griffin and Jeff Neaton, lithium becomes topological at high but experimentally achievable pressures, comparable to one-quarter of the pressure at the Earth’s center.

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May 23, 2019

For this metal, electricity flows, but not the heat

Posted by in category: materials

There’s a known rule-breaker among materials, and a new discovery by an international team of scientists adds more evidence to back up the metal’s nonconformist reputation. According to a new study led by scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and at the University of California, Berkeley, electrons in vanadium dioxide can conduct electricity without conducting heat.

The findings, to be published in the Jan. 27 issue of the journal Science, could lead to a wide range of applications, such as thermoelectric systems that convert waste from engines and appliances into electricity.

For most metals, the relationship between electrical and thermal conductivity is governed by the Wiedemann-Franz Law. Simply put, the law states that good conductors of electricity are also good conductors of heat. That is not the case for metallic , a material already noted for its unusual ability to switch from an insulator to a metal when it reaches a balmy 67 degrees Celsius, or 152 degrees Fahrenheit.

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May 23, 2019

Behold the mayo: Experiments reveal ‘instability threshold’ of elastic-plastic material

Posted by in categories: engineering, materials

Arindam Banerjee, an associate professor of mechanical engineering and mechanics at Lehigh University, studies the dynamics of materials in extreme environments. He and his team have built several devices to effectively investigate the dynamics of fluids and other materials under the influence of high acceleration and centrifugal force.

One area of interest is Rayleigh-Taylor instability, which occurs between materials of different densities when the density and pressure gradients are in opposite directions creating an unstable stratification.

“In the presence of gravity—or any accelerating field—the two materials penetrate one another like ‘fingers,’” says Banerjee.

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May 23, 2019

Robots activated by water may be the next frontier

Posted by in categories: materials, robotics/AI

New research from the laboratory of Ozgur Sahin, associate professor of biological sciences and physics at Columbia University, shows that materials can be fabricated to create soft actuators—devices that convert energy into physical motion—that are strong and flexible, and, most important, resistant to water damage.

“There’s a growing trend of making anything we interact with and touch from materials that are dynamic and responsive to the environment,” Sahin says. “We found a way to develop a material that is water-resistant yet, at the same time, equipped to harness water to deliver the force and motion needed to actuate .”

The research was published online May 21 in Advanced Materials Technologies.

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May 23, 2019

Hemp Derived Carbon Nanosheets Better Than Graphene

Posted by in category: materials

https://youtube.com/watch?v=49JB_pyPEic

Researchers have created carbon nanosheets for use as supercapacitors with waste hemp fibres, and can do this at 1/1000th of the cost of graphene!

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