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Archive for the ‘materials’ category: Page 113

Jul 8, 2022

Physicists discover a ‘family’ of robust, superconducting graphene structures

Posted by in categories: materials, particle physics

Martin ChartrandListen to the sound, more like a musket than a 3D printed plastic gun.

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Jul 7, 2022

Marsquakes reveal the Red Planet boasts a liquid core half its diameter

Posted by in categories: materials, space

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.

Jul 7, 2022

Scientists Have Created Worms That Can Kill Cancer Cells

Posted by in categories: biotech/medical, materials

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.

Jul 6, 2022

Scientists baffled by magnetic material that freezes when heated up

Posted by in categories: materials, particle physics

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.

Jul 6, 2022

Physicists see electron whirlpools for the first time

Posted by in categories: materials, particle physics

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, —the particles are so small that any 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.

Jul 5, 2022

Magnetic spins that ‘freeze’ when heated: nature in the wrong direction

Posted by in categories: materials, particle physics

Physicists observed a strange new type of behaviour in a magnetic material when it’s heated up. The magnetic spins ‘freeze’ into a static pattern when the temperature rises, a phenomenon that normally occurs when the temperature decreases. They publish their findings in Nature Physics on July 4th.

The researchers discovered the phenomenon in the material neodymium, an element that they described several years ago as a ‘self-induced spin glass’. Spin glasses are typically alloys where iron atoms for example are randomly mixed into a grid of copper atoms. Each iron atom behaves like a small magnet, or a spin. These randomly placed spins point in all kinds of directions.

Unlike conventional spin glasses, where there is random mixing of magnetic materials, neodymium is an element and without significant amounts of any other material, shows glassy behavior in its crystalline form. The spins form patterns that whirl like a helix, and this whirling is random and constantly changes.

Jul 5, 2022

Ultra-low-energy programmable non-volatile silicon photonics based on phase-change materials with graphene heaters

Posted by in categories: energy, materials

A non-volatile silicon photonics switch based on phase-change materials actuated by graphene heaters shows a switching energy density that is within an order of magnitude of the fundamental thermodynamic limit.

Jul 3, 2022

A gentler, more precise laser cutting technique

Posted by in categories: energy, materials

Laser cutting techniques are usually powered by high energy beams, so hot that they melt most materials. Now scientists from McGill University have developed a gentler, more precise technique using low-power visible light.

Jul 2, 2022

Programmable & Smart Matter

Posted by in categories: futurism, materials

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The future may see advancements in claytronics, memory metals, and catoms to allow shapeshifting materials that can take on any form and perform any job — possibly even taking on human form itself.

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Jul 2, 2022

Methane converted into methanol at room temperature — just add light

Posted by in categories: climatology, materials

Scientists have developed an efficient new way to convert methane into methanol at room temperature. The technique could help reduce greenhouse gas emissions and provide a cleaner way to make key products.

While carbon dioxide gets most of the attention, it’s not the only greenhouse gas changing the Earth’s climate. Methane is emitted in smaller amounts but is 34 times more potent, so reducing its levels remains a priority. Excess methane from industrial processes is often burned off, but that produces CO2.

A commonly sought alternative is to convert methane into methanol, which can be used to make a range of products like fuels, plastics and construction materials. The problem is, the conversion process usually requires high temperatures and pressures, which makes it energy-intensive.