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Category: materials – Page 182

Living coral reefs consist of rigid porous “skeletons” inhabited by the tiny coral polyps that built them. A new research project aims to restore damaged reefs faster than ever, utilizing 3D-printed skeletons made of the same material as the real thing.

First of all, there have been other projects that attempted to encourage the regrowth of coral by placing artificial skeletons on existing reefs. In most cases, though, those skeletons were made of materials such as concrete or polymers.

This means that waterborne coral polyps arriving at the reef have had to secrete calcium carbonate onto the structures, in order to “make them their own.” Given that some corals grow at a rate of just a few millimeters per year, it can take quite a long time to rebuild reefs in this fashion.

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In the last few years, a class of materials called antiferroelectrics has been increasingly studied for its potential applications in modern computer memory devices. Research has shown that antiferroelectric-based memories might have greater energy efficiency and faster read and write speeds than conventional memories, among other appealing attributes. Further, the same compounds that can exhibit antiferroelectric behavior are already integrated into existing semiconductor chip manufacturing processes.

Now, a team led by Georgia Tech researchers has discovered unexpectedly familiar behavior in the antiferroelectric material known as zirconium dioxide, or zirconia. They show that as the microstructure of the material is reduced in size, it behaves similarly to much better understood materials known as ferroelectrics. The findings were recently published in the journal Advanced Electronic Materials.

Miniaturization of circuits has played a key role in improving memory performance over the last fifty years. Knowing how the properties of an antiferroelectric change with shrinking size should enable the design of more effective memory components.

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A team of physicists has discovered how DNA molecules self-organize into adhesive patches between particles in response to assembly instructions. Its findings offer a “proof of concept” for an innovative way to produce materials with a well-defined connectivity between the particles.

The work is reported in Proceedings of the National Academy of Sciences.

“We show that one can program particles to make tailored structures with customized properties,” explains Jasna Brujic, a professor in New York University’s Department of Physics and one of the researchers. “While , drills, and hammers must be controlled by humans in constructing buildings, this work reveals how one can use physics to make that ‘know’ how to assemble themselves.”

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Similar to grass stems, Lawrence Livermore National Laboratory (LLNL) scientists have created nanostrut-connected tube-in-tubes that enable stronger low-density structural materials.

Porous materials with engineered stretching-dominated lattice designs, which offer attractive mechanical properties with ultra-light weight and large surface area for wide-ranging applications, have recently achieved near-ideal linear scaling between stiffness and density.

In the new research, the team developed a process to transform fully dense, 3D-printed polymeric beams into graphitic carbon hollow tube-in-tube sandwich structures, where, similar to grass stems, the inner and outer are connected through a network of struts. The research is on the cover of the Oct. 25 issue of Nature Materials.

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The sharpest knives available are made of either steel or ceramic, both of which are man-made materials that must be forged in furnaces under extreme temperatures. Now, researchers have developed a potentially more sustainable way to make sharp knives: using hardened wood. The method, presented October 20th, 2,021 in the journal Matter, makes wood 23 times harder, and a knife made from the material is nearly three times sharper than a stainless-steel dinner table knife.

“The knife cuts through a medium-well done steak easily, with similar performance to a dinner table knife,” says Teng Li, the senior author of the study and a materials scientist at the University of Maryland. Afterward, the hardened wood knife can be washed and reused, making it a promising alternative to steel, ceramic, and disposable plastic knives.

Li and his team also demonstrated that their material can be used to produce wooden nails as sharp as conventional steel nails. Unlike steel nails, the wooden nails the team developed are resistant to rusting. The researchers showed that these wooden nails could be used to hammer together three boards without any damage to the nail. In addition to knives and nails, Li hopes that, in the future, the material can also be used to make hardwood flooring that is more resistant to scratching and wear.

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Scientists at Rice University have created a material that will protect steel from corrosion. In fact, it will also be flexible and heal itself when damaged.

This material will be used as a coating and is made from a lightweight sulfur-selenium alloy. It will be able to block moisture and chlorine-like zinc-and chromium-based coatings, protect steel under seawater-like conditions like polymer-based coatings, keep it from microbe-induced corrosion.

The experiments carried out before the results comprised putting small slabs of common mild steel coated with sulfur-selenium alloy in seawater for a month, along with an uncoated slab of steel as a control. The coated steel did not oxidize.

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The iron-based superconductor material, Ba1−xKxFe2As2. Vadim Grinenko, Federico Caglieris/KTH Royal Institute of Technology

Twenty years ago, scientists first predicted electron quadruplets. Now, KTH Professor Egor Babaev, with the aid of international collaborators, has revealed evidence of fermion quadrupling in a series of experimental measurements on the iron-based material, Ba 1−x Kx Fe 2 As 2.

This is the first-ever experimental evidence of this quadrupling effect and the mechanism by which this state of matter occurs.

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