Tiny filters measuring just one-atom thick might be the next generation of technology that efficiently separates salt and impurities from water. Researchers report that they have successfully punched subnanoscale holes in graphene, the sheets of bound carbon atoms known to be one of the strongest materials on Earth.
They fired metal ions at the graphene to disrupt the bonds between carbon atoms, which naturally form into hexagonal rings that look like chicken wire. The graphene was then etched with a solution that dissolved the weakened bonds and formed densely packed pores.
“We bombard the graphene with gallium ions at high energy,” said Sean O’Hern, an MIT graduate student who led the research, in a university statement. “That creates defects in the graphene structure, and these defects are more chemically reactive.”
The second most popular beverage in the world, after water, is believed to be tea.
There are different kinds of tea, but green tea carries with it a slew of promised health benefits. And now, scientists have made a new discovery within a simple cup of green tea.
Engraving microscopic cracks in glass sheets can make it 200 times tougher than normal, McGill University mechanical engineers say. The insight could lead to improvements in regular glass objects like wine glasses or jars that don’t shatter when dropped, instead only deforming on impact.
Researchers took a clue from nature to uncover the fact that etching wavy lines in test glass slides prevented stress-induced cracks from spreading into the material’s failure. Their muse was the seemingly simple mother-of-pearl coating inside the shells of some mollusks.
This material is called nacre, and it is mostly composed of chalk, a brittle substance that normally disintegrates under the slightest pressure. But the organism constructs a biomaterial that is 3,000 times tougher than the weak chalk from which it is composed, writes François Barthelat, who runs McGill’s biomimetic materials lab and led the research. The secret is in how the creature builds nacre out of tiny tablets of chalk that are laid down in offset rows. This architecture, which is also seen in teeth and bones, counters a propagating crack by deflecting it and diffusing energy to surrounding tiles.
Artificial muscles that drive the powerful limbs or subtle facial expressions of robots can be made using nothing more than fishing line and sewing thread, researchers say. Such components work essentially the same way as toy airplanes powered by rubber bands.
"We can take a very inexpensive material that you can find at your local store and convert it to a powerful muscle that outperforms very complicated technologies," says Ray Baughman, a materials scientist and director of the University of Texas at Dallas NanoTech Institute.
The scientists imagine their new technology will find use in applications where superhuman strength is desired, such as in robots, exoskeletons and prosthetic limbs. For example, by twisting a bundle of polyethylene fishing lines, each about 10 times the width of a human hair, a coiled polymer muscle results that can lift 16 pounds, and 100 of these muscles operating in parallel much like natural muscles could lift about 1,600 pounds, Baughman says.
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