Tag Archives: materials

Invisibility update…

lolcatsThe intriguing development of materials that are effectively invisible thanks to a phenomenon called negative refraction continues apace.

This article from a Physorg has further details:

Applications for a metamaterial entail altering how light normally behaves. In the case of invisibility cloaks or shields, the material would need to curve light waves completely around the object like a river flowing around a rock. For optical microscopes to discern individual, living viruses or DNA molecules, the resolution of the microscope must be smaller than the wavelength of light

The theory behind negative refraction seems fairly complex – but it’s interesting to imagine what can be done by “altering how light normally behaves” and the possibility of viewing live viruses is also interesting.

[stories from Physorg and BBC News][image from PhoebeJ on flickr]

Cast aside your iron for super-paper!

Stack of paperHere’s a little something I missed the other week: a Swedish research team are working to develop “nanopaper”, a material based on wood-pulp cellulose nanofibres that can be stronger than cast iron.

The new method involves breaking down wood pulp with enzymes and then fragmenting it using a mechanical beater. The shear forces produced cause the cellulose to gently disintegrate into its component fibres.

The end result is undamaged cellulose fibres suspended in water. When the water is drained away Berglund found that the fibres join together into networks held by hydrogen bonds, forming flat sheets of “nanopaper”.

So what, you may be thinking. Well, as Charlie Stross suggested, if the current generation of 3D-printing/fabrication systems (like RepRap) swapped the soft plastics they currently extrude with for the nanopaper formula:

“… the future may turn out to be made of papier maché.”

Anyone have any idea how recyclable this cellulose nanopaper would be by comparison to plastics or steel? [image by Tina Raval]

‘Beetlepunk’ – biomimicry and the photonic weevil

Lamprocyphus augustus - photonic weevilWith designers and engineers increasingly turning to the natural world for inspiration, biomimicry is an increasingly important part of the sciences. Author Janine Beynus offers an outline of the discipline’s key principles;

The core idea is that nature, imaginative by necessity, has already solved many of the problems we are grappling with. Animals, plants, and microbes are the consummate engineers. They have found what works, what is appropriate, and most important, what lasts here on Earth. This is the real news of biomimicry: After 3.8 billion years of research and development, failures are fossils, and what surrounds us is the secret to survival.

Like the viceroy butterfly imitating the monarch, we humans are imitating the best adapted organisms in our habitat. We are learning, for instance, how to harness energy like a leaf, grow food like a prairie, build ceramics like an abalone, self-medicate like a chimp, create color like a peacock, compute like a cell, and run a business like a hickory forest.

As an real-world illustration of biomimetic principles, this morning, Wired‘s Brandon Keim presented a design problem from the field of optical computing;

For decades, scientists have dreamed of computer chips that manipulate light rather than electricity. Unlike electrons, photons can cross paths without interfering with each other, so optical chips could compute in three dimensions rather than two, crunching data in seconds that now takes weeks to process.

For now, though, optical computing remains a dream. The chips require crystals that channel photons as nimbly as silicon channels electrons — and though engineers have been able to imagine the ideal photonic crystal, they’ve been unable to build it.

Earlier this month, a team of American material scientists found a biomimetic solution in the body of Lamprocyphus augustus – a Brazilian weevil. According to the research,

the inch-long Brazilian beetle’s iridescent green scales are composed of chitin arranged by evolution in precisely the molecular configuration that has confounded the would-be fabricators of optical computers.

The “scales’ molecular arrangement, which had the same pattern as the atoms of carbon in a diamond.” So, with real diamonds too dense for the task, and artificial diamonds taking months to construct, the L. augustus scales offer a quick and easy solution.

Of course – as co-author Michael Bartl notes – optical computers won’t use actual weevil scales. The plan is to use the scales as a mould, replacing the chitin with something more suitable for the industrial context.

For someone approaching the issue from a science fictional standpoint, this sent my mind careering down a whole new avenue of speculation. Imagine a world in which Bartl’s mould plan is ineffective. Here, much of the high-end computing infrastructure is entirely dependent on this tiny Brazilian insect.

Our protagonists are rogue entomologists, forced to balance the “bug bounties” offered by the military-industrial complex with the ‘pure’ research of their underfunded university departments. Academic soul-searching, Brazilian protesters, university politics, intellectual property wrangles, and a left-wing subtext. It’s got it all.

I call it ‘Beetlepunk’. 😀

Finally, if this whole ‘biomimicry’ thing strikes you as interesting, be sure to check out Janine Beynus’ presentation from TED 2005. She’s a skilled orator, and her TED talk is a really good way of getting your head around the subject.

[Image by Barbara Strnadova at God of Insects]

Scientist creates dark matter in the lab!

Black Corvette No, not that dark matter, but rather the darkest known material, about four times darker than the previous record holder. (Via PhysOrg.)

It’s a carpet of carbon nanotubes that only reflects 0.045 percent light, making it, as the Houston Chronicle puts it, “100 times darker than a black-painted Corvette,” (which seems like a fairly imprecise measurement standard, but never mind). The previous darkest known material was a nickel and phosphorus alloy that reflected about 0.16 percent of light.

The material’s ability to absorb light could be beneficial to solar panels and, since it minimizes the scattering of light, it could also benefit telescope manufacturers.

It also minimizes the scattering of light, making it a potential boon to telescope manufacturers.

(And, yes, you’re absolutely right: I posted this just so I could use that headline. The photo was a bonus.)

(Image: Wikimedia Commons.)

[tags]physics, materials, light[/tags]