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Category: materials – Page 280

A thermal invisibility cloak actively redirects heat

Light, sound, and now, heat — just as optical invisibility cloaks can bend and diffract light to shield an object from sight, and specially fabricated acoustic metamaterials can hide an object from sound waves, a recently developed thermal cloak can render an object thermally invisible by actively redirecting incident heat.

The system, designed by by scientists at the Nanyang Technological University (NTU) in Singapore, has the potential to fine-tune temperature distribution and heat flow in electronic and semiconductor systems. It has application in devices with high requirements for efficient dissipation and homogenous thermal expansion, such as high-power engines, magnetic resonance imaging (MRI) instruments, and thermal sensors.

“Because of its shape flexibility, the active thermal cloak might also be applied in human garments for effective cooling and warming, which makes a lot of sense in tropical areas such as Singapore,” said Prof. Baile Zhang of NTU.

Loofah-inspired aerogel efficiently filters microbes from water

Millions of people worldwide die every year from waterborne diseases because of a lack of affordable, practical disinfection technologies. To address this need, researchers have developed a strong, flexible filter out of a silica aerogel that efficiently kills bacteria, resists getting clogged, and needs just a quick dip in dilute bleach to renew its disinfecting properties.

Read about the loofah-inspired aerogel here: https://bit.ly/3lhulJo

Low-cost, functionalized silica material kills bacteria instantly and is easy to clean.

NASA’s New $10 Billion Telescope to Study Quasars and Their Host Galaxies in Three Dimensions

Supermassive black holes, which likely reside at the centers of virtually all galaxies, are unimaginably dense, compact regions of space from which nothing — not even light — can escape. As such a black hole, weighing in at millions or billions of times the mass of the Sun, devours material, it is surrounded by a swirling disk of gas. When gas from this disk falls towards the black hole, it releases a tremendous amount of energy. This energy creates a brilliant and powerful galactic core called a quasar, whose light can greatly outshine its host galaxy.

Astronomers widely believe that the energy from quasars is responsible for limiting the growth of massive galaxies. Shortly after the launch of NASA ’s James Webb Space Telescope, scientists plan to study the effect of three carefully selected quasars on their host galaxies in a program called Q3D.

A supermassive black hole is very small compared to its host galaxy — it’s the equivalent of a penny in relation to the size of the entire Moon. Still, supermassive black holes have an immense influence on the galaxies they inhabit.

The Biggest Frog that Ever Lived

Untangling the origins of Beelzebufo — the giant frog that lived alongside the dinosaurs — turns out to be one of the most bedeviling problems in the history of amphibians.

Thank you to these paleoartists for allowing us to use their wonderful illustrations:
Ceri Thomas: http://alphynix.tumblr.com/
Nobu Tamura: https://spinops.blogspot.com/
Julio Lacerda: https://252mya.com/gallery/julio-lacerda

This video features this paleogeographic map: Scotese, C.R., 2019. Plate Tectonics, Paleogeography, and Ice Ages, YouTube video: https://youtu.be/UevnAq1MTVA.

Here are the two of the papers we reference in this video:
Evans SE, Groenke JR, Jones MEH, Turner AH, Krause DW (2014) New Material of Beelzebufo, a Hyperossified Frog (Amphibia: Anura) from the Late Cretaceous of Madagascar. PLoS ONE 9: e87236. https://doi.org/10.1371/journal.pone.

Lappin, A.K., Wilcox, S.C., Moriarty, D.J. et al. Bite force in the horned frog (Ceratophrys cranwelli) with implications for extinct giant frogs. Sci Rep 7, 11963 (2017). https://doi.org/10.1038/s41598-017-11968-6

Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios

Continue reading “The Biggest Frog that Ever Lived” | >

You Could Win $25K Worth of 3D Printing Services

A start-up based in Berkeley, California, polySpectra, is attempting to make better materials for 3D printing. Their inaugural material, COR Alpha, promises to be a stronger and more durable material for digital light processing (DLP) printing. If it’s a compelling fit for your project, you could win $25,000 worth of 3D printing services from polySpectra.

In an attempt to spur the development of 3D printed projects with COR Alpha, polySpectra is holding the Make It Real 3D Printing Challenge. The challenge calls for submissions of designs that could benefit from the new material. The winner will receive $25,000 worth of polySpectra’s 3D printing services in the form of mentoring, design consultation, functional prototyping, qualification, testing and fabrication. Applications are due September 28.

Scientists create water filtration membranes that can clean themselves

Scientists at the Department of Energy’s (DOE) Argonne National Laboratory have developed a light-activated coating for filtration membranes—the kind used in water treatment facilities, at semiconductor manufacturing sites and within the food and beverage industry—to make them self-cleaning, eliminating the need to shut systems down in order to repair them.

Cheap and effective, have been around for years but have always been vulnerable to clogging from organic and that stop up its pores over time, a phenomenon known as fouling.

“Anything you stick in water is going to become fouled sooner or later,” said Argonne senior scientist Seth Darling.

A new kind of plastic that is able to maintain its original qualities when recycled

A team of researchers from the U.S., China, and Saudi Arabia has developed a new kind of plastic that is able to maintain its original qualities when recycled. In their paper published in the journal Science Advances, the group describes how the new plastic is made and how well it did when tested for recyclability.

For many years, plastics have been seen as a highly desirable modern advancement—they are light, strong, bendable when needed, and can be used in a very wide variety of applications. The down side to plastics, of course, is that they do not recycle very well and they take a very long time to decay. This has led to millions of tons of plastic waste winding up in landfills and in the water table. Because of that, scientists have been hard a work looking for a new kind of plastic that has all the advantages of the old plastic but also can be easily recycled. In this new effort, the researchers claim to have developed just such a plastic.

The researchers made the new plastic by preparing a bridged bicyclic thiolactone from a bio-based olefin carboxylic acid. The result was a plastic (they called PBTL) that had all the qualities of traditional plastics. They next tested their plastic by conducting bulk depolymerization at 100°C using a catalyst. Testing of the result showed the PBTL had been broken down into its original monomer. They followed that up by breaking down samples of PBTL (using a catalyst) at room temperature. And once again, close examination showed the sample had been broken down to the original monomer.

Kepler’s supernova remnant: Debris from stellar explosion not slowed after 400 years

Astronomers have used NASA’s Chandra X-ray Observatory to record material blasting away from the site of an exploded star at speeds faster than 20 million miles per hour. This is about 25,000 times faster than the speed of sound on Earth.

Kepler’s supernova remnant is the debris from a detonated star that is located about 20,000 light years away from Earth in our Milky Way galaxy. In 1604 early astronomers, including Johannes Kepler who became the object’s namesake, saw the supernova explosion that destroyed the star.

We now know that Kepler’s supernova remnant is the aftermath of a so-called Type Ia supernova, where a small dense star, known as a white dwarf, exceeds a critical mass limit after interacting with a companion star and undergoes a thermonuclear explosion that shatters the white dwarf and launches its remains outward.

Metamaterials Generate Gecko-Like Adhesive Force

Circa 2012

Back in 1871, James Clerk Maxwell predicted that light exerts a force on any surface it hits. This radiation pressure was experimentally discovered some 30 years later and has since emerged as a hugely important force that is now exploited in systems such as solar sails and laser cooling.

Today, John Zhang and buddies at the University of Southampton in the UK go one better. These guys predict that a far more powerful optical force can exist between a metal or dielectric plate and a metamaterial, a substance with optical properties that have been engineered to control light in specific ways.

Metamaterials can be designed so they allow tiny oscillations of electrons called plasmons to exist on their surfaces. The oscillations are tiny–measured in nanometres, that’s about the same as the wavelength of visible light.

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