Shape memory alloys and a kind of plastic crystal chill quickly under force or pressure. They could lead to eco-friendly fridges and air conditioners.
Category: materials – Page 209
Vanadium could be used for outer hulls of spaceships to absorb sun like energy or higher.
Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys with emphasis on the V-15Cr-5Ti alloy, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R&D) needs are defined.
The relatively high thermal conductivity and low thermal expansion coefficient of vanadium-base alloys, which result in lower thermal stresses for a given heat flux compared to most other candidate alloys, should enhance the reactor wall-load and lifetime capability. Since the mechanical strength of vanadium-base alloys is retained at relatively high temperatures, higher operating temperatures are projected for these alloys than for austenitic or ferritic steels. The refractory metals, including vanadium, characteristically exhibit good corrosion resistance in purified liquid metals. The vanadium alloys also exhibit favorable neutronic properties which include lower parasitic neutron absorption leading to better tritium breeding performance, lower bulk nuclear heating rates, and lower helium generation rates compared to the steels.
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.
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.
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
Posted in climatology, materials
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:
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 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, water filtration membranes have been around for years but have always been vulnerable to clogging from organic and inorganic materials 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 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 monomer 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.