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January 29th, 2013

Other materials stories that may be of interest

Published on January 29th, 2013 | By: Peter Wray

Lots of interesting research occurring:

Researchers create glexible, nanoscale ‘bed of nails’ for possible drug delivery

Researchers at North Carolina State University have come up with a technique to embed needle-like carbon nanofibers in an elastic membrane, creating a flexible “bed of nails” on the nanoscale that opens the door to development of new drug-delivery systems. The research community is interested in finding new ways to deliver precise doses of drugs to specific targets, such as regions of the brain. One idea is to create balloons embedded with nanoscale spikes that are coated with the relevant drug. Theoretically, the deflated balloon could be inserted into the target area and then inflated, allowing the spikes on the balloon’s surface to pierce the surrounding cell walls and deliver the drug. The balloon could then be deflated and withdrawn. But to test this concept, researchers first needed to develop an elastic material that is embedded with these aligned, nanoscale needles. That’s where the NC State research team came in. The researchers first “grew” the nanofibers on an aluminum bed, or substrate. They then added a drop of liquid silicone polymer. The polymer, nanofibers and substrate were then spun, so that centrifugal force spread the liquid polymer in a thin layer between the nanofibers—allowing the nanofibers to stick out above the surface. The polymer was then “cured,” turning the liquid polymer into a solid, elastic membrane. Researchers then dissolved the aluminum substrate, leaving the membrane embedded with the carbon nanofibers “needles.”

New material harvests energy from water vapor

MIT engineers have created a new polymer film that can generate electricity by drawing on a ubiquitous source: water vapor. The new material changes its shape after absorbing tiny amounts of evaporated water, allowing it to repeatedly curl up and down. Harnessing this continuous motion could drive robotic limbs or generate enough electricity to power micro- and nanoelectronic devices, such as environmental sensors. The new film is made from an interlocking network of two different polymers. One of the polymers, polypyrrole, forms a hard but flexible matrix that provides structural support. The other polymer, polyol-borate, is a soft gel that swells when it absorbs water. The film harvests energy found in the water gradient between dry and water-rich environments. When the 20-micrometer-thick film lies on a surface that contains even a small amount of moisture, the bottom layer absorbs evaporated water, forcing the film to curl away from the surface. Once the bottom of the film is exposed to air, it quickly releases the moisture, somersaults forward, and starts to curl up again. As this cycle is repeated, the continuous motion converts the chemical energy of the water gradient into mechanical energy.

Ultrastable glasses from in silico vapor deposition

(Nature Materials) Recent experiments indicate that glasses prepared by vapour deposition onto a substrate can exhibit remarkable stability, and might correspond to equilibrium states that could hitherto be reached only by glasses aged for thousands of years. Here we create ultrastable glasses by means of a computer-simulation process that mimics physical vapour deposition. These stable glasses have, far below the conventional glass-transition temperature, the properties expected for the equilibrium supercooled liquid state, and optimal stability is attained when deposition occurs at the Kauzmann temperature. We also show that the glasses’ extraordinary stability is associated with distinct structural motifs, in particular the abundance of regular Voronoi polyhedra and the relative lack of irregular polyhedra.

Glass that bends the rules of manufacturing

(Materials Review) Corning developed a thin, flexible glass, but the real breakthrough was figuring out how to mass-produce it. In 2011, a Corning researcher named Terry Ott faced a problem that nobody else had needed to solve in the company’s 160-year history: how to make sheets of glass that could be rolled onto spools. The challenge arose because Corning had developed a new kind of glass, known as Willow, which is as thin as a sheet of paper and acts a bit like it, too-if you shake it, it will rattle, and it can bend enough to be spooled. It could be the basis for displays in thinner, lighter cell phones and tablets-or for entirely new products, like displays that fit the curve of your wrist. Willow, which is one-third as thick as Gorilla Glass, would be a meaningless breakthrough if Corning couldn’t figure out how to make it in large quantities-and in a way that customers could use on their own production lines. The way Corning solved the problem of mass-producing Willow helps illustrate the extent to which technological innovation depends on close connections between R&D and manufacturing.

Just add water: Using nano-sized silicon produce hydrogen on demand

Super-small particles of silicon can react with water to produce hydrogen almost instantaneously, according to University at Buffalo researchers. In a series of experiments, the scientists created spherical silicon particles about 10 nanometers in diameter. When combined with water, these particles reacted to form silicic acid and hydrogen. The reaction didn’t require any light, heat, or electricity, and also created hydrogen about 150 times faster than similar reactions using 100-nanometer-wide silicon particles, and 1,000 times faster than bulk silicon, according to the study. “With further development, this technology could form the basis of a ‘just add water’ approach to generating hydrogen on demand,” says researcher Paras Prasad, executive director of UB’s Institute for Lasers, Photonics and Biophotonics. “The most practical application would be for portable energy sources.” The speed at which the 10-nanometer particles reacted with water surprised the researchers. In under a minute, these particles yielded more hydrogen than the 100-nanometer particles yielded in about 45 minutes. The maximum reaction rate for the 10-nanometer particles was about 150 times as fast. Though it takes significant energy and resources to produce the super-small silicon balls, the particles could help power portable devices in situations where water is available and portability is more important than low cost.

Google files patent for transducer-based bone conduction audio in Project Glass

(Gizmag) A USPTO patent application suggests that Google is planning to use bone conduction audio with its Project Glass headset. Google Glass is an augmented reality headset. Bone conduction transmits audio directly to the innermost part of the ear by means of a transducer, usually placed on the bone just in front of the ear. This does away with the need for traditional headphones, has the advantage of increased privacy and reduces the risk of hearing loss. Google’s patent describes the technology as using “at least one vibration transducer located on [...] at least one side section.” If just one transducer makes its way into the final design, then it’s likely that the resulting mono audio would be more suited to things like notifications than media. Mountain View’s patent also suggests that no additional contact point will be required for its application of the tech. Instead, the transducer vibrates the “support structure” of the glasses, rather than directly vibrating the wearer.

A new zinc battery that could revolutionize wearables

(Gigaom) Picture a Nike FuelBand that’s just a small ring on your index finger, or a cell phone that’s as slim and pliable as a credit card. Those types of thin, tiny or just down right unusual shapes could be created if there were batteries that were both slim, flexible and also powerful enough to run the gadgets. It’s the batteries, it turns out, that are the main barrier to modern electronics design. But in a small, brightly-lit lab in an office park behind the Oakland Airport in Alameda, Calif., a young startup called Imprint Energy, is using research created at the University of California, Berkeley to develop just such a battery that could free gadget makers from the constraints of the standard lithium ion battery. Well, that’s the plan anyways. Using zinc, instead of lithium, and screen printing technology, Imprint Energy is already churning out low volumes of its ultrathin, energy-dense, flexible, and low cost rechargeable batteries for pilot customers.The problem is, it’s hard to make standard lithium ion batteries thin and flexible, explained Imprint Energy CEO Devin MacKenzie in an interview in the startup’s lab last week. There’s a “lot of packaging,” required to seal off the highly reactive lithium in the battery from the environment, says MacKenzie.

Boeing completes successful flight test for Ground-based Midcourse Defense System (with video)

(Alabama.com) Almost two years since a failed intercept during a flight test, the Ground-based Midcourse Defense system completed a successful fly-out mission last weekend, according to officials with Boeing. The non-intercept test was held last Sunday at Vandenberg Air Force Base in California and included the launch of a GMD ground-based interceptor carrying a next-generation Enhanced Exoatmospheric Kill Vehicle, or EKV. The test measured the EKV’s performance as to the vehicle during stressful space conditions. The data from the test will be used to assess the EKV’s design as well. Produced by Raytheon, the EKV allows the GMD to lock on and eliminate high-speed ballistic missile warheads in space using force of impact. Raytheon officials said the EKV performed as planned, maneuvering the interceptor to the appropriate altitude and closing velocity required for an intercept. The EKV has eight successful intercepts throughout its program life. GMD is the United States’ only defense against long-range ballistic missile threats. Boeing stopped flight tests in early 2011 after a guidance error caused a failed intercept in a December 2010 test.

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