A Lightweight Display Brings Instant Army Intelligence to Your Wrist
(The flexible, durable, wearable screen could soon be standard issue)
Around the Bend: The Army hopes to squeeze a backpack’s worth of tech into an armband display Bland Design
A special-ops soldier carries a slew of gadgets into battle. There's the GPS unit to pinpoint his squad's location, and a laptop for pulling up blueprints of terrorist compounds or infrared readings of buildings scoped out by robotic surveillance drones. With a radio and its five-pound battery, it's too much gear. But in a couple years, troops could lighten their load with a rugged, flexible, wrist-mounted display that's in development by the U.S. Army and HP Labs.
The solar-powered, bendable computer screen will allow for instant data and radio transmission, all in a half-pound unit, says David Morton, the program manager for flexible electronics at the Army Research Laboratory. The display's thin layer of transistors sends electric signals to an e-ink screen, which converts those signals into grayscale images, similar to the way the Amazon Kindle does. Unlike the Kindle, the two-by-three-inch display can bend to fit around the user's wrist because HP stamps the electronics and optical components onto pliable plastic. The process eliminates the need for the fragile glass backing used in the Kindle and other displays, says Carl Taussig, the director of information surfaces at HP. "You can strike these things with a mallet, and they just keep on working."
While the Army works on a color screen, troops will test the black-and-white device and provide feedback for the final version, which should be ready for military use by 2011.
Using Nano-Geometry to Create Better Concrete
(Nano-treated concrete could endure for millennia, and provide a solution for very-long-term nuclear containment)
Concrete Creep: This microscopic picture shows a speck of dust deforming concrete at the nano-scale Chris Bobko/North Carolina State, via Science News
The use of concrete dates back to ancient Rome, and the recipe hasn't changed much since then. Neither have some of concrete's drawbacks. In particular, the slow deformation known as "concrete creep" has afflicted structures from the Pantheon to the Pentagon. But MIT scientists believe they have solved the mystery of concrete creep, and thus opened the door to structures that will last tens of thousands of years.
The scientists, writing in The Proceedings of the National Academy of Sciences, claim that molecular-scale disturbances in the cement extrapolate into large-scale warping in concrete over time. By using denser cement, those nano-deformations could be reduced, lowering the rate of deformation by two or three orders of magnitude.
Right now, silica fumes, a common cement additive long known to strengthen concrete, has been proven to increase the density of cement, and thus the longevity of concrete. However, silica fumes only increase the density of cement by 87 percent. In the paper, the researchers mathematically calculated that the creep could potentially be slowed by as much as two and a half times. At that reduced rate of deformation, concrete currently estimated to last 100 years could last up to 16,000 years. One obvious use for such a long-lasting material would be building structures for containment of nuclear waste; the half-life of plutonium-239 is 24,000 years.
With rapid construction occurring all over China and India, and with America looking to renew an aging infrastructure, concrete is on everyone's mind. Applying this new discovery might give everyone a couple of millennia before they need to worry about concrete again.
Magnetochromatic Material Changes Color on Command
(Spinning magnetic microspheres creates instant color changes and rewritable displays)
In the future, signs will be instantly rewritable and walls will change color at the flip of a switch. A research team at the University of California at Riverside has created a new magnetically activated, instantly and reversibly color-changing material with potentially groundbreaking applications. The technology is based on that used by colorful birds, beetles, and butterflies: instead of static pigments, the material employs "structural color," which depends on the interference effects of light.
Although other methods for creating tunable structural color exist, their color-changing processes are slow and complicated, and involve internal adjustments. This new material is composed of microscopic polymer "magnetochromatic microspheres," or beads, whose structural stability allows for instant changes in color with "no change in the structure or intrinsic properties of the microspheres themselves," according to Yadong Yin, who led the study.
The beads' colors change in response to magnetic fields, which alter the relative orientation of the periodic arrays within them. This use of magnetic fields allows for "instant action, contactless control, and easy integration into electronic devices already in the market."
The color-changing beads can also be used to create environmentally friendly pigments for inks and paints. Yin, an assistant professor of chemistry, and his colleagues, plan to work next on the wide array of applications for which this material is so promising. "Rewritable energy-saving display units such as papers and posters are our main interests," says Yin in the announcement. "We will also try to develop a similar new material for chemical and biological sensors."