In-shoe device harvests energy created by walking

A new in-shoe device is designed to harvest the energy that is created by walking, and store it for use in mobile electronic devices
Although you may not be using a Get Smart-style shoe phone anytime soon, it is possible that your mobile phone may end up receiving its power from your shoes. University of Wisconsin-Madison engineering researchers Tom Krupenkin and J. Ashley Taylor have developed an in-shoe system that harvests the energy generated by walking. Currently, this energy is lost as heat. With their technology, however, they claim that up to 20 watts of electricity could be generated, and stored in an incorporated rechargeable battery.
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While the details of the energy-harvesting technology are proprietary, it is said to involve a process known as "reverse electrowetting," which was discovered by Krupenkin and Taylor. It converts mechanical energy to electricity via a microfluidic device, in which thousands of moving microdroplets (of an undisclosed non-toxic, inexpensive liquid) interact with "a groundbreaking nanostructured substrate." The process is said to have a power density of up to one kilowatt per square meter (10.76 sq. ft.), plus it works with a wide range of mechanical forces, and is able to output a wide range of currents and voltages.
The battery is hermetically sealed, for protection against water and dirt. In order to get the power from it to the phone or other mobile device, the two would have to be temporarily physically joined with a wire, although the researchers are also looking into the use of conductive textiles and wireless inductive coupling.

Besides directly powering the phone, the device could also serve as a mobile WiFi hotspot, linking the phone to a wireless network. Having its own hotspot constantly nearby could drastically increase the phone's battery life - this is because the phone would only need to transmit in a low-power standard such as Bluetooth in order to reach the device, which would then use its own battery (which would be continuously getting recharged, by walking) for the high-power long-range transmissions to the network. Krupenkin claims that this could allow phone batteries to last up to ten times longer than normal.
The U Wisconsin technology is currently in the process of being commercialized, through Krupenkin and Taylor's company, InStep NanoPower. If it does make it to the marketplace, it may have some competition - Dr. Ville Kaajakari is also developing a piezoelectric device for shoes, that generates power as its user walks.

Solid-state capacitor said to combine best qualities of batteries and capacitors

A method developed at Rice University allows bundles of vertically aligned single-wall carbon nanotubes to be transferred intact to a conductive substrate
Capacitors are able to charge and discharge more quickly than batteries, and can do so hundreds of thousands of times. Batteries, on the other hand, are able to store more energy than capacitors. There are also electric double-layer capacitors (EDLCs), otherwise known as supercapacitors, that can hold battery-like amounts of energy while retaining the charge/discharge speed of regular capacitors. EDLCs incorporate liquid or gel-like electrolytes, however, which can break down under hot or cold conditions. Now, a new solid-state supercapacitor developed at Houston's Rice University is using nanotechnology to get around that limitation.
The Rice researchers started out by growing an array of 15-20 nanometer bundles of single-walled carbon nanotubes, each up to 50 microns in length. This "nanotube forest" served to maximize the surface area available to electrons.
That array was subsequently transferred to a copper electrode, that included thin layers of gold and titanium to help with electrical stability and adhesion. In an atomic layer deposition process, the bundles (which served as the primary electrodes) were next doped with sulfuric acid to boost their conductivity. They were then covered with aluminum oxide, which served as a dielectric layer, and aluminum-doped zinc oxide, which acted as the counterelectrode. Finally, the circuit was completed with a top electrode of silver paint.

The Rice supercapacitor is reportedly stable and scalable, holds a charge under high-frequency cycling, and isn't adversely effected by harsh temperatures. It could also be incorporated into other materials, allowing for electric car bodies that double as batteries, or microrobots that serve as their own power supply.
"All solid-state solutions to energy storage will be intimately integrated into many future devices, including flexible displays, bio-implants, many types of sensors and all electronic applications that benefit from fast charge and discharge rates," said Cary Pint, who co-led the research.
Technology that combines the attributes of capacitors and batteries is also being developed at the University of Illinois, where scientists are creating nanostructured lithium-ion batteries that charge and discharge 10 to 100 times faster than regular li-ions.

International team discovers planet made of diamond

00:15 August 26, 2011

The 'diamond planet' orbiting the radio wave-emitting pulsar J1719-1438 (Image: Swinburne Astronomy Productions)
A girl's best friend may have just gotten a whole lot bigger with the news that an international research team has discovered a small planet they think may be made of diamond. Although the planet is calculated to have a diameter of less than 60,000 km - which is about five times the diameter of Earth - it has slightly more mass than Jupiter. With the planet likely to be made largely of oxygen and carbon, its high density means it is almost certainly crystalline, meaning that a large part of the planet may be similar to a diamond.
The discovery was made by a team of researchers from Australia, Germany, Italy, the U.K. and the U.S., led by the Swinburne University of Technology's Professor Matthew Bailes. Using the CSIRO Parkes radio telescope in Australia, Lovell radio telescope in the U.K. and one of the Keck telescopes in Hawaii, they identified an unusual star called a pulsar known as PSR J1719-1438 located 4,000 light-years away in the constellation of Serpens in our Milky Way galaxy.
Pulsars are small spinning stars only around 20 km (12 miles) in diameter that emit a beam of radio waves. As the star spins, the emitted radio waves sweep repeatedly over Earth where radio telescopes are able to detect a regular pattern of radio pulses.
The astronomers noticed that the arrival times of the pulses from PSR J1719-1438 were systematically modulated and concluded that the gravitational pull of a small companion planet orbiting the pulsar in a binary system was to blame. The modulations tell the astronomers that the planet orbits the pulsar in just two hours and ten minutes, and that the distance between the two objects is 600,000 km - which is a little less than the radius of our Sun.
Because if it were any bigger it would be ripped apart by the pulsar's gravity, they also know that the companion planet must be small at less than 60,000 km in diameter. With slightly more mass than Jupiter, which has a diameter of almost 143,000 km, it is the planet's high density that Professor Baines says provides a clue of its origin.
The researchers believe that the "diamond planet" is the remnant of a once-massive star, most of whose matter was siphoned off towards the pulsar. PSR J1719-1438 is what is known as a millisecond pulsar because it spins very fast - rotating more than 10,000 times a minute. It also has a mass roughly 1.4 times that of our Sun, yet is only 20 km in diameter.
With around 70 percent of millisecond pulsars having companions of some kind, astronomers think that it is the companion in its star form that transforms an old, dead pulsar into a millisecond pulsar by transferring matter and spinning it up to a very high speed. The result is a fast-spinning millisecond pulsar with a shrunken companion, which is most often a white dwarf. However, because PSR J1719-1438 and its companion are so close together, the researchers say the companion must be one that has lost its outer layers and over 99.9 percent of its original mass.
"This remnant is likely to be largely carbon and oxygen, because a star made of lighter elements like hydrogen and helium would be too big to fit the measured orbiting times," said the CSIRO's Dr Michael Keith (CSIRO), one of the research team members.
Although there are a lot of stars "twinkling like a diamond in the sky," don't expect "diamond planets" to be all that common.
"The rarity of millisecond pulsars with planet-mass companions means that producing such 'exotic planets' is the exception rather than the rule, and requires special circumstances," said Dr Benjamin Stappers from the University of Manchester.
The "diamond planet" discovery is reported in the journal Science.