Human gait could soon power portable electronics

ScienceDaily (Aug. 24, 2011) — If the vision of Tom Krupenkin and J. Ashley Taylor comes to fruition, one day soon your cellphone -- or just about any other portable electronic device -- could be powered by simply taking a walk.

In a paper appearing in the journal Nature Communications, Krupenkin and Taylor, both engineering researchers at the University of Wisconsin-Madison, describe a new energy-harvesting technology that promises to dramatically reduce our dependence on batteries and instead capture the energy of human motion to power portable electronics.

"Humans, generally speaking, are very powerful energy-producing machines," explains Krupenkin, a UW-Madison professor of mechanical engineering. "While sprinting, a person can produce as much as a kilowatt of power."

Grabbing even a small fraction of that energy, Krupenkin points out, is enough to power a host of mobile electronic devices -- everything from laptop computers to cell phones to flashlights. "What has been lacking is a mechanical-to-electrical energy conversion technology that would work well for this type of application," he says.

Current energy harvesting technologies are aimed at either high-power applications such as wind or solar power, or very low-power applications such as calculators, watches or sensors. "What's been missing," says Taylor, "is the power in the watts range. That's the power range needed for portable electronics."

Solar power, the researchers explain, can also be used to power portable electronics, but, unlike human motion, direct sunlight is usually not a readily available source of energy for mobile electronics users.

In their Nature Communications report, Krupenkin and Taylor describe a novel energy-harvesting technology known as "reverse electrowetting," a phenomenon discovered by the Wisconsin researchers. The mechanical energy is converted to electrical energy by using a micro-fluidic device consisting of thousands of liquid micro-droplets interacting with a novel nano-structured substrate.

This technology could enable a novel footwear-embedded energy harvester that captures energy produced by humans during walking, which is normally lost as heat, and converts it into up to 20 watts of electrical power that can be used to power mobile electronic devices. Unlike a traditional battery, the energy harvester never needs to be recharged, as the new energy is constantly generated during the normal walking process.

The initial development of this technology was funded by a National Science Foundation Small Business Innovation Research grant. Now Krupenkin and Taylor are seeking to commercialize the technology through a company they've established, InStep NanoPower.

In their work, Taylor and Krupenkin were inspired by severe limitations that current battery technology imposes on mobile electronics users. As any cellphone or laptop user knows, heavy reliance on batteries greatly restricts the utility of mobile electronic devices in many situations. What's more, many mobile electronics are used in remote areas of the world where electrical grids for recharging batteries are often not available. Cellphone users in developing countries often have to pay high fees to have cellphones charged. Similar problems face military and law enforcement personnel. Modern soldiers, for example, head into the field carrying as much as 20 pounds of batteries to power communications equipment, laptop computers and night-vision goggles.

The energy generated by the footwear-embedded harvester can be used in one of two ways. It can be used directly to power a broad range of devices, from smartphones and laptops to radios, GPS units, night-vision goggles and flashlights.

Alternatively, the energy harvester can be integrated with a Wi-Fi hot spot that acts as a "middleman" between mobile devices and a wireless network. This allows users to seamlessly utilize the energy generated by the harvester without having to physically connect their mobile devices to the footwear. Such a configuration dramatically reduces power consumption of wireless mobile devices and allows them to operate for much longer time without battery recharge, the Wisconsin researchers say.

"You cut the power requirements of your cellphone dramatically by doing this," says Krupenkin. "Your cellphone battery will last 10 times longer."

Even though energy harvesting is unlikely to completely replace batteries in the majority of mobile applications, the UW-Madison researchers believe it can play a key role in reducing cost, pollution and other problems associated with battery use. The hope, they say, is that the novel mechanical to electrical energy conversion process they pioneered can go a long way toward achieving that goal.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Wisconsin-Madison. The original article was written by Terry Devitt.

Journal Reference:

Tom Krupenkin, J. Ashley Taylor. Reverse electrowetting as a new approach to high-power energy harvesting. Nature Communications, 2011; 2: 448 DOI: 10.1038/ncomms1454

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Microscope on the go: Cheap, portable, dual-mode microscope uses holograms, not lenses

ScienceDaily (Aug. 30, 2011) — To serve remote areas of the world, doctors, nurses and field workers need equipment that is portable, versatile, and relatively inexpensive. Now researchers at the University of California at Los Angeles (UCLA) have built a compact, light-weight, dual-mode microscope that uses holograms instead of lenses. The team describes the new device in a paper published August 30 in the Optical Society's (OSA) open-access journal Biomedical Optics Express.

Their prototype weighs about as much as a medium-sized banana and fits in the palm of a hand. And, since it relies in part on mass-produced consumer electronics, all the materials to make it add up to between $50 and $100 USD.

It also has a two-in-one feature: a transmission mode that can be used to probe relatively large volumes of blood or water, and a reflection mode that can image denser, opaque samples. The spatial resolution for both modes is less than two micrometers -- comparable to that achieved by bulkier microscopes with low- to medium-power lenses.

"This is the first demonstration of essentially a hand-held version of a microscope that can do dual-mode imaging within a very compact and cost-effective form," says Aydogan Ozcan, an associate professor of electrical engineering and bioengineering at UCLA and senior author of the paper.

With just a small amount of training, doctors could use devices like these to improve health care in remote areas of the world with little access to diagnostic equipment, Ozcan says. The handheld microscope could help ensure water quality, test patients' blood for harmful bacteria, and even be used for semen-quality monitoring on animal farms.

It could also prove useful in health crises such as the recent outbreak of E. coli in Europe.

"It's a very challenging task to detect E. coli in low concentrations in water and food," Ozcan says. "This microscope could be part of a solution for field investigation of water, or food, or maybe pathogens in blood."

Part of the device's success is the weight it shed when researchers got rid of the bulkier, heavier, more expensive pieces that most microscopes rely on for collecting and focusing light: the lenses. Instead of lenses, this microscope uses holograms.

Holograms are formed when light bouncing off (or passing through) a three-dimensional object is made to interfere with a "reference beam," or light that has not hit the object. Consider this analogy: drop a stone into a still pond and the ripples will move outward in a circle. Drop two stones and the circular ripples will interfere with each other, making a new pattern of crests and troughs. A person (or computer) analyzing the interference pattern created by those two stones could trace the source back to the stones and recreate what had happened to make the waves.

The UCLA team's device uses a similar principle to recreate images from interfering light waves.

An inexpensive light source is divided into two beams -- one that interacts with microscopic cells or particles in the sample, and the other that does not. The beams then pass to an adjacent sensor chip, where their interference pattern is recorded.

Software then analyzes that pattern and recreates the path taken by the light that passed through or bounced off of the objects being imaged.

Each component of the device is fairly inexpensive, Ozcan says. The laser light could come from a $5 laser pointer. The sensor chip that collects that light is the same as the ones in the backs of iPhones and Blackberrys and costs less than $15 per chip. And the whole image-collecting system runs on two AA batteries.

Where the researchers have reduced weight and expense in doing away with lenses, they have added the power of the cloud. The microscope captures raw data; but a computer is required to reconstruct the images. Workers in the field could use their laptops to process the information or send it over the Internet or mobile phone networks to a remote server. Mobile phones could also have sufficient processing power to do the analysis on the spot.

Essentially, Ozcan says, "we are replacing an expensive and bulky, heavy component with computer codes."

The next steps for Ozcan's team include commercializing the device. Ozcan says he has founded a company that is developing this technology, trying to make a version of the microscopes that can be manufactured and sold to healthcare workers and hobbyists.

"Global health is a big field that requires better diagnostic tools, because resource-poor countries don't have the infrastructure for conducting essentially accurate diagnostic tests," Ozcan says. "There are so many problems that innovative solutions [like this microscope] would impact."

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Optical Society of America, via EurekAlert!, a service of AAAS.

Journal Reference:

Myungjun Lee, Oguzhan Yaglidere, Aydogan Ozcan. Field-portable reflection and transmission microscopy based on lensless holography. Biomedical Optics Express, 2011; 2 (9): 2721 DOI: 10.1364/BOE.2.002721

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

WOWee ONE Classic Portable Speaker

March 27, 2011 - Laptops and smartphones are more compact and more capable than ever, but the built-in sound from these mobile devices hasn't, in general, improved. If you need better audio quality on the go (whether for work or personal reasons), the WOWee ONE Classic portable speaker, with its impressive (and innovative) bass production is a great choice.

The WOWee ONE Classic portable speaker transforms any flat surface into a speaker, using an innovative gel pad on the bottom of the device to remarkably boost low bass frequencies. The result is a richer and warmer audio experience than you might expect from such a compact, portable device.

Although it's not the smallest or most lightweight portable speaker around, the WOWee ONE is one of the most satisfying and fun to use for gadget geeks and audiophiles (and, perhaps, engineering/physics majors as well). The WOWee ONE is cleverly designed to vibrate and transform the surfaces it's placed on into a makeshift subwoofer. Experimenting with the WOWee ONE is part of the fun: how does a song sound when the portable speaker is placed against a glass surface versus on a wooden one? Which materials brought out the best sound?

The WOWee ONE got lots of real-life testing in my household in the last few months. It can provide rich, loud sound on the go and also when entertaining groups of friends at home. We placed the speaker on an antique piano, hardwood floor, glass window, wooden coffee table with hollow drawers, and also held the speaker up against a thin wall (which sounded the best to us). WOWee makes a mount to secure the speaker to a wall or another favorite surface, so you can optimize the sound coming out of the speakers.

Whichever surface it was placed on, the sound coming out of the WOWee ONE was stunning--not tinny or weak like other portable speaker options. The unit is rechargeable via mini-USB port or power adapter and it can also last an incredible 20 hours or more on a charge.

At $79.99 MSRP at the time of this writing, the WOWee ONE is targeted for those mobile users who really care about the quality of the sound from their mobile devices. My only criticism of the speaker is that it's a bit heavy and thick for mobile users who want to travel light, but WOWee is coming out with a SLIM version that sacrifices some battery life (10 hours vs. 20) in exchange for being thinner and lighter.

Pick up a WOWee ONE and start experimenting with the sound transmission from various surfaces, and you should find that the portable speaker really delivers.

View the original article here

What is a Portable Device?

Sorry, I could not read the content fromt this page.

View the original article here