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| Award-winning energy harvester brings practical applications closer Posted: 02 Dec 2011 04:24 PM PST Although the idea of harvesting ambient energy from the environment and using it to generate electricity is alluring, most of the technology so far is capable of generating only very small amounts of power – on the order of microwatts to a few milliwatts with very low conversion efficiency. But a new piezoelectric energy-harvesting transducer shows that the technology is significantly improving. Researchers have predicted that 1-3 watts can be generated from a person walking when wearing a pair of shoes integrated with the new energy harvester, which is enough to power a soldier's portable communication devices on the battlefield, among other applications.
The piezoelectric energy-harvesting transducer was developed by a team of researchers led by Dr. Tian Bing Xu from the National Institute of Aerospace in Hampton, Virginia, in collaboration with NASA Langley Research Center, North Carolina State University, Stony Brook University, and TRS Technologies. The hybrid device combines two types of piezoelectric multilayer elements (one straight inner element sandwiched between two curved outer elements) with synergistically integrated force magnification, leading to advantages in several areas. Most notably, the transducer produces 19 times more electrical energy than current top piezoelectric transducers, and up to 1,000 times more electrical energy than a regular piezoelectric beam. Also, while the best piezoelectric transducers have mechanical-to-electrical conversion efficiencies of less than 7%, the new transducer achieves an efficiency of 26%. These improvements recently resulted in the new piezoelectric harvester winning the award for Best Technical Development of an Energy Harvesting Device at the conference of Energy Harvesting and Storage USA 2011, in Boston, MA, on November 15-16, 2011. This category was judged on which organization had made the most significant technical achievement in energy harvesting over the past 18 months. The awards are part of the IDTechEx annual conference of Energy Harvesting and Storage USA, which was attended by over 360 people from 16 countries and featured 40 exhibitors. The researchers have described the new piezoelectric harvester in more detail in a paper that is currently under NASA internal review. In a short description available on the website of Lei Zuo, coauthor and a professor at the State University of New York at Stony Brook, the researchers highlight a few important features that contribute to the device's superior performance. For one, the curved outer piezoelectric elements are relatively soft and bendable, resulting in more deformation (and absorbing greater mechanical energy) under a given applied force. The device also does a better job of coupling this mechanical energy into the piezoelectric materials since minimal non-piezoelectric materials are used. Another advantageous characteristic is that, when a force is applied vertically onto the device, the forces of both the straight and curved elements are amplified to the sides. This design feature enables the device to generate 2-3 orders of magnitude more electric charges under a given amount of vibration. "As we mentioned in the pending paper, the critical challenge for piezoelectric energy harvesting is how to harvest electrical power on the order of tens of milliwatts to several watts, which is good enough for powering most portable devices, from any kinds of vibration and motion at any ranges of vibration frequencies (off-resonance mode harvesting technology is needed)," Xu toldPhysOrg.com. "The new piezoelectric transducer addresses several critical issues from energy absorption, coupling, and conversion efficiency to overcome those challenges." In the future, the researchers hope that the new piezoelectric harvesters will be able to harvest enough energy to power different types of portable devices from the environment. In addition to being used in shoes, the harvesters could have applications in infrastructure health monitoring systems and sensor networks. Although the transducer works best when harvesting vibrations at a certain resonance, its high efficiency enables it to still use off-resonant vibrations for low-power devices, such as some sensors. "Piezoelectric energy harvesting is a multidisciplinary issue to be addressed from the considerations of mechanical engineering, electrical engineering, material science, and system engineering," Xu said. "For each individual mechanical vibration or motion resource, a specific device is designed to get an optimized electrical energy output. Our team is confident that we can move the energy harvesting technology into a new era." (c) 2011 3tlink.info Share and Enjoy• Facebook • Twitter • LinkedIn • Digg • Delicious • StumbleUpon • Reddit • Google Buzz • FriendFeed • MySpace • Add to favorites • Email • Print • PDF |
| YouTube renovates website with a new look, format Posted: 02 Dec 2011 04:14 PM PST YouTube has reprogrammed its website to make it easier for viewers to find and watch their favorite channels.
The facelift, unveiled Thursday, is the latest step in YouTube’s attempt to make the Internet’s most popular video site as easy to navigate and as compelling to watch as cable TV. In the process, YouTube owner Google Inc. hopes to make money selling ads. As part of the redesign, YouTube is replacing its staid white background with a touch of gray. The changes are part of the biggest renovation that YouTube has undertaken since Google bought the site for $1.76 billion five years ago. Although Google has been steadily adding more frills to YouTube since that acquisition, the videos on the site often were stitched in a crazy quilt that often required visitors to do a lot of searching to find what they wanted. Google also has been sprucing up other products in recent months, including its Gmail service and news section. YouTube’s website has been reorganized to display three main vertical columns instead of scattering clips in horizontal rows. The left of the page is devoted to a column that can be customized to feature a viewer’s favorite channels and monitor the videos being posted by their friends on social networks, including Facebook – a rival to Google’s own Plus service. The effort to highlight channels comes a few weeks after YouTube agreed to invest $100 million in original programming from about 100 celebrities, media companies and video entrepreneurs. Most of these channels will debut next year. YouTube hopes additional advertising will enable it to reap a profit from the investment. The middle of YouTube’s new home page is where videos can be played. The selection will change as viewers click on a different channel included in their lists in the left column. The far right column will recommend other videos, based on what kind of clips that viewers have watched in the past. Bringing more professionally-produced content and more organization toYouTube has become more important since last year’s introduction of Google TV – an attempt to seamlessly blend conventional television programming with Web surfing. YouTube’s more streamlined look might make the site more attractive to watch on large-screen TVs using Google’s product or other connections to the Internet. Google TV has struggled so far, partly because major Hollywood networks such as News Corp.’s Fox and The Walt Disney Co.’s ABC have blocked their content from the platform because they think it will undercut their advertising revenue and fees from pay-TV distributors such as Comcast Corp. and DirecTV. — Online: YouTube’s explanation for the redesign: http://youtube-global.blogspot.com/ (c) 2011 3tlink.info
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(Left) A diagram of the piezoelectric harvester with one straight inner piezoelectric multilayer stack (SIPMS) and two curved outer piezoelectric multilayer stacks (COPMSs). (Right) A photo of the first piezoelectric harvester prototype. Image credit: Tian Bing Xu, et al.
This screen grab provided by Google Inc. on Thursday, Dec. 1, 2011 shows the newly reprogrammed YouTube website. The facelift, unveiled Thursday, is the latest step in YouTube’s attempt to make the Internet’s most popular video site as easy to navigate and as compelling to watch as cable TV. In the process, YouTube owner Google Inc. hopes to make money selling ads.| You are subscribed to email updates from 3 Technology Link To stop receiving these emails, you may unsubscribe now. | Email delivery powered by Google |
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